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Sample records for acid removal process

  1. Improved Processes to Remove Naphthenic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Aihua Zhang; Qisheng Ma; Kangshi Wang; Yongchun Tang; William A. Goddard

    2005-12-09

    In the past three years, we followed the work plan as we suggested in the proposal and made every efforts to fulfill the project objectives. Based on our large amount of creative and productive work, including both of experimental and theoretic aspects, we received important technical breakthrough on naphthenic acid removal process and obtained deep insight on catalytic decarboxylation chemistry. In detail, we established an integrated methodology to serve for all of the experimental and theoretical work. Our experimental investigation results in discovery of four type effective catalysts to the reaction of decarboxylation of model carboxylic acid compounds. The adsorption experiment revealed the effectiveness of several solid materials to naphthenic acid adsorption and acidity reduction of crude oil, which can be either natural minerals or synthesized materials. The test with crude oil also received promising results, which can be potentially developed into a practical process for oil industry. The theoretical work predicted several possible catalytic decarboxylation mechanisms that would govern the decarboxylation pathways depending on the type of catalysts being used. The calculation for reaction activation energy was in good agreement with our experimental measurements.

  2. Humic acid removal from aqueous solutions by peroxielectrocoagulation process

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Yazdanbakhsh

    2015-06-01

    Full Text Available Background: Natural organic matter is the cause of many problems associated with water treatment such as the presence of disinfection by-products (DBPs and membrane fouling during water filtration. In this study, the performance of the peroxi-electrocoagulation process (PEP was investigated for the removal of humic acids (HAs from aqueous solutions. Methods: PEP was carried out for the removal of HA using a plexiglas reactor with a volume of 2 L and fitted with iron electrodes and a direct current supply (DC. Samples were taken at various amounts of pH (2-4, current density (1 and 2A/cm2, hydrogen peroxide (50-150 mg/L and reaction time (5-20 minutes and then filtered to remove sludge formed during reaction. Finally, the HA concentration was measured by UV absorbance at 254 nm (UV254. Results: Results indicated that increasing the concentration of H2O2 from 50 to 150 mg/L increased HA removal efficiency from 83% to 94.5%. The highest removal efficiency was observed at pH 3.0; by increasing the pH to the alkaline range, the efficiency of the process was reduced. It was found that HA removal efficiency was high in current density 1A/cm2. Increasing current density up to 1 A cm-2 caused a decrease in removal efficiency. Results of this study showed that under the optimum operating range for the process ([current density] = 1A/cm2, [hydrogen peroxide concentration] = 150 mg/L, [reaction time]= 20 minutes and [pH]= 3.0, HA removal efficiency reached 98%. Conclusion: It can be concluded that PEP has the potential to be utilized for cost-effective removal of HA from aqueous solutions.

  3. Processes to remove acid forming gases from exhaust gases

    Science.gov (United States)

    Chang, S.G.

    1994-09-20

    The present invention relates to a process for reducing the concentration of NO in a gas, which process comprises: (A) contacting a gas sample containing NO with a gaseous oxidizing agent to oxidize the NO to NO[sub 2]; (B) contacting the gas sample of step (A) comprising NO[sub 2] with an aqueous reagent of bisulfite/sulfite and a compound selected from urea, sulfamic acid, hydrazinium ion, hydrazoic acid, nitroaniline, sulfanilamide, sulfanilic acid, mercaptopropanoic acid, mercaptosuccinic acid, cysteine or combinations thereof at between about 0 and 100 C at a pH of between about 1 and 7 for between about 0.01 and 60 sec; and (C) optionally contacting the reaction product of step (A) with conventional chemical reagents to reduce the concentrations of the organic products of the reaction in step (B) to environmentally acceptable levels. Urea or sulfamic acid are preferred, especially sulfamic acid, and step (C) is not necessary or performed. 16 figs.

  4. Development of Acetic Acid Removal Technology for the UREX+Process

    International Nuclear Information System (INIS)

    Counce, Robert M.; Watson, Jack S.

    2009-01-01

    It is imperative that acetic acid is removed from a waste stream in the UREX+process so that nitric acid can be recycled and possible interference with downstream steps can be avoided. Acetic acid arises from acetohydrozamic acid (AHA), and is used to suppress plutonium in the first step of the UREX+process. Later, it is hydrolyzed into hydroxyl amine nitrate and acetic acid. Many common separation technologies were examined, and solvent extraction was determined to be the best choice under process conditions. Solvents already used in the UREX+ process were then tested to determine if they would be sufficient for the removal of acetic acid. The tributyl phosphage (TBP)-dodecane diluent, used in both UREX and NPEX, was determined to be a solvent system that gave sufficient distribution coefficients for acetic acid in addition to a high separation factor from nitric acid

  5. Development of Acetic Acid Removal Technology for the UREX+Process

    Energy Technology Data Exchange (ETDEWEB)

    Robert M. Counce; Jack S. Watson

    2009-06-30

    It is imperative that acetic acid is removed from a waste stream in the UREX+process so that nitric acid can be recycled and possible interference with downstreatm steps can be avoidec. Acetic acid arises from acetohydrozamic acid (AHA), and is used to suppress plutonium in the first step of the UREX+process. Later, it is hydrolyzed into hydroxyl amine nitrate and acetic acid. Many common separation technologies were examined, and solvent extraction was determined to be the best choice under process conditions. Solvents already used in the UREX+ process were then tested to determine if they would be sufficient for the removal of acetic acid. The tributyl phosphage (TBP)-dodecane diluent, used in both UREX and NPEX, was determined to be a solvent system that gave sufficient distribution coefficients for acetic acid in addition to a high separation factor from nitric acid.

  6. Removal of Acid Yellow 17 Dye by Fenton Oxidation Process

    Science.gov (United States)

    Khan, Jehangeer; Sayed, Murtaza; Ali, Fayaz; Khan, Hasan Mahmood

    2018-05-01

    In the present research work the degradation of acid yellow 17 (AY 17) by H2O2/Fe2+ was investigated. The effect of various conditions such as pH value, temperature, conc. of H2O2, Fe2+, conc. of AY 17 were studied. Additionally the scavenging effects of various anions such as Cl-, SO42-, CO32- and HCO3-, on percent degradation of AY 17 were examined. It was found that these anions decrease percent degradation as well as rate of degradation reaction. The optimum conditions were determined as [AY 17]=[Fe2+]=0.06 mM [H2O2]=0.9 mM, and pH 3.0 for 60 min of reaction time. It was found that at optimum conditions 89% degradation of AY17 was achieved. The degradation kinetics of AY17 followed pseudo-first-order reaction kinetics. Thermodynamic studies under natural conditions showed positive value of ΔH (enthalpy) which indicates the degradation process is endothermic.

  7. Process for the removal of radium from acidic solutions containing same

    Science.gov (United States)

    Scheitlin, F.M.

    The invention is a process for the removal of radium from acidic aqueous solutions. In one aspect, the invention is a process for removing radium from an inorganic-acid solution. The process comprises contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple, comparatively inexpensive, and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities throughout the United States. The invention is applicable, for example, to the recovery of /sup 226/Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings.

  8. Color removal from acid and reactive dye solutions by electrocoagulation and electrocoagulation/adsorption processes.

    Science.gov (United States)

    Bellebia, S; Kacha, S; Bouberka, Z; Bouyakoub, A Z; Derriche, Z

    2009-04-01

    In this study, electrocoagulation of Marine Blue Erionyl MR (acid dye) and electrocoagulation followed by adsorption of Brilliant Blue Levafix E-BRA (reactive dye) from aqueous solutions were investigated, using aluminum electrodes and granular activated carbon (GAC). In the electrocoagulation and adsorption of dyestuff solutions, the effects of current density, loading charge, pH, conductivity, stirring velocity, contact time, and GAC concentration were examined. The optimum conditions for the electrocoagulation process were identified as loading charges 7.46 and 1.49 F/m3, for a maximum abatement of 200 mg/L reactive and acid dye, respectively. The residual reactive dye concentration was completely removed with 700 mg/L GAC. The results of this investigation provide important data for the development of a combined process to remove significant concentrations of recalcitrant dyes from water, using moderate activated carbon energy and aluminum consumption, and thereby lowering the cost of treatment.

  9. Removal of Free Fatty Acid from Plant Oil by the Adsorption Process

    Science.gov (United States)

    Chung, Tsair-Wang; Wu, Yi-Ling; Hsu, Shih-Hong

    2018-05-01

    The food oil refinery process for deacidification is ususally conducted by the neutralization after degumming. In this study, commercialized resins will be used as adsorbents to remove the free fatty acid (FFA) in food oil without using any solvent. Applying this environmental friendly green process, the energy efficiency will be increased and the waste water will be reduced compared to the traditional process. The selected adsorbent can be reused which may reduce the process cost. Instead of using alkali neutralization, the proposed process may reduce the concern of food oil security. The commercial resins A26OH and IRA900Cl were compared as adsorbents to remove the FFA in deacidification for refinery of food oil without adding any alkali chemicals. This process will be conducted to remove the FFA form peanut oil in this study. Besides, this study will get the adsorption isotherms for one of the better sorbents of A26OH or IRA900Cl to remove FFA from peanut oil under 25, 35, and 45°C. The Langmuir and Freundlich isotherm models were compared to fit the experimental data. The obtained isotherm data is important for the adsorption system design.

  10. Process for the removal of radium from acidic solutions containing same

    International Nuclear Information System (INIS)

    Scheitlin, F.M.

    1984-01-01

    Radium is removed from an inorganic-acid solution contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities. The invention is applicable, for example, to the recovery of 226 Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings, and thus contain thorium and uranium. The contaminated fly ash may be incorporated in a suitable matrix and stored, and the residual solutions processed to separate uranium and thorium. (author)

  11. Process for the removal of acid forming gases from exhaust gases and production of phosphoric acid

    Science.gov (United States)

    Chang, Shih-Ger; Liu, David K.

    1992-01-01

    Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorous preferably in a wet scrubber. The addition of yellow phosphorous in the system induces the production of O.sub.3 which subsequently oxidizes NO to NO.sub.2. The resulting NO.sub.2 dissolves readily and can be reduced to form ammonium ions by dissolved SO.sub.2 under appropriate conditions. In a 20 acfm system, yellow phosphorous is oxidized to yield P.sub.2 O.sub.5 which picks up water to form H.sub.3 PO.sub.4 mists and can be collected as a valuable product. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, better than 90% of SO.sub.2 and NO in simulated flue gas can be removed. Stoichiometric ratios (P/NO) ranging between 0.6 and 1.5 were obtained.

  12. Biochemical process for the removal of uranium from acid mine drainages

    International Nuclear Information System (INIS)

    Roig, M.G.; Manzano, T.; Diaz, M.

    1997-01-01

    A biochemical process has been assessed with a view to removing heavy metals from acid mine drainages in which the metal cation removed is accumulated in situ as insoluble metal phosphate on the surface of Citrobacter N 14 cells (Roig et al., 1995). The localized presence of inorganic phosphate (P i ) is brought about via the hydrolysis of a ''donor'' organic phosphate added to the solution of metals with precipitation as MHPO 4 bound to the cells. The present work explores the potential of immobilized Citrobacter biomass for the recovery of uranium from the acid drainage waters of the ''Faith'' mine exploited by ENUSA (Ciudad Rodrigo, Salamanca). A physicochemical characterization of the acid waste-water from ENUSA was carried out and flow injection analysis methods for the determination of uranium and P i in such water were developed and improved. The efficiencies of chemical precipitation (by the addition of P i to the acid water) with regard to bioinsolubilization (supplementing the water with an organic phosphate that is (later) hydrolysed to P i ) were investigated and compared. Additionally, the efficiency of chemical and biochemical precipitation as phosphates of uranium present in ENUSA acid drainage water were assessed. Furthermore, the relative importance of chemical precipitation (by the addition of P i to the acid water) with regard to bioinsolubilization (supplementing the water with an organic phosphate that is (later) hydrolysed to P i plus alcohol) was established. To do so, a series of mass balances for chemical precipitation and for bioinsolubilization of the metal phosphate was performed. Once the efficiency of the bioprocess as regards the removal of uranium when glycerol-2-phosphate is used as a substrate had been determined, a major question was forthcoming: the search for an efficient and much more economical substrate for the process. In this sense, sodium tripolyphosphate, one of the main components of many formulations of commercial

  13. Kinetic evaluation and process performance of a fixed film bioreactor removing phthalic acid and dimethyl phthalate.

    Science.gov (United States)

    Pirsaheb, Meghdad; Mesdaghinia, Ali-Reza; Shahtaheri, Seyed Jamaleddin; Zinatizadeh, Ali Akbar

    2009-08-15

    Phthalate esters are toxic organic contaminants which can enter into the environment through various industrial processes. In this study, a 6-liter fixed film bioreactor was used to examine biodegradation of phthalic acid (PA) and dimethyl phthalate (DMP) in synthetic wastewater. Effect on the process of two operating factors, namely hydraulic retention time (HRT) (at four levels ranging between 6 and 48 h) and initial phthalate concentrations (at six levels ranging from 10mg to 500 mg/l), was investigated. The process was stable at all operating conditions, except for the condition with influent PA and DMP of 500 mg/l and HRT of 6h. More than 95% removal efficiency was achieved for the conditions with HRT longer than 10h. Remarkable amount of DMP (398 mg/kg of sludge) was adsorbed on the biomass due to its higher hydrophobicity compared to PA (171 mg/kg). The kinetic parameters (mu(m,)K(s), Y and K(d)) were determined and compared for both substrates, PA and DMP.

  14. New concepts of microbial treatment processes for the nitrogen removal: effect of protein and amino acids degradation.

    Science.gov (United States)

    González-Martínez, Alejandro; Calderón, Kadiya; González-López, Jesús

    2016-05-01

    High concentrations of proteins and amino acids can be found in wastewater and wastewater stream produced in anaerobic digesters, having shown that amino acids could persist over different managements for nitrogen removal affecting the nitrogen removal processes. Nitrogen removal is completely necessary because of their implications and the significant adverse environmental impact of ammonium such as eutrophication and toxicity to aquatic life on the receiving bodies. In the last decade, the treatment of effluents with high ammonium concentration through anammox-based bioprocesses has been enhanced because these biotechnologies are cheaper and more environmentally friendly than conventional technologies. However, it has been shown that the presence of important amounts of proteins and amino acids in the effluents seriously affects the microbial autotrophic consortia leading to important losses in terms of ammonium oxidation efficiency. Particularly the presence of sulfur amino acids such as methionine and cysteine has been reported to drastically decrease the autotrophic denitrification processes as well as affect the microbial community structure promoting the decline of ammonium oxidizing bacteria in favor of other phylotypes. In this context we discuss that new biotechnological processes that improve the degradation of protein and amino acids must be considered as a priority to increase the performance of the autotrophic denitrification biotechnologies.

  15. Humic Acid Removal from Aqueous Environments by Electrocoagulation Process Using Iron Electrodes

    Directory of Open Access Journals (Sweden)

    Edris Bazrafshan

    2012-01-01

    Full Text Available At present study the performance of electrocoagulation process using iron electrodes sacrificial anode has been investigated for removal of HA from artificial aqueous solution. The experiments were performed in a bipolar batch reactor with four iron electrode connected in parallel. Several working parameters, such as initial pH (3, 5, 7, and 9, electrical conductivity (50 V and reaction time were studied in an attempt to achieve the highest removal capacity. Solutions of HA with concentration equal 20 mg L-1 were prepared. To follow the progress of the treatment, samples of 10 ml were taken at 15, 30, 45, 60, and 75 min interval. Finally HA concentration was measured by UV absorbance at 254 nm (UV254 and TOC concentration was measured by TOC Analyser. The maximum efficiency of HA removal which was obtained in voltage of 50 V, reaction time of 75 min, initial concentration 20 mg L-1, conductivity 3000 µS/Cm and pH 5, is equal to 92.69%. But for natural water samples at the same optimum condition removal efficiency was low (68.8 %. It can be concluded that the electrocoagulation process has the potential to be utilized for cost-effective removal of HA from aqueous environments.

  16. Application of advanced oxidation processes for removing salicylic acid from synthetic wastewaters

    Institute of Scientific and Technical Information of China (English)

    Djalma; Ribeiro; da; Silva; Carlos; A.Martinez-Huítle

    2010-01-01

    In this study,advanced oxidation processes(AOPs) such as anodic oxidation(AO),UV/H_2O_2 and Fenton processes(FP) were investigated for the degradation of salicylic acid(SA) in lab-scale experiments.Boron-doped diamond(BDD) film electrodes using Ta as substrates were employed for AO of SA.In the case of FP and UV/H_2O_2,most favorable experimental conditions were determined for each process and these were used for comparing with AO process.The study showed that the FP was the most effective process under ...

  17. Isotherm, kinetic and thermodynamics study of humic acid removal process from aquatic environment by chitosan nano particle

    Directory of Open Access Journals (Sweden)

    Maryam Ghafoori

    2016-09-01

    Full Text Available Background and Aim: Humic substances include natural organic polyelectrolyte materials that formed most of the dissolved organic carbon in aquatic environments. Reaction between humic substances and chlorine leading to formation of disinfection byproducts (DBPs those are toxic, carcinogenic and mutagenic. The aim of this study was investigation of isotherms, kinetics and thermodynamics of humic acid removal process by nano chitosan from aquatic environment. Materials and Methods: This practical research was an experimental study that performed in a batch system. The effect of various parameters such as pH, humic acid concentration, contact time, adsorbent dosage, isotherms, thermodynamics and Kinetics of humic acid adsorption process were investigated. Humic acid concentration measured using spectrophotometer at wave length of 254 nm. Results: The results of this research showed that maximum adsorption capacity of nanochitosan that fall out in concentration of 50 mg/l and contact time of 90 minutes was 52.34 mg/g. Also, the maximum adsorption was observed in pH = 4 and adsorbent dosage 0.02 g. Laboratory data show that adsorption of humic acid by nanochitosan follow the Langmuir isotherm model. According to result of thermodynamic study, entropy changes (ΔS was equal to 2.24 J/mol°k, enthalpy changes (ΔH was equal to 870 kJ/mol and Gibbs free energy (ΔG was negative that represent the adsorption process is spontaneous and endothermic. The kinetics of adsorption has a good compliant with pseudo second order model. Conclusion: Regarding to results of this study, nano chitosan can be suggested as a good adsorbent for the removal of humic acids from aqueous solutions.

  18. Process for the removal of acid forming gases from exhaust gases

    Science.gov (United States)

    Chang, S.G.; Liu, D.K.

    1992-11-17

    Exhaust gases are treated to remove NO or NO[sub x] and SO[sub 2] by contacting the gases with an aqueous emulsion or suspension of yellow phosphorus preferably in a wet scrubber. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50 C is attractive. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO[sub x] and SO[sub 2], alkalis that are used for flue gas desulfurization are preferred. With this process, 100% of the by-products created are usable, and close to 100% of the NO or NO[sub x] and SO[sub 2] can be removed in an economic fashion. 9 figs.

  19. Monopolar Electro-Coagulation Process for Azo Dye C.I. Acid Red 18 Removal from Aqueous Solutions

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    Ghasem Azarian

    2014-12-01

    Full Text Available The discharge of wastewaters containing an untreated dye results in aesthetic problems and an increase in gases solubility, which causes light transmission inhibition into water bodies. In spite of advantages of physicochemical and biological methods, these processes produce huge amounts of sludge, toxic by-products and require several oxidant chemicals. By contrast, electrochemical processes because of their high versatility, high efficiency and eco-friendly properties are more acceptable. In the present study, the removal of azo dye Acid Red 18 and chemical oxygen demand (COD from synthetic wastewater by monopolar (EC process was investigated and key parameters such as operating time, current density (CD, initial pH and energy, and electrode consumption were optimized. It was found that the process had a very good efficiency in the removal of both COD and color; for the iron electrode, the maximum amounts of color and COD removal were 99.5% and 59.0%, respectively. An operating time of 45 min, pH of 7 and CD of 1.2 mA/cm2 was selected as the optimized condition. The optimization of variables is extremely crucial as it results in a decrease in costs, energy and electrode consumption. Overall, the iron electrode used less energy than the aluminum electrode and was more acceptable for use in this process due to economical reasons. The findings of UV/vis spectra illustrated that the structures of this dye were removed by the process. In comparison with traditional methods such as aerobic and anaerobic systems, the EC process is a suitable alternative for the treatment of wastewaters containing dye pollutants.

  20. Counter-current acid leaching process for the removal of Cu, Pb, Sb and Zn from shooting range soil.

    Science.gov (United States)

    Lafond, Stéphanie; Blais, Jean-François; Mercier, Guy; Martel, Richard

    2013-01-01

    This research explores the performance of a counter-current leaching process (CCLP) for Cu, Pb, Sb and Zn extraction in a polluted shooting range soil. The initial metal concentrations in the soil were 1790 mg Cu/kg, 48,300 mg Pb/kg, 840 mg Sb/kg and 368 mg Zn/kg. The leaching process consisted of five one-hour acid leaching steps, which used 1 M H2SO4 + 4 M NaCl (20 degrees C, soil suspension = 100 g/L) followed by two water rinsing steps. Ten counter-current remediation cycles were completed and the average metal removal yields were 98.3 +/- 0.3% of Cu, 99.5 +/- 0.1% of Pb, 75.5 +/- 5.1% of Sb and 29.1 +/- 27.2% of Zn. The quality of metal leaching did not deteriorate throughout the 10 remediation cycles completed for this study. The CCLP reduced acid and salt use by approximately 68% and reduced water consumption by approximately 60%, exceeding reductions achieved by a standard acid leaching process.

  1. Removal of Acid Red 14 from Contaminated Water Using UV/S2O82- Advanced Oxidation Process

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    Mohammad Hossein Rasoulifard

    2012-10-01

    Full Text Available The present study investigates the degradation of Acid Red 14 (AR14, commonly used as a textile dye in aqueous medium through the oxidation process by UV /S2O82- under a set of variables concentration of S2O82-, Ag+, AR14 and temperature. Commonly Ag+, heat and UV light can excite S2O82− to sulfate radical form (SO4−•, a stronger oxidant (E0 = 2.60 V than S2O82−, to enhance significantly the oxidation of contaminants. Also the changes in the absorption spectra of AR14 solutions during the photoxidation process showed that decrease of absorption peak of the dye at λmax = 514 nm indicates a rapid degradation of the azo dye. The results of this study suggest that the oxidative treatment of AR14 by peroxydisulfate with UV is a viable option for removal of the textile dyes from effluents.

  2. The Investigation of Electron Beam Catalytical Oxidation Process Efficiency with Potassium Persulfate in Removal Humic Acid from Aqueous Solutions

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    MT Ghaneian

    2015-05-01

    Results: Based on the results, changes in pH had little effect on the Humic acid removal efficiency. The average, with increasing of pH from 4 to 10, the removal efficiency of humic acid from 72.59% to 73.36% increased, respectively. The results showed that increasing of the dose from 1 to 15 kGy, humic acid removal efficiency increases. Based on results by increasing of persulfate concentration, the removal efficiency increased so that with increasing of concentration of potassium persulfate from 0.1 to 0.5 mmol/100cc, removal efficiency from 69.43% to 83.82% was increased. Kinetic experiments showed that the decomposition of humic acid by electron beam radiation followed the second-order kinetic. Conclusion: The data from this study showed that the aqueous solution containing acid Humic is decomposed effectively by electron beams irradiation. Addition of potassium persulfate can be have significant improvements in removal efficiency of humic acid in the presence of electron beam.

  3. Impact of treatment processes on the removal of perfluoroalkyl acids from the drinking water production chain

    NARCIS (Netherlands)

    Eschauzier, C.; Beerendonk, E.; Scholte-Veenendaal, P.; de Voogt, P.

    2012-01-01

    The behavior of polyfluoralkyl acids (PFAAs) from intake (raw source water) to finished drinking water was assessed by taking samples from influent and effluent of the several treatment steps used in a drinking water production chain. These consisted of intake, coagulation, rapid sand filtration,

  4. ARSENIC REMOVAL BY IRON REMOVAL PROCESSES

    Science.gov (United States)

    Presentation will discuss the removal of arsenic from drinking water using iron removal processes that include oxidation/filtration and the manganese greensand processes. Presentation includes results of U.S. EPA field studies conducted in Michigan and Ohio on existing iron remo...

  5. Nitrate removal properties of solid-phase denitrification processes using acid-blended poly(L-lactic acid) as the sole substrate

    International Nuclear Information System (INIS)

    Yamada, T; Matsuoka, H; Sun, J; Tsuji, H; Hiraishi, A; Yoshikawa, S

    2013-01-01

    The large amount of waste that is discharged along with the diffusion of poly(L-lactic acid) (PLLA) articles in use is persistent concern. Previously, we studied solid-phase denitrification (SPD) processes using PLLA to establish an effective re-use of PLLA waste. We found that PLLA with a weight-average molecular weight (M w ) of approximately 10,000 was suitable for SPD processes; however, the recycling of PLLA waste consumes a high energy. A new PLLA plastic including 5% poly(ethylene oxalate) (PEOxPLLA) as a blend material has attracted attention because recycling of PEOxPLLA consumes less electricity than that of PLLA. In this study, our main objectives were to evaluate whether PEOxPLLA can be used for SPD processes by changing its M w and to investigate the bioavailability for denitrification of hydrolysates released from PEOxPLLA. The predicted hydrolysates, including oxalic acid, ethylene glycol, and lactate, are abiotically released, leading to different biological nitrate removal rates. Consequently, the nitrate removal rate of PEOxPLLA ranged from 0.9–4.1 mg-NO 3 − -N·g-MLSS·h −1 by changing the M w in the range of 8,500–238,000. In culture-dependent approaches, denitrifying bacteria using each substrate as an electron donor are found in activated sludge, suggesting that all hydrolysates functioned in the SPD processes using PEOxPLLA.

  6. Removal of Mefenamic acid from aqueous solutions by oxidative process: Optimization through experimental design and HPLC/UV analysis.

    Science.gov (United States)

    Colombo, Renata; Ferreira, Tanare C R; Ferreira, Renato A; Lanza, Marcos R V

    2016-02-01

    Mefenamic acid (MEF) is a non-steroidal anti-inflammatory drug indicated for relief of mild to moderate pain, and for the treatment of primary dysmenorrhea. The presence of MEF in raw and sewage waters has been detected worldwide at concentrations exceeding the predicted no-effect concentration. In this study, using experimental designs, different oxidative processes (H2O2, H2O2/UV, fenton and Photo-fenton) were simultaneously evaluated for MEF degradation efficiency. The influence and interaction effects of the most important variables in the oxidative process (concentration and addition mode of hydrogen peroxide, concentration and type of catalyst, pH, reaction period and presence/absence of light) were investigated. The parameters were determined based on the maximum efficiency to save time and minimize the consumption of reagents. According to the results, the photo-Fenton process is the best procedure to remove the drug from water. A reaction mixture containing 1.005 mmol L(-1) of ferrioxalate and 17.5 mmol L(-1) of hydrogen peroxide, added at the initial reaction period, pH of 6.1 and 60 min of degradation indicated the most efficient degradation, promoting 95% of MEF removal. The development and validation of a rapid and efficient qualitative and quantitative HPLC/UV methodology for detecting this pollutant in aqueous solution is also reported. The method can be applied in water quality control that is generated and/or treated in municipal or industrial wastewater treatment plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Removal of Anabaena flos-aquae in water treatment process using Moringa oleifera and assessment of fatty acid profile of generated sludge.

    Science.gov (United States)

    Moreti, Livia O R; Coldebella, Priscila Ferri; Camacho, Franciele P; Carvalho Bongiovani, Milene; Pereira de Souza, Aloisio Henrique; Kirie Gohara, Aline; Matsushita, Makoto; Fernandes Silva, Marcela; Nishi, Letícia; Bergamasco, Rosângela

    2016-01-01

    This study aimed to evaluate the efficiency of the coagulation/flocculation/dissolved air flotation (C/F/DAF) process using the coagulant Moringa oleifera (MO) seed powder, and to analyse the profile of fatty acids present in the generated sludge after treatment. For the tests, deionized water artificially contaminated with cell cultures of Anabaena flos-aquae was used, with a cell density in the order of 10(4) cells mL(-1). C/F/DAF tests were conducted using 'Flotest' equipment. For fatty acid profile analyses, a gas chromatograph equipped with a flame ionization detector was used. It was seen that the optimal dosage (100 mg L(-1)) of MO used in the C/F/DAF process was efficient at removing nearly all A. flos-aquae cells (96.4%). The sludge obtained after treatment contained oleic acid (61.7%) and palmitic acid (10.8%). Thus, a water treatment process using C/F/DAF linked to integral MO powder seed was found to be efficient in removing cells of cyanobacteria, and produced a sludge rich in oleic acid that is a precursor favourable for obtaining quality biodiesel, thus becoming an alternative application for the recycling of such biomass.

  8. Demonstration of the efficiency and robustness of an acid leaching process to remove metals from various CCA-treated wood samples.

    Science.gov (United States)

    Coudert, Lucie; Blais, Jean-François; Mercier, Guy; Cooper, Paul; Janin, Amélie; Gastonguay, Louis

    2014-01-01

    In recent years, an efficient and economically attractive leaching process has been developed to remove metals from copper-based treated wood wastes. This study explored the applicability of this leaching process using chromated copper arsenate (CCA) treated wood samples with different initial metal loading and elapsed time between wood preservation treatment and remediation. The sulfuric acid leaching process resulted in the solubilization of more than 87% of the As, 70% of the Cr, and 76% of the Cu from CCA-chips and in the solubilization of more than 96% of the As, 78% of the Cr and 91% of the Cu from CCA-sawdust. The results showed that the performance of this leaching process might be influenced by the initial metal loading of the treated wood wastes and the elapsed time between preservation treatment and remediation. The effluents generated during the leaching steps were treated by precipitation-coagulation to satisfy the regulations for effluent discharge in municipal sewers. Precipitation using ferric chloride and sodium hydroxide was highly efficient, removing more than 99% of the As, Cr, and Cu. It appears that this leaching process can be successfully applied to remove metals from different CCA-treated wood samples and then from the effluents. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: Enhanced removal of aromatic amines

    International Nuclear Information System (INIS)

    Hosseini Koupaie, E.; Alavi Moghaddam, M.R.; Hashemi, S.H.

    2011-01-01

    Highlights: → Biofilm process was applied as post-treatment of anaerobically degraded an azo dye. → More than 65% of the dye total metabolites was completely mineralized. → Based on HPLC analysis, more than 80% of 1-naphthylamine-4-sulfonate was removed. → Inhibition of biofilm growth was increased with increasing the initial dye concentration. → Considerable porous morphology was observed in the SEM photographs of the biofilm. - Abstract: The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

  10. Pyrolusite Process® to remove acid mine drainage contaminants from Kimble Creek in Ohio: A pilot study

    Science.gov (United States)

    Shiv Hiremath; Kirsten Lehtoma; Mike Nicklow; Gary. Willison

    2013-01-01

    The Kimble Creek abandoned coal mine site, located on Wayne National Forest in southeastern Ohio, is among several abandoned coal mine sites that have been responsible for the acid mine drainage (AMD) polluting ground and surface water. Materials released by AMD include iron, aluminum, manganese, other hazardous substances, and acidity that are harmful to aquatic life...

  11. Evaluation of biochar-ultrafiltration membrane processes for humic acid removal under various hydrodynamic, pH, ionic strength, and pressure conditions.

    Science.gov (United States)

    Shankar, Vaibhavi; Heo, Jiyong; Al-Hamadani, Yasir A J; Park, Chang Min; Chu, Kyoung Hoon; Yoon, Yeomin

    2017-07-15

    The performance of an ultrafiltration (UF)-biochar process was evaluated in comparison with a UF membrane process for the removal of humic acid (HA). Bench-scale UF experiments were conducted to study the rejection and flux trends under various hydrodynamic, pH, ionic strength, and pressure conditions. The resistance-in-series model was used to evaluate the processes and it showed that unlike stirred conditions, where low fouling resistance was observed (28.7 × 10 12  m -1 to 32.5 × 10 12  m -1 ), higher values and comparable trends were obtained for UF-biochar and UF alone for unstirred conditions (28.7 × 10 12  m -1 to 32.5 × 10 12  m -1 ). Thus, the processes were further evaluated under unstirred conditions. Additionally, total fouling resistance was decreased in the presence of biochar by 6%, indicating that HA adsorption by biochar could diminish adsorption fouling on the UF membrane and thus improve the efficiency of the UF-biochar process. The rejection trends of UF-biochar and UF alone were similar in most cases, whereas UF-biochar showed a noticeable increase in flux of around 18-25% under various experimental conditions due to reduced membrane fouling. Three-cycle filtration tests further demonstrated that UF-biochar showed better membrane recovery and antifouling capability by showing more HA rejection (3-5%) than UF membrane alone with each subsequent cycle of filtration. As a result of these findings, the UF-biochar process may potentially prove be a viable treatment option for the removal of HA from water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Analysis of Sustainable Technologies for Acid Gas Removal

    OpenAIRE

    Dal Pozzo, Alessandro

    2017-01-01

    Acid gases, such as sulphur dioxide and hydrogen halides and – in a broad sense – carbon dioxide, are typical pollutants generated by combustion processes. Their removal by means of solid sorbents represent an efficient and cost-effective approach in dry acid gas treatment systems for waste incineration flue gas, while for CO2 capture the process is exploratively studied as a promising alternative to amine scrubbing. The present study addressed both aspects. In waste incineration flue gas ...

  13. Americium removal from nitric acid waste streams

    International Nuclear Information System (INIS)

    Muscatello, A.C.; Navratil, J.D.

    1986-01-01

    Separations research at the Rocky Flats Plant (RFP) has found ways to significantly improve americium removal from nitric acid (7M) waste streams generated by plutonium purification operations. Partial neutralization of the acid waste followed by solid supported liquid membranes (SLM) are useful in transferring and concentrating americium from nitrate solutions. Specifically, DHDECMP (dihexyl-N,N-diethylcarbamoylmethylphosphonate) supported on Accurel polypropylene hollow fibers assembled in modular form transfers >95% of the americium from high nitrate (6.9M), low acid (0.1M) feeds into 0.25M oxalic acid stripping solution. Maximum permeabilities were observed to be 0.001 cm/sec, consistent with typical values for other systems. The feed:strip volume ratio shows an inverse relationship to the fraction of metal ion transferred. Cation exchangers may be used to concentrate americium from the strip solution. Furthermore, O0D (iB)CMPO (or CMPO) (octylphenyl-N-N-diisobutylcarbamoylmethylphosphine oxide) has been tested in an extraction chromatography mode. Preliminary results show CMPO to be effective in removing americium if the feed is neutralized to 1.0M acidity and iron(III) is complexed with 0.20M oxalic acid. 3 figs

  14. Removal of fluoride from aqueous nitric acid

    International Nuclear Information System (INIS)

    Pruett, D.J.; Howerton, W.B.; Mailen, J.C.

    1981-06-01

    Several methods for removing fluoride from aqueous nitric acid were investigated and compared with the frequently used aluminum nitrate-calcium nitrate (Ca 2+ -Al 3+ ) chemical trap-distillation system. Zirconium oxynitrate solutions were found to be superior in preventing volatilization of fluoride during distillation of the nitric acid, producing decontamination factors (DFs) on the order of 2 x 10 3 (vs approx. 500 for the Ca 2+ -Al 3+ system). Several other metal nitrate systems were tested, but they were less effective. Alumina and zirconia columns proved highly effective in removing HF from HF-HNO 3 vapors distilled through the columns; fluoride DFs on the order of 10 6 and 10 4 , respectively, were obtained. A silica gel column was very effective in adsorbing HF from HF-HNO 3 solutions, producing a fluoride DF of approx. 10 4

  15. A secondary fuel removal process: plasma processing

    Energy Technology Data Exchange (ETDEWEB)

    Min, J Y; Kim, Y S [Hanyang Univ., Seoul (Korea, Republic of); Bae, K K; Yang, M S [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-07-01

    Plasma etching process of UO{sub 2} by using fluorine containing gas plasma is studied as a secondary fuel removal process for DUPIC (Direct Use of PWR spent fuel Into Candu) process which is taken into consideration for potential future fuel cycle in Korea. CF{sub 4}/O{sub 2} gas mixture is chosen for reactant gas and the etching rates of UO{sub 2} by the gas plasma are investigated as functions of CF{sub 4}/O{sub 2} ratio, plasma power, substrate temperature, and plasma gas pressure. It is found that the optimum CF{sub 4}/O{sub 2} ratio is around 4:1 at all temperatures up to 400 deg C and the etching rate increases with increasing r.f. power and substrate temperature. Under 150W r.f. power the etching rate reaches 1100 monolayers/min at 400 deg C, which is equivalent to about 0.5mm/min. (author).

  16. Influence of cathode on the electro-generation of peroxydisulfuric acid oxidant and its application for effective removal of SO_2 by room temperature electro-scrubbing process

    International Nuclear Information System (INIS)

    Balaji, Subramanian; Muthuraman, Govindan; Moon, Il Shik

    2015-01-01

    Highlights: • Electrolytic production of peroxydisulfuric acid (PDSA) with BDD anode. • PDSA yield enhanced by proper selection of cathode material. • Electro-scrubbing of SO_2 in presence of PDSA monitored by online FTIR analyzer. • 100% SO_2 removal was achieved for 25 ppm and 50 ppm in less than 10 min. - Abstract: Peroxydisulfuric acid oxidant (H_2S_2O_8) was electro-generated using boron doped diamond (BDD) anode in an undivided electrolytic cell under the optimized conditions and used for the oxidative removal of gaseous SO_2. The influence of the nature of cathode material on the formation yield of H_2S_2O_8 was investigated with Ti, Pt, Zr and DSA electrodes in a flow type electrolytic cell under batch recirculation mode. Among the various cathodes employed Ti exhibited a good performance and the formation yield was nearly doubled (0.19 M) compared to the reported value of 0.07 M. The optimization of electrode area ratio between the anode and cathode brought out the fact that for nearly 8 times smaller Ti cathode (8.75:1) the achieved yield was ∼65% higher than the 1:1 ratio of anode and cathode. The highest concentration of 6.8% (0.48 M) H_2S_2O_8 was seen for 35 cm"2 BDD anode with 4 cm"2 Ti at 20 °C with the measured redox potential value of +1200 mV. The oxidative removal of SO_2 in an electro-scrubbing column attached to the online production of peroxydisulfuric acid under the optimized conditions of cell parameters shows that SO_2 removal efficiency was nearly 100% for 25 and 50 ppm inlet concentrations and 96% for 100 ppm at the room temperature of 25 °C.

  17. Acidity removal from Lusatian mining lakes through eutrophication

    Energy Technology Data Exchange (ETDEWEB)

    Fyson, A.; Nixdorf, B.; Steinberg, C.F.W. [Brandenburg University of Technology, Cottbus (Germany)

    2001-07-01

    The flooded, disused lignite pits of Lusatia in north-eastern Germany are characterised by low pH (2 - 3.5) and high concentrations of iron which contribute to high acidity. Removal of acidity from these lakes using low-cost, environmentally acceptable technologies is being investigated. One option is the enhancement of biologically mediated, alkalinity generating processes, through controlled eutrophication to sustainably increase nutrient cycling and carbon inputs. Although the primary production of these waters is potentially high and diverse algae grow in these lakes, the growth of autotrophic organisms is usually limited by extremely low concentrations of P and inorganic C. Theoretical considerations and laboratory mesocosm results are used to demonstrate the potential productivity of these acid waters and the direct and indirect role of controlled eutrophication in removing acidity. Such data are being used to generate self-sustaining, environmentally friendly, affordable remediation strategies to develop these lakes for recreation and wildlife. 14 refs., 1 tab.

  18. Soni-removal of nucleic acids from inclusion bodies.

    Science.gov (United States)

    Neerathilingam, Muniasamy; Mysore, Sumukh; Gandham, Sai Hari A

    2014-05-23

    Inclusion bodies (IBs) are commonly formed in Escherichia coli due to over expression of recombinant proteins in non-native state. Isolation, denaturation and refolding of these IBs is generally performed to obtain functional protein. However, during this process IBs tend to form non-specific interactions with sheared nucleic acids from the genome, thus getting carried over into downstream processes. This may hinder the refolding of IBs into their native state. To circumvent this, we demonstrate a methodology termed soni-removal which involves disruption of nucleic acid-inclusion body interaction using sonication; followed by solvent based separation. As opposed to conventional techniques that use enzymes and column-based separations, soni-removal is a cost effective alternative for complete elimination of buried and/or strongly bound short nucleic acid contaminants from IBs. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Tetracycline removal and effect on the formation and degradation of extracellular polymeric substances and volatile fatty acids in the process of hydrogen fermentation.

    Science.gov (United States)

    Hou, Guangying; Hao, Xiaoyan; Zhang, Rui; Wang, Jing; Liu, Rutao; Liu, Chunguang

    2016-07-01

    Many research indicate antibiotics show adverse effect on methane fermentation, while few research focus on their effect on hydrogen fermentation. The present study aimed to gain insight of the effect of antibiotics on hydrogen fermentation with waste sludge and corn straw as substrate. For this purpose, tetracycline, as a model, was investigated with regard to tetracycline removal, hydrogen production, interaction with extracellular polymeric substances (EPSs) of substrate and volatile fatty acids (VFAs) on concentration and composition. Results show that tetracycline could be removed efficiently by hydrogen fermentation, and relative low-dose tetracycline (200mg/l) exposure affects little on hydrogen production. While tetracycline exposure could change hydrogen fermentation from butyric acid-type to propionic acid-type depending on tetracycline level. Based upon three-dimensional excitation-emission matrix fluorescence spectroscopy and UV-vis tetracycline changed the component and content of EPSs, and static quenching was the main mechanism between EPSs with tetracycline. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Acid Gas Removal from Natural Gas with Alkanolamines

    DEFF Research Database (Denmark)

    Sadegh, Negar

    commercially for the removal of acid gas impurities from natural gas. Alkanolamines, simple combinations of alcohols and ammonia, are the most commonly used category of chemical solvents for acid gas capture. This Ph.D. project is aboutthermodynamics of natural gas cleaning process with alkanolamines......Some 40 % of the world’s remaining gas reserves are sour or acid, containing large quantities of CO2 and H2S and other sulfur compounds. Many large oil and gas fields have more than 10 mole % CO2 and H2S content. In the gas processing industry absorption with chemical solvents has been used...... pressure on acid gas solubility was also quantitatively investigated through both experimental and modeling approaches....

  1. Arsenic removal by electrocoagulation process: Recent trends and removal mechanism.

    Science.gov (United States)

    Nidheesh, P V; Singh, T S Anantha

    2017-08-01

    Arsenic contamination in drinking water is a major issue in the present world. Arsenicosis is the disease caused by the regular consumption of arsenic contaminated water, even at a lesser contaminated level. The number of arsenicosis patients is increasing day-by-day. Decontamination of arsenic from the water medium is the only one way to regulate this and the arsenic removal can be fulfilled by water treatment methods based on separation techniques. Electrocoagulation (EC) process is a promising technology for the effective removal of arsenic from aqueous solution. The present review article analyzes the performance of the EC process for arsenic removal. Electrocoagulation using various sacrificial metal anodes such as aluminium, iron, magnesium, etc. is found to be very effective for arsenic decontamination. The performances of each anode are described in detail. A special focus has been made on the mechanism behind the arsenite and arsenate removal by EC process. Main trends in the disposal methods of sludge containing arsenic are also included. Comparison of arsenic decontamination efficiencies of chemical coagulation and EC is also reported. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Preparation of activated petroleum coke for removal of naphthenic acids model compounds: Box-Behnken design optimization of KOH activation process.

    Science.gov (United States)

    Niasar, Hojatallah Seyedy; Li, Hanning; Das, Sreejon; Kasanneni, Tirumala Venkateswara Rao; Ray, Madhumita B; Xu, Chunbao Charles

    2018-04-01

    This study employed Box-Behnken design and response surface methodology to optimize activation parameters for the production of activated petroleum coke (APC) adsorbent from petroleum coke (PC) to achieve highest adsorption capacity for three model naphthenic acids. Activated petroleum coke (APC) adsorbent with a BET surface area of 1726 m 2 /g and total pore volume of 0.85 cc/g was produced at the optimum activation conditions (KOH/coke mass ratio) of 3.0, activation temperature 790 °C, and activation time 3.47 h). Effects of the activation parameters on the adsorption pefromances (adsortion capaciy and kinetics) were investigated. With the APC obtained at the optimum activation condition, the maximum adsorption capacity of 451, 362, and 320 (mg/g) was achieved for 2-naphthoic acid, diphenylacetic acid and cyclohexanepentanoic acid (CP), respectively. Although, generally APC adsorbents with a higher specific surface area and pore volume provide better adsorption capacity, the textural properties (surface areas and pore volume) are not the only parameters determining the APC adsorbents' adsorption capacity. Other parameters such as surface functionalities play effective roles on the adsorption capacity of the produced APC adsorbents for NAs. The KOH activation process, in particular the acid washing step, distinctly reduced the sulfur and metals contents in the raw PC, decreasing the leaching potential of metals from APC adsorbents during adsorption. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Engineering metal (hydr)oxide sorbents for removal of arsenate and similar weak-acid oxyanion contaminants: A critical review with emphasis on factors governing sorption processes.

    Science.gov (United States)

    Hristovski, Kiril D; Markovski, Jasmina

    2017-11-15

    To create an integrative foundation for engineering of the next generation inexpensive sorbent systems, this critical review addresses the existing knowledge gap in factor/performance relationships between weak-acid oxyanion contaminants and metal (hydr)oxide sorbents. In-depth understanding of fundamental thermodynamics and kinetics mechanisms, material fabrication, and analytical and characterization techniques, is necessary to engineer sorbent that exhibit high capacity, selectivity, stability, durability and mass transport of contaminants under a wide range of operating and water matrix conditions requirements. From the perspective of thermodynamics and kinetics, this critical review examines the factors affecting sorbent performances and analyzes the existing research to elucidate future directions aimed at developing novel sorbents for removal of weak-acid oxyanion contaminants from water. Only sorbents that allow construction of simple and inexpensive water treatment systems adapted to overcome fiscal and technological barriers burdening small communities could pave the road for providing inexpensive potable water to millions of people. Novel sorbents, which exhibit (1) poor performances in realistic operating and water matrix conditions and/or (2) do not comply with the purely driven economics factors of production scalability or cost expectations, are predestined to never be commercialized. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Process for recovering uranium from wet process phosphoric acid (III)

    International Nuclear Information System (INIS)

    Pyrih, R.Z.; Rickard, R.S.; Carrington, O.F.

    1983-01-01

    Uranium is conventionally recovered from wet-process phosphoric acid by two liquid ion exchange steps using a mixture of mono- and disubstituted phenyl esters of orthophosphoric acid (OPPA). Efficiency of the process drops as the mono-OPPA is lost preferentially to the aqueous phase. This invention provides a process for the removal of the uranium process organics (OPPA and organic solvents) from the raffinate of the first liquid ion exchange step and their return to the circuit. The process organics are removed by a combination flotation and absorption step, which results in the recovery of the organics on beads of a hydrophobic styrene polymer

  5. Experience with antimony activity removal process in Indian PHWRs

    International Nuclear Information System (INIS)

    Velmurugan, S.; Mittal, Vinit K.; Kumbhar, A.G.; Narasimhan, S.V.; Bhat, H.R.; Krishna Rao, K.S.; Upadhyay, S.K.; Jain, A.K.

    2008-01-01

    The problem of antimony (Sb) activity during decontamination was first encountered in NAPS-1 and Sb activity deposition took place during the decontamination resulting in poor decontamination factors (DF). Sb problem has been observed in PWRs and PHWRs elsewhere also. These utilities use an oxidative process involving the addition of H 2 O 2 to remove these Sb activities from the core and remove it on ion exchange resins. Experience in CANDU PHWRs indicated disappearance of H 2 O 2 in quantities higher than that observed in PWRs. This is attributed to the higher pick-up of H 2 O 2 by the magnetite/ferrites over large carbon steel surface present in the primary coolant system of PHWRs. Systematic work was carried out to understand the deposition of Sb on PHT system surfaces and a new method was evolved to remove the Sb activities from the system. This alternative reductive chemical process involve the addition of Nitrilo Tri Acetic Acid, Citric Acid and Rodine-92B and circulating the chemicals for a short period and then the Sb and other activities released from the core are removed by the mixed bed. Subsequent to the Sb removal process, the normal chemical decontamination of the system is carried out to remove 60 Co and other activities. This non-oxidizing Sb removal process was applied to NAPS-2 primary system prior to EMCCR. During this Sb removal process of NAPS-2, around 450 μCi/L activity of 124 Sb was released from the system surfaces to the formulation. Activity measurement in the samples collected and the on-line radiation field data indicated that deposition of Sb activities on system surfaces has been prevented by Rodine-92B and subsequently these activities have been removed by mixed bed IX columns. Antimony removal process worked successfully, but in the second normal decontamination process around 150 μCi/L activities came in the formulation which was not anticipated. As a result DF observed immediately after the decontamination campaign was not good

  6. A novel enzyme-based acidizing system: Matrix acidizing and drilling fluid damage removal

    Energy Technology Data Exchange (ETDEWEB)

    Harris, R.E.; McKay, D.M. [Cleansorb Limited, Surrey (United Kingdom); Moses, V. [King`s College, London (United Kingdom)

    1995-12-31

    A novel acidizing process is used to increase the permeability of carbonate rock cores in the laboratory and to remove drilling fluid damage from cores and wafers. Field results show the benefits of the technology as applied both to injector and producer wells.

  7. Process and system for removing tritium

    International Nuclear Information System (INIS)

    Ridgely, J.N.

    1976-01-01

    A process and system for removing tritium, particularly from high temperature gas cooled atomic reactors (HTGR), is disclosed. Portions of the reactor coolant, which is permeated with the pervasive tritium atom, are processed to remove the tritium. Under conditions of elevated temperature and pressure, the reactor coolant is combined with gaseous oxygen, resulting in the formation of tritiated water vapor from the tritium in the reactor coolant and the gaseous oxygen. The tritiated water vapor and the remaining gaseous oxygen are then successively removed by fractional liquefaction steps. The reactor coolant is then recirculated to the reactor

  8. Process for recovery of uranium from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Wiewiorowski, T.K.; Thornsberry, W.L. Jr.

    1978-01-01

    Process is claimed for the recovery of uranium from wet process phosphoric acid solution in which an organic extractant, containing uranium values and dissolved iron impurities and comprising a dialkylphosphoric acid and a trialkylphosphine oxide dissolved in a water immiscible organic solvent, is contacted with a substantially iron-free dilute aqueous phosphoric acid to remove said iron impurities. The removed impurities are bled from the system by feeding the resulting iron-loaded phosphoric acid to a secondary countercurrent uranium extraction operation from which they leave as part of the uranium-depleted acid raffinate. Also, process for recovering uranium in which the extractant, after it has been stripped of uranium values by aqueous ammonium carbonate, is contacted with a dilute aqueous acid selected from the group consisting of H 2 SO 4 , HCl, HNO 3 and iron-free H 3 PO 4 to improve the extraction efficiency of the organic extractant

  9. Suspended biofilm carrier and activated sludge removal of acidic pharmaceuticals

    DEFF Research Database (Denmark)

    Falås, Per; Baillon-Dhumez, Aude; Andersen, Henrik Rasmus

    2012-01-01

    Removal of seven active pharmaceutical substances (ibuprofen, ketoprofen, naproxen, diclofenac, clofibric acid, mefenamic acid, and gemfibrozil) was assessed by batch experiments, with suspended biofilm carriers and activated sludge from several full-scale wastewater treatment plants. A distinct...... and attached solids for the carriers) of diclofenac, ketoprofen, gemfibrozil, clofibric acid and mefenamic acid compared to the sludges. Among the target pharmaceuticals, only ibuprofen and naproxen showed similar removal rates per unit biomass for the sludges and biofilm carriers. In contrast...

  10. Carbon dioxide removal in gas treating processes

    International Nuclear Information System (INIS)

    Lidal, H.

    1992-06-01

    The main contribution of this work is the development of a simple and reliable modelling technique on carbon dioxide removal describing the vapor-liquid equilibria of CO 2 in aqueous alkanolamine solutions. By making use of measured pH data, the author has circumvented the problem of estimating interaction parameters, activity coefficients, and equilibrium constants in the prediction of vapor-liquid equilibria. The applicability of the model is best demonstrated on the tertiary amine system using MDEA. For this system, the VLE is accurately represented for temperatures in the range 25 to 140 o C, for CO 2 loadings from 0.001 to 1 mol/mol, and for amine molarities usually encountered in acid gas treating processes. The absorption of CO 2 into solutions containing the sterically hindered amine AMP, is also well described by the model. The equilibrium of CO 2 in mixed solvents containing a glycol (TEG,DEG) and an alkonolamine (MEA,DEA) has been measured at temperatures encountered in the absorption units. An equilibrium model has been developed for the CO 2 /TEG/MEA system for estimation of CO 2 partial pressures, covering loadings and temperatures for both absorption and desorption conditions. An important spin-off of the work described is that two new experimental set-ups have been designed and built. 154 refs., 38 figs., 22 tabs

  11. Carbon dioxide removal in gas treating processes

    Energy Technology Data Exchange (ETDEWEB)

    Lidal, H

    1992-06-01

    The main contribution of this work is the development of a simple and reliable modelling technique on carbon dioxide removal describing the vapor-liquid equilibria of CO{sub 2} in aqueous alkanolamine solutions. By making use of measured pH data, the author has circumvented the problem of estimating interaction parameters, activity coefficients, and equilibrium constants in the prediction of vapor-liquid equilibria. The applicability of the model is best demonstrated on the tertiary amine system using MDEA. For this system, the VLE is accurately represented for temperatures in the range 25 to 140{sup o}C, for CO{sub 2} loadings from 0.001 to 1 mol/mol, and for amine molarities usually encountered in acid gas treating processes. The absorption of CO{sub 2} into solutions containing the sterically hindered amine AMP, is also well described by the model. The equilibrium of CO{sub 2} in mixed solvents containing a glycol (TEG,DEG) and an alkonolamine (MEA,DEA) has been measured at temperatures encountered in the absorption units. An equilibrium model has been developed for the CO{sub 2}/TEG/MEA system for estimation of CO{sub 2} partial pressures, covering loadings and temperatures for both absorption and desorption conditions. An important spin-off of the work described is that two new experimental set-ups have been designed and built. 154 refs., 38 figs., 22 tabs.

  12. Removal of silver nanoparticles by coagulation processes

    International Nuclear Information System (INIS)

    Sun, Qian; Li, Yan; Tang, Ting; Yuan, Zhihua; Yu, Chang-Ping

    2013-01-01

    Highlights: • This study investigated the removal of AgNP suspensions by four regular coagulants. • The optimal removal efficiencies for the four coagulants were achieved at pH 7.5. • The removal efficiency of AgNPs was affected by the natural water characteristics. • TEM and XRD showed that AgNPs or silver-containing NPs were adsorbed onto the flocs. -- Abstract: Commercial use of silver nanoparticles (AgNPs) will lead to a potential route for human exposure via potable water. Coagulation followed by sedimentation, as a conventional technique in the drinking water treatment facilities, may become an important barrier to prevent human from AgNP exposures. This study investigated the removal of AgNP suspensions by four regular coagulants. In the aluminum sulfate and ferric chloride coagulation systems, the water parameters slightly affected the AgNP removal. However, in the poly aluminum chloride and polyferric sulfate coagulation systems, the optimal removal efficiencies were achieved at pH 7.5, while higher or lower of pH could reduce the AgNP removal. Besides, the increasing natural organic matter (NOM) would reduce the AgNP removal, while Ca 2+ and suspended solids concentrations would also affect the AgNP removal. In addition, results from the transmission electron microscopy and X-ray diffraction showed AgNPs or silver-containing nanoparticles were adsorbed onto the flocs. Finally, natural water samples were used to validate AgNP removal by coagulation. This study suggests that in the case of release of AgNPs into the source water, the traditional water treatment process, coagulation/sedimentation, can remove AgNPs and minimize the silver ion concentration under the well-optimized conditions

  13. Removal of sulfamic acid from plutonium sulfamate--sulfamic acid solution

    International Nuclear Information System (INIS)

    Gray, L.W.

    1978-10-01

    Plutonium metal can be readily dissolved in aqueous solutions of sulfamic acid. When the plutonium sulfamate--sulfamic acid solutions are added to normal purex process streams, the sulfamate ion is oxidized by addition of sodium nitrite. This generates sodium sulfate which must be stored as radioactive waste. When recovery of ingrown 241 Am or storage of the dissolved plutonium must be considered, the sulfamate ion poses major and undesirable precipitation problems in the process streams. The present studies show that 40 to 80% of the sulfamate present in the dissolver solutions can be removed by precipitation as sulfamic acid by the addition of concentrated nitric acid. Addition of 64% nitric acid allows precipitation of 40 to 50% of the sulfamate; addition of 72% nitric acid allows precipitation of 50 to 60% of the sulfamate. If the solutions are chilled, additional sulfamic acid will precipitate. If the solutions are chilled to -10 0 C, about 70 to 80% of the orginal sulfamic acid in the dissolver will precipitate. A single, low-volume wash of the sulfamic acid crystals with concentrated nitric acid will decontaminate the crystals to a plutonium content of 5 dis/(min-gram)

  14. Electro-coagulation-flotation process for algae removal

    International Nuclear Information System (INIS)

    Gao Shanshan; Yang Jixian; Tian Jiayu; Ma Fang; Tu Gang; Du Maoan

    2010-01-01

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density = 1 mA/cm 2 , pH = 4-7, water temperature = 18-36 deg. C, algae density = 0.55 x 10 9 -1.55 x 10 9 cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m 3 . The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view.

  15. NO/sub x/ removal facility: MON process

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Y

    1974-05-01

    A newly developed process for nitrogen oxides removal is described. The MON process, named for Mitsubishi Kizoku, Okabe of Tohoku Univ., and Nippon Kagaku, uses potassium permanganate as an oxidizing agent. Potassium permanganate in alkaline solution converts nitric oxide into nitrate and nitrogen dioxide into nitric acid. The resulting MnO/sub 2/ is easily filtered and recovered as material for the manufacturing of KMnO/sub 4/. Contrary to the conventional methods, the NO/sub x/ conversion rate increases with increasing temperature. Test results at a pilot plant showed that NO/sub x/ was reduced from 570 ppM (nitric oxide 520 ppM) to 27 ppM (mostly NO) at 97 to 98 percent conversion. Another advantage of the process is that other acidic gases such as sulfur dioxide are also removed.

  16. Biotechnology based processes for arsenic removal

    NARCIS (Netherlands)

    Huisman, J.; Olde Weghuis, M.; Gonzalez-Contreras, P.A.

    2011-01-01

    The regulations for arsenic control have become strict. Therefore, better technologies to remove arsenic from bleeds and effluents are desired. In addition, no single solution is suitable for all cases. The properties of the process streams and the storage facilities are major factors determining

  17. Sorption isotherms, kinetic and optimization process of amino acid proline based polymer nanocomposite for the removal of selected textile dyes from industrial wastewater.

    Science.gov (United States)

    Raghunath, Sharista; Anand, K; Gengan, R M; Nayunigari, Mithil Kumar; Maity, Arjun

    2016-12-01

    In this article, adsorption and kinetic studies were carried out on three textile dyes, namely Reactive Blue 222 (RB 222), Reactive Red 195 (RR 195) and Reactive Yellow 145 (RY 145). The dyes studied in a mixture were adsorbed under various conditions onto PRO-BEN, a bentonite modified with a new cationic proline polymer (l-proline-epichlorohydrin polymer). The proline polymer was characterized by 1 H NMR, Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS) and TEM. The PRO-BEN composite was characterized by FT-IR, dynamic light scattering (DLS) (zeta potential), TEM imaging, SEM/EDX and X-ray photoelectron spectroscopy (characterize the binding energy). During adsorption studies, factors involving pH, temperature, the initial concentrations of the dyes and the quantity of PRO-BEN used during adsorption were established. The results revealed that the adsorption mechanism was categorized by the Langmuir type 1 isotherm. The adsorption data followed the pseudo-second order kinetic model. The intraparticle diffusion model indicated that adsorption did not only depend on the intraparticle diffusion of the dyes. The thermodynamic parameters verified that the adsorption process was spontaneous and exothermic. The Gibbs free energy values indicated that physisorption had occurred. Successful adsorption of dyes from an industrial effluent was achieved. Desorption studies concluded that PRO-BEN desorbed the dyes better than alumina. This can thereby be viewed as a recyclable remediation material. The PRO-BEN composite could be a cost efficient alternative towards the removal of organic dyes in wastewater treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Fluoride removal performance of phosphoric acid treated lime ...

    African Journals Online (AJOL)

    Fluoride in drinking water above permissible levels is responsible for dental and skeletal fluorosis. In this study, removal of fluoride ions from water using phosphoric acid treated lime was investigated in continuous and point-of-use system operations. In the continuous column operations, fluoride removal performance was ...

  19. Process for removing mercury from aqueous solutions

    Science.gov (United States)

    Googin, John M.; Napier, John M.; Makarewicz, Mark A.; Meredith, Paul F.

    1986-01-01

    A process for removing mercury from water to a level not greater than two parts per billion wherein an anion exchange material that is insoluble in water is contacted first with a sulfide containing compound and second with a compound containing a bivalent metal ion forming an insoluble metal sulfide. To this treated exchange material is contacted water containing mercury. The water containing not more than two parts per billion of mercury is separated from the exchange material.

  20. Removing ferric ions from concentrated acid leaching solution of an uranium ore by jarosite

    International Nuclear Information System (INIS)

    Song Huanbi; Hu Yezang

    1997-01-01

    The author expounds the fundamental rules of removing ferric ions by jarosite and presents results of removing ferric ions from concentrated acid curing-trickle leaching solution of an uranium ore. It turns out that the method can be applied to uranium hydrometallurgical process effectively

  1. Wastewater centrate ammonia removal by chemisorption processes

    International Nuclear Information System (INIS)

    Barbachem, M.J.

    2002-01-01

    'Full text:' This presentation will describe the nature, scope, and findings of a third-party evaluation of a patent-protected wastewater treatment technology identified as the ThermoEnergy Ammonia Recovery Process TM (ARP). The ARP is a reversible chemisorption process using a zinc-impregnated ion exchange resin, and it is unique in that it removes/reduces the ammonia-nitrogen load in the solids processing liquor of municipal sewage treatment plants and recycles the recovered product into a pelletized ammonium salt that can be used as an agricultural fertilizer. The primary objective of the ARP evaluation was to perform well-defined field and laboratory tests to provide data on process performance. The evaluation process was overseen and coordinated by the Environmental Technology Evaluation Center (EvTEC), a program of the Civil Engineering Research Foundation (CERF), the research and technology transfer arm of the American Society of Civil Engineers (ASCE). EvTEC is a pilot program evaluating innovative environmental technologies under the US Environmental Protection Agency's (USEPA) Environmental Technology Verification (ETV) Program. A pilot scale ARP treatment facility was constructed and tested at the Oakwood Beach Water Pollution Control Plant (WPCP) in Staten Island, New York, from September through December of 1998. While operating during the 3 month period using the anaerobically digested centrate normally produced at the WPCP, the pilot study demonstrated that the ARP process was capable of removing/recovering ammonia with efficiencies ranging from 75-99+ % at influent concentrations exceeding 400 mg/L. During the pilot plant operations, forty-eight (48) complete validated runs of centrate processing were performed. The plant processed the centrate under normal day-to-day conditions at the WPCP, and no special operational considerations were given to the centrifuge operation to accommodate the ARP pilot plant. The Oakwood WPCP operated exactly the way

  2. REDUCING ARSENIC LEVELS IN DRINKING WATER DURING IRON REMOVAL PROCESSES

    Science.gov (United States)

    The presentation provides an overview of iron removal technology for the removal of arsenic from drinking water. The presentation is divided into several topic topics: Arsenic Chemistry, Treatment Selection, Treatment Options, Case Studies and Iron Removal Processes. Each topic i...

  3. Comparative study of humic acid removal and floc characteristics by electrocoagulation and chemical coagulation.

    Science.gov (United States)

    Semerjian, Lucy; Damaj, Ahmad; Salam, Darine

    2015-11-01

    The current study aims at investigating the efficiency of electrocoagulation for the removal of humic acid from contaminated waters. In parallel, conventional chemical coagulation was conducted to asses humic acid removal patterns. The effect of varying contributing parameters (matrix pH, humic acid concentration, type of electrode (aluminum vs. iron), current density, solution conductivity, and distance between electrodes) was considered to optimize the electrocoagulation process for the best attainable humic acid removal efficiencies. Optimum removals were recorded at pH of 5.0-5.5, an electrical conductivity of 3000 μS/cm at 25 °C, and an electrode distance of 1 cm for both electrode types. With aluminum electrodes, a current density of 0.05 mA/cm2 outperformed 0.1 mA/cm2 yet not higher densities, whereas a current density of 0.8 mA/cm2 was needed for iron electrodes to exhibit comparable performance. With both electrode types, higher initial humic acid concentrations were removed at a slower rate but ultimately attained almost complete removals. On the other hand, the best humic acid removals (∼90%) by chemical coagulation were achieved at 4 mg/L for both coagulants. Also, higher removals were attained at elevated initial humic acid concentrations. Humic acid removals of 90% or higher at an initial HA concentration of 40 mg/L were exhibited, yet alum performed better at the highest experimented concentration. It was evident that iron flocs were larger, denser, and more geometrical in shape compared to aluminum flocs.

  4. Process for removing polychlorinated biphenyls from soil

    Science.gov (United States)

    Hancher, C.W.; Saunders, M.B.; Googin, J.M.

    1984-11-16

    The present invention relates to a method of removing polychlorinated biphenyls from soil. The polychlorinated biphenyls are extracted from the soil by employing a liquid organic solvent dispersed in water in the ratio of about 1:3 to 3:1. The organic solvent includes such materials as short-chain hydrocarbons including kerosene or gasoline which are immiscible with water and are nonpolar. The organic solvent has a greater affinity for the PCB's than the soil so as to extract the PCB's from the soil upon contact. The organic solvent phase is separated from the suspended soil and water phase and distilled for permitting the recycle of the organic solvent phase and the concentration of the PCB's in the remaining organic phase. The present process can be satisfactorily practiced with soil containing 10 to 20% petroleum-based oils and organic fluids such as used in transformers and cutting fluids, coolants and the like which contain PCB's. The subject method provides for the removal of a sufficient concentration of PCB's from the soil to provide the soil with a level of PCB's within the guidelines of the Environmental Protection Agency.

  5. Functional consortium for denitrifying sulfide removal process.

    Science.gov (United States)

    Chen, Chuan; Ren, Nanqi; Wang, Aijie; Liu, Lihong; Lee, Duu-Jong

    2010-03-01

    Denitrifying sulfide removal (DSR) process simultaneously converts sulfide, nitrate, and chemical oxygen demand from industrial wastewaters to elemental sulfur, nitrogen gas, and carbon dioxide, respectively. This investigation utilizes a dilution-to-extinction approach at 10(-2) to 10(-6) dilutions to elucidate the correlation between the composition of the microbial community and the DSR performance. In the original suspension and in 10(-2) dilution, the strains Stenotrophomonas sp., Thauera sp., and Azoarcus sp. are the heterotrophic denitrifiers and the strains Paracoccus sp. and Pseudomonas sp. are the sulfide-oxidizing denitrifers. The 10(-4) dilution is identified as the functional consortium for the present DSR system, which comprises two functional strains, Stenotrophomonas sp. strain Paracoccus sp. At 10(-6) dilution, all DSR performance was lost. The functions of the constituent cells in the DSR granules were discussed based on data obtained using the dilution-to-extinction approach.

  6. Investigation of Removal Efficiency of Nano Sized Alumina for Removal of Acid Red 18 from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    M.H. Dehghani

    2014-08-01

    Full Text Available Background and Objectives: Acid Red 18 dye was one of the Azo colors that are used in textile and dyeing industries. These dyes are often toxic and carcinogenic to humans and the environment as pollution. This study was conducted with the aim of investigating on nano alumina efficiency for removal of Acid Red 18 dye from aqueous solutions. Materials and Methods: This study was carried out in the laboratory scales and effect of The initial concentration of dye (25 to 100 mg/l, pH solution (3, 7, 11, nano alumina concentration (0.1, 0.4, 1, 1.5 g/l and contact time in range 5 to 240 min on dye removal efficiency were evaluated. Also kinetic and isotherm models of adsorption process were evaluated. Results: The high removal efficiency was observed in pH=3, contact time=60 min and Adsorbent concentration of 0.4 g/L. The rate of color removal were 63/24, 50/84 and 20 percent respectively at pH of 3, 7 and 11 for the initial dye concentration of 25 mg/l and 0.4 g/l mass absorbent that showing with increasing pH removal efficiency is reduced. the studied dye absorption isotherm was fitted Langmuir model (R2=0.994 which was 83.33 mg/g for maximum adsorption. The results from kinetic studies showed that removal of the studied dye was best described by pseudo-second order kinetic model (r2=0.999. Conclusion: The present study shows nano alumina powder is promising adsorbent for removal of Acid Red 18 from aqueous solution.

