Sample records for rice husk silica

  1. Mesoporous Silica from Rice Husk Ash

    V.R. Shelke


    Full Text Available Mesoporous silica is used as a raw material in several areas: in preparation of catalysts, in inks, as a concrete hardening accelerator, as a component of detergents and soaps, as a refractory constituent etc. Sodium silicate is produced by reacting rice hull ash (RHA with aqueous NaOH and silica is precipitated from the sodium silicate by acidification. In the present work, conversion of about 90% of silica contained in RHA into sodium silicate was achieved in an open system at temperatures of about 100 °C. The results showed that silica obtained from RHA is mesoporous, has a large surface area and small particle size. Rice Husk is usually mixed with coal and this mixture is used for firing boilers. The RHA therefore, usually contains carbon particles. Activated carbon embedded on silica has been prepared using the carbon already present in RHA. This carbon shows good adsorption capacity. ©2010 BCREC UNDIP. All rights reserved(Received: 25th April 2010, Revised: 17th June 2010, Accepted: 24th June 2010[How to Cite: V.R. Shelke, S.S. Bhagade, S.A. Mandavgane. (2010. Mesoporous Silica from Rice Husk Ash. Bulletin of Chemical Reaction Engineering and Catalysis, 5 (2: 63-67. doi:10.9767/bcrec.5.2.793.63-67][DOI:

  2. Extraction of Silica and other related products from Rice Husk

    Abhishek Mehta,; Dr. R. P Ugwekar


    The main objective of the present work is the synthesis of silica from rice husk and to study its characterization studies. The alkaline method succeeded by acid precipitation is done for the extraction of silica. The optimization of the concentration of sodium hydroxide and the amount of rice husk ash that goes with it for attaining the maximum yield of silica is done. X-ray Diffraction and Fourier Transform Infrared Spectrometry studies are executed for acquiring its characteris...

  3. Extraction of Silica and other related products from Rice Husk

    Abhishek Mehta,


    Full Text Available The main objective of the present work is the synthesis of silica from rice husk and to study its characterization studies. The alkaline method succeeded by acid precipitation is done for the extraction of silica. The optimization of the concentration of sodium hydroxide and the amount of rice husk ash that goes with it for attaining the maximum yield of silica is done. X-ray Diffraction and Fourier Transform Infrared Spectrometry studies are executed for acquiring its characteristic. Activated carbon and silica gel are the intermediate products formed during the synthesis process of silica.

  4. Study of silica templates in the rice husk and the carbon-silica nanocomposites produced from rice husk

    Larichev, Yu. V.; Yeletsky, P. M.; Yakovlev, V. A.


    Carbon-silica nanocomposites obtained by rice husk carbonization in a fluidized-bed reactor using a deep oxidation copper-chromium catalyst were studied. Dispersion characteristics of the silica phase in these systems were determined by small-angle X-ray scattering (SAXS) using the full contrast technique. SiO2 was found in the initial rice husk as compact nanoparticles having a wide size distribution. This distribution consists of a narrow fraction with particle sizes from 1 to 7 nm and a wider fraction with particle sizes from 8 to 22 nm. Oxidative heat treatment of rice husk in a fluidized bed in the presence of the catalyst decreased the fraction of small SiO2 particles and increased the fraction of large ones. It was demonstrated that the particle size of silica in the carbon matrix can be determined selectively for deliberate design of porous carbon materials with desired properties.

  5. Soil Incorporation of Silica-Rich Rice Husk Decreases Inorganic Arsenic in Rice Grain.

    Seyfferth, Angelia L; Morris, Andrew H; Gill, Rattandeep; Kearns, Kelli A; Mann, Jessica N; Paukett, Michelle; Leskanic, Corey


    Arsenic decreases rice yield, and inorganic grain As threatens human health; thus, strategies to decrease rice As are critically needed. Increased plant-available silica (Si) can decrease rice As, yet the source of Si matters. Rice husk, an underutilized and Si-rich byproduct of rice production that contains less labile C and an order of magnitude less As than rice straw, may be an economically viable Si resource to decrease rice As, yet the impact of rice husk incorporation on As in the rice-soil nexus has not been reported. This proof-of-concept study shows that rice husk incorporation to soil (1% w/w) decreases inorganic grain As by 25-50% without negatively affecting grain Cd, yield, or dissolved CH4 levels. Rice husk is a critical yet perhaps overlooked resource to improve soil quality through enhanced nutrient availability and attenuate human health risks through consumption of As-laden grain.