  7. Techno-economic Analysis of Acid Gas Removal and Liquefaction for Pressurized LNG

    Science.gov (United States)

    Lee, S. H.; Seo, Y. K.; Chang, D. J.

    2018-05-01

    This study estimated the life cycle cost (LCC) of an acid gas removal and a liquefaction processes for Pressurized LNG (PLNG) production and compared the results with the cost of normal LNG production. PLNG is pressurized LNG that is liquefied at a higher pressure and temperature than normal LNG. Due to the high temperature, the energy for liquefaction is reduced. The allowable CO2 concentration in PLNG is increased up to 3 mol% when the product pressure 25 bar. An amine process with 35 wt% of diethanolamine (DEA) aqueous solution and a nitrogen expansion cycle were selected for the acid gas removal and the liquefaction processes, respectively. Two types of CO2 concentration in the feed gas were investigated to analyze their impacts on the acid gas removal unit. When the CO2 concentration was 5 mol%, the acid gas removal unit was required for both LNG and PLNG production. However, the acid gas removal unit was not necessary in PLNG when the concentration was 0.5 mol% and the pressure was higher than 15 bar. The results showed that the LCC of PLNG was reduced by almost 35% relative to that of LNG when the PLNG pressure was higher than 15 bar.

  8. Removal of an acid fume system contaminated with perchlorates located within hot cell

    International Nuclear Information System (INIS)

    Rosenberg, K.E.; Henslee, S.P.; Vroman, W.R.; Krsul, J.R.; Michelbacher, J.A.; Knighton, G.C.

    1992-09-01

    An add scrubbing system located within the confines of a highly radioactive hot cell at Argonne National Laboratory-West (ANL-W) was remotely removed. The acid scrubbing system was routinely used for the dissolution of irradiated reactor fuel samples and structural materials. Perchloric acid was one of the acids used in the dissolution process and remained in the system with its inherent risks. Personnel could not enter the hot cell to perform the dismantling of the acid scabbing system due to the high radiation field and the explosion potential associated with the perchlorates. A robot was designed and built at ANL-W and used to dismantle the system without the need for personnel entry into the hot cell. The robot was also used for size reduction of removed components and loading of the removed components into waste containers

  9. Removal of plutonium from nitric acid-oxalic acid solutions using anion exchange method

    International Nuclear Information System (INIS)

    Kasar, U.M.; Pawar, S.M.; Joshi, A.R.

    1999-01-01

    An anion exchange method using Amberlyst A-26 (MP) resin was developed for removal of Pu from nitric acid-oxalic acid solutions without destroying oxalate. The method consists of sorption of Pu(IV) on Amberlyst A-26, a macroporous anion exchange resin, from nitric acid-oxalic acid medium in the presence of Al(NO 3 ) 3 . Pu(IV) breakthrough capacity of Amberlyst A-26 using synthetic feed solution was determined. (author)

  10. Process for selected gas oxide removal by radiofrequency catalysts

    Science.gov (United States)

    Cha, Chang Y.

    1993-01-01

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO.sub.2 and NO.sub.x.

  11. Clofibric acid and gemfibrozil removal in membrane bioreactors.

    Science.gov (United States)

    Gutierrez-Macias, Tania; Nacheva, Petia Mijaylova

    2015-01-01

    The removal of two blood lipid regulators, clofibric acid (CLA) and gemfibrozil (GFZ), was evaluated using two identical aerobic membrane bioreactors with 6.5 L effective volume each. Polysulfone ultrafiltration hollow fiber membranes were submerged in the reactors. Different operating conditions were tested varying the organic load (F/M), hydraulic residence time (HRT), biomass concentration measured as total suspended solids in the mixed liquor (MLTSS) and the sludge retention time (SRT). Complete GFZ removal was obtained with F/M of 0.21-0.48 kg COD kgTSS⁻¹ d⁻¹, HRT of 4-10 hours, SRT of 10-32 d and MLTSS of 6-10 g L⁻¹. The GFZ removal can be attributed to biodegradation and there was no accumulation of the compound in the biomass. The CLA removals improved with the SRT and HRT increase and F/M decrease. Average removals of 78-79% were obtained with SRT 16-32 d, F/M of 0.21-0.34 kgCOD kgTSS⁻¹ d⁻¹, HRT of 7-10 hours and MLTSS of 6-10 g L⁻¹. Biodegradation was found to be the main removal pathway.

  12. Uranium recovery from wet process phosphoric acid

    International Nuclear Information System (INIS)

    1980-01-01

    In the field of metallurgy, specifically processes for recovering uranium from wet process phosphoric acid solution derived from the acidulation of uraniferous phosphate ores, problems of imbalance of ion exchange agents, contamination of recycled phosphoric acid with process organics and oxidizing agents, and loss and contamination of uranium product, are solved by removing organics from the raffinate after ion exchange conversion of uranium to uranous form and recovery thereof by ion exchange, and returning organics to the circuit to balance mono and disubstituted ester ion exchange agents; then oxidatively stripping uranium from the agent using hydrogen peroxide; then after ion exchange recovery of uranyl and scrubbing, stripping with sodium carbonate and acidifying the strip solution and using some of it for the scrubbing; regenerating the sodium loaded agent and recycling it to the uranous recovery step. Economic recovery of uranium as a by-product of phosphate fertilizer production is effected. (author)

  13. Ion exchange system design for removal of heavy metals from acid mine drainage wastewater

    Directory of Open Access Journals (Sweden)

    R. S. Sapkal

    2010-11-01

    Full Text Available This paper discusses the methodology used to determine the optimal ion-exchange column size to process all separate batchesof feeds from acid mine drainage wastewater.The optimal design ensures the best utilization of resin material and therefore results in a minimum amount of spent resins.Ion exchanger materials have been studied for removing heavy metals from a metal bearing wastes. For the current treatment,a facility has been designed for the removal of heavy metals from the acid mine drainage (AMD waste by the ion-exchange technology.

  14. Arsenic removal from acidic solutions with biogenic ferric precipitates

    Energy Technology Data Exchange (ETDEWEB)

    Ahoranta, Sarita H., E-mail: sarita.ahoranta@tut.fi [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Kokko, Marika E., E-mail: marika.kokko@tut.fi [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Papirio, Stefano, E-mail: stefano.papirio@unicas.it [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Özkaya, Bestamin, E-mail: bozkaya@yildiz.edu.tr [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Department of Environmental Engineering, Yildiz Technical University, Davutpasa Campus 34220, Esenler, Istanbul (Turkey); Puhakka, Jaakko A., E-mail: jaakko.puhakka@tut.fi [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland)

    2016-04-05

    Highlights: • Continuous and rapid arsenic removal with biogenic jarosite was achieved at pH 3.0. • Arsenic removal was inefficient below pH 2.4 due to reduced Fe–As co-precipitation. • As(V) had better sorption characteristics than As(III). • Biogenic jarosite adsorbed arsenic more effectively than synthetic jarosite. - Abstract: Treatment of acidic solution containing 5 g/L of Fe(II) and 10 mg/L of As(III) was studied in a system consisting of a biological fluidized-bed reactor (FBR) for iron oxidation, and a gravity settler for iron precipitation and separation of the ferric precipitates. At pH 3.0 and FBR retention time of 5.7 h, 96–98% of the added Fe(II) precipitated (99.1% of which was jarosite). The highest iron oxidation and precipitation rates were 1070 and 28 mg/L/h, respectively, and were achieved at pH 3.0. Subsequently, the effect of pH on arsenic removal through sorption and/or co-precipitation was examined by gradually decreasing solution pH from 3.0 to 1.6 (feed pH). At pH 3.0, 2.4 and 1.6, the highest arsenic removal efficiencies obtained were 99.5%, 80.1% and 7.1%, respectively. As the system had ferric precipitates in excess, decreased arsenic removal was likely due to reduced co-precipitation at pH < 2.4. As(III) was partially oxidized to As(V) in the system. In shake flask experiments, As(V) sorbed onto jarosite better than As(III). Moreover, the sorption capacity of biogenic jarosite was significantly higher than that of synthetic jarosite. The developed bioprocess simultaneously and efficiently removes iron and arsenic from acidic solutions, indicating potential for mining wastewater treatment.

  15. THIOGLYCOLIC ACID ESTERIFIED IN TO RICE STRAW FOR REMOVING LEAD FROM AQUEOUS SOLUTION

    Directory of Open Access Journals (Sweden)

    R. Gong

    2011-09-01

    Full Text Available Thiol rice straw (TRS was prepared by esterifying thioglycolic acid onto rice straw in the medium of acetic anhydride and acetic acid with sulfuric acid as catalyst. The sorption of lead (Pb on TRS from aqueous solution was subsequently investigated. The batch experiments showed that Pb removal was dependent on initial pH, sorbent dose, Pb concentration, contact time, and temperature. The maximum value of Pb removal appeared at pH 5. For 100 mg/L of Pb solution, a removal ratio of greater than 98% could be achieved with 2.0 g/L or more of TRS. The isothermal data of Pb sorption conformed well to the Langmuir model, and the maximum sorption capacity (Qm of TRS for Pb was 104.17 mg/g. The equilibrium of Pb removal was reached within 120 min. The Pb removal process could be described by the pseudo-first-order kinetic model. The thermodynamic study indicated that the Pb removal process was spontaneous and endothermic.

  16. Process for removal of hydrogen halides or halogens from incinerator gas

    Science.gov (United States)

    Huang, H.S.; Sather, N.F.

    1987-08-21

    A process for reducing the amount of halogens and halogen acids in high temperature combustion gas and through their removal, the formation of halogenated organics at lower temperatures, with the reduction being carried out electrochemically by contacting the combustion gas with the negative electrode of an electrochemical cell and with the halogen and/or halogen acid being recovered at the positive electrode.

  17. Mercury reduction and removal during high-level radioactive waste processing and vitrification

    International Nuclear Information System (INIS)

    Eibling, R.E.; Fowler, J.R.

    1981-01-01

    A reference process for immobilizing the high-level radioactive waste in borosilicate glass has been developed at the Savannah River Plant. This waste contains a substantial amount of mercury from separations processing. Because mercury will not remain in borosilicate glass at the processing temperature, mercury must be removed before vitrification or must be handled in the off-gas system. A process has been developed to remove mercury by reduction with formic acid prior to vitrification. Additional benefits of formic acid treatment include improved sludge handling and glass melter redox control

  18. Naphthenic acid removal from HVGO by alkaline earth metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ding, L.; Rahimi, P.; Hawkins, R.; Bhatt, S.; Shi, Y. [National Centre for Upgrading Technology, Devon, AB (Canada); Natural Resources Canada, Devon, AB (Canada). CanmetENERGY

    2009-07-01

    This poster highlighted a study that investigated naphthenic acid removal from bitumen-derived heavy vacuum gas oil (HVGO) by thermal cracking and catalytic decarboxylation over alkaline earth-metal oxides and ZnO catalysts in a batch reactor and a continuous fixed-bed reactor. X-ray diffraction (XRD), thermogravimetric-differential thermal analysis (TG-DTA) temperature-programmed desorption (TPD) of carbon dioxide (CO{sub 2}-TPD), and scanning electron microscopy were used to characterize the fresh and spent catalysts. With MgO and ZnO, naphthenic acid removal proceeded via catalytic decarboxylation. No crystalline phase changes were observed after reaction. With CaO, multiple pathways such as catalytic decarboxylation, neutralization, and thermal cracking were responsible for naphthenic acid conversion. The spent catalysts contained Ca(OH){sub 2} and CaCO{sub 3}. With BaO, naphthenic acid conversion occurred through neutralization. All BaO was converted to Ba(OH){sub 2} during the reaction. tabs., figs.

  19. Process to remove rare earth from IFR electrolyte

    International Nuclear Information System (INIS)

    Ackerman, J.P.; Johnson, T.R.

    1994-01-01

    The invention is a process for the removal of rare earths from molten chloride electrolyte salts used in the reprocessing of integrated fast reactor fuel (IFR). The process can be used either continuously during normal operation of the electrorefiner or as a batch process. The process consists of first separating the actinide values from the salt before purification by removal of the rare earths. After replacement of the actinides removed in the first step, the now-purified salt electrolyte has the same uranium and plutonium concentration and ratio as when the salt was removed from the electrorefiner. 1 fig

  20. Low removal of acidic and hydrophilic pharmaceutical products by various types of municipal wastewater treatment plants

    Directory of Open Access Journals (Sweden)

    Christian Gagnon

    2012-03-01

    Full Text Available Pharmaceutical substances represent a risk for aquatic environments and their potential impacts on the receiving environment are poorly understood. Municipal effluents are important sources of contaminants including common pharmaceuticals like anti-inflammatory and anti-convulsive substances. The removal of pharmaceuticals, particularly those highly soluble can represent a great challenge to conventional wastewater treatment processes. Hydrophilic drugs (e.g. acidic drugs have properties that can highly influence removal efficiencies of treatment plants. The performance of different wastewater treatment processes for the removal of specific pharmaceutical products that are expected to be poorly removed was investigated. The obtained results were compared to inherent properties of the studied substances. Clofibric acid, carbamazepine, diclofenac, ibuprofen and naproxen were largely found in physicochemical primary-treated effluents at concentrations ranging from 77 to 2384 ng/L. This treatment type showed removal yields lower than 30%. On the other hand, biological treatments with activated sludge under aerobic conditions resulted in much better removal rates (>50% for 5 of the 8 studied substances. Interestingly, this latter type of process showed evidence of selectivity with respect to the size (R2=0.7388, solubility (R2=0.6812, and partitioning (R2=0.9999 of the removed substances; the smallest and least sorbed substances seemed to be removed at better rates, while the persistent carbamazepine (392 ng/L and diclofenac (66 ng/L were poorly removed (<10% after biological treatment. In the case of treatment by aerated lagoons, the most abundant substances were the highly soluble hydroxy-ibuprofen (350-3321 ng/L, followed by naproxen (42-413 n/L and carbamazepine (254-386 ng/L. In order to assess the impacts of all these contaminants of various properties on the environment and human health, we need to better understand the chemical and physical

  1. Removal of Foodborne Pathogen Biofilms by Acidic Electrolyzed Water

    Directory of Open Access Journals (Sweden)

    Qiao Han

    2017-06-01

    Full Text Available Biofilms, which are complex microbial communities embedded in the protective extracellular polymeric substances (EPS, are difficult to remove in food production facilities. In this study, the use of acidic electrolyzed water (AEW to remove foodborne pathogen biofilms was evaluated. We used a green fluorescent protein-tagged Escherichia coli for monitoring the efficiency of AEW for removing biofilms, where under the optimal treatment conditions, the fluorescent signal of cells in the biofilm disappeared rapidly and the population of biofilm cells was reduced by more than 67%. Additionally, AEW triggered EPS disruption, as indicated by the deformation of the carbohydrate C-O-C bond and deformation of the aromatic rings in the amino acids tyrosine and phenylalanine. These deformations were identified by EPS chemical analysis and Raman spectroscopic analysis. Scanning electron microscopy (SEM images confirmed that the breakup and detachment of biofilm were enhanced after AEW treatment. Further, AEW also eradicated biofilms formed by both Gram-negative bacteria (Vibrio parahaemolyticus and Gram-positive bacteria (Listeria monocytogenes and was observed to inactivate the detached cells which are a potential source of secondary pollution. This study demonstrates that AEW could be a reliable foodborne pathogen biofilm disrupter and an eco-friendly alternative to sanitizers traditionally used in the food industry.

  2. Arsenic removal from acidic solutions with biogenic ferric precipitates.

    Science.gov (United States)

    Ahoranta, Sarita H; Kokko, Marika E; Papirio, Stefano; Özkaya, Bestamin; Puhakka, Jaakko A

    2016-04-05

    Treatment of acidic solution containing 5g/L of Fe(II) and 10mg/L of As(III) was studied in a system consisting of a biological fluidized-bed reactor (FBR) for iron oxidation, and a gravity settler for iron precipitation and separation of the ferric precipitates. At pH 3.0 and FBR retention time of 5.7h, 96-98% of the added Fe(II) precipitated (99.1% of which was jarosite). The highest iron oxidation and precipitation rates were 1070 and 28mg/L/h, respectively, and were achieved at pH 3.0. Subsequently, the effect of pH on arsenic removal through sorption and/or co-precipitation was examined by gradually decreasing solution pH from 3.0 to 1.6 (feed pH). At pH 3.0, 2.4 and 1.6, the highest arsenic removal efficiencies obtained were 99.5%, 80.1% and 7.1%, respectively. As the system had ferric precipitates in excess, decreased arsenic removal was likely due to reduced co-precipitation at pHremoves iron and arsenic from acidic solutions, indicating potential for mining wastewater treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Uranium recovery from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Carrington, O.F.; Pyrih, R.Z.; Rickard, R.S.

    1981-01-01

    Improvement in the process for recovering uranium from wetprocess phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange liquidliquid solvent extraction circuits in which in the first circuit (A) the uranium is reduced to the uranous form; (B) the uranous uranium is recovered by liquid-liquid solvent extraction using a mixture of mono- and di-(Alkyl-phenyl) esters of orthophosphoric acid as the ion exchange agent; and (C) the uranium oxidatively stripped from the agent with phosphoric acid containing an oxidizing agent to convert uranous to uranyl ions, and in the second circuit (D) recovering the uranyl uranium from the strip solution by liquid-liquid solvent extraction using di(2ethylhexyl)phosphoric acid in the presence of trioctylphosphine oxide as a synergist; (E) scrubbing the uranium loaded agent with water; (F) stripping the loaded agent with ammonium carbonate, and (G) calcining the formed ammonium uranyl carbonate to uranium oxide, the improvement comprising: (1) removing the organics from the raffinate of step (B) before recycling the raffinate to the wet-process plant, and returning the recovered organics to the circuit to substantially maintain the required balance between the mono and disubstituted esters; (2) using hydogren peroxide as the oxidizing agent in step (C); (3) using an alkali metal carbonate as the stripping agent in step (F) following by acidification of the strip solution with sulfuric acid; (4) using some of the acidified strip solution as the scrubbing agent in step (E) to remove phosphorus and other impurities; and (5) regenerating the alkali metal loaded agent from step (F) before recycling it to the second circuit

  4. Lignor process for acidic rock drainage treatment.

    Science.gov (United States)

    Zhuang, J M; Walsh, T

    2004-09-01

    The process using lignosulfonates for acidic rock drainage (ARD) treatment is referred to as the Lignor process. Lignosulfonates are waste by-products produced in the sulfite pulping process. The present study has shown lignosulfonates are able to protect lime from developing an external surface coating, and hence to favor its dissociation. Further, the addition of lignosulfonates to ARD solutions increased the dotting and settling rate of the formed sludge. The capability of lignosulfonates to form stable metal-lignin complexes makes them very useful in retaining metal ions and thus improving the long-term stability of the sludge against leaching. The Lignor process involves metal sorption with lignosulfonates, ARD neutralization by lime to about pH 7, pH adjustment with caustic soda to 9.4 - 9.6, air oxidation to lower the pH to a desired level, and addition of a minimum amount of FeCl3 for further removal of dissolved metals. The Lignor process removes all concerned metals (especially Al and Mn) from the ARD of the Britannia Mine (located at Britannia Beach, British Columbia, Canada) to a level lower than the limits of the B.C. Regulations. Compared with the high-density sludge (HDS) process, the Lignor process has many advantages, such as considerable savings in lime consumption, greatly reduced sludge volume, and improved sludge stability.

  5. Studies on Removal of Dyes from wastewater using Electro-coagulation Process

    OpenAIRE

    N B. Patel; B D. Soni; J P. Ruparelia

    2000-01-01

    Electro-coagulation (EC) is one of the effective techniques to remove colour, COD and organic compounds from wastewater. In this paper electro coagulation technique has been used for the removal of colour and COD from dye solutions containing Direct Black 22 and Acid Red 97 using batch process. For batch the process effect of operational parameters such as current density, initial pH of the solution, time of electrolysis and electrode materials were studied to attempt max...

  6. Bidentate organophosphorus extractants: purification, properties and applications to removal of actinides from acidic waste solutions

    International Nuclear Information System (INIS)

    Schulz, W.W.; McIsaac, L.D.

    1977-05-01

    At both Hanford and Idaho, DHDECMP (dihexyl-N, N-diethylcarbamylmethylene phosphonate) continuous counter-current solvent extraction processes are being developed for removal of americium, plutonium, and, in some cases, other actinides from acidic wastes generated at these locations. Bench and, eventually, pilot and plant-scale testing and application of these processes have been substantially enhanced by the discovery of suitable chemical and physical methods of removing deleterious impurities from technical-grade DHDECMP. Flowsheet details, as well as various properties of purified DHDECMP extractants, are enumerated

  7. Removal of radionuclides from acid mine waters by retention on adsorbing materials

    International Nuclear Information System (INIS)

    Nascimento, M.R.L.; Fukuma, H.T.; Costa da, W.C.; Quinelato, A.L.; Gomes, H.A.; Garcia, O.Jr.

    2006-01-01

    This study proposes a method for decontamination of acid drainage water from a uranium mine, as an alternative process to lime treatment. The research embodied the recovery of uranium with an ion-exchange resin, treatment of effluent resin with lime, or with inorganic adsorbents and biosorbents. The uranium decontamination level using the resin process was 94% and allowed the recovery of this element as a commercial product. Among the inorganic adsorbents studied, phosphogypsum was effective for 226 Ra, 228 Ra, and 210 Pb removal. Among the biosorbents, Sargassum sp. was superior in relation to its specific capacity to accumulate and remove 226 Ra. (author)

  8. Process for lead removal from rare earth

    International Nuclear Information System (INIS)

    Bollat, A.; Sabot, J.L.

    1987-01-01

    An aqueous solution of rare earth chlorides and lead chlorides, with a chloride concentration of at least 2 moles/liter and a pH between 2 and 4, is extracted by an alkylphosphonic acid ester and rare earth(s) is (are) recovered from the organic phase [fr

  9. Cesium removal from liquid acidic wastes with the primary focus on ammonium molybdophosphate as an ion exchanger: A literature review

    International Nuclear Information System (INIS)

    Miller, C.J.

    1995-03-01

    Many articles have been written concerning the selective removal of cesium from both acidic and alkaline defense wastes. The majority of the work performed for cesium removal from defense wastes involves alkaline feed solutions. Several different techniques for cesium removal from acidic solutions have been evaluated such as precipitation, solvent extraction, and ion exchange. The purpose of this paper is to briefly review various techniques for cesium removal from acidic solutions. The main focus of the review will be on ion exchange techniques, particularly those involving ammonium molybdophosphate as the exchanger. The pertinent literature sources are condensed into a single document for quick reference. The information contained in this document was used as an aid in determining techniques to evaluate cesium removal from the acidic Idaho Chemical Processing Plant waste matrices. 47 refs., 2 tabs

  10. Process for recovering uranium from wet process phosphoric acid

    International Nuclear Information System (INIS)

    Pyrih, R.Z.; Rickard, S.; Carrington, F.

    1982-01-01

    A process for recovering uranium from phosphoric acid solutions uses an acidified alkali metal carbonate solution for the second-stage strip of uranyl uranium from the ion-exchange solution. The stripped solution is then recycled to the ion-exchange circuit. In the first stripping stage the ion-exchange solution containing the recovered uranyl uranium and an inert organic diluent is stripped with ammonium carbonate, producing a slurry of ammonium uranyl tricarbonate. The second strip, with a solution of 50-200 grams per litre of sodium carbonate eliminates the problems of inadequate removal of phosphorus, iron and vanadium impurities, solids accumulation, and phase separation in the strip circuit

  11. The Influence of Parameters Affecting Boron Removal by Electrocoagulation Process

    KAUST Repository

    Zeboudji, B.; Drouiche, Nadjib; Lounici, Hakim; Mameri, Nabil; Ghaffour, NorEddine

    2013-01-01

    , this process requires chemical addition and important additional investment, operation and maintenance, and energy costs. Electrocoagulation (EC) process can be used to achieve such low boron concentration. In this work, the removal of boron from aqueous

  12. Study on arsenic removal process from water

    Directory of Open Access Journals (Sweden)

    B Bayarmaa

    2014-09-01

    Full Text Available In this study a novel adsorbent, iron oxide, is used for As (V or As (III removal. Some ferric oxides have been reported to be effective for arsenic removal. Ferric oxides powder is a good adsorbent material since it’s has magnetic properties and a good adsorption capacity. The main purpose of this study has been focused on to study the relationship between adsorption capacity (ability, performance and the surface characteristics of the ferric oxide. Prepared sample’s capacity was evaluated. The value was 26.1-67.4 mg/g for As (V and 20.5-47.8 mg/g for As (III. pH dependence was evaluated and when pH increasing, adsorption capacity was decreased. The kinetic was evaluated and about 12 hours reached equilibrium and a capacity of 49 mg/g for As (V and 42 mg/g for As(III was gained. The kinetic constants for arsenic adsorption on the ferrihydrite adsorbent’s were fitted.DOI: http://dx.doi.org/10.5564/mjc.v12i0.172 Mongolian Journal of Chemistry Vol.12 2011: 53-55

  13. REMOVAL OF ARSENIC FROM DRINKING WATER SUPPLIES BY IRON REMOVAL PROCESS

    Science.gov (United States)

    This design manual is an in-depth presentation of the steps required to design and operate a water treatment plant for removal of arsenic in the As (V) form from drinking water using an iron removal process. The manual also discusses the capital and operating costs including many...

  14. Sodium removal by alcohol process: Basic tests and its application

    International Nuclear Information System (INIS)

    Nakai, S.; Yamamoto, S.; Akai, M.; Yatabe, T.

    1997-01-01

    We have various methods for sodium removal; an alcohol cleaning process, a steam cleaning process and a direct burning process. Sodium removal by the alcohol process has a lot of advantages, such as causing no alkali corrosion to steel, short processing time and easy operation. Therefore the alcohol process was selected for the 1MWt double wall tube straight type steam generator. We have already had some experiences of the alcohol process, while still needed to confirm the sodium removal rate in the crevice and to develop an on-line sodium concentration monitoring method in alcohol during sodium removal. We have conducted the small scale sodium removal test with flowing alcohol where the sodium removal rate in the crevice and the alcohol conductivity were measured as functions of sodium concentration in alcohol and alcohol temperature. The sodium removal of the DWTSG was conducted by the devised alcohol process safely and efficiently. The process hour was about 1 day. Visual inspection during dismantling of the DWTSG showed no evidence of any un-reacted sodium. (author)

  15. Thermodynamic modelling of acid gas removal from natural gas using the Extended UNIQUAC model

    DEFF Research Database (Denmark)

    Sadegh, Negar; Stenby, Erling Halfdan; Thomsen, Kaj

    2017-01-01

    Thermodynamics of natural gas sweetening process needs to be known for proper design of natural gas treating plants. Absorption with aqueous N-Methyldiethanolamine is currently the most commonly used process for removal of acid gas (CO2 and H2S) impurities from natural gas. Model parameters...... for the Extended UNIQUAC model have already been determined by the same authors to calculate single acid gas solubility in aqueous MDEA. In this study, the model is further extended to estimate solubility of CO2 and H2S and their mixture in aqueous MDEA at high pressures with methane as a makeup gas....

  16. [Impurity removal technology of Tongan injection in liquid preparation process].

    Science.gov (United States)

    Yang, Xu-fang; Wang, Xiu-hai; Bai, Wei-rong; Kang, Xiao-dong; Liu, Jun-chao; Wu, Yun; Xiao, Wei

    2015-08-01

    In order to effectively remove the invalid impurities in Tongan injection, optimize the optimal parameters of the impurity removal technology of liquid mixing process, in this paper, taking Tongan injection as the research object, with the contents of celandine alkali, and sinomenine, solids reduction efficiency, and related substances inspection as the evaluation indexes, the removal of impurities and related substances by the combined process of refrigeration, coction and activated carbon adsorption were investigated, the feasibility of the impurity removal method was definited and the process parameters were optimized. The optimized process parameters were as follows: refrigerated for 36 h, boiled for 15 min, activated carbon dosage of 0.3%, temperature 100 degrees C, adsorption time 10 min. It can effectively remove the tannin, and other impurities, thus ensure the quality and safety of products.

  17. Paracetamol and salicylic acid removal from contaminated water by microalgae.

    Science.gov (United States)

    Escapa, C; Coimbra, R N; Paniagua, S; García, A I; Otero, M

    2017-12-01

    The biomass growth, pharmaceutical removal and light conversion efficiency of Chlorella sorokiniana under the presence of paracetamol (PC) and salicylic acid (SaC) were assessed and compared at two different concentrations of these pharmaceuticals (I: 25 mg l -1 , II: 250 mg l -1 ). Microalgae were resistant to these concentrations and, moreover, their growth was significantly stimulated (p ≤ 0.05) under these drugs (biomass concentration increased above 33% PCI, 35% SaCI, 13% PCII and 45% SaCII, as compared with the respective positive controls). At the steady state of the semicontinuous culture, C. sorokiniana showed removal efficiencies above 41% and 69% for PCI and PCII, respectively; and above 93% and 98% for SaCI and SaCII, respectively. Under an irradiance of 370 μE m -2  s -1 , higher quantum yields were reached by microalgae under the presence of drugs, either at dose I or II, than by the respective positive controls. These results point to C. sorokiniana as a robust strain for the bioremediation of paracetamol and salicylic acid concentrated wastewaters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Biological nitrate removal processes from drinking water supply-a review.

    Science.gov (United States)

    Mohseni-Bandpi, Anoushiravan; Elliott, David Jack; Zazouli, Mohammad Ali

    2013-12-19

    This paper reviews both heterotrophic and autotrophic processes for the removal of nitrate from water supplies. The most commonly used carbon sources in heterotrophic denitrification are methanol, ethanol and acetic acid. Process performance for each feed stock is compared with particular reference nitrate and nitrite residual and to toxicity potential. Autotrophic nitrate removal has the advantages of not requiring an organic carbon source; however the slow growth rate of autotrophic bacteria and low nitrate removal rate have contributed to the fact that relatively few full scale plants are in operation at the present time.

  19. Extremely acidic mine lake ecosystems in Lusatia (Germany) : characterisation and development of sustainable, biology-based acidity removal technologies

    International Nuclear Information System (INIS)

    Fyson, A.; Deneke, R.; Nixdorf, B.; Steinberg, C.E.W.

    2003-01-01

    There are approximately 500 infilled open-cast lignite pits in Germany that are extremely acidic because of high concentrations of dissolved metals, mostly iron and aluminium. The mining lakes have pH values of 2.4 to 3.4 and also have high sulphate concentrations. Efforts are being made to neutralize the lakes for recreational purposes. The acidity can be removed from the lakes in an economical and environmentally sustainable manner by flooding through diversion of neutral, nutrient-rich river water. This paper described the living conditions of the acidic mining lakes in the Lausitz region of Germany and summarized the benefits of the controlled eutrophication approach to enhance natural, self-sustaining processes for acid neutralization. Compared to infilling with river water, eutrophication increases lake productivity and removes acidity through sediment bound and water column biologically-mediated processes. The study involved basic research on particle transport in streams and lakes, pelagic food web interactions and submerged macrophyte metabolism. It also looked at the role of wetlands, bacterial interactions at the water-sediment interface, and modelling. It was shown that the addition of phosphorus and carbon to the water column can enhance primary production. Future studies will examine environmentally acceptable treatment strategies that offer an alternative to chemical treatment. 20 refs., 1 tab., 2 figs

  20. The removal of uranium from acidic media using ion exchange and/or extraction chromatography

    International Nuclear Information System (INIS)

    FitzPatrick, J.R.; Schake, B.S.; Murphy, J.; Holmes, K.; West, M.H.

    1996-06-01

    The separation and purification of uranium from either nitric acid or hydrochloric acid media can be accomplished by using either solvent extraction or ion-exchange. Over the past two years at Los Alamos, emerging programs are focused on recapturing the expertise required to do limited, small-quantity processing of enriched uranium. During this period of time, we have been investigating ion-addition, waste stream polishing is associated with this effort in order to achieve more complete removal of uranium prior to recycle of the acid. Extraction chromatography has been demonstrated to further polish the uranium from both nitric and hydrochloric acid media thus allowing for a more complete recovery of the actinide material and creation of less waste during the processing steps

  1. Characterization of commercial ceramic adsorbents and its application on naphthenic acids removal of petroleum distillates

    Directory of Open Access Journals (Sweden)

    Juliana Pereira Silva

    2007-06-01

    Full Text Available The mixture of carboxylic acids present in petroleum oil and directly responsible for its acidity and corrosiveness in liquid phase during the refine process is denominated "naphthenic acids". These acids are also present in distilled fraction of petroleum, causing several problems in final products quality. A possible way to remove the carboxilic acids from petroleum distilled fractions is the adsorption in porous materials. However, the results obtained until now indicate that ion exchange resins would be the best adsorbents for this process, which would probably increase its cost. In this work, two commercial adsorbents (clay and activated alumina were characterized by a set of physical-chemistry techniques and evaluated concerning their capacity of removing naphthenic acids from a light petroleum fraction. It was verified the influence of a thermal treatment previous to the adsorption in its physical-chemistry characteristics and its properties. A high reduction of the TAN values was verified in the residual oils from both adsorbent, although there was a competition among all the compounds present in the light oil fraction for the adsorption sites, which can be probably related to the thermal pre-treatment. These results were related to corrosion yield experiments, and it was observed that the adsorbent pretreatment also affected the reduction in corrosion yields for both alumina and clay.

  2. Optimization of coagulation-flocculation process for colour removal ...

    African Journals Online (AJOL)

    Response surface methodology (RSM) using face-centered central composite design (FCCD) was used to optimize the four variables. Increase in the colour removal efficiency was higher in acidic solution pH. Accurate control of coagulant dosages gave optimum destabilization of charged particles and re-stabilization ...

  3. optimization of coagulation-flocculation process for colour removal

    African Journals Online (AJOL)

    user

    2DEPARTMENT OF CHEMICAL ENGINEERING, NNAMDI AZIKIWE UNIVERSITY, AWKA, ANAMBRA STATE. ... The ability of organic polymer rich coagulants for colour removal from acid dye was studied. ... Response surface methodology (RSM) using face-centered ...... successfully applied for modeling and optimizing the.

  4. Removal of sulfur from process streams

    International Nuclear Information System (INIS)

    Brignac, D.G.

    1984-01-01

    A process wherein water is added to a non-reactive gas stream, preferably a hydrogen or hydrogen-containing gas stream, sufficient to raise the water level thereof to from about 0.2 percent to about 50 percent, based on the total volume of the process gas stream, and the said moist gas stream is contacted, at elevated temperature, with a particulate mass of a sulfur-bearing metal alumina spinel characterized by the formula MAl 2 O 4 , wherein M is chromium, iron, cobalt, nickel, copper, cadmium, mercury, or zinc to desorb sulfur thereon. In the sulfur sorption cycle, due to the simultaneous adsorption of water and sulfur, the useful life of the metal alumina spinel for sulfur adsorption can be extended, and the sorbent made more easily regenerable after contact with a sulfur-bearing gas stream, notably sulfur-bearing wet hydrogen or wet hydrogen-rich gas streams

  5. Removal of radionuclides from process streams - a review

    International Nuclear Information System (INIS)

    Itzkovitch, I.J.; Ritcey, G.M.

    1979-04-01

    This report details the origin and control of radium 226, thorium 230 and lead 210 contamination of mill effluent streams from conventional and non-conventional milling of uranium ores, reviews the basic chemistry of the radionuclides as it relates to potential alternatives for control and presents these alternatives along with a summary of published cost data. The conclusions from the study indicate that the current technology, using sulphuric acid processing, solubilizes only a comparatively small quantity of the radionuclides, with the solid containing approximately the same concentration as the original ore. Present technolgy does not provide for complete removal and isolation of the radionuclides. Current practice for control of thorium 230 in liquid effluents by neutralization is adequate to meet present Governmental guidelines. Radium in solution is presently being controlled by precipitation with barium chloride but levels of less than 3 pCi/L of soluble radium could be difficult if not impossible to achieve consistently by this treatment. Indications are that the concentration of lead 210 in liquid effluent may exceed present guidelines. No specific control procedures are employed for lead 210. Methods of isolating radium 226 are required for treating effluents from conventional milling as well as from alternative processes under development. Ion exchange is suggested as a means of isolating these radionuclides. (OT)

  6. Phosphate cellulose with metaphosphoric acid for dye removal

    International Nuclear Information System (INIS)

    Silva, S.C.C.; Silva, F.C.; Lima, L.C.B.; Santos, M.R.M.C.; Osajima, J.A.; Silva Filho, E.C. da

    2014-01-01

    The chemical modification of cellulose is a suitable method used for producing value-added products, making them more efficient and selective for certain applications such as adsorption of dye. Thus the aim of this study was to modify the natural cellulose with metaphosphoric acid, characterized it through the techniques of FTIR and "3"1P NMR and applies it in the adsorption of brilliant green dye, evaluating the kinetic models of pseudo first-order and pseudo second-order and the theoretical models of the Langmuir, Freundlich and Temkin isotherms. The characterizations demonstrated the effectiveness of the modification, the maximum adsorption capacity was 150.0 mg g-1, adjusting better to the kinetic model of pseudo-second order and the theoretical model of Temkin, with the adsorbent showing efficient for removal of brilliant green dye. (author)

  7. Acid Green 1 removal from wastewater by layered double hydroxides

    Science.gov (United States)

    Elkhattabi, El Hassan; Lakraimi, Mohamed; Berraho, Moha; Legrouri, Ahmed; Hammal, Radouan; El Gaini, Layla

    2018-03-01

    The paper presents the removal of Acid Green 1 (AG1) from aqueous solutions by [Zn-Al-Cl]-layered double hydroxides (LDHs). The LDH was prepared by coprecipitation at constant pH. The affinity of this material for AG1 was studied as a function of contact time, pH of the solution, LDH dose and AG1/LDH mass ratio. It was found that 32 h are enough to reach the equilibrium with a maximum retention at pH 8 for an LDH dose of 100 mg and with an AG1/LDH mass ratio higher than 2. The adsorption isotherm is of L-type, as described by the Langmuir model. The results demonstrate that AG1 retention on LDHs occurs by adsorption on external surface when AG1/LDH mass ratio is equal or lower than 2 and by both adsorption and interlayer ion exchange for ratios higher than 2. A mechanism for the AG1 removal has been confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric-differential thermal analyses and scanning electron microscopy.

  8. Removal of pharmaceuticals from wastewater by biological processes, hydrodynamic cavitation and UV treatment.

    Science.gov (United States)

    Zupanc, Mojca; Kosjek, Tina; Petkovšek, Martin; Dular, Matevž; Kompare, Boris; Širok, Brane; Blažeka, Željko; Heath, Ester

    2013-07-01

    To augment the removal of pharmaceuticals different conventional and alternative wastewater treatment processes and their combinations were investigated. We tested the efficiency of (1) two distinct laboratory scale biological processes: suspended activated sludge and attached-growth biomass, (2) a combined hydrodynamic cavitation-hydrogen peroxide process and (3) UV treatment. Five pharmaceuticals were chosen including ibuprofen, naproxen, ketoprofen, carbamazepine and diclofenac, and an active metabolite of the lipid regulating agent clofibric acid. Biological treatment efficiency was evaluated using lab-scale suspended activated sludge and moving bed biofilm flow-through reactors, which were operated under identical conditions in respect to hydraulic retention time, working volume, concentration of added pharmaceuticals and synthetic wastewater composition. The suspended activated sludge process showed poor and inconsistent removal of clofibric acid, carbamazepine and diclofenac, while ibuprofen, naproxen and ketoprofen yielded over 74% removal. Moving bed biofilm reactors were filled with two different types of carriers i.e. Kaldnes K1 and Mutag BioChip™ and resulted in higher removal efficiencies for ibuprofen and diclofenac. Augmentation and consistency in the removal of diclofenac were observed in reactors using Mutag BioChip™ carriers (85%±10%) compared to reactors using Kaldnes carriers and suspended activated sludge (74%±22% and 48%±19%, respectively). To enhance the removal of pharmaceuticals hydrodynamic cavitation with hydrogen peroxide process was evaluated and optimal conditions for removal were established regarding the duration of cavitation, amount of added hydrogen peroxide and initial pressure, all of which influence the efficiency of the process. Optimal parameters resulted in removal efficiencies between 3-70%. Coupling the attached-growth biomass biological treatment, hydrodynamic cavitation/hydrogen peroxide process and UV treatment

  9. Conditioned of process of water removal product radioactive and non-radioactive genesis

    International Nuclear Information System (INIS)

    Shevchenko, O.L.

    2011-01-01

    The analysis mode of soluble organic matter in natural humic water drainage channels left bank of Pripyat and its dependence on the hydrodynamic and hydrological factors. Proved the existence of the concentration of 90 Sr in the water on the content of fulvic acid in it. Quantified removal of humic acids of groundwater and surface runoff. Emphasizes the primary role in the removal of humic substances and significant - in the mobilization of 90 Sr processes of secondary swamping of the surface watershed and eutrophication of waterways, which have acquired extensive development on the alienation of the territory for 25 years after the Chernobyl disaster.

  10. Selective binding behavior of humic acid removal by aluminum coagulation.

    Science.gov (United States)

    Jin, Pengkang; Song, Jina; Yang, Lei; Jin, Xin; Wang, Xiaochang C

    2018-02-01

    The reactivity characteristics of humic acid (HA) with aluminium coagulants at different pH values was investigated. It revealed that the linear complexation reaction occurred between aluminum and humic acid at pH aluminum existed in the form of free aluminum and remained unreacted in the presence of HA until the concentration reached to trigger Al(OH) 3(s) formation. Differentiating the change of functional groups of HA by 1 H nuclear magnetic resonance spectroscopy and X-ray photoelectron spectra analysis, it elucidated that there was a selective complexation between HA and Al with lower Al dosage at pH 5, which was probably due to coordination of the activated functional groups onto aluminium. While almost all components were removed proportionally by sweep adsorption without selectivity at pH 7, as well as that with higher Al dosage at pH 5. This study provided a promising pathway to analyse the mechanism of the interaction between HA and metal coagulants in future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Image processing on the image with pixel noise bits removed

    Science.gov (United States)

    Chuang, Keh-Shih; Wu, Christine

    1992-06-01

    Our previous studies used statistical methods to assess the noise level in digital images of various radiological modalities. We separated the pixel data into signal bits and noise bits and demonstrated visually that the removal of the noise bits does not affect the image quality. In this paper we apply image enhancement techniques on noise-bits-removed images and demonstrate that the removal of noise bits has no effect on the image property. The image processing techniques used are gray-level look up table transformation, Sobel edge detector, and 3-D surface display. Preliminary results show no noticeable difference between original image and noise bits removed image using look up table operation and Sobel edge enhancement. There is a slight enhancement of the slicing artifact in the 3-D surface display of the noise bits removed image.

  12. USE OF AN EQUILIBRIUM MODEL TO FORECAST DISSOLUTION EFFECTIVENESS, SAFETY IMPACTS, AND DOWNSTREAM PROCESSABILITY FROM OXALIC ACID AIDED SLUDGE REMOVAL IN SAVANNAH RIVER SITE HIGH LEVEL WASTE TANKS 1-15

    International Nuclear Information System (INIS)

    KETUSKY, EDWARD

    2005-01-01

    This thesis details a graduate research effort written to fulfill the Magister of Technologiae in Chemical Engineering requirements at the University of South Africa. The research evaluates the ability of equilibrium based software to forecast dissolution, evaluate safety impacts, and determine downstream processability changes associated with using oxalic acid solutions to dissolve sludge heels in Savannah River Site High Level Waste (HLW) Tanks 1-15. First, a dissolution model is constructed and validated. Coupled with a model, a material balance determines the fate of hypothetical worst-case sludge in the treatment and neutralization tanks during each chemical adjustment. Although sludge is dissolved, after neutralization more is created within HLW. An energy balance determines overpressurization and overheating to be unlikely. Corrosion induced hydrogen may overwhelm the purge ventilation. Limiting the heel volume treated/acid added and processing the solids through vitrification is preferred and should not significantly increase the number of glass canisters

  13. Sequential Washing with Electrolyzed Alkaline and Acidic Water Effectively Removes Pathogens from Metal Surfaces.

    Directory of Open Access Journals (Sweden)

    Yuichiro Nakano

    Full Text Available Removal of pathogenic organisms from reprocessed surgical instruments is essential to prevent iatrogenic infections. Some bacteria can make persistent biofilms on medical devices. Contamination of non-disposable equipment with prions also represents a serious risk to surgical patients. Efficient disinfection of prions from endoscopes and other instruments such as high-resolution cameras remains problematic because these instruments do not tolerate aggressive chemical or heat treatments. Herein, we develop a new washing system that uses both the alkaline and acidic water produced by electrolysis. Electrolyzed acidic water, containing HCl and HOCl as active substances, has been reported to be an effective disinfectant. A 0.15% NaCl solution was electrolyzed and used immediately to wash bio-contaminated stainless steel model systems with alkaline water (pH 11.9 with sonication, and then with acidic water (pH 2.7 without sonication. Two bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa and a fungus (Candida albicans were effectively removed or inactivated by the washing process. In addition, this process effectively removed or inactivated prions from the stainless steel surfaces. This washing system will be potentially useful for the disinfection of clinical devices such as neuroendoscopes because electrolyzed water is gentle to both patients and equipment and is environmentally sound.

  14. Removal of emerging perfluorooctanoic acid and perfluorooctane sulfonate contaminants from lake water.

    Science.gov (United States)

    Pramanik, Biplob Kumar; Pramanik, Sagor Kumar; Sarker, Dipok Chandra; Suja, Fatihah

    2017-08-01

    Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are the major polyfluoroalkyl substances (PFASs) contaminating global water environment. This study investigated the efficiency of granular activated carbon (GAC), ultrafiltration (UF) and nanofiltration (NF) treatment for removing PFOS and PFOA contaminants from lake water. NF gave greater removal of all contaminant types (in terms of organic matter, PFOS and PFOA) than GAC treatment which in turn was greater than UF treatment. The lower removal by UF was due to larger pore size of the membrane compared to the size of the target contaminants. For all treatment processes, lower pH (4) in the feedwater showed greater rejection of the organics and selected PFASs. This was likely due to increase in the electrostatic repulsion between solute and sorbent. It could be observed that on increasing the concentration of organics in the feed solution, the rejection of PFOA/PFOS decreased which was due to competition between organics and PFOS/PFOA for binding sites on the membrane/activated carbon surface. It was also noted that protein content led to greater influence for lower rejection of the PFOA/PFOS than carbohydrate or DOC content. This study demonstrated the potential use of membrane processes for removing emerging persistent organic pollutant removal from lake water.

  15. Process for removing heavy metal compounds from heavy crude oil

    Science.gov (United States)

    Cha, Chang Y.; Boysen, John E.; Branthaver, Jan F.

    1991-01-01

    A process is provided for removing heavy metal compounds from heavy crude oil by mixing the heavy crude oil with tar sand; preheating the mixture to a temperature of about 650.degree. F.; heating said mixture to up to 800.degree. F.; and separating tar sand from the light oils formed during said heating. The heavy metals removed from the heavy oils can be recovered from the spent sand for other uses.

  16. Application of KWU antimony removal process at Gentilly-2

    International Nuclear Information System (INIS)

    Dundar, Y.; Odar, S.; Streit, K.; Allsop, H.; Guzonas, D.

    1996-09-01

    This paper describes the work performed to adapt the KWU PWR antimony removal process to CANDU plant conditions, and the application of the process at the Hydro Quebec unit, Gentilly-2. The results of the application will be presented and the 'lessons learned' will be discussed in detail. (author)

  17. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lingling, E-mail: lasier_wang@hotmail.com [College of Chemical Engineering and Materials, Quanzhou Normal University, Quanzhou 362000, Fujian (China); Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Han, Changseok [ORISE Post-doctoral Fellow, The U.S. Environmental Protection Agency, ORD, NRMRL, STD, CPB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Nadagouda, Mallikarjuna N. [The U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, WQMB, 26 W. Martin Luther King Jr. Drive, Cincinnati, OH 45268 (United States); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Nireas-International Water Research Centre, School of Engineering, University of Cyprus, PO Box 20537, 1678, Nicosia (Cyprus)

    2016-08-05

    Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO{sub 3}){sub 2}·6H{sub 2}O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g{sup −1}. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

  18. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    International Nuclear Information System (INIS)

    Wang, Lingling; Han, Changseok; Nadagouda, Mallikarjuna N.; Dionysiou, Dionysios D.

    2016-01-01

    Highlights: • An innovative adsorbent was successfully synthesized to remove humic acid. • The adsorbent possessed high adsorption capacity for humic acid. • The adsorption capacity remarkably increased after an acid modification. • The adsorption capacity was proportional to the amount of ZnO coated on zeolite. • Electrostatic interactions are a major factor at the first stage of the process. - Abstract: Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO_3)_2·6H_2O functionalization of zeolite 4A. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The synthesized materials were characterized by porosimetry analysis, scanning electron microscopy, X-Ray diffraction analysis, and high resolution transmission electron microscopy. The maximum adsorption capacity of the adsorbents at 21 ± 1 °C was about 60 mgC g"−"1. The results showed that the positive charge density of ZnO-coated zeolite adsorbents was proportional to the amount of ZnO coated on zeolite and thus, ZnO-coated zeolite adsorbents exhibited a greater affinity for negatively charged ions. Furthermore, the adsorption capacity of ZnO-coated zeolite adsorbents increased markedly after acid modification. Adsorption experiments demonstrated ZnO-coated zeolite adsorbents possessed high adsorption capacity to remove HA from aqueous solutions mainly due to strong electrostatic interactions between negative functional groups of HA and the positive charges of ZnO-coated zeolite adsorbents.

  19. Bisphenol A Removal by Submerged Macrophytes and the Contribution of Epiphytic Microorganisms to the Removal Process.

    Science.gov (United States)

    Zhang, Guosen; Wang, Yu; Jiang, Jinhui; Yang, Shao

    2017-06-01

    Bisphenol A (BPA), a typical endocrine disruptor, has been found in global aquatic environments, causing great concern. The capabilities of five common submerged macrophytes to remove BPA from water and the contributions of epiphytic microorganisms were investigated. Macrophytes removed 62%-100% of total BPA (5 mg/L) over 12 days; much higher rates than that observed in the control (2%, F = 261.511, p = 0.000). Ceratophyllum demersum was the most efficient species. C. demersum samples from lakes with different water qualities showed no significant differences in BPA removal rates. Moreover, removal, inhibition or re-colonization of epiphytic microorganisms did not significantly change the BPA removal rates of C. demersum. Therefore, the contributions of epiphytic microorganisms to the BPA removal process were negligible. The rate of BPA accumulation in C. demersum was 0.1%, indicating that BPA was mainly biodegraded by the macrophyte. Hence, submerged macrophytes, rather than epiphytic microorganisms, substantially contribute to the biodegradation of BPA in water.

  20. Acid decomposition processing system for radioactive wastes

    International Nuclear Information System (INIS)

    Oomine, Toshimitsu.

    1984-01-01

    Purpose: To perform plutonium recovery at a low energy consumption irrespective of the plutonium density within the wastes. Method: In a decomposing and volume-reducing device for combustible or less combustible wastes containing transuranic elements using an acid, the wastes are in contact with nitric acid before feeding to a reactor. Then, the transuranic elements are transferred into the nitric acid, which is then in contact with ion exchange resins. After adsorbing the transuranic elements to the ion exchange resins, the nitric acid removed with the transuranic elements is caused to flow into a reaction vessel or heating vessel and used as a decomposing and oxidizing agent. (Seki, T.)

  1. Pretreatment of phosphoric acid for uranium recovery by the wet phosphoric acid process

    International Nuclear Information System (INIS)

    Chern, S.L.P.; Chen, Y.C.L.; Chang, S.S.H.; Kuo, T.S.; Ting, G.C.M.

    1980-01-01

    The proposal deals with reprocessing of phosphoric acid arising from uranium separation according to the wet phosphoric acid process and being intended for recycling. In detail, the sludge will be removed by means of an inclined separating device containing corrugated plates, then the organic impurities are washed out with kerosene in suitable facilities, and the crude phase remaining in the settling tank will be separated from the kerosene in a separating centrifuge. The method has only got low cost of installation. (UWI) [de

  2. The Influence of Parameters Affecting Boron Removal by Electrocoagulation Process

    KAUST Repository

    Zeboudji, B.

    2013-04-01

    Boron removal in seawater desalination presents a particular challenge. In seawater reverse osmosis (SWRO) systems boron removal at low concentration (<0.5 mg/L) is usually achieved by a second pass using brackish water RO membranes. However, this process requires chemical addition and important additional investment, operation and maintenance, and energy costs. Electrocoagulation (EC) process can be used to achieve such low boron concentration. In this work, the removal of boron from aqueous solution was carried out by EC process using aluminum and iron electrodes. Several operating parameters on the removal efficiency such as initial pH, current density, initial boron ion concentration, feed concentration, gap between electrodes, and electrode material, were investigated. In the case of bipolar electrocoagulation (BEC), an optimum removal efficiency of 96% corresponding to a final boron concentration of 0.4 mg/L was achieved at a current density of 6 mA/cm2 and pH = 8 using aluminum electrodes. The concentration of NaCl was 2,500 mg/L and the gap between the electrodes of 0.5 cm. Furthermore, a comparison between monopolar electrocoagulation (MEC) and BEC using both aluminum and iron electrodes was carried out. Results showed that the BEC process has reduced the current density applied to obtain high level of boron removal in a short reaction time compared to MEC process. The high performance of the EC showed that the process could be used to reduce boron concentration to acceptable levels at low-cost and more environmentally friendly. © 2013 Copyright Taylor and Francis Group, LLC.

  3. Assessment of the removal of estrogenicity in biological nutrient removal wastewater treatment processes

    International Nuclear Information System (INIS)

    Ogunlaja, O.O.; Parker, W.J.

    2015-01-01

    The removal of estrogenicity in a University of Cape Town-biological nutrient removal (UCT-BNR) wastewater treatment process was investigated using pilot and bench scale systems, batch experiments and mathematical modeling. In the pilot BNR process, 96 ± 5% of the estrogenicity exerted by the influent wastewater was removed by the treatment process. The degradation efficiencies in the anaerobic, anoxic and aerobic zones of the pilot BNR bioreactor were 11 ± 9%, 18 ± 2% and 93 ± 10%, respectively. In order to further understand the performance of the BNR process in the removal of estrogenicity from wastewater, a bench scale BNR process was operated with synthetic wastewater dosed with E1 and E2. The removal of estrogenicity in the bench scale system (95 ± 5%) was comparable to the pilot BNR process and the degradation efficiencies were estimated to be 8 ± 0.8%, 38 ± 4% and 85 ± 22% in the anaerobic, anoxic and aerobic zones, respectively. A biotransformation model developed to predict the fate of E1 and E2 in batch tests using the sludge from the BNR process was calibrated using the data from the experiments. The biotransformation rate constants for the transformation of E2 to E1 were estimated as 71 ± 1.5, 31 ± 3.3 and 1 ± 0.9 L g COD −1 d −1 for the aerobic, anoxic and anaerobic batch tests, respectively, while the corresponding biotransformation rate constants for the transformation of E1 were estimated to be 7.3 ± 1.0, 3 ± 2.0, and 0.85 ± 0.6 L·g COD −1 d −1 . A steady state mass balance model formulated to describe the interactions between E2 and E1 in BNR activated sludge reasonably described the fate of E1 and E2 in the BNR process. - Highlights: • Comparable estrogenicity removal was observed from two BNR processes. • Pseudo first order model described the transformation of E2 and E1 in BNR process. • Biotransformation of E1 in BNR activated sludge controls the degradation of E2

  4. Assessment of the removal of estrogenicity in biological nutrient removal wastewater treatment processes

    Energy Technology Data Exchange (ETDEWEB)

    Ogunlaja, O.O., E-mail: oogunlaj@uwaterloo.ca; Parker, W.J., E-mail: wjparker@uwaterloo.ca

    2015-05-01

    The removal of estrogenicity in a University of Cape Town-biological nutrient removal (UCT-BNR) wastewater treatment process was investigated using pilot and bench scale systems, batch experiments and mathematical modeling. In the pilot BNR process, 96 ± 5% of the estrogenicity exerted by the influent wastewater was removed by the treatment process. The degradation efficiencies in the anaerobic, anoxic and aerobic zones of the pilot BNR bioreactor were 11 ± 9%, 18 ± 2% and 93 ± 10%, respectively. In order to further understand the performance of the BNR process in the removal of estrogenicity from wastewater, a bench scale BNR process was operated with synthetic wastewater dosed with E1 and E2. The removal of estrogenicity in the bench scale system (95 ± 5%) was comparable to the pilot BNR process and the degradation efficiencies were estimated to be 8 ± 0.8%, 38 ± 4% and 85 ± 22% in the anaerobic, anoxic and aerobic zones, respectively. A biotransformation model developed to predict the fate of E1 and E2 in batch tests using the sludge from the BNR process was calibrated using the data from the experiments. The biotransformation rate constants for the transformation of E2 to E1 were estimated as 71 ± 1.5, 31 ± 3.3 and 1 ± 0.9 L g COD{sup −1} d{sup −1} for the aerobic, anoxic and anaerobic batch tests, respectively, while the corresponding biotransformation rate constants for the transformation of E1 were estimated to be 7.3 ± 1.0, 3 ± 2.0, and 0.85 ± 0.6 L·g COD{sup −1} d{sup −1}. A steady state mass balance model formulated to describe the interactions between E2 and E1 in BNR activated sludge reasonably described the fate of E1 and E2 in the BNR process. - Highlights: • Comparable estrogenicity removal was observed from two BNR processes. • Pseudo first order model described the transformation of E2 and E1 in BNR process. • Biotransformation of E1 in BNR activated sludge controls the degradation of E2.

  5. Characteristics of BPA removal from water by PACl-Al13 in coagulation process.

    Science.gov (United States)

    Xiaoying, Ma; Guangming, Zeng; Chang, Zhang; Zisong, Wang; Jian, Yu; Jianbing, Li; Guohe, Huang; Hongliang, Liu

    2009-09-15

    This paper discussed the coagulation characteristics of BPA with polyaluminum chloride (PACl-Al(13)) as coagulant, examined the impact of coagulation pH, PACl-Al(13) dosage, TOC (total organic carbon) and turbidity on BPA removal, and analyzed the possible dominant mechanisms in water coagulation process. Formation and performance of flocs during coagulation processes were monitored using photometric dispersion analyzer (PDA). When the concentration of humic acid matters and turbidity was low in the solution, the experimental results showed that the removal of BPA experienced increase and subsequently decrease with the PACl-Al(13) dosage increasing. The optimal PACl-Al(13) dosage was found at BPA/PACl-Al(13)=1:2.6(M/M) under our experiment conditions. Results show that the maximum BPA removal efficiency occurred at pH 9.0 due to the adsorption by Al(13) aggregates onto BPA rather than charge neutralization mechanism by polynuclear aluminous salts in the solution. The humic acid matters and kaolin in the solution have significant effect on BPA removal with PACl-Al(13) in the coagulation. The BPA removal will be weakened at high humic matters. The removal rate of BPA increased and subsequently decreased with the turbidity increasing.

  6. Simultaneous Removal of Thallium and EDTA by Fenton Process

    Science.gov (United States)

    Xu, Ruibing; Huang, Xuexia; Li, Huosheng; Su, Minhua; Chen, Diyun

    2018-01-01

    The wastewater containing heavy metals and organic pollutants is widely discharged from industries. Because of the coexistence of heavy metals and organic pollutants, the treatment of such wastewater is very difficult. Fenton process is considered to be one of the most effective approaches for the degradation of organic pollutants in aqueous solution due to the strong oxidative ability of hydroxyl radical which generated from the Fenton process. Apart from this, heavy metals are able to be removed during Fenton process owning to the synergic effect of coagulation and precipitation. In this work, pollutants of thallium and EDTA were successfully removed via the Fenton process. A series of single-factor experiments were designed and performed to achieve an optimal reaction conditions for the removal of both thallium and EDTA. Results showed that the removal efficiencies of thallium and TOC could be as high as 96.54% and 70.42%, respectively. The outcomes from our study demonstrate that Fenton process is a promising method for the purification of wastewater containing thallium and EDTA.

  7. Ultrasound-assisted oxidative process for sulfur removal from petroleum product feedstock.

    Science.gov (United States)

    Mello, Paola de A; Duarte, Fábio A; Nunes, Matheus A G; Alencar, Mauricio S; Moreira, Elizabeth M; Korn, Mauro; Dressler, Valderi L; Flores, Erico M M

    2009-08-01

    A procedure using ultrasonic irradiation is proposed for sulfur removal of a petroleum product feedstock. The procedure involves the combination of a peroxyacid and ultrasound-assisted treatment in order to comply with the required sulfur content recommended by the current regulations for fuels. The ultrasound-assisted oxidative desulfurization (UAOD) process was applied to a petroleum product feedstock using dibenzothiophene as a model sulfur compound. The influence of ultrasonic irradiation time, oxidizing reagents amount, kind of solvent for the extraction step and kind of organic acid were investigated. The use of ultrasonic irradiation allowed higher efficiency for sulfur removal in comparison to experiments performed without its application, under the same reactional conditions. Using the optimized conditions for UAOD, the sulfur removal was about 95% after 9min of ultrasonic irradiation (20kHz, 750W, run at 40%), using hydrogen peroxide and acetic acid, followed by extraction with methanol.

  8. Removal of Heavy Metal Ions with Acid Activated Carbons Derived from Oil Palm and Coconut Shells

    Science.gov (United States)

    Rahman, Mokhlesur M.; Adil, Mohd; Yusof, Alias M.; Kamaruzzaman, Yunus B.; Ansary, Rezaul H.

    2014-01-01

    In this work, batch adsorption experiments were carried out to investigate the suitability of prepared acid activated carbons in removing heavy metal ions such as nickel(II), lead(II) and chromium(VI). Acid activated carbons were obtained from oil palm and coconut shells using phosphoric acid under similar activation process while the differences lie either in impregnation condition or in both pretreatment and impregnation conditions. Prepared activated carbons were modified by dispersing hydrated iron oxide. The adsorption equilibrium data for nickel(II) and lead(II) were obtained from adsorption by the prepared and commercial activated carbons. Langmuir and Freundlich models fit the data well. Prepared activated carbons showed higher adsorption capacity for nickel(II) and lead(II). The removal of chromium(VI) was studied by the prepared acid activated, modified and commercial activated carbons at different pH. The isotherms studies reveal that the prepared activated carbon performs better in low concentration region while the commercial ones in the high concentration region. Thus, a complete adsorption is expected in low concentration by the prepared activated carbon. The kinetics data for Ni(II), Pb(II) and Cr(VI) by the best selected activated carbon fitted very well to the pseudo-second-order kinetic model. PMID:28788640

  9. Removal of Heavy Metal Ions with Acid Activated Carbons Derived from Oil Palm and Coconut Shells

    Directory of Open Access Journals (Sweden)

    Mokhlesur M. Rahman

    2014-05-01

    Full Text Available In this work, batch adsorption experiments were carried out to investigate the suitability of prepared acid activated carbons in removing heavy metal ions such as nickel(II, lead(II and chromium(VI. Acid activated carbons were obtained from oil palm and coconut shells using phosphoric acid under similar activation process while the differences lie either in impregnation condition or in both pretreatment and impregnation conditions. Prepared activated carbons were modified by dispersing hydrated iron oxide. The adsorption equilibrium data for nickel(II and lead(II were obtained from adsorption by the prepared and commercial activated carbons. Langmuir and Freundlich models fit the data well. Prepared activated carbons showed higher adsorption capacity for nickel(II and lead(II. The removal of chromium(VI was studied by the prepared acid activated, modified and commercial activated carbons at different pH. The isotherms studies reveal that the prepared activated carbon performs better in low concentration region while the commercial ones in the high concentration region. Thus, a complete adsorption is expected in low concentration by the prepared activated carbon. The kinetics data for Ni(II, Pb(II and Cr(VI by the best selected activated carbon fitted very well to the pseudo-second-order kinetic model.

  10. Chloroacetic acids in environmental processes

    Czech Academy of Sciences Publication Activity Database

    Matucha, Miroslav; Gryndler, Milan; Forczek, Sándor; Uhlířová, H.; Fuksová, Květoslava; Schröder, P.

    2003-01-01

    Roč. 1, - (2003), s. 127-130 ISSN 1610-3653 R&D Projects: GA ČR GA522/02/0874 Institutional research plan: CEZ:AV0Z5038910 Keywords : Dichloroacetic acid * Trichloroacetic acid * Microbial degradation Subject RIV: GK - Forestry

  11. Removing and recovering of uranium from the acid mine waters by using ion exchange resin

    International Nuclear Information System (INIS)

    Nascimento, Marcos Roberto Lopes do

    1998-01-01

    Ion exchange using resins is one of the few processes capable of reducing ionic contaminants in effluents to very low levels. In this study the process was used to remove and recovery uranium from acid mine waters at Pocos de Caldas-MG Uranium Mining and Milling Plant. The local mineralogical features, allied to the biogeochemical phenomena, owing to presence of pyrite in the rock piles, moreover another factors, resulting acid drainage with several pollutants, including uranium ranging from 6 to 14 mg/l, as sulfate complex, that can be removed by anionic exchanger. The iron interference is eliminated by lime pretreatment of water, increasing pH from 2.6 to 3.3-3.8 to precipitate this cation, without changing the uranium amount. Eight anionic resins were tested, based on the uranium loading, in sorption studies. Retention time, and pH influence was verified for the exchanger chose. With breakthrough of 1 mg U/L and 10 mg U/l in the feed solution, the uranium decontamination level was 94%. Typical values of loading resin were 20-30 g U/l and 70-90 g SO 4 /l. Uranium elution was done with Na Cl solution. Retention time, saline, and acid concentration were the parameters studied. The concentrate, obtained from the eluate by ammonia precipitation, presented uranium (86,8% as U 3 O 8 ) and impurities within commercial specifications. (author)

  12. Coagulation / flocculation process in the removal of trace metals ...

    African Journals Online (AJOL)

    Attempts were made in this study to examine the effectiveness of polymer addition to coagulation process during treatment of a beverage industrial wastewater to remove some of its trace metals content such as lead, cadmium, total iron, total chromium, nickel and zinc. Experiments were conducted using the standard Jar ...

  13. 27 CFR 19.381 - Removals from processing.

    Science.gov (United States)

    2010-04-01

    ... or further processing; (d) Spirits or wines for authorized voluntary destruction; or (e) Wines by transfer in bond to a bonded wine cellar or to another distilled spirits plant. However, wine may not be removed from the bonded premises of a distilled spirits plant for consumption or sale as wine. Spirits may...

  14. The use of Syrian bentonite to remove organics and other ions from commercial Syrian phosphoric acid

    International Nuclear Information System (INIS)

    Khorfan, S.; Abdulbaki, M.; Zein, A.

    2006-01-01

    Using of activated carbon to remove organic matter from phosphoric acid in uranium and P 2 O 5 extraction units has high cost. A new study was conducted to establish a new material instead of activated carbon. Experiments were carried out on removing organic matter by adsorption on Syrian bentonite. The experiments of the removal of humic acid by Syrian bentonite gave good results and showed that the chemical and thermal activation of bentonite increased the adsorption efficiency. (Authors)

  15. The use of Syrian bentonite to remove organics and other ions from commercial Syrian phosphoric acid

    International Nuclear Information System (INIS)

    Khorfan, S.; Abdulbaki, M.; Zein, A.

    2005-03-01

    Using of activated carbon to remove organic matter from phosphoric acid in uranium and P 2 O 5 extraction units has high cost. A new study was conducted to establish a new material instead of activated carbon. Experiments were carried out on removing organic matter by adsorption on Syrian bentonite. The experiments of the removal of humic acid by Syrian bentonite gave good results and showed that the chemical and thermal activation of bentonite increased the adsorption efficiency. (Authors)

  16. Removal of Aqueous Boron by Using Complexation of Boric Acid with Polyols: A Raman Spectroscopic Study

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Ki Heon; Jeong, Hui Cheol; An, Hye Young; Lim, Jun-Heok; Lee, Jea-Keun; Won, Yong Sun [Pukyong National University, Busan (Korea, Republic of)

    2015-12-15

    Boron is difficult to be removed from seawater by simple RO (reverse osmosis) membrane process, because the size of boric acid (B(OH){sub 3}), the major form of aqueous boron, is as small as the nominal pore size of RO membrane. Thus, the complexation of boric acid with polyols was suggested as an alternative way to increase the size of aqueous boron compounds and the complexation behavior was investigated with Raman spectroscopy. As a reference, the Raman peak for symmetric B-O stretching vibrational mode both in boric acid and borate ion (B(OH){sub 4}{sup -}) was selected. A Raman peak shift (877 cm{sup -1} →730 cm{sup -1}) was observed to confirm that boric acid in water is converted to borate ion as the pH increases, which is also correctly predicted by frequency calculation. Meanwhile, the Raman peak of borate ion (730 cm{sup -1}) did not appear as the pH increased when polyols were applied into aqueous solution of boric acid, suggesting that the boric acid forms complexing compounds by combining with polyols.

  17. Removal of enzymatic and fermentation inhibitory compounds from biomass slurries for enhanced biorefinery process efficiencies.

    Science.gov (United States)

    Gurram, Raghu N; Datta, Saurav; Lin, Yupo J; Snyder, Seth W; Menkhaus, Todd J

    2011-09-01

    Within the biorefinery paradigm, many non-monomeric sugar compounds have been shown to be inhibitory to enzymes and microbial organisms that are used for hydrolysis and fermentation. Here, two novel separation technologies, polyelectrolyte polymer adsorption and resin-wafer electrodeionization (RW-EDI), have been evaluated to detoxify a dilute acid pretreated biomass slurry. Results showed that detoxification of a dilute acid pretreated ponderosa pine slurry by sequential polyelectrolyte and RW-EDI treatments was very promising, with significant removal of acetic acid, 5-hydroxymethyl furfural, and furfural (up to 77%, 60%, and 74% removed, respectively) along with >97% removal of sulfuric acid. Removal of these compounds increased the cellulose conversion to 94% and elevated the hydrolysis rate to 0.69 g glucose/L/h. When using Saccharomyces cerevisiae D(5)A for fermentation of detoxified slurry, the process achieved 99% of the maximum theoretical ethanol yield and an ethanol production rate nearly five-times faster than untreated slurry. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Boron removal from aqueous solutions by activated carbon impregnated with salicylic acid

    International Nuclear Information System (INIS)

    Celik, Z. Ceylan; Can, B.Z.; Kocakerim, M. Muhtar

    2008-01-01

    In this study, the removal of boric acid from aqueous solution by activated carbon impregnated with salicylic acid was studied in batch system. pH, adsorbent amount, initial boron concentration, temperature, shaking rate and salicylic acid film thickness were chosen as parameters. Boron removal efficiencies increased with increasing adsorbent amount, temperature and pH, decreasing initial boron concentration. As thickness of salicylic acid film on activated carbon becomes thin up to 0.088 nm, the efficiency increased, and then, the efficiency decreased with becoming thinner than 0.088 nm of salicylic acid film. Shaking rate was no effect on removal efficiency. In result, it was determined that the use of salicylic acid as an impregnant for activated carbon led to the increase of the amount of boron adsorbed. A lactone ring, being the most appropriate conformation, forms between boric acid and -COOH and -OH groups of salicylic acid

  19. Boron removal from aqueous solutions by activated carbon impregnated with salicylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Z. Ceylan [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey)], E-mail: zcelik@atauni.edu.tr; Can, B.Z. [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey); Kocakerim, M. Muhtar [Department of Chemical Engineering, Atatuerk University, Faculty of Engineering, 25240 Erzurum (Turkey)

    2008-03-21

    In this study, the removal of boric acid from aqueous solution by activated carbon impregnated with salicylic acid was studied in batch system. pH, adsorbent amount, initial boron concentration, temperature, shaking rate and salicylic acid film thickness were chosen as parameters. Boron removal efficiencies increased with increasing adsorbent amount, temperature and pH, decreasing initial boron concentration. As thickness of salicylic acid film on activated carbon becomes thin up to 0.088 nm, the efficiency increased, and then, the efficiency decreased with becoming thinner than 0.088 nm of salicylic acid film. Shaking rate was no effect on removal efficiency. In result, it was determined that the use of salicylic acid as an impregnant for activated carbon led to the increase of the amount of boron adsorbed. A lactone ring, being the most appropriate conformation, forms between boric acid and -COOH and -OH groups of salicylic acid.

  20. Silver removal process development for the MEO cleanout

    International Nuclear Information System (INIS)

    Hsu, P.C.; Chiba, Z.; Schumacher, B.J.; Murguia, L.C.; Adamson, M.G.

    1996-02-01

    The Mediated Electrochemical Oxidation (MEO) system is an aqueous process which treats low-level mixed wastes by oxidizing the organic components of he waste into carbon dioxide and water. As MEO system continues to run, dissolved ash and radionuclides slowly accumulate in the anolyte and must be removed to maintain process efficiency. At such time, all of the anolyte is pumped into a still feed tank, and the silver ions need to be removed before sending the solution to a thin-film evaporator for further concentration. The efficiency of removing silver ions in the solution needs to be high enough such that the residual silver sent to Final Forms would be less than 1% wt. The purpose of this work is to develop an efficient process to remove silver ions during the MEO cleanout and to demonstrate the capability of centrifugation for separating small silver chloride particles from the solution. This development work includes lab scale experiments and bench scale tests. This report summarizes the results

  1. Removal of the antiviral agent oseltamivir and its biological activity by oxidative processes

    International Nuclear Information System (INIS)

    Mestankova, Hana; Schirmer, Kristin; Escher, Beate I.; Gunten, Urs von

    2012-01-01

    The antiviral agent oseltamivir acid (OA, the active metabolite of Tamiflu ® ) may occur at high concentrations in wastewater during pandemic influenza events. To eliminate OA and its antiviral activity from wastewater, ozonation and advanced oxidation processes were investigated. For circumneutral pH, kinetic measurements yielded second-order rate constants of 1.7 ± 0.1 × 10 5 and 4.7 ± 0.2 × 10 9 M −1 s −1 for the reaction of OA with ozone and hydroxyl radical, respectively. During the degradation of OA by both oxidants, the antiviral activity of the treated aqueous solutions was measured by inhibition of neuraminidase activity of two different viral strains. A transient, moderate (two-fold) increase in antiviral activity was observed in solutions treated up to a level of 50% OA transformation, while for higher degrees of transformation the activity corresponded to that caused exclusively by OA. OA was efficiently removed by ozonation in a wastewater treatment plant effluent, suggesting that ozonation can be applied to remove OA from wastewater. - Highlights: ► Oseltamivir acid (OA) is oxidized by ozone and hydroxyl radical. ► Kinetics: We determined rate constants for the reaction with these oxidants. ► The specific activity of OA as neuraminidase inhibitor disappeared during oxidation. ► Ozonation and advanced oxidation can effectively remove OA from wastewaters. - Ozone and hydroxyl radical treatment processes can degrade aqueous oseltamivir acid and remove its antiviral activity.

  2. Metal chelate process to remove pollutants from fluids

    Science.gov (United States)

    Chang, S.G.T.

    1994-12-06

    The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO[sub x] and optionally SO[sub 2] from a fluid using a metal ion (Fe[sup 2+]) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution. 26 figures.

  3. Organic pollutant removal from edible oil process wastewater using electrocoagulation

    Science.gov (United States)

    Sharma, S.; Can, O. T.; Hammed, M.; Nawarathna, D.; Simsek, H.

    2018-03-01

    Wastewaters generated from vegetable oil industries contain a high concentration of organic pollutants that are detrimental to the aquatic ecosystem. Electrochemical processes are gaining importance in the treatment of inorganic and resistant organic pollutants in wastewaters. In this study, electrocoagulation (EC) was applied to remove organic pollutants and oil and grease from canola oil wastewater using aluminum (Al) and iron (Fe) electrodes. The application of EC in the wastewater achieved more than 80% removal of organic carbon and nearly 100% removal of suspended solids (SS). The effectiveness of EC is influenced mainly by current density, pH, electrolyte (NaCl), electrode contact time and electrode type. It was observed that Al electrode combination yielded better removal at a lesser time compared to that of Fe electrodes. However, varying current densities had its significance in terms of coagulation time only. Increase in current density achieved decrease in coagulation time. Both Al and Fe could remove between 52-59% of oil and grease from canola oil wastewater

  4. Removal of nalidixic acid and its degradation products by an integrated MBR-ozonation system.

    Science.gov (United States)

    Pollice, A; Laera, G; Cassano, D; Diomede, S; Pinto, A; Lopez, A; Mascolo, G

    2012-02-15

    Chemical-biological degradation of a widely spread antibacterial (nalidixic acid) was successfully obtained by an integrated membrane bioreactor (MBR)-ozonation process. The composition of the treated solution simulated the wastewater from the production of the target pharmaceutical, featuring high salinity and a relevant concentration of sodium acetate. Aim of treatment integration was to exploit the synergistic effects of chemical oxidation and bioprocesses, by adopting the latter to remove most of the COD and the ozonation biodegradable products. Integration was achieved by placing ozonation in the recirculation stream of the bioreactor effluent. The recirculation flow rate was three-fold the MBR feed, and the performance of the integrated system was compared to the standard polishing configuration (single ozonation step after the MBR). Results showed that the introduction of the ozonation step did not cause relevant drawbacks to both biological and filtration processes. nalidixic acid passed undegraded through the MBR and was completely removed in the ozonation step. Complete degradation of most of the detected ozonation products was better achieved with the integrated MBR-ozonation process than using the sequential treatment configuration, i.e. ozone polishing after MBR, given the same ozone dosage. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID REMOVAL

    Energy Technology Data Exchange (ETDEWEB)

    Gary M. Blythe

    2004-01-01

    The objective of this project has been to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The project was co-funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-99FT40718, along with EPRI, the American Electric Power Company (AEP), FirstEnergy Corporation, the Tennessee Valley Authority, and Carmeuse North America. Sulfuric acid controls are becoming of increased interest for coal-fired power generating units for a number of reasons. In particular, sulfuric acid can cause plant operation problems such as air heater plugging and fouling, back-end corrosion, and plume opacity. These issues will likely be exacerbated with the retrofit of selective catalytic reduction (SCR) for NOX control, as SCR catalysts are known to further oxidize a portion of the flue gas SO{sub 2} to SO{sub 3}. The project tested the effectiveness of furnace injection of four different magnesium-based or dolomitic alkaline sorbents on full-scale utility boilers. These reagents were tested during one- to two-week tests conducted on two FirstEnergy Bruce Mansfield Plant (BMP) units. One of the sorbents tested was a magnesium hydroxide slurry byproduct from a modified Thiosorbic{reg_sign} Lime wet flue gas desulfurization process. The other three sorbents are available commercially and include dolomite, pressure-hydrated dolomitic lime, and commercially available magnesium hydroxide. The dolomite reagent was injected as a dry powder through out-of-service burners. The other three reagents were injected as slurries through air-atomizing nozzles inserted through the front wall of the upper furnace. After completing the four one- to two-week tests, the most promising sorbents were selected for longer-term (approximately 25-day) full-scale tests on two different units. The longer-term tests were conducted to confirm sorbent effectiveness over extended operation on two

  6. Phosphoric acid activation of sugarcane bagasse for removal of o-toluidine and benzidine

    Science.gov (United States)

    Adib, M. R. M.; Attahirah, M. H. M. N.; Amirza, A. R. M.

    2018-04-01

    In the effort to find alternatives for low cost adsorbent, activated carbon using sugarcane bagasse (SBAC) has been introduced in this study that has undergo chemical treatment using phosphoric acid to determine the effectiveness of adsorption process in removing o-toluidine and benzidine. Throughout this study, 92.9% of o-toluidine has been successfully removed by SBAC at optimum value of 1.1 g of dosage with contact time of 10 minutes and concentration of 10 mg/L. While benzidine was remove by 83.1% at optimum dosage of 1.1 g with 60 minutes of contact time and at 20 mg/L concentrations. Testing of SEM proves that SBAC has high porosity and comparable to CAC. In FTIR results, shows that CAC has high number of double bond while SBAC shows no double bond at all. Presence of double bond in CAC lead to increase in percentage of removal of adsorbate. After considering other factor such as cost, energy and environmental friendly, it shows that SBAC was considerable to replaced CAC.

  7. Removal of colour and COD from wastewater containing acid blue 22 by electrochemical oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Panizza, Marco [Dipartimento di Ingegneria Chimica e di Processo ' G.B. Bonino' , Universita degli Studi di Genova, p.le J.F. Kennedy 1, 16129 Genova (Italy)], E-mail: marco.panizza@unige.it; Cerisola, Giacomo [Dipartimento di Ingegneria Chimica e di Processo ' G.B. Bonino' , Universita degli Studi di Genova, p.le J.F. Kennedy 1, 16129 Genova (Italy)

    2008-05-01

    Electrochemical oxidation of synthetic wastewater containing acid blue 22 on a boron-doped diamond electrode (BDD) was studied, using cyclic voltammetry and bulk electrolysis. The influence of current density, dye concentration, flow rate, and temperature was investigated, in order to find the best conditions for COD and colour removal. It was found that, during oxidation, a polymeric film, causing BDD deactivation, was formed in the potential region of water stability, and that it was removed by anodic polarisation at high potentials in the region of O{sub 2} evolution. Bulk electrolysis results showed that the electrochemical process was suitable for completely removing COD and effectively decolourising wastewaters, due to the production of hydroxyl radicals on the diamond surface. In particular, under optimal experimental conditions of flow rates (i.e. 300 dm{sup 3} h{sup -1}) and current density (i.e. 20 mA cm{sup -2}), 97% of COD was removed in 12 h electrolysis, with 70 kWh m{sup -3}energy consumption.

  8. Removal of colour and COD from wastewater containing acid blue 22 by electrochemical oxidation

    International Nuclear Information System (INIS)

    Panizza, Marco; Cerisola, Giacomo

    2008-01-01

    Electrochemical oxidation of synthetic wastewater containing acid blue 22 on a boron-doped diamond electrode (BDD) was studied, using cyclic voltammetry and bulk electrolysis. The influence of current density, dye concentration, flow rate, and temperature was investigated, in order to find the best conditions for COD and colour removal. It was found that, during oxidation, a polymeric film, causing BDD deactivation, was formed in the potential region of water stability, and that it was removed by anodic polarisation at high potentials in the region of O 2 evolution. Bulk electrolysis results showed that the electrochemical process was suitable for completely removing COD and effectively decolourising wastewaters, due to the production of hydroxyl radicals on the diamond surface. In particular, under optimal experimental conditions of flow rates (i.e. 300 dm 3 h -1 ) and current density (i.e. 20 mA cm -2 ), 97% of COD was removed in 12 h electrolysis, with 70 kWh m -3 energy consumption

  9. An innovative carbonate coprecipitation process for the removal of zinc and manganese from mining impacted waters

    Science.gov (United States)

    Sibrell, P.L.; Chambers, M.A.; Deaguero, A.L.; Wildeman, T.R.; Reisman, D.J.

    2007-01-01

    Although mine drainage is usually thought of as acidic, there are many cases where the water is of neutral pH, but still contains metal species that can be harmful to human or aquatic animal health, such as manganese (Mn) and zinc (Zn). Typical treatment of mine drainage waters involves pH adjustment, but this often results in excessive sludge formation and removal of nontoxic species such as magnesium and calcium. Theoretical consideration of the stability of metal carbonate species suggests that the target metals could be removed from solution by coprecipitation with calcium carbonate. The U.S. Geological Survey has developed a limestone-based process for remediation of acid mine drainage that increases calcium carbonate saturation. This treatment could then be coupled with carbonate coprecipitation as an innovative method for removal of toxic metals from circumneutral mine drainage waters. The new process was termed the carbonate coprecipitation (CCP) process. The CCP process was tested at the laboratory scale using a synthetic mine water containing 50 mg/L each of Mn and Zn. Best results showed over 95% removal of both Mn and Zn in less than 2 h of contact in a limestone channel. The process was then tested on a sample of water from the Palmerton zinc superfund site, near Palmerton, Pennsylvania, containing over 300 mg/L Zn and 60 mg/L Mn. Treatment of this water resulted in removal of over 95% of the Zn and 40% of the Mn in the limestone channel configuration. Because of the potential economic advantages of the CCP process, further research is recommended for refinement of the process for the Palmerton water and for application to other mining impacted waters as well. ?? Mary Ann Liebert, Inc.

  10. A process for uranium recovery in phosphoric acid

    International Nuclear Information System (INIS)

    Duarte Neto, J.

    1984-01-01

    Results are presented about studies carried out envisaging the development of a process for uranium recovery from phosphoric acid, produced from the concentrate obtained from phosphorus-uraniferous mineral from Itataia mines (CE, Brazil). This process uses a mixture of DEPA-TOPO as extractant and the extraction cycle involves the following stages: acid pre-treatment; adjustment of the oxidation potential so to ensure that all uranium is hexavalent; extraction of uranium from the acid; screening of the solvent to remove undesirable impurities; uranium re-extraction and precipitation; solvent recovery. A micro-pilot plant for continuous processing was built up. Data collected showed that uranium can be recovered with an yield greater than 99%, thus proving the feasibility of the process and encouraging the construction of a bigger scale plant. (Author) [pt

  11. Cyanide removal by combined adsorption and biodegradation process

    Directory of Open Access Journals (Sweden)

    R. Roshan Dash, Ch. Balomajumder, A. Kumar

    2006-04-01

    Full Text Available Investigation of the effectiveness of simultaneous adsorption and biodegradation (SAB process over individual processes by using microbes Rhizopus oryzae and Stemphylium loti with granular activated carbon (GAC as adsorbent was carried out. The maximum removal efficiency of cyanide had been achieved by biodegradation alone was 83% by R. oryzae, while it was 90% by S. loti at initial pH of 5.6 and 7.2 respectively and at initial CN- concentration of 150 mg/L. In the combined process efficiency of R. oryzae closer to S. loti (95.3% and 98.6% respectively

  12. Wastewater treatment processes for the removal of emerging organic pollutants

    Directory of Open Access Journals (Sweden)

    Ainhoa Rubio Clemente

    2013-12-01

    Full Text Available Emerging organic pollutants form a very heterogeneous group of substances that have negative effects on aquatic organisms, so they should be removed from the environment. Unfortunately, conventional processes in wastewater treatment plants, especially biological ones, are inefficient in the degradation of these substances. It is therefore necessary to evaluate and optimize the effectiveness of the treatments, including advanced oxidation and membrane filtration processes. However, both techniques have drawbacks that may limit their stand-alone application, so it is proposed that the best solution may be to combine these technologies with biological processes to treat wastewater contaminated with emerging organic pollutants.

  13. On-line removal of volatile fatty acids from CELSS anaerobic bioreactor via nanofiltration.

    Science.gov (United States)

    Colon, G; Sager, J C

    2001-01-01

    The CELSS resource recovery system, which is a waste-processing system, uses aerobic and anaerobic bioreactors to recover plants nutrients and secondary foods from the inedible biomass. The anaerobic degradation of the inedible biomass, by means of culture of rumen bacteria, generates organic compounds such as volatile fatty acids (VFA) (acetic, propionic, butyric) and ammonia. The presence of VFA in the bioreactor medium at fairly low concentrations decreases the microbial population's metabolic reactions due to end-product inhibition. Technologies to remove VFA continuously from the bioreactor are of high interest. Several candidate technologies were analyzed, such as organic solvent liquid-liquid extraction, adsorption and/or ion exchange, dialysis, electrodialysis, and pressure-driven membrane separation processes. The proposed technique for the on-line removal of VFA from the anaerobic bioreactor was a nanofiltration membrane recycle bioreactor. In order to establish the nanofiltration process performance variables before coupling it to the bioreactor, a series of experiments was carried out using a 10,000 molecular weight cutoff (MWCO) tubular ceramic membrane module. The variables studied were the bioreactor slurry permeation characteristics, such as: the permeate flux, VFA and nutrient removal rates as a function of applied transmembrane pressure, fluid recirculation velocity, suspended matter concentration, and process operating time. Results indicated that the permeate flux, VFA, and nutrients removal rates are directly proportional to the fluid recirculation velocity in the range between 0.6 and 1.0 m/s, applied pressure when these are lower than 1.5 bar, and inversely proportional to the total suspended solids concentration in the range between 23,466 and 34,880 mg/L. At applied pressure higher than 1.5 bar the flux is not more linearly dependent due to concentration polarization and fouling effects over the membrane surface. It was also found that the

  14. On-line removal of volatile fatty acids from CELSS anaerobic bioreactor via nanofiltration

    Science.gov (United States)

    Colon, Guillermo

    1995-01-01

    The CELSS (controlled ecological life support system) resource recovery system, which is a waste processing system, uses aerobic and anaerobic bioreactors to recover plants nutrients and secondary foods from the inedible biomass. The anaerobic degradation of the inedible biomass by means of culture of rumen bacteria,generates organic compounds such as volatile fatty acids (acetic, propionic, butyric, VFA) and ammonia. The presence of VFA in the bioreactor medium at fairly low concentrations decreases the microbial population's metabolic reactions due to end-product inhibition. Technologies to remove VFA continuously from the bioreactor are of high interest. Several candidate technologies were analyzed, such as organic solvent liquid-liquid extraction, adsorption and/or ion exchange, dialysis, electrodialysis, and pressure driven membrane separation processes. The proposed technique for the on-line removal of VFA from the anaerobic bioreactor was a nanofiltration membrane recycle bioreactor. In order to establish the nanofiltration process performance variables before coupling it to the bioreactor, a series of experiments were carried out using a 10,000 MWCO tubular ceramic membrane module. The variables studied were the bioreactor slurry permeation characteristics, such as, the permeate flux, VFA and the nutrient removal rates as a function of applied transmembrane pressure, fluid recirculation velocity, suspended matter concentration, and process operating time. Results indicate that the permeate flux, VFA and nutrients removal rates are directly proportional to the fluid recirculation velocity in the range between 0.6 to 1.0 m/s, applied pressure when these are low than 1.5 bar, and inversely proportional to the total suspended solids concentration in the range between 23,466 to 34,880. At applied pressure higher than 1.5 bar the flux is not more linearly dependent due to concentration polarization and fouling effects over the membrange surface. It was also found

  15. Color, TOC and AOX removals from pulp mill effluent by advanced oxidation processes: A comparative study

    International Nuclear Information System (INIS)

    Catalkaya, Ebru Cokay; Kargi, Fikret

    2007-01-01

    Pulp mill effluent containing toxic chemicals was treated by different advanced oxidation processes (AOPs) consisting of treatments by hydrogen peroxide, Fenton's reagent (H 2 O 2 /Fe 2+ ), UV, UV/H 2 O 2 , photo-Fenton (UV/H 2 O 2 /Fe 2+ ), ozonation and peroxone (ozone/H 2 O 2 ) in laboratory-scale reactors for color, total organic carbon (TOC) and adsorbable organic halogens (AOX) removals from the pulp mill effluent. Effects of some operating parameters such as the initial pH, oxidant and catalyst concentrations on TOC, color, AOX removals were investigated. Almost every method used resulted in some degree of color removal from the pulp mill effluent. However, the Fenton's reagent utilizing H 2 O 2 /Fe 2+ resulted in the highest color, TOC and AOX removals under acidic conditions when compared with the other AOPs tested. Approximately, 88% TOC, 85% color and 89% AOX removals were obtained by the Fenton's reagent at pH 5 within 30 min. Photo-Fenton process yielded comparable TOC (85%), color (82%) and AOX (93%) removals within 5 min due to oxidations by UV light in addition to the Fenton's reagent. Fast oxidation reactions by the photo-Fenton treatment makes this approach more favorable as compared to the others used

  16. Feasibility study of NaOH regeneration in acid gas removal unit using membrane electrolysis

    Science.gov (United States)

    Taufany, Fadlilatul; Pratama, Alvian; Romzuddin, Muhammad

    2017-05-01

    The world's energy demand is increasing with the development of human civilization. Due to limited energy resource, after 2020 fossil fuels thus is predicted will be replaced by renewable resources. Taking an example, one of the potential renewable energy to be considered is biogas, as its high content of methane, which can be produced via the fermentation process of the organic compounds under controlled anaerobic environment by utilizing the methanogen bacteria. However, prior the further use, this biogas must be purified from its impurities contents, i.e. acid gas of CO2 and H2S, up to 4% and 16 ppmv, respectively, in the acid gas removal unit. This such of purification efforts, will significantly increase the higher heating value of biogas, approximately from 600 to 900 Btu/Scf. During the purification process in this acid gas removal unit, NaOH solution is used as a liquid absorbent to reduce those acid gases content, in which the by-product of alkali salt (brine) was produced as waste. Here we report the feasibility study of the NaOH regeneration process in acid gas removal unit via membrane electrolysis technology, in which both the technical and economic aspects are taken account. To be precise in procedure, the anode semi-cell was filled with the brine solution, while the cathode semi-cell was filled with demineralized water, and those electrodes were separated by the cation exchange membrane. Furthermore, the applied potential was varied ranging from 5, 10, 15 and to 20 V, while the concentration of KCl electrolyte solutions were varied ranging from 0.01, 0.05, 0.1, and to 0.03 M. This study was conducted under controlled temperatures of 30 and 50 °C. Here we found that the % sodium recovery was increased along with the applied potential, temperature, and the decrease in KCl electrolyte concentration. We found that the best results, by means of the highest % sodium recovery, i.e. 97.26 %, was achieved under the experimental condition of temperature at 30

  17. Process for removing sulfate anions from waste water

    Science.gov (United States)

    Nilsen, David N.; Galvan, Gloria J.; Hundley, Gary L.; Wright, John B.

    1997-01-01

    A liquid emulsion membrane process for removing sulfate anions from waste water is disclosed. The liquid emulsion membrane process includes the steps of: (a) providing a liquid emulsion formed from an aqueous strip solution and an organic phase that contains an extractant capable of removing sulfate anions from waste water; (b) dispersing the liquid emulsion in globule form into a quantity of waste water containing sulfate anions to allow the organic phase in each globule of the emulsion to extract and absorb sulfate anions from the waste water and (c) separating the emulsion including its organic phase and absorbed sulfate anions from the waste water to provide waste water containing substantially no sulfate anions.

  18. Mesocosm studies to assess acidity removal from acidic mine lakes through controlled eutrophication

    International Nuclear Information System (INIS)

    Fyson, A.; Nixdorf, B.; Kalin, M.; Steinberg, C.E.W.

    1998-01-01

    Flooded lignite pits (Tagebaurestseen) in Lusatia, Germany, are acidic (pH 2.5-4) with high concentrations of iron. Mesocosms (total volume 20 l) were set up with water and sediment from a Tagebaurestsee to assess the effects of phosphate and organic amendments under natural light and low temperature. Chemical and biological parameters were observed over a 9-month period. Phosphate rock addition resulted in sustained reduction in acidity in the water column and induced the growth of Chlamydomonas spp. (Chlorophyceae) near the water surface and Lepocinclis teres (Euglenophyceae) in a band above the sediment. Addition of potatoes to mesocosms resulted in the generation of near-anoxic conditions above the sediment, and phosphorus, ammonium and carbon (organic and inorganic) were released as the potatoes decomposed. A pH > 6 was attained with 5.1 g (dry weight) of potatoes and pH > 8 with 34 g (dry weight). In both mesocosms, more than 90% of total acidity was removed

  19. Removal of disinfection by-product precursors by coagulation and an innovative suspended ion exchange process.

    Science.gov (United States)

    Metcalfe, David; Rockey, Chris; Jefferson, Bruce; Judd, Simon; Jarvis, Peter

    2015-12-15

    This investigation aimed to compare the disinfection by-product formation potentials (DBPFPs) of three UK surface waters (1 upland reservoir and 2 lowland rivers) with differing characteristics treated by (a) a full scale conventional process and (b) pilot scale processes using a novel suspended ion exchange (SIX) process and inline coagulation (ILCA) followed by ceramic membrane filtration (CMF). Liquid chromatography-organic carbon detection analysis highlighted clear differences between the organic fractions removed by coagulation and suspended ion exchange. Pretreatments which combined SIX and coagulation resulted in significant reductions in dissolved organic carbon (DOC), UV absorbance (UVA), trihalomethane and haloacetic acid formation potential (THMFP, HAAFP), in comparison with the SIX or coagulation process alone. Further experiments showed that in addition to greater overall DOC removal, the processes also reduced the concentration of brominated DBPs and selectively removed organic compounds with high DBPFP. The SIX/ILCA/CMF process resulted in additional removals of DOC, UVA, THMFP, HAAFP and brominated DBPs of 50, 62, 62, 62% and 47% respectively compared with conventional treatment. Copyright © 2015. Published by Elsevier Ltd.

  20. Process for removal of sulfur oxides from hot gases

    International Nuclear Information System (INIS)

    Bauerle, G. L.; Kohl, A. L.

    1984-01-01

    A process for the removal of sulfur oxides from two gas streams containing the same. One gas stream is introduced into a spray dryer zone and contacted with a finely dispersed spray of an aqueous medium containing an absorbent for sulfur oxides. The aqueous medium is introduced at a controlled rate so as to provide water to the gas in an amount to produce a cooled product gas having a temperature at least 7 0 C. above its adiabatic saturation temperature and from about 125-300% of the stoichiometric amount of absorbent required to react with the sulfur oxides to be removed from the gas stream. The effluent from the spray dryer zone comprises a gas stream of reduced sulfur oxide content and contains entrained dry particulate reaction products including unreacted absorbent. This gas stream is then introduced into a particulate removal zone from which is withdrawn a gas stream substantially free of particles and having a reduced sulfur oxide content. the dry particulate reaction products are collected and utilized as a source of absorbent for a second aqueous scrubbing medium containing unreacted absorbent for the sulfur oxides. An effluent gas stream is withdrawn from the aqueous scrubbing zone and comprises a water-saturated gas stream of reduced sulfur oxide content and substantially free of particles. The effluent gas streams from the particulate removal zone and the aqueous scrubbing zone are combined in such proportions that the combined gas stream has a temperature above its adiabatic saturation temperature

  1. Sulfates removal by the GYP-CIX process following lime treatment

    International Nuclear Information System (INIS)

    Robertson, A.M.; Everett, D.J.; Plessis, N.J. Du

    1994-01-01

    The treatment of acid mine drainage by limiting results in the discharge of water saturated in gypsum and containing residual metal concentrations. These waters may exceed drinking and irrigation water standards for TDS, sulfates and some metals. The scaling nature of the saturated gypsum solution makes it unsuitable for industrial use and makes further processing difficult and costly. This paper discusses a novel ion exchange process that is suitable to desalinate large volumes of mine and industrial waters with a TDS of up to 6,500 mg/l which is also high in calcium and sulfates, to meet effluent discharge specifications. The GYP-CIX process is a continuous fluidized bed ion-exchange process that effectively removes calcium sulfate from gypsum saturated waters. It uses low cost chemicals such as lime and sulfuric acid for resin regeneration. The only waste product is gypsum and the treated water produced meets standards for reuse or discharge. This process consists of a two stage operation. The first is the removal of cations in a multistage continuous loading train, using cation exchange resin. The second operation is the removal of anions, again in a multistage continuous loading train using anion exchange resin

  2. Selective removal of lanthanides from natural waters, acidic streams and dialysate

    Energy Technology Data Exchange (ETDEWEB)

    Yantasee, Wassana, E-mail: wassana.yantasee@pnl.gov [Pacific Northwest National Laboratory (PNNL), P.O. Box 999, Richland, WA 99352 (United States); Fryxell, Glen E.; Addleman, R. Shane; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya [Pacific Northwest National Laboratory (PNNL), P.O. Box 999, Richland, WA 99352 (United States); Xu Jide; Raymond, Kenneth N. [Chemistry Department, University of California, Berkeley, CA 94720 (United States); LBNL, Berkeley, CA 94720 (United States)

    2009-09-15

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS{sup TM}), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 {mu}g/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning.

  3. Selective removal of lanthanides from natural waters, acidic streams and dialysate

    International Nuclear Information System (INIS)

    Yantasee, Wassana; Fryxell, Glen E.; Addleman, R. Shane; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu Jide; Raymond, Kenneth N.

    2009-01-01

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS TM ), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 μg/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning.

  4. Denitrifying sulfide removal process on high-salinity wastewaters.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Chaocheng; Wang, Aijie; Guo, Yadong; Lee, Duu-Jong

    2015-08-01

    Denitrifying sulfide removal (DSR) process comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide, and acetate into nitrogen gas, elemental sulfur (S(0)), and carbon dioxide, respectively. Sulfide- and nitrate-laden wastewaters at 2-35 g/L NaCl were treated by DSR process. A C/N ratio of 3:1 was proposed to maintain high S(0) conversion rate. The granular sludge with a compact structure and smooth outer surface was formed. The microbial communities of DSR consortium via high-throughput sequencing method suggested that salinity shifts the predominating heterotrophic denitrifiers at 10 g/L NaCl.

  5. Removal of Arsenic Using Acid/Metal-Tolerant Sulfate Reducing Bacteria: A New Approach for Bioremediation of High-Arsenic Acid Mine Waters

    Directory of Open Access Journals (Sweden)

    Jennyfer Serrano

    2017-12-01

    Full Text Available Fluvial sediments, soils, and natural waters in northern Chile are characterized by high arsenic (As content. Mining operations in this area are potential sources of As and other metal contaminants, due to acid mine drainage (AMD generation. Sulfate Reducing Bacteria (SRB has been used for the treatment of AMD, as they allow for the reduction of sulfate, the generation of alkalinity, and the removal of dissolved heavy metals and metalloids by precipitation as insoluble metal sulfides. Thus, SRB could be used to remove As and other heavy metals from AMD, however the tolerance of SRB to high metal concentrations and low pH is limited. The present study aimed to quantify the impact of SRB in As removal under acidic and As-Fe-rich conditions. Our results show that SRB tolerate low pH (up to 3.5 and high concentrations of As (~3.6 mg·L−1. Batch experiments showed As removal of up to 73%, Iron (Fe removal higher than 78% and a neutralization of pH from acidic to circum-neutral conditions (pH 6–8. In addition, XRD analysis showed the dominance of amorphous minerals, while Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM-EDX analysis showed associations between As, Fe, and sulfur, indicating the presence of Fe-S-As compounds or interaction of As species with amorphous and/or nanocrystalline phases by sorption processes. These results indicate that the As removal was mediated by acid/metal-tolerant SRB and open the potential for the application of new strains of acid/metal-tolerant SRB for the remediation of high-As acid mine waters.

  6. Evaluation of Fenton Process in Removal of Direct Red 81

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Baghapour

    2016-01-01

    Full Text Available Background: Dyes are visible materials and are considered as one of the hazardous components that make up the industrial waste. Dye compounds in natural water, even in very low concentrations, will lead to environmental problems. Azo dyes are compounds with one or more –N=N– groups and are used in textile industry. Because of its low price, solubility, and stability, azo dyes are widely used in the textile industry. Direct Red 81 (DR81 is one of the azo dyes, which is removed from bodies of water, using various methods. This study aimed to assess DR81 dye removal by Fenton oxidation and the effects of various parameters on this process. Methods: Decolorization tests by Fenton oxidation were performed at dye concentrations of 50, 500, 100 and 1000 mg/L; hydrogen peroxide concentrations of 0, 10, 30, 60 and 120 mg/L; iron (II sulfate heptahydrate concentrations of 0, 3, 5, 20 and 50 mg/L; and pH levels of 3, 5, 7 and 10 for durations of 5, 10, 20, 30, 60 and 180 minutes. Results: The optimal condition occurred at a dye concentration of 20 mg/L, hydrogen peroxide concentration of 120 mg/L, bivalent iron concentration of 100 mg/L, pH of 3, and duration of 30 minutes. Under such conditions, the maximum dye removal rate was 88.98%. Conclusion: The results showed that DR81 could be decomposed and removed by Fenton oxidation. In addition, the removal of Direct Red 81 (DR81 depends on several factors such as dye concentration, reaction time, concentrations of hydrogen peroxide and iron, and pH

  7. Removal of Cu(II) from acidic electroplating effluent by biochars generated from crop straws.

    Science.gov (United States)

    Tong, Xuejiao; Xu, Renkou

    2013-04-01

    The removal efficiency of copper (Cu(II)) from an actual acidic electroplating effluent by biochars generated from canola, rice, soybean and peanut straws was investigated. The biochars simultaneously removed Cu(II) from the effluent, mainly through the mechanisms of adsorption and precipitation, and neutralized its acidity. The removal efficiency of Cu(II) by the biochars followed the order: peanut straw char > soybean straw char > canola straw char > rice straw char > a commercial activated carbonaceous material, which is consistent with the alkalinity of the biochars. The pH of the effluent was a key factor determining the removal efficiency of Cu(II) by biochars. Raising the initial pH of the effluent enhanced the removal of Cu(II) from it. The optimum pyrolysis temperature was 400 degrees C for producing biochar from crop straws for acidic wastewater treatment, and the optimum reaction time was 8 hr.

  8. Use of advanced oxidation processes for removal of micropollutants

    DEFF Research Database (Denmark)

    Madsen, Henrik Tækker; Søgaard, Erik Gydesen

    photocatalysis when illuminated with UV light, and it may furthermore be arranged so the photocatalyst is immobilized on the UV quartz tubes by coating, which removes the need for a constant addition and subsequent removal of TiO2 to the system. The effect of the current system, and the TiO2 modified system...... was investigated by degradation of the synthetic estrogen 17α-ethinylestradiol (EE2). EE2 was used as the model compound since it is a very potent endocrine disruptor that has been found to have endocrine effects on fish at ppt levels. Also, the disinfection capability with photocatalysis was investigated...... of the microorganisms, photocatalysis works by oxidizing the cell membrane for microorganism adsorbed to the coated surface, which is a more inefficient process per mole UV light....

  9. Natural diatomite process for removal of radioactivity from liquid waste

    Energy Technology Data Exchange (ETDEWEB)

    Osmanlioglu, Ahmet Erdal [Radioactive Waste Management Unit (RWMU), Turkish Atomic Energy Authority, Cekmece Nuclear Research and Training Center, Altinsehir Yolu 5 km. Halkali, 34303K Cekmece, Istanbul (Turkey)]. E-mail: Erdal.Osmanlioglu@taek.gov.tr

    2007-01-15

    Diatomite has a number of unique physical properties and has found diversified industrial utilization. The filtration characteristics are particularly significant in the purification of liquids. The purpose of this study was to test natural diatomaceous earth (diatomite) as an alternative material that could be used for removal of radioactivity from liquid waste. A pilot-scale column-type device was designed. Natural diatomite samples were ground, sieved and prepared to use as sorption media. In this study, real waste liquid was used as radioactive liquid having special conditions. The liquid waste contained three radionuclides (Cs-137, Cs-134 and Co-60). Following the treatment by diatomite, the radioactivity of liquid waste was reduced from the initial 2.60 Bq/ml to less than 0.40 Bq/ml. The results of this study show that most of the radioactivity was removed from the solution by processing with diatomite.

  10. Natural diatomite process for removal of radioactivity from liquid waste

    International Nuclear Information System (INIS)

    Osmanlioglu, Ahmet Erdal

    2007-01-01

    Diatomite has a number of unique physical properties and has found diversified industrial utilization. The filtration characteristics are particularly significant in the purification of liquids. The purpose of this study was to test natural diatomaceous earth (diatomite) as an alternative material that could be used for removal of radioactivity from liquid waste. A pilot-scale column-type device was designed. Natural diatomite samples were ground, sieved and prepared to use as sorption media. In this study, real waste liquid was used as radioactive liquid having special conditions. The liquid waste contained three radionuclides (Cs-137, Cs-134 and Co-60). Following the treatment by diatomite, the radioactivity of liquid waste was reduced from the initial 2.60 Bq/ml to less than 0.40 Bq/ml. The results of this study show that most of the radioactivity was removed from the solution by processing with diatomite

  11. Natural diatomite process for removal of radioactivity from liquid waste.

    Science.gov (United States)

    Osmanlioglu, Ahmet Erdal

    2007-01-01

    Diatomite has a number of unique physical properties and has found diversified industrial utilization. The filtration characteristics are particularly significant in the purification of liquids. The purpose of this study was to test natural diatomaceous earth (diatomite) as an alternative material that could be used for removal of radioactivity from liquid waste. A pilot-scale column-type device was designed. Natural diatomite samples were ground, sieved and prepared to use as sorption media. In this study, real waste liquid was used as radioactive liquid having special conditions. The liquid waste contained three radionuclides (Cs-137, Cs-134 and Co-60). Following the treatment by diatomite, the radioactivity of liquid waste was reduced from the initial 2.60 Bq/ml to less than 0.40 Bq/ml. The results of this study show that most of the radioactivity was removed from the solution by processing with diatomite.

  12. Selective removal of chromium from sulphuric acid leach liquor of ...

    African Journals Online (AJOL)

    ... removed in multiple batch extractions from the leach liquor and titanium losses were minimal (< 1%). The chromium content of extracted solutions was reduced to less than 1 ppm and thermal hydrolysis of these solutions yielded white titanium(IV) oxide pigments that are suitable for use in the coatings pigment industry.

  13. Removal of mercury from coal via a microbial pretreatment process

    Science.gov (United States)

    Borole, Abhijeet P [Knoxville, TN; Hamilton, Choo Y [Knoxville, TN

    2011-08-16

    A process for the removal of mercury from coal prior to combustion is disclosed. The process is based on use of microorganisms to oxidize iron, sulfur and other species binding mercury within the coal, followed by volatilization of mercury by the microorganisms. The microorganisms are from a class of iron and/or sulfur oxidizing bacteria. The process involves contacting coal with the bacteria in a batch or continuous manner. The mercury is first solubilized from the coal, followed by microbial reduction to elemental mercury, which is stripped off by sparging gas and captured by a mercury recovery unit, giving mercury-free coal. The mercury can be recovered in pure form from the sorbents via additional processing.

  14. ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; Herman, D.; Pike, J.; Peters, T.

    2014-06-05

    Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

  15. Adsorptive removal of fermentation inhibitors from concentrated acid hydrolyzates of lignocellulosic biomass.

    Science.gov (United States)

    Sainio, Tuomo; Turku, Irina; Heinonen, Jari

    2011-05-01

    Adsorptive purification of concentrated acid hydrolyzate of lignocellulose was investigated. Cation exchange resin (CS16GC), neutral polymer adsorbent (XAD-16), and granulated activated carbon (GAC) were studied to remove furfural, HMF, and acetic acid from a synthetic hydrolyzate containing 20 wt.% H(2)SO(4). Adsorption isotherms were determined experimentally. Loading and regeneration were investigated in a laboratory scale column. GAC has the highest adsorption capacity, but regeneration with water was not feasible. XAD-16 and CS16GC had lower adsorption capacities but also shorter cycle times due to easier regeneration. Productivity increased when regenerating with 50 wt.% EtOH(aq) solution. To compare adsorbents, process performance was quantified by productivity and fraction of inhibitors removed. GAC yields highest performance when high purity is required and ethanol can be used in regeneration. For lower purities, XAD-16 and GAC yield approximately equal performance. When using ethanol must be avoided, CS16GC offers highest productivity. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Poly(acrylic acid) modifying bentonite with in-situ polymerization for removing lead ions.

    Science.gov (United States)

    He, Y F; Zhang, L; Yan, D Z; Liu, S L; Wang, H; Li, H R; Wang, R M

    2012-01-01

    In this paper, a new kind of poly(acrylic acid) modified clay adsorbent, the poly(acrylic acid)/bentonite composite (PAA/HB) was prepared by in-situ polymerization, and utilized to remove lead(II) ions from solutions. The maximum adsorption of adsorbent is at pH 5 for metal ions, whereas the adsorption starts at pH 2. The effects of contact time (5-60 min), initial concentration of metal ions (200-1,000 mg/L) and adsorbent dosage (0.04-0.12 g/100 mL) have been reported in this article. The experimental data were investigated by means of kinetic and equilibrium adsorption isotherms. The kinetic data were analyzed by the pseudo-first-order and pseudo-second-order equation. The experimental data fitted the pseudo-second-order kinetic model very well. Langmuir and Freundlich isotherms were tried for the system to better understand the adsorption isotherm process. The maximal adsorption capacity of the lead(II) ions on the PAA/HB, as calculated from the Langmuir model, was 769.2 mg/g. The results in this study indicated that PAA/HB was an attractive candidate for removing lead(II) (99%).

  17. Removal of ammonia solutions used in catalytic wet oxidation processes.

    Science.gov (United States)

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  18. Aluminium removal from water after defluoridation with the electrocoagulation process.

    Science.gov (United States)

    Sinha, Richa; Mathur, Sanjay; Brighu, Urmila

    2015-01-01

    Fluoride is the most electronegative element and has a strong affinity for aluminium. Owing to this fact, most of the techniques used for fluoride removal utilized aluminium compounds, which results in high concentrations of aluminium in treated water. In the present paper, a new approach is presented to meet the WHO guideline for residual aluminium concentration as 0.2 mg/L. In the present work, the electrocoagulation (EC) process was used for fluoride removal. It was found that aluminium content in water increases with an increase in the energy input. Therefore, experiments were optimized for a minimum energy input to achieve the target value (0.7 mg/L) of fluoride in resultant water. These optimized sets were used for further investigations of aluminium control. The experimental investigations revealed that use of bentonite clay as coagulant in clariflocculation brings down the aluminium concentration of water below the WHO guideline. Bentonite dose of 2 g/L was found to be the best for efficient removal of aluminium.

  19. Process for removal of sulfur compounds from fuel gases

    Science.gov (United States)

    Moore, Raymond H.; Stegen, Gary E.

    1978-01-01

    Fuel gases such as those produced in the gasification of coal are stripped of sulfur compounds and particulate matter by contact with molten metal salt. The fuel gas and salt are intimately mixed by passage through a venturi or other constriction in which the fuel gas entrains the molten salt as dispersed droplets to a gas-liquid separator. The separated molten salt is divided into a major and a minor flow portion with the minor flow portion passing on to a regenerator in which it is contacted with steam and carbon dioxide as strip gas to remove sulfur compounds. The strip gas is further processed to recover sulfur. The depleted, minor flow portion of salt is passed again into contact with the fuel gas for further sulfur removal from the gas. The sulfur depleted, fuel gas then flows through a solid absorbent for removal of salt droplets. The minor flow portion of the molten salt is then recombined with the major flow portion for feed to the venturi.

  20. Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation.

    Science.gov (United States)

    Aghazadeh, Mahdieh; Ladisch, Michael R; Engelberth, Abigail S

    2016-07-08

    Acetic acid is introduced into cellulose conversion processes as a consequence of composition of lignocellulose feedstocks, causing significant inhibition of adapted, genetically modified and wild-type S. cerevisiae in bioethanol fermentation. While adaptation or modification of yeast may reduce inhibition, the most effective approach is to remove the acetic acid prior to fermentation. This work addresses liquid-liquid extraction of acetic acid from biomass hydrolysate through a pathway that mitigates acetic acid inhibition while avoiding the negative effects of the extractant, which itself may exhibit inhibition. Candidate solvents were selected using simulation results from Aspen Plus™, based on their ability to extract acetic acid which was confirmed by experimentation. All solvents showed varying degrees of toxicity toward yeast, but the relative volatility of ethyl acetate enabled its use as simple vacuum evaporation could reduce small concentrations of aqueous ethyl acetate to minimally inhibitory levels. The toxicity threshold of ethyl acetate, in the presence of acetic acid, was found to be 10 g L(-1) . The fermentation was enhanced by extracting 90% of the acetic acid using ethyl acetate, followed by vacuum evaporation to remove 88% removal of residual ethyl acetate along with 10% of the broth. NRRL Y-1546 yeast was used to demonstrate a 13% increase in concentration, 14% in ethanol specific production rate, and 11% ethanol yield. This study demonstrated that extraction of acetic acid with ethyl acetate followed by evaporative removal of ethyl acetate from the raffinate phase has potential to significantly enhance ethanol fermentation in a corn stover bioethanol facility. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:929-937, 2016. © 2016 American Institute of Chemical Engineers.

  1. Conceptual design of a novel CO2 capture process based on precipitating amino acid solvents

    NARCIS (Netherlands)

    Sanchez Fernandez, E.; Heffernan, K.; Ham, L.V. van der; Linders, M.J.G.; Eggink, E.; Schrama, F.N.H.; Brilman, D.W.F.; Goetheer, E.L.V.; Vlugt, T.J.H.

    2013-01-01

    Amino acid salt based solvents can be used for CO2 removal from flue gas in a conventional absorption-thermal desorption process. Recently, new process concepts have been developed based on the precipitation of the amino acid zwitterion species during the absorption of CO2. In this work, a new

  2. A process to remove ammonia from PUREX plant effluents

    International Nuclear Information System (INIS)

    Moore, J.D.

    1990-01-01

    Zirconium-clad nuclear fuel from the Hanford N-Reactor is reprocessed in the PUREX (Plutonium Uranium Extraction) Plant operated by the Westinghouse Hanford Comapny. Before dissolution, cladding is chemically removed from the fuel elements with a solution of ammonium fluoride-ammonium nitrate (AFAN). a solution batch with an ammonia equivalent of about 1,100 kg is added to each fuel batch of 10 metric tons. This paper reports on this decladding process, know as the 'Zirflex' process which produces waste streams containing ammonia and ammonium slats. Waste stream treatment, includes ammonia scrubbing, scrub solution evaporation, residual solids dissolution, and chemical neutralization. These processes produce secondary liquid and gaseous waste streams containing varying concentrations of ammonia and low-level concentrations of radionuclides. Until legislative restrictions were imposed in 1987, these secondary streams were released to the soil in a liquid disposal 'crib' and to the atmosphere

  3. Treatment of highly polluted groundwater by novel iron removal process.

    Science.gov (United States)

    Sim, S J; Kang, C D; Lee, J W; Kim, W S

    2001-01-01

    The removal of ferrous iron (Fe(II)) in groundwater has been generally achieved by simple aeration, or the addition of an oxidizing agent. Aeration has been shown to be very efficient in insolubilization ferrous iron at a pH level greater than 6.5. In this study, pH was maintained over 6.5 using limestone granules under constant aeration to oxidize ferrous iron in groundwater in a limestone packed column. A sedimentation unit coupled with a membrane filtration was also developed to precipitate and filtrate the oxidized ferric compound simultaneously. Several bench-scale studies, including the effects of the limestone granule sizes, amounts and hydraulic retention time on iron removal in the limestone packed column were investigated. It was found that 550 g/L of the 7-8 mesh size limestone granules, and 20 min of hydraulic retention time in the limestone packed column, were necessary for the sufficient oxidation of 40 mg/L of iron(II) in groundwater. Long-term operation was successfully achieved in contaminated waters by removing the iron deposits on the surface of the limestone granule by continuous aeration from the bottom of the column. Periodic reverse flow helped to remove caking and fouling of membrane surface caused by the continuous filtration. Recycling of the treated water from the membrane right after reverse flow operation made possible an admissible limit of iron concentration of the treated water for drinking. The pilot-scale process was constructed and has been tested in the rural area of Korea.

  4. Extraction process for removing metallic impurities from alkalide metals

    Science.gov (United States)

    Royer, Lamar T.

    1988-01-01

    A development is described for removing metallic impurities from alkali metals by employing an extraction process wherein the metallic impurities are extracted from a molten alkali metal into molten lithium metal due to the immiscibility of the alkali metals in lithium and the miscibility of the metallic contaminants or impurities in the lithium. The purified alkali metal may be readily separated from the contaminant-containing lithium metal by simple decanting due to the differences in densities and melting temperatures of the alkali metals as compared to lithium.

  5. Precipitate hydrolysis process for the removal of organic compounds from nuclear waste slurries

    Science.gov (United States)

    Doherty, J.P.; Marek, J.C.

    1987-02-25

    A process for removing organic compounds from a nuclear waste slurry comprising reacting a mixture of radioactive waste precipitate slurry and an acid in the presence of a catalytically effective amount of a copper(II) catalyst whereby the organic compounds in the precipitate slurry are hydrolyzed to form volatile organic compounds which are separated from the reacting mixture. The resulting waste slurry, containing less than 10 percent of the original organic compounds, is subsequently blended with high level radioactive sludge land transferred to a vitrification facility for processing into borosilicate glass for long-term storage. 2 figs., 3 tabs.

  6. Kinetic Evaluation of Naphthalene Removal using Acid - Modified ...

    African Journals Online (AJOL)

    Kinetic evaluation of naphthalene onto acid – modified and unmodified bentonite clay mineral was investigated by means of the effects of concentration, contact time and pH. The amount of naphthalene adsorbed was determined spectrophotometrically. The optimum pH value and equilibrium contact time for the adsorption ...

  7. An innovative zinc oxide-coated zeolite adsorbent for removal of humic acid

    Science.gov (United States)

    Zinc oxide (ZnO)-coated zeolite adsorbents were developed by both nitric acid modification and Zn(NO3)2•6H2O functionalization of zeolite. The developed adsorbents were used for the removal of humic acid (HA) from aqueous solutions. The adsorption capacity of the adsorbents at 21...

  8. Organosilane grafted acid-activated beidellite clay for the removal of non-ionic alachlor and anionic imazaquin

    International Nuclear Information System (INIS)

    Paul, Blain; Martens, Wayde N.; Frost, Ray L.

    2011-01-01

    Clay adsorbents were prepared via two-step method to remove nonionic alachlor and anionic imazaquin herbicides from water. Firstly, layered beidellite clay, a member of smectite family, was treated with acid in hydrothermal process; secondly, common silane coupling agents, 3-chloro-propyl trimethoxysilane or triethoxy silane, were grafted on the acid treated samples to prepare adsorbent materials. The organically modified clay samples were characterized by powder X-ray diffraction, N 2 gas adsorption, and FTIR spectroscopy. It was found that the selective modification of clay samples displayed higher adsorption capacity for herbicides compared with acid activated clay. And the amount of adsorption is increased with increasing the grafting amount of silane groups. Clay grafted with 3-chloro-propyl trimethoxysilane is an excellent adsorbent for both alachlor and imazaquin but triethoxy (octyl) silane grafted clay is more efficient only for alachlor removal.

  9. Novel forward osmosis process to effectively remove heavy metal ions

    KAUST Repository

    Cui, Yue; Ge, Qingchun; Liu, Xiangyang; Chung, Neal Tai-Shung

    2014-01-01

    In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

  10. Novel forward osmosis process to effectively remove heavy metal ions

    KAUST Repository

    Cui, Yue

    2014-10-01

    In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

  11. Using Coagulation Process in Optimizing Natural Organic Matter Removal from Low Turbidity Waters

    Directory of Open Access Journals (Sweden)

    Alireza Mesdaghinia

    2006-03-01

    Full Text Available Optimization of coagulation process  for efficient removal of Natural Organic Matters (NOM has gained a lot of focus over the last years to meet the requirements of enhanced coagulation. NOM comprises both particulate and soluble components which the latter usually comprises the main portion. Removal of soluble NOM from low turbidity waters by coagulation is not a successful process unless enough attention is paid to stages of formation and development of both micro and macro-flocs. This study, which presents experimental results from pilot scale research studies aimed at optimizing coagulation process applied to synthetic raw waters supplemented by adding commercial humic acid with low turbidity levels, explains how pH and turbidity can be controlled to maximize soluble NOM removal. The removal of NOM at various coagulant doses and coagulation pHs has been assessed through raw and treated (coagulated-settled water measurements of total organic carbon (TOC. For low turbidity waters, essential floc nucleation sites can be provided by creating synthetic turbidities, for example by adding clay. Adjusting the initial pH at 5.5 or adding clay before coagulant addition allows the formation of micro-flocs as well as formation of the insoluble flocs at low coagulant doses.

  12. Investigation of tritium removal by means of organic compounds. Catalytic hydrogenation (tritiation) of linoleic acid

    International Nuclear Information System (INIS)

    El-Sharnouby, A.; Weichselgartner, H.

    1984-11-01

    In the presence of noble-metal catalysts unsaturated fatty acids such as eruic acid and linoleic acid capture hydrogen (and tritium) quantitatively. The hydrogenation reaction of eruic acid has already been reported. The experimental results of the reaction of hydrogen (and tritium) with linoleic acid are now discussed in this paper. Obviously, the use of linoleic acid shows some advantages compared with eruic acid: - the hydrogenation reaction is faster, - linoleic acid is liquid, so that the choice of additional solvents is easier, and - linoleic acid is a more or less cheap natural product, which is available from a series of seeds, so that the cost of a technical tritium removal plant is not increased by the basic chemical material. (orig.)

  13. Poorly crystalline hydroxyapatite: A novel adsorbent for enhanced fulvic acid removal from aqueous solution

    Science.gov (United States)

    Wei, Wei; Yang, Lei; Zhong, Wenhui; Cui, Jing; Wei, Zhenggui

    2015-03-01

    In this study, poorly crystalline hydroxyapatite (HAP) was developed as an efficient adsorbent for the removal of fulvic acid (FA) from aqueous solution. Surface functionality, crystallinity, and morphology of the synthetic adsorbent were studied by Fourier-transformation infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of various parameters such as crystallinity of adsorbent, contact time, adsorbent dosage, pH, initial adsorbate concentration, temperature, ionic strength and the presence of alkaline earth metal ions on FA adsorption were investigated. Results indicated that the nanosized HAP calcined at lower temperature was poorly crystalline (Xc = 0.23) and had better adsorption capacity for FA than those (Xc = 0.52, 0.86) calcined at higher temperature. FA removal was increased with increases of adsorbent dosage, temperature, ionic strength and the presence of alkali earth metal ions, but decreased as the pH increased. Kinetic studies showed that pseudo-second-order kinetic model better described the adsorption process. Equilibrium data were best described by Sips models, and the estimated maximum adsorption capacity of poorly crystalline HAP was 90.20 mg/g at 318 K, displaying higher efficiency for FA removal than previously reported adsorbents. FT-IR results revealed that FA adsorption over the adsorbent could be attributed to the surface complexation between the oxygen atom of functional groups of FA and calcium ions of HAP. Regeneration studies indicated that HAP could be recyclable for a long term. Findings of the present work highlight the potential for using poorly crystalline HAP nanoparticles as an effective and recyclable adsorbent for FA removal from aqueous solution.

  14. Autotrophic nitrogen removal process in a potable water treatment biofilter that simultaneously removes Mn and NH4(+)-N.

    Science.gov (United States)

    Cai, Yan'an; Li, Dong; Liang, Yuhai; Zeng, Huiping; Zhang, Jie

    2014-11-01

    Ammonia (NH4(+)-N) removal pathways were investigated in a potable water treatment biofilter that simultaneously removes manganese (Mn) and NH4(+)-N. The results indicated a significant loss of nitrogen in the biofilter. Both the completely autotrophic nitrogen removal over nitrite (CANON) process and nitrification were more likely to contribute to NH4(+)-N removal. Moreover, the model calculation results demonstrated that the CANON process contributed significantly to the removal of NH4(+)-N. For influent NH4(+)-N levels of 1.030 and 1.749mg/L, the CANON process contribution was about 48.5% and 46.6%, respectively. The most important finding was that anaerobic ammonia oxidation (ANAMMOX) bacteria were detectable in the biofilter. It is interesting that the CANON process was effective even for such low NH4(+)-N concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Development on the technologies for tritium removal processes

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Ki Woong; Kim, Yong Ik; Nah, Jung Won; Koo, Je Hyoo; Kim, Kwang Lak; Chung, Heung Suk; Lee, Han Soo; Cho, Yung Hyun; Paek, Seung Woo; Kang, Heui Suk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chung, Yong Won [In Hah Univ., Inchun (Korea, Republic of)

    1994-12-01

    While tritium exposure to the site-workers in Wolsung NPP is upto about 40 % of the total personnel exposure, Korea Institute of Nuclear Safety has asked tritium removal facility, as one of the requirements for post reactor construction, after operation of four CANDU reactors in Wolsung site. For the purpose of essential removal of tritium from the heavy water system of the heavy water reactors, an experiment of Ar-N{sub 2} cryogenic distillation tower was carried out as a preliminary study for development of liquid-phase catalytic exchange - cryogenic hydrogen distillation process. The steady-state reached after 50 minutes under 90 K in the Ar-N{sub 2} distillation column (inner diameter 20 mm, height 500 mm) packed with Dixon ring ({phi} 3 mm x H 3 mm), and the ratios of Ar-concentration at the top and at the bottom measured by gas chromatography within {+-}1 % relative error was approximately 93 : 3. This value was distillation performances quite higher than those estimated by computer-simulation, which might be due to good efficiency of the packing materials. Several dynamic characteristics such as height equivalent to theoretical plate or effects of the kind of packing materials for Ar-N{sub 2} distillation column to be produced will be available for design study of cryogenic hydrogen distillation process. 19 figs, 17 tabs, 21 refs. (Author).

  16. Development on the technologies for tritium removal processes

    International Nuclear Information System (INIS)

    Sung, Ki Woong; Kim, Yong Ik; Nah, Jung Won; Koo, Je Hyoo; Kim, Kwang Lak; Chung, Heung Suk; Lee, Han Soo; Cho, Yung Hyun; Paek, Seung Woo; Kang, Heui Suk; Chung, Yong Won

    1994-12-01

    While tritium exposure to the site-workers in Wolsung NPP is upto about 40 % of the total personnel exposure, Korea Institute of Nuclear Safety has asked tritium removal facility, as one of the requirements for post reactor construction, after operation of four CANDU reactors in Wolsung site. For the purpose of essential removal of tritium from the heavy water system of the heavy water reactors, an experiment of Ar-N 2 cryogenic distillation tower was carried out as a preliminary study for development of liquid-phase catalytic exchange - cryogenic hydrogen distillation process. The steady-state reached after 50 minutes under 90 K in the Ar-N 2 distillation column (inner diameter 20 mm, height 500 mm) packed with Dixon ring (φ 3 mm x H 3 mm), and the ratios of Ar-concentration at the top and at the bottom measured by gas chromatography within ±1 % relative error was approximately 93 : 3. This value was distillation performances quite higher than those estimated by computer-simulation, which might be due to good efficiency of the packing materials. Several dynamic characteristics such as height equivalent to theoretical plate or effects of the kind of packing materials for Ar-N 2 distillation column to be produced will be available for design study of cryogenic hydrogen distillation process. 19 figs, 17 tabs, 21 refs. (Author)

  17. Highly efficient removal of perfluorooctanoic acid from aqueous solution by H2O2-enhanced electrocoagulation-electroflotation technique

    Directory of Open Access Journals (Sweden)

    Bo Yang

    2016-03-01

    Full Text Available Electrocoagulation (EC technique was used to investigate the removal performance of aqueous perfluorooctanoic acid (PFOA with relatively high concentration as simulating the wastewater from organic fluorine industry. A comparison was done with the similar amount of coagulant between EC and chemical coagulation process. PFOA removal obtained was higher with EC process, especially for Fe anode. Several factors were studied to optimize the EC process. At the optimal operating parameters including 37.5 mA/cm2 of current density, initial pH 3.77, and 180 rpm of mixing speed, 93% of PFOA could be removed with 100 mg/L of initial concentration after 90-min electrolysis. Furthermore, the remove efficiency could be obviously improved by H2O2 intermittent addition, which removed more than 99% of PFOA within 40-min EC. It could be attributed to that H2O2 facilitated the oxidative transformation from ferrous to ferric ion. In addition, the adsorptive removal of aqueous PFOA on Fe flocs during EC was also verified by fourier transform infrared spectra.

  18. The AMES Laboratory chemical disposal site removal action: Source removal, processing, and disposal

    International Nuclear Information System (INIS)

    Shirley, R.S.

    1996-01-01

    The Ames Laboratory has historically supported the U.S. Department of Energy (USDOE) and its predecessor agencies by providing research into the purification and manufacturing of high purity uranium, thorium, and yttrium metals. Much of this work was accomplished in the late 1950s and early 1960s prior to the legislation of strict rules and regulations covering the disposal of radioactive and chemical wastes. As a result, approximately 800 cubic meters of low-level radioactive wastes, chemical wastes, and contaminated debris were disposed in nine near surface cells located in a 0.75 hectare plot of land owned by Iowa State University in Ames, Iowa. Under a national contract with the U.S. Army Corps of Engineers (USACE), OHM Remediation Services Corp (OHM) was tasked with providing turnkey environmental services to remove, process, package, transport, and coordinate the disposal of the waste materials and contaminated environmental media

  19. The Ames Laboratory Chemical Disposal Site removal action: Source removal, processing, and disposal

    International Nuclear Information System (INIS)

    Shirley, R.S.

    1995-01-01

    The Ames Laboratory has historically supported the US Department of Energy (USDOE) and its predecessor agencies by providing research into the purification and manufacturing of high purity uranium, thorium, and yttrium metals. Much of this work was accomplished in the late 1950s and early 1960s prior to the legislation of strict rules and regulations covering the disposal of radioactive and chemical wastes. As a result, approximately 800 cubic meters of low-level radioactive wastes, mixed wastes, and contaminated debris were disposed in nine near surface cells located in a 0.75 hectare plot of land owned by Iowa State University in Ames, Iowa. Under a national contract with the US Army Corps of Engineers (USACE), OHM Remediation Services Corp. (OHM) was tasked with providing turnkey environmental services to remove, process, package, transport, and coordinate the disposal of the waste materials and contaminated environmental media

  20. Biological removal of metal ions from aqueous process streams

    International Nuclear Information System (INIS)

    Shumate, S.E. II; Strandberg, G.W.; Parrott, J.R. Jr.

    1978-01-01

    Aqueous waste streams from nuclear fuel processing operations may contain trace quantities of heavy metals such as uranium. Conventional chemical and physical treatment may be ineffective or very expensive when uranium concentrations in the range of 10 to 100 g/m 3 must be reduced to 1 g/m 3 or less. The ability of some microorganisms to adsorb or complex dissolved heavy metals offers an alternative treatment method. Uranium uptake by Saccharomyces cerevisiae NRRL Y-2574 and a strain of Pseudomonas aeruginosa was examined to identify factors which might affect a process for the removal of uranium from wastewater streams. At uranium concentrations in the range of 10 to 500 g/m 3 , where the binding capacity of the biomass was not exceeded, temperature, pH, and initial uranium concentration were found to influence the rate of uranium uptake, but not the soluble uranium concentration at equilibrium. 6 figs

  1. Reduction of produced elementary sulfur in denitrifying sulfide removal process.

    Science.gov (United States)

    Zhou, Xu; Liu, Lihong; Chen, Chuan; Ren, Nanqi; Wang, Aijie; Lee, Duu-Jong

    2011-05-01

    Denitrifying sulfide removal (DSR) processes simultaneously convert sulfide, nitrate, and chemical oxygen demand from industrial wastewater into elemental sulfur, dinitrogen gas, and carbon dioxide, respectively. The failure of a DSR process is signaled by high concentrations of sulfide in reactor effluent. Conventionally, DSR reactor failure is blamed for overcompetition for heterotroph to autotroph communities. This study indicates that the elementary sulfur produced by oxidizing sulfide that is a recoverable resource from sulfide-laden wastewaters can be reduced back to sulfide by sulfur-reducing Methanobacterium sp. The Methanobacterium sp. was stimulated with excess organic carbon (acetate) when nitrite was completely consumed by heterotrophic denitrifiers. Adjusting hydraulic retention time of a DSR reactor when nitrite is completely consumed provides an additional control variable for maximizing DSR performance.

  2. Adsorption removal of tannic acid from aqueous solution by polyaniline: Analysis of operating parameters and mechanism.

    Science.gov (United States)

    Sun, Chencheng; Xiong, Bowen; Pan, Yang; Cui, Hao

    2017-02-01

    Polyaniline (PANI) prepared by chemical oxidation was studied for adsorption removal of tannic acid (TA) from aqueous solution. Batch adsorption studies were carried out under different adsorbent dosages, pH, ionic strength, initial TA concentration and coexisting anions. Solution pH had an important impact on TA adsorption onto PANI with optimal removal in the pH range of 8-11. TA adsorption on PANI at three ionic strength levels (0.02, 0.2 and 2molL -1 NaCl) could be well described by Langmuir model (monolayer adsorption process) and the maximum adsorption capacity was 230, 223 and 1023mgg -1 , respectively. Kinetic data showed that TA adsorption on PANI fitted well with pseudo-second-order model (controlled by chemical process). Among the coexisting anions tested, PO 4 3- significantly inhibited TA adsorption due to the enhancement of repulsive interaction. Continuous flow adsorption studies indicated good flexibility and adaptability of the PANI adsorbent under different flow rates and influent TA concentrations. The mechanism controlling TA adsorption onto PANI under different operating conditions was analyzed with the combination of electrostatic interactions, hydrogen bonding, π-π interactions and Van der Waals interactions. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Particulate removal processes and hydraulics of porous gravel media filters

    Science.gov (United States)

    Minto, J. M.; Phoenix, V. R.; Dorea, C. C.; Haynes, H.; Sloan, W. T.