    Leandro Ludueña


    Full Text Available The present work deals with the use of multiple-step procedures to obtain valuable sub-products, including nanocellulose, from rice husk. Each sub-product was characterized after every step by analyzing the chemical composition (mainly based on thermogravimetric analysis, Fourier transformed infrared spectra, and X-ray diffraction and morphology (using visual observations and scanning electron microscopy. The results clearly showed that the selected procedure gave the possibility to separate silica in the first step and then to purify the resultant material, leading to nanocellulose production. All acquired sub-products can be used as additives and fillers in a very wide range of applications. The obtained results will be useful both from technological and academic points of view, mainly for people working in the field of biocomposites. The final material could give added value to a raw biomass material source such as rice husk.

  7. Properties of silica from rice husk and rice husk ash and their utilization for zeolite y synthesis

    Jan-Jezreel F. Saceda; Leon,Rizalinda L. de; Kamolwan Rintramee; Sanchai Prayoonpokarach; Jatuporn Wittayakun


    This study compared properties of silica (SiO2) from rice husk (RH) and rice husk ash (RHA) extracted by acid- and heat-treatment. The SiO2 from RH was in amorphous phase with nearly 100% purity while that from RHA was in crystalline phase with 97.56% purity. Both extracted SiO2 were used in the synthesis of zeolite NaY but that from RH was better due to the efficiency in product recovery and simplicity of extraction. After the NaY was exchanged to NH4Y and calcined to convert to HY, the prod...

  8. Fungus-mediated biotransformation of amorphous silica in rice husk to nanocrystalline silica.

    Bansal, Vipul; Ahmad, Absar; Sastry, Murali


    Rice husk is a cheap agro-based waste material, which harbors a substantial amount of silica in the form of amorphous hydrated silica grains. However, there have been no attempts at harnessing the enormous amount of amorphous silica present in rice husk and its room-temperature biotransformation into crystalline silica nanoparticles. In this study, we address this issue and describe how naturally deposited amorphous biosilica in rice husk can be bioleached and simultaneously biotransformed into high value crystalline silica nanoparticles. We show here that the fungus Fusarium oxysporum rapidly biotransforms the naturally occurring amorphous plant biosilica into crystalline silica and leach out silica extracellularly at room temperature in the form of 2-6 nm quasi-spherical, highly crystalline silica nanoparticles capped by stabilizing proteins; that the nanoparticles are released into solution is an advantage of this process with significant application and commercial potential. Calcination of the silica nanoparticles leads to loss of occluded protein and to an apparently porous structure often of cubic morphology. The room-temperature synthesis of oxide nanomaterials using microorganisms starting from potential cheap agro-industrial waste materials is an exciting possibility and could lead to an energy-conserving and economically viable green approach toward the large-scale synthesis of oxide nanomaterials.

  9. Properties of silica from rice husk and rice husk ash and their utilization for zeolite y synthesis

    Jan-Jezreel F. Saceda


    Full Text Available This study compared properties of silica (SiO2 from rice husk (RH and rice husk ash (RHA extracted by acid- and heat-treatment. The SiO2 from RH was in amorphous phase with nearly 100% purity while that from RHA was in crystalline phase with 97.56% purity. Both extracted SiO2 were used in the synthesis of zeolite NaY but that from RH was better due to the efficiency in product recovery and simplicity of extraction. After the NaY was exchanged to NH4Y and calcined to convert to HY, the product did not carry over the textural properties of the parent NaY and NH4Y.

  10. Characterisation of silica derived from rice husk (Muar, Johor, Malaysia) decomposition at different temperatures

    Azmi, M. A.; Ismail, N. A. A.; Rizamarhaiza, M.; W. M. Hasif. A. A., K.; Taib, H.


    Rice husk was thermally decomposed to yield powder composed of silica (SiO2). Temperatures of 700°C and 1000°C were chosen as the decomposition temperatures. X-Ray Diffraction (XRD), X-Ray Florescence (XRF), Fourier Transform Infrared (FTIR), and Field Emission Scanning Electron Microscope (FESEM) analyses were conducted on a synthetic silica powder (SS-SiO2) and the rice husk ash as for the comparative characterisation study. XRD analyses clearly indicated that the decomposed rice husk yielded silica of different nature which are Crystalline Rice Husk Silica (C-RHSiO2) and Amorphous Rice Husk Silica (A-RHSiO2). Moreover, it was found that SS-SiO2 was of Quartz phase, C-RHSiO2 was of Trydimite and Cristobalite. Through XRF detection, the highest SiO2 purity was detected in SS-SiO2 followed by C-RHSiO2 and A-RHSiO2 with purity percentages of 99.60%, 82.30% and 86.30% respectively. FTIR results clearly indicated silica (SiO2) bonding 1056, 1064, 1047, 777, 790 and 798 cm-1) increased as the crystallinity silica increased. The Cristobalite phase was detected in C-RH SiO2 at the wavelength of 620 cm-1. Morphological features as observed by FESEM analyses confirmed that, SS-SiO2 and C-RH SiO2 showed prominent coarse granular morphology.