    2013-12-01

    Sustainable urban Drainage Systems (SuDS) are rapidly gaining acceptance as a low-cost tool for treating urban runoff pollutants close to source. Road runoff water in particular requires treatment due to the presence of high levels of suspended particles and heavy metals adsorbed to these particles. The aim of this research is to elucidate the particle removal processes that occur within gravel filters that have so far been considered as 'black-box' systems. Based on these findings, a better understanding will be attained on what influences gravel filter removal efficiency and how this changes throughout their design life; leading to a more rational design of this useful technology. This has been achieved by tying together three disparate research elements: tracer residence time distribution curves of filters during clogging; 3D magnetic resonance imaging (MRI) of clogging filters and computational fluid dynamics (CFD) modelling of complex filter pore networks. This research relates column average changes in particle removal efficiency and tracer residence time distributions (RTDs) due to clogging with non-invasive measurement of the spatial variability in particle deposition. The CFD modelling provides a link between observed deposition patterns, flow velocities and wall shear stresses as well as the explanations for the change in RTD with clogging and the effect on particle transport. Results show that, as a filter clogs, particles take a longer, more tortuous path through the filter. This is offset by a reduction in filter volume resulting in higher flow velocities and more rapid particle transport. Higher velocities result in higher shear stresses and the development of preferential pathways in which the velocity exceeds the deposition threshold and the overall efficiency of the filter decreases. Initial pore geometry is linked to the pattern of deposition and subsequent formation of preferential pathways. These results shed light on the 'black-box' internal

  4. KINETIC MODELING AND ISOTHERM STUDIES ON A BATCH REMOVAL OF ACID RED 114 BY AN ACTIVATED PLANT BIOMASS

    Directory of Open Access Journals (Sweden)

    N. RAJAMOHAN

    2013-12-01

    Full Text Available In this paper, the dye Acid Red 114(AR 114 was removed from aqueous solutions using Acid-Activated Eichornia Crassipes (AAEC under batch conditions. The optimum conditions for AR 114 removal were found to be pH 1.5, adsorbent dosage = 1.25 g/L of solution and equilibrium time = 3 h. The equilibrium data were evaluated for compliance with Langmuir, Freundlich and Temkin isotherms and Langmuir isotherm was found to fit well. The maximum sorption capacity was estimated as 112.34 mg/g of adsorbent. Also, adsorption kinetics of the dye was studied and the rates of sorption were found to follow pseudo-second order kinetics with good correlation (R2 ≥ 0.997.The kinetic study at different temperatures revealed that the sorption was an endothermic process. The activation energy of the sorption process was estimated as 9.722 kJ/mol.

  5. Vertical eddy diffusion as a key mechanism for removing perfluorooctanoic acid (PFOA) from the global surface oceans

    International Nuclear Information System (INIS)

    Lohmann, Rainer; Jurado, Elena; Dijkstra, Henk A.; Dachs, Jordi

    2013-01-01

    Here we estimate the importance of vertical eddy diffusion in removing perfluorooctanoic acid (PFOA) from the surface Ocean and assess its importance as a global sink. Measured water column profiles of PFOA were reproduced by assuming that vertical eddy diffusion in a 3-layer ocean model is the sole cause for the transport of PFOA to depth. The global oceanic sink due to eddy diffusion for PFOA is high, with accumulated removal fluxes over the last 40 years of 660 t, with the Atlantic Ocean accounting for 70% of the global oceanic sink. The global oceans have removed 13% of all PFOA produced to a depth greater than 100 m via vertical eddy diffusion; an additional 4% has been removed via deep water formation. The top 100 m of the surface oceans store another 21% of all PFOA produced (∼1100 t). Highlights: •Eddy diffusion has removed ∼660 t of PFOA from surface oceans over the last 40 years. •Atlantic Ocean accounts for 70% of the global oceanic sink of PFOA. •Vertical eddy diffusion has moved ∼13% of PFOA to oceans deeper than 100 m. •Around 4% of PFOA has been removed via deep water formation. •The top 100 m of global oceans contain ∼21% of historical PFOA production. -- Vertical eddy diffusion is an important removal process for hydrophilic organic pollutants such as PFOA from the surface ocean

  6. Using Eggshell in Acid Orange 2 Dye Removal from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Yari

    2015-05-01

    Full Text Available Background and purpose: Generated dye wastewater by the textile industry is usually toxic, non-biodegradable and resistant in the environment. Eggshell is one of the inexpensive material and for the reason the vesicular structures can be used as a proper adsorbent for pollutants removal. The aim of this study is to investigate the efficiency of eggshell for removal of acid orange 2 dye from aqueous solution. Materials and Methods: In the experimental study was determined the efficacy of variant variables such as contact time (15, 30, 60, 90 and 120 min, pH (3, 7 and 11, adsorbent dose (10, 25, 50 and 75 g/L, and initial dye concentration (25, 50 and 100 mg/L. The concentration of dye by spectrophotometer ultraviolet/visible in the wavelength 483 nm was examined. Results: The results showed that with increasing contact time and adsorbent dose, the dye removal efficiency was increased, but with increasing pH and initial dye concentration the removal efficiency was decreased. The maximum of removal efficiency of acid orange 2 dye got in the optimum pH: 3, contact time: 90 min, adsorbent dose: 50 g/L and initial dye concentration: 25 mg/L. Adsorption of acid orange 2 dye (R2 = 0.87 follow the Freundlich isotherm. Conclusion: Eggshells can be used as an inexpensive and effective adsorbent for the removal of acid orange 2 dye.

  7. Process for winning uranium from wet process phosphoric acid

    International Nuclear Information System (INIS)

    1980-01-01

    A process is described for winning uranium from wet process phosphoric acid by means of liquid-liquid extraction with organic phosphoric acid esters. The process is optimised by keeping the sulphate percentage in the phosphoric acid below 2% by weight, and preferably below 0.6% by weight, as compared to P 2 O 5 in the phosphoric acid. This is achieved by adding an excess of Ba and/or Ca carbonate or sulfide solution and filtering off the formed calcium and/or barium sulphate precipitates. Solid KClO 3 is then added to the filtrate to oxidise U 4+ to U 6+ . The normal extraction procedure using organic phosphoric esters as extraction liquid, can then be applied. (Th.P.)

  8. Removal of uranium from spent salt from the moltensalt oxidation process

    International Nuclear Information System (INIS)

    Summers, L.; Hsu, P.C.; Holtz, E.V.; Hipple, D.; Wang, F.; Adamson, M.

    1997-03-01

    Molten salt oxidation (MSO) is a thermal process that has the capability of destroying organic constituents of mixed wastes, hazardous wastes, and energetic materials. In this process, combustible waste and air are introduced into the molten sodium carbonate salt. The organic constituents of the waste materials are oxidized to carbon dioxide and water, while most of the inorganic constituents, including toxic metals, minerals, and radioisotopes, are retained in the molten salt bath. As these impurities accumulate in the salt, the process efficiency drops and the salt must be replaced. An efficient process is needed to separate these toxic metals, minerals, and radioisotopes from the spent carbonate to avoid generating a large volume of secondary waste. Toxic metals such as cadmium, chromium, lead, and zinc etc. are removed by a method described elsewhere. This paper describes a separation strategy developed for radioisotope removal from the mixed spent salt, as well as experimental results, as part of the spent salt cleanup. As the MSO system operates, inorganic products resulting from the reaction of halides, sulfides, phosphates, metals and radionuclides with carbonate accumulate in the salt bath. These must be removed to prevent complete conversion of the sodium carbonate, which would result in eventual losses of destruction efficiency and acid scrubbing capability. There are two operational modes for salt removal: (1) during reactor operation a slip-stream of molten salt is continuously withdrawn with continuous replacement by carbonate, or (2) the spent salt melt is discharged completely and the reactor then refilled with carbonate in batch mode. Because many of the metals and/or radionuclides captured in the salt are hazardous and/or radioactive, spent salt removed from the reactor would create a large secondary waste stream without further treatment. A spent salt clean up/recovery system is necessary to segregate these materials and minimize the amount of

  9. The utilization of waste by-products for removing silicate from mineral processing wastewater via chemical precipitation.

    Science.gov (United States)

    Kang, Jianhua; Sun, Wei; Hu, Yuehua; Gao, Zhiyong; Liu, Runqing; Zhang, Qingpeng; Liu, Hang; Meng, Xiangsong

    2017-11-15

    This study investigates an environmentally friendly technology that utilizes waste by-products (waste acid and waste alkali liquids) to treat mineral processing wastewater. Chemical precipitation is used to remove silicate from scheelite (CaWO 4 ) cleaning flotation wastewater and the waste by-products are used as a substitute for calcium chloride (CaCl 2 ). A series of laboratory experiments is conducted to explain the removal of silicate and the characterization and formation mechanism of calcium silicate. The results show that silicate removal reaches 90% when the Ca:Si molar ratio exceeds 1.0. The X-ray diffraction (XRD) results confirm the characterization and formation of calcium silicate. The pH is the key factor for silicate removal, and the formation of polysilicic acid with a reduction of pH can effectively improve the silicate removal and reduce the usage of calcium. The economic analysis shows that the treatment costs with waste acid (0.63 $/m 3 ) and waste alkali (1.54 $/m 3 ) are lower than that of calcium chloride (2.38 $/m 3 ). The efficient removal of silicate is confirmed by industrial testing at a plant. The results show that silicate removal reaches 85% in the recycled water from tailings dam. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Removal of phosphorus from agricultural wastewaters using adsorption media prepared from acid mine drainage sludge

    Science.gov (United States)

    Sibrell, Philip L.; Montgomery, Gary A.; Ritenour, Kelsey L.; Tucker, Travis W.

    2009-01-01

    Excess phosphorus in wastewaters promotes eutrophication in receiving waterways. A??cost-effective method for the removal of phosphorus from water would significantly reduce the impact of such wastewaters on the environment. Acid mine drainage sludge is a waste product produced by the neutralization of acid mine drainage, and consists mainly of the same metal hydroxides used in traditional wastewater treatment for the removal of phosphorus. In this paper, we describe a method for the drying and pelletization of acid mine drainage sludge that results in a particulate media, which we have termed Ferroxysorb, for the removal of phosphorus from wastewater in an efficient packed bed contactor. Adsorption capacities are high, and kinetics rapid, such that a contact time of less than 5 min is sufficient for removal of 60-90% of the phosphorus, depending on the feed concentration and time in service. In addition, the adsorption capacity of the Ferroxysorb media was increased dramatically by using two columns in an alternating sequence so that each sludge bed receives alternating rest and adsorption cycles. A stripping procedure based on treatment with dilute sodium hydroxide was also developed that allows for recovery of the P from the media, with the possibility of generating a marketable fertilizer product. These results indicate that acid mine drainage sludges - hitherto thought of as undesirable wastes - can be used to remove phosphorus from wastewater, thus offsetting a portion of acid mine drainage treatment costs while at the same time improving water quality in sensitive watersheds.

  11. High Metal Removal Rate Process for Machining Difficult Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bates, Robert; McConnell, Elizabeth

    2016-06-29

    Machining methods across many industries generally require multiple operations to machine and process advanced materials, features with micron precision, and complex shapes. The resulting multiple machining platforms can significantly affect manufacturing cycle time and the precision of the final parts, with a resultant increase in cost and energy consumption. Ultrafast lasers represent a transformative and disruptive technology that removes material with micron precision and in a single step manufacturing process. Such precision results from athermal ablation without modification or damage to the remaining material which is the key differentiator between ultrafast laser technologies and traditional laser technologies or mechanical processes. Athermal ablation without modification or damage to the material eliminates post-processing or multiple manufacturing steps. Combined with the appropriate technology to control the motion of the work piece, ultrafast lasers are excellent candidates to provide breakthrough machining capability for difficult-to-machine materials. At the project onset in early 2012, the project team recognized that substantial effort was necessary to improve the application of ultrafast laser and precise motion control technologies (for micromachining difficult-to-machine materials) to further the aggregate throughput and yield improvements over conventional machining methods. The project described in this report advanced these leading-edge technologies thru the development and verification of two platforms: a hybrid enhanced laser chassis and a multi-application testbed.

  12. Electrode Induced Removal and Recovery of Uranium (VI) from Acidic Subsurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, Kelvin [Carnegie Mellon University

    2013-08-12

    The overarching objective of this research is to provide an improved understanding of how aqueous geochemical conditions impact the removal of U and Tc from groundwater and how engineering design may be utilized to optimize removal of these radionuclides. Experiments were designed to address the unique conditions in Area 3 of ORNL while also providing broader insight into the geochemical effectors of the removal rates and extent for U and Tc. The specific tasks of this work were to: 1) quantify the impact of common aqueous geochemical and operational conditions on the rate and extent of U removal and recovery from water, 2) investigate the removal of Tc with polarized graphite electrode, and determine the influence of geochemical and operational conditions on Tc removal and recovery, 3) determine whether U and Tc may be treated simultaneous from Area 3 groundwater, and examine the bench-scale performance of electrode-based treatment, and 4) determine the capacity of graphite electrodes for U(VI) removal and develop a mathematical, kinetic model for the removal of U(VI) from aqueous solution. Overall the body of work suggests that an electrode-based approach for the remediation of acidic subsurface environments, such as those observed in Area 3 of ORNL may be successful for the removal for both U(VI) and Tc. Carbonaceous (graphite) electrode materials are likely to be the least costly means to maximize removal rates and efficiency by maximizing the electrode surface area.

  13. Process and system for removing impurities from a gas

    Science.gov (United States)

    Henningsen, Gunnar; Knowlton, Teddy Merrill; Findlay, John George; Schlather, Jerry Neal; Turk, Brian S

    2014-04-15

    A fluidized reactor system for removing impurities from a gas and an associated process are provided. The system includes a fluidized absorber for contacting a feed gas with a sorbent stream to reduce the impurity content of the feed gas; a fluidized solids regenerator for contacting an impurity loaded sorbent stream with a regeneration gas to reduce the impurity content of the sorbent stream; a first non-mechanical gas seal forming solids transfer device adapted to receive an impurity loaded sorbent stream from the absorber and transport the impurity loaded sorbent stream to the regenerator at a controllable flow rate in response to an aeration gas; and a second non-mechanical gas seal forming solids transfer device adapted to receive a sorbent stream of reduced impurity content from the regenerator and transfer the sorbent stream of reduced impurity content to the absorber without changing the flow rate of the sorbent stream.

  14. Crude oil polycyclic aromatic hydrocarbons removal via clay-microbe-oil interactions: Effect of acid activated clay minerals.

    Science.gov (United States)

    Ugochukwu, Uzochukwu C; Fialips, Claire I

    2017-07-01

    Acid treatment of clay minerals is known to modify their properties such as increase their surface area and surface acidity, making them suitable as catalysts in many chemical processes. However, the role of these surface properties during biodegradation processes of polycyclic aromatic hydrocarbons (PAHs) is only known for mild acid (0.5 M Hydrochloric acid) treated clays. Four different clay minerals were used for this study: a montmorillonite, a saponite, a palygorskite and a kaolinite. They were treated with 3 M hydrochloric acid to produce acid activated clay minerals. The role of the acid activated montmorillonite, saponite, palygorskite and kaolinite in comparison with the unmodified clay minerals in the removal of PAHs during biodegradation was investigated in microcosm experiments. The microcosm experiments contained micro-organisms, oil, and clays in aqueous medium with a hydrocarbon degrading microorganism community predominantly composed of Alcanivorax spp. Obtained results indicated that acid activated clays and unmodified kaolinite did not enhance the biodegradation of the PAHs whereas unmodified montmorillonite, palygorskite and saponite enhanced their biodegradation. In addition, unmodified palygorskite adsorbed the PAHs significantly due to its unique channel structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Removal of heavy metals from contaminated soil by electrodialytic remediation enhanced with organic acids.

    Science.gov (United States)

    Merdoud, Ouarda; Cameselle, Claudio; Boulakradeche, Mohamed Oualid; Akretche, Djamal Eddine

    2016-11-09

    The soil from an industrial area in Algeria was contaminated with Cr (8370 mg kg -1 ), Ni (1135 mg kg -1 ) and zinc (1200 mg kg -1 ). The electrodialytic remediation of this soil was studied using citric acid and EDTA as facilitating agents. 0.1 M citric acid or EDTA was added directly to the soil before it was introduced in an electrodialytic cell in an attempt to enhance the heavy metal solubility in the interstitial fluid. The more acidic pH in the soil when citric acid was used as the facilitating agent was not enough to mobilize and remove the metals from the soil. Only 7.2% of Ni and 6.7% of Zn were removed from the soil in the test with citric acid. The best results were found with EDTA, which was able to solubilize and complex Zn and Ni forming negatively charged complexes that were transported and accumulated in the anolyte. Complete removal was observed for Ni and Zn in the electrodialytic treatment with EDTA. Minor amounts of Cr were removed with both EDTA and citric acid.

  16. Effects on physicochemical characteristics of yoghurt and ice cream with fatty acid modification and cholesterol removal

    International Nuclear Information System (INIS)

    Nadeem, M.; Ullah, R.; Arif, A.M.

    2015-01-01

    This study investigated the effect of fatty acid modification and cholesterol removal on physico-chemical characteristics of yoghurt and ice cream. Fatty acid profile of milk fat was modified by feeding calcium salts of soybean oil fatty acids to cows and cholesterol was removed by b-cyclodextrin b-cyclodextrin removed 76% and 60% cholesterol from yoghurt and ice cream. Modification of fatty acid composition did not have a significant effect on a-tocopherol content; while b-cyclodextrin treated milk had substantially lower a-tocopherol content. The concentration of a-tocopherol in control and b-cyclodextrin treated yoghurt was 45.62, 32.73 mg/g and 210.34, 185.56 mg/g for ice cream, respectively. Fatty acid modification and cholesterol removal significantly decreased the overrun in ice cream (P<0.05), with no effect on sensory characteristics of yoghurt and ice cream. These results evidenced that milk with higher content of unsaturated fatty acids and low cholesterol can be used in the formulation of yoghurt and ice cream with improved health benefits and suitable sensory features. (author)

  17. Veratric acid removal from water by electrochemical oxidation on BDD anode

    Science.gov (United States)

    Jum'h, Inshad; Abdelhay, Arwa; Telfah, Ahmad; Al-Akhras, M.-Ali; Al-Kazwini, Akeel; Rosiwal, Stefan

    2018-02-01

    The efficiency of boron doped diamond (BDD) in the electrochemical treatment of synthetically contaminated water with veratric acid (VA), one kind of polyphenolic type compounds, is investigated in this work. A BDD electrode was practically fabricated using hot filament chemical vapor deposition (HFCVD). Later on, the BDD electrode was implemented as an anode in a batch electrolytic reactor. The effect of operating factors such as the initial concentration of VA, NaCl addition, and supporting electrolyte type (H2SO4, H3PO4 and Na2SO4) was studied. The chemical oxygen demand (COD) measurements were conducted to study the VA electrolysis kinetics. The experimental data suggested that sodium sulfate was the best supporting electrolyte as the COD removal reached a percentage of 100% using 1 mmol/dm3 as VA concentration. The kinetics of the COD decay of the VA electrolysis were found to obey the pseudo-first order model. Remarkably, the electrolysis process is significantly speeded up once chloride is added to the reaction. The complete COD removal was achieved in 60 minutes of treatment.

  18. Removal of radium-226 from radium-contaminated soil using humic acid by column leaching method

    International Nuclear Information System (INIS)

    Esther Phillip; Muhamad Samudi Yasir

    2012-01-01

    In this study, evaluation of radium-226 removal from radium-contaminated soil using humic acid extracted from peat soil by column leaching method was carried out. Humic acid of concentration 100 ppm and pH 7 was leached through a column packed with radium-contaminated soil and leachates collected were analysed with gamma spectrometer to determine the leached radium-226. Results obtained indicated low removal of radium-226 between 1 - 4 %. Meanwhile, leaching profile revealed that radium-226 was bound to soil components with three different strength, thus resulting in three phases of radium-226 removal. It was estimated that the total removal of radium-226 from 10 g radium-contaminated soil sample studied could be achieved using approximately 31500 - 31850 ml HA solutions with leaching rate of 1 ml/ min. (author)

  19. Biological removal of iron and manganese in rapid sand filters - Process understanding of iron and manganese removal

    DEFF Research Database (Denmark)

    Lin, Katie

    to precipitation and corrosion. Manganese and iron can either be removed physico-chemically or biologically or combined. The physico-chemical oxidation and precipitation of manganese can theoretically be achieved by aeration, but this process is slow unless pH is raised far above neutral, making the removal...... of manganese by simple aeration and precipitation under normal drinking water treatment conditions insignificant. Manganese may also be oxidized autocatalytically. Iron is usually easier to remove. First, iron is rapidly chemically oxidized by oxygen at neutral pH followed by precipitation and filtration......-filter, where iron is removed. Step 2: Filtration in an after-filter where e.g. ammonium and manganese is removed. The treatment relies on microbial processes and may present an alternative, greener and more sustainable approach for drinking water production spending less chemicals and energy than chemical (e...

  20. Radium removal processes capital and operating cost estimates

    International Nuclear Information System (INIS)

    Kelly, F.J.

    1979-09-01

    An estimate of the fixed capital and operating costs for two alternative processes for the removal of dissolved Ra-226 from uranium mill effluent in Elliot Lake, Ontario is presented. Process 1 consists of barium-radium coprecipitation followed by coagulation, flocculation and sedimentation. Process 2 consists of barium-radium coprecipitation followed by gravity media filtration, sand filter backwashing and sedimentation. Cost estimates were prepared for 18 different plant configurations designed to treat 1000 and 4000 imperial gallons per minute (ig/m) of effluent, 24 hrs per day, 7 days per week and 365 days per year with several equipment options. The estimated fixed capital costs for plants equipped with gravity filters were less than those equipped with circular clarifiers. The capital costs ranged from $552,000 with a flow rate of 1000 ig/m to $2,578,000 with a flow rate of 4000 ig/m. Estimated annual operating costs, based on a plant life of 10 years, ranged from $298,000 with a flow rate of 1000 ig/m to $1,061,000 with a flow rate of 4000 ig/m

  1. Acid in perchloroethylene scrubber solutions used in HTGR fuel preparation processes. Analytical chemistry studies

    International Nuclear Information System (INIS)

    Lee, D.A.

    1979-02-01

    Acids and corrosion products in used perchloroethylene scrubber solutions collected from HTGR fuel preparation processes have been analyzed by several analytical methods to determine the source and possible remedy of the corrosion caused by these solutions. Hydrochloric acid was found to be concentrated on the carbon particles suspended in perchloroethylene. Filtration of carbon from the scrubber solutions removed the acid corrosion source in the process equipment. Corrosion products chemisorbed on the carbon particles were identified. Filtered perchloroethylene from used scrubber solutions contained practically no acid. It is recommended that carbon particles be separated from the scrubber solutions immediately after the scrubbing process to remove the source of acid and that an inhibitor be used to prevent the hydrolysis of perchloroethylene and the formation of acids

  2. Poorly crystalline hydroxyapatite: A novel adsorbent for enhanced fulvic acid removal from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Wei [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023 (China); Yang, Lei; Zhong, Wenhui; Cui, Jing [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Wei, Zhenggui, E-mail: weizhenggui@gmail.com [Department of Environmental Science and Engineering, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023 (China); Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023 (China)

    2015-03-30

    Graphical abstract: - Highlights: • Poorly crystalline HAP was firstly used for FA removal from aqueous solution. • The maximum adsorption capacity was determined to be 90.20 mg/g at 318 K. • Adsorption kinetics, isotherms and thermodynamic have been studied in detail. • Adsorption mechanism involved surface complexation, electrostatic interaction and hydrogen bonding. - Abstract: In this study, poorly crystalline hydroxyapatite (HAP) was developed as an efficient adsorbent for the removal of fulvic acid (FA) from aqueous solution. Surface functionality, crystallinity, and morphology of the synthetic adsorbent were studied by Fourier-transformation infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of various parameters such as crystallinity of adsorbent, contact time, adsorbent dosage, pH, initial adsorbate concentration, temperature, ionic strength and the presence of alkaline earth metal ions on FA adsorption were investigated. Results indicated that the nanosized HAP calcined at lower temperature was poorly crystalline (X{sub c} = 0.23) and had better adsorption capacity for FA than those (X{sub c} = 0.52, 0.86) calcined at higher temperature. FA removal was increased with increases of adsorbent dosage, temperature, ionic strength and the presence of alkali earth metal ions, but decreased as the pH increased. Kinetic studies showed that pseudo-second-order kinetic model better described the adsorption process. Equilibrium data were best described by Sips models, and the estimated maximum adsorption capacity of poorly crystalline HAP was 90.20 mg/g at 318 K, displaying higher efficiency for FA removal than previously reported adsorbents. FT-IR results revealed that FA adsorption over the adsorbent could be attributed to the surface complexation between the oxygen atom of functional groups of FA and calcium ions of HAP. Regeneration studies indicated that HAP could be recyclable for a long

  3. Iron removal from acid mine drainage by wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Sexstone, A.J.; Skousen, J.G.; Calabrese, J.; Bhumbla, D.K.; Cliff, J.; Sencindiver, J.C.; Bissonnette, G.K.

    1999-07-01

    Neutralization of acid mine drainage (AMD) in man-made cattail (Typha) wetlands was investigated over a four-year period utilizing experimental models constructed in a greenhouse. A naturally occurring AMD (430 mg/L Fe, 5 mg/L Mn, 2,900 mg/L sulfate, pH 2.75) was collected in the field and added to the greenhouse wetlands at 60.5 L/day. Monthly water samples from four depths (10, 20, 30, and 40 cm) were obtained from the influent, midpoint, and effluent locations of the wetland. During the first year of AMD treatment, near neutral pH (6.5) and anoxic conditions ({minus}300 mV) were observed in subsurface sediments of wetlands. The wetlands retained an estimated 65% of the total applied iron in the first year, primarily in the exchangeable, organically bound, and oxide form. During later years, 20 to 30% of the influent iron was retained predominantly as precipitated oxides. Iron sulfides resulting form sulfate reduction accounted for less than 5% of the iron retained, and were recovered primarily as monosulfides during the first year and as disulfides in the fourth year. Improvement in effluent pH was primarily attributed to limestone dissolution in the anaerobic subsurface sediments, which decreased with time. Constructed wetlands exhibit finite lives for effective AMD treatment and provisions should be made for their periodic rejuvenation or replacement.

  4. A new chemical system solution for acid gas removal

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, M.; Rolker, J.; Witthaut, D.; Schulze, S. [Evonik Industries AG, Hanau (Germany); Buchholz, S. [Evonik Industries AG, Marl (Germany)

    2012-07-01

    An energy-efficient absorbent formulation fors eparating acid gases (e.g. CO{sub 2}, H2S) from gas streams such as natural gas, syngas or flue gas is important for a number of industrial applications. In many cases, a substantial share of their costs is driven by the operational expenditure (OPEX) of the CO{sub 2} separation unit. One possible strategy for reducing OPEX is the improvement of the absorbent performance. Although a number of absorbents for the separation of CO{sub 2} from gas streams exist, there is still a need to develop CO{sub 2} absorbents with an improved absorption performance, less corrosion and foaming, no nitrosamine formation, lower energy requirement and therefore less OPEX. This contribution aims at giving a brief state-of-the-art overview followed by an introduction and performance characterization of a new family of amine-based CO{sub 2} absorbents. High cyclic capacities in the range of 2.9 to 3.2 mol CO{sub 2} kg{sup -1} absorbent and low absorption enthalpies of about -30 kJ mol{sup -1} allow for significant savings in the regeneration energy of the new absorbent system. Calculations with the modified Kremser model indicate a reduction in the specific reboiler heat duty of 45 %. Moreover, the high-performance absorbents developed show much lower corrosion rates than state-of-the-art solutions that are currently employed. (orig.)

  5. Process of recovering uranium from wet process acid

    International Nuclear Information System (INIS)

    York, W.R.

    1983-01-01

    Entrainment of contaminated water in the organic phase and poor phase disengagement is prevented in the second cycle scrubber, in a two cycle uranium recovery process, by washing the organic solvent stream containing entrained H 3 PO 4 from the second cycle extractor, with a dilute aqueous sulfuric or nitric acid solution in an acid scrubber, prior to passing the solvent stream into the second cycle stripper. (author)

  6. Hydrotalcite formation facilitates effective contaminant and radionuclide removal from acidic uranium mine barren lixiviant

    International Nuclear Information System (INIS)

    Douglas, Grant; Shackleton, Mark; Woods, Peter

    2014-01-01

    Highlights: • Remediation of barren lixiviant using hydrotalcite precipitation. • High U and rare earth element concentration factor. • Hydrotalcite may be further modified for long-term disposal. • Potential application to U and other commodities. - Abstract: An assessment of hydrotalcite (HT) formation as a method to neutralise acidity and remove trace elements was undertaken using barren lixiviant from Heathgate Resources’ Beverley North in situ recovery (ISR) U mine in South Australia. This study demonstrated proof of concept in terms of the neutralisation of acidity and concomitant removal of a range of trace elements and U–Th series radionuclides from the barren lixiviant using MgCl 2 as a supplementary Mg source to optimise Mg:Al mol ratios and NaOH as the neutralising agent. Hydrotalcite was the predominant mineral formed during neutralisation, hosting a range of elements including substantial U (∼0.2%) and rare earth elements (REE ∼0.1%). High U and REE recovery (∼99%) from barren lixiviant after HT precipitation indicates a potential to both remediate barren lixiviant and to offset remediation costs. Alternatively, HT precipitates formed during barren lixiviant neutralisation may be further stabilised via calcination, silicification or a combination thereof forming minerals potentially amenable for inclusion in a long-term waste repository at the cessation of ISR mining. Importantly, the composition of the neutralised barren lixiviant produced via HT precipitation is similar to that of existing groundwater allowing for the possibility of direct aquifer re-injection after remediation. A potential exists to apply this HT-based remediation technology to conventional or ISR U mines (or mines exploiting other commodities) and allows for the prospect of a fully integrated ISR mining, processing and lixiviant remediation strategy consistent with stringent environmental and mine closure standards

  7. Adsorption and removal of clofibric acid and diclofenac from water with MIEX resin.

    Science.gov (United States)

    Lu, Xian; Shao, Yisheng; Gao, Naiyun; Chen, Juxiang; Zhang, Yansen; Wang, Qiongfang; Lu, Yuqi

    2016-10-01

    This study demonstrates the use of MIEX resin as an efficient adsorbent for the removal of clofibric acid (CA) and diclofenac (DCF). The adsorption performance of CA and DCF are investigated by a batch mode in single-component or bi-component adsorption system. Various factors influencing the adsorption of CA and DCF, including initial concentration, contact time, adsorbent dosage, initial solution pH, agitation speed, natural organic matter and coexistent anions are studied. The Langmuir model can well describe CA adsorption in single-component system, while the Freundlich model gives better fitting in bi-component system. The DCF adsorption can be well fitted by the Freundlich model in both systems. Thermodynamic analyses show that the adsorption of CA and DCF is an endothermic (ΔH(o) > 0), entropy driven (ΔS(o) > 0) process and more randomness exists in the DCF adsorption process. The values of Gibbs free energy (ΔG(o)  0) for CA adsorption. The kinetic data suggest the adsorption of CA and DCF follow the pseudo-first-order model in both systems and the intra-particle is not the unique rate-limiting step. The adsorption process is controlled simultaneously by external mass transfer and surface diffusion according to the surface diffusion modified Biot number (Bis) ranging from 1.06 to 26.15. Moreover, the possible removal mechanism for CA and DCF is respectively proposed based on the ion exchange stoichiometry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Removable partial denture alloys processed by laser-sintering technique.

    Science.gov (United States)

    Alageel, Omar; Abdallah, Mohamed-Nur; Alsheghri, Ammar; Song, Jun; Caron, Eric; Tamimi, Faleh

    2018-04-01

    Removable partial dentures (RPDs) are traditionally made using a casting technique. New additive manufacturing processes based on laser sintering has been developed for quick fabrication of RPDs metal frameworks at low cost. The objective of this study was to characterize the mechanical, physical, and biocompatibility properties of RPD cobalt-chromium (Co-Cr) alloys produced by two laser-sintering systems and compare them to those prepared using traditional casting methods. The laser-sintered Co-Cr alloys were processed by the selective laser-sintering method (SLS) and the direct metal laser-sintering (DMLS) method using the Phenix system (L-1) and EOS system (L-2), respectively. L-1 and L-2 techniques were 8 and 3.5 times more precise than the casting (CC) technique (p laser-sintered and cast alloys were biocompatible. In conclusion, laser-sintered alloys are more precise and present better mechanical and fatigue properties than cast alloys for RPDs. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1174-1185, 2018. © 2017 Wiley Periodicals, Inc.

  9. Double liquid membrane system for the removal of actinides and lanthanides from acidic nuclear wastes

    International Nuclear Information System (INIS)

    Chiarizia, R.; Danesi, P.R.

    1985-01-01

    Supported liquid membranes (SLM), consisting of an organic solution of n-octyl-(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and tributyl-phosphate (TBP) in decalin are able to perform selective separation and concentration of actinide and lanthanide ions from aqueous nitrate feed solutions and synthetic nuclear wastes. In the membrane process a possible strip solution is a mixture of formic acid and hydroxylammonium formate (HAF). The effectiveness of this strip solution is reduced and eventually nullified by the simultaneous transfer through the SLM of nitric acid which accumulates in the strip solution. A possible way to overcome this drawback is to make use of a second SLM consisting of a primary amine which is able to extract only HNO 3 from the strip solution. In this work the results obtained by experimentally studying the membrane system: synthetic nuclear waste/CMPO-TBP membrane/HCOOH-HAF strip solution/primary amine membrane/NaOH solution, are reported. They show that the use of a second liquid membrane is effective in controlling the HNO 3 concentration in the strip solution, thus allowing the actinide and lanthanide ions removal from the feed solution to proceed to completion. 15 refs., 10 figs., 1 tab

  10. Selective removal of phosphate for analysis of organic acids in complex samples.

    Science.gov (United States)

    Deshmukh, Sandeep; Frolov, Andrej; Marcillo, Andrea; Birkemeyer, Claudia

    2015-04-03

    Accurate quantitation of compounds in samples of biological origin is often hampered by matrix interferences one of which occurs in GC-MS analysis from the presence of highly abundant phosphate. Consequently, high concentrations of phosphate need to be removed before sample analysis. Within this context, we screened 17 anion exchange solid-phase extraction (SPE) materials for selective phosphate removal using different protocols to meet the challenge of simultaneous recovery of six common organic acids in aqueous samples prior to derivatization for GC-MS analysis. Up to 75% recovery was achieved for the most organic acids, only the low pKa tartaric and citric acids were badly recovered. Compared to the traditional approach of phosphate removal by precipitation, SPE had a broader compatibility with common detection methods and performed more selectively among the organic acids under investigation. Based on the results of this study, it is recommended that phosphate removal strategies during the analysis of biologically relevant small molecular weight organic acids consider the respective pKa of the anticipated analytes and the detection method of choice. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Efficient removal of malachite green dye using biodegradable graft copolymer derived from amylopectin and poly(acrylic acid).

    Science.gov (United States)

    Sarkar, Amit Kumar; Pal, Aniruddha; Ghorai, Soumitra; Mandre, N R; Pal, Sagar

    2014-10-13

    This article reports on the application of a high performance biodegradable adsorbent based on amylopectin and poly(acrylic acid) (AP-g-PAA) for removal of toxic malachite green dye (MG) from aqueous solution. The graft copolymer has been synthesized and characterized using various techniques including FTIR, GPC, SEM and XRD analyses. Biodegradation study suggests that the co-polymer is biodegradable in nature. The adsorbent shows excellent potential (Qmax, 352.11 mg g(-1); 99.05% of MG has been removed within 30 min) for removal of MG from aqueous solution. It has been observed that point to zero charge (pzc) of graft copolymer plays significant role in adsorption efficacy. The adsorption kinetics and isotherm follow pseudo-second order and Langmuir isotherm models, respectively. Thermodynamics parameters suggest that the process of dye uptake is spontaneous. Finally desorption study shows excellent regeneration efficiency of adsorbent. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Studies on removal of plutonium from oxalic acid containing hydrochloric acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ghadse, D R; Noronha, D M; Joshi, A R [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Solution containing hydrochloric acid, oxalic acid and considerable quantities of plutonium may be generated while recycling of scrap produced during the metallic fuel fabrication. Plutonium from such waste is normally recovered by anion exchange method after the destruction of oxalic acid using suitable oxidising agent. Solvent extraction and ion exchange methods are being explored in this laboratory for recovery of Pu from oxalic acid containing HCl solutions without prior destruction of oxalic acid. This paper describes the results on the determination of distribution ratios for extraction of Pu(IV) from hydrochloric acid using Aliquot-336 or HDEHP under varying experimental conditions. (author). 5 refs., 5 tabs.

  13. Effectiveness of Hand Sanitizers with and without Organic Acids for Removal of Rhinovirus from Hands ▿

    Science.gov (United States)

    Turner, Ronald B.; Fuls, Janice L.; Rodgers, Nancy D.

    2010-01-01

    These studies evaluated the effectiveness of ethanol hand sanitizers with or without organic acids to remove detectable rhinovirus from the hands and prevent experimental rhinovirus infection. Ethanol hand sanitizers were significantly more effective than hand washing with soap and water. The addition of organic acids to the ethanol provided residual virucidal activity that persisted for at least 4 h. Whether these treatments will reduce rhinovirus infection in the natural setting remains to be determined. PMID:20047916

  14. Process for the preparation of lactic acid and glyceric acid

    Science.gov (United States)

    Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

    2008-12-02

    Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

  15. Pervious concrete reactive barrier for removal of heavy metals from acid mine drainage − column study

    Energy Technology Data Exchange (ETDEWEB)

    Shabalala, Ayanda N., E-mail: Ayanda.Shabalala@ump.ac.za [University of Johannesburg, PO Box 524, Auckland Park 2006 (South Africa); Ekolu, Stephen O. [University of Johannesburg, PO Box 524, Auckland Park 2006 (South Africa); Diop, Souleymane [Council for Geoscience, Private bag x112, Pretoria, 0001 (South Africa); Solomon, Fitsum [University of Johannesburg, PO Box 524, Auckland Park 2006 (South Africa)

    2017-02-05

    Highlights: • Pervious concrete raises the low pH of acid mine drainage up to 12; heavy metals precipitate. • Pervious concrete successfully removed greater than 99% of inorganic contaminants. • Ca(OH){sub 2} in pervious concrete reacts with SO{sub 4}{sup 2−} in acid mine drainage to form expansive gypsum. • Incorporating fly ash into pervious concrete mitigates damage caused by gypsum. • Pervious concrete reactive barrier offers a promising alternative method for treatment of acid mine drainage. - Abstract: This paper presents a column study conducted to investigate the potential use of pervious concrete as a reactive barrier for treatment of water impacted by mine waste. The study was done using acid mine drainage (AMD) collected from a gold mine (WZ) and a coalfield (TDB). Pervious concrete mixtures consisting of Portland cement CEM I 52.5R with or without 30% fly ash (FA) were prepared at a water-cementitious ratio of 0.27 then used to make cubes which were employed in the reactor columns. It was found that the removal efficiency levels of Al, Fe, Mn, Co and Ni were 75%, 98%, 99%, 94% and 95% for WZ; 87%, 96%, 99%, 98% and 90% for TDB, respectively. The high rate of acid reduction and metal removal by pervious concrete is attributed to dissolution of portlandite which is a typical constituent of concrete. The dominant reaction product in all four columns was gypsum, which also contributed to some removal of sulphate from AMD. Formation of gypsum, goethite, and Glauber’s salt were identified. Precipitation of metal hydroxides seems to be the dominant metal removal mechanism. Use of pervious concrete offers a promising alternative treatment method for polluted or acidic mine water.

  16. Pervious concrete reactive barrier for removal of heavy metals from acid mine drainage − column study

    International Nuclear Information System (INIS)

    Shabalala, Ayanda N.; Ekolu, Stephen O.; Diop, Souleymane; Solomon, Fitsum

    2017-01-01

    Highlights: • Pervious concrete raises the low pH of acid mine drainage up to 12; heavy metals precipitate. • Pervious concrete successfully removed greater than 99% of inorganic contaminants. • Ca(OH)_2 in pervious concrete reacts with SO_4"2"− in acid mine drainage to form expansive gypsum. • Incorporating fly ash into pervious concrete mitigates damage caused by gypsum. • Pervious concrete reactive barrier offers a promising alternative method for treatment of acid mine drainage. - Abstract: This paper presents a column study conducted to investigate the potential use of pervious concrete as a reactive barrier for treatment of water impacted by mine waste. The study was done using acid mine drainage (AMD) collected from a gold mine (WZ) and a coalfield (TDB). Pervious concrete mixtures consisting of Portland cement CEM I 52.5R with or without 30% fly ash (FA) were prepared at a water-cementitious ratio of 0.27 then used to make cubes which were employed in the reactor columns. It was found that the removal efficiency levels of Al, Fe, Mn, Co and Ni were 75%, 98%, 99%, 94% and 95% for WZ; 87%, 96%, 99%, 98% and 90% for TDB, respectively. The high rate of acid reduction and metal removal by pervious concrete is attributed to dissolution of portlandite which is a typical constituent of concrete. The dominant reaction product in all four columns was gypsum, which also contributed to some removal of sulphate from AMD. Formation of gypsum, goethite, and Glauber’s salt were identified. Precipitation of metal hydroxides seems to be the dominant metal removal mechanism. Use of pervious concrete offers a promising alternative treatment method for polluted or acidic mine water.

  17. British strong-acid leach process targeted at refractory uranium ores

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    The UKAEA-patented strong-acid leach process for refractory U ores is briefly outlined with emphasis on its variations from the conventional dilute-acid process and the projected economics for a processing plant using this process. The process uses 6N H 2 SO 4 with a sharply reduced leaching time over conventional processes. The solubilized U is removed by percolation and the use of only about 10 percent liquid produces less effluent. Conventional processing plant equipment can be used except at the feed preparation, acid mixing, curing, and washing stages. Ore can be processed at larger grain sizes and the milling is done in a dry rod mill. Alternatives to the percolation removal of U are listed. Other work being done by UKAEA on U recovery from ores is briefly indicated. (U.S.)

  18. A-Cell equipment removal quality process plan

    International Nuclear Information System (INIS)

    TAKASUMI, D.S.

    1999-01-01

    This document establishes the quality assuring activities used to manage the 324 building A-Cell equipment removal activity. This activity will package, remove, transport and dispose of the equipment in A-Cell. This document is provided to ensure that appropriate and effective quality assuring activities have been incorporated into the work controlling documentation and procedures

  19. Removal of Cu(Ⅱ) from acidic electroplating effluent by biochars generated from crop straws

    Institute of Scientific and Technical Information of China (English)

    Xuejiao Tong; Renkou Xu

    2013-01-01

    The removal efficiency of copper (Cu(Ⅱ)) from an actual acidic electroplating effluent by biochars generated from canola,rice,soybean and peanut straws was investigated.The biochars simultaneously removed Cu(Ⅱ) from the effluent,mainly through the mechanisms of adsorption and precipitation,and neutralized its acidity.The removal efficiency of Cu(Ⅱ) by the biochars followed the order:peanut straw char > soybean straw char > canola straw char > rice straw char >> a commercial activated carbonaceous material,which is consistent with the alkalinity of the biochars.The pH of the effluent was a key factor determining the removal efficiency of Cu(Ⅱ)by biochars.Raising the initial pH of the effluent enhanced the removal of Cu(Ⅱ) from it.The optimum pyrolysis temperature was 400℃ for producing biochar from crop straws for acidic wastewater treatment,and the optimum reaction time was 8 hr.

  20. Survey and Down-Selection of Acid Gas Removal Systems for the Thermochemical Conversion of Biomass to Ethanol with a Detailed Analysis of an MDEA System

    Energy Technology Data Exchange (ETDEWEB)

    Nexant, Inc., San Francisco, California

    2011-05-01

    The first section (Task 1) of this report by Nexant includes a survey and screening of various acid gas removal processes in order to evaluate their capability to meet the specific design requirements for thermochemical ethanol synthesis in NREL's thermochemical ethanol design report (Phillips et al. 2007, NREL/TP-510-41168). MDEA and selexol were short-listed as the most promising acid-gas removal agents based on work described in Task 1. The second report section (Task 2) describes a detailed design of an MDEA (methyl diethanol amine) based acid gas removal system for removing CO2 and H2S from biomass-derived syngas. Only MDEA was chosen for detailed study because of the available resources.

  1. 512-S Facility, Actinide Removal Process Radiological Design Summary Report

    International Nuclear Information System (INIS)

    Nathan, S.J.

    2004-01-01

    This report contains top-level requirements for the various areas of radiological protection for workers. Detailed quotations of the requirements for applicable regulatory documents can be found in the Radiological Design Summary Report Implementation Guide. For the purposes of demonstrating compliance with these requirements, per Engineering Standard 01064, ''shall consider / shall evaluate'' indicates that the designer must examine the requirement for the design and either incorporate or provide a technical justification as to why the requirement is not incorporated. This report describes how the Building 512-S, Actinide Removal Process meets the required radiological design criteria and requirements based on 10CFR835, DOE Order 420.1A, WSRC Manual 5Q and various other DOE guides and handbooks. The analyses supporting this Radiological Design Summary Report initially used a source term of 10.6 Ci/gallon of Cs-137 as the basis for bulk shielding calculations. As the project evolved, the source term was reduced to 1.1 Ci/gallon of Cs-137. This latter source term forms the basis for later dose rate evaluations

  2. Simultaneous Removal of Lindane, Lead and Cadmium from Soils by Rhamnolipids Combined with Citric Acid

    Science.gov (United States)

    Long, Tao; Ying, Rongrong; Ye, Mao; Zhang, Shengtian; Li, Qun; Zhou, Yan; Lin, Yusuo

    2015-01-01

    This study investigated the performance of rhamnolipids-citric acid mixed agents in simultaneous desorption of lindane and heavy metals from soils. The capacity of the mixed agents to solubilize lindane, lead and cadmium in aqueous solution was also explored. The results showed that the presence of citric acid greatly enhanced the solubilization of lindane and cadmium by rhamnolipids. A combined effect of the mixed agents on lindane and heavy metals removal from soils was observed. The maximum desorption ratios for lindane, cadmium and lead were 85.4%, 76.4% and 28.1%, respectively, for the mixed agents containing 1% rhamnolipidsand 0.1 mol/L citric acid. The results also suggest that the removal efficiencies of lead and cadmium were strongly related to their speciations in soils, and metals in the exchangeable and carbonate forms were easier to be removed. Our study suggests that the combining use of rhamnolipids and citric acid is a promising alternative to simultaneously remove organochlorine pesticides and heavy metals from soils. PMID:26087302

  3. Removal of pharmaceuticals in biologically treated wastewater by chlorine dioxide or peracetic acid

    DEFF Research Database (Denmark)

    Hey, G.; Ledin, Anna; La Cour Jansen, Jes

    2012-01-01

    l and clofibric acid, a metabol i te of clofibrate) were used as target substances at 40 (g/L ini tial concentration. Three di fferent wastewaters types originating from two WWTPs were used. One wastewater was col lected after extended ni trogen removal in activated sludge, one after treatment wi th...

  4. Removal of actinides from dissolved ORNL MVST sludge using the TRUEX process

    International Nuclear Information System (INIS)

    Spencer, B.B.; Egan, B.Z.; Chase, C.W.

    1997-07-01

    Experiments were conducted to evaluate the transuranium extraction process for partitioning actinides from actual dissolved high-level radioactive waste sludge. All tests were performed at ambient temperature. Time and budget constraints permitted only two experimental campaigns. Samples of sludge from Melton Valley Storage Tank W-25 were rinsed with mild caustic (0.2 M NaOH) to reduce the concentrations of nitrates and fission products associated with the interstitial liquid. In one campaign, the rinsed sludge was dissolved in nitric acid to produce a solution containing total metal concentrations of ca. 1.8 M with a nitric acid concentration of ca. 2.9 M. About 50% of the dry mass of the sludge was dissolved. In the other campaign, the sludge was neutralized with nitric acid to destroy the carbonates, then leached with ca. 2.6 M NaOH for ca. 6 h before rinsing with the mild caustic. The sludge was then dissolved in nitric acid to produce a solution containing total metal concentrations of ca. 0.6 M with a nitric acid concentration of ca. 1.7 M. About 80% of the sludge dissolved. The dissolved sludge solution form the first campaign began gelling immediately, and a visible gel layer was observed after 8 days. In the second campaign, the solution became hazy after ca. 8 days, indicating gel formation, but did not display separated gel layers after aging for 20 days. Batch liquid-liquid equilibrium tests of both the extraction and stripping operations were conducted. Chemical analyses of both phases were used to evaluate the process. Evaluation was based on two metrics: the fraction of TRU elements removed from the dissolved sludge and comparison of the results with predictions made with the Generic TRUEX Model (GTM). The fractions of Eu, Pu, Cm, Th, and U species removed from aqueous solution in only one extraction stage were > 95% and were close to the values predicted by the GTM. Mercury was also found to be strongly extracted, with a one-stage removal of > 92%

  5. Removal and recovery of acetic acid and two furans during sugar purification of simulated phenols-free biomass hydrolysates.

    Science.gov (United States)

    Lee, Sang Cheol

    2017-12-01

    A cost-effective five-step sugar purification process involving simultaneous removal and recovery of fermentation inhibitors from biomass hydrolysates was first proposed here. Only the three separation steps (PB, PC and PD) in the process were investigated here. Furfural was selectively removed up to 98.4% from a simulated five-component hydrolysate in a cross-current three-stage extraction system with n-hexane. Most of acetic acid in a simulated four-component hydrolysate was selectively removed by emulsion liquid membrane, and it could be concentrated in the stripping solution up to 4.5 times its initial concentration in the feed solution. 5-Hydroxymethylfurfural was selectively removed from a simulated three-component hydrolysate in batch and continuous fixed-bed column adsorption systems with L-493 adsorbent. Also, 5-hydroxymethylfurfural could be concentrated to about 9 times its feed concentration in the continuous adsorption system through a fixed-bed column desorption experiment with aqueous ethanol solution. These results have shown that the proposed purification process was valid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Paraffin wax removal from metal injection moulded cocrmo alloy compact by solvent debinding process

    Science.gov (United States)

    Dandang, N. A. N.; Harun, W. S. W.; Khalil, N. Z.; Ahmad, A. H.; Romlay, F. R. M.; Johari, N. A.

    2017-10-01

    One of the most crucial and time consuming phase in metal injection moulding (MIM) process is “debinding”. These days, in metal injection moulding process, they had recounted that first debinding practice was depend on thermal binder degradation, which demanding more than 200 hours for complete removal of binder. Fortunately, these days world had introduced multi-stage debinding techniques to simplified the debinding time process. This research study variables for solvent debinding which are temperature and soaking time for samples made by MIM CoCrMo powder. Since wax as the key principal in the binder origination, paraffin wax will be removed together with stearic acid from the green bodies. Then, debinding process is conducted at 50, 60 and 70°C for 30-240 minutes. It is carried out in n-heptane solution. Percentage weight loss of the binder were measured. Lastly, scanning electron microscope (SEM) analysis and visual inspection were observed for the surface of brown compact. From the results, samples debound at 70°C exhibited a significant amount of binder loss; nevertheless, sample collapse, brittle surface and cracks were detected. But, at 60°C temperature and time of 4 hours proven finest results as it shows sufficient binder loss, nonappearance of surface cracks and easy to handle. Overall, binder loss is directly related to solvent debinding temperature and time.

  7. Performance of Fluidized bed Fenton process in Degrading Acid Blue 113

    Science.gov (United States)

    Bello, M. M.; Raman, A. A.

    2017-06-01

    The performance of a fluidized bed Fenton process in degrading Acid Blue 113 (AB 113) was investigated. Fluidized bed Fenton process is a modification of conventional Fenton oxidation, aimed at reducing sludge generation and improving process performance. Response surface methodology was used to study the effects of operational parameter on the color removal from the dye. Dimensionless factors, Dye/Fe2+, H2O2/Fe2+ and pH were used as the independent variables in Box-Behnken Design (BDD). Reduced quadratic model was developed to predict the color removal. The process could remove up to 99 % of the initial color. The most significant factor for color removal was found to be Dye/Fe2+, followed by H2O2/Fe2+. Unlike conventional Fenton, the initial pH of the solution does not have a significant effect on the color removal.

  8. Polycyclic aromatic hydrocarbon removal from contaminated soils using fatty acid methyl esters.

    Science.gov (United States)

    Gong, Zongqiang; Wang, Xiaoguang; Tu, Ying; Wu, Jinbao; Sun, Yifei; Li, Peng

    2010-03-01

    In this study, solubilization of PAHs from a manufactured gas plant (MGP) soil and two artificially spiked soils using fatty acid methyl esters (FAME) was investigated. PAH removals from both the MGP and the spiked soils by FAME, methanol, soybean oil, hydroxypropyl-beta-cyclodextrin, Triton X-100, and Tween 80 were compared. The effect of FAME:MGP soil ratios on PAH removals was also investigated. Results showed that the FAME mixture synthesized by our lab was more efficient than the cyclodextrin and the two surfactants used for PAH removal from the spiked soils with individual PAH concentrations of 200 and 400 mg kg(-1). However, the difference among three PAH removals by the FAME, soybean oil and methanol was not quite pronounced. The FAME synthesized and market biodiesel exhibited better performance for PAH removals (46% and 35% of total PAH) from the weathered contaminated MGP soil when compared with the other agents (0-31%). Individual PAH removals from the weathered MGP soil were much lower than those from the spiked soils. The percentages of total PAH removals from the MGP soil were 59%, 46%, and 51% for the FAME:MGP soil ratios of 1:2, 1:1, and 2:1, respectively. These results showed that the FAME could be a more attractive alternative to conventional surfactants in ex situ washing of PAH-contaminated soils. 2010 Elsevier Ltd. All rights reserved.

  9. Investigating the mechanism of clofibric acid removal in Fe(0)/H2O systems.

    Science.gov (United States)

    Ghauch, Antoine; Abou Assi, Hala; Tuqan, Almuthanna

    2010-04-15

    Since the introduction of iron wall technology, the inherent relationship between contaminant removal and iron corrosion has been mostly attributed to electron transfer from the metal body (direct reduction). This thermodynamically founded premise has failed to explain several experimental facts. Recently, a new concept considering adsorption and co-precipitation as fundamental contaminant removal mechanisms was introduced. This consistent concept has faced very skeptic views and necessarily needs experimental validation. The present work was the first independent attempt to validate the new concept using clofibric acid (CLO) as model compound. For this purpose, a powdered Fe(0) material (Fe(0)) was used in CLO removal experiments under various experimental conditions. Additional experiments were performed with plated Fe(0) (mFe(0): Fe(0)/Pd(0), Fe(0)/Ni(0)) to support the discussion of removal mechanism. Main investigated experimental variables included: abundance of O(2), abundance of iron corrosion products (ICPs) and shaking operations. Results corroborated the concept that quantitative contaminant removal in Fe(0)/H(2)O systems occurs within the oxide-film in the vicinity of Fe(0). Additionally, mixing type and shaking intensity significantly influenced the extent of CLO removal. More importantly, HPLC/MS revealed that the identity of reaction products depends on the extent of iron corrosion or the abundance of ICPs. The investigation of the CLO/Fe(0)/H(2)O system disproved the popular view that direct reduction mediates contaminant removal in the presence of Fe(0). 2009 Elsevier B.V. All rights reserved.

  10. Investigating the mechanism of clofibric acid removal in Fe0/H2O systems

    International Nuclear Information System (INIS)

    Ghauch, Antoine; Abou Assi, Hala; Tuqan, Almuthanna

    2010-01-01

    Since the introduction of iron wall technology, the inherent relationship between contaminant removal and iron corrosion has been mostly attributed to electron transfer from the metal body (direct reduction). This thermodynamically founded premise has failed to explain several experimental facts. Recently, a new concept considering adsorption and co-precipitation as fundamental contaminant removal mechanisms was introduced. This consistent concept has faced very skeptic views and necessarily needs experimental validation. The present work was the first independent attempt to validate the new concept using clofibric acid (CLO) as model compound. For this purpose, a powdered Fe 0 material (Fe 0 ) was used in CLO removal experiments under various experimental conditions. Additional experiments were performed with plated Fe 0 (mFe 0 : Fe 0 /Pd 0 , Fe 0 /Ni 0 ) to support the discussion of removal mechanism. Main investigated experimental variables included: abundance of O 2 , abundance of iron corrosion products (ICPs) and shaking operations. Results corroborated the concept that quantitative contaminant removal in Fe 0 /H 2 O systems occurs within the oxide-film in the vicinity of Fe 0 . Additionally, mixing type and shaking intensity significantly influenced the extent of CLO removal. More importantly, HPLC/MS revealed that the identity of reaction products depends on the extent of iron corrosion or the abundance of ICPs. The investigation of the CLO/Fe 0 /H 2 O system disproved the popular view that direct reduction mediates contaminant removal in the presence of Fe 0 .

  11. The use of carbon adsorbents for the removal of perfluoroalkyl acids from potable reuse systems.

    Science.gov (United States)

    Inyang, Mandu; Dickenson, Eric R V

    2017-10-01

    Bench- and pilot-scale sorption tests were used to probe the performance of several biochars at removing perfluoroalkyl acids (PFAA) from field waters, compared to granular activated carbon (GAC). Screening tests using organic matter-free water resulted in hardwood (HWC) (K d  = 41 L g -1 ) and pinewood (PWC) (K d  = 49 L g -1 ) biochars having the highest perfluorooctanoic acid (PFOA) removal performance that was comparable to bituminous coal GAC (K d  = 41 L g -1 ). PWC and HWC had a stronger affinity for PFOA sorbed in Lake Mead surface water (K F  = 11 mg (1-n) L n g -1 ) containing a lower (2 mg L -1 ) dissolved organic carbon (DOC) concentration than in a tertiary-filtered wastewater (K F  = 8 mg (1-n) L n g -1 ) with DOC of 4.9 mg L -1 . A pilot-scale study was performed using three parallel adsorbers (GAC, anthracite, and HWC biochar) treating the same tertiary-filtered wastewater. Compared to HWC, and anthracite, GAC was the most effective in mitigating perfluoropentanoic acid (PFPnA), perfluorohexanoic acid (PHxA), PFOA, perfluorooctane sulfonic acid (PFOS), and DOC (45-67% removed at 4354 bed volumes) followed by HWC, and then anthracite. Based on bench- and pilot-scale results, shorter-chain PFAA [perfluorobutanoic acid (PFBA), PFPnA, or PFHxA] were more difficult to remove with both biochar and GAC than the longer-chain, PFOS and PFOA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Changes in Phenolic Acid Content in Maize during Food Product Processing.

    Science.gov (United States)

    Butts-Wilmsmeyer, Carrie J; Mumm, Rita H; Rausch, Kent D; Kandhola, Gurshagan; Yana, Nicole A; Happ, Mary M; Ostezan, Alexandra; Wasmund, Matthew; Bohn, Martin O

    2018-04-04

    The notion that many nutrients and beneficial phytochemicals in maize are lost due to food product processing is common, but this has not been studied in detail for the phenolic acids. Information regarding changes in phenolic acid content throughout processing is highly valuable because some phenolic acids are chemopreventive agents of aging-related diseases. It is unknown when and why these changes in phenolic acid content might occur during processing, whether some maize genotypes might be more resistant to processing induced changes in phenolic acid content than other genotypes, or if processing affects the bioavailability of phenolic acids in maize-based food products. For this study, a laboratory-scale processing protocol was developed and used to process whole maize kernels into toasted cornflakes. High-throughput microscale wet-lab analyses were applied to determine the concentrations of soluble and insoluble-bound phenolic acids in samples of grain, three intermediate processing stages, and toasted cornflakes obtained from 12 ex-PVP maize inbreds and seven hybrids. In the grain, insoluble-bound ferulic acid was the most common phenolic acid, followed by insoluble-bound p-coumaric acid and soluble cinnamic acid, a precursor to the phenolic acids. Notably, the ferulic acid content was approximately 1950 μg/g, more than ten-times the concentration of many fruits and vegetables. Processing reduced the content of the phenolic acids regardless of the genotype. Most changes occurred during dry milling due to the removal of the bran. The concentration of bioavailable soluble ferulic and p-coumaric acid increased negligibly due to thermal stresses. Therefore, the current dry milling based processing techniques used to manufacture many maize-based foods, including breakfast cereals, are not conducive for increasing the content of bioavailable phenolics in processed maize food products. This suggests that while maize is an excellent source of phenolics, alternative

  13. Recovery of alumina from khushab bauxite by leaching with sulphuric acid and removal of iron impurity by ethanol

    International Nuclear Information System (INIS)

    Tariq, M.; Iqbal, M.M.; Shafiq, M.; Aziz, A.

    2014-01-01

    Bauxite is heterogeneous material principally composed of aluminum oxide minerals and found in all continents. It is being used in chemical, cement, refractory, abrasive, fertilizer, steel and other industries. In order to extract the alumina, the calcined samples of bauxite of Khushab area were ground to -710 meum. Sulphuric acid of purity 40% was used as leaching agent and slurry of pulp density 14% was prepared by dissolving 60 ml acid in 20 gm sample. The leaching was carried out at 90 degree C for 2 hours. The iron impurity was removed by ethanol of purity 68%. The drying, dehydration and desulphurization temperatures were kept 105 degree C, 450 degree C and 850 degree C respectively in all the stages of the process. Alumina recoveries from four samples of Sultan Mehdhi, Chamil More, Niaz Mine and Nadi locations were 20.8%, 9.81%, 15.47% and 7.78% respectively. Iron was almost completely removed as the analysis shows that the Fe/sub 2/O/sub 3/ removal was from 97.8% to 99.6%. It is concluded that leaching efficiency was quite encouraging except Nadi ore sample. However the iron free alumina recoveries were low as the analysis of Fe/sub 2/O/sub 3/ processed residue shows that it contains 72.72% to 92.94% of leached alumina in all the four experiments. (author)

  14. Technical Approach for the Development of a Near Tank Cesium Removal Process

    International Nuclear Information System (INIS)

    Sams, T.L.; Miller, Ch.E.; Kurath, D.E.; Blanchard, D.L.

    2009-01-01

    Parsons has been selected for development of two Advanced Remediation Technology (ART) projects. One of these projects is the Near Tank Cesium Removal (NTCR) project. The NTCR system uses the same basic ion exchange approach for Cs removal that has been used for decades in the nuclear industry. The essential difference in this approach is the development of a modular, mobile design concept based on a simplified process employing an advanced resin media and the use of cool nitric acid for elution and heated nitric acid for resin digestion. Under these conditions, the NTCR process shows significant improvements over the baseline ion exchange technology. These improvements will allow DOE to deploy a NTCR, free up tank space and accelerate closure of SSTs prior to Waste Treatment Plant Pretreatment Facility startup (WTP PTF). Current estimates indicate that the Hanford tank farm system will run out of available storage space prior to startup of the WTP PTF currently scheduled for 2019. The lack of tank space will constrain the near-term goal of retrieving waste from single-shell tanks prior to full operation of the WTP. A deployment of an NTCR system will allow LAW processing to begin as soon as supplemental treatment (e.g. Bulk Vitrification) or the WTP LAW Vitrification Facility becomes available. The NTCR system is a self contained modular, transportable system that requires only limited process chemicals and separates the HLW into two process streams. Once the cesium is removed, the low activity waste stream can be vitrified. The high activity stream would be stored in the DST system until vitrified by the WTP High Level Waste (HLW) Facility. This technology can be sized to feed the WTP LAW melters at the nominal operating capacity (30 MT glass per day. Alternatively, it could be sized to feed a supplemental treatment system such the Bulk Vitrification process. The NTCR system is based on an elutable ion exchange system using the Spherical Resorcinol Formaldehyde

  15. The microbial community in a high-temperature enhanced biological phosphorus removal (EBPR process

    Directory of Open Access Journals (Sweden)

    Ying Hui Ong

    2016-01-01

    Full Text Available An enhanced biological phosphorus removal (EBPR process operated at a relatively high temperature, 28 °C, removed 85% carbon and 99% phosphorus from wastewater over a period of two years. This study investigated its microbial community through fluorescent in situ hybridization (FISH and clone library generation. Through FISH, considerably more Candidatus “Accumulibacter phosphatis” (Accumulibacter-polyphosphate accumulating organisms (PAOs than Candidatus ‘Competibacter phosphatis’ (Competibacter-glycogen accumulating organisms were detected in the reactor, at 36 and 7% of total bacterial population, respectively. A low ratio of Glycogen/Volatile Fatty Acid of 0.69 further indicated the dominance of PAOs in the reactor. From clone library generated, 26 operational taxonomy units were retrieved from the sludge and a diverse population was shown, comprising Proteobacteria (69.6%, Actinobacteria (13.7%, Bacteroidetes (9.8%, Firmicutes (2.94%, Planctomycetes (1.96%, and Acidobacteria (1.47%. Accumulibacter are the only recognized PAOs revealed by the clone library. Both the clone library and FISH results strongly suggest that Accumulibacter are the major PAOs responsible for the phosphorus removal in this long-term EBPR at relatively high temperature.

  16. Nitrogen removal from coal gasification wastewater by activated carbon technologies combined with short-cut nitrogen removal process.

    Science.gov (United States)

    Zhao, Qian; Han, Hongjun; Hou, Baolin; Zhuang, Haifeng; Jia, Shengyong; Fang, Fang

    2014-11-01

    A system combining granular activated carbon and powdered activated carbon technologies along with shortcut biological nitrogen removal (GAC-PACT-SBNR) was developed to enhance total nitrogen (TN) removal for anaerobically treated coal gasification wastewater with less need for external carbon resources. The TN removal efficiency in SBNR was significantly improved by introducing the effluent from the GAC process into SBNR during the anoxic stage, with removal percentage increasing from 43.8%-49.6% to 68.8%-75.8%. However, the TN removal rate decreased with the progressive deterioration of GAC adsorption. After adding activated sludge to the GAC compartment, the granular carbon had a longer service-life and the demand for external carbon resources became lower. Eventually, the TN removal rate in SBNR was almost constant at approx. 43.3%, as compared to approx. 20.0% before seeding with sludge. In addition, the production of some alkalinity during the denitrification resulted in a net savings in alkalinity requirements for the nitrification reaction and refractory chemical oxygen demand (COD) degradation by autotrophic bacteria in SBNR under oxic conditions. PACT showed excellent resilience to increasing organic loadings. The microbial community analysis revealed that the PACT had a greater variety of bacterial taxons and the dominant species associated with the three compartments were in good agreement with the removal of typical pollutants. The study demonstrated that pre-adsorption by the GAC-sludge process could be a technically and economically feasible method to enhance TN removal in coal gasification wastewater (CGW). Copyright © 2014. Published by Elsevier B.V.

  17. Fate of aliphatic compounds in nitric acid processing solutions

    International Nuclear Information System (INIS)

    Clark, W.E.; Howerton, W.B.

    1975-01-01

    The reaction of hyperazeotropic iodic acid-saturated nitric acid with short chain aliphatic iodides, nitrates, and acids was studied in order to determine the conditions for complete removal of organic materials from nitric acid systems. The aliphatic iodides are converted to the nitrates and the nitrates in strong HNO 3 are extensively converted into CO 2 and acids. The aliphatic acids are rather stable; acetic acid was unattacked by boiling in 20M HNO 3 and n-butyric acid was 80 percent unattacked. The dibasic acids oxalic and malonic are extensively attacked, but succinic acid is relatively stable. A wet oxidation method is successful in destroying acetic acid in 5 to 8M HNO 3 . (U.S.)

  18. Denitrification of acid wastes from uranium purification processes

    International Nuclear Information System (INIS)

    Clark, F.E.; Francis, C.W.; Francke, H.C.; Strohecker, J.W.

    1975-11-01

    Laboratory and pilot-plant investigations have shown the technical feasibility of removing nitrates from neutralized acid wastes from uranium purification processes by biological denitrification, a dissimilatory process in which the nitrate ion is reduced to nitrogen gas by specific bacteria. The process requires anaerobic conditions and an organic carbon source, as well as other life-sustaining constituents. These denitrification studies produced process design information on a columnar denitrification plant and on continuous-flow, stirred-bed reactors. Denitrification, using packed columns, was found to be desirable for soluble salts, such as those of sodium and ammonium; denitrification, using stirred reactors, was found to be desirable for mixtures containing insoluble salts, such as those of calcium and aluminum. Packed columns were found to have denitrification rates ranging up to 122 grams of nitrate per day per cubic decimeter of column volume; stirred-bed reactors have been shown to have reaction rates near 10 grams of nitrate per day per cubic decimeter of reactor volume. The continuous-flow, stirred-bed reactors were selected for scaleup studies because of the solids-removal problems associated with packed columns when operating on feeds containing high concentrations of insoluble salts or ions which form insoluble salts with the products of the denitrification reaction

  19. Pilot-scale field study for ammonia removal from lagoon biogas using an acid wet scrubber.

    Science.gov (United States)

    Lin, Hongjian; Wu, Xiao; Miller, Curtis; Zhu, Jun; Hadlocon, Lara Jane; Manuzon, Roderick; Zhao, Lingying

    2014-01-01

    The anaerobic activities in swine slurry storage and treatment generate biogas containing gaseous ammonia component which is a chemical agent that can cause adverse environmental impacts when released to the atmosphere. The aim of this pilot plant study was to remove ammonia from biogas generated in a covered lagoon, using a sulfuric acid wet scrubber. The data showed that, on average, the biogas contained 43.7 ppm of ammonia and its concentration was found to be exponentially related to the air temperature inside the lagoon. When the air temperature rose to 35°C and the biogas ammonia concentration reached 90 ppm, the mass transfer of ammonia/ammonium from the deeper liquid body to the interface between the air and liquid became a limiting factor. The biogas velocity was critical in affecting ammonia removal efficiency of the wet scrubber. A biogas flow velocity of 8 to 12 mm s(-1) was recommended to achieve a removal efficiency of greater than 60%. Stepwise regression revealed that the biogas velocity and air temperature, not the inlet ammonia concentration in biogas, affected the ammonia removal efficiency. Overall, when 73 g L(-1) (or 0.75 M) sulfuric acid solution was used as the scrubber solution, removal efficiencies varied from 0% to 100% with an average of 55% over a 40-d measurement period. Mass balance calculation based on ammonium-nitrogen concentration in final scrubber liquid showed that about 21.3 g of ammonia was collected from a total volume of 1169 m(3) of biogas, while the scrubber solution should still maintain its ammonia absorbing ability until its concentration reaches up to 1 M. These results showed promising use of sulfuric acid wet scrubber for ammonia removal in the digester biogas.