  11. Modification of Silica Rice Husk Ash to Solid Ammonium Sulphate for Second Generation Biofuels Productions

    Kasim Mohammed Hello


    Full Text Available A new approach has been demonstrated for the synthesis of solid ammonium sulphate attached to silica rice husk ash. The 3-(aminopropyltriethoxysilane was immobilized onto silica at room temperature to functionalize the silica with ammine end groups (–NH2. The amine group was sulphated with sulphuric acid to produce a novel micro-rod-like shaped acidic catalyst (as seen with TEM designated RHNH3SO4H (RH = rice husk. The TGA analysis shows that the catalyst is stable at temperatures below 200°C. The acidity measurement of the catalyst indicates that it has Brønsted acid sites. Cellulose extracted from waste of rice husk and cellulose extracted from office paper were hydrolysed to glucose in 6 h, and the glucose was hydrolysed afterwards to other products within 13 h. The catalyst is reusable many times without a significant loss of catalytic activity.

  12. Consecutively preparing d-xylose, organosolv lignin, and amorphous ultrafine silica from rice husk.

    Zhang, Hongxi; Ding, Xuefeng; Wang, Zichen; Zhao, Xu


    Rice husk is an abundant agricultural by-product reaching the output of 80 million tons annually in the world. The most common treatment method of rice husk is burning or burying, which caused serious air pollution and resource waste. In order to solve this problem, a new method is proposed to comprehensively utilize the rice husk in this paper. Firstly, the D-xylose was prepared from the semicellulose via dilute acid hydrolysis. Secondly, the lignin was separated via organic solvent pulping from the residue. Finally, the amorphous ultrafine silica was prepared via pyrolysis of the residue produced in the second process. In this way, the three main contents of rice husk (semicellulose, lignin, and silica) are consecutively converted to three fine chemicals, without solid waste produced. The yields of D-xylose and organosolv lignin reach 58.2% and 58.5%, respectively. The purity and specific surface of amorphous ultrafine silica reach 99.92% and 225.20 m(2)/g.

  13. Consecutively Preparing D-Xylose, Organosolv Lignin, and Amorphous Ultrafine Silica from Rice Husk

    Hongxi Zhang


    Full Text Available Rice husk is an abundant agricultural by-product reaching the output of 80 million tons annually in the world. The most common treatment method of rice husk is burning or burying, which caused serious air pollution and resource waste. In order to solve this problem, a new method is proposed to comprehensively utilize the rice husk in this paper. Firstly, the D-xylose was prepared from the semicellulose via dilute acid hydrolysis. Secondly, the lignin was separated via organic solvent pulping from the residue. Finally, the amorphous ultrafine silica was prepared via pyrolysis of the residue produced in the second process. In this way, the three main contents of rice husk (semicellulose, lignin, and silica are consecutively converted to three fine chemicals, without solid waste produced. The yields of D-xylose and organosolv lignin reach 58.2% and 58.5%, respectively. The purity and specific surface of amorphous ultrafine silica reach 99.92% and 225.20 m2/g.




    Renewable biofuels produced by the hydrothermal liquefaction of rice husks have received much attention because of rapid increases in fuel consumption and corresponding declines in fossil fuel resources. To increase biofuel yields, template-free syntheses of Zeolite Socony Mobil (ZSM) catalysts based on blue silica gel and rice husk ash as silica sources were studied. After ZSM synthesis in a closed reactor at 170°C, the crystallinity and crystalline diameters of the products were determined ...

  15. Characterization of silica distribution in rice husk using Synchrotron Radiation µCT and its implications for archaeological interpretation.

    Wu, Yan; Yang, Yimin; Xiao, Tiqiao; Gu, Zhou; Hill, David V; Wang, Changsui


    This article reports the results of a pilot project using Synchrotron Radiation µCT (computer-aided tomography) to examine the distribution of silica within phytoliths from rice husks. Experiments indicate that computed tomography can be used to show how silica accumulates and is distributed in a distinctive zigzag pattern of long epidermal cells that are characteristic of phytoliths from rice husks. This method will help us to understand why the dry ashing method produced much more zigzag pattern of long cells phytoliths from rice husk than did the acid extraction method. Besides, the zigzag morphological pattern exhibited by long epidermal cells is characteristic of this species which makes it useful in the identification of rice husks from archaeological contexts and indicating heating process. © 2014 Wiley Periodicals, Inc.