  20. Application of acoustic agglomeration for removing sulfuric acid mist from air stream

    Directory of Open Access Journals (Sweden)

    Asghar Sadighzadeh

    2018-01-01

    Full Text Available The application of acoustic fields at high sound pressure levels (SPLs for removing sulfuric acid mists from the air stream was studied. An acoustic agglomeration chamber was used to conduct the experiments. The studied SPLs ranged from 115 to 165 decibel (dB, with three inlet concentrations of acid mist at 5–10, 15–20, and 25–30 ppm. The air flow rates for conducting experiments were 20, 30, and 40 L min−1. The concentration of sulfuric acid mist was measured using US Environmental Protection Agency Method 8 at inlet and outlet of the chamber. The resonance frequencies for experiments were found to be 852, 1410, and 3530 Hz. The maximum acoustic agglomeration efficiency of 86% was obtained at optimum frequency of 852 Hz. The analysis of variance test revealed significant differences between agglomeration efficiency at three resonance frequencies (p-value < 0.001. The maximum acoustic agglomeration efficiency was obtained at SPL level of 165 dB. High initial concentrations of acid mists and lower air flow rates enhance the acoustic agglomeration of mists. High removal efficiency of acid mists from air stream could be achieved by the application of acoustic agglomeration method with appropriate range of frequencies and SPLs. Keywords: Sulfuric acid, Mist, Acoustic agglomeration, SPL

  1. Optimization of the operation of packed bed bioreactor to improve the sulfate and metal removal from acid mine drainage.

    Science.gov (United States)

    Dev, Subhabrata; Roy, Shantonu; Bhattacharya, Jayanta

    2017-09-15

    The present study discusses the potentiality of using anaerobic Packed Bed Bioreactor (PBR) for the treatment of acid mine drainage (AMD). The multiple process parameters such as pH, hydraulic retention time (HRT), concentration of marine waste extract (MWE), total organic carbon (TOC) and sulfate were optimized together using Taguchi design. The order of influence of the parameters towards biological sulfate reduction was found to be pH > MWE > sulfate > HRT > TOC. At optimized conditions (pH - 7, 20% (v/v) MWE, 1500 mg/L sulfate, 48 h HRT and 2300 mg/L TOC), 98.3% and 95% sulfate at a rate of 769.7 mg/L/d. and 732.1 mg/L/d. was removed from the AMD collected from coal and metal mine, respectively. Efficiency of metal removal (Fe, Cu, Zn, Mg and Ni) was in the range of 94-98%. The levels of contaminants in the treated effluent were below the minimum permissible limits of industrial discharge as proposed by Bureau of Indian Standards (IS 2490:1981). The present study establishes the optimized conditions for PBR operation to completely remove sulfate and metal removal from AMD at high rate. The study also creates the future scope to develop an efficient treatment process for sulfate and metal-rich mine wastewater in a large scale. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Use of Polymeric and Natural Materials for the Removal of Irradiated Direct and acid Dyes from Effluents

    International Nuclear Information System (INIS)

    Dessouki, A.M.; Abdel-Aal, S.E.; Gad, Y.H.

    2000-01-01

    Wastewater effluents from textile plants typically contain appreciable quantities of organic dyes that are resistant to degrade by ordinary treatment processes and constitute a highly visible form of pollution in the receiving waters. Carbon absorption as well as ionizing radiation are used as treatment processes. However, each method alone did not achieve the complete removal of these pollutants. A combined treatment is more effective. The two direct dyes(Direct orange S, Isma fast yellow Rl) were degraded by radiation 76% and 70% ,respectively. Also, the acid dye Sandolane Rubanole E-3 GSL (Acid red 37) was degraded almost to the same extent. Addition of O 2 or H 2 O-2 resulted in a remarkable enhancement in the degradation process. The effect of ph, gamma-dose and dye concentration was studied. Polymeric ion exchangers proved to be more effective in the removal process than clays. However, granular activated carbon (GAC) was the best adsorbent for the direct dyes. Clays proved to be very good adsorbents for two basic dyes than their weak adsorption behavior of the direct ones

  3. Auto-recognition of surfaces and auto-generation of material removal volume for finishing process

    Science.gov (United States)

    Kataraki, Pramod S.; Salman Abu Mansor, Mohd

    2018-03-01

    Auto-recognition of a surface and auto-generation of material removal volumes for the so recognised surfaces has become a need to achieve successful downstream manufacturing activities like automated process planning and scheduling. Few researchers have contributed to generation of material removal volume for a product but resulted in material removal volume discontinuity between two adjacent material removal volumes generated from two adjacent faces that form convex geometry. The need for limitation free material removal volume generation was attempted and an algorithm that automatically recognises computer aided design (CAD) model’s surface and also auto-generate material removal volume for finishing process of the recognised surfaces was developed. The surfaces of CAD model are successfully recognised by the developed algorithm and required material removal volume is obtained. The material removal volume discontinuity limitation that occurred in fewer studies is eliminated.

  4. Investigation of As(V) removal from acid mine drainage by iron (hydr) oxide modified zeolite.

    Science.gov (United States)

    Nekhunguni, Pfano Mathews; Tavengwa, Nikita Tawanda; Tutu, Hlanganani

    2017-07-15

    In this work, the synthesis of iron (hydr) oxide modified zeolite was achieved through precipitation of iron on the zeolite. The structure and surface morphology of iron (hydr) oxide modified zeolite (IHOMZ) was studied by scanning electron microscopy (SEM), coupled with an energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectra. The efficiency of IHOMZ was then investigated through batch technique for the extraction of As(V) from mine waste water. The optimum parameters for maximum As(V) adsorption were: an initial As(V) concentration (10 mg L -1 ), adsorbent dosage (3.0 g), contact time (90 min) and temperature (53 °C). The initial pH of the solution had no compelling effect on As(V) adsorption by IHOMZ. However, adsorption capacity was significantly affected by the solution temperature with 53 °C registering the maximum removal efficiency. The thermodynamic parameters: Entropy (ΔS° = 0.00815 kJ (K mol) -1 ), variation of the Gibbs free energy (ΔG°) and enthalpy (ΔH° = 9.392 kJ mol -1 ) of As(V) adsorption onto IHOMZ system signified a non-spontaneous and endothermic process. It was noted that Freundlich isotherm model exhibited a better fit to the equilibrium experimental data, implying that the adsorption process occurred on a heterogeneous surface. The kinetic data from As(V) adsorption experiments was depicted by the pseudo-second-order kinetic model (R 2  > 0.999), suggesting a chemisorption adsorption process. The experimental batch equilibrium results indicated that IHOMZ could be used as an effective sorbent for As(V) ion extraction from acid mine drainage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Biological nitrate removal from water and wastewater by solid-phase denitrification process.

    Science.gov (United States)

    Wang, Jianlong; Chu, Libing

    2016-11-01

    Nitrate pollution in receiving waters has become a serious issue worldwide. Solid-phase denitrification process is an emerging technology, which has received increasing attention in recent years. It uses biodegradable polymers as both the carbon source and biofilm carrier for denitrifying microorganisms. A vast array of natural and synthetic biopolymers, including woodchips, sawdust, straw, cotton, maize cobs, seaweed, bark, polyhydroxyalkanoate (PHA), polycaprolactone (PCL), polybutylene succinate (PBS) and polylactic acid (PLA), have been widely used for denitrification due to their good performance, low cost and large available quantities. This paper presents an overview on the application of solid-phase denitrification in nitrate removal from drinking water, groundwater, aquaculture wastewater, the secondary effluent and wastewater with low C/N ratio. The types of solid carbon source, the influencing factors, the microbial community of biofilm attached on the biodegradable carriers, the potential adverse effect, and the cost of denitrification process are introduced and evaluated. Woodchips and polycaprolactone are the popular and competitive natural plant-like and synthetic biodegradable polymers used for denitrification, respectively. Most of the denitrifiers reported in solid-phase denitrification affiliated to the family Comamonadaceae in the class Betaproteobacteria. The members of genera Diaphorobacter, Acidovorax and Simplicispira were mostly reported. In future study, more attention should be paid to the simultaneous removal of nitrate and toxic organic contaminants such as pesticide and PPCPs by solid-phase denitrification, to the elucidation of the metabolic and regulatory relationship between decomposition of solid carbon source and denitrification, and to the post-treatment of the municipal secondary effluent. Solid-phase denitrification process is a promising technology for the removal of nitrate from water and wastewater. Copyright © 2016

  6. Thief process for the removal of mercury from flue gas

    Science.gov (United States)

    Pennline, Henry W.; Granite, Evan J.; Freeman, Mark C.; Hargis, Richard A.; O'Dowd, William J.

    2003-02-18

    A system and method for removing mercury from the flue gas of a coal-fired power plant is described. Mercury removal is by adsorption onto a thermally activated sorbent produced in-situ at the power plant. To obtain the thermally activated sorbent, a lance (thief) is inserted into a location within the combustion zone of the combustion chamber and extracts a mixture of semi-combusted coal and gas. The semi-combusted coal has adsorptive properties suitable for the removal of elemental and oxidized mercury. The mixture of semi-combusted coal and gas is separated into a stream of gas and semi-combusted coal that has been converted to a stream of thermally activated sorbent. The separated stream of gas is recycled to the combustion chamber. The thermally activated sorbent is injected into the duct work of the power plant at a location downstream from the exit port of the combustion chamber. Mercury within the flue gas contacts and adsorbs onto the thermally activated sorbent. The sorbent-mercury combination is removed from the plant by a particulate collection system.

  7. Uranium removal from acidic aqueous solutions by Saccharomyces cerevisiae, Debaryomyces hansenii, Kluyveromyces marxianus and Candida colliculosa

    International Nuclear Information System (INIS)

    Sarri, S.; Misaelides, P.; Papanikolaou, M.; Zamboulis, D.

    2009-01-01

    The sorption of uranium from acidic aqueous solutions (pH 4.5, C init = 10 to 1000 mg U/L) by Saccharomyces cerevisiae, Debaryomyces hansenii, Kluyveromyces marxianus and Candida colliculosa was investigated using a batch technique. The U-sorption onto Saccharomyces cerevisiae and Debaryomyces hansenii followed a Langmuir, while that onto Kluyveromyces marxianus and Candida colliculosa a Freundlich isotherm. The results demonstrated that all investigated biomasses could effectively remove uranium from acidic aqueous solutions. From all sorbents, Saccharomyces cerevisiae appeared to be the most effective with a maximum sorption capacity of 127.7 mg U/g dry biomass. (author)

  8. A Study on the Removal of Cesium in Soil Contaminated with Radiation Using a Soil Washing Process

    International Nuclear Information System (INIS)

    Park, Ukryang; Kim, Gyenam; Kim, Seungsoo; Park, Hyemin; Kim, Wansuk; Moon, Jaikwon

    2013-01-01

    The first principle is related with the washing process which is carried out to transfer the contaminated mass from the soil to water by dissolving it with a cleansing solution. The second is concerned with the size of the separation process which focuses on the reduction of the volume by separating the subject matters based on the different sizes of the soil. The complex agents used in the soil washing process include HCl, Oxalic acid, Citric acid, CaCl 2 , BaCl 2 , NH 4 NO 3 , and NaOH. It is known that the complex-forming capacity of such complex agents and radionuclides influences the decontamination from the soil. Also, since the forms of the chemical species related with the complex agents and the surface potential of the soil vary based on the changes of acidity observed in the cleansing solution, the level of acidity in the cleansing solution can be regarded as a factor that influences the decontamination. Therefore, in this study, H 2 SO 4 was selected as the complex agent and used to check the influence of the temperature when the subject contaminated soil was washed. Then, by applying the sieve grading process with a sieve-shaker, the size separation process was carried out to measure the level of radiation for each size. By washing the contaminated soil separated into different sizes with the complex agent H 2 SO 4 , the different removal tendencies for each size were considered. After selecting the complex agent H 2 SO 4 and checking the influence of temperature when the contaminated soil was washed based on the solid-liquid ratio of 1g:2ml, it was found that the heat washing process at a temperature of 95 .deg. C showed a higher level of efficiency for the removal of Cs compared to the case of the non-heat washing process. Also, according to the results given by the process of considering the different removal tendencies for each size based on the heat washing process after the sieve grading process was applied with the sieve-shaker prior for the size

  9. A Study on the Removal of Cesium in Soil Contaminated with Radiation Using a Soil Washing Process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ukryang; Kim, Gyenam; Kim, Seungsoo; Park, Hyemin; Kim, Wansuk; Moon, Jaikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    The first principle is related with the washing process which is carried out to transfer the contaminated mass from the soil to water by dissolving it with a cleansing solution. The second is concerned with the size of the separation process which focuses on the reduction of the volume by separating the subject matters based on the different sizes of the soil. The complex agents used in the soil washing process include HCl, Oxalic acid, Citric acid, CaCl{sub 2}, BaCl{sub 2}, NH{sub 4}NO{sub 3}, and NaOH. It is known that the complex-forming capacity of such complex agents and radionuclides influences the decontamination from the soil. Also, since the forms of the chemical species related with the complex agents and the surface potential of the soil vary based on the changes of acidity observed in the cleansing solution, the level of acidity in the cleansing solution can be regarded as a factor that influences the decontamination. Therefore, in this study, H{sub 2}SO{sub 4} was selected as the complex agent and used to check the influence of the temperature when the subject contaminated soil was washed. Then, by applying the sieve grading process with a sieve-shaker, the size separation process was carried out to measure the level of radiation for each size. By washing the contaminated soil separated into different sizes with the complex agent H{sub 2}SO{sub 4}, the different removal tendencies for each size were considered. After selecting the complex agent H{sub 2}SO{sub 4} and checking the influence of temperature when the contaminated soil was washed based on the solid-liquid ratio of 1g:2ml, it was found that the heat washing process at a temperature of 95 .deg. C showed a higher level of efficiency for the removal of Cs compared to the case of the non-heat washing process. Also, according to the results given by the process of considering the different removal tendencies for each size based on the heat washing process after the sieve grading process was

  10. Adsorptive removal of naproxen and clofibric acid from water using metal-organic frameworks.

    Science.gov (United States)

    Hasan, Zubair; Jeon, Jaewoo; Jhung, Sung Hwa

    2012-03-30

    Adsorptive removal of naproxen and clofibric acid, two typical PPCPs (pharmaceuticals and personal care products), has been studied using metal-organic frameworks (MOFs) for the first time. The removal efficiency decreases in the order of MIL-101>MIL-100-Fe>activated carbon both in adsorption rate and adsorption capacity. The adsorption kinetics and capacity of PPCPs generally depend on the average pore size and surface area (or pore volume), respectively, of the adsorbents. The adsorption mechanism may be explained with a simple electrostatic interaction between PPCPs and the adsorbent. Finally, it can be suggested that MOFs having high porosity and large pore size can be potential adsorbents to remove harmful PPCPs in contaminated water. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Thermodynamic analysis of stability in iron removal from kaolin by using oxalic acid

    Directory of Open Access Journals (Sweden)

    C. Ocampo-López

    2013-06-01

    Full Text Available The graphical representation of global stability for a system, or Pourbaix diagram, was constructed to perform a thermodynamic study of iron removal from kaolin using oxalic acid as an oxidant. To do this the free energies of formation of the oxalate complex of the system were calculated, and it was found that the more stable specie is Fe(C2O43-3, with a calculated free energy of formation of -3753.88 kcal/mol. Thermodynamic stability functions were estimated for the system as a function of pH and Eh known as potential of oxide reduction. It was built a global stability diagram for the removal system; it showed that the specie trioxalate Fe(C2O43-3 is the only oxalate in equilibrium with other compounds associated with the removal of iron in kaolin.

  12. Citric-acid preacidification enhanced electrokinetic remediation for removal of chromium from chromium-residue-contaminated soil.

    Science.gov (United States)

    Meng, Fansheng; Xue, Hao; Wang, Yeyao; Zheng, Binghui; Wang, Juling

    2018-02-01

    Electrokinetic experiments were conducted on chromium-residue-contaminated soils collected from a chemical plant in China. Acidification-electrokinetic remediation technology was proposed in order to solve the problem of removing inefficient with ordinary electrokinetic. The results showed that electrokinetic remediation removal efficiency of chromium from chromium-contaminated soil was significantly enhanced with acidizing pretreatment. The total chromium [Cr(T)] and hexavalent chromium [Cr(VI)] removal rate of the group acidized by citric acid (0.9 mol/L) for 5 days was increased from 6.23% and 19.01% in the acid-free experiments to 26.97% and 77.66% in the acidification-treated experiments, respectively. In addition, part of chromium with the state of carbonate-combined will be converted into water-soluble state through acidification to improve the removal efficiency. Within the appropriate concentration range, the higher concentration of acid was, the more chromium was released. So the removal efficiency of chromium depended on the acid concentration. The citric acid is also a kind of complexing agent, which produced complexation with Cr that was released by the electrokinetic treatment and then enhanced the removal efficiency. The major speciation of chromium that was removed from soils by acidification-electrokinetics remediation was acid-soluble speciation, revivification speciation and oxidation speciation, which reduced biological availability of chromium.

  13. Removal of Pb(II) from water by the activated carbon modified by nitric acid under microwave heating.

    Science.gov (United States)

    Yao, Shuheng; Zhang, Jiajun; Shen, Dekui; Xiao, Rui; Gu, Sai; Zhao, Ming; Liang, Junyu

    2016-02-01

    The rice husk based activated carbon (RH-AC) was treated by nitric acid under microwave heating, in order to improve its capability for the removal of heavy metal ions from water. The optimal conditions for the modification of RH-AC (M-RH-AC) were determined by means of orthogonal array experimental design, giving those as the concentration of nitric acid of 8mol/L, modification time of 15min, modification temperature of 130°C and microwave power of 800W. The characteristics of the M-RH-AC and RH-AC were examined by BET, XRD, Raman spectrum, pH titration, zeta potential, Boehm titration and FTIR analysis. The M-RH-AC has lower pore surface area, smaller crystallite, lower pHIEP and more oxygen-containing functional groups than the RH-AC. Removal capacity of Pb(II) ions by the M-RH-AC and RH-AC from water solution was estimated concerning the influence of contact time, pH value, and initial concentration. The equilibrium time of Pb(II) removal was found to be around 90min after modification process. Two kinetic models are adopted to describe the possible Pb(II) adsorption mechanism, finding that the adsorption rate of Pb(II) ions by the M-RH-AC is larger than that of RH-AC. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Cleaner production of citric acid by recycling its extraction wastewater treated with anaerobic digestion and electrodialysis in an integrated citric acid-methane production process.

    Science.gov (United States)

    Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the pollution problem of extraction wastewater in citric acid production, an integrated citric acid-methane production process was proposed. Extraction wastewater was treated through anaerobic digestion and the anaerobic digestion effluent (ADE) was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. Excessive Na(+) contained in ADE could significantly inhibit citric acid fermentation in recycling and was removed by electrodialysis in this paper. Electrodialysis performance was improved after pretreatment of ADE with air stripping and activated carbon adsorption to remove precipitable metal ions and pigments. Moreover, the concentrate water was recycled and mixed with feed to improve the water recovery rate above 95% in electrodialysis treatment, while the dilute water was collected for citric acid fermentation. The removal rate of Na(+) in ADE was above 95% and the citric acid production was even higher than that with tap water. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Reuse of acid coagulant-recovered drinking waterworks sludge residual to remove phosphorus from wastewater

    Science.gov (United States)

    Yang, Lan; Wei, Jie; Zhang, Yumei; Wang, Jianli; Wang, Dongtian

    2014-06-01

    Acid coagulant-recovered drinking waterworks sludge residual (DWSR) is a waste product from drinking waterworks sludge (DWS) treatment with acid for coagulant recovery. In this study, we evaluated DWSR as a potential phosphorus (P) removing material in wastewater treatment by conducting a series of batch and semi-continuous tests. Batch tests were carried out to study the effects of pH, initial concentration, and sludge dose on P removal. Batch test results showed that the P removal efficiency of DWSR was highly dependent on pH. Calcinated DWSR (C-DWSR) performed better in P removal than DWSR due to its higher pH. At an optimum initial pH value of 5-6 and a sludge dose of 10 g/L, the P removal rates of DWSR and DWS decreased from 99% and 93% to 84% and 14%, respectively, and the specific P uptake of DWSR and DWS increased from 0.19 and 0.19 mg P/g to 33.60 and 5.72 mg P/g, respectively, when the initial concentration was increased from 2 to 400 mg/L. The effective minimum sludge doses of DWSR and DWS were 0.5 g/L and 10 g/L, respectively, when the P removal rates of 90% were obtained at an initial concentration of 10 mg/L. Results from semi-continuous test indicated that P removal rates over 99% were quickly achieved for both synthetic and actual wastewater (lake water and domestic sewage). These rates could be maintained over a certain time under a certain operational conditions including sludge dose, feed flow, and initial concentration. The physicochemical properties analysis results showed that the contents of aluminum (Al) and iron (Fe) in DWSR were reduced by 50% and 70%, respectively, compared with DWS. The insoluble Al and Fe hydroxide in DWS converted into soluble Al and Fe in DWSR. Metal leaching test results revealed that little soluble Al and Fe remained in effluent when DWSR was used for P removal. We deduced that chemical precipitation might be the major action for P removal by DWSR and that adsorption played only a marginal role.

  16. Energy saving processes for nitrogen removal in organic wastewater from food processing industries in Thailand.

    Science.gov (United States)

    Johansen, N H; Suksawad, N; Balslev, P

    2004-01-01

    Nitrogen removal from organic wastewater is becoming a demand in developed communities. The use of nitrite as intermediate in the treatment of wastewater has been largely ignored, but is actually a relevant energy saving process compared to conventional nitrification/denitrification using nitrate as intermediate. Full-scale results and pilot-scale results using this process are presented. The process needs some additional process considerations and process control to be utilized. Especially under tropical conditions the nitritation process will round easily, and it must be expected that many AS treatment plants in the food industry already produce NO2-N. This uncontrolled nitrogen conversion can be the main cause for sludge bulking problems. It is expected that sludge bulking problems in many cases can be solved just by changing the process control in order to run a more consequent nitritation. Theoretically this process will decrease the oxygen consumption for oxidation by 25% and the use of carbon source for the reduction will be decreased by 40% compared to the conventional process.

  17. Applications of digital processing for noise removal from plasma diagnostics

    International Nuclear Information System (INIS)

    Kane, R.J.; Candy, J.V.; Casper, T.A.

    1985-01-01

    The use of digital signal techniques for removal of noise components present in plasma diagnostic signals is discussed, particularly with reference to diamagnetic loop signals. These signals contain noise due to power supply ripple in addition to plasma characteristics. The application of noise canceling techniques, such as adaptive noise canceling and model-based estimation, will be discussed. The use of computer codes such as SIG is described. 19 refs., 5 figs

  18. Zinc removal from wastewater by complexation-microfiltration process

    OpenAIRE

    Trivunac Katarina; Sekulić Zoran; Stevanović Slavica

    2012-01-01

    As a result of its wide industrial applications, zinc has become an important contaminant in aquatic environment since it is a toxic heavy metal and some of its compounds such as zinc arsenate and zinc cyanide, may be extremely hazardous. Therefore, there is a growing need for developing simple methods capable of separating and recovering trace zinc from environmental waters. Nowadays, the ultra and microfiltration method for trace metals removal from waters by the addition of water-sol...

  19. Removing radioactive noble gases from nuclear process off-gases

    International Nuclear Information System (INIS)

    Lofredo, A.

    1977-01-01

    A system is claimed for separating, concentrating and storing radioactive krypton and xenon in the off-gases from a boiling water reactor, wherein adsorption and cryogenic distillation are both efficiently used for rapid and positive separation and removal of the radioactive noble gases, and for limiting such gases in circulation in the system to low inventory at all times, and wherein the system is self-regulating to eliminate operator options or attention

  20. Recent studies of uranium recovery from wet-process phosphoric acid with octylphenyl acid phosphate

    International Nuclear Information System (INIS)

    Arnold, W.D.

    1978-01-01

    Commercial OPAP is a complex mixture that contains at least 11 components. Octyl phenol is the principal impurity. Commercial OPAP contains readily-hydrolyzable material. The concentrations of octyl phenol and an unidentified impurity increase in the hydrolyzed product. Uranium extraction power is decreased slightly by hydrolysis of the reagent. Four major problems were encountered in continuous stability tests: (1) Microemulsion or micelle formation--loss of organic phase into phosphoric acid. We do not have a solution to this problem at this time. It could involve alteration of the organic, e.g., adding a modifier, changing the reagent structure, or changing the diluent. (2) Reagent poisoning--reduction of uranium extraction and interference with organic titrations by material extracted from the acid. Additional work is needed to identify the poisoning material or materials. It can then be removed if it originates in the phosphate rock, or avoided if it originates in chemicals added during processing. (3) Crystallization with iron--loss of both major components of the reagent as a complex with ferric iron. We believe this problem can be controlled by controlling the ferric iron concentration in the phosphoric acid. (4) MOPPA distribution loss--a selective loss to the aqueous phase. We believe this can be minimized by controlling the iron concentration of the phosphoric acid. The iron concentration will need to be kept low enough to avoid reagent crystallization and high enough to avoid MOPPA distribution loss. 15 figs

  1. Process for off-gas particulate removal and apparatus therefor

    International Nuclear Information System (INIS)

    Carl, D.E.

    1997-01-01

    In the event of a breach in the off-gas line of a melter operation requiring closure of the line, a secondary vessel vent line is provided with a particulate collector utilizing atomization for removal of large particulates from the off-gas. The collector receives the gas containing particulates and directs a portion of the gas through outer and inner annular channels. The collector further receives a fluid, such as water, which is directed through the outer channel together with a second portion of the particulate-laden gas. The outer and inner channels have respective ring-like termination apertures concentrically disposed adjacent one another on the outer edge of the downstream side of the particulate collector. Each of the outer and inner channels curves outwardly away from the collector's centerline in proceeding toward the downstream side of the collector. Gas flow in the outer channel maintains the fluid on the channel's wall in the form of a ''wavy film,'' while the gas stream from the inner channel shears the fluid film as it exits the outer channel in reducing the fluid to small droplets. Droplets formed by the collector capture particulates in the gas stream by one of three mechanisms: impaction, interception or Brownian diffusion in removing the particulates. The particulate-laden droplets are removed from the fluid stream by a vessel vent condenser or mist eliminator. 4 figs

  2. Removal of heavy metals from polluted soil using the citric acid fermentation broth: a promising washing agent.

    Science.gov (United States)

    Zhang, Hongjiao; Gao, Yuntao; Xiong, Huabin

    2017-04-01

    The citric acid fermentation broth was prepared and it was employed to washing remediation of heavy metal-polluted soil. A well-defined washing effect was obtained, the removal percentages using citric acid fermentation broth are that 48.2% for Pb, 30.6% for Cu, 43.7% for Cr, and 58.4% for Cd and higher than that using citric acid solution. The kinetics of heavy metals desorption can be described by the double constant equation and Elovich equation and is a heterogeneous diffusion process. The speciation analysis shows that the citric acid fermentation broth can effectively reduce bioavailability and environmental risk of heavy metals. Spectroscopy characteristics analysis suggests that the washing method has only a small effect on the mineral composition and does not destroy the framework of soil system. Therefore, the citric acid fermentation broth is a promising washing agent and possesses a potential practical application value in the field of remediation of soils with a good washing performance.

  3. Coagulant properties of Moringa oleifera protein preparations: application to humic acid removal.

    Science.gov (United States)

    Santos, Andréa F S; Paiva, Patrícia M G; Teixeira, José A C; Brito, António G; Coelho, Luana C B B; Nogueira, Regina

    2012-01-01

    This work aimed to characterize the coagulant properties of protein preparations from Moringa oleifera seeds in the removal of humic acids from water. Three distinct preparations were assayed, namely extract (seeds homogenized with 0.15 M NaCl), fraction (extract precipitated with 60% w/v ammonium sulphate) and cMoL (protein purified with guar gel column chromatography). The extract showed the highest coagulant activity in a protein concentration between 1 mg/L and 180 mg/L at pH 7.0. The zeta potential of the extract (-10 mV to -15 mV) was less negative than that of the humic acid (-41 mV to -42 mV) in a pH range between 5.0 and 8.0; thus, the mechanism that might be involved in this coagulation activity is adsorption and neutralization of charges. Reduction of total organic carbon (TOC) and dissolved organic carbon (DOC) was observed in water samples containing 9 mg/L carbon as humic acid when treated with 1 mg/L of the extract. A decrease in colour and in the aromatic content of the treated water was also observed. These results suggested that the extract from M. oleifera seeds in a low concentration (1 mg/L) can be an interesting natural alternative for removing humic acid from water in developing countries. The extract dose determined in the present study does not impart odour or colour to the treated water.

  4. Removal of Radium-226 from Radium-Contaminated Soil using Distilled Water and Humic Acid: Effect of pH

    International Nuclear Information System (INIS)

    Phillips, E.; Muhammad Samudi Yasir; Muhamat Omar

    2011-01-01

    Effect of washing solutions' pH removal of radium-226 from radium-contaminated soil using distilled water and humic acid extracted from Malaysian peat soil was studied by batch washing method. The study encompassed the extraction of humic acid and the washing of radium-contaminated soil using distilled water and humic acid solutions of 100 ppm, both with varying pHs in the range of 3 to 11. The radioactivity concentration of radium-226 was determined by gamma spectrometer.The removal of radium-226 was greater when humic acid solutions were used compared to distilled water at the pH range studied and both washing solutions showed greater removal of radium-226 when basic solutions were used. Nevertheless, comparable removal efficiencies were observed when neutral and highly basic humic acid solutions were used. (author)

  5. Removal of radionuclides from process streams, a series of applications

    International Nuclear Information System (INIS)

    Menetrez, M.Y.

    1987-01-01

    The extensive research performed on metal oxide adsorption, the adsorption phenomena and physical conditions of cationic adsorption on manganese dioxide in solution have demonstrated that above pH 3 cations are adsorbed by an order of affinity, and that the interaction is characterized by the pH dependence of the metal. The relationship of the zero point charge of pH and the solution ionic strength effects on interfacial surface potential and adsorption have been addressed. A system to produce MnO 2 fiber with a heavy MnO 2 loading was designed, constructed, and operated successfully. Extensive testing has been performed on the adsorption of radium, calcium, cadmium, cesium, cobalt, iron, and manganese on MnO 2 fiber. This testing entailed field work utilizing bleed stream tests of MnO 2 fiber cartridges and tests of loose MnO 2 fiber and resin in columns. Radium removal amounted to a level of 36.9 nanocuries per gram MnO 2 , or 2 microcuries on a single 10 inch MnO 2 fiber filter element. Removal of metals from solutions was demonstrated at various rates specific for each metal tested. The order of affinity of those metals tested and the combined effects of electrolytic solutions was compared to previous research. The analysis of radium in water was performed using a highly modified procedure which is included to specify the exact steps of the analytical method followed. This method has introduced innovations in equipment, technique, and the use of reagents. Results of a comparison of MnO 2 fiber to commercial water treatment media for the removal of cobalt and cesium is presented

  6. Zinc and nickel removal in limestone based treatment of acid mine drainage: The relative role of adsorption and co-precipitation

    International Nuclear Information System (INIS)

    Miller, Andrew; Wildeman, Thomas; Figueroa, Linda

    2013-01-01

    Highlights: • Limestone treatment of mining impacted water was simulated in batch reactors. • Zinc and nickel removals were quantified/characterized with a sequential extraction. • Removals were described with a surface complexation and a surface precipitation model. • Extraction/modeling results imply mechanisms beyond adsorption dominate metal removal. - Abstract: Mining influenced water may contain high metal and sulfate loads, and have low pH (acid mine drainage). Removal of these metals prior to environmental discharge is critical to maintain ecosystem vitality. Limestone based passive treatment systems are commonly used for pH neutralization. The same conditions that lead to pH neutralization may also remove a substantial amount of metals from solution, but the connection between treatment conditions and metal removal are not well understood. In this study, zinc and nickel removals are quantified in batch reactor simulated limestone treatment of acid mine drainage. The resulting solid phase is characterized with a sequential extraction procedure, and the removals are interpreted using surface complexation and surface precipitation models. Zinc and nickel removals are closely linked to the initial iron concentration in the mine water, but are also affected by pH, alkalinity, calcium and sulfate concentrations. The surface complexation model was based on literature descriptions of hydrous ferric oxide. In order to obtain a sufficient fit to the data, the surface site density was increased to an unrealistically high value. Uptake data was also fit to an existing surface precipitation model. The values used are similar to those found in previous studies. Both models indicate that adsorption is not the dominant removal process in the treatment system. Using adsorption only models will generally underpredict metal removals within limestone based treatment systems

  7. Removal of benzene under acidic conditions in a controlled Trickle Bed Air Biofilter.

    Science.gov (United States)

    Hassan, Ashraf Aly; Sorial, George A

    2010-12-15

    Trickle Bed Air Biofilters (TBABs) are considered to be economical and environmental-friendly for treatment of Volatile Organic Compounds (VOCs). Hydrophilic VOCs are easily degradable while hydrophobic ones pose a great challenge for adequate treatment due to the transfer of the VOC to the liquid phase. In this study the utilization of acidic pH is proposed for the treatment of benzene vapors. The acidic pH would encourage the growth of fungi as the main consortium. A TBAB operated at pH 4 was used for the treatment of an air stream contaminated with benzene under different loading rates ranging from 37 to 76.8 g/(m(3)h). The purpose of introducing fungi was to compare the performance with traditional TBAB operating under neutral pH in order to assess the biodegradation of benzene in mixtures with other compounds favoring acidic conditions. The experimental plan was designed to assess long-term performance with emphasis based on different benzene loading rates, removal efficiency with TBAB depth, and carbon mass balance closure. At benzene loading rate of 64 g/(m(3)h), the removal efficiency was 90%. At the maximum loading rate of 77 g/(m(3)h), the removal efficiency was 75% marking the maximum elimination capacity for the TBAB at 58.8 g/(m(3)h). Operating at acidic pH successfully supported the degradation of benzene in TBAB. It is worthwhile to note that benzene appears in mixtures with n-hexane and toluene, which are reported to be better degraded under such conditions. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Study of novel mechano-chemical activation process of red mud to optimize nitrate removal from water.

    Science.gov (United States)

    Alighardashi, A; Gharibi, H R; Raygan, Sh; Akbarzadeh, A

    2016-01-01

    Red mud (RM) is the industrial waste of alumina production and causes serious environmental risks. In this paper, a novel activation procedure for RM (mechano-chemical processing) is proposed in order to improve the nitrate adsorption from water. High-energy milling and acidification were selected as mechanical and chemical activation methods, respectively. Synthesized samples of adsorbent were produced considering two parameters of activation: acid concentrations and acidification time in two selected milling times. Optimization of the activation process was based on nitrate removal from a stock solution. Experimental data were analyzed with two-way analysis of variance and Kruskal-Wallis methods to verify and discover the accuracy and probable errors. Best conditions (acceptable removal percentage > 75) were 17.6% w/w for acid concentrate and 19.9 minutes for acidification time in 8 hours for milling time. A direct relationship between increase in nitrate removal and increasing the acid concentration and acidification time was observed. The adsorption isotherms were studied and compared with other nitrate adsorbents. Characterization tests (X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectrophotometry, dynamic light scattering, surface area analysis and scanning electron microscopy) were conducted for both raw and activated adsorbents. Results showed noticeable superiority in characteristics after activation: higher specific area and porosity, lower particle size and lower agglomeration in structure.

  9. Nitrogen removal on recycling water process of wastewater treatment plant effluent using subsurface horizontal wetland with continuous feed

    Science.gov (United States)

    Tazkiaturrizki, T.; Soewondo, P.; Handajani, M.

    2018-01-01

    Recycling water is a generic term for water reclamation and reuse to solve the scarcity of water. Constructed wetlands have been recognized as providing many benefits for wastewater treatment including water supply and control by recycling water. This research aims to find the best condition to significantly remove nitrogen using constructed wetland for recycling water of Bojongsoang Waste Water Treatment Plan (WWTP) effluent. Using media of soil, sand, gravel, and vegetation (Typha latifolia and Scirpus grossus) with an aeration system, BOD and COD parameters have been remarkably reduced. On the contrary, the removal efficiency for nitrogen is only between 50-60%. Modifications were then conducted by three step of treatment, i.e., Step I is to remove BOD/COD using Typha latifolia with an aeration system, Step II is todecrease nitrogen using Scirpus grossus with/without aeration, and Step III isto complete the nitrogen removal with denitrification process by Glycine max without aeration. Results of the research show that the nitrogen removal has been successfully increased to a high efficiency between 80-99%. The combination of aeration system and vegetation greatly affects the nitrogen removal. The vegetation acts as the organic nitrogen consumer (plant uptake) for amino acids, nitrate, and ammonium as nutrition, as well as theoxygen supplier to the roots so that aerobic microsites are formed for ammonification microorganisms.

  10. Removal of radium from drinking water

    International Nuclear Information System (INIS)

    Lauch, R.P.

    1992-08-01

    The report summarizes processes for removal of radium from drinking water. Ion exchange, including strong acid and weak acid resin, is discussed. Both processes remove better than 95 percent of the radium from the water. Weak acid ion exchange does not add sodium to the water. Calcium cation exchange removes radium and can be used when hardness removal is not necessary. Iron removal processes are discussed in relation to radium removal. Iron oxides remove much less than 20 percent of the radium from water under typical conditions. Manganese dioxide removes radium from water when competition for sorption sites and clogging of sites is reduced. Filter sand that is rinsed daily with dilute acid will remove radium from water. Manganese dioxide coated filter sorption removes radium but more capacity would be desirable. The radium selective complexer selectively removes radium with significant capacity if iron fouling is eliminated

  11. Study on removal of elemental mercury from simulated flue gas over activated coke treated by acid

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jinfeng [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Li, Caiting, E-mail: ctli@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Zhao, Lingkui; Zhang, Jie; Song, Jingke; Zeng, Guangming; Zhang, Xunan; Xie, Yine [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China)

    2015-02-28

    Highlights: • HClO{sub 4} treated AC was developed for effective Hg{sup 0} removal from simulated flue gas. • The exceptional effect of SO{sub 2} on Hg{sup 0} removal by AC{sub 4.5} was discussed. • Possible reaction mechanism of Hg{sup 0} removal over AC{sub 4.5} was put forward. - Abstract: This work addressed the investigation of activated coke (AC) treated by acids. Effects of AC samples, modified by ether different acids (H{sub 2}SO{sub 4}, HNO{sub 3} and HClO{sub 4}) or HClO{sub 4} of varied concentrations, on Hg{sup 0} removal were studied under simulated flue gas conditions. In addition, effects of reaction temperature and individual flue gas components including O{sub 2}, NO, SO{sub 2} and H{sub 2}O were discussed. In the experiments, Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were applied to explore the surface properties of sorbents and possible mechanism of Hg{sup 0} oxidation. Results showed that AC sample treated by HClO{sub 4} of 4.5 mol/L exhibited maximum promotion of efficiency on Hg{sup 0} removal at 160 °C. NO was proved to be positive in the removal of Hg{sup 0}. And SO{sub 2} displayed varied impact in capturing Hg{sup 0} due to the integrated reactions between SO{sub 2} and modified AC. The addition of O{sub 2} could improve the advancement further to some extent. Besides, the Hg{sup 0} removal capacity had a slight declination when H{sub 2}O was added in gas flow. Based on the analysis of XPS and FTIR, the selected sample absorbed Hg{sup 0} mostly in chemical way. The reaction mechanism, deduced from results of characterization and performance of AC samples, indicated that Hg{sup 0} could firstly be absorbed on sorbent and then react with oxygen-containing (C−O) or chlorine-containing groups (C−Cl) on the surface of sorbent. And the products were mainly in forms of mercuric chloride (HgCl{sub 2}) and mercuric oxide (HgO)

  12. An intensified esterification process of palm oil fatty acid distillate catalyzed by delipidated rice bran lipase.

    Science.gov (United States)

    Chong, Fui Chin; Tey, Beng Ti; Dom, Zanariah Mohd; Ibrahim, Nordin; Rahman, Russly Abd; Ling, Tau Chuan

    2006-09-07

    An intensified esterification process was operated by circulating 10 l of reaction mixtures, consisting of palm oil fatty acid distillate (PFAD) and glycerol in hexane, through a packed-bed reactor (PBR) filled with 10 kg of delipidated rice bran lipase (RBL). The influence of the process parameters, such as reaction temperature and type of water-removal agent, on the performance of this intensified esterification process were investigated. The highest degree of esterification (61%) was achieved at a reaction temperature of 65 masculineC, using silica gels as the water-removal agent. Thin-layer chromatography (TLC) analysis showed that the major composition of the esterified product was diacylglycerol.

  13. Removal of CdTe in acidic media by magnetic ion-exchange resin: A potential recycling methodology for cadmium telluride photovoltaic waste

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Teng, E-mail: zhangteng@mail.iee.ac.cn; Dong, Zebin; Qu, Fei; Ding, Fazhu; Peng, Xingyu; Wang, Hongyan; Gu, Hongwei

    2014-08-30

    Highlights: • Sulfonated magnetic microsphere was prepared as one strong acid cation-exchange resin. • Cd and Te can be removed directly from the highly acidic leaching solution of CdTe. • Good chemical stability, fast adsorbing rate and quick magnetic separation in strong acidic media. • A potential path for recycling CdTe photovoltaic waste. - Abstract: Sulfonated magnetic microspheres (PSt-DVB-SNa MPs) have been successfully prepared as adsorbents via an aqueous suspension polymerization of styrene-divinylbenzene and a sulfonation reaction successively. The resulting adsorbents were confirmed by means of Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS) and vibrating sample magnetometer (VSM). The leaching process of CdTe was optimized, and the removal efficiency of Cd and Te from the leaching solution was investigated. The adsorbents could directly remove all cations of Cd and Te from a highly acidic leaching solution of CdTe. The adsorption process for Cd and Te reached equilibrium in a few minutes and this process highly depended on the dosage of adsorbents and the affinity of sulfonate groups with cations. Because of its good adsorption capacity in strong acidic media, high adsorbing rate, and efficient magnetic separation from the solution, PSt-DVB-SNa MPs is expected to be an ideal material for the recycling of CdTe photovoltaic waste.

  14. Modelling of fluoride removal via batch monopolar electrocoagulation process using aluminium electrodes

    Science.gov (United States)

    Amri, N.; Hashim, M. I.; Ismail, N.; Rohman, F. S.; Bashah, N. A. A.

    2017-09-01

    Electrocoagulation (EC) is a promising technology that extensively used to remove fluoride ions efficiently from industrial wastewater. However, it has received very little consideration and understanding on mechanism and factors that affecting the fluoride removal process. In order to determine the efficiency of fluoride removal in EC process, the effect of operating parameters such as voltage and electrolysis time were investigated in this study. A batch experiment with monopolar aluminium electrodes was conducted to identify the model of fluoride removal using empirical model equation. The EC process was investigated using several parameters which include voltage (3 - 12 V) and electrolysis time (0 - 60 minutes) at a constant initial fluoride concentration of 25 mg/L. The result shows that the fluoride removal efficiency increased steadily with increasing voltage and electrolysis time. The best fluoride removal efficiency was obtained with 94.8 % removal at 25 mg/L initial fluoride concentration, voltage of 12 V and 60 minutes electrolysis time. The results indicated that the rate constant, k and number of order, n decreased as the voltage increased. The rate of fluoride removal model was developed based on the empirical model equation using the correlation of k and n. Overall, the result showed that EC process can be considered as a potential alternative technology for fluoride removal in wastewater.

  15. Aspartic Acid Protease from Botrytis cinerea Removes Haze-Forming Proteins during White Winemaking

    NARCIS (Netherlands)

    Sluyter, Van S.C.; Warnock, N.I.; Schmidt, S.; Anderson, P.; Kan, van J.A.L.; Bacic, A.; Waters, E.J.

    2013-01-01

    White wines suffer from heat-induced protein hazes during transport and storage unless the proteins are removed prior to bottling. Bentonite fining is by far the most commonly used method, but it is inefficient and creates several other process challenges. An alternative to bentonite is the

  16. Complete sulphate removal from neutralised acidic mine drainage with barium carbonate

    CSIR Research Space (South Africa)

    Swanepoel, H

    2012-03-01

    Full Text Available -barium-calcium) Desalination process which uses barium salts to further reduce the sulphate concentration to acceptable levels with the added advantage that sulphate removal can be controlled due to the low solubility of BaSO4. This paper reports on the results...

  17. Process for recovering a uranium containing concentrate and purified phosphoric acid from a wet process phosphoric acid containing uranium

    International Nuclear Information System (INIS)

    Weterings, C.A.M.; Janssen, J.A.

    1985-01-01

    A process is claimed for recovering from a wet process phosphoric acid which contains uranium, a uranium containing concentrate and a purified phosphoric acid. The wet process phosphoric acid is treated with a precipitant in the presence of a reducing agent and an aliphatic ketone

  18. Process for recovering a uranium containing concentrate and purified phosphoric acid from a wet process phosphoric acid containing uranium

    Energy Technology Data Exchange (ETDEWEB)

    Weterings, C.A.M.; Janssen, J.A.

    1985-04-30

    A process is claimed for recovering from a wet process phosphoric acid which contains uranium, a uranium containing concentrate and a purified phosphoric acid. The wet process phosphoric acid is treated with a precipitant in the presence of a reducing agent and an aliphatic ketone.

  19. Uranium recovery and uranium remove from acid mine waters by ion exchange resin; Remocao e recuperacao de uranio de aguas acidas de mina com resina de troca ionica

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Marcos R.L. [Comissao Nacional de Energia Nuclear (CNEN), Pocos de Caldas, MG (Brazil). Coordenacao do Laborarorio; Fatibello Filho, Orlando [Sao Carlos Univ., SP (Brazil). Dept. de Quimica

    1999-11-01

    Ion exchange using resins is one of few processes capable of reducing contaminants in effluents to very low levels according to environmental legislation. In this study the process was used to remove and recovery uranium from acid mine waters at Pocos de Caldas-MG Uranium Mining and Milling Plant. The presence of pyrite in the waste rock piles, resulting acid drainage with several pollutants. Including uranium ranging from 6 to 14 mg/l, as sulfate complex, that can be removed by an anionic exchanger. Studies of uranium sorption without treatment, and with lime pretreatment of water to precipitate the iron and recovery uranium as commercial product, are presented. Uranium elution was done with NaCl solutions. Saline concentration and retention time were the parameters studied. the uranium decontaminations level in the effluents from acid mine water was 94%. (author) 10 refs., 6 tabs., 3 figs.

  20. Removal of Acid Red 18 dye from Aqueous Solutions Using Nanoscale Zero-Valent Iron

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Yari

    2015-08-01

    Full Text Available Background and Purpose:Organic dyes with a complex structure are often toxic, carcinogenic, mutagenic, non-biodegradation and stable in the environment and if released to the environment without treatment can endanger the environment and human health. The aim was to evaluate the performance nanoscalezero-valent iron (NZVI in the removal of dye acid red 18 (AR18 from aqueous solutions. Materials and Methods:This study was conducted at the laboratory scale. In this study, the removal efficiency of AR18 from a synthetic solution by NZVI was investigated. As well as the effect of solution pH, dye concentration, the concentration of NZVI and contact time in decolorization efficiency was investigated. Results:The results show that in pH = 3, contact time of 80 minutes, dye concentration of 25 mg/l and concentration of NZVI of 2 g/l, the removal efficiency was about 94%. Conclusion:According to the results of experiments, NZVI has high efficiency in removal of AR18 from aqueous solution.

  1. Effect of acid leaching conditions on impurity removal from silicon doped by magnesium

    Directory of Open Access Journals (Sweden)

    Stine Espelien

    2017-07-01

    Full Text Available The effect of magnesium addition into a commercial silicon and its leaching refining behavior is studied for producing solar grade silicon feedstock. Two different levels of Mg is added into a commercial silicon and the leaching of the produced alloys by 10% HCl solution at 60 ℃ for different durations is performed. It is shown that the microstructure of the alloy and in particular the distribution of eutectic phases is dependent on the amount of the added Mg. Moreover, the metallic impurities in silicon such as Fe, Al, Ca and Ti are mainly forming silicide particles with different compositions. These silicides are physically more detached from the primary silicon grains and their removal through chemical and physical separation in leaching is better for higher Mg additions. It is observed that the leaching is more effective for the purification of smaller silicon particles produced from each Mg-doped silicon alloy. It is shown that acid leaching by the applied method is effective to reach more than 70% of phosphorous removal. It is also shown that the purity of silicon is dependent on the total Mg removal and effectiveness of leaching on removing the Mg2Si phase.

  2. Comparison of acidic polymers for the removal of cobalt from water solutions by polymer assisted ultrafiltration

    Energy Technology Data Exchange (ETDEWEB)

    Dambies, Laurent, E-mail: chemjobs@netcourrir.com [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Jaworska, Agnieszka, E-mail: a.jaworska@ichtj.waw.pl [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland); Zakrzewska-Trznadel, Grazyna; Sartowska, Bozena [Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw (Poland)

    2010-06-15

    In this study, three sulfonated water-soluble polymers based on poly(vinyl alcohol) of different molecular weights (10,000, 50,000 and 100,000 Da) were prepared and tested against commercially available poly(acrylic acid) for the removal of cobalt using polymer assisted ultrafiltration. High rejection rates were obtained between pH 3 and 6 with sulfonated poly(vinyl alcohol) (PVA 10,000 and 50,000 Da) whereas poly(acrylic acid) (PAA) of similar molecular weights performed rather poorly in this pH range. Sulfonation improved significantly sorption capability of PVA. Sulfonated PVA 10,000 was the best complexing agent with rejection rate above 95% between pH 3 and 6. For unmodified PVA the rejection rate was only 30-45% at pH 6 and there was no rejection at pH 3 at all. PAA rejection rate was above 90% at pH 6 and only about 10% at pH 3. Large scale experiment in cross-flow, continuous apparatus conducted by using PVA-SO{sub 3}H 10,000 Da to remove {sup 60}Co radioisotope from water solutions showed excellent results demonstrating the potential of this polymer to purify acidic radioactive wastes containing cobalt radioisotopes.

  3. Evaluation of ethylenediaminetetraacetic acid (EDTA) solution and gel for smear layer removal.

    Science.gov (United States)

    Dotto, Sidney Ricardo; Travassos, Rosana Maria Coelho; de Oliveira, Elias Pandonor Motcy; Machado, Manoel Eduardo de Lima; Martins, José Luiz

    2007-08-01

    The purpose of this in vitro study was to compare the efficacy of 24% ethylenediaminetetraacetic acid (EDTA) gel and 17% EDTA solution in cleaning dentine walls after root canal instrumentation. Thirty human canine teeth were divided into three groups of 10 teeth each. In Group 1, 1% sodium hypochlorite was used as the irrigating solution; in Group 2, 1% sodium hypochlorite was used with 17% EDTA solution; and in Group 3, 1% sodium hypochlorite was used with 24% EDTA gel. The presence of a smear layer was analysed after instrumentation using scanning electron microscopy. The Kruskal-Wallis test revealed a statistical difference (P 0.05). The results indicate that 1% sodium hypochlorite alone does not remove the smear layer and that there was no statistical difference between EDTA gel and EDTA solution in smear layer removal.

  4. Sequential study on reactive blue 29 dye removal from aqueous solution by peroxy acid and single wall carbon nanotubes: experiment and theory

    Directory of Open Access Journals (Sweden)

    Jahangiri-Rad Mahsa

    2013-01-01

    Full Text Available Abstract The majority of anthraquinone dye released to the environment come from antrapogenic sources. Several techniques are available for dyes' removal. In this study removal of reactive blue 29 (RB29 by an advanced oxidation process sequenced with single wall carbon nanotubes was investigated. Advanced oxidation process was optimized over a period of 60 minutes by changing the ratio of acetic acid to hydrogen peroxide, the compounds which form peroxy acid. Reduction of 20.2% -56.4% of reactive blue 29 was observed when the ratio of hydrogen peroxide/acetic acid/dye changed from 344/344/1 to 344/344/0.08 at different times (60, 120 and 180 min. The optimum ratio of acetic acid/hydrogen peroxide/dye was found to be 344/344/0.16 over 60 min. The resultant then was introduced for further removal by single wall carbon nanotubes(SWCNTs as adsorbent. The adsorption of reactive blue 29 onto SWCNTs was also investigated. Langmuir, Freundlich and BET isotherms were determined and the results revealed that the adsorption of RB29 onto SWCNTs was well explained by BET model and changed to Freundlich isotherm when SWCNTs was used after the application of peroxy acid. Kinetic study showed that the equilibrium time for adsorption of RB 29 on to SWCNT is 4 h. Experiments were carried out to investigate adsorption kinetics, adsorbent capacity and the effect of solution pH on the removal of reactive blue29. The pseudo-second order kinetic equation could best describe the sorption kinetics. The most efficient pH for color removal (amongst pH=3, 5 and 8 was pH= 5. Further studies are needed to identify the peroxy acid degradation intermediates and to investigate their effects on SWCNTs.

  5. FY13 GLYCOLIC-NITRIC ACID FLOWSHEET DEMONSTRATIONS OF THE DWPF CHEMICAL PROCESS CELL WITH SIMULANTS

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.; Zamecnik, J.; Best, D.

    2014-03-13

    Savannah River Remediation is evaluating changes to its current Defense Waste Processing Facility flowsheet to replace formic acid with glycolic acid in order to improve processing cycle times and decrease by approximately 100x the production of hydrogen, a potentially flammable gas. Higher throughput is needed in the Chemical Processing Cell since the installation of the bubblers into the melter has increased melt rate. Due to the significant maintenance required for the safety significant gas chromatographs and the potential for production of flammable quantities of hydrogen, eliminating the use of formic acid is highly desirable. Previous testing at the Savannah River National Laboratory has shown that replacing formic acid with glycolic acid allows the reduction and removal of mercury without significant catalytic hydrogen generation. Five back-to-back Sludge Receipt and Adjustment Tank (SRAT) cycles and four back-to-back Slurry Mix Evaporator (SME) cycles were successful in demonstrating the viability of the nitric/glycolic acid flowsheet. The testing was completed in FY13 to determine the impact of process heels (approximately 25% of the material is left behind after transfers). In addition, back-to-back experiments might identify longer-term processing problems. The testing was designed to be prototypic by including sludge simulant, Actinide Removal Product simulant, nitric acid, glycolic acid, and Strip Effluent simulant containing Next Generation Solvent in the SRAT processing and SRAT product simulant, decontamination frit slurry, and process frit slurry in the SME processing. A heel was produced in the first cycle and each subsequent cycle utilized the remaining heel from the previous cycle. Lower SRAT purges were utilized due to the low hydrogen generation. Design basis addition rates and boilup rates were used so the processing time was shorter than current processing rates.

  6. Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xin [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Jin, Pengkang, E-mail: pkjin@hotmail.com [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Hou, Rui [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Yang, Lei [Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800 (Australia); Wang, Xiaochang C., E-mail: xcwang@xauat.edu.cn [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China)

    2017-04-05

    Highlights: • A novel HOC process was firstly put forward to apply in wastewater reclamation. • Interactions between ozone and Al-based coagulants was found in the HOC process. • Ozonation can be catalyzed and enhanced by Al-based coagulants in the HOC process. • HOC process showed better organics removal than pre-ozonation-coagulation process. - Abstract: A novel hybrid ozonation-coagulation (HOC) process was developed for application in wastewater reclamation. In this process, ozonation and coagulation occurred simultaneously within a single unit. Compared with the conventional pre-ozonation-coagulation process, the HOC process exhibited much better performance in removing dissolved organic matters. In particular, the maximal organic matters removal efficiency was obtained at the ozone dosage of 1 mgO{sub 3}/mg DOC at each pH value (pH 5, 7 and 9). In order to interpret the mechanism of the HOC process, ozone decomposition was monitored. The results indicated that ozone decomposed much faster in the HOC process. Moreover, by using the reagent of O{sub 3}-resistant hydroxyl radical (·OH) probe compound, para-chlorobenzoic acid (pCBA), and electron paramagnetic resonance (EPR) analysis, it was observed that the HOC process generated higher content of ·OH compared with pre-ozonation process. This indicates that the ·OH oxidation reaction as the key step can be catalyzed and enhanced by Al-based coagulants and their hydrolyzed products in this developed process. Thus, based on the catalytic effects of Al-based coagulants on ozonation, the HOC process provides a promising alternative to the conventional technology for wastewater reclamation in terms of higher efficiency.

  7. Copper removal from acid mine drainage-polluted water using glutaraldehyde-polyethyleneimine modified diatomaceous earth particles

    Directory of Open Access Journals (Sweden)

    Mikael Larsson

    2018-02-01

    Full Text Available Mine waters and tailings generated from mining and mineral processing activities often have detrimental impact on the local environment. One example is acid mine drainage, in which sulphides in the mining waste react with water and oxygen to produce an acidic environment that subsequently dissolves host rock minerals from the waste containing toxic metals and trace elements. Copper is one such metal of significance, as it is mined at large volumes in sulphide containing ores. It has strong biocidal activity that greatly affects ecosystems. We have previously reported that glutaraldehyde (GA-crosslinked polyethyleneimine (PEI has strong affinity and selectivity for copper and that diatomaceous earth (DE particles can be modified with the material to form a copper-extraction resin. In this study, the copper uptake of GA-PEI-DE particles was investigated from synthetic and real acid mine drainage samples under different pHs and their copper removal performance was compared with that of selected commercial resins. The results revealed that copper could effectively and preferentially bind to the material at pH 4, and that the copper could be completely eluted by lowering of the pH. In addition, effective copper uptake and elution was demonstrated using real legacy acid mine drainage water from Mount Lyell in Tasmania.

  8. Removal of Humic Substances from Water by Advanced Oxidation Process Using UV/TiO2 Photo Catalytic Technology

    Directory of Open Access Journals (Sweden)

    Hassan Khorsandi

    2009-01-01

    Full Text Available Humic substances have been known as precursors to disinfection by-products. Because conventional treatment processes cannot meet disinfection by-product standards, novel methods have been increasingly applied for the removal of disinfection by-products precursors. The UV/TiO2 process is one of the advanced oxidation processes using the photocatalytic technology. The most important advantages of this process are its stability and high efficiency removal. The present study aims to investigate the effect of UV/TiO2 photo-catalytic technology on removal of humic substances. The study was conducted in a lab-scale batch photo-catalytic reactor using the interval experimental method. The UV irradiation source was a low pressure mercury vapor lamp 55w that was axially centered and was immersed in a humic acids solution within a stainless steel tubular 2.8 L reaction volume. Each of the samples taken from the UV/TiO2 process and other processes studied were analyzed for their dissolved organic carbon, UV absorbance at 254nm, and specific UV254 absorbance. The results indicated the high efficiency of the UV/TiO2 photo-catalytic process (TiO2=0.1 g/L and pH=5, compared to other processes, for humic substances removal from water sources. The process was also found to be capable of decreasing the initial dissolved organic carbon from 5 to 0.394 mg/L. The Specific UV254 Absorbance of 2.79 L/mg.m was attained after 1.5 hr. under photo-catalytic first order reaction (k= 0.0267 min-1. It may be concluded that the UV/TiO2 process can provide desirable drinking water quality in terms of humic substance content.

  9. Applicability of MIEX(®)DOC process for organics removal from NOM laden water.

    Science.gov (United States)

    Karpinska, Anna M; Boaventura, Rui A R; Vilar, Vítor J P; Bilyk, Andrzej; Molczan, Marek

    2013-06-01

    The aim of this study was to evaluate applicability of ion exchange process for organics removal from Douro River surface water at the intake of Lever water treatment plant using magnetized ion exchange resin MIEX®. Qualitative analysis of the natural organic matter present in the surface water and prediction of its amenability to removal in conventional coagulation process were assessed. Results obtained in MIEX®DOC process kinetic batch experiments allowed determination of ion exchange efficiency in dissolved organic carbon (DOC), UV absorbing organics, and true color removal. The data were compared with the efficiencies of the conventional unit processes for organics removal at Lever WTP. MIEX®DOC process revealed to be more efficient in DOC removal than conventional treatment achieving the efficiencies in the range of 61-91 %, lowering disinfection by-products formation potential of the water. DOC removal efficiency at Lever WTP depends largely on the raw water quality and ranges from 28 % for water of moderated quality to 89 % of significantly deteriorated quality. In this work, MIEX®DOC process was also used as a reference method for the determination of contribution of anionic fraction to dissolved organic matter and selectivity of the unit processes at Lever WTP for its removal.

  10. Zinc removal from wastewater by complexation-microfiltration process

    Directory of Open Access Journals (Sweden)

    Trivunac Katarina

    2012-01-01

    Full Text Available As a result of its wide industrial applications, zinc has become an important contaminant in aquatic environment since it is a toxic heavy metal and some of its compounds such as zinc arsenate and zinc cyanide, may be extremely hazardous. Therefore, there is a growing need for developing simple methods capable of separating and recovering trace zinc from environmental waters. Nowadays, the ultra and microfiltration method for trace metals removal from waters by the addition of water-soluble polymers into the aqueous solutions has become a significant research area. The choice of watersoluble macroligands remains important for developing this technology. Sodium carboxymethyl cellulose (Na-CMC was selected as complexing agent. The microfiltration experiments were carried out in stirred dead-end cell. To separate formed polymer-metal complex Versapor membranes were used. The concentration of heavy metal ions after microfiltration in aqueous solution was determined using atomic absorption spectroscopy (AAS. Effects of amount of complexing agent, pH value, type of anion, ionic strength and operating pressure on the flux (J and rejection coefficient (R were investigated. Experimental results indicate a considerable influence of the pH, ionic strength and type of anion on the rejection coefficient, while effect of amount of complexing agent is relatively insignificant. The Na-CMC used in the research proved to be very effective, which may be supported by the high rejection coefficients obtained (99%.

  11. Relationships between removal processes and residence times for atmospheric pollutants

    International Nuclear Information System (INIS)

    Slinn, W.G.N.

    1978-01-01

    This report is concerned with improving estimates for the residence times of atmospheric trace constituents in various atmospheric reservoirs. Residence times are defined only for steady-state conditions; i.e., when the net growth rate vanishes. The most useful case of vanishing net growth rate is when the total growth rate is equal to the decay rate. It is demonstrated that the most important advance towards improving estimates of pollutant residence times is through proper choices of reservoirs. Chosen reservoirs should possess the following features: steady-state conditions, uniform mixing ratio throughout or throughout specified subreservoirs, and subreservoirs chosen in which removal rates can be treated as approximate constants. An example of a poorly mixed reservoir, the stratosphere, is discussed. In another example, it is suggested that commonly used reservoirs for atmospheric CO 2 have been chosen poorly and that a substantial portion of the anthropogenic CO 2 released during the past 50 years may still be mixing into the stratosphere. In another example, it is suggested that determination of the dry deposition velocity for accumulation-mode aerosol particles may not be so important as previously thought. To improve estimates for the atmospheric residence times of these particles, it is important to increase knowledge of what is called the ascension velocity

  12. Accelerated hydrocarbon removal with the NoVOCs trademark process

    International Nuclear Information System (INIS)

    Dawson, G.W.; McKeon, T.J.

    1996-01-01

    It has been estimated that by 1990, there were over 240,000 leaking underground storage tanks in the US and that the majority of those tanks had contained some type of petroleum fuel. The resulting hydrocarbon contamination from those leaking tanks became the focus of a significant amount of environmental restoration effort. Free product was collected and removed from the water table. Contaminated soils were excavated for thermal desorption or land farming, or aerated in place to promote bioremediation. Affected ground water was withdrawn by means of extraction wells and routed to air stripping towers or, more recently, stripped in place with in situ air sparging. NoVOCs trademark is a patented design for the application of in-well stripping as an alternative to pump and treat systems over which it offers two unique advantages: (1) Development of a circulation pattern within the saturated zone that optimizes dissolution and transport of contaminants to the well; and (2) Separation of the volatile contaminants for the ground water in the well so that only vapor is transported above ground and there are no water discharges to be managed

  13. Thermal control system. [removing waste heat from industrial process spacecraft

    Science.gov (United States)

    Hewitt, D. R. (Inventor)

    1983-01-01

    The temperature of an exothermic process plant carried aboard an Earth orbiting spacecraft is regulated using a number of curved radiator panels accurately positioned in a circular arrangement to form an open receptacle. A module containing the process is insertable into the receptacle. Heat exchangers having broad exterior surfaces extending axially above the circumference of the module fit within arcuate spacings between adjacent radiator panels. Banks of variable conductance heat pipes partially embedded within and thermally coupled to the radiator panels extend across the spacings and are thermally coupled to broad exterior surfaces of the heat exchangers by flanges. Temperature sensors monitor the temperature of process fluid flowing from the module through the heat exchanges. Thermal conduction between the heat exchangers and the radiator panels is regulated by heating a control fluid within the heat pipes to vary the effective thermal length of the heat pipes in inverse proportion to changes in the temperature of the process fluid.

  14. Removal of Dye (Blue 56 From Aqueous Solution via Adsorption onto Pistachio Shell: kinetic and isotherm study of removal process

    Directory of Open Access Journals (Sweden)

    A. Ravanpaykar

    2012-03-01

    Full Text Available In the present investigation, shells of pistachio are used as adsorbents and they have been successfully used for the removal of Blue 56, from water samples. The effect of various parameters such as: pH, amounts of adsorbents, size of adsorbent particles and contact time on removal processing were investigated. Inthisstudy Freundlichabsorptionisotherms and Langmuir were investigated. The experimental data were correlated reasonably well by the Freundlich adsorption isotherm and isotherm parameters were calculated. In order to investigate the efficiency of Blue 56 adsorption on the pistachio shell, pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion kinetic models were studied. Themodel that hadgoodcorrelationtoattractFreundlichwas chosenasthemodel. Its kineticsfollowsthepseudosecond order reaction.

  15. Efficiency of a Photoreactor Packed with Immobilized Titanium Dioxide Nanoparticles in the Removal of Acid Orange 7.

    Science.gov (United States)

    Sheidaei, Behnaz; Behnajady, Mohammad A

    2016-05-01

    In this paper, the removal efficiency of Color Index Acid Orange 7 (AO7) as a model contaminant was investigated in a batch-recirculated photoreactor packed with immobilized titanium dioxide type P25 nanoparticles on glass beads. The effects of different operational parameters such as the initial concentration of AO7, the volume of solution, the volumetric flowrate, and the light source power in the photoreactor were investigated. The results indicate that the removal percent increased with the rise in volumetric flowrate and power of the light source, but decreased with the rise of the initial concentration of AO7 and the volume of solution. The AO7 degradation was followed through total organic carbon, gas chromatography/mass spectroscopy (GC/MS), and mineralization products analysis. The ammonium and sulfate ions were analyzed as mineralization products of nitrogen and sulfur heteroatoms, respectively. The results of GC/MS revealed the production of 1-indanone, 1-phthalanone, and 2-naphthalenol as intermediate products for the removal of AO7 in this process.

  16. Removal of hexavalent chromium upon interaction with biochar under acidic conditions: mechanistic insights and application.

    Science.gov (United States)

    Choudhary, Bharat; Paul, Debajyoti; Singh, Abhas; Gupta, Tarun

    2017-07-01

    Chromium pollution of soil and water is a serious environmental concern due to potential carcinogenicity of hexavalent chromium [Cr(VI)] when ingested. Eucalyptus bark biochar (EBB), a carbonaceous black porous material obtained by pyrolysis of biomass at 500 °C under oxygen-free atmosphere, was used to investigate the removal of aqueous Cr(VI) upon interaction with the EBB, the dominant Cr(VI) removal mechanism(s), and the applicability to treat Cr(VI)-contaminated wastewater. Batch experiments showed complete removal of aqueous Cr(VI) at pH 1-2; sorption was negligible at pH 1, but ~55% of total Cr was sorbed onto the EBB surface at pH 2. Detailed investigations on unreacted and reacted EBB through Fourier transform infrared spectroscopy and X-ray photoelectron spectrometry (XPS) indicate that the carboxylic groups in biochar played a dominant role in Cr(VI) sorption, whereas the phenolic groups were responsible for Cr(VI) reduction. The predominance of sorption-reduction mechanism was confirmed by XPS studies that indicated ~82% as Cr(III) and ~18% as Cr(VI) sorbed on the EBB surface. Significantly, Cr(VI) reduction was also facilitated by dissolved organic matter (DOM) extracted from biochar. This reduction was enhanced by the presence of biochar. Overall, the removal of Cr(VI) in the presence of biochar was affected by sorption due to electrostatic attraction, sorption-reduction mediated by surface organic complexes, and aqueous reduction by DOM. Relative dominance of the aqueous reduction mechanism depended on a critical biochar dosage for a given electrolyte pH and initial Cr(VI) concentration. The low-cost EBB developed here successfully removed all Cr(VI) in chrome tanning acidic wastewater and Cr(VI)-contaminated groundwater after pH adjustment, highlighting its potential applicability in effective Cr(VI) remediation.

  17. 2-Chlorophenol Removal of Aqueous Solution Using Advanced Oxidation Processes Resulting from Iron/ Persulfate and Ultra Violet/ Persulfate

    Directory of Open Access Journals (Sweden)

    Shokufeh Astereki

    2016-06-01

    Full Text Available Background: Advanced oxidation processes are used to remove toxic aromatic compounds with low biodegradability, such as 2-chlorophenol. This study investigated the use of sulfate (SO4- and persulfate (S2O82- radicals, as one of the advanced oxidation methods, to remove 2- chlorophenol from aquatic solutions. Methods: This experimental and pilot-scale study was carried out using two chemical batch reactors; one of the reactors equipped with UV lamps and the other was on the hot plate. In iron/ persulfate (Fe/S2O82- and ultra violet/ persulfate (UV/S2O82- processes different parameters were investigated. Results: Iron, UV, the initial pH of the solution, persulfate concentration have considerable effects on the elimination of 2-chlorophenol in both processes. In both processes, the maximum elimination occurred in acidic conditions. The elimination efficiency was increased by increasing the concentration of 2-chlorophenol and UV intensity, and also by decreasing the concentration of persulfate and iron. Accordingly, in iron/ persulfate and ultra violet/ persulfate processes 2-chlorophenol was eliminated with 99.96% and 99.58% efficiencies, respectively. Conclusion: Sulfate radicals produced from activated persulfate ions with hot-Fe ion and UV radiation have significant impact on the removal of 2-chlorophenol. Therefore, the processes of Fe/S2O82- and UV/S2O82- can be regarded as good choices for industrial wastewater treatment plants operators in the future.

  18. Effect of synthetic iron colloids on the microbiological NH(4)(+) removal process during groundwater purification.

    Science.gov (United States)

    Wolthoorn, Anke; Temminghoff, Erwin J M; van Riemsdijk, Willem H

    2004-04-01

    Subsurface aeration is used to oxidise Fe in situ in groundwater that is used to make drinking water potable. In a groundwater system with pH>7 subsurface aeration results in non-mobile Fe precipitate and mobile Fe colloids. Since originally the goal of subsurface aeration is to remove iron in situ, the formation of non-mobile iron precipitate, which facilitates the metal's removal, is the desired result. In addition to this intended effect, subsurface aeration may also strongly enhance the microbiological removal of ammonium (NH(4)(+)) in the purification station. Mobile iron colloids could be the link between subsurface aeration and the positive effect on the NH(4)(+) removal process. Therefore, the objective of this study was to assess whether synthetic iron colloids could improve the NH(4)(+) removal process. The effect of synthetic iron colloids on the NH(4)(+) removal process was studied using an artificial purification set-up on a laboratory scale. Columns that purified groundwater with or without added synthetic iron colloids were set up in duplicate. The results showed that the NH(4)(+) removal was significantly ( alpha = 0.05 ) increased in columns treated with the synthetic iron colloids. Cumulative after 4 months about 10% more NH(4)(+) was nitrified in the columns that was treated with the groundwater containing synthetic iron colloids. The results support the hypothesis that mobile iron colloids could be the link between subsurface aeration and the positive effect on the NH(4)(+) removal process.

  19. Removing Background Noise with Phased Array Signal Processing

    Science.gov (United States)

    Podboy, Gary; Stephens, David

    2015-01-01

    Preliminary results are presented from a test conducted to determine how well microphone phased array processing software could pull an acoustic signal out of background noise. The array consisted of 24 microphones in an aerodynamic fairing designed to be mounted in-flow. The processing was conducted using Functional Beam forming software developed by Optinav combined with cross spectral matrix subtraction. The test was conducted in the free-jet of the Nozzle Acoustic Test Rig at NASA GRC. The background noise was produced by the interaction of the free-jet flow with the solid surfaces in the flow. The acoustic signals were produced by acoustic drivers. The results show that the phased array processing was able to pull the acoustic signal out of the background noise provided the signal was no more than 20 dB below the background noise level measured using a conventional single microphone equipped with an aerodynamic forebody.

  20. Modeling of a Large-Scale High Temperature Regenerative Sulfur Removal Process

    DEFF Research Database (Denmark)

    Konttinen, Jukka T.; Johnsson, Jan Erik

    1999-01-01

    model that does not account for bed hydrodynamics. The pilot-scale test run results, obtained in the test runs of the sulfur removal process with real coal gasifier gas, have been used for parameter estimation. The validity of the reactor model for commercial-scale design applications is discussed.......Regenerable mixed metal oxide sorbents are prime candidates for the removal of hydrogen sulfide from hot gasifier gas in the simplified integrated gasification combined cycle (IGCC) process. As part of the regenerative sulfur removal process development, reactor models are needed for scale......-up. Steady-state kinetic reactor models are needed for reactor sizing, and dynamic models can be used for process control design and operator training. The regenerative sulfur removal process to be studied in this paper consists of two side-by-side fluidized bed reactors operating at temperatures of 400...

  1. Treatment of wastes arising from decontamination process using citric acid as a decontaminate agent

    International Nuclear Information System (INIS)

    Mierzwa, J.C.; Riella, H.G.; Carvalho, E.U. de

    1993-01-01

    Wastes arising from equipment decontamination processes from nuclear fuel cycle facilities at Coordenacao de Projetos Especiais - Comissao Nacional de Energia Nuclear, Sao Paulo (COPESP-CNEN/SP) has been studied after using citric acid as a decontaminate agent. Precipitation of uranium and metallic impurities resulted from use of sodium hydroxide or calcium oxide plus a flocculation agent. The removal efficient of uranium was 95% and 99% for sodium hydroxide and calcium oxide respectively. The results shows that this process can be used to test wastes from decontamination processes which use citric acid. (B.C.A.). 03 refs, 08 figs, 04 tabs

  2. A bioseparation process for removing heavy metals from waste ...

    African Journals Online (AJOL)

    The role of cell structure, cell wall, micropores and macropores is evaluated in terms of the potential of these biosorbents for metal sequestration. Binding mechanisms are discussed, including the key functional groups involved and the ion-exchange process. Quantification of metal-biomass interactions is fundamental to the ...

  3. The water vapor nitrogen process for removing sodium from LMFBR components

    Energy Technology Data Exchange (ETDEWEB)

    Crippen, M D; Funk, C W; Lutton, J M [Hanford Engineering Development Laboratory, Richland (United States)

    1978-08-01

    Application and operation of the Water Vapor-Nitrogen Process for removing sodium from LMFBR components is reviewed. Emphasis is placed on recent efforts to verify the technological bases of the process, to refine the values of process parameters and to ensure the utility of the process for cleaning and requalifying components. (author)

  4. Using pyrolytic acid leaching as a pretreatment step in a biomass fast pyrolysis plant: process design and economic evaluation

    NARCIS (Netherlands)

    Oudenhoven, Stijn; van der Ham, Aloysius G.J.; van den Berg, Henderikus; Westerhof, Roel Johannes Maria; Kersten, Sascha R.A.

    2016-01-01

    Removing alkali and alkaline earth metals (AAEMs) from biomass, with pyrolytic acids, before pyrolysis leads to increased organic oil and sugar yields. These pyrolytic acids are produced and concentrated within the pyrolysis process itself. The purpose of this paper was to evaluate under which

  5. Effects of UV irradiation on humic acid removal by ozonation, Fenton and Fe0/air treatment: THMFP and biotoxicity evaluation

    International Nuclear Information System (INIS)

    Wei, Ming-Chi; Wang, Kai-sung; Hsiao, Tung-En; Lin, I.-Chen; Wu, Hui-Ju; Wu, Yuh-Luan; Liu, Pey-Horng; Chang, Shih-Hsien

    2011-01-01

    Highlights: → Fe 0 /air rapidly and effectively removed HA within 9 min and its COD, biotoxicity and THMFP were low. → THMFP of ozonation-treated solution was much higher than those of Fenton-treated and Fe 0 /air-treated solutions. → UV irradiation during ozonation and Fenton oxidation enhanced HA removal, but did not reduce the THMFP of the treated solutions. → Fe 0 /air treatment with UV irradiation obviously increased the THMFP of the treated solution. → The relationship between biotoxicity and chloroform in the chlorinated solution was insignificant. - Abstract: Effects of UV irradiation on humic acid (HA) removal by Fe 0 /air, ozonation and Fenton oxidation were investigated. The trihalomethane forming potential (THMFP) and toxicity of treated solutions were also evaluated. The experimental conditions were ozone of 21 mg min -1 , H 2 O 2 of 8 x 10 -4 M, Fe 0 of 20 g L -1 , air flow of 5 L min -1 , and UVC of 9 W. Results indicated that Fe 0 /air rapidly removed HA color (>99%) and COD (90%) within 9 min. 51-81% of color and 43-50% of COD were removed by ozonation and Fenton oxidation after 60 min. Both UV enhanced ozone and Fenton oxidation removed HA, but the Fe 0 /air process did not. Spectrum results showed all processes effectively diminished UV-vis spectra, except for ozonation. The THMFP of Fe 0 /air-treated solution (114 μg L -1 ) was much lower than those of Fenton- (226 μg L -1 ) and ozonation-treated solutions (499 μg L -1 ). Fe 0 /air with UV irradiation obviously increased the THMFP of treated solution (502 μg L -1 ). The toxicity results obtained from Vibrio fischeri light inhibition test indicated that the toxicity of Fe 0 /air-treated solution (5%) was much lower than that of ozonation- (33%) and Fenton-treated solutions (31%). Chlorination increased the solution toxicity. The correlation between biotoxicity and chloroform in the chlorinated solution was insignificant.

  6. Sono assisted electrocoagulation process for the removal of pollutant from pulp and paper industry effluent.

    Science.gov (United States)

    Asaithambi, P; Aziz, Abdul Raman Abdul; Sajjadi, Baharak; Daud, Wan Mohd Ashri Bin Wan

    2017-02-01

    In the present work, the efficiency of the sonication, electrocoagulation, and sono-electrocoagulation process for removal of pollutants from the industrial effluent of the pulp and paper industry was compared. The experimental results showed that the sono-electrocoagulation process yielded higher pollutant removal percentage compared to the sonication and electrocoagulation process alone. The effect of the operating parameters in the sono-electrocoagulation process such as electrolyte concentration (1-5 g/L), current density (1-5 A/dm 2 ), effluent pH (3-11), COD concentration (1500-6000 mg/L), inter-electrode distance (1-3 cm), and electrode combination (Fe and Al) on the color removal, COD removal, and power consumption were studied. The maximum color and COD removal percentages of 100 and 95 %, respectively, were obtained at the current density of 4 A/dm 2 , electrolyte concentration of 4 g/L, effluent pH of 7, COD concentration of 3000 mg/L, electrode combination of Fe/Fe, inter-electrode distance of 1 cm, and reaction time of 4 h, respectively. The color and COD removal percentages were analyzed by using an UV/Vis spectrophotometer and closed reflux method. The results showed that the sono-electrocoagulation process could be used as an efficient and environmental friendly technique for complete pollutant removal.

  7. Future CO2 removal from pulp mills - Process integration consequences

    International Nuclear Information System (INIS)

    Hektor, Erik; Berntsson, Thore

    2007-01-01

    Earlier work has shown that capturing the CO 2 from flue gases in the recovery boiler at a pulp mill can be a cost-effective way of reducing mill CO 2 emissions. However, the CO 2 capture cost is very dependent on the fuel price. In this paper, the potential for reducing the need for external fuel and thereby the possibility to reduce the cost for capturing the CO 2 are investigated. The reduction is achieved by using thermal process integration. In alternative 1, the mill processes are integrated and a steam surplus made available for CO 2 capture, but still there is a need for external fuel. In alternative 2, the integration is taken one step further, the reboiler is fed with MP steam, and the heat of absorption from the absorption unit is used for generation of LP steam needed at the mill. The avoidance costs are in both cases lower than before the process integration. The avoidance cost in alternative 1 varies between 25.4 and 30.7 EUR/tonne CO 2 depending on the energy market parameters. For alternative 2, the cost varies between 22.5 and 27.2 EUR/tonne CO 2 . With tough CO 2 reduction targets and correspondingly high CO 2 emission costs, the annual earnings can be substantial, 18.6 MEUR with alternative 1 and 21.2 MEUR with alternative 2

  8. Calcium and organic matter removal by carbonation process with waste incineration flue gas towards improvement of leachate biotreatment performance.

    Science.gov (United States)

    Zhang, Cheng; Zhu, Xuedong; Wu, Liang; Li, Qingtao; Liu, Jianyong; Qian, Guangren

    2017-09-01

    Municipal solid wastes incineration (MSWI) flue gas was employed as the carbon source for in-situ calcium removal from MSWI leachate. Calcium removal efficiency was 95-97% with pH of 10.0-11.0 over 100min of flue gas aeration, with both bound Ca and free Ca being removed effectively. The fluorescence intensity of tryptophan, protein-like and humic acid-like compounds increased after carbonation process. The decrease of bound Ca with the increase of precipitate indicated that calcium was mainly converted to calcium carbonate precipitate. It suggested that the interaction between dissolved organic matter and Ca 2+ was weakened. Moreover, 10-16% of chemical oxygen demand removal and the decrease of ultraviolet absorption at 254nm indicated that some organics, especially aromatic compound decreased via adsorption onto the surface of calcium carbonate. The results indicate that introduce of waste incineration flue gas could be a feasible way for calcium removal from leachate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Optimization of hexavalent chromium removal from aqueous solution using acid-modified granular activated carbon as adsorbent through response surface methodology

    International Nuclear Information System (INIS)

    Daoud, Waseem; Ebadi, Taghi; Fahimifar, Ahmad

    2015-01-01

    Response surface methodology (RSM) was applied to evaluate the effect of the main operational variables, including initial pH, initial chromium ion concentration, bulk density of GAC and time on the removal of hexavalent chromium Cr(Ⅵ) from contaminated groundwater by permeable reactive barriers (PRB) with acid-modified granular activated carbon (GAC) as an adsorbent material. The removal rates of Cr(Ⅵ) under different values of these parameters were investigated and results indicated high adsorption capacity at low pH and low initial metal ion concentration of Cr(Ⅵ), but the bulk density of GAC slightly influenced the process efficiency. According to the ANOVA (analysis of variance) results, the model presents high R 2 values of 94.35% for Cr(Ⅵ) removal efficiency, which indicates that the accuracy of the polynomial models was good. Also, quadratic regression models with estimated coefficients were developed to describe the pollutant removals

  10. Optimization of hexavalent chromium removal from aqueous solution using acid-modified granular activated carbon as adsorbent through response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Daoud, Waseem; Ebadi, Taghi; Fahimifar, Ahmad [Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of)

    2015-06-15

    Response surface methodology (RSM) was applied to evaluate the effect of the main operational variables, including initial pH, initial chromium ion concentration, bulk density of GAC and time on the removal of hexavalent chromium Cr(Ⅵ) from contaminated groundwater by permeable reactive barriers (PRB) with acid-modified granular activated carbon (GAC) as an adsorbent material. The removal rates of Cr(Ⅵ) under different values of these parameters were investigated and results indicated high adsorption capacity at low pH and low initial metal ion concentration of Cr(Ⅵ), but the bulk density of GAC slightly influenced the process efficiency. According to the ANOVA (analysis of variance) results, the model presents high R{sup 2} values of 94.35% for Cr(Ⅵ) removal efficiency, which indicates that the accuracy of the polynomial models was good. Also, quadratic regression models with estimated coefficients were developed to describe the pollutant removals.

  11. Kinetic Study on the Removal of Iron from Gold Mine Tailings by Citric Acid

    Science.gov (United States)

    Mashifana, T.; Mavimbela, N.; Sithole, N.

    2018-03-01

    The Gold mining generates large volumes of tailings, with consequent disposal and environmental problems. Iron tends to react with sulphur to form pyrite and pyrrhotite which then react with rain water forming acid rain. The study focuses on the removal of iron (Fe) from Gold Mine tailings; Fe was leached using citric acid as a leaching reagent. Three parameters which have an effect on the removal of Fe from the gold mine tailings, namely; temperature (25 °C and 50 °C), reagent concentration (0.25 M, 0.5 M, 0.75 M and 1 M) and solid loading ratio (20 %, 30 % and 40 %) were investigated. It was found that the recovery of Fe from gold mine tailings increased with increasing temperature and reagent concentration, but decreased with increasing solid loading ratio. The optimum conditions for the recovery of Fe from gold mine tailings was found to be at a temperature of 50 ºC, reagent concentration of 1 M and solid loading of 20 %. Three linear kinetic models were investigated and Prout-Tompkins kinetic model was the best fit yielding linear graphs with the highest R2 values.

  12. Activation of Graphene Oxide with Hydrochloric Acid for Nitrate Removal from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Abolghasem Alighardashi

    2017-11-01

    Full Text Available Long-term drinking of nitrate-contaminated water poses a serious risk to human health. The present study explores the possibility of enhancing the adsorption capacity of graphene oxide via activation with hydrochloric acid for nitrate removal from aqueous solutions. Experiments were performed in a batch reactor in which such major factors as pH, reaction time, and concentrations of both graphene oxide (GO and activated graphene oxide (AGO were used as variables. Nitrate removal efficiency was investigated using the One-Way ANOVA statistical test and SPSS-16 software. The chemical composition and solid structure of the synthesized AGO were analyzed using FE-SEM coupled with energy dispersive spectrometry (EDS. The micropore volumes of the samples were determined using the BET and BJH. The predominant composition (52% of the synthesized AGO was C and its mean pore diameter was 26.896 nm. The maximum adsorption capacity of AGO was estimated at 3333.33 mg/g. Based on the results, the AGO nano-structure may be recomended as a new means for nitrate removal from aqueous solutions.

  13. Batch Removal of Acid Blue 292dye by Biosorption onto Lemna minor: Equilibrium and Kinetic Studies

    Directory of Open Access Journals (Sweden)

    Ali Joghataei

    2016-12-01

    Full Text Available Background: Recently, there has been a great concern about the consumption of dyes because of their toxicity, mutagenicity, carcinogenicity, and persistence in the aquatic environment. Therefore, the aim of this study was to determine the feasibility of using Lemna minor for Acid Blue 292 (AB292 dye removal from aqueous solution and to determine the optimal conditions. Methods: This experimental study was conducted in the batch systems to investigate the effects of parameters such as contact time, initial concentration of dye, pH and Lemna minor biomass dose. Isotherms and kinetic studies of dye adsorption were performed using equilibrium data. Results: According to the results, a maximum removal efficiency of 98.5% was obtained at pH of 3 and the contact time of 90 min; initial dye concentration 10 mg/L and adsorbent dose 3g/L. The adsorption data was best fitted to the Langmuir isotherm and pseudo-second order kinetic model. Conclusion: The results showed that Lemna minor could be used as a cost-effective adsorbent for removing AB292 dye from textile wastewater efficiently.

  14. Removal of fission product ruthenium from purex process solutions: thiourea as complexing agent

    International Nuclear Information System (INIS)

    Floh, B.; Abrao, A.

    1980-01-01

    A new method for the treatment of spent uranium fuel is presented. It is based on the Purex Process using thiourea to increase the ruthenium decontamination factor. Thiourea exhibits a strong tendency for the formation of coordination compounds in acidic media. This tendency serves as a basis to transform nitrosyl-ruthenium species into Ru /SC(NH)(NH 2 )/ 2+ and Ru /SC(NH)(NH 2 )/ 3 complexes which are unextractable by TBP-varsol. The best conditions for the ruthenium-thiourea complex formation were found to be: thiourea-ruthenium ratio (mass/mass) close to 42, at 75 0 C, 30 minutes reaction time and aging period of 60 minutes. The ruthenium decontamination factor for a single uranium extraction are ca. 80-100, not interfering with extraction of actinides. These values are rather high in comparison to those obtained using the conventional Purex Process (e.g. F.D. sub(Ru)=10). By this reason the method developed here is suitable for the treatment of spent uranium fuels. Thiourea (100g/l) scrubbing experiments of ruthenium, partially co-extracted with actinides, confirmed the possibility of its removal from the extract. A decontamination greater than 83,5% for ruthenium as fission product is obtained in two stages with this procedure. (Author) [pt

  15. Removal of antibiotics from surface and distilled water in conventional water treatment processes

    Science.gov (United States)

    Adams, C.; Wang, Y.; Loftin, K.; Meyer, M.

    2002-01-01

    Conventional drinking water treatment processes were evaluated under typical water treatment plant conditions to determine their effectiveness in the removal of seven common antibiotics: carbadox, sulfachlorpyridazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfathiazole, and trimethoprim. Experiments were conducted using synthetic solutions prepared by spiking both distilled/ deionized water and Missouri River water with the studied compounds. Sorption on Calgon WPH powdered activated carbon, reverse osmosis, and oxidation with chlorine and ozone under typical plant conditions were all shown to be effective in removing the studied antibiotics. Conversely, coagulation/flocculation/sedimentation with alum and iron salts, excess lime/soda ash softening, ultraviolet irradiation at disinfection dosages, and ion exchange were all relatively ineffective methods of antibiotic removal. This study shows that the studied antibiotics could be effectively removed using processes already in use many water treatment plants. Additional work is needed on by-product formation and the removal of other classes of antibiotics.

  16. Improved methane removal in exhaust gas from biogas upgrading process using immobilized methane-oxidizing bacteria.

    Science.gov (United States)

    Sun, Meng-Ting; Yang, Zhi-Man; Fu, Shan-Fei; Fan, Xiao-Lei; Guo, Rong-Bo

    2018-05-01

    Methane in exhaust gas from biogas upgrading process, which is a greenhouse gas, could cause global warming. The biofilter with immobilized methane-oxidizing bacteria (MOB) is a promising approach for methane removal, and the selections of inoculated MOB culture and support material are vital for the biofilter. In this work, five MOB consortia were enriched at different methane concentrations. The MOB-20 consortium enriched at the methane concentration of 20.0% (v/v) was then immobilized on sponge and two particle sizes of volcanic rock in biofilters to remove methane in exhaust gas from biogas upgrading process. Results showed that the immobilized MOB performed more admirable methane removal capacity than suspended cells. The immobilized MOB on sponge reached the highest methane removal efficiency (RE) of 35%. The rough surface, preferable hydroscopicity, appropriate pore size and particle size of support material might favor the MOB immobilization and accordingly methane removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Simultaneous nitrogen and phosphorus removal in the sulfur cycle-associated Enhanced Biological Phosphorus Removal (EBPR) process.

    Science.gov (United States)

    Wu, Di; Ekama, George A; Wang, Hai-Guang; Wei, Li; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2014-02-01

    Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) of freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4(2-)/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production and oxygen demand. Recently, the SANI(®) process has been expanded to include Enhanced Biological Phosphorus Removal (EBPR) in an alternating anaerobic/limited-oxygen (LOS-EBPR) aerobic sequencing batch reactor (SBR). This paper presents further development - an anaerobic/anoxic denitrifying sulfur cycle-associated EBPR, named as DS-EBPR, bioprocess in an alternating anaerobic/anoxic SBR for simultaneous removal of organics, nitrogen and phosphorus. The 211 day SBR operation confirmed the sulfur cycle-associated biological phosphorus uptake utilizing nitrate as electron acceptor. This new bioprocess cannot only reduce operation time but also enhance volumetric loading of SBR compared with the LOS-EBPR. The DS-EBPR process performed well at high temperatures of 30 °C and a high salinity of 20% seawater. A synergistic relationship may exist between sulfur cycle and biological phosphorus removal as the optimal ratio of P-release to SO4(2-)-reduction is close to 1.0 mg P/mg S. There were no conventional PAOs in the sludge. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Investigation of combined coagulation and advanced oxidation process efficiency for the removal of Clarithromycin from wastewater

    Directory of Open Access Journals (Sweden)

    ahmad reza Yazdanbakhsh

    2011-06-01

    Conclusion: In general the results of the performed tests indicated that combined coagulation and advanced oxidation process has high efficiency in removal of Claritromycin wastewater COD. But application this method in the industry should be surveyed.

  19. Removal of micropollutants from municipal wastewater by graphene adsorption and simultaneous electrocoagulation/electrofiltration process.

    Science.gov (United States)

    Yang, Gordon C C; Tang, Pei-Ling; Yen, Chia-Heng

    2017-04-01

    In this work the optimal operating conditions for removing selected micropollutants (also known as emerging contaminants, ECs) from actual municipal wastewater by graphene adsorption (GA) and simultaneous electrocoagulation/electrofiltration (EC/EF) process, respectively, were first determined and evaluated. Then, performance and mechanisms for the removal of selected phthalates and pharmaceuticals from municipal wastewater simultaneously by the GA and EC/EF process were further assessed. ECs of concern included di-n-butyl phthalate (DnBP), di-(2-ethylhexyl) phthalate (DEHP), acetaminophen (ACE), caffeine (CAF), cefalexin (CLX) and sulfamethoxazole (SMX). It was found that GA plus EC/EF process yielded the following removal efficiencies: DnBP, 89 ± 2%; DEHP, 85 ± 3%; ACE, 99 ± 2%; CAF, 94 ± 3%; CLX, 100 ± 0%; and SMX, 98 ± 2%. Carbon adsorption, size exclusion, electrostatic repulsion, electrocoagulation, and electrofiltration were considered as the main mechanisms for the removal of target ECs by the integrated process indicated above.

  20. An overview on the removal of synthetic dyes from water by electrochemical advanced oxidation processes.

    Science.gov (United States)

    Nidheesh, P V; Zhou, Minghua; Oturan, Mehmet A

    2018-04-01

    Wastewater containing dyes are one of the major threats to our environment. Conventional methods are insufficient for the removal of these persistent organic pollutants. Recently much attention has been received for the oxidative removal of various organic pollutants by electrochemically generated hydroxyl radical. This review article aims to provide the recent trends in the field of various Electrochemical Advanced Oxidation Processes (EAOPs) used for removing dyes from water medium. The characteristics, fundamentals and recent advances in each processes namely anodic oxidation, electro-Fenton, peroxicoagulation, fered Fenton, anodic Fenton, photoelectro-Fenton, sonoelectro-Fenton, bioelectro-Fenton etc. have been examined in detail. These processes have great potential to destroy persistent organic pollutants in aqueous medium and most of the studies reported complete removal of dyes from water. The great capacity of these processes indicates that EAOPs constitute a promising technology for the treatment of the dye contaminated effluents. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. The Iron Removal in Marmatite Concentrate Pressure Leaching Process

    Science.gov (United States)

    Wen-bo, LUO; Ji-kun, WANG; Yin, GAN

    2018-01-01

    To modify the pressure leaching technology of horizontal autoclave using marmatite concentrate, an appropriate increase in the pulp’s residence time in the horizontal autoclave is required. This increase will provide sufficient time for leaching to be completed in the first three chambers of the horizontal autoclave. Adding zinc oxide ore and potassium sulfate in the fourth chamber of the horizontal autoclave is needed to complete preliminary neutralization and iron precipitation in the horizontal autoclave. The pilot plant experimental results of the proposed technology are satisfactory, further shortening the process of pressure leaching and improving its economic efficiency.

  2. Novel MBR_based main stream biological nutrient removal process: high performance and microbial community.

    Science.gov (United States)

    Zhang, Chuanyi; Xu, Xinhai; Zhao, Kuixia; Tang, Lianggang; Zou, Siqi; Yuan, Limei

    2018-02-01

    For municipal wastewater treatment, main stream biological nutrient removal (BNR) process is becoming more and more important. This lab-scale study, novel MBR_based BNR processes (named A 2 N-MBR and A 2 NO-MBR) were built. Comparison of the COD removal, results obtained demonstrated that COD removal efficiencies were almost the same in three processes, with effluent concentration all bellowed 30 mg L -1 . However, the two-sludge systems (A 2 N-MBR and A 2 NO-MBR) had an obvious advantage over the A 2 /O for denitrification and phosphorus removal, with the average TP removal rates of 91.20, 98.05% and TN removal rates of 73.00, 79.49%, respectively, higher than that of 86.45 and 61.60% in A 2 /O process. Illumina Miseq sequencing revealed that Candidatus_Accumulibacter, which is capable of using nitrate as an electron acceptor for phosphorus and nitrogen removal simultaneously, was the dominant phylum in both A 2 N-MBR and A 2 NO-MBR process, accounting for 28.74 and 23.98%, respectively. Distinguishingly, major organism groups related to nitrogen and phosphorus removal in A 2 /O system were Anaerolineaceae_uncultured, Saprospiraceae_uncultured and Thauera, with proportions of 11.31, 8.56 and 5.00%, respectively. Hence, the diversity of dominant PAOs group was likely responsible for the difference in nitrogen and phosphorus removal in the three processes.

  3. Selection of the Best Process Stream to Remove Ca2+ Ion Using Electrodialysis from Sugar Solution

    Directory of Open Access Journals (Sweden)

    Jogi Ganesh Dattatreya Tadimeti

    2014-01-01

    Full Text Available Electrodialytic removal of calcium chloride (CaCl2, 25–50 mol·m−3 from 5% sugar solution was executed in batch recirculation mode. Calcium ion removal rate was monitored with (i applied potential, (ii feed flow rate, (iii solution viscosity and conductivity, and (iv catholyte streams (NaOH or sodium salt of ethylene diamine tetraacetic acid-acetic acid, Na2EDTA-AA. Unsteady state model for ion concentration change was written for the ED cell used. Linearized Nernst-Planck equation instead of Ohm’s law was applied to closely obtain the current density and concentration change theoretically. The model developed could closely predict the experimental observation. Mass transfer coefficients and specific energy densities were estimated for each combination of catholyte stream used. NaOH showed better performance for a short duration over Na2EDTA-acetic acid combination.

  4. Removal of acid red 88 from wastewater by adsorption on agrobased waste material. A case study of Iranian golden Sesamum indicum hull

    Directory of Open Access Journals (Sweden)

    Mahmoud Zarei

    2017-08-01

    Full Text Available Background: Colors are very useful in different industries such as textile and leather but when they enter water, can cause many biological and environmental problems. In the present research, a waste agricultural material which is freely available is employed to analyze its efficiency for removing acid dye from contaminated wastewaters. Methods: In this study, batch adsorption experiments were performed in the treatment process of acid red 88 (AR88 by Iranian golden Sesamum indicum (IGSI seeds hull which is produced abundantly in some countries and especially in Iran up to 1100 kg/ha. Also, the effect of operational parameters like adsorption time, pH, dye concentration and adsorbent dosage was studied on pollutant removing efficiency. The experimental data of AR88 adsorption was fitted to Langmuir, Freundlich and Temkin isotherm models. The scanning electron microscopy (SEM images for the IGSI were taken before and after adsorption process. Results: The efficiency of dye adsorption on adsorbent was found to be 98.2%. The optimum pH for treatment was 4.5 which is in the acidic range. Enhancing the adsorbent dosage from 0.5 to 2.5 g caused increasing in removal efficiency from 73.85% to 95.85%. Decreasing in dye concentration from 70 to 30 mg/L caused increasing in removal efficiency from 79.73% to 95.83%. The process of adsorption was best fitted to Langmuir model and the amount of dye adsorbed on adsorbent, qe, was found to be 25 mg/g. Comparison between SEM images before and after dye adsorption, showed the significant difference that was due to the dye loading on adsorbent. Conclusion: The results of present study demonstrated higher dye removal efficiency for AR88 in acidic pHs. Employing the IGSI material in this study proves to be a potential alternative to expensive adsorbents, utilized for the treatment of contaminated industrial waste waters.

  5. Metal monitoring for process control of laser-based coating removal

    Science.gov (United States)

    Fraser, Mark E.; Hunter, Amy J.; Panagiotou, Thomai; Davis, Steven J.; Freiwald, David A.

    1999-12-01

    Cost-effective and environmentally-sound means of paint and coatings removal is a problem spanning many government, commercial, industrial and municipal applications. For example, the Department of Energy is currently engaged in removing paint and other coatings from concrete and structural steel as part of decommissioning former nuclear processing facilities. Laser-based coatings removal is an attractive new technology for these applications as it promises to reduce the waste volume by up to 75 percent. To function more efficiently, however, the laser-based systems require some form of process control.

  6. Aspen HYSYS process simulation and Aspen ICARUS cost estimation of CO2 removal plant

    OpenAIRE

    Vozniuk, Ievgeniia Oleksandrivna

    2010-01-01

    An Aspen HYSYS model of CO2 removal was developed and modified with a split-stream configuration in order to reduce energy consumption in the reboiler. The model has been calculated with variation of parameters to optimize the process and find an optimum solution. For the selected base cases the heat exchanger minimum temperature difference was specified to 10K and the removal efficiency was 85%. The reboiler duty of 3.8 MJ/kg CO2 removed for the standard process without split-stream was ...

  7. INVESTIGATION OF DENTURE REMOVAL PROCESS BY MEANS OF DESTRUCTION OF FIXING CEMENT BY ULTRASOUND ACTION

    Directory of Open Access Journals (Sweden)

    M. G. Kiselev

    2007-01-01

    Full Text Available The paper contains results of experimental investigations in respect of denture removal processes using as models so natural teeth as well and this removal process presupposes destruction of fixing cement by ultrasound action. It has been established that the best conditions for separation of a denture from a tooth body are ensured while ultrasound is acting on non-removable denture structure in liquid phase (water. At the expense of sound-capillary effect water fills in porous structure of fixing cement at high speed and a cavitation that appears in it leads to intensive cement destruction (dispersion.

  8. Rubber Fruit Shell (Hevea brasiliensis) as bio sorbent to remove FFA (Free Fatty Acid) content in CPO (Crude Palm Oil)

    Science.gov (United States)

    Pandia, S.; Sinaga, M. S.; Masyithah, Z.; Husin, A.; Nurfadilla, S.; Fitriani; Sipahutar, B. K. S.

    2018-02-01

    This study aimed to discover the effectiveness of the shell of rubber fruit as bio sorbent for removing FFA (Free Fatty Acid) content in CPO (Crude Palm Oil). Methods used in this study were pretreatment, activation (carbonating and chemically) and adsorption process at room temperature. In the beginning, the shell of rubber fruit was cleaned and dried under the sun. Then the shell was cut for about 0.5 cm of length and carbonated in a furnace for 1h at 600°C. After that, they were crushed to pass through 140 meshes and activated using three variations of chemical such as 6 of HNO3, 6N of KOH and 6N of H3PO4 at certain ratio as 1:3, 1:4, and 1:5 (b/v). The adsorption process was carried out using bio sorbent with the highest iodine number in varying bio sorbent dosage and contact time. The highest iodine number was 913.680 mg/g and obtained at the ratio of bio sorbent to 6N of KOH as 1:5. The best removal of FFA content was 91.94% and at 1% bio sorbent dose and 30 min of contact time.

  9. Trivalent chromium removal from aqueous solutions by a sol–gel synthesized silica adsorbent functionalized with sulphonic acid groups

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Gonzalez, Sergio Efrain [Departamento de Ingeniería Química, Universidad de Guadalajara, Blvd. Marcelino García Barragán # 1421, esq. Calzada Olímpica, C.P. 44430 Guadalajara, Jalisco (Mexico); Carbajal-Arizaga, Gregorio Guadalupe [Departamento de Química, CUCEI, Universidad de Guadalajara, Blvd. Marcelino García Barragán # 1421, esq. Calzada Olímpica, C.P. 44430 Guadalajara, Jalisco (Mexico); Manriquez-Gonzalez, Ricardo [Departamento de Madera, Celulosa y Papel, CUCEI, Universidad de Guadalajara, Km 15.5, carretera Guadalajara-Nogales, Las Agujas, C.P. 45020 Zapopan, Jalisco (Mexico); De la Cruz-Hernandez, Wencel [Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Km 107 carretera Tijuana-Ensenada, C.P. 22830 Ensenada, Baja California (Mexico); Gomez-Salazar, Sergio, E-mail: sergio.gomez@cucei.udg.mx [Departamento de Ingeniería Química, Universidad de Guadalajara, Blvd. Marcelino García Barragán # 1421, esq. Calzada Olímpica, C.P. 44430 Guadalajara, Jalisco (Mexico)

    2014-11-15

    Highlights: • Corpuscular sulphonic acid-functionalized silica holds improved uptake of chromium. • Mesopores on adsorbent facilitate (CH{sub 3}COO){sub 2}Cr{sup +} ion uptake on sulphonate sites. • Formation of chromium acetate sulphonate complex proposed from XPS results. • Fixed bed chromium uptake results suggest potential industrial use. - Abstract: A high capacity hybrid silica adsorbent was synthesized via sol–gel processing with sulphonic acid groups as trivalent chromium complex ions chelators from aqueous solutions. The synthesis included co-condensation of tetraethoxysilane (TEOS) with 3-(mercaptopropyl)trimethoxysilane (MPS), and oxidation of thiol to sulphonic acid groups. Chromium uptake kinetic, batch and fixed-bed experiments were performed to assess the removal of this metal from aqueous solutions. {sup 13}C, {sup 29}Si CPMAS NMR, FTIR, XPS were used to characterize the adsorbent structure and the nature of chromium complexes on the adsorbent surface. Chromium maximum uptake was obtained at pH 3 (72.8 mg/g). Elemental analysis results showed ligand density of 1.48 mmol sulphonic groups/g. About 407 mL of Cr(III) solution (311 mg/L) were treated to breakthrough point reaching ≤0.06 mg/L at the effluent. These results comply with USEPA regulation for chromium concentration in drinking water (≤0.1 mg/L). The adsorbent shows potential to be used in chromium separations to the industrial level.

  10. Trivalent chromium removal from aqueous solutions by a sol–gel synthesized silica adsorbent functionalized with sulphonic acid groups

    International Nuclear Information System (INIS)

    Gomez-Gonzalez, Sergio Efrain; Carbajal-Arizaga, Gregorio Guadalupe; Manriquez-Gonzalez, Ricardo; De la Cruz-Hernandez, Wencel; Gomez-Salazar, Sergio

    2014-01-01

    Highlights: • Corpuscular sulphonic acid-functionalized silica holds improved uptake of chromium. • Mesopores on adsorbent facilitate (CH 3 COO) 2 Cr + ion uptake on sulphonate sites. • Formation of chromium acetate sulphonate complex proposed from XPS results. • Fixed bed chromium uptake results suggest potential industrial use. - Abstract: A high capacity hybrid silica adsorbent was synthesized via sol–gel processing with sulphonic acid groups as trivalent chromium complex ions chelators from aqueous solutions. The synthesis included co-condensation of tetraethoxysilane (TEOS) with 3-(mercaptopropyl)trimethoxysilane (MPS), and oxidation of thiol to sulphonic acid groups. Chromium uptake kinetic, batch and fixed-bed experiments were performed to assess the removal of this metal from aqueous solutions. 13 C, 29 Si CPMAS NMR, FTIR, XPS were used to characterize the adsorbent structure and the nature of chromium complexes on the adsorbent surface. Chromium maximum uptake was obtained at pH 3 (72.8 mg/g). Elemental analysis results showed ligand density of 1.48 mmol sulphonic groups/g. About 407 mL of Cr(III) solution (311 mg/L) were treated to breakthrough point reaching ≤0.06 mg/L at the effluent. These results comply with USEPA regulation for chromium concentration in drinking water (≤0.1 mg/L). The adsorbent shows potential to be used in chromium separations to the industrial level

  11. Rapid microwave-assisted acid extraction of southern pine waste wood to remove metals from chromated copper arsenate (CCA) treatment

    Science.gov (United States)

    Chung-Yun Hse; Todd F. Shupe; Bin Yu

    2013-01-01

    Recovery of metals from chromated copper arsenate (CCA)-treated southern pine wood particles was investigated by extraction in a microwave reactor with binary combinations of acetic acid (AA), oxalic acid (OxA), and phosphoric acid (PhA). Use of OxA was not successful, as insoluble copper oxalate complexes impeded copper removal. The combination of OxA and AA also had...

  12. Uranium removal from organic solutions of PUREX process

    International Nuclear Information System (INIS)

    Dell'Occhio, L.A.; Dupetit, G.A.; Pascale, A.A.; Vicens, H.E.

    1987-01-01

    During the uranium extraction process with tributyl phosphate (TBP) in nitric medium, a bi solvated, non hydrated complex is formed, of formula UO2(NO3)2TBP, which is soluble in the diluent, a paraffin hydrocarbon. As it is known that some uranium salts, for instance the nitrate, when dissolved in organic solvents, like isopropanol, can be discharged as complex molecules at the cathode of an electrodeposition cell, it was decided to apply this technique to uranium loaded TBP solutions. From preliminary experiments resulted a practical possibility for the analytical control through the alpha measurement of electro deposits. This technique could be applied as well to the treatment of depleted organic streams carrying undesirable alpha activity, because the so treated solutions become deprived of uranium. This work presents the curves obtained working at constant voltage with uranium-loaded TBP solutions, the determination of the optimal operation voltage in these conditions, the electrodeposition yield for electro polished copper and stainless steel cathodes and the tests of reproducibility of deposits. A summary of the results obtained operating the high voltage supply at constant power is also presented. (Author)

  13. Control of a Biological Nitrogen Removal Process in an Intensified Single Reactor Configuration

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mauricio Iglesias, Miguel; Gernaey, Krist

    2013-01-01

    The nitrogen removing granular sludge process is a novel and intensified process. However, its stable operation and control remains a challenging problem. In this contribution, a new process oriented approach is used to develop, evaluate and benchmark control strategies to ensure stable operation...

  14. Extracorporeal Carbon Dioxide Removal Enhanced by Lactic Acid Infusion in Spontaneously Breathing Conscious Sheep.

    Science.gov (United States)

    Scaravilli, Vittorio; Kreyer, Stefan; Belenkiy, Slava; Linden, Katharina; Zanella, Alberto; Li, Yansong; Dubick, Michael A; Cancio, Leopoldo C; Pesenti, Antonio; Batchinsky, Andriy I

    2016-03-01

    The authors studied the effects on membrane lung carbon dioxide extraction (VCO2ML), spontaneous ventilation, and energy expenditure (EE) of an innovative extracorporeal carbon dioxide removal (ECCO2R) technique enhanced by acidification (acid load carbon dioxide removal [ALCO2R]) via lactic acid. Six spontaneously breathing healthy ewes were connected to an extracorporeal circuit with blood flow 250 ml/min and gas flow 10 l/min. Sheep underwent two randomly ordered experimental sequences, each consisting of two 12-h alternating phases of ALCO2R and ECCO2R. During ALCO2R, lactic acid (1.5 mEq/min) was infused before the membrane lung. Caloric intake was not controlled, and animals were freely fed. VCO2ML, natural lung carbon dioxide extraction, total carbon dioxide production, and minute ventilation were recorded. Oxygen consumption and EE were calculated. ALCO2R enhanced VCO2ML by 48% relative to ECCO2R (55.3 ± 3.1 vs. 37.2 ± 3.2 ml/min; P less than 0.001). During ALCO2R, minute ventilation and natural lung carbon dioxide extraction were not affected (7.88 ± 2.00 vs. 7.51 ± 1.89 l/min, P = 0.146; 167.9 ± 41.6 vs. 159.6 ± 51.8 ml/min, P = 0.063), whereas total carbon dioxide production, oxygen consumption, and EE rose by 12% each (223.53 ± 42.68 vs. 196.64 ± 50.92 ml/min, 215.3 ± 96.9 vs. 189.1 ± 89.0 ml/min, 67.5 ± 24.0 vs. 60.3 ± 20.1 kcal/h; P less than 0.001). ALCO2R was effective in enhancing VCO2ML. However, lactic acid caused a rise in EE that made ALCO2R no different from standard ECCO2R with respect to ventilation. The authors suggest coupling lactic acid-enhanced ALCO2R with active measures to control metabolism.

  15. The synthesis of alternatives for the bioconversion of waste-monoethanolamine from large-scale CO{sub 2}-removal processes

    Energy Technology Data Exchange (ETDEWEB)

    Ohtaguchi, Kazuhisa; Yokoyama, Takahisa [Tokyo Inst. of Tech. (Japan). Dept. of Chemical Engineering

    1998-12-31

    The alternatives for bioconversion of monoethanolamine (MEA), which would appear in large quantities in industrial effluent of CO{sub 2}-removal process of power companies, have been proposed by investigating the ability of some microorganisms to deaminate MEA. An evaluation of biotechnology, which includes productions from MEA of acetic acid and acetaldehyde with Escherichia coli, of formic and acetic acids with Clostridium formicoaceticum, confirms and extends our earlier remarks on availability of ecotechnology for solving the above problem. (Author)

  16. Sulfur Removal by Adding Iron During the Digestion Process of High-sulfur Bauxite

    Science.gov (United States)

    Zhanwei, Liu; Hengwei, Yan; Wenhui, Ma; Keqiang, Xie; Dunyong, Li; Licong, Zheng; Pengfei, Li

    2018-04-01

    This paper proposes a novel approach to sulfur removal by adding iron during the digestion process. Iron can react with high-valence sulfur (S2O3 2-, SO3 2-, SO4 2-) to generate S2- at digestion temperature, and then S2- enter red mud in the form of Na3FeS3 to be removed. As iron dosage increases, high-valence sulfur concentration decreases, but the concentration of S2- increases; sulfur digestion rate decreases while sulfur content in red mud markedly increases; the alumina digestion rate, conversely, remains fairly stable. So sulfur can be removed completely by adding iron in digestion process, which provide a theoretical basis for the effective removal of sulfur in alumina production process.

  17. Technology study on removal of Ra, U, Mn and F from the acid wastewater of uranium mining and metallurgy

    International Nuclear Information System (INIS)

    Wu Yongyong; Zhong Pingru; Wang Gaoshan

    2014-01-01

    The laboratory study for decreasing the concentration of Ra, U, Mn and F ions in acid wastewater of uranium mining and metallurgy was investigated based on lime neutralization-precipitation technology. The technological flowsheet was composed of removing radium by barium chloride, manganese by air aeration and fluorin by aluminum sulfate, and the quality of the disposed effluent could be accorded with the discharge criteria defined by the state, as the neutralization conditions of pH just being 8.5. Furthermore, the lower precipitation pH value can effectively decrease sediment volume, and reduce the subsequent processing pressures. The technological methods were viable and universally applicable for uranium mining and metallurgy wastewater purification. (authors)

  18. A multi-process phytoremediation system for removal of polycyclic aromatic hydrocarbons from contaminated soils

    International Nuclear Information System (INIS)

    Huang Xiaodong; El-Alawi, Yousef; Penrose, Donna M.; Glick, Bernard R.; Greenberg, Bruce M.

    2004-01-01

    To improve phytoremediation processes, multiple techniques that comprise different aspects of contaminant removal from soils have been combined. Using creosote as a test contaminant, a multi-process phytoremediation system composed of physical (volatilization), photochemical (photooxidation) and microbial remediation, and phytoremediation (plant-assisted remediation) processes was developed. The techniques applied to realize these processes were land-farming (aeration and light exposure), introduction of contaminant degrading bacteria, plant growth promoting rhizobacteria (PGPR), and plant growth of contaminant-tolerant tall fescue (Festuca arundinacea). Over a 4-month period, the average efficiency of removal of 16 priority PAHs by the multi-process remediation system was twice that of land-farming, 50% more than bioremediation alone, and 45% more than phytoremediation by itself. Importantly, the multi-process system was capable of removing most of the highly hydrophobic, soil-bound PAHs from soil. The key elements for successful phytoremediation were the use of plant species that have the ability to proliferate in the presence of high levels of contaminants and strains of PGPR that increase plant tolerance to contaminants and accelerate plant growth in heavily contaminated soils. The synergistic use of these approaches resulted in rapid and massive biomass accumulation of plant tissue in contaminated soil, putatively providing more active metabolic processes, leading to more rapid and more complete removal of PAHs. - Persistent PAH contaminants in soils can be removed more completely and rapidly by using multiple remediation processes

  19. Study of the removal of metronidazole from aqueous solutions using Electro/ Fenton process and graphite and iron electrodes

    Directory of Open Access Journals (Sweden)

    Bahram Kamarehie

    2018-04-01

    Conclusion: The Electro-Fenton process can effectively remove metronidazole from aquatic solutions in environmentally convenient conditions. This process can be used as an efficient method for removing other persistent pollutants from the environment.

  20. Unit Process Wetlands for Removal of Trace Organic Contaminants and Pathogens from Municipal Wastewater Effluents

    Science.gov (United States)

    Jasper, Justin T.; Nguyen, Mi T.; Jones, Zackary L.; Ismail, Niveen S.; Sedlak, David L.; Sharp, Jonathan O.; Luthy, Richard G.; Horne, Alex J.; Nelson, Kara L.

    2013-01-01

    Abstract Treatment wetlands have become an attractive option for the removal of nutrients from municipal wastewater effluents due to their low energy requirements and operational costs, as well as the ancillary benefits they provide, including creating aesthetically appealing spaces and wildlife habitats. Treatment wetlands also hold promise as a means of removing other wastewater-derived contaminants, such as trace organic contaminants and pathogens. However, concerns about variations in treatment efficacy of these pollutants, coupled with an incomplete mechanistic understanding of their removal in wetlands, hinder the widespread adoption of constructed wetlands for these two classes of contaminants. A better understanding is needed so that wetlands as a unit process can be designed for their removal, with individual wetland cells optimized for the removal of specific contaminants, and connected in series or integrated with other engineered or natural treatment processes. In this article, removal mechanisms of trace organic contaminants and pathogens are reviewed, including sorption and sedimentation, biotransformation and predation, photolysis and photoinactivation, and remaining knowledge gaps are identified. In addition, suggestions are provided for how these treatment mechanisms can be enhanced in commonly employed unit process wetland cells or how they might be harnessed in novel unit process cells. It is hoped that application of the unit process concept to a wider range of contaminants will lead to more widespread application of wetland treatment trains as components of urban water infrastructure in the United States and around the globe. PMID:23983451

  1. Unit Process Wetlands for Removal of Trace Organic Contaminants and Pathogens from Municipal Wastewater Effluents.

    Science.gov (United States)

    Jasper, Justin T; Nguyen, Mi T; Jones, Zackary L; Ismail, Niveen S; Sedlak, David L; Sharp, Jonathan O; Luthy, Richard G; Horne, Alex J; Nelson, Kara L

    2013-08-01

    Treatment wetlands have become an attractive option for the removal of nutrients from municipal wastewater effluents due to their low energy requirements and operational costs, as well as the ancillary benefits they provide, including creating aesthetically appealing spaces and wildlife habitats. Treatment wetlands also hold promise as a means of removing other wastewater-derived contaminants, such as trace organic contaminants and pathogens. However, concerns about variations in treatment efficacy of these pollutants, coupled with an incomplete mechanistic understanding of their removal in wetlands, hinder the widespread adoption of constructed wetlands for these two classes of contaminants. A better understanding is needed so that wetlands as a unit process can be designed for their removal, with individual wetland cells optimized for the removal of specific contaminants, and connected in series or integrated with other engineered or natural treatment processes. In this article, removal mechanisms of trace organic contaminants and pathogens are reviewed, including sorption and sedimentation, biotransformation and predation, photolysis and photoinactivation, and remaining knowledge gaps are identified. In addition, suggestions are provided for how these treatment mechanisms can be enhanced in commonly employed unit process wetland cells or how they might be harnessed in novel unit process cells. It is hoped that application of the unit process concept to a wider range of contaminants will lead to more widespread application of wetland treatment trains as components of urban water infrastructure in the United States and around the globe.

  2. Cobalt and organics removal effect using fiber filter/reverse osmosis combination process for LLRW from korean PWR NPP

    International Nuclear Information System (INIS)

    Park, S.M.; Yang, H.Y.; Song, M.J.

    2001-01-01

    Evaporation system for liquid radioactive waste process has been used in Korean PWR nuclear power plants. The system is the most desirable process for decontamination factor (DF) theoretically. However, during the operation of the system, various problems have been arising such as scaling, carry over, etc. Because these problems make DF low, advanced technologies for liquid radwaste process have been world widely developed instead of keeping evaporation system. The main goal of new technologies is ALARA, ease of operation, cost effectiveness and minimization of environmental effect. Korea Electric Power Corporation is currently developing a combined treatment process for liquid radwaste using Micro-filter, Ultra-filter, Reverse Osmosis (RO) membrane, etc for the purpose of partly enhancement of evaporator and of having an alternative liquid radwaste process system for new reactors. As a part of the above project, the feasibility study using the Rolled Fiber-Filter (RFF) and RO membrane has been carried out. This paper reports the results of lab-test from the combined process of the fiber filtration and RO membrane module for cobalt and organics removal. The study was especially focused on the boric acid permeation in the RO unit. Because boric acid occupies large volume of the final waste after evaporation process, the new technology such as RO process has to be studied on the boron process. (author)

  3. Investigation of Phenol Removal by Proxy-Electrocoagulation Process with Iron Electrodes from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Ali Assadi

    2017-09-01

    Full Text Available Background: Phenol as an aromatic hydroxyl compound are considered as a priority pollutant. Because of their stability, solubility in water and high toxicity had health important. Methods: In the present experimental study, electrocoagulation reactor by iron electrodes are used in the presence of hydrogen peroxide to phenol removing from aqueous solutions. Effects of variables including H2O2 dosage, reaction time, pH, current density and initial phenol concentration were evaluated to estimate the efficiency of the process. Results: The results showed that pH and H2O2 have the most important role in the removal of phenol. Increasing of H2O2 concentrations from 0.0125 to 0.025 M increased removal efficiency from 74% to 100%. Maximum removal was achieved at pH=3. However, increasing the pH to 9 lead to reducing removal efficiency to 9.8%. Also, by increasing of current density removal efficiency was increased. But with increasing initial concentration of phenol removal efficiency was reduced. Conclusion: Proxy-electrocoagulation process as an effective and robust process can be used for handling of phenol containing wastewater.

  4. Removal of chlortetracycline from spiked municipal wastewater using a photoelectrocatalytic process operated under sunlight irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Daghrir, Rimeh, E-mail: rimeh.daghrir@ete.inrs.ca [Institut National de la Recherche Scientifique, Centre Eau, Terre et Environnement, 490 rue de la Couronne, Québec, Qc G1K 9A9 (Canada); Drogui, Patrick, E-mail: patrick.drogui@ete.inrs.ca [Institut National de la Recherche Scientifique, Centre Eau, Terre et Environnement, 490 rue de la Couronne, Québec, Qc G1K 9A9 (Canada); Delegan, Nazar, E-mail: delegan@emt.inrs.ca [Institut National de la Recherche Scientifique, INRS-Énergie, Matériaux et Télécommunications, 1650 Blvd. Lionel-Boulet, Varennes, Qc J3X 1S2 (Canada); El Khakani, My Ali, E-mail: elkhakani@emt.inrs.ca [Institut National de la Recherche Scientifique, INRS-Énergie, Matériaux et Télécommunications, 1650 Blvd. Lionel-Boulet, Varennes, Qc J3X 1S2 (Canada)

    2014-01-01

    The degradation of chlortetracycline in synthetic solution and in municipal effluent was investigated using a photoelectrocatalytic oxidation process under visible irradiation. The N-doped TiO{sub 2} used as photoanode with 3.4 at.% of nitrogen content was prepared by means of a radiofrequency magnetron sputtering (RF-MS) process. Under visible irradiation, higher photoelectrocatalytic removal efficiency of CTC was recorded using N-doped TiO{sub 2} compared to the conventional electrochemical oxidation, direct photolysis and photocatalysis processes. The photoelectrocatalytic process operated at 0.6 A of current intensity during 180 min of treatment time promotes the degradation of 99.1 ± 0.1% of CTC. Under these conditions, removal rates of 85.4 ± 3.6%, 87.4 ± 3.1% and 55.7 ± 2.9% of TOC, TN and NH{sub 4}{sup +} have been recorded. During the treatment, CTC was mainly transformed into CO{sub 2} and H{sub 2}O. The process was also found to be effective in removing indicator of pathogens such as fecal coliform (log-inactivation was higher than 1.2 units). - Highlights: •PECO process is a feasible technology for the treatment of MWW contaminated by CTC. •99.1% ± 0.1% of CTC was degraded by PECO using N-doped TiO{sub 2}. •85.4% ± 3.6% of TOC removal and 97.5% ± 1.2% of COD removal were achieved. •87.4% ± 3.1% of TN removal and 55.7% ± 2.9% of NH{sub 4}{sup +} removal were recorded. •More than 94% of fecal coliform was removed (abatement > 1.2-log units)

  5. Degradation of 2,4-dichlorophenoxyacetic acid in water by ozone-hydrogen peroxide process

    Institute of Scientific and Technical Information of China (English)

    YU Ying-hui; MA Jun; HOU Yan-jun

    2006-01-01

    This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O3/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation of 2,4-dichlorophenoxyacetic acid was studied under different H2O2/O3 molar ratio and pH value. Meanwhile, TOC removal was investigated both in distilled water and tap water. The influences of ozone transfer and consumed hydrogen peroxide were also discussed. The degradation products and oxidation intermediates were identified by GC-MS and LC-MS. A possible reaction mechanism was thus proposed.

  6. Uranium recovery from wet-process phosphoric acid

    International Nuclear Information System (INIS)

    McCullough, J.F.; Phillips, J.F. Jr.; Tate, L.R.

    1979-01-01

    A method of recovering uranium from wet-process phosphoric acid is claimed where the acid is treated with a mixture of an ammonium salt or ammonia, a reducing agent, and then a miscible solvent. Solids are separated from the phosphoric acid liquid phase. The solid consists of a mixture of metal phosphates and uranium. It is washed free of adhering phosphoric acid with fresh miscible solvent. The solid is dried and dissolved in acid whereupon uranium is recovered from the solution. Miscible solvent and water are distilled away from the phosphoric acid. The distillate is rectified and water discarded. All miscible solvent is recovered for recycle. 5 claims

  7. Removal of Acid Black 194 dye from water by electrocoagulation with aluminum anode.

    Science.gov (United States)

    Vidal, Jorge; Villegas, Loreto; Peralta-Hernández, Juan M; Salazar González, Ricardo

    2016-01-01

    Application of an electrocoagulation process (EC) for the elimination of AB194 textile dye from synthetic and textile wastewater (effluent) contaminated with AB194 dye, was carried out using aluminum anodes at two different initial pH values. Tafel studies in the presence and absence of the dye were performed. The aluminum species formed during the electrolysis were quantified by atomic absorption, and the flocs formed in the process were analyzed by HPLC-MS. Complete removal of AB194 from 1.0 L of solution was achieved applying low densities current at initial pH values of 4.0 and 8.0. The removal of AB194 by EC was possible with a short electrolysis time, removing practically 100% of the total organic carbon content and chemical oxygen demand. The final result was completely discolored water lacking dye and organic matter. An effluent contaminated with 126 mg L(-1) AB194 dye from a Chilean textile industry was also treated by EC under optimized experimental conditions, yielding discolored water and considerably decreasing the presence of organic compounds (dye + dyeing additives), with very low concentrations of dissolved Al(3+). Analysis of flocs showed the presence of the original dye without changes in its chemical structure.

  8. Selective removal/recovery of RCRA metals from waste and process solutions using polymer filtration{trademark} technology

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.F. [Los Alamos National Lab., NM (United States)

    1997-10-01

    Resource Conservation and Recovery Act (RCRA) metals are found in a number of process and waste streams at many DOE, U.S. Department of Defense, and industrial facilities. RCRA metals consist principally of chromium, mercury, cadmium, lead, and silver. Arsenic and selenium, which form oxyanions, are also considered RCRA elements. Discharge limits for each of these metals are based on toxicity and dictated by state and federal regulations (e.g., drinking water, RCRA, etc.). RCRA metals are used in many current operations, are generated in decontamination and decommissioning (D&D) operations, and are also present in old process wastes that require treatment and stabilization. These metals can exist in solutions, as part of sludges, or as contaminants on soils or solid surfaces, as individual metals or as mixtures with other metals, mixtures with radioactive metals such as actinides (defined as mixed waste), or as mixtures with a variety of inert metals such as calcium and sodium. The authors have successfully completed a preliminary proof-of-principle evaluation of Polymer Filtration{trademark} (PF) technology for the dissolution of metallic mercury and have also shown that they can remove and concentrate RCRA metals from dilute solutions for a variety of aqueous solution types using PF technology. Another application successfully demonstrated is the dilute metal removal of americium and plutonium from process streams. This application was used to remove the total alpha contamination to below 30 pCi/L for the wastewater treatment plant at TA-50 at Los Alamos National Laboratory (LANL) and from nitric acid distillate in the acid recovery process at TA-55, the Plutonium Facility at LANL (ESP-CP TTP AL16C322). This project will develop and optimize the PF technology for specific DOE process streams containing RCRA metals and coordinate it with the needs of the commercial sector to ensure that technology transfer occurs.

  9. Selective removal/recovery of RCRA metals from waste and process solutions using polymer filtration trademark technology

    International Nuclear Information System (INIS)

    Smith, B.F.

    1997-01-01

    Resource Conservation and Recovery Act (RCRA) metals are found in a number of process and waste streams at many DOE, U.S. Department of Defense, and industrial facilities. RCRA metals consist principally of chromium, mercury, cadmium, lead, and silver. Arsenic and selenium, which form oxyanions, are also considered RCRA elements. Discharge limits for each of these metals are based on toxicity and dictated by state and federal regulations (e.g., drinking water, RCRA, etc.). RCRA metals are used in many current operations, are generated in decontamination and decommissioning (D ampersand D) operations, and are also present in old process wastes that require treatment and stabilization. These metals can exist in solutions, as part of sludges, or as contaminants on soils or solid surfaces, as individual metals or as mixtures with other metals, mixtures with radioactive metals such as actinides (defined as mixed waste), or as mixtures with a variety of inert metals such as calcium and sodium. The authors have successfully completed a preliminary proof-of-principle evaluation of Polymer Filtration trademark (PF) technology for the dissolution of metallic mercury and have also shown that they can remove and concentrate RCRA metals from dilute solutions for a variety of aqueous solution types using PF technology. Another application successfully demonstrated is the dilute metal removal of americium and plutonium from process streams. This application was used to remove the total alpha contamination to below 30 pCi/L for the wastewater treatment plant at TA-50 at Los Alamos National Laboratory (LANL) and from nitric acid distillate in the acid recovery process at TA-55, the Plutonium Facility at LANL (ESP-CP TTP AL16C322). This project will develop and optimize the PF technology for specific DOE process streams containing RCRA metals and coordinate it with the needs of the commercial sector to ensure that technology transfer occurs

  10. Adsorption Removal of Glycidyl Esters from Palm Oil and Oil Model Solution by Using Acid-Washed Oil Palm Wood-Based Activated Carbon: Kinetic and Mechanism Study.

    Science.gov (United States)

    Cheng, Weiwei; Liu, Guoqin; Wang, Xuede; Han, Lipeng

    2017-11-08

    Acid-washed oil palm wood-based activated carbon (OPAC) has been investigated for its potential application as a promising adsorbent in the removal of glycidyl esters (GEs) from both palm oil and oil model (hexadecane) solution. It was observed that the removal rate of GEs in palm oil was up to >95%, which was significantly higher than other adsorbents used in this study. In batch adsorption system, the adsorption efficiency and performance of acid-washed OPAC were evaluated as a function of several experimental parameters such as contact time, initial glycidyl palmitate (PGE) concentration, adsorbent dose, and temperature. The Langmuir, Freundlich, and Dubinin-Radushkevich models were used to describe the adsorption equilibrium isotherm, and the equilibrium data were fitted best by the Langmuir model. The maximum adsorption capacity of acid-washed OPAC was found to be 36.23 mg/g by using the Langmuir model. The thermodynamic analysis indicated that the adsorption of PGE on acid-washed OPAC was an endothermic and physical process in nature. The experimental data were fitted by using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. It was found that the kinetic of PGE adsorption onto acid-washed OPAC followed well the pseudo-second-order model for various initial PGE concentrations and the adsorption process was controlled by both film diffusion and intraparticle diffusion. The desorption test indicated the removal of GEs from palm oil was attributed to not only the adsorption of GEs on acid-washed OPAC, but also the degradation of GEs adsorbed at activated sites with acidic character. Furthermore, no significant difference between before and after PGE adsorption in oil quality was observed.

  11. Removal of oil pollutants in seawater as pretreatment of reverse osmosis desalination process

    Energy Technology Data Exchange (ETDEWEB)

    Wen Jian; Nishijima, Wataru; Baes, Aloysius U.; Okada, Mitsumasa [Hiroshima Univ., Environmental Science Dept., Hiroshima (Japan); Kitanaka, Atsushi [Fuji-Electric Corporate Research and Development Ltd., Yokosuka, Kanagawa (Japan)

    1999-11-01

    Weathered oil contaminated seawater (WOCS) was used to investigate the behaviour of soluble oil components in seawater in various pretreatment processes for removal of oil pollutants in seawater. The various pretreatment processes were a reverse osmosis desalination process in combination with advanced oxidation processes, ultrafiltration, coagulation, GAC adsorption, biological treatment and separation with a low pressure RO membrane. WOCS was prepared by mixing oil, nutrients and fresh seawater which was exposed to sunlight to simulate photooxidation and microbial degradation of oil in the marine environment. It was found that WOCS contained soluble components with relatively small molecular size, which are refractory to biodegradation and difficult to remove by advanced oxidation processes (AOPs), UF membrane or coagulation using FeCl{sub 3} or PAC as flocculants. However, DOC in WOCS (OCWOCS) was easily adsorbed to GAC. Low pressure RO membranes with higher salt rejection rate could remove more OCWOCS compared to those of lower salt rejection rate. (Author)

  12. Removal of oil pollutants in seawater as pretreatment of reverse osmosis desalination process

    Energy Technology Data Exchange (ETDEWEB)

    Wen Jian; Nishijima, Wataru; Baes, Aloysius U.; Okada, Mitsumasa [Hiroshima Univ., Environmental Science Dept., Hiroshima (Japan); Kitanaka, Atsushi [Fuji-Electric Corporate Research and Development Ltd., Yokosuka, Kanagawa (Japan)

    1999-07-01

    Weathered oil contaminated seawater (WOCS) was used to investigate the behaviour of soluble oil components in seawater in various pretreatment processes for removal of oil pollutants in seawater. The various pretreatment processes were a reverse osmosis desalination process in combination with advanced oxidation processes, ultrafiltration, coagulation, GAC adsorption, biological treatment and separation with a low pressure RO membrane. WOCS was prepared by mixing oil, nutrients and fresh seawater which was exposed to sunlight to simulate photooxidation and microbial degradation of oil in the marine environment. It was found that WOCS contained soluble components with relatively small molecular size, which are refractory to biodegradation and difficult to remove by advanced oxidation processes (AOPs), UF membrane or coagulation using FeCl{sub 3} or PAC as flocculants. However, DOC in WOCS (OCWOCS) was easily adsorbed to GAC. Low pressure RO membranes with higher salt rejection rate could remove more OCWOCS compared to those of lower salt rejection rate. (Author)

  13. Regeneration of an aqueous solution from an acid gas absorption process by matrix stripping

    Science.gov (United States)

    Rochelle, Gary T [Austin, TX; Oyenekan, Babatunde A [Katy, TX

    2011-03-08

    Carbon dioxide and other acid gases are removed from gaseous streams using aqueous absorption and stripping processes. By replacing the conventional stripper used to regenerate the aqueous solvent and capture the acid gas with a matrix stripping configuration, less energy is consumed. The matrix stripping configuration uses two or more reboiled strippers at different pressures. The rich feed from the absorption equipment is split among the strippers, and partially regenerated solvent from the highest pressure stripper flows to the middle of sequentially lower pressure strippers in a "matrix" pattern. By selecting certain parameters of the matrix stripping configuration such that the total energy required by the strippers to achieve a desired percentage of acid gas removal from the gaseous stream is minimized, further energy savings can be realized.

  14. Mathematical Modeling of Nitrous Oxide Production during Denitrifying Phosphorus Removal Process.

    Science.gov (United States)

    Liu, Yiwen; Peng, Lai; Chen, Xueming; Ni, Bing-Jie

    2015-07-21

    A denitrifying phosphorus removal process undergoes frequent alternating anaerobic/anoxic conditions to achieve phosphate release and uptake, during which microbial internal storage polymers (e.g., Polyhydroxyalkanoate (PHA)) could be produced and consumed dynamically. The PHA turnovers play important roles in nitrous oxide (N2O) accumulation during the denitrifying phosphorus removal process. In this work, a mathematical model is developed to describe N2O dynamics and the key role of PHA consumption on N2O accumulation during the denitrifying phosphorus removal process for the first time. In this model, the four-step anoxic storage of polyphosphate and four-step anoxic growth on PHA using nitrate, nitrite, nitric oxide (NO), and N2O consecutively by denitrifying polyphosphate accumulating organisms (DPAOs) are taken into account for describing all potential N2O accumulation steps in the denitrifying phosphorus removal process. The developed model is successfully applied to reproduce experimental data on N2O production obtained from four independent denitrifying phosphorus removal study reports with different experimental conditions. The model satisfactorily describes the N2O accumulation, nitrogen reduction, phosphate release and uptake, and PHA dynamics for all systems, suggesting the validity and applicability of the model. The results indicated a substantial role of PHA consumption in N2O accumulation due to the relatively low N2O reduction rate by using PHA during denitrifying phosphorus removal.

  15. Advanced oxidative processes and membrane separation for micropollutant removal from biotreated domestic wastewater.

    Science.gov (United States)

    Silva, Larissa L S; Sales, Julio C S; Campos, Juacyara C; Bila, Daniele M; Fonseca, Fabiana V

    2017-03-01

    The presence of micropollutants in sewage is already widely known, as well as the effects caused by natural and synthetic hormones. Thus, it is necessary to apply treatments to remove them from water systems, such as advanced oxidation processes (AOPs) and membrane separation processes, which can oxidize and remove high concentrations of organic compounds. This work investigated the removal of 17β-estradiol (E2), 17α-ethinylestradiol (EE2), and estriol (E3) from biotreated sewage. Reverse osmosis processes were conducted at three recoveries (50, 60, and 70 %). For E2 and EE2, the removals were affected by the recovery. The best results for RO were as follows: the E2 compound removal was 89 % for 60 % recovery and the EE2 compound removal was 57 % for 50 % recovery. The RO recovery did not impact the E3 removal. It was concluded that the interaction between the evaluated estrogens, and the membrane was the major factor for the hormone separation. The AOP treatment using H 2 O 2 /UV was carried out in two sampling campaigns. First, we evaluated the variation of UV doses (24.48, 73.44, 122.4, and 244.8 kJ m -2 ) with 18.8 mg L -1 of H 2 O 2 in the reaction. EE2 showed considerable removals (around 70 %). In order to optimize the results, an experimental design was applied. The best result was obtained with higher UV dose (122.4 kJ m -2 ) and lower H 2 O 2 concentration (4 mg L -1 ), achieving removal of 91 % for E3 and 100 % for E2 and EE2.

  16. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    Directory of Open Access Journals (Sweden)

    Jafari Mohammad Javad

    2012-12-01

    Full Text Available Abstract The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p 3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream.

  17. Removal of palladium precipitate from a simulated high-level radioactive liquid waste by reduction by ascorbic acid

    International Nuclear Information System (INIS)

    Kim, Eung Ho; Yoo, Jae Hyung; Choi, Cheong Song

    1998-01-01

    A study of the selective removal of Palladium from a simulated solution of high-level radioactive liquid waste (HLLW) was carried out. The simulated solution contained 7 representative elements (Pd 2+ , Cs + , Sr 2+ , Fe 3+ , MoO 2 2+ , Ru 4+ , and Nd 3+ ) typical of HLLW, ascorbic acid was added to the solution at room temperature. Pd 2+ in the simulated solution was easily reduced to Pd metal by the ascorbic acid and then the metal precipitate could be removed from the solution, whereas other elements remained mainly in solution. When the resulting Pd metal was left in solution, it was reoxidized to Pb 2+ ion and redissolved in a nitric acid medium. The oxidation rate of Pd 2+ depended on the presence of a transition metal such as ferric ion, and was also in proportion to the concentration of nitric acid and in inverse proportion to the concentration of ascrobic acid. (orig.)

  18. Removal of carbamazepine and clofibric acid from water using double templates-molecularly imprinted polymers.

    Science.gov (United States)

    Dai, Chao-meng; Zhang, Juan; Zhang, Ya-lei; Zhou, Xue-fei; Duan, Yan-ping; Liu, Shu-guang

    2013-08-01

    A novel double templates-molecularly imprinted polymer (MIP) was prepared by precipitation polymerization using carbamazepine (CBZ) and clofibric acid (CA) as the double templates molecular and 2-vinylpyridine as functional monomer. The equilibrium data of MIP was well described by the Freundlich isotherm model. Two kinetic models were adopted to describe the experimental data, and the pseudo second-order model well-described adsorption of CBZ and CA on the MIP. Adsorption experimental results showed that the MIP had good selectivity and adsorption capacity for CBZ and CA in the presence of competitive compounds compared with non-imprinted polymer, commercial powdered activated carbon, and C18 adsorbents. The feasibility of removing CBZ and CA from water by the MIP was demonstrated using tap water, lake water, and river water.

  19. Application of Electrocoagulation Process Using Iron and Aluminum Electrodes for Fluoride Removal from Aqueous Environment

    Directory of Open Access Journals (Sweden)

    Edris Bazrafshan

    2012-01-01

    Full Text Available Fluoride in drinking water above permissible level is responsible for human being affected by skeletal fluorosis. The present study was carried out to assess the ability of electrocoagulation process with iron and aluminum electrodes in order to removal of fluoride from aqueous solutions. Several working parameters, such as fluoride concentration, pH, applied voltage and reaction time were studied to achieve a higher removal capacity. Variable concentrations (1, 5 and 10 mg L-1 of fluoride solutions were prepared by mixing proper amount of sodium fluoride with deionized water. The varying pH of the initial solution (3, 7 and 10 was also studied to measure their effects on the fluoride removal efficiency. Results obtained with synthetic solution revealed that the most effective removal capacities of fluoride could be achieved at 40 V electrical potential. In addition, the increase of electrical potential, in the range of 10-40 V, enhanced the treatment rate. Also comparison of fluoride removal efficiency showed that removal efficiency is similar with iron and aluminum electrodes. Finally it can be concluded that the electrocoagulation process has the potential to be utilized for the cost-effective removal of fluoride from water and wastewater.

  20. Optimizing Electrocoagulation Process for the Removal of Nitrate From Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Dehghani

    2016-01-01

    Full Text Available Background High levels of nitrate anion are frequently detected in many groundwater resources in Fars province. Objectives The present study aimed to determine the removal efficiency of nitrate from aqueous solutions by electrocoagulation process using aluminum and iron electrodes. Materials and Methods A laboratory-scale batch reactor was conducted to determine nitrate removal efficiency using the electrocoagulation method. The removal of nitrate was determined at pH levels of 3, 7, and 11, different voltages (15, 20, and 30 V, and operation times of 30, 60, and 75 min, respectively. Data were analyzed using the SPSS software version 16 (Chicago, Illinois, USA and Pearson’s correlation coefficient was used to analyze the relationship between the parameters. Results Results of the present study showed that the removal efficiency was increased from 27% to 86% as pH increased from 3 to 11 at the optimal condition of 30 V and 75 min operation time. Moreover, by increasing the reaction time from 30 V to 75 min the removal efficiency was increased from 63% to 86%, respectively (30 V and pH = 11. Pearson’s correlation analysis showed that there was a significant relationship between removal efficiency and voltage and reaction time as well (P < 0.01. Conclusions In conclusion, the electrocoagulation process can be used for removing nitrate from water resources because of high efficiency, simplicity, and relatively low cost.

  1. Simplified model of SO2 removal from industrial gas in e-beam process

    International Nuclear Information System (INIS)

    Bouzyk, J.; Sowinski, M.

    1997-01-01

    The analysis of SO 2 and, on the part, NO x removal mechanism by e-beam process has been discussed. It is estimated that radiation contribution to SO 2 removal amounts to 40% while in the case of NO x it appears to reach about 70%. Taking into account the main reactions responsible for SO 2 oxidation as well as the assumption presented in our previous paper an algorithm has been developed to describe linear kinetics of the process. The principal assumption referred to depends on OH radical concentration to be nearly stable. The concept of an extended model of NO x /SO 2 removal has been presented and the literature data have been used to check the suggested model. On that basis the general idea has been proposed for controlling SO 2 /NO x removal which comprises both the simplified and extended pathway. (author)

  2. Performance of wind-powered soil electroremediation process for the removal of 2,4-D from soil.

    Science.gov (United States)

    Souza, F L; Llanos, J; Sáez, C; Lanza, M R V; Rodrigo, M A; Cañizares, P

    2016-04-15

    In this work, it is studied a wind-powered electrokinetic soil flushing process for the removal of pesticides from soil. This approach aims to develop an eco-friendly electrochemical soil treatment technique and to face the in-situ treatment of polluted soils at remote locations. Herbicide 2,4 dichlorophenoxyacetic acid (2,4-D) is selected as a model pollutant for the soil treatment tests. The performance of the wind-powered process throughout a 15 days experiment is compared to the same remediation process powered by a conventional DC power supply. The wind-powered test covered many different wind conditions (from calm to near gale), being performed 20.7% under calm conditions and 17% under moderate or gentle breeze. According to the results obtained, the wind-powered soil treatment is feasible, obtaining a 53.9% removal of 2,4-D after 15 days treatment. Nevertheless, the remediation is more efficient if it is fed by a constant electric input (conventional DC power supply), reaching a 90.2% removal of 2,4-D with a much lower amount of charge supplied (49.2 A h kg(-1) and 4.33 A h kg(-1) for wind-powered and conventional) within the same operation time. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Effect of propionic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    Science.gov (United States)

    Xu, Jian; Bao, Jia-Wei; Su, Xian-Feng; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2016-03-01

    In this study, an integrated citric acid-methane fermentation process was established to solve the problem of wastewater treatment in citric acid production. Citric acid wastewater was treated through anaerobic digestion and then the anaerobic digestion effluent (ADE) was further treated and recycled for the next batch citric acid fermentation. This process could eliminate wastewater discharge and reduce water resource consumption. Propionic acid was found in the ADE and its concentration continually increased in recycling. Effect of propionic acid on citric acid fermentation was investigated, and results indicated that influence of propionic acid on citric acid fermentation was contributed to the undissociated form. Citric acid fermentation was inhibited when the concentration of propionic acid was above 2, 4, and 6 mM in initial pH 4.0, 4.5 and, 5.0, respectively. However, low concentration of propionic acid could promote isomaltase activity which converted more isomaltose to available sugar, thereby increasing citric acid production. High concentration of propionic acid could influence the vitality of cell and prolong the lag phase, causing large amount of glucose still remaining in medium at the end of fermentation and decreasing citric acid production.

  4. Removal of some basic dyes by poly (Vinyl Alcohol/ acrylic acid)Hydrogel

    International Nuclear Information System (INIS)

    Hegazy, S.A.; Abdel-AAl, S.E.; Abdel-Rehim, H.A.; Khalifa, N.A.; El-Hosseiny, E.M.

    2000-01-01

    A study has made on the preparation and properties of poly (vinyl alcohol/ acrylic acid) hydrogel for the purpose of removal of cationic dyes from aqueous solutions. The effect of dose and monomer concentration on the uptake property of the hydrogel toward dye was studied. The uptake of basic methylene blue-9 dye with PVA/AAc was studied by the batch adsorption technique. The effect of pH on the dye uptake was demonstrated to find out that the suitable pH for maximum uptake occurred at pH 5. It was observed that as the concentration of dye is increased the dye uptake decreased. Furthermore, the uptake of dye by hydrogels increased as the temperature was elevated. The recovery of dye adsorbed is possible by treating the hydrogel with 5% HCl. The results obtained suggested this hydrogel possessed good removal properties towards basic methylene blue-9 dye, and this suggests that such hydrogels could be acceptable for practical uses

  5. Ball-milling effect on Indonesian natural bentonite for manganese removal from acid mine drainage

    Directory of Open Access Journals (Sweden)

    Prastistho Widyawanto

    2018-01-01

    Full Text Available The influences of mechanical milling on Indonesian Natural Bentonite (INB characteristics and manganese (Mn removal from acid mine drainage (AMD were investigated. The INB characteristics were observed by scanning electron microscope (SEM, X-ray diffraction (XRD, nitrogen adsorption-desorption for specific surface area (SSA and microporosity measurement, cation exchange capacity (CEC and particle size distribution (PSD analyzer. Four minutes milling with frequency 20 Hz on INB caused morphological change which showed more crumbled and destructed particle, lost the (001 peak but still retained the (100 peak that indicated delamination of montmorillonite mineral without breaking the tetrahedral-octahedral-tetrahedral (T-O-T structure, rose the CEC from 28.49 meq/100g to 35.51 meq/100g, increase in the SSA from 60.63 m2/g to 104.88 m2/g, significant increase in microporosity which described in the t plots and decrease in the mean particle size distribution peak from 49.28 μm to 38.84 μm. The effect of contact time and effect of adsorbent dosage on Mn sorption was studied. Both unmilled and milled samples reached equilibrium at 24 hours and the pH rose from 4 to 7 in first 30 minutes. The Mn removal percentage increased significantly after milling. Using Langmuir isotherm, the maximum adsorbed metals (qmax also increased from 0.570 to 4.219 mg/g.

  6. Synthesis of surfactant-coated cobalt ferrite nanoparticles for adsorptive removal of acid blue 45 dye

    Science.gov (United States)

    Waheed Mushtaq, Muhammad; Kanwal, Farah; Imran, Muhammad; Ameen, Naila; Batool, Madeeha; Batool, Aisha; Bashir, Shahid; Mustansar Abbas, Syed; Rehman, Ata ur; Riaz, Saira; Naseem, Shahzad; Ullah, Zaka

    2018-03-01

    Cobalt ferrite (CoFe2O4) nanoparticles (NPs) are synthesized by wet chemical coprecipitation method using metal chlorides as precursors and potassium hydroxide (KOH) as a precipitant. The tergitol-1x (T-1x) and didecyldimethyl ammonium bromide (DDAB) are used as capping agents and their effect is investigated on particle size, size distribution and morphology of cobalt ferrite nanoparticles (CFNPs). The Fourier transform infrared spectroscopy confirms the synthesis of CFNPs and formation of metal-oxygen (M-O) bond. The spinel phase structure, morphology, polydispersity and magnetic properties of ferrite nanoparticles are investigated by x-ray diffraction, scanning electron microscopy, dynamic light scattering and vibrating sample magnetometry analyses, respectively. The addition of capping agents effects the secondary growth of CFNPs and reduces their particle size, as is investigated by dynamic light scattering and atomic force microscopy. The results evidence that the DDAB is more promising surfactant to control the particle size (∼13 nm), polydispersity and aggregation of CFNPs. The synthesized CFNPs, CFNPs/T-1x and CFNPs/DDAB are used to study their adsorption potential for removal of acid blue 45 dye, and a maximum adsorptive removal of 92.25% is recorded by 0.1 g of CFNPs/DDAB at pH 2.5 and temperature 20 ± 1 °C. The results show that the dye is physically adsorbed by magnetic NPs and follows the Langmuir isotherm model.

  7. POTENTIAL USE OF WOOL WASTE AS ADSORBENT FOR THE REMOVAL OF ACID DYES FROM WASTEWATER

    Directory of Open Access Journals (Sweden)

    BUCIŞCANU Ingrid

    2016-05-01

    Full Text Available At present, great amounts of raw wool are treated as waste and raise disposal problems. In the sustainable development context , wool is regarded as a biodegradable renewable resource and due to its complex chemical composition and fiber morphology, can find different useful applications. It is the aim of this paper to investigate the potential use of raw wool waste as a non-conventional adsorbent for Acid Red 337(AcR ,currently used for leather and wool dyeing. Two wool-based adsorbents were prepared, namely scoured coarse wool (Wool-S and wool activated with alcoholic solution of sodium hydroxide (Wool-A. Adsorbent dosage, dye concentration, pH and treatment time were factors taken in consideration for the assessment of the sorbate-adsorbent interaction. The removal efficiency (R % is mainly dependent on the solution pH and on the activation treatment applied to wool: at pH 3, the removal efficiency reaches the highest values of 42% on Wool-S and 99% on Wool-A. The adsorption rate is slow and needs almost 6 h to reach equilibrium. The experimental data best fitted the Langmuir equilibrium adsorption model, which proves that the adsorbent possess surface active sites to which the dye sorbate binds in monomolecular layer. Raw wool waste is a potential cheap, biodegradable and effective adsorbent for colored wastewater treatment.

  8. Improvements in iodine and ruthenium removal from advanced liquid processing system

    Energy Technology Data Exchange (ETDEWEB)

    Skibo, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-27

    SRNL has considerable experience in designing, engineering, and operating systems for removing iodine-129 (I-129) and ruthenium-106 (Ru-106) from waste streams that are directly analogous to the Advanced Liquid Processing System (ALPS) waste streams. SRNL proposes to provide the technical background and design and engineering support for an improved I-129 and Ru-106 removal system for application to ALPS on the Fukushima Daiichi Nuclear Power Station (NPS).

  9. Physical removal of metallic carbon nanotubes from nanotube network devices using a thermal and fluidic process

    International Nuclear Information System (INIS)

    Ford, Alexandra C; Shaughnessy, Michael; Wong, Bryan M; Kane, Alexander A; Krafcik, Karen L; Léonard, François; Kuznetsov, Oleksandr V; Billups, W Edward; Hauge, Robert H

    2013-01-01

    Electronic and optoelectronic devices based on thin films of carbon nanotubes are currently limited by the presence of metallic nanotubes. Here we present a novel approach based on nanotube alkyl functionalization to physically remove the metallic nanotubes from such network devices. The process relies on preferential thermal desorption of the alkyls from the semiconducting nanotubes and the subsequent dissolution and selective removal of the metallic nanotubes in chloroform. The approach is versatile and is applied to devices post-fabrication. (paper)

  10. H/sub 2/S-removal processes for low-Btu coal gas

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, M. S.

    1979-01-01

    Process descriptions are provided for seven methods of removing H/sub 2/S from a low-Btu coal-derived gas. The processes include MDEA, Benfield, Selexol, Sulfinol, Stretford, MERC Iron Oxide, and Molecular Sieve. Each of these processes was selected as representing a particular category of gas treating (e.g., physical solvent systems). The open literature contains over 50 processes for H/sub 2/S removal, of which 35 were briefly characterized in the literature survey. Using a technical evaluation of these 35 processes, 21 were eliminated as unsuitable for the required application. The remaining 14 processes represent six categories of gas treating. A seventh category, low-temperature solid sorption, was subsequently added. The processes were qualitatively compared within their respective categories to select a representative process in each of the seven categories.

  11. Development of an improved ion-exchange process for removing cesium and strontium from high-level radioactive liquid wastes

    International Nuclear Information System (INIS)

    Wallace, R.M.; Ferguson, R.B.

    1980-11-01

    Processes are being developed to solidify and isolate the biologically hazardous radionuclides from approximately 23 million gallons of alkaline high-level waste accumulated at the Savannah River Plant. The waste consists mainly of a liquid supernate, a damp salt cake, and a gelatinous, insoluble sludge. The reference solidification process involves separation of the water soluble fraction (supernate) from the insoluble fraction, removal of cesium and traces of strontium from the supernate, incorporation of the sludge and the radionuclides from the supernate in glass, and incorporation of the residual salt in concrete. A new process, now being developed, involves sorbing cesium on phenolic resins that contain no strongly acidic sulfonate groups. These resins can then be eluted with formic acid which is not possible with Duolite ARC-359. Duolite CS-100, a phenol-carboxylate resin, was chosen for further development because of its greater breakthrough capacity and because it also sorbs strontium to some extent. Strontium sorption by CS-100 was not sufficient to eliminate the need for Amberlite IRC-718. However, the latter resin can also be eluted with formic acid because its functional groups are weakly acidic. Formic acid elution permits several options to be considered. The preferred option consists simply of mixing the eluate with sludge prior to calcination. Sodium formate, which is formed when the resins in the sodium form are eluted, decomposes rapidly between 450 0 C and 500 0 C and will be destroyed in either the calciner or the melter. The resulting sodium oxide would be incorporated into glass. The principal advantage of the new process is the elimination of a number of process steps

  12. Enhanced pharmaceutical removal from water in a three step bio-ozone-bio process.

    Science.gov (United States)

    de Wilt, Arnoud; van Gijn, Koen; Verhoek, Tom; Vergnes, Amber; Hoek, Mirit; Rijnaarts, Huub; Langenhoff, Alette

    2018-07-01

    Individual treatment processes like biological treatment or ozonation have their limitations for the removal of pharmaceuticals from secondary clarified effluents with high organic matter concentrations (i.e. 17 mg TOC/L). These limitations can be overcome by combining these two processes for a cost-effective pharmaceutical removal. A three-step biological-ozone-biological (BO 3 B) treatment process was therefore designed for the enhanced pharmaceutical removal from wastewater effluent. The first biological step removed 38% of ozone scavenging TOC, thus proportionally reducing the absolute ozone input for the subsequent ozonation. Complementariness between biological and ozone treatment, i.e. targeting different pharmaceuticals, resulted in cost-effective pharmaceutical removal by the overall BO 3 B process. At a low ozone dose of 0.2 g O 3 /g TOC and an HRT of 1.46 h in the biological reactors, the removal of 8 out of 9 pharmaceuticals exceeded 85%, except for metoprolol (60%). Testing various ozone doses and HRTs revealed that pharmaceuticals were ineffectively removed at 0.1 g O3/g TOC and an HRT of 0.3 h. At HRTs of 0.47 and 1.46 h easily and moderately biodegradable pharmaceuticals such as caffeine, gemfibrozil, ibuprofen, naproxen and sulfamethoxazole were over 95% removed by biological treatment. The biorecalcitrant carbamazepine was completely ozonated at a dose of 0.4 g O 3 /g TOC. Ozonation products are likely biodegraded in the last biological reactor as a 17% TOC removal was found. No appreciable acute toxicity towards D. magna, P. subcapitata and V. fischeri was found after exposure to the influents and effluents of the individual BO 3 B reactors. The BO 3 B process is estimated to increase the yearly wastewater treatment tariff per population equivalent in the Netherlands by less than 10%. Overall, the BO 3 B process is a cost-effective treatment process for the removal of pharmaceuticals from secondary clarified effluents. Copyright

  13. Standard practice for fluorescent liquid penetrant testing using the Solvent-Removable process

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice covers procedures for fluorescent penetrant examination utilizing the solvent-removable process. It is a nondestructive testing method for detecting discontinuities that are open to the surface, such as cracks, seams, laps, cold shuts, laminations, isolated porosity, through leaks, or lack of fusion and is applicable to in-process, final, and maintenance examination. It can be effectively used in the examination of nonporous, metallic materials, both ferrous and nonferrous, and of nonmetallic materials such as glazed or fully densified ceramics and certain nonporous plastics and glass. 1.2 This practice also provides a reference: 1.2.1 By which a fluorescent penetrant examination solvent-removable process recommended or required by individual organizations can be reviewed to ascertain its applicability and completeness. 1.2.2 For use in the preparation of process specifications dealing with the fluorescent solvent-removable liquid penetrant examination of materials and parts. Agreement by th...

  14. Development of a solvent extraction process for cesium removal from SRS tank waste

    International Nuclear Information System (INIS)

    Leonard, R.A.; Conner, C.; Liberatore, M.W.; Sedlet, J.; Aase, S.B.; Vandegrift, G.F.; Delmau, L.H.; Bonnesen, P.V.; Moyer, B.A.

    2001-01-01

    An alkaline-side solvent extraction process was developed for cesium removal from Savannah River Site (SRS) tank waste. The process was invented at Oak Ridge National Laboratory and developed and tested at Argonne National Laboratory using singlestage and multistage tests in a laboratory-scale centrifugal contactor. The dispersion number, hydraulic performance, stage efficiency, and general operability of the process flowsheet were determined. Based on these tests, further solvent development work was done. The final solvent formulation appears to be an excellent candidate for removing cesium from SRS tank waste.

  15. Occurrence of pharmaceuticals in a municipal wastewater treatment plant: mass balance and removal processes.

    Science.gov (United States)

    Gao, Pin; Ding, Yunjie; Li, Hui; Xagoraraki, Irene

    2012-06-01

    Occurrence and removal efficiencies of fifteen pharmaceuticals were investigated in a conventional municipal wastewater treatment plant in Michigan. Concentrations of these pharmaceuticals were determined in both wastewater and sludge phases by a high-performance liquid chromatograph coupled to a tandem mass spectrometer. Detailed mass balance analysis was conducted during the whole treatment process to evaluate the contributing processes for pharmaceutical removal. Among the pharmaceuticals studied, demeclocycline, sulfamerazine, erythromycin and tylosin were not detected in the wastewater treatment plant influent. Other target pharmaceuticals detected in wastewater were also found in the corresponding sludge phase. The removal efficiencies of chlortetracycline, tetracycline, sulfamerazine, acetaminophen and caffeine were >99%, while doxycycline, oxytetracycline, sulfadiazine and lincomycin exhibited relatively lower removal efficiencies (e.g., <50%). For sulfamethoxazole, the removal efficiency was approximately 90%. Carbamazepine manifested a net increase of mass, i.e. 41% more than the input from the influent. Based on the mass balance analysis, biotransformation is believed to be the predominant process responsible for the removal of pharmaceuticals (22% to 99%), whereas contribution of sorption to sludge was relatively insignificant (7%) for the investigated pharmaceuticals. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Partial Nitrification and Denitrifying Phosphorus Removal in a Pilot-Scale ABR/MBR Combined Process.

    Science.gov (United States)

    Wu, Peng; Xu, Lezhong; Wang, Jianfang; Huang, Zhenxing; Zhang, Jiachao; Shen, Yaoliang

    2015-11-01

    A pilot-scale combined process consisting of an anaerobic baffled reactor (ABR) and an aerobic membrane bioreactor (MBR) for the purpose of achieving easy management, low energy demands, and high efficiencies on nutrient removal from municipal wastewater was investigated. The process operated at room temperature with hydraulic retention time (HRT) of 7.5 h, recycle ratio 1 of 200%, recycle ratio 2 of 100%, and dissolved oxygen (DO) of 1 mg/L and achieved good effluent quality with chemical oxygen demand (COD) of 25 mg/L, NH4 (+)-N of 4 mg/L, total nitrogen (TN) of 11 mg/L, and total phosphorus (TP) of 0.7 mg/L. The MBR achieved partial nitrification, and NO2 (-)-N has been accumulated (4 mg/L). Efficient short-cut denitrification was occurred in the ABR with a TN removal efficiency of 51%, while the role of denitrification and phosphorus removal removed partial TN (14%). Furthermore, nitrogen was further removed (11%) by simultaneous nitrification and denitrification in the MBR. In addition, phosphorus accumulating organisms in the MBR sufficiently uptake phosphorus; thus, effluent TP further reduced with a TP removal efficiency of 84%. Analysis of fluorescence in situ hybridization (FISH) showed that ammonia oxidizing bacteria (AOB) and phosphorus accumulating organisms (PAOs) were enriched in the process. In addition, the accumulation of NO2 (-)-N was contributed to the inhibition on the activities of the NOB rather than its elimination.

  17. Process Simulation and Cost Analysis for Removing Inorganics from Wood Chips using Combined Mechanical and Chemical Preprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Hongqiang; Westover, Tyler L.; Cherry, Robert; Aston, John E.; Lacey, Jeffrey A.; Thompson, David N.

    2016-10-01

    Naturally occurring and introduced inorganic species (ash) in biomass feedstocks negatively impact thermochemical energy conversion processes such as pyrolysis, hydrothermal liquefaction, gasification and combustion to biopower. As such, it is desirable to better understand the cost:benefit ratios of various ash reduction processes. Here, a novel process simulation model was developed using AspenPlus to reduce the ash content of Loblolly logging residues using both air classification and a dilute-acid leaching process. For costing purposes, a throughput of 25 tons/hour was selected. At this scale, the process cost for a standalone air classification process was $3 per ton for a biomass feedstock. Ash reduction via dilute –acid leaching was simulated based on experimentally determined kinetics of ion diffusion at an acid concentration of 0.5% H2SO4 and temperature of 75°F. The total estimated processing cost for leaching at these conditions was approximately $14/ton of dry biomass. Sensitivity analysis of three parameters on mineral reduction in the leaching process revealed that increasing leaching temperature was not economically feasible, while it was viable to apply a longer retention time in leaching for higher ash removal or achieve a lower water content in final products with reasonable extra costs. In addition, scenarios combining air classification with leaching were examined. A whole process cost of approximately $16/ton of biomass at a biomass feedstock rate of 25 ton/hour considering a 9% of biomass classified as light fraction to be leached. The leaching operating costs constituted 75% of this amount, of which the heating costs of dryer was 44%. This suggests that the process costs would be substantially reduced if more efficient drying methods are applied in future.

  18. Processing of nuclear power plant waste streams containing boric acid

    International Nuclear Information System (INIS)

    1996-10-01

    Boric acid is used in PWR type reactor's primary coolant circuit to control the neutron flux. However, boric acid complicates the control of water chemistry of primary coolant and the liquid radioactive waste produced from NPP. The purpose of this report is to provide member states with up-to-date information and guidelines for the treatment and conditioning of boric acid containing wastes. It contains chapters on: (a) characteristics of waste streams; (b) options for management of boric acid containing waste; (c) treatment/decontamination of boric acid containing waste; (d) concentration and immobilization of boric acid containing waste; (e) recovery and re-use of boric acid; (f) selected industrial processes in various countries; and (g) the influence of economic factors on process selection. 72 refs, 23 figs, 5 tabs

  19. Investigation of Phenol Removal from Aqueous Solutions by Electrofenton and Electropersulfate Processes

    Directory of Open Access Journals (Sweden)

    Alireza Rahmani

    2016-11-01

    Full Text Available Phenol, or benzene hydroxyl is a toxic aromatic hydrocarbon discharged into the environment through certian industrial effluents which, thereby, pollute water resources. This study examines phenol removal from aqueous solutions through electro-Fenton and electro/persulfate processes using iron electrodes. For this purpose, a laboratory-scale electrochemical batch reactor was used that was equipped with four electrodes and a direct DC power supply. In the tests carried out, the effects of operational parameters such as initial pH; current density; and initial concentrations of phenol, hydrogen peroxide, and persulfate on the removal of phenol were investigated. The results showed that EPS and EF processes achieved phenol removal efficiencies of 95.18% and 93.99%, respectively, at operating conditions of pH = 3, initial phenol concentration of 100 mg/l, hydrogen peroxide and persulfate concentration of 0. 4 mM, and a current density 0.07A/dm2 over 45 min. Increasing persulfate and hydrogen peroxide concentration from 0.4 to 0.8 mM reduced phenol removal efficiencies from 95.18% and 93.99% to 43% and 85%, respectively. Generally speaking, EPS and EF processes exhibited almost identical phenol removal efficiencies. Finally, the integrated electrochemical and persulphate process was found to be more productive in producing electrical iron and persulphate activation than using each single process in isolation.

  20. Enhanced pharmaceutical removal from water in a three step bio-ozone-bio process

    NARCIS (Netherlands)

    Wilt, de Arnoud; Gijn, van Koen; Verhoek, Tom; Vergnes, Amber; Hoek, Mirit; Rijnaarts, Huub; Langenhoff, Alette

    2018-01-01

    Individual treatment processes like biological treatment or ozonation have their limitations for the removal of pharmaceuticals from secondary clarified effluents with high organic matter concentrations (i.e. 17 mg TOC/L). These limitations can be overcome by combining these two processes for a

  1. External Carbon Source Addition as a Means to Control an Activated Sludge Nutrient Removal Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens; Søeberg, Henrik

    1994-01-01

    In alternating type activated sludge nutrient removal processes, the denitrification rate can be limited by the availability of readily-degradable carbon substrate. A control strategy is proposed by which an easily metabolizable COD source is added directly to that point in the process at which d...

  2. Enhancing the natural removal of As in a reactive fluvial confluence receiving acid drainage

    Science.gov (United States)

    Abarca, M. I.; Arce, G.; Montecinos, M.; Guerra, P. A.; Pasten, P.

    2014-12-01

    Fluvial confluences are natural reactors that can determine the fate of contaminants in watersheds receiving acid drainage. Hydrological, hydrodynamic and chemical factors determine distinct conditions for the formation of suspended particles of iron and aluminum oxyhydroxides. The chemical and physical properties of these particle assemblages (e.g. particle size, chemical composition) can vary according to inflow mixing ratios, hydrodynamic velocity profiles, and chemical composition of the flows mixing at the confluence. Due to their capacity to sorb metals, it is important to identify the optimal conditions for removing metals from the aqueous phase, particularly arsenic, a contaminant frequently found in acid drainage. We studied a river confluence in the Lluta watershed, located in the arid Chilean Altiplano. We performed field measurements and laboratory studies to find optimal mixing ratio for arsenic sorption onto oxyhydroxide particles at the confluence between the Azufre (pH=2, As=2 mg/L) and the Caracarani river (pH=8, Ascontaminants. An analogy between confluences and coagulation-flocculation-sedimentation drinking water plants could be used to engineer such intervention.Acknowledgements: Proyecto Fondecyt 1130936 and Proyecto CONICYT FONDAP 15110020

  3. Study on the removal of iron impurities in methanesulfonic acid tin plating bath

    Science.gov (United States)

    Hou-li, LIU; Jian-Jun, CHEN; Hong-Liang, PAN

    2018-03-01

    This thesis investigated the the influence of sodium sulfite as reducing agent on the recovery rate of tin ion. The approach is that HZ016 type cation exchange resin was used to adsorb Sn2+ and Fe2+ in electroplated tin solution first. After adsorption, the resin was removed by sulfuric acid, which was added with NaOH to adjust pH value to form precipitation and separate tin. X-ray diffraction (XRD) and energy spectrum (EDS) method were used to analyze the composition of the precipitates adjusted by pH. The results show that when the mass ratio of resin to bath is 1:2, the adsorption efficiency of resin reaches 98.3% and 97.1% respectively, and the elution efficiency of tin and iron reaches 95.1% and 94% respectively when the mass ratio of resin to eluent sulfuric acid is 1:4. Sodium sulfite was added to increase the efficiency of tin recovery by 8.1%. EDS and XRD atlas showed that after pH regulation, the main composition of the filtration precipitation was the hydroxides of tin.

  4. Investigation on thiosulfate-involved organics and nitrogen removal by a sulfur cycle-based biological wastewater treatment process.

    Science.gov (United States)

    Qian, Jin; Lu, Hui; Cui, Yanxiang; Wei, Li; Liu, Rulong; Chen, Guang-Hao

    2015-02-01

    Thiosulfate, as an intermediate of biological sulfate/sulfite reduction, can significantly improve nitrogen removal potential in a biological sulfur cycle-based process, namely the Sulfate reduction-Autotrophic denitrification-Nitrification Integrated (SANI(®)) process. However, the related thiosulfate bio-activities coupled with organics and nitrogen removal in wastewater treatment lacked detailed examinations and reports. In this study, S2O3(2-) transformation during biological SO4(2-)/SO3(2-) co-reduction coupled with organics removal as well as S2O3(2-) oxidation coupled with chemolithotrophic denitrification were extensively evaluated under different experimental conditions. Thiosulfate is produced from the co-reduction of sulfate and sulfite through biological pathway at an optimum pH of 7.5 for organics removal. And the produced S2O3(2-) may disproportionate to sulfide and sulfate during both biological S2O3(2-) reduction and oxidation most possibly carried out by Desulfovibrio-like species. Dosing the same amount of nitrate, pH was found to be the more direct factor influencing the denitritation activity than free nitrous acid (FNA) and the optimal pH for denitratation (7.0) and denitritation (8.0) activities were different. Spiking organics significantly improved both denitratation and denitritation activities while minimizing sulfide inhibition of NO3(-) reduction during thiosulfate-based denitrification. These findings in this study can improve the understanding of mechanisms of thiosulfate on organics and nitrogen removal in biological sulfur cycle-based wastewater treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Comparative evaluation of microbial and chemical leaching processes for heavy metal removal from dewatered metal plating sludge

    International Nuclear Information System (INIS)

    Bayat, Belgin; Sari, Bulent

    2010-01-01

    The purpose of the study described in this paper was to evaluate the application of bioleaching technique involving Acidithiobacillus ferrooxidans to recover heavy metals (Zn, Cu, Ni, Pb, Cd and Cr) in dewatered metal plating sludge (with no sulfide or sulfate compounds). The effect of some conditional parameters (i.e. pH, oxidation-reduction potential (ORP), sulfate production) and operational parameters (i.e. pulp density of the sludge and agitation time) were investigated in a 3 l completely mixed batch (CMB) reactor. The metal recovery yields in bioleaching were also compared with chemical leaching of the sludge waste using commercial inorganic acids (sulfuric acids and ferric chloride). The leaching of heavy metals increased with decreasing of pH and increasing of ORP and sulfate production during the bioleaching experiment. Optimum pulp density for bioleaching was observed at 2% (w/v), and leaching efficiency decreased with increasing pulp density in bioleaching experiments. Maximum metal solubilization (97% of Zn, 96% of Cu, 93% of Ni, 84% of Pb, 67% of Cd and 34% of Cr) was achieved at pH 2, solids contents of 2% (w/v), and a reaction temperature of 25 ± 2 deg. C during the bioleaching process. The maximum removal efficiencies of 72% and 79% Zn, 70% and 75% Cu, 69% and 73% Ni, 57% and 70% Pb, 55% and 65% Cd, and 11% and 22% Cr were also attained with the chemical leaching using sulfuric acids and ferric chloride, respectively, at pH 2, solids contents of 2% (w/v), and a reaction temperature of 25 ± 2 deg. C during the acid leaching processes. The rates of metal leaching for bioleaching and chemical leaching are well described by a kinetic equation related to time. Although bioleaching generally requires a longer period of operation compared to chemical leaching, it achieves higher removal efficiency for heavy metals. The efficiency of leaching processes can be arranged in descending order as follows: bioleaching > ferric chloride leaching > sulfuric acid

  6. Comparative evaluation of microbial and chemical leaching processes for heavy metal removal from dewatered metal plating sludge

    Energy Technology Data Exchange (ETDEWEB)

    Bayat, Belgin, E-mail: bbayat@cu.edu.tr [Department of Environmental Engineering, Faculty of Engineering and Architecture, Cukurova University, Balcali, Adana 01330 (Turkey); Sari, Bulent [Department of Environmental Engineering, Faculty of Engineering and Architecture, Cukurova University, Balcali, Adana 01330 (Turkey)

    2010-02-15

    The purpose of the study described in this paper was to evaluate the application of bioleaching technique involving Acidithiobacillus ferrooxidans to recover heavy metals (Zn, Cu, Ni, Pb, Cd and Cr) in dewatered metal plating sludge (with no sulfide or sulfate compounds). The effect of some conditional parameters (i.e. pH, oxidation-reduction potential (ORP), sulfate production) and operational parameters (i.e. pulp density of the sludge and agitation time) were investigated in a 3 l completely mixed batch (CMB) reactor. The metal recovery yields in bioleaching were also compared with chemical leaching of the sludge waste using commercial inorganic acids (sulfuric acids and ferric chloride). The leaching of heavy metals increased with decreasing of pH and increasing of ORP and sulfate production during the bioleaching experiment. Optimum pulp density for bioleaching was observed at 2% (w/v), and leaching efficiency decreased with increasing pulp density in bioleaching experiments. Maximum metal solubilization (97% of Zn, 96% of Cu, 93% of Ni, 84% of Pb, 67% of Cd and 34% of Cr) was achieved at pH 2, solids contents of 2% (w/v), and a reaction temperature of 25 {+-} 2 deg. C during the bioleaching process. The maximum removal efficiencies of 72% and 79% Zn, 70% and 75% Cu, 69% and 73% Ni, 57% and 70% Pb, 55% and 65% Cd, and 11% and 22% Cr were also attained with the chemical leaching using sulfuric acids and ferric chloride, respectively, at pH 2, solids contents of 2% (w/v), and a reaction temperature of 25 {+-} 2 deg. C during the acid leaching processes. The rates of metal leaching for bioleaching and chemical leaching are well described by a kinetic equation related to time. Although bioleaching generally requires a longer period of operation compared to chemical leaching, it achieves higher removal efficiency for heavy metals. The efficiency of leaching processes can be arranged in descending order as follows: bioleaching > ferric chloride leaching > sulfuric

  7. Significant thermal energy reduction in lactic acid production process

    International Nuclear Information System (INIS)

    Mujtaba, Iqbal M.; Edreder, Elmahboub A.; Emtir, Mansour

    2012-01-01

    Lactic acid is widely used as a raw material for the production of biodegradable polymers and in food, chemical and pharmaceutical industries. The global market for lactic acid is expected to reach 259 thousand metric tons by the year 2012. For batch production of lactic acid, the traditional process includes the following steps: (i) esterification of impure lactic acid with methanol in a batch reactor to obtain methyl lactate (ester), (ii) separation of the ester in a batch distillation, (iii) hydrolysis of the ester with water in a batch reactor to produce lactic acid and (iv) separation of lactic acid (in high purity) in a batch distillation. Batch reactive distillation combines the benefit of both batch reactor and batch distillation and enhances conversion and productivity (Taylor and Krishna, 2000 ; Mujtaba and Macchietto, 1997 ). Therefore, the first and the last two steps of the lactic acid production process can be combined together in batch reactive distillation () processes. However, distillation (batch or continuous) is an energy intensive process and consumes large amount of thermal energy (via steam). This paper highlights how significant (over 50%) reduction in thermal energy consumption can be achieved for lactic acid production process by carefully controlling the reflux ratio but without compromising the product specification. In this paper, only the simultaneous hydrolysis of methyl lactate ester and the separation of lactic acid using batch reactive distillation is considered.

  8. Removal of Perfluorooctanoic Acid from Water Using Primitive, Conventional and Novel Carbonaceous Sorbent Materials

    Science.gov (United States)

    Polyfluoroalkyl Substances ( PFAS ), like perfluorooctanoic acid, have been used for the last 50 years in a wide variety of industrial processes and...The Department of Defense (DoD) has used PFAS -based Aqueous Film Forming Foam (AFFF) at fire training facilities and aircraft hangars. These AFFFs have...contaminated approximately 600 sites classified as fire training facilities with PFAS (Huang, 2013). This study focused on testing the most likely

  9. Effect of influent aeration on removal of organic matter from coffee processing wastewater in constructed wetlands.

    Science.gov (United States)

    Rossmann, Maike; Matos, Antonio Teixeira; Abreu, Edgar Carneiro; Silva, Fabyano Fonseca; Borges, Alisson Carraro

    2013-10-15

    The aim of the present study was to evaluate the influence of aeration and vegetation on the removal of organic matter in coffee processing wastewater (CPW) treated in 4 constructed wetlands (CWs), characterized as follows: (i) ryegrass (Lolium multiflorum) cultivated system operating with an aerated influent; (ii) non-cultivated system operating with an aerated influent, (iii) ryegrass cultivated system operating with a non-aerated influent; and (iv) non-cultivated system operating with a non-aerated influent. The lowest average chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of 87, 84 and 73%, respectively, were obtained in the ryegrass cultivated system operating with a non-aerated influent. However, ryegrass cultivation did not influence the removal efficiency of organic matter. Artificial aeration of the CPW, prior to its injection in the CW, did not improve the removal efficiencies of organic matter. On other hand it did contribute to increase the instantaneous rate at which the maximum COD removal efficiency was reached. Although aeration did not result in greater organic matter removal efficiencies, it is important to consider the benefits of aeration on the removal of the other compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Application of natural citric acid sources and their role on arsenic removal from drinking water: a green chemistry approach.

    Science.gov (United States)

    Majumder, Santanu; Nath, Bibhash; Sarkar, Simita; Islam, Sk Mijanul; Bundschuh, Jochen; Chatterjee, Debashis; Hidalgo, Manuela

    2013-11-15

    Solar Oxidation and Removal of Arsenic (SORAS) is a low-cost non-hazardous technique for the removal of arsenic (As) from groundwater. In this study, we tested the efficiency of natural citric acid sources extracted from tomato, lemon and lime to promote SORAS for As removal at the household level. The experiment was conducted in the laboratory using both synthetic solutions and natural groundwater samples collected from As-polluted areas in West Bengal. The role of As/Fe molar ratios and citrate doses on As removal efficiency were checked in synthetic samples. The results demonstrate that tomato juice (as citric acid) was more efficient to remove As from both synthetic (percentage of removal: 78-98%) and natural groundwater (90-97%) samples compared to lemon (61-83% and 79-85%, respectively) and lime (39-69% and 63-70%, respectively) juices. The As/Fe molar ratio and the citrate dose showed an 'optimized central tendency' on As removal. Anti-oxidants, e.g. 'hydroxycinnamates', found in tomato, were shown to have a higher capacity to catalyze SORAS photochemical reactions compared to 'flavanones' found in lemon or lime. The application of this method has several advantages, such as eco- and user- friendliness and affordability at the household level compared to other low-cost techniques. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Process for recovering yttrium and lanthanides from wet-process phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, J.A.; Weterings, C.A.

    1983-06-28

    Process for recovering yttrium and lanthanides from wet-process phosphoric acid by adding a flocculant to the phosphoric acid, separating out the resultant precipitate and then recovering yttrium and lanthanides from the precipitate. Uranium is recovered from the remaining phosphoric acid.

  12. pH-adjustment strategy for volatile fatty acid production from high-strength wastewater for biological nutrient removal.

    Science.gov (United States)

    Xie, Li; Liu, Hui; Chen, Yin-Guang; Zhou, Qi

    2014-01-01

    Volatile fatty acid (VFA) production from three types of high-strength organic wastewater (cassava thin stillage, starch wastewater and yellow-wine processing wastewater) were compared. The results showed that cassava thin stillage was the most suitable substrate, based on its high specific VFA production (0.68 g chemical oxygen demand (COD)/g initial soluble chemical oxygen demand (SCOD)) and yield (0.72 g COD/g SCOD) as well as low nutrient content in the substrate and fermented liquid. The acid fermented cassava thin stillage was evaluated and compared with sodium acetate in a sequencing batch reactor system. Total nitrogen removal efficiency was higher with fermented cassava thin stillage than with the sodium acetate. The effects of pH and a pH-adjustment strategy on VFA production and composition were determined using cassava thin stillage. At an initial pH range of 7-11, a relatively high VFA concentration of about 9 g COD/L was obtained. The specific VFA production (g COD/g initial SCOD) increased from 0.27 to 0.47 to 0.67 at pH 8 and from 0.26 to 0.68 to 0.81 at pH 9 (initial pH, interval pH, and constant pH adjustment, respectively). The dominant VFA species changed significantly with the increasing frequency of the pH adjustment. Further studies will examine the metabolic pathways responsible for VFA composition.

  13. Validity of manganese as a surrogate of heavy metals removal in constructed wetlands treating acidic mine water

    International Nuclear Information System (INIS)

    Royer, E.; Unz, R.F.; Hellier, W.W.

    1998-01-01

    The evaluation of manganese as a surrogate for heavy metal behavior in two wetland treatment systems receiving acidic coal mine drainage in central Pennsylvania was investigated. The use of manganese as an indicator is based on physical/chemical treatment processes quite different from wetland treatment. The treatment systems represented one anoxic, subsurface flow system and one oxic surface flow system. Water quality parameters measured included pH, alkalinity, acidity, and a suite of metals. Correlation and linear regression analysis were used to evaluate the ability of a candidate predictor variable (indicator) to predict heavy metal concentrations and removal. The use of manganese as a predictor of effluent quality proved to be poor in both wetland treatment systems, as evidenced by low linear R 2 values and negative correlations. Zinc emerged as the best predictor of the detectable heavy metals at the anoxic wetland. Zinc exhibited positive strong linear correlations with copper, cobalt, and nickel (R 2 values of 0.843, 0.881, and 0.970, respectively). Effluent pH was a slightly better predictor of effluent copper levels in the anoxic wetland. Iron and cobalt effluent concentrations showed the only strong relationship (R 2 value = 0.778) in the oxic system. The lack of good correlations with manganese strongly challenges its appropriateness as a surrogate for heavy metals in these systems

  14. Biogenic glutamic acid-based resin: Its synthesis and application in the removal of cobalt(II)

    International Nuclear Information System (INIS)

    Jamiu, Zakariyah A.; Saleh, Tawfik A.; Ali, Shaikh A.

    2017-01-01

    Highlights: • A novel resin embedded with metal chelating glutamic acid was synthesized. • The biogenic amino acid residues imparted remarkable efficacy to remove Co(II). • The resin showed excellent ability to remove various metals from wastewater. - Abstract: Inexpensive biogenic glutamic acid has been utilized to synthesize a cross-linked dianionic polyelectrolyte (CDAP) containing metal chelating ligands. Cycloterpolymerization, using azoisobutyronitrile as an initiator, of N,N-diallylglutamic acid hydrochloride, sulfur dioxide and a cross-linker afforded a pH-responsive cross-linked polyzwitterionic acid (CPZA) which upon basification with NaOH was converted into CDAP. The new resin, characterized by a multitude of spectroscopic techniques as well as Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET) analyses, was evaluated for the removal of Co(II) as a model case under different conditions. The adsorption capacity of 137 mg g"−"1 does indeed make the resin as one of the most effective sorbents in recent times. The resin leverages its cheap natural source and ease of regeneration in combination with its high and fast uptake capacities to offer a great promise for wastewater treatment. The resin has demonstrated remarkable efficiency in removing toxic metal ions including arsenic from a wastewater sample.

  15. Biogenic glutamic acid-based resin: Its synthesis and application in the removal of cobalt(II)

    Energy Technology Data Exchange (ETDEWEB)

    Jamiu, Zakariyah A.; Saleh, Tawfik A.; Ali, Shaikh A., E-mail: shaikh@kfupm.edu.sa

    2017-04-05

    Highlights: • A novel resin embedded with metal chelating glutamic acid was synthesized. • The biogenic amino acid residues imparted remarkable efficacy to remove Co(II). • The resin showed excellent ability to remove various metals from wastewater. - Abstract: Inexpensive biogenic glutamic acid has been utilized to synthesize a cross-linked dianionic polyelectrolyte (CDAP) containing metal chelating ligands. Cycloterpolymerization, using azoisobutyronitrile as an initiator, of N,N-diallylglutamic acid hydrochloride, sulfur dioxide and a cross-linker afforded a pH-responsive cross-linked polyzwitterionic acid (CPZA) which upon basification with NaOH was converted into CDAP. The new resin, characterized by a multitude of spectroscopic techniques as well as Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET) analyses, was evaluated for the removal of Co(II) as a model case under different conditions. The adsorption capacity of 137 mg g{sup −1} does indeed make the resin as one of the most effective sorbents in recent times. The resin leverages its cheap natural source and ease of regeneration in combination with its high and fast uptake capacities to offer a great promise for wastewater treatment. The resin has demonstrated remarkable efficiency in removing toxic metal ions including arsenic from a wastewater sample.

  16. A post-processing study on aluminum surface by fiber laser: Removing face milling patterns

    Science.gov (United States)

    Kayahan, Ersin

    2018-05-01

    The face milling process of the metal surface is a well-known machining process of using rotary cutters to remove material from a workpiece. Flat metal surfaces can be produced by a face milling process. However, in practice, visible, traced marks following the motion of points on the cutter's face are usually apparent. In this study, it was shown that milled patterns can be removed by means of 20 W fiber laser on the aluminum surface (AA7075). Experimental results also showed that roughened and hydrophobic surface can be produced with optimized laser parameters. It is a new approach to remove the patterns from the metal surface and can be explained through roughening by re-melting instead of ablation. The new method is a strong candidate to replace sandblasting the metal surface. It is also cheap and environmentally friendly.

  17. Pyrene removal from contaminated soil using electrokinetic process combined with surfactant

    Directory of Open Access Journals (Sweden)

    Seyed Enayat Hashemi

    2015-07-01

    Full Text Available Background: Pyrene is one of the stable polycyclic aromatic hydrocarbons that is considered as an important pollutants, because of extensive distribution in the environment and carcinogenic and mutagenic properties. Among the various treatment techniques, electrokinetic method is an environmental- friendly process for organic and mineral pollutants adsorbed to soil with fine pore size the same as clay and low hydraulic conductivity soils. For improving the efficiency of pyrene removal from soil, soulobilization of pyrene from soil could be used by surfactants. Materials and Methods : In this study, clay soil was selected as model because of the specific properties. Combined method using surfactant and electrokinetic was applied for pyrene removal from soil. Experiments were designed using response surface methodology (RSM, and effect of three variables includes surfactant concentration, voltage and surfactant type were evaluated for pyrene removal from contaminated soil. Results: Pyrene removal using anionic surfactants(SDS and nonionic surfactants(TX100 as a solubilizing agents has high removal efficiency. In the optimum condition with 95% confidence coefficient, utilizing mixed surfactants of sodium dodecyl sulfate and triton X-100 with the same volume, induced of 18.54 volt and 6.53 percent surfactant concentration have 94.6% pyrene removal efficiency. Conclusion:: Results of this study shows that electrokinetic process combined with surfactant as solubilizing agent could be applied as an efficient method for treating the pyrene-contaminated soils.

  18. Comparison of Electrocoagulation and Chemical Coagulation Processes in Removing Reactive red 196 from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Ali Assadi

    2016-06-01

    Full Text Available Background: Conventional chemical coagulation is considered as an old method to dye and COD removal in textile effluent. Electrocoagulation (EC process is a robust method to achieve maximum removal. Methods: This study was designed to compare the result of operational parameters including optimum pH and coagulant concentration for chemical coagulation with ferric chloride and alum also, voltage, electrolysis time, initial pH, and conductivity for EC with iron electrodes to remove reactive red 196 (RR 196. Results: The outcomes show that ferric chloride and alum at optimum concentration were capable of removing dye and COD by 79.63 % and 84.83% and 53% and 55%, respectively. In contrast, EC process removed the dye and COD by 99.98% and 90.4%, respectively. Conclusion: The highest treatment efficiency was obtained by increasing the voltage, electrolysis time, pH and conductivity. Increase initial dye concentration reduces removal efficiency. Ultimately, it could be concluded that EC technology is an efficient procedure for handling of colored industrial wastewaters.

  19. Development Of Chemical Reduction And Air Stripping Processes To Remove Mercury From Wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Dennis G.; Looney, Brian B.; Craig, Robert R.; Thompson, Martha C.; Kmetz, Thomas F.

    2013-07-10

    This study evaluates the removal of mercury from wastewater using chemical reduction and air stripping using a full-scale treatment system at the Savannah River Site. The existing water treatment system utilizes air stripping as the unit operation to remove organic compounds from groundwater that also contains mercury (C ~ 250 ng/L). The baseline air stripping process was ineffective in removing mercury and the water exceeded a proposed limit of 51 ng/L. To test an enhancement to the existing treatment modality a continuous dose of reducing agent was injected for 6-hours at the inlet of the air stripper. This action resulted in the chemical reduction of mercury to Hg(0), a species that is removable with the existing unit operation. During the injection period a 94% decrease in concentration was observed and the effluent satisfied proposed limits. The process was optimized over a 2-day period by sequentially evaluating dose rates ranging from 0.64X to 297X stoichiometry. A minimum dose of 16X stoichiometry was necessary to initiate the reduction reaction that facilitated the mercury removal. Competing electron acceptors likely inhibited the reaction at the lower 1 doses, which prevented removal by air stripping. These results indicate that chemical reduction coupled with air stripping can effectively treat large-volumes of water to emerging part per trillion regulatory standards for mercury.

  20. Mechanism of NOx removal by electron beam process in the presence of scavengers

    International Nuclear Information System (INIS)

    Chmielewski, A.G.; Sun Yongxia; Zimek, Z.; Bulka, S.; Licki, J.

    2002-01-01

    In this study NO x removal efficiency, with/without SO 2 in electron beam flue gas treatment process, was evaluated in the presence of different additives: ammonia, water, and alcohol. It was found that NO x removal efficiency increased by 20% and in the presence of alcohol, more than 70% NO x was oxidized/reduced at 6 kGy for the initial concentration of 500 ppm NO. Humidity and ammonia addition increased the NO x removal efficiency but not more than 10%. Organic products and inorganic products were analyzed by a GC-MS and ion chromatography, respectively. The focus of this paper is on the mechanism that accounts for the increased efficiency in NO x removal

  1. Anammox for ammonia removal from pig manure effluents: Effect of organic matter content on process performance

    DEFF Research Database (Denmark)

    Salces, Beatriz Molinuevo; García, M. C.; Karakashev, Dimitar Borisov

    2009-01-01

    oxidation) diluted with synthetic wastewater. High ammonium removal was achieved, up to 92.1 +/- 4.9% for diluted UASB-post-digested effluent (95 mg COD L-1) and up to 98.5 +/- 0.8% for diluted partially oxidized effluent (121 mg COD L-1). Mass balance clearly showed that an increase in organic loading......The anammox process, under different organic loading rates (COD), was evaluated using a semi-continous UASB reactor at 37 degrees C. Three different substrates were used: initially, synthetic wastewater, and later, two different pig manure effluents (after UASB-post-digestion and after partial...... improved ammonium removal at high organic matter concentration. Up to threshold organic load concentration of 142 mg COD L-1 of UASB-post-digested effluent and 242 mg COD L-1 of partially oxidized effluent, no effect of organic loading on ammonia removal was registered (ammonium removal was above 80...

  2. Effect of acetic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    Science.gov (United States)

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-09-01

    An integrated citric acid-methane fermentation process was proposed to solve the problem of extraction wastewater in citric acid fermentation process. Extraction wastewater was treated by anaerobic digestion and then recycled for the next batch of citric acid fermentation to eliminate wastewater discharge and reduce water resource consumption. Acetic acid as an intermediate product of methane fermentation was present in anaerobic digestion effluent. In this study, the effect of acetic acid on citric acid fermentation was investigated and results showed that lower concentration of acetic acid could promote Aspergillus niger growth and citric acid production. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) staining was used to quantify the activity of A. niger cells, and the results suggested that when acetic acid concentration was above 8 mM at initial pH 4.5, the morphology of A. niger became uneven and the part of the cells' activity was significantly reduced, thereby resulting in deceasing of citric acid production. Effects of acetic acid on citric acid fermentation, as influenced by initial pH and cell number in inocula, were also examined. The result indicated that inhibition by acetic acid increased as initial pH declined and was rarely influenced by cell number in inocula.

  3. BATCH PROCESS INTEGRATION OF APPLYING TECHNOLOGY OF ACID CARMINIC PINCH

    OpenAIRE

    Erazo E., Raymundo; Cárdenas R., Jorge L.; Woolcott H., Juan C.

    2014-01-01

    This work was developed in order to implement the PINCH technology integration batch process for carminic acid. The method used consisted of the application of the concepts of bottle necks total process (OPB) together with part-time models (TAM) and time fractionated! (TSM). The drying operation is identified as the rate limiting step of the process identifying it as an OPB plant capacity. The extraction yield was 95% w / p carminic acid with an energy savings of approximately 60% of the...

  4. Control of instability in nitric acid evaporators for plutonium processing

    International Nuclear Information System (INIS)

    1998-03-01

    Improved control of the nitric acid process evaporators requires the detection of spontaneously unstable operating conditions. This process reduces the volume of contaminated liquid by evaporating nitric acid and concentrating salt residues. If a instability is identified quickly, prompt response can avert distillate contamination. An algorithm applied to the runtime data was evaluated to detect this situation. A snapshot of data from a histogram in the old process control software was captured during the unstable conditions and modeled

  5. Investigation of Cyanide Removal from Aqueous Solution Using Precipitation Process (FeCl3

    Directory of Open Access Journals (Sweden)

    A. Jonidi Jafari

    2013-02-01

    Full Text Available Background and Objectives: Cyanide is a toxic pollutant that is can be discharged from different industries such as iron and steel industry, coal mining and metal plating. Presence of this toxin in water and wastewater is a serious hazard and lead to undesirable effects on both the environment and human. Thus, its concentration control is essential for human health. The aim of this study was investigation of Cyanide Removal from aqueous solution using precipitation process (FeCl3. Material and Methods: This study is an experimental study in lab scale that was carried out in a batch system by jartest. Variations of this study including pH, FeCl3 concentration, reaction time and desired concentration of cyanide were investigated. Data were analyzed using Excel (version 2007 software. Results: The results of this research were showed that Cyanide with initial concentration of 10 mg/l in precipitation process was removed by 40% (conditions pH=90, FeCl3=0.4 g/l and the time 60 minutes. Also, the precipitation process efficiency to cyanide removal decreased of 40 to 23%, by increasing of the initial cyanide concentration of 10 to 15 mg/l. Conclusion: Precipitation process can be considered as a suitable alternative for recovery of cyanide to be re-used. Although, this process has limitations for treat total cyanide to environmental standards level. So, it is better be used in combination with other processes of these contaminants removal.

  6. REMOVAL OF REMAZOL ROSSO RB DYE FROM AQUEOUS EFFLUENTS BY HOMOGENOUS FENTON OXIDATION PROCESSES

    Directory of Open Access Journals (Sweden)

    Carmen Zaharia

    2014-06-01

    Full Text Available The paper presents some data from our laboratory-setup experiments of homogenous oxidative processes with hydrogen peroxide (i.e. advanced Fenton oxidation processes applied for Remazol Rosso RB dye-containing aqueous systems, especially textile effluents. Therefore, some different operating parameters (including pH, concentration of dye, H2O2 and ferrous ions, oxidation time, temperature, stirring regime, among its were tested for determination of the best performance in effluent decoloration and dye removal, meaning the optimal values of each studied parameters for highest decoloration or dye removal.

  7. Tracking acidic pharmaceuticals, caffeine, and triclosan through the wastewater treatment process.

    Science.gov (United States)

    Thomas, Paul M; Foster, Gregory D

    2005-01-01

    Pharmaceuticals are a class of emerging contaminants whose fate in the wastewater treatment process has received increasing attention in past years. Acidic pharmaceuticals (ibuprofen, naproxen, mefenamic acid, ketoprofen, and diclofenac), caffeine, and the antibacterial triclosan were quantified at four different steps of wastewater treatment from three urban wastewater treatment plants. The compounds were extracted from wastewater samples on Waters Oasis hydrophilic-lipophilic balance solid-phase extraction columns, silylated, and analyzed by gas chromatography-mass spectrometry. For the chemicals studied, it was found that the majority of the influent load was removed during secondary treatment (51-99%), yielding expected surface water concentrations of 13 to 56 ng/L.

  8. Optimization of the integrated citric acid-methane fermentation process by air stripping and glucoamylase addition.

    Science.gov (United States)

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Wang, Ke; Tang, Lei; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-03-01

    To solve the problem of extraction wastewater in citric acid industry, an integrated citric acid-methane fermentation process was proposed. In the integrated process, extraction wastewater was treated by mesophilic anaerobic digestion and then reused to make mash for the next batch of citric acid fermentation. In this study, an Aspergillus niger mutant strain exhibiting resistance to high metal ions concentration was used to eliminate the inhibition of 200 mg/L Na(+) and 300 mg/L K(+) in anaerobic digestion effluent (ADE) and citric acid production increased by 25.0 %. Air stripping was used to remove ammonium, alkalinity, and part of metal ions in ADE before making mash. In consequence, citric acid production was significantly improved but still lower by 6.1 % than the control. Results indicated that metal ions in ADE synergistically inhibited the activity of glucoamylase, thus reducing citric acid production. When 130 U/g glucoamylase was added before fermentation, citric acid production was 141.5 g/L, which was even higher than the control (140.4 g/L). This process could completely eliminate extraction wastewater discharge and reduce water resource consumption.

  9. Effects of Humic Acid and Suspended Solids on the Removal of Heavy Metals from Water by Adsorption onto Granular Activated Carbon

    Directory of Open Access Journals (Sweden)

    Danious P. Sounthararajah

    2015-08-01

    Full Text Available Heavy metals constitute some of the most dangerous pollutants of water, as they are toxic to humans, animals, and aquatic organisms. These metals are considered to be of major public health concern and, therefore, need to be removed. Adsorption is a common physico-chemical process used to remove heavy metals. Dissolved organic carbon (DOC and suspended solids (SS are associated pollutants in water systems that can interact with heavy metals during the treatment process. The interactions of DOC and SS during the removal of heavy metals by granular activated carbon were investigated in batch and fixed-bed column experiments. Batch adsorption studies indicated that Langmuir adsorption maxima for Pb, Cu, Zn, Cd, and Ni at pH 6.5 were 11.9, 11.8, 3.3, 2.0, and 1.8 mg/g, respectively. With the addition of humic acid (HA (DOC representative, they were 7.5, 3.7, 3.2, 1.6, and 2.5 mg/g, respectively. In the column experiment, no breakthrough (complete removal was obtained for Pb and Cu, but adding HA provided a breakthrough in removing these metals. For Zn, Cd and Ni, this breakthrough occurred even without HA being added. Adding kaolinite (representative of SS had no effect on Pb and Cu, but it did on the other metals.

  10. Effects of Humic Acid and Suspended Solids on the Removal of Heavy Metals from Water by Adsorption onto Granular Activated Carbon.

    Science.gov (United States)

    Sounthararajah, Danious P; Loganathan, Paripurnanda; Kandasamy, Jaya; Vigneswaran, Saravanamuthu

    2015-08-27

    Heavy metals constitute some of the most dangerous pollutants of water, as they are toxic to humans, animals, and aquatic organisms. These metals are considered to be of major public health concern and, therefore, need to be removed. Adsorption is a common physico-chemical process used to remove heavy metals. Dissolved organic carbon (DOC) and suspended solids (SS) are associated pollutants in water systems that can interact with heavy metals during the treatment process. The interactions of DOC and SS during the removal of heavy metals by granular activated carbon were investigated in batch and fixed-bed column experiments. Batch adsorption studies indicated that Langmuir adsorption maxima for Pb, Cu, Zn, Cd, and Ni at pH 6.5 were 11.9, 11.8, 3.3, 2.0, and 1.8 mg/g, respectively. With the addition of humic acid (HA) (DOC representative), they were 7.5, 3.7, 3.2, 1.6, and 2.5 mg/g, respectively. In the column experiment, no breakthrough (complete removal) was obtained for Pb and Cu, but adding HA provided a breakthrough in removing these metals. For Zn, Cd and Ni, this breakthrough occurred even without HA being added. Adding kaolinite (representative of SS) had no effect on Pb and Cu, but it did on the other metals.

  11. High temperature fluidized bed zero valent iron process for flue gas nitrogen monoxide removal

    International Nuclear Information System (INIS)

    Cheng, C.Y.; Chen, S.S.; Tang, C.H.; Chang, Y.M.; Cheng, H.H.; Liu, H.L.

    2008-01-01

    Nitrogen oxides (NO x ) are generated from a variety of sources, and are critical components of photochemical smog. Zero valent iron (ZVI) has been used to remove NO x in a number of studies. The ZVI process requires no extra chemicals or catalysts. In this study, a fluidized ZVI process for removing NO x from flue gases was proposed. The study examined the effects of temperature, ZVI dosage and influent NO concentrations, and observed the kinetic effects between the fluidized ZVI and NO x . A life cycle analysis of the process was also provided. The parametric analysis was conducted in a series of column studies using a continuous emissions monitoring system. Minimum fluidization velocity equations were provided, and the drag coefficient was determined. Capacities of ZVI for NO removal at different temperatures were calculated. Results of the study suggested that temperature, influent concentrations, and flow rates all influenced kinetic coefficients. Different temperatures resulted in different rates of NO removal. It was concluded that between 673 K and 773 K, almost complete NO removals were achieved. 14 refs., 2 tabs., 9 figs

  12. The effect of peracetic acid on removing calcium hydroxide from the root canals.

    Science.gov (United States)

    Sağsen, Burak; Ustün, Yakup; Aslan, Tuğrul; Canakçi, Burhan Can

    2012-09-01

    The goal of this study was to evaluate the efficiencies of different irrigation solutions in the removal of calcium hydroxide (CH). Forty-eight maxillary central incisor teeth were used. Root canals were prepared with the ProTaper system (Dentsply Maillefer, Baillagues, Switzerland). Five milliliters 2% NaOCl, 5 mL 17% EDTA, and 10 mL saline were used for final irrigation. The canals were filled with CH paste. Specimens were randomly divided into 4 experimental groups (n = 10) according to irrigation protocols. Positive and negative control groups (n = 4) were used. Group 1 used 2.5 mL 17% EDTA, group 2 used 2.5 mL 2.5% NaOCl + 2.5 mL 17% EDTA, group 3 used 2.5 mL 1% peracetic acid (PAA), and group 4 used 2.5 mL 0.5% PAA. The specimens were evaluated with scanning electron microscope analysis and scored. Kruskal-Wallis and Student Newman-Keuls post hoc tests were used for statistical analysis. In the apical thirds, 1% PAA was superior to the other groups (P .05). In the middle thirds, no significant differences were found among the groups (P > .05). In the coronal thirds, 1% PAA was superior to the other groups. There were significant differences among all the other groups (P < .05). According to the findings of the present study, 1% PAA could be recommended for the removal of CH from the root canals. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  13. A sulfuric-lactic acid process for efficient purification of fungal chitosan with intact molecular weight.

    Science.gov (United States)

    Naghdi, Mitra; Zamani, Akram; Karimi, Keikhosro

    2014-02-01

    The most recent method of fungal chitosan purification, i.e., two steps of dilute sulfuric acid treatment, pretreatment of cell wall at room temperature for phosphate removal and extraction of chitosan from the phosphate free cell wall at high temperature, significantly reduces the chitosan molecular weight. This study was aimed at improvement of this method. In the pretreatment step, to choose the best conditions, cell wall of Rhizopus oryzae, containing 9% phosphate, 10% glucosamine, and 21% N-acetyl glucosamine, was treated with sulfuric, lactic, acetic, nitric, or hydrochloric acid, at room temperature. Sulfuric acid showed the best performance in phosphate removal (90%) and cell wall recovery (89%). To avoid depolymerisation of chitosan, hot sulfuric acid extraction was replaced with lactic acid treatment at room temperature, and a pure fungal chitosan was obtained (0.12 g/g cell wall). Similar pretreatment and extraction processes were conducted on pure shrimp chitosan and resulted in a chitosan recovery of higher than 87% while the reduction of chitosan viscosity was less than 15%. Therefore, the sulfuric-lactic acid method purified the fungal chitosan without significant molecular weight manipulation. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Reclamation of heavy metals from contaminated soil using organic acid liquid generated from food waste: removal of Cd, Cu, and Zn, and soil fertility improvement.

    Science.gov (United States)

    Dai, Shijin; Li, Yang; Zhou, Tao; Zhao, Youcai

    2017-06-01

    Food waste fermentation generates complicated organic and acidic liquids with low pH. In this work, it was found that an organic acid liquid with pH 3.28 and volatile low-molecular-weight organic acid (VLMWOA) content of 5.2 g/L could be produced from food wastes after 9-day fermentation. When the liquid-to-solid ratio was 50:1, temperature was 40 °C, and contact time was 0.5-1 day, 92.9, 78.8, and 52.2% of the Cd, Cu, and Zn in the contaminated soil could be washed out using the fermented food waste liquid, respectively. The water-soluble, acid-soluble, and partly reducible heavy metal fractions can be removed after 0.5-day contact time, which was more effective than that using commercially available VLMWOAs (29-72% removal), as the former contained microorganisms and adequate amounts of nutrients (nitrogen, phosphorous, and exchangeable Na, K, and Ca) which favored the washing process of heavy metals. It is thus suggested that the organic acid fractions from food waste has a considerable potential for reclaiming contaminated soil while improving soil fertility.

  15. Development of practical decontamination process for the removal of uranium from gravel.

    Science.gov (United States)

    Kim, Ilgook; Kim, Gye-Nam; Kim, Seung-Soo; Choi, Jong-Won

    2018-01-01

    In this study, a practical decontamination process was developed to remove uranium from gravel using a soil washing method. The effects of critical parameters including particle size, H 2 SO 4 concentration, temperature, and reaction time on uranium removal were evaluated. The optimal condition for two-stage washing of gravel was found to be particle size of 1-2 mm, 1.0 M H 2 SO 4 , temperature of 60°C, and reaction time of 3 h, which satisfied the required uranium concentration for self-disposal. Furthermore, most of the extracted uranium was removed from the waste solution by precipitation, implying that the treated solution can be reused as washing solution. These results clearly demonstrated that our proposed process can be indeed a practical technique to decontaminate uranium-polluted gravel.

  16. The removal of mercury from solid mixed waste using chemical leaching processes

    International Nuclear Information System (INIS)

    Gates, D.D.; Chao, K.K.; Cameron, P.A.

    1995-07-01

    The focus of this research was to evaluate chemical leaching as a technique to treat soils, sediments, and glass contaminated with either elemental mercury or a combination of several mercury species. Potassium iodide/iodine solutions were investigated as chemical leaching agents for contaminated soils and sediments. Clean, synthetic soil material and surrogate storm sewer sediments contaminated with mercury were treated with KI/I 2 solutions. It was observed that these leaching solutions could reduce the mercury concentration in soil and sediments by 99.8%. Evaluation of selected posttreatment sediment samples revealed that leachable mercury levels in the treated solids exceeded RCRA requirements. The results of these studies suggest that KI/I 2 leaching is a treatment process that can be used to remove large quantities of mercury from contaminated soils and sediments and may be the only treatment required if treatment goals are established on Hg residual concentrations in solid matrices. Fluorescent bulbs were used to simulate mercury contaminated glass mixed waste. To achieve mercury contamination levels similar to those found in larger bulbs such as those used in DOE facilities a small amount of Hg was added to the crushed bulbs. The most effective agents for leaching mercury from the crushed fluorescent bulbs were KI/I 2 , NaOCl, and NaBr + acid. Radionuclide surrogates were added to both the EPA synthetic soil material and the crushed fluorescent bulbs to determine the fate of radionuclides following chemical leaching with the leaching agents determined to be the most promising. These experiments revealed that although over 98% of the dosed mercury solubilized and was found in the leaching solution, no Cerium was measured in the posttreatment leaching solution. This finding suggest that Uranium, for which Ce was used as a surrogate, would not solubilize during leaching of mercury contaminated soil or glass

  17. Vertical eddy diffusion as a key mechanism for removing perfluorooctanoic acid (PFOA) from the global surface oceans

    NARCIS (Netherlands)

    Lohmann, R.; Jurado Cojo, E.|info:eu-repo/dai/nl/325788227; Dijkstra, H.A.|info:eu-repo/dai/nl/073504467; Dachs, J.

    2013-01-01

    Here we estimate the importance of vertical eddy diffusion in removing perfluorooctanoic acid (PFOA) from the surface Ocean and assess its importance as a global sink. Measured water column profiles of PFOA were reproduced by assuming that vertical eddy diffusion in a 3-layer ocean model is the sole

  18. Impact of humic/fulvic acid on the removal of heavy metals from aqueous solutions using nanomaterials: a review.

    Science.gov (United States)

    Tang, Wang-Wang; Zeng, Guang-Ming; Gong, Ji-Lai; Liang, Jie; Xu, Piao; Zhang, Chang; Huang, Bin-Bin

    2014-01-15

    Nowadays nanomaterials have been widely used to remove heavy metals from water/wastewater due to their large surface area and high reactivity. Humic acid (HA) and fulvic acid (FA) exist ubiquitously in aquatic environments and have a variety of functional groups which allow them to complex with metal ions and interact with nanomaterials. These interactions can not only alter the environmental behavior of nanomaterials, but also influence the removal and transportation of heavy metals by nanomaterials. Thus, the interactions and the underlying mechanisms involved warrant specific investigations. This review outlined the effects of HA/FA on the removal of heavy metals from aqueous solutions by various nanomaterials, mainly including carbon-based nanomaterials, iron-based nanomaterials and photocatalytic nanomaterials. Moreover, mechanisms involved in the interactions were discussed and potential environmental implications of HA/FA to nanomaterials and heavy metals were evaluated. © 2013.

  19. Arsenic removal in water by means of coagulation-flocculation processes

    International Nuclear Information System (INIS)

    Franco, M. F.; Carro P, M. E.

    2014-01-01

    Arsenic and arsenical compounds are considered as carcinogenic and risky for humans according to epidemiological evidence related with the ingestion of arsenical water during a long period. In many places the only source of drinking water contains arsenic and, therefore, removal strategies have to be investigated. This work shows experimental results of coagulation-flocculation processes implemented to evaluate the efficiency in the removal of arsenic from drinking water. The main objectives include the evaluation of the relevant aspect that controls the removal efficiency. Experimental tests were performed with coagulant concentrations from 5 to 500 mg/L, solid particle concentrations from 0 to 6000 mg/L, and initial arsenic concentrations from 0.5 to 5 mg/L. These variables were simultaneously varied in more than 100 experiments. The efficiency in remediation ranged from 0% to 95%. Removal efficiency near 95% was obtained when using ferric chloride as coagulant, and was close to 80% when using aluminium sulfate as coagulant in arsenate solutions. The remediation efficiency decreased significantly when the ferric chloride concentration was higher than 50 mg/L in relation to the obtained results for aluminum sulfate for different type and concentration of soil particles. The highest removal efficiency were obtained at ph between 3 and 5 in oxidized solutions. Obtained results simulated by means of multiple linear regression analysis (R>0.90) allow determining that the main parameters that control the removal of arsenic from drinking water are coagulant concentration, ph, and solid particles concentration. Conversely, particle mineralogy and coagulant type have less significant effect on the removal by means of coagulation-flocculation mechanisms. Obtained results are relevant for the removal of As in water treatment plants as well as for the development of small scale filters. The samples were studied by scanning electron microscopy and energy dispersive X

  20. Establishment and assessment of an integrated citric acid-methane production process.

    Science.gov (United States)

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Bao, Jia-Wei; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the problem of extraction wastewater in citric acid industrial production, an improved integrated citric acid-methane production process was established in this study. Extraction wastewater was treated by anaerobic digestion and then the anaerobic digestion effluent (ADE) was stripped by air to remove ammonia. Followed by solid-liquid separation to remove metal ion precipitation, the supernatant was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. 130U/g glucoamylase was added to medium after inoculation and the recycling process performed for 10 batches. Fermentation time decreased by 20% in recycling and the average citric acid production (2nd-10th) was 145.9±3.4g/L, only 2.5% lower than that with tap water (149.6g/L). The average methane production was 292.3±25.1mL/g CODremoved and stable in operation. Excessive Na(+) concentration in ADE was confirmed to be the major challenge for the proposed process. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Characterization of commercial ceramic adsorbents and their application on naphthenic acids removal of petroleum distillates; Caracterizacao de adsorventes ceramicos comerciais e sua aplicacao na remocao de acidos naftenicos de destilados de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, J.P.; Senna, L.F. de; Lago, D.C.B. do; Silva Junior, P.F. da; Figueiredo, M.A.G. de; Dias, E.G. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)], e-mail: julia_psi@yahoo.com.br; Chiaro, S.S.X. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2006-07-01

    One denominates 'naphthenic acids' to the mixture of carboxylic acids that is present in petroleum oil, and is directly responsible for its acidity and corrosiveness in liquid phase during the refine process. These acids are also presents in distilled fraction of petroleum, causing several problems in final products quality. A possible way to remove them from petroleum distilled fractions is the adsorption in porous materials. However, the published results indicate that ion exchange resins would be the best adsorbents for this process, which would probably increase its cost. In this work, two commercial adsorbents (clay and activated alumina) were characterized by a set of physical-chemistry techniques and evaluated concerning their capacity of removing naphthenic acids from a light petroleum fraction. It was also verified the influence of a previous thermal treatment to the adsorption in their physical-chemistry characteristics and its properties. (author)

  2. Removal of humic acid by a new type of electrical hollow-fiber microfiltration (E-HFMF)

    Science.gov (United States)

    Shang, Ran; Deng, Hui-ping; Hu, Jing-yi

    2010-11-01

    Low pressure membrane filtration, such as microfiltration, was widely used in the field of drinking water purification in the past few decades. Traditional microfiltration membranes are not efficient enough in the removal of natural organic matters (NOM) from raw water. Moreover, they tend to be fouled by the NOM and the filtration age of the membranes is thus shrinked. To tackle these problems, a new type of electrical hollow-fiber microfiltration module (E-HFMF) was designed. In the E-HFMF module, the hollow-fiber microfiltration membranes were placed into the radialized electrical field which functioned from the centre to the exterior of the cylindrical cavity. The main goal of the present study was to evaluate the efficiency of E-HFMF to remove the humic acid (HA, one of the main components of NOM). According to the parallel tests compared with the traditional microfiltration, the removal rate of humic acid was raised to 70%˜85% in terms of UV-254 and to 60%˜75% in terms of DOC when filtrating with the E-HFMF, while the removal rates of humic acid were 10%˜20% and 1%˜10% respectively when filtrating with the traditional microfiltration. The negative charged humic acid moved to the anode because of the electrophoresis, so few humic acid could be able to permeate through the membrane. The electrophoresis mobility of the humic acid permeating through the traditional microfiltration decreased by 19%, while the same index from the E-HFMF decreased by 75%. This indicated that the electrophoresis played a significant role on removing the humic acid. According to the gel permeate chromatograph analysis, humic acid aggregated in an electric field and thus forms loose and permeable cake layer on the membrane surface, which also relieved membrane fouling. Meanwhile, the negative charged humic acid migrating to the anode at the center minimized the deposition onto the membrane surface, and eliminated the membrane fouling as a result. During the E-HFMF filtration, the

  3. Application of Acid Cracking and Fenton Processes inTreating Olive Mill Wastewater

    Directory of Open Access Journals (Sweden)

    Majid Aliabadi

    2006-03-01

    Full Text Available In recent years, the growth in the industries of olive oil extraction has brought about a number of environmental problems. The waste water resulting from olive oil extraction can not be naturally degraded due to the presence of phenol, volatile fatty acids, catchin, and other recalcitrants.In recent years advanced oxidation processes based on hydroxyl radical are paid special attention by scientific, research and industrial centers to degrade the pollutants. In this study, a combination of acid cracking and advanced oxidation process in terms of Fenton process have been studied. Results showed that acid cracking can remove 97, 47, 30, 63 and 57 percent of Turbidity, COD, Total Phenols, Color and Aromaticity, respectively. Fenton process in pH=3 at optimal conditions can remove 57, 97, 18 and 32 percent of COD, Total Phenols, Color and Aromaticity, respectively. Necessary time of reaction was 4 hrs and optimum concentration of H2O2 and Fe2+ ions was determined 0. 5 M and 0.02 M, respectively. Increasing temperature in the range of 25-35°C and type of iron used(ferric or ferrous has no considerable effect in  the efficiency of the process.

  4. Chromium (Cr+6 Removal from Aqueous Environments by Electrocoagulation Process Using Aluminum Electrodes

    Directory of Open Access Journals (Sweden)

    Amir Hossein Mahvi

    2007-06-01

    Full Text Available The performance of electrocoagulation, with aluminum sacrificial anode, has been investigated. for removal of Cr (VI, Several working parameters, such as pollutant concentration, pH, electrical potential, COD, turbidity, and reaction time were studied in an attempt to achieve higher removal efficiency levels. Solutions of varying chromium concentrations (5-50-500 ppm were prepared. To follow the progress of the treatment, samples of 25ml were taken at 20 min intervals for up to 1 h and then filtered (0.45 μ to eliminate sludge formed during electrolysis. The pH of the initial solution was also varied to study its effects on chromium removal efficiency. Results obtained with synthetic wastewater revealed that the most effective chromium removal efficiency could be achieved when a constant pH level of 3 was maintained. In addition, increased electrical potential, within the range of 20-40V, enhanced treatment rate without affecting the charge loading, but required reduced metal ion concentrations to below admissible standard levels. The process was successfully applied to the treatment of an electroplating wastewater where an effective reduction of Cr (VI concentration below standard limits was obtained just after 20-60 min. The method was found to be highly efficient and relatively fast compared to conventional techniques. Thus, it may be concluded that electrocoagulation process has the potential to be utilized for the cost-effective removal of heavy metals from water and wastewater.

  5. Application of Electrochemical Process in Removal of Heavy Metals from Landfill Leachate

    Directory of Open Access Journals (Sweden)

    Mostafaii Gh.1 PhD,

    2016-08-01

    Full Text Available Aims Municipal landfill leachate contains high concentrations of heavy metals, organics, ammonia. The efficeincy of electrochemically removal of heavy metals from landfill leachate was studied. Materials & Methods The leachate was obtained from Kahrizak landfill in south of Tehran. The experiments were carried out by batch process. The 2liter batch reactor was made of glass. There were eight anodes and cathodes electrodes. The electrodes were placed vertically parallel to each other and they were connected to a digital DC power supply. The pH and conductivity were adjusted to a desirable value using NaOH or H2SO4, and NaCl. All the runs were performed at constant temperature of 25°C. In each run, 1.5liter of the leachate was placed into the electrolytic cell. Samples were extracted every 10min and then filtered through a mixed cellulose acetate membrane (0.42μm. The amount of Lead, Zinc and Nickel removal was measured at pH=7 and in current density of 0.5, 0.75, and 1A. Findings When current density and time reaction increased, removal efficiency of heavy metals such as Lead, Zinc and Nickel increased. At initial pH=7, density 1A and reaction time= 60min, Lead, Nickel and Zinc were removed up to 86, 93 and 95%, respectively. Conclusion Electrochemical process can be proposed as a suitable technique to remove heavy metal from landfill leachate.

  6. Start-Up and Aeration Strategies for a Completely Autotrophic Nitrogen Removal Process in an SBR

    Directory of Open Access Journals (Sweden)

    Xiaoling Zhang

    2017-01-01

    Full Text Available The start-up and performance of the completely autotrophic nitrogen removal via nitrite (CANON process were examined in a sequencing batch reactor (SBR with intermittent aeration. Initially, partial nitrification was established, and then the DO concentration was lowered further, surplus water in the SBR with high nitrite was replaced with tap water, and continuous aeration mode was turned into intermittent aeration mode, while the removal of total nitrogen was still weak. However, the total nitrogen (TN removal efficiency and nitrogen removal loading reached 83.07% and 0.422 kgN/(m3·d, respectively, 14 days after inoculating 0.15 g of CANON biofilm biomass into the SBR. The aggregates formed in SBR were the mixture of activated sludge and granular sludge; the volume ratio of floc and granular sludge was 7 : 3. DNA analysis showed that Planctomycetes-like anammox bacteria and Nitrosomonas-like aerobic ammonium oxidization bacteria were dominant bacteria in the reactor. The influence of aeration strategies on CANON process was investigated using batch tests. The result showed that the strategy of alternating aeration (1 h and nonaeration (1 h was optimum, which can obtain almost the same TN removal efficiency as continuous aeration while reducing the energy consumption, inhibiting the activity of NOB, and enhancing the activity of AAOB.

  7. Effects of alternating and direct current in electrocoagulation process on the removal of cadmium from water

    International Nuclear Information System (INIS)

    Vasudevan, Subramanyan; Lakshmi, Jothinathan; Sozhan, Ganapathy

    2011-01-01

    Highlights: → Very high removal efficiency of cadmium was achieved by electrocoagulation. → Alternating current (AC) avoids oxide layer and corrosion on anode surface. → Good current transfer between anode and cathode results more removal efficiency. → Compact treatment facility and complete automation. → Aluminum alloy anode prevents residual aluminum in treated water. - Abstract: In practice, direct current (DC) is used in an electrocoagulation processes. In this case, an impermeable oxide layer may form on the cathode as well as corrosion formation on the anode due to oxidation. This prevents the effective current transfer between the anode and cathode, so the efficiency of electrocoagulation processes declines. These disadvantages of DC have been diminished by adopting alternating current (AC) in electrocoagulation processes. The main objective of this study is to investigate the effects of AC and DC on the removal of cadmium from water using aluminum alloy as anode and cathode. The results showed that the removal efficiency of 97.5 and 96.2% with the energy consumption of 0.454 and 1.002 kWh kl -1 was achieved at a current density of 0.2 A/dm 2 and pH of 7.0 using aluminum alloy as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of cadmium was preferably fitting Langmuir adsorption isotherm, the adsorption process follows second order kinetics and the temperature studies showed that adsorption was exothermic and spontaneous in nature.

  8. 75 FR 71353 - Office of the Attorney General; Certification Process for State Capital Counsel Systems; Removal...

    Science.gov (United States)

    2010-11-23

    ... the Attorney General; Certification Process for State Capital Counsel Systems; Removal of Final Rule... only if the Attorney General has certified ``that [the] State has established a mechanism for providing... State to qualify for the special habeas procedures, the Attorney General must determine that ``the State...

  9. 75 FR 29217 - Office of the Attorney General; Certification Process for State Capital Counsel Systems; Removal...

    Science.gov (United States)

    2010-05-25

    ... Office of the Attorney General; Certification Process for State Capital Counsel Systems; Removal of Final Rule AGENCY: Office of the Attorney General, Department of Justice. ACTION: Notice of proposed... the Attorney General has certified ``that [the] State has established a mechanism for providing...

  10. Effects of alternating and direct current in electrocoagulation process on the removal of cadmium from water

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Subramanyan, E-mail: vasudevan65@gmail.com [CSIR-Central Electrochemical Research Institute, Karaikudi 630 006 (India); Lakshmi, Jothinathan; Sozhan, Ganapathy [CSIR-Central Electrochemical Research Institute, Karaikudi 630 006 (India)

    2011-08-15

    Highlights: {yields} Very high removal efficiency of cadmium was achieved by electrocoagulation. {yields} Alternating current (AC) avoids oxide layer and corrosion on anode surface. {yields} Good current transfer between anode and cathode results more removal efficiency. {yields} Compact treatment facility and complete automation. {yields} Aluminum alloy anode prevents residual aluminum in treated water. - Abstract: In practice, direct current (DC) is used in an electrocoagulation processes. In this case, an impermeable oxide layer may form on the cathode as well as corrosion formation on the anode due to oxidation. This prevents the effective current transfer between the anode and cathode, so the efficiency of electrocoagulation processes declines. These disadvantages of DC have been diminished by adopting alternating current (AC) in electrocoagulation processes. The main objective of this study is to investigate the effects of AC and DC on the removal of cadmium from water using aluminum alloy as anode and cathode. The results showed that the removal efficiency of 97.5 and 96.2% with the energy consumption of 0.454 and 1.002 kWh kl{sup -1} was achieved at a current density of 0.2 A/dm{sup 2} and pH of 7.0 using aluminum alloy as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of cadmium was preferably fitting Langmuir adsorption isotherm, the adsorption process follows second order kinetics and the temperature studies showed that adsorption was exothermic and spontaneous in nature.

  11. In-situ product removal from fermentations by membrane extraction: conceptual process design and economics

    NARCIS (Netherlands)

    Heerema, L.; Roelands, C.P.M.; Goetheer, E.L.V.; Verdoes, D.; Keurentjes, J.

    2011-01-01

    This paper describes a conceptual process design for the production of the model component phenol by a recombinant strain of the micro-organism Pseudomonas putida S12. The (bio)production of the inhibiting component phenol in a bioreactor is combined with direct product removal by membrane

  12. Computer Aided Synthesis of Innovative Processes: Renewable Adipic Acid Production

    DEFF Research Database (Denmark)

    Rosengarta, Alessandro; Bertran, Maria-Ona; Manenti, Flavio

    2017-01-01

    A promising biotechnological route for the production of adipic acid from renewables has been evaluated, applying a systematic methodology for process network synthesis and optimization. The method allows organizing in a structured database the available knowledge from different sources (prelimin...

  13. Removal of acid blue 062 on aqueous solution using calcinated colemanite ore waste

    Energy Technology Data Exchange (ETDEWEB)

    Atar, Necip [Department of Chemistry, Faculty of Arts and Science, University of Dumlupinar, Kuetahya (Turkey); Olgun, Asim [Department of Chemistry, Faculty of Arts and Science, University of Dumlupinar, Kuetahya (Turkey)]. E-mail: aolgun@dumlupinar.edu.tr

    2007-07-19

    Colemanite ore waste (CW) has been employed as adsorbent for the removal of acid blue 062 anionic dye (AB 062) from aqueous solution. The adsorption of AB 062 onto CW was examined with respect to contact time, calcination temperature, particle size, pH, adsorbent dosage and temperature. The physical and chemical properties of the CW, such as particle sizes and calcinations temperature, play important roles in dye adsorption. The dye adsorption largely depends on the initial pH of the solution with maximum uptake occurring at pH 1.Three simplified kinetics models, namely, pseudo-first order, pseudo-second order, and intraparticle diffusion models were tested to investigate the adsorption mechanisms. The kinetic adsorption of AB 062 on CW follows a pseudo-second order equation. The adsorption data have been analyzed using Langmuir and Freundlich isotherms. The results indicate that the Langmuir model provides the best correlation of the experimental data. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy and entropy of the adsorption of dye onto CW.

  14. Removal of acid blue 062 on aqueous solution using calcinated colemanite ore waste

    International Nuclear Information System (INIS)

    Atar, Necip; Olgun, Asim

    2007-01-01

    Colemanite ore waste (CW) has been employed as adsorbent for the removal of acid blue 062 anionic dye (AB 062) from aqueous solution. The adsorption of AB 062 onto CW was examined with respect to contact time, calcination temperature, particle size, pH, adsorbent dosage and temperature. The physical and chemical properties of the CW, such as particle sizes and calcinations temperature, play important roles in dye adsorption. The dye adsorption largely depends on the initial pH of the solution with maximum uptake occurring at pH 1.Three simplified kinetics models, namely, pseudo-first order, pseudo-second order, and intraparticle diffusion models were tested to investigate the adsorption mechanisms. The kinetic adsorption of AB 062 on CW follows a pseudo-second order equation. The adsorption data have been analyzed using Langmuir and Freundlich isotherms. The results indicate that the Langmuir model provides the best correlation of the experimental data. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy and entropy of the adsorption of dye onto CW

  15. Application of molecularly imprinted polymers to selective removal of clofibric acid from water.

    Science.gov (United States)

    Dai, Chaomeng; Zhang, Juan; Zhang, Yalei; Zhou, Xuefei; Liu, Shuguang

    2013-01-01

    A new molecularly imprinted polymer (MIP) adsorbent for clofibric acid (CA) was prepared by a non-covalent protocol. Characterization of the obtained MIP was achieved by scanning electron microscopy (SEM) and nitrogen sorption. Sorption experimental results showed that the MIP had excellent binding affinity for CA and the adsorption of CA by MIP was well described by pseudo-second-order model. Scatchard plot analysis revealed that two classes of binding sites were formed in the MIP with dissociation constants of 7.52 ± 0.46 mg L(-1) and 114 ± 4.2 mg L(-1), respectively. The selectivity of MIP demonstrated higher affinity for CA over competitive compound than that of non-imprinted polymers (NIP). The MIP synthesized was used to remove CA from spiked surface water and exhibited significant binding affinity towards CA in the presence of total dissolved solids (TDS). In addition, MIP reusability was demonstrated for at least 12 repeated cycles without significant loss in performance.

  16. Application of molecularly imprinted polymers to selective removal of clofibric acid from water.

    Directory of Open Access Journals (Sweden)

    Chaomeng Dai

    Full Text Available A new molecularly imprinted polymer (MIP adsorbent for clofibric acid (CA was prepared by a non-covalent protocol. Characterization of the obtained MIP was achieved by scanning electron microscopy (SEM and nitrogen sorption. Sorption experimental results showed that the MIP had excellent binding affinity for CA and the adsorption of CA by MIP was well described by pseudo-second-order model. Scatchard plot analysis revealed that two classes of binding sites were formed in the MIP with dissociation constants of 7.52 ± 0.46 mg L(-1 and 114 ± 4.2 mg L(-1, respectively. The selectivity of MIP demonstrated higher affinity for CA over competitive compound than that of non-imprinted polymers (NIP. The MIP synthesized was used to remove CA from spiked surface water and exhibited significant binding affinity towards CA in the presence of total dissolved solids (TDS. In addition, MIP reusability was demonstrated for at least 12 repeated cycles without significant loss in performance.

  17. Novel cost effective full scale mussel shell bioreactors for metal removal and acid neutralization.

    Science.gov (United States)

    DiLoreto, Z A; Weber, P A; Olds, W; Pope, J; Trumm, D; Chaganti, S R; Heath, D D; Weisener, C G

    2016-12-01

    Acid mine drainage (AMD) impacted waters are a worldwide concern for the mining industry and countries dealing with this issue; both active and passive technologies are employed for the treatment of such waters. Mussel shell bioreactors (MSB) represent a passive technology that utilizes waste from the shellfish industry as a novel substrate. The aim of this study is to provide insight into the biogeochemical dynamics of a novel full scale MSB for AMD treatment. A combination of water quality data, targeted geochemical extractions, and metagenomic analyses were used to evaluate MSB performance. The MSB raised the effluent pH from 3.4 to 8.3 while removing up to ∼99% of the dissolved Al, and Fe and >90% Ni, Tl, and Zn. A geochemical gradient was observed progressing from oxidized to reduced conditions with depth. The redox conditions helped define the microbial consortium that consists of a specialized niche of organisms that influence elemental cycling (i.e. complex Fe and S cycling). MSB technology represents an economic and effective means of full scale, passive AMD treatment that is an attractive alternative for developing economies due to its low cost and ease of implementation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Removal of Mn(II) from the acid mine wastewaters using coal fired bottom ash

    Science.gov (United States)

    Mahidin, M.; Sulaiman, T. N.; Muslim, A.; Gani, A.

    2017-06-01

    Acid mine wastewater (AMW), the wastewater from mining activities which has low pH about 3-5 and contains hazardous heavy metals such as Cu, Fe, Mn, Zn, Pb, etc. Those heavy metals pollution is of prime concern from the environmental view point. Among the heavy metals, Mn occupies the third position in the AMW from one the iron ore mining company in Aceh, Indonesia. In this study, the possibility use of bottom ash from coal fired boiler of steam power plants for the removal of Mn(II) in AMW has been investigated. Experimental has been conducted as follows. Activation of bottom ash was done both by physical and chemical treatments through heating at 270 °C and washing with NaOH activator 0.5 and 1 M. Adsorption test contains two parts observation; preliminary and primary experiments. Preliminary study is addressed to select the best condition of three independent variables i.e.: pH of AMW (3 & 7), bottom ash particle size (40, 60 & 100 mesh) and initial Mn(II) concentrations (100 & 600 mg/l). AMW used was synthetics wastewater. It was found that the best value for NaOH is 1 M, pH is 7, particle size is 100 meshes and initial Mn(II) concentration is 600 mg/l from the adsorption efficiency point of view. The maximum adsorption capacity (q e) is 63.7 mg/g with the efficiency of 85%.

  19. Removal of uranyl ions by p-hexasulfonated calyx[6]arene acid

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, Ioana-Carmen [R and D National Institute for Metals and Radioactive Resources–ICPMRR, B-dul Carol I No.70, Sector 2, Bucharest 020917 (Romania); Petru, Filip [“C.D. Nenitescu” Institute of Organic Chemistry, Splaiul Independentei 202B, Sector 6, Bucharest 71141 (Romania); Humelnicu, Ionel [“Al.I. Cuza” University of Iasi, The Faculty of Chemistry, Bd. Carol-I No. 11, Iasi 700506 (Romania); Mateescu, Marina [National R and D Institute for Chemistry and Petrochemistry, Splaiul Independenţei No. 202, Bucharest 060021 (Romania); Militaru, Ecaterina [R and D National Institute for Metals and Radioactive Resources–ICPMRR, B-dul Carol I No.70, Sector 2, Bucharest 020917 (Romania); Humelnicu, Doina, E-mail: doinah@uaic.ro [“Al.I. Cuza” University of Iasi, The Faculty of Chemistry, Bd. Carol-I No. 11, Iasi 700506 (Romania)

    2014-10-15

    Radioactive pollution is a significant threat for the people’s health. Therefore highly effective radioactive decontamination methods are required. Ion exchange, biotechnologies and phytoremediation in constructed wetlands have been used as radioactive decontamination technologies for uranium contaminated soil and water remediation. Recently, beside those classical methods the calix[n]arenic derivatives’ utilization as radioactive decontaminators has jogged attention. The present work aims to present the preliminary research results of uranyl ion sorption studies on the p-hexasulfonated calyx[6]arenic acid. The effect of temperature, contact time, sorbent amount and uranyl concentration variation on sorption efficiency was investigated. Isotherm models revealed that the sorption process fit better Langmuir isotherm.

  20. Development of a model describing virus removal process in an activated sludge basin

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T.; Shiragami, N. Unno, H. [Tokyo Institute of Technology, Tokyo (Japan)

    1995-06-20

    The virus removal process from the liquid phase in an activated sludge basin possibly consists of physicochemical processes, such as adsorption onto sludge flocs, biological processes such as microbial predating and inactivation by virucidal components excreted by microbes. To describe properly the virus behavior in an activated sludge basin, a simple model is proposed based on the experimental data obtained using a poliovirus type 1. A three-compartments model, which include the virus in the liquid phase and in the peripheral and inner regions of sludge flocs is employed. By using the model, the Virus removal process was successfully simulated to highlight the implication of its distribution in the activated sludge basin. 17 refs., 8 figs.

  1. The effect of amino acids on lipid production and nutrient removal by Rhodotorula glutinis cultivation in starch wastewater.

    Science.gov (United States)

    Liu, Meng; Zhang, Xu; Tan, Tianwei

    2016-10-01

    In this paper, the components of amino acids in mixed starch wastewater (corn steep water/corn gluten water=1/3, v/v) were analyzed by GC-MS. Effects of amino acids on lipid production by Rhodotorula glutinis and COD removal were studied. The results showed that mixed starch wastewater contained 9 kinds of amino acids and these amino acids significantly improved the biomass (13.63g/L), lipid yield (2.48g/L) and COD removal compared to the basic medium (6.23g/L and 1.56g/L). In a 5L fermentor containing mixed starch wastewater as substrate to culture R. glutinis, the maximum biomass, lipid content and lipid yield reached 26.38g/L, 28.90% and 7.62g/L, with the associated removal rates of COD, TN and TP reaching 77.41%, 69.12% and 73.85%, respectively. The results revealed a promising approach for lipid production with using amino acids present in starch wastewater as an alternative nitrogen source. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Humic Acid Degradation via Solar Photo-Fenton Process in Aqueous Environment

    Directory of Open Access Journals (Sweden)

    Seyed Ali Sajjadi

    2015-08-01

    Full Text Available Control of mutagenic and carcinogenic disinfection by-products, particularly Trihalomethanes (THMs and Halo Acetic Acids (HAAs in water treatment process is critical, due to their adverse effects on human health. Generally, reducing the toxicity of these by-products hinges on prior removal of the precursor materials, such as Humic Acid (HA in drinking water. This study was conducted to investigate the role of some parameters that could affect the removal of HA, including HA (5 and 10 ppm and H2O2 (20, 40, 60, and 80 ppm initial concentrations, Iron (II, sulfate heptahydrate dosage (4, 8, 12, and 16 ppm, pH (2, 3, 4 and 5, Oxidation time (5, 10, 15 and 30 min, and Sunlight levels (322±13 kWm-2. To accelerate the process of HA removal, the Solar Photo-Fenton (SPF process was employed by direct irradiation of converged sunlight in a Parabolic Trough Collectors (PTC, with 3m2 effective area. HA levels were measured via quantifying Dissolved Organic Carbon (DOC concentrations by means of a TOC Analyzer method. The results showed that the SPF process is under control of the Fe & H2O2 ratio, the Fe2+ dosage and especially the pH quantity. In optimal condition, (pH: 4, oxidation time: 30min, initial HA levels: 50 ppm, H2O2 concentrations: 20 ppm Fe+2 levels: 4 ppm, the study found more than 98% DOC removal. In conclusion, the SPF, as an economically effective technique, could be applied for the removal of HA in aqueous environments.

  3. Feed Forward Artificial Neural Network Model to Estimate the TPH Removal Efficiency in Soil Washing Process

    Directory of Open Access Journals (Sweden)

    Hossein Jafari Mansoorian

    2017-01-01

    Full Text Available Background & Aims of the Study: A feed forward artificial neural network (FFANN was developed to predict the efficiency of total petroleum hydrocarbon (TPH removal from a contaminated soil, using soil washing process with Tween 80. The main objective of this study was to assess the performance of developed FFANN model for the estimation of   TPH removal. Materials and Methods: Several independent repressors including pH, shaking speed, surfactant concentration and contact time were used to describe the removal of TPH as a dependent variable in a FFANN model. 85% of data set observations were used for training the model and remaining 15% were used for model testing, approximately. The performance of the model was compared with linear regression and assessed, using Root of Mean Square Error (RMSE as goodness-of-fit measure Results: For the prediction of TPH removal efficiency, a FANN model with a three-hidden-layer structure of 4-3-1 and a learning rate of 0.01 showed the best predictive results. The RMSE and R2 for the training and testing steps of the model were obtained to be 2.596, 0.966, 10.70 and 0.78, respectively. Conclusion: For about 80% of the TPH removal efficiency can be described by the assessed regressors the developed model. Thus, focusing on the optimization of soil washing process regarding to shaking speed, contact time, surfactant concentration and pH can improve the TPH removal performance from polluted soils. The results of this study could be the basis for the application of FANN for the assessment of soil washing process and the control of petroleum hydrocarbon emission into the environments.

  4. Heavy metals removal from acid mine drainage water using biogenic hydrogen sulphide and effluent from anaerobic treatment: Effect of pH

    International Nuclear Information System (INIS)

    Jimenez-Rodriguez, A.M.; Duran-Barrantes, M.M.; Borja, R.; Sanchez, E.; Colmenarejo, M.F.; Raposo, F.

    2009-01-01

    Four alternatives (runs A, B, C and D) for heavy metals removal (Fe, Cu, Zn and Al) from acid mine drainage water (AMDW) produced in the mining areas of the Huelva Province, Spain, were evaluated. In run A, the anaerobic effluent from the treatment of acid mine drainage water (cheese whey added as a source of carbon) was mixed with the raw AMDW. The pH increased to 3.5 with the addition of KOH. In run B, biogas with around 30% of hydrogen sulphide obtained in the anaerobic reactor was sparged to the mixture obtained in run A, but in this case at a pH of 5.5. In run C, the pH of the raw AMDW was increased to 3.5 by the addition of KOH solution. Finally, in run D, the pH of the raw AMDW was increased to 5.5 by the addition of KOH solution and further biogas was sparged under the same conditions as in run A. It was found that heavy metal removal was a function of pH. At a pH of 3.5 most of the iron was removed while Zn and Cu were partially removed. At a pH of 5.5 the removal of all metals increased considerably. The best results were obtained in run B where the percentages of removal of Fe, Cu, Zn and Al achieved values of 91.3, 96.1, 79.0 and 99.0%, respectively. According to the experimental results obtained tentative schemas of the flow diagram of the processes were proposed.

  5. An Intensified Esterification Process of Palm Oil Fatty Acid Distillate Catalyzed by Delipidated Rice Bran Lipase

    Directory of Open Access Journals (Sweden)

    Fui Chin Chong

    2006-01-01

    Full Text Available An intensified esterification process was operated by circulating 10 l of reaction mixtures, consisting of palm oil fatty acid distillate (PFAD and glycerol in hexane, through a packed-bed reactor (PBR filled with 10 kg of delipidated rice bran lipase (RBL. The influence of the process parameters, such as reaction temperature and type of water-removal agent, on the performance of this intensified esterification process were investigated. The highest degree of esterification (61% was achieved at a reaction temperature of 65°C, using silica gels as the water-removal agent. Thin-layer chromatography (TLC analysis showed that the major composition of the esterified product was diacylglycerol.

  6. Metal Removal Process Optimisation using Taguchi Method - Simplex Algorithm (TM-SA) with Case Study Applications

    OpenAIRE

    Ajibade, Oluwaseyi A.; Agunsoye, Johnson O.; Oke, Sunday A.

    2018-01-01

    In the metal removal process industry, the current practice to optimise cutting parameters adoptsa conventional method. It is based on trial and error, in which the machine operator uses experience,coupled with handbook guidelines to determine optimal parametric values of choice. This method is notaccurate, is time-consuming and costly. Therefore, there is a need for a method that is scientific, costeffectiveand precise. Keeping this in mind, a different direction for process optimisation is ...

  7. Formic Acid Free Flowsheet Development To Eliminate Catalytic Hydrogen Generation In The Defense Waste Processing

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, Dan P.; Stone, Michael E.; Newell, J. David; Fellinger, Terri L.; Bricker, Jonathan M.

    2012-09-14

    The Defense Waste Processing Facility (DWPF) processes legacy nuclear waste generated at the Savannah River Site (SRS) during production of plutonium and tritium demanded by the Cold War. The nuclear waste is first treated via a complex sequence of controlled chemical reactions and then vitrified into a borosilicate glass form and poured into stainless steel canisters. Converting the nuclear waste into borosilicate glass canisters is a safe, effective way to reduce the volume of the waste and stabilize the radionuclides. Testing was initiated to determine whether the elimination of formic acid from the DWPF's chemical processing flowsheet would eliminate catalytic hydrogen generation. Historically, hydrogen is generated in chemical processing of alkaline High Level Waste sludge in DWPF. In current processing, sludge is combined with nitric and formic acid to neutralize the waste, reduce mercury and manganese, destroy nitrite, and modify (thin) the slurry rheology. The noble metal catalyzed formic acid decomposition produces hydrogen and carbon dioxide. Elimination of formic acid by replacement with glycolic acid has the potential to eliminate the production of catalytic hydrogen. Flowsheet testing was performed to develop the nitric-glycolic acid flowsheet as an alternative to the nitric-formic flowsheet currently being processed at the DWPF. This new flowsheet has shown that mercury can be reduced and removed by steam stripping in DWPF with no catalytic hydrogen generation. All processing objectives were also met, including greatly reducing the Slurry Mix Evaporator (SME) product yield stress as compared to the baseline nitric/formic flowsheet. Ten DWPF tests were performed with nonradioactive simulants designed to cover a broad compositional range. No hydrogen was generated in testing without formic acid.

  8. Optimization of an Sbr process for nitrogen removal from concentrated wastewater via nitrite

    International Nuclear Information System (INIS)

    Longhi, L.; Basilico, D.; Meloni, A.; Canziani, R.

    2009-01-01

    The results of an experimentation carried out on a pilot-scale Sbr for nitrogen removal via nitridation-denitration are reported. The experimentation was carried out in the period July October 2007 and was aimed at achieving design data for the upgrade of a full scale wastewater treatment plant (WWTP), following the new regulations issued by Lombardy Regional Authority for the discharge of effluents into sensitive areas. One aspect that has been considered in the upgrade is nitrogen removal from the supernatant coming from anaerobic sludge digestion. The experimental results provided sound design data based on real biological activity measurements and operational process parameters such as oxygen and organic carbon requirements. [it

  9. Removal of copper from acid wastewater of bioleaching by adsorption onto ramie residue and uptake by Trichoderma viride.

    Science.gov (United States)

    Wang, Buyun; Wang, Kai

    2013-05-01

    A continuous batch bioleaching was built to realize the bioleaching of sewage sludge in large scale. In the treatment, heavy metal in acid wastewater of bioleaching was removed by adsorption onto ramie residue. Then, acid wastewater was reused in next bioleaching batch. In this way, most time and water of bioleaching was saved and leaching efficiency of copper, lead and chromium kept at a high level in continuous batch bioleaching. It was found that residual heavy metal in sewage sludge is highly related to that in acid wastewater after bioleaching. To get a high leaching efficiency, concentration of heavy metal in acid wastewater should be low. Adsorption of copper from acid wastewater onto ramie residue can be described by pseudo first-order kinetics equation and Freundlich isotherm model. Trichoderma viride has the potential to be used for the concentration and recovery of heavy metal adsorbed onto ramie residue. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Effect of alpha-lipoic acid on the removal of arsenic from arsenic-loaded isolated liver tissues of rat

    Directory of Open Access Journals (Sweden)

    Noor-E-Tabassum

    2006-06-01

    Full Text Available The patient of chronic arsenic toxicity shows oxidative stress. To overcome the oxidative stress, several antioxidants such as beta-carotene, ascorbic acid, α-tocopherol, zinc and selenium had been suggested in the treatment of chronic arsenic toxicity. In the present study universal antioxidant (both water and lipid soluble antioxidant α-lipoic acid was used to examine the effectiveness of reducing the amount of arsenic from arsenic-loaded isolated liver tissues of rat. Isolated liver tissues of Long Evans Norwegian rats were cut into small pieces and incubated first in presence or absence of arsenic and then with different concentrations of α-lipoic acid during the second incubation. α-Lipoic acid decreases the amount of arsenic and malondialdehyde (MDA in liver tissues as well as increases the reduced glutathione (GSH level in dose dependent manner. These results suggest that α-lipoic acid remove arsenic from arsenic-loaded isolated liver tissues of rat.

  11. Organic Micropollutants Removal from Water by Oxidation and Other Processes:QSAR Models, Decision Support System and Hybrids of Processes

    KAUST Repository

    Sudhakaran, Sairam

    2013-08-01

    The presence of organic micropollutants (OMPs) in water is of great environmental concern. OMPs such as endocrine disruptors and certain pharmaceuticals have shown alarming effects on aquatic life. OMPs are included in the priority list of contaminants in several government directorate frameworks. The low levels of OMPs concentration (ng/L to μg/L) force the use of sophisticated analytical instruments. Although, the techniques to detect OMPs are progressing, the focus of current research is only on limited, important OMPs due to the high amount of time, cost and effort involved in analyzing them. Alternatively, quantitative structure activity relationship (QSAR) models help to screen processes and propose appropriate options without considerable experimental effort. QSAR models are well-established in regulatory bodies as a method to screen toxic chemicals. The goal of the present thesis was to develop QSAR models for OMPs removal by oxidation. Apart from the QSAR models, a decision support system (DSS) based on multi-criteria analysis (MCA) involving socio-economic-technical and sustainability aspects was developed. Also, hybrids of different water treatment processes were studied to propose a sustainable water treatment train for OMPs removal. In order to build the QSAR models, the ozone/hydroxyl radical rate constants or percent removals of the OMPs were compiled. Several software packages were used to 5 compute the chemical properties of OMPs and perform statistical analyses. For DSS, MCA was used since it allows the comparison of qualitative (non-monetary, non-metric) and quantitative criteria (e.g., costs). Quadrant plots were developed to study the hybrid of natural and advanced water treatment processes. The QSAR models satisfied both chemical and statistical criteria. The DSS resulted in natural treatment and ozonation as the preferred processes for OMPs removal. The QSAR models can be used as a screening tool for OMPs removal by oxidation. Moreover, the

  12. Humic flotation of wet process phosphoric acid as a pretreatment step in the recovery of uranium

    International Nuclear Information System (INIS)

    Lopez, J.G.; Barnhart, V.J.

    1983-01-01

    An acidic solution containing metal values and also containing humic acid impurities, is purified by: (1) forming a gas in the acid solution, (2) adding high molecular weight anionic organic flocculant in a volume ratio of gas containing acid solution to flocculant of 1,000:0.002 to 0.10, to form a bottom, purified, aqueous acidic phase containing metal values and a top flocculated humic acid impurities froth phase and (3) removing the humic acid froth phase

  13. Performance of Electrocoagulation Process in the Removal of Total Coliform and Hetrotrophic Bacteria from Surface Water

    Directory of Open Access Journals (Sweden)

    Jamshid Derayat

    2015-03-01

    Full Text Available Electrocoagulation is an electrochemical method for the treatment of water and wastewater. The present cross-sectional study was designed to investigate the removal efficiency of total coliform and heterotrophic bacteria from surface water using the process. For this purpose, water samples were taken from the drinking water intake at Suleiman-Shahsonghur Dam. The electrocoagulation process was carried out in a Plexiglas reactor in the batch mode with Al and Fe used electrodes. The experiment design was carried out using the Design Expert Software (Stat-Ease Inc., Ver. 6.0.6. After each run, the values of metals dissolved due to anode electrode dissolution were measured using the Inductively Coupled Plasma (ICP and the results were analyzed using the RSM model. Results revealed maximum removal efficiencies of 100% and 89.1% for total coliform and heterotrophic bacteria using the Al electrode, respectively. Also, maximum removal efficiencies using the Fe electrode for the same pollutants were 100% and 76.1%. The measurements clearly indicate that the quantities of Al and Fe released in water were higher than the recommended values. While the electrocoagulation process showed to be effective in removing microbial agents from surface waters, the high concentrations of dissolved metals due to the dissolution of the anode electrode seem to remain a health problem that requires optimal conditions to be determined for acheiving standard concentrations of the dissolved metals.

  14. Application of Electrocoagulation Process for Reactive Red 198 Dye Removal from the Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Mansooreh Dehghani

    2014-04-01

    Full Text Available Abstract Background and purpose:The main objectives of this research were to evaluating the application of electrocoagulation process for 198 dye from the aqueous phase and determining the optimum operating conditions to the dye removal using aluminum and iron electrodes. Materials and Methods:The present study was conducted in bench-scale. The spectrophotometer DR 5000 was used to determine the dye concentration. The effects of pH, retention time, voltage, dye concentration on the efficiency of electrocoagulation process were investigated. Data were analyzed in SPSS for Windows 16.0 using Pearson’scorrelation coefficient to analyze the relationship between these parameters. Results:The results showed that the optimal conditions for reactive red 198 (RR-198 dye removal from the aqueous solution are pH of 11, the voltage of 32 V, the initial dye concentration of 10 ppm, and the reaction time of 40 min. Pearson correlation analysis showed that there is a significant relationship between voltage and the reaction time with the removal efficiencies (P< 0.01. Conclusion:It was revealed that the removal efficiency of dye was directly proportional to the voltage and reaction time, but inversely proportional to the initial dye concentration. In conclusion, electrocoagulation process using two-fold iron and aluminum electrodes is an appropriate method for reducing the RR-198 dye in the aqueous phase.

  15. Experimental Application of an Advanced Separation Process for NOM Removal from Surface Drinking Water Supply

    Directory of Open Access Journals (Sweden)

    Arianna Callegari

    2017-10-01

    Full Text Available Natural organic matter (NOM in drinking water supplies significantly impacts on water supply quality and treatment, due to observed reactivity with many dissolved and particulate species. Several technologies are used nowadays to remove NOM from the water supply. The evolution of water-related directives, and progressively more restrictive standards for drinking water, however, call for the investigation of advanced, more efficient, and cost-effective water treatment processes. This paper contains a brief overview on the state-of-the-art methods for NOM removal from supply waters, and describes the experimental application of an advanced technology, tested and validated at the pilot scale on the water supply source of a town in Poland. The process allowed significant removal of natural organic matter (about 50% as Dissolved Organic Carbon and turbidity (from 50% to 90%, however, these results requested significant additions of powdered activated carbon. The key to success of this type of process is a correct setup with the identification of optimal types and dosages of reagents. Based on the results of the tests conducted it is foreseeable that this technology could be used onsite, not only for removal of NOM, but also of other hard-to-tackle pollutants potentially contained in the freshwater supply and not presently considered.

  16. Process engineering versus product engineering - A case study on volatile organic compounds removal

    DEFF Research Database (Denmark)

    Coutinho, João A.P.; Vilela, T.; Pereira, P.

    2005-01-01

    Three solutions for removing the dangerous volatile organic compound (VOC) xylene from an industrial coating process are presented and compared. Two of them are based on classical process engineering principles, i.e., development of separation-cleaning methods such as incineration and adsorption...... to the problem-need specified in the beginning of the project, but producing a novel formulation (chemical product design) represents a method that results to a completely xylene-free process which is environmentally and economically more interesting than those generated via the more traditional process...

  17. Superfund TIO videos. Set A. Identifying PRPS. Removal process: Removal site evaluation. Part 2. Audio-Visual

    International Nuclear Information System (INIS)

    1990-01-01

    The videotape is divided into three sections. Section 1 details the liability of Potentially Responsible Parties (PRPs) and describes the four classes of PRPs: current owners and operators, former owners and operators, generators, and transporters (if they selected the site). Section 2 lists the goals of the Potentially Responsible Party (PRP) search and explains how to identify key players during the PRP search. How to plan and conduct the PRP search is also outlined. Section 3 outlines the steps involved in conducting a removal site evaluation. A discussion of when to conduct a removal preliminary assessment, a removal site inspection, and an Engineering Evaluation/Cost Analysis (EE/AC) also is covered

  18. Indian jujuba seed powder as an eco-friendly and a low-cost biosorbent for removal of acid blue 25 from aqueous solution.

    Science.gov (United States)

    Krishna, L Sivarama; Reddy, A Sreenath; Zuhairi, W Y Wan; Taha, M R; Reddy, A Varada

    2014-01-01

    Indian jujuba seed powder (IJSP) has been investigated as a low-cost and an eco-friendly biosorbent, prepared for the removal of Acid Blue 25 (AB25) from aqueous solution. The prepared biomaterial was characterized by using FTIR and scanning electron microscopic studies. The effect of operation variables, such as IJSP dosage, contact time, concentration, pH, and temperature on the removal of AB25 was investigated, using batch biosorption technique. Removal efficiency increased with increase of IJSP dosage but decreased with increase of temperature. The equilibrium data were analyzed by the Langmuir and the Freundlich isotherm models. The data fitted well with the Langmuir model with a maximum biosorption capacity of 54.95 mg g(-1). The pseudo-second-order kinetics was the best for the biosorption of AB25 by IJSP, with good correlation. Thermodynamic parameters such as standard free energy change (ΔG(0)), standard enthalpy changes (ΔH(0)), and standard entropy changes (ΔS(0)) were analyzed. The removal of AB25 from aqueous solution by IJSP was a spontaneous and exothermic adsorption process. The results suggest that IJSP is a potential low-cost and an eco-friendly biosorbent for the AB25 removal from synthetic AB25 wastewater.

  19. Labeling of eukaryotic messenger RNA 5' terminus with phosphorus -32: use of tobacco acid pyrophosphatase for removal of cap structures

    International Nuclear Information System (INIS)

    Lockard, R.E.; Rieser, L.; Vournakis, J.N.

    1981-01-01

    In recent years, there has been a growing appreciation of the potential applications of 5'- 32 P-end-labeled mRNA, not only for screening recombinant clones and mapping gene structure, but also for revealing possible nucleotide sequence and structural signals within mRNA molecules themselves, which may be important for eukaryotic mRNA processing and turnover and for controlling differential rates of translational initiation. Three major problems, however, have retarded progress in this area, lack of methods for efficient and reproducible removal of m7G5ppp5'-cap structures, which maintain the integrity of an RNA molecule; inability to generate a sufficient amount of labeled mRNA, owing to the limited availability of most pure mRNA species; and the frequent problem of RNA degradation during in vitro end-labeling owing to RNAse contamination. The procedures presented here permit one to decap and label minute quantities of mRNA, effectively. Tobacco acid pyrophosphatase is relatively efficient in removing cap structures from even nanogram quantities of available mRNA, and enough radioactivity can be easily generated from minute amounts ofintact mRNA with very high-specific-activity [gamma- 32 P]ATP and the inhibition of ribonuclease contamination with diethylpyrocarbonate. These procedures can be modified and applied to almost any other type of RNA molecule as well. In Section III of this volume, we explore in detail how effectively 5'-end-labeled mRNA can be used not only for nucleotide sequence analysis, but also for mapping mRNA secondary structure

  20. Acidic sweep gas with carbonic anhydrase coated hollow fiber membranes synergistically accelerates CO2 removal from blood.

    Science.gov (United States)

    Arazawa, D T; Kimmel, J D; Finn, M C; Federspiel, W J

    2015-10-01

    The use of extracorporeal carbon dioxide removal (ECCO2R) is well established as a therapy for patients suffering from acute respiratory failure. Development of next generation low blood flow (carbonic anhydrase (CA) immobilized bioactive hollow fiber membrane (HFM) which significantly accelerates CO2 removal from blood in model gas exchange devices by converting bicarbonate to CO2 directly at the HFM surface. This present study tested the hypothesis that dilute sulfur dioxide (SO2) in oxygen sweep gas could further increase CO2 removal by creating an acidic microenvironment within the diffusional boundary layer adjacent to the HFM surface, facilitating dehydration of bicarbonate to CO2. CA was covalently immobilized onto poly (methyl pentene) (PMP) HFMs through glutaraldehyde activated chitosan spacers, potted in model gas exchange devices (0.0151 m(2)) and tested for CO2 removal rate with oxygen (O2) sweep gas and a 2.2% SO2 in oxygen sweep gas mixture. Using pure O2 sweep gas, CA-PMP increased CO2 removal by 31% (258 mL/min/m(2)) compared to PMP (197 mL/min/m(2)) (Premoval by 17% (230 mL/min/m(2)) compared to pure oxygen sweep gas control (Premoval increased by 109% (411 mL/min/m(2)) (Premoval, and when used in combination with bioactive CA-HFMs has a synergistic effect to more than double CO2 removal while maintaining physiologic pH. Through these technologies the next generation of intravascular and paracorporeal respiratory assist devices can remove more CO2 with smaller blood contacting surface areas. A clinical need exists for more efficient respiratory assist devices which utilize low blood flow rates (removal efficiency by shifting equilibrium from bicarbonate to gaseous CO2, through either a bioactive carbonic anhydrase enzyme coating or bulk blood acidification with lactic acid. In this study we demonstrate a novel approach to local blood acidification using an acidified sweep gas in combination with a bioactive coating to more than double CO2 removal

  1. Removal of Lead Hydroxides Complexes from Solutions Formed in Silver/Gold: Cyanidation Process

    Science.gov (United States)

    Parga, José R.; Martinez, Raul Flores; Moreno, Hector; Gomes, Andrew Jewel; Cocke, David L.

    2014-04-01

    The presence of lead hydroxides in "pregnant cyanide solution" decreases the quality of the Dore obtained in the recovery processes of gold and silver, so it is convenient to remove them. The adsorbent capacity of the low cost cow bone powder was investigated for the removal of lead ions from a solution of lead hydroxide complexes at different initial metal ion concentrations (10 to 50 mg/L), and reaction time. Experiments were carried out in batches. The maximum sorption capacity of lead determined by the Langmuir model was found to be 126.58 mg/g, and the separation factor R L was between 0 and 1, indicating a significant affinity of bone for lead. Experimental data follow pseudo-second order kinetics suggesting chemisorption. It is concluded that cow bone powder can be successfully used for the removal of lead ions, and improves the quality of the silver-gold cyanides precipitate.

  2. Thin film removal mechanisms in ns-laser processing of photovoltaic materials

    International Nuclear Information System (INIS)

    Bovatsek, J.; Tamhankar, A.; Patel, R.S.; Bulgakova, N.M.; Bonse, J.

    2010-01-01

    The removal of thin films widely used in photovoltaics (amorphous silicon, tin oxide, zinc oxide, aluminum, and molybdenum) is studied experimentally using multi-kHz Q-switched solid-state lasers at 532 nm and 1064 nm wavelengths. The processing ('scribing') is performed through the film-supporting glass plate at scribing speeds of the order of m/s. The dependence of the film removal threshold on the laser pulse duration (8 ns to 40 ns) is investigated and the results are complemented by a multi-layer thermal model used for numerical simulations of the laser-induced spatio-temporal temperature field within the samples. Possible film removal mechanisms are discussed upon consideration of optical, geometrical, thermal and mechanical properties of the layers.

  3. Fatty acid methyl esters production: chemical process variables

    Directory of Open Access Journals (Sweden)

    Paulo César Narváez Rincón

    2004-05-01

    Full Text Available The advantages of fatty acid methyl esters as basic oleochemicals over fatty acids, the seventies world energy crisis and the use of those oleochemicals as fuels, have increased research interest on fats and oils trans-esterification. In this document, a review about basic aspects, uses, process variables and problems associated to the production process of fatty acid methyl esters is presented. A global view of recent researches, most of them focused in finding a new catalyst with same activity as the alcohol-soluble hydroxides (NaOH, KOH, and suitable to be used in transforming fats and oils with high levels of free fatty acids and water avoiding separation problems and reducing process costs, is also discussed.

  4. Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, M.; Lee, H.J.; Shim, Y. [Korean Mine Reclamation Corporation MIRECO, Seoul (Republic of Korea)

    2010-07-01

    The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 {mu} m, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L{sup -1} FL-2949 (coagulant) and 12 mg L{sup -1} A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

  5. Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation.

    Science.gov (United States)

    Jang, Min; Lee, Hyun-Ju; Shim, Yonsik

    2010-04-01

    The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 microm, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L(-1) FL-2949 (coagulant) and 12 mg L(-1) A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

  6. Acid mine water reclamation using the ABC process

    CSIR Research Space (South Africa)

    De Beer, Morris

    2010-09-01

    Full Text Available of about 2 to 4.5 g/L of sulphate, 250 to 1200 mg/L of Ferrous iron, 60 to 175 mg/L of Mn and 120 mg/L of Mg. The CSIR ABC desalination process, developed for AMD neutralisation and the removal of total dissolved solids from 2 600 to 360 mg/L...

  7. The Use of Electrocoagulation Process for Removal of Turbidity, COD, Detergent and Phosphorus from Carwash Effluent

    Directory of Open Access Journals (Sweden)

    Afshin Takdastan

    2011-10-01

    Full Text Available This study evaluated the efficiency of Electrical coagulation process in removal of COD, turbidity, detergent and phosphate from carwash effluent. An experimental study in laboratory scale was carried out and a glass tank with volume of 3 liters (effective volume of 2 liters containing 4 electrode-page iron and aluminum (AL-AL, AL-Fe, Fe-Fe were used. Electrodes were connected to a power supply with using bipolar method to convert alternative electricity to direct current. Daily samples were collected from different carwash effluents. Initial pH of samples were reported between 7 to 9.At first different tests were performed on primary samples. Percentage of removal was calculated in range pH and electrical potential of 11, 7, 3 and 30, 20, 10 volts respectively. Reaction times were set 90, 60, 30 minutes with middle intervals of 2 cm. The results showed the efficiency of COD removal in the optimum range of  pH=3, voltage of 30 and retention time of 90 minutes removal efficiency in pH of 7 after 90 minutes retention time, voltage of 30, with aluminum electrode reached more than 99%. According to the results obtained electrical energy consumption in aluminum electrodes was less than others. However aluminum is more expensive than iron and the difference in energy consumption between iron and aluminum can be ingnored. Apart from that COD and detergent removal efficiency of iron electrodes is higher than aluminum electrodes therefore, using iron as the electrode is more economical and recommended. Altogether it was found that this method can be use as a safe and convenient method for treating carwash effluent and according to the high removal efficiency of process, effluent can be discharged safely into the environment.

  8. Performance of Electrocoagulation Process for Removal of Sulphate Ion from Aqueous Environments Using Plate Aluminum Electrodes

    Directory of Open Access Journals (Sweden)

    a.h Mahvi

    2012-05-01

    Full Text Available

    Background and Objectives: Sulphate ion is one of the main ions available in natural and waste water. The high rate of sulphate in drinking water causes health problems such as irritation and digestive problems and makes water taste bitter. The purpose of this study was to assess the efficiency of sulphate ion removal from drinking water through Electrocogualation process (EC using plate aluminum electrodes. Methods: This study was conducted as a pilot plant using one glass tank in the volume of 1.3liter containing 6 plate aluminum electrodes. These electrodes were attached to a power supply in a mono-polar and parallel arrangement in order to switch the alternating current to the direct one. That is, each electrode was attached to positive and negative poles directly and alternately. The tank was filled with synthetic water containing sulphate ion with the concentration of 350 & 700mg/L. Percentage of sulphate ion removal in potential range of 10, 20 and 30 V, reaction times of 40, 20 and 60min and pH 7.0, 3.0 & 11.0 were measured. Results: In this study the maximum efficiency of sulphate ion removal was in the electrical potential of 30 V, reaction time of 60min and pH 11.0. With increase of ion concentration, the time needed to achieve a suitable efficiency of removal increased, that is, it indicated the direct effect of pH and difference of electrical potential on removal of sulphate ion through EC process. Conclusion: The results of this research show that Electrocogualation technology can be introduced as a suitable and promising technique to remove sulphate ion from aqueous environments using plate aluminum electrodes.

     

  9. Performance of Electrocoagulation Process for Removal of Sulphate Ion from Aqueous Environments Using Plate Aluminum Electrodes

    Directory of Open Access Journals (Sweden)

    Rajabizadeh A.

    2010-09-01

    Full Text Available Background and Objectives: Sulphate ion is one of the main ions available in natural and waste water. The high rate of sulphate in drinking water causes health problems such as irritation and digestive problems and makes water taste bitter. The purpose of this study was to assess the efficiency of sulphate ion removal from drinking water through Electrocogualation process (EC using plate aluminum electrodes.Methods: This study was conducted as a pilot plant using one glass tank in the volume of 1.3liter containing 6 plate aluminum electrodes. These electrodes were attached to a power supply in a mono-polar and parallel arrangement in order to switch the alternating current to the direct one. That is, each electrode was attached to positive and negative poles directly and alternately. The tank was filled with synthetic water containing sulphate ion with the concentration of 350 & 700mg/L. Percentage of sulphate ion removal in potential range of 10, 20 and 30 V, reaction times of 40, 20 and 60min and pH 7.0, 3.0 & 11.0 were measured.Results: In this study the maximum efficiency of sulphate ion removal was in the electrical potential of 30 V, reaction time of 60min and pH 11.0. With increase of ion concentration, the time needed to achieve a suitable efficiency of removal increased, that is, it indicated the direct effect of pH and difference of electrical potential on removal of sulphate ion through EC process.Conclusion: The results of this research show that Electrocogualation technology can be introduced as a suitable and promising technique to remove sulphate ion from aqueous environments using plate aluminum electrodes.

  10. Removal of odorous materials in carbonization process of dyeing wastewater sludge

    International Nuclear Information System (INIS)

    Bae, Sung-Keun; Woo, Byung-Kyu; Nam, In-Sick; Lee, Joo-Yong; Kim, Gi-Sun

    2010-01-01

    From drying process in a carbonization facility of dyeing wastewater sludge, noxious and odorous materials such as NH 3 , H 2 S, and Volatile Organic Compound (VOCs) contained in the sludge are emitted. In previous studies Regenerative Thermal Oxidizer (RTO) was verified as the most efficient method to eliminate them; nevertheless, it was very expensive to establish and operate because of fuel consumption. To estimate the feasibility of a water spray tower and bio-filter system, laboratory scale experiments for NH 3 , H 2 S, and toluene gas carried out. In case of water spray experiment for the single gas, the removal rate of NH 3 and H 2 S increased as decreasing the concentration, increasing the liquid/ gas ratio, and increasing the retention time. Toluene was eliminated as low as 20% regardless of the above operating parameters. The removal rates of NH 3 and H 2 S were 88∼98% and 80∼83%, respectively. For the mixed gas, the removal rates of NH 3 and toluene was a little dropped, but H 2 S was eliminated slightly more as compared with single gas experiment. Water spray system was not effective for toluene, but it was removed over 90% in bio-filter system. Retention time of gas in bio-filter bed might be an important operating parameter and its optimal condition was considered to 60 seconds. It is experimentally verified that odorous material was very effectively removed by a water spray tower and bio-filter combined system. (author)

  11. Removal of Zn-65, Mo-99 and I-125 from effluent by coagulation-flocculation process

    International Nuclear Information System (INIS)

    Syed Hakimi Sakuma Syed Ahmad

    1996-01-01

    The aim of this study is to investigate the efficiency treatment in removing Zn-65, Mo-99 and I-1 25 from an aqueous radioactive effluent. The wastes are currently being produced from hospitals, research institutes, clinics and universities. Effluent was spiked separately with each type of the radioisotope and was treated by the coagulation-flocculation process. By varying the chemical dosages (i.e., alum, soda ash, ferric chloride and coagulant aid) in the treatment, different decontamination factor values were obtained. Optimum dosages and types of chemical used to remove a particular radioisotope was determined. Results indicated that optimum pH value for removing Zn-65 in an effluent was pH 8. The highest decontamination factor value was 61. In removal of 1-125 radioisotope, ferric chloride was suitable as a coagulant that gives the highest decontamination factor value of 5.0. Treatment to remove Mo-99 radioisotopes was conducted in the laboratory and treatment plant scale. For Mo-99 radioisotope treatment by laboratory and Plant scale, the highest decontamination factor obtained was between pH values of 4.0 to 4.5. By extrapolation of both scales, the plant scale treatment does not vary significantly from laboratory scale. This indicated treatment dosages of chemicals for the Low Level Treatment Plant scale be deduced from the laboratory scale

  12. Uranium geochemistry in estuarine sediments: Controls on removal and release processes

    International Nuclear Information System (INIS)

    Barnes, C.E.; Cochran, J.K.

    1993-01-01

    Porewater uranium profiles from Long Island Sound (LIS) and Amazon shelf sediments and LIS sediment incubation experiments indicate that both removal and release processes control U geochemistry in estuarine sediments. Release of U from sediments occurs in association with Fe reduction. A correlation between U and Fe (and Mn) observed in sediment incubation experiments suggests that there is release of U from Fe-Mn-oxides as they are reduced, consistent with data from the Amazon shelf. In both sediment porewater profiles (LIS and Amazon) and sediment incubation experiments (LIS), there is removal of U from porewater under conditions of sulfate reduction. Sediment incubation experiments indicate that the removal rate is first-order with respect to U concentration, and the rate constant is linearly correlated to sulfate reduction rates. The link between U removal and sulfate reduction (a measure of diagenetic microbial activity) is consistent with a microbial mediation of U reduction. The diffusion flux of U into LIS sediments is estimated from porewater profiles. The inclusion of this estuarine removal term in the oceanic U balance increases the importance of the sediment sink. 62 refs., 12 figs., 2 tabs

  13. Laboratory simulated slipstream testing of novel sulfur removal processes for gasification application

    International Nuclear Information System (INIS)

    Schmidt, Roland; Tsang, Albert; Cross, Joe; Summers, Clinton; Kornosky, Bob

    2008-01-01

    The Wabash River Integrated Methanol and Power Production from Clean Coal Technologies (IMPPCCT) project is investigating an Early Entrance Coproduction Plant (EECP) concept to evaluate integrated electrical power generation and methanol production fro