  16. Lignin isolation process from rice husk by alkaline hydrogen peroxide: Lignin and silica extracted

    Ma'ruf, Anwar; Pramudono, Bambang; Aryanti, Nita


    Biomass is one of abundance resources in the world. Biomass consists of three main materials such as cellulose, hemicelluloses and lignin. Therefore, biomass can be referred to lignocellulosic material. Both the cellulose and hemicelluloses fractions are polymers of sugars, and thereby a potential source of fermentable sugars, or other processes that convert sugars into products. Lignin is a polymer compound which contains of phenolic compounds. Rice husk is one of biomass, which has high contain of lignin. Rice husk has special characteristics because of silica content. The aim of this paper is to analyze lignin and silica extracted during lignin isolation process of rice husk using alkaline hydrogen peroxide. Three main variables such as solvent/solid ratio, concentration of hydrogen peroxide and pH of the mixture are studied. The optimum conditions for lignin isolation are at solvent/solid ratio 9:1 ml/gr, hydrogen peroxide concentration of 1.5%v and pH of the mixture of 11.

  17. Rice Husk Ash as a Renewable Source for the Production of Value Added Silica Gel and its Application: An Overview

    Ram Prasad


    Full Text Available In recent years, silica gels have developed a lot of interest due to their extraordinary properties and their existing and potential applications in science and technology. Silica gel has a wide range of applications such as a desiccant, as a preservation tool to control humidity, as an adsorbent, as a catalyst and as a cata-lyst support. Silica gel is a rigid three-dimensional network of colloidal silica, and is classified as: aqua-gel, alco-gel, xero-gel and aero-gel. Out of all known solid porous materials, aero-gels are particularly known for their high specific surface area, high porosity, low bulk density, high thermal insulation value, ultra low dielectric constant and low index of refraction. Because of these extraordinary properties silica aero-gel has many commercial applications such as thermal window insulation, acoustic barriers, super-capacitors and catalytic supports. However, monolithic silica aero-gel has been used extensively in high energy physics in Cherenkov radiation detectors and in shock wave studies at high pressures, inertial confinement fusion (ICF radio-luminescent and micrometeorites. Silica gel can be prepared by using various sol gel precursors but the rice husk (RH is considered as the cheapest source for silica gel production. Rice husk is a waste product abundantly available in rice producing countries during milling of rice. This review article aims at summarizing the developments carried out so far in synthesis, properties, characterization and method of determination of silica, silica gel, silica aero-gel and silica xero-gel. The effect of synthesis parameters such as pH, temperature of burning the rice husk, acid leaching prior to formation of rice husk ash (RHA on the properties of final product are also described. The attention is also paid on the application of RH, RHA, sil-ica, silica aero-gel and silica xero-gel. Development of economically viable processes for getting rice husk silica with specific

  18. Synthesis of ZSM-5 zeolite using silica from rice husk ash

    Rawtani, A.V.; Rao, M.S. (Dept. of Chemical Engineering, Indian Institute of Technology, Kanpur 208 016 (IN)); Gokhale, K.V.G.K. (Dept. of Civil Engineering, Indian Institute of Technology, Kanpur 208 016 (IN))


    The authors describe ZSM-5 zeolite synthesized from the Na-TPA cation system for the first time using silica from rice husk ash. In this study, rice husk ash was the only source of silica and alumina used in the synthesis. The molar ratio of SiO/sub 2//Al/sub 2/O/sub 3/ in the husk was 24.88, which was constant throughout. The synthesis has been carried out for temperatures ranging from 125 to 200{sup 0}C and durations of synthesis has from 6 to 120 h with Na/sub 2/O/Al/sub 2/O/sub 3/ and H/sub 2/O/Al/sub 2/O/sub 3/ molar ratios ranging from 3.25 to 15.15 and 1081 to 2786, respectively. The effects of varying the composition of initial mixture, the alkalinity, and the time on synthesis were studied. The product at each stage has been characterized by using X-ray diffraction analysis, infrared spectroscopy, differential scanning calorimetry, and electron microscopy.

  19. Upgrading the rice husk char obtained by flash pyrolysis for the production of amorphous silica and high quality activated carbon.

    Alvarez, Jon; Lopez, Gartzen; Amutio, Maider; Bilbao, Javier; Olazar, Martin


    The overall valorization of rice husk char obtained by flash pyrolysis in a conical spouted bed reactor (CSBR) has been studied in a two-step process. Thus, silica has been recovered in a first step and the remaining carbon material has been subjected to steam activation. The char samples used in this study have been obtained by continuous flash pyrolysis in a conical spouted bed reactor at 500°C. Extraction with Na2CO3 allows recovering 88% of the silica contained in the rice husk char. Activation of the silica-free rice husk char has been carried out in a fixed bed reactor at 800°C using steam as activating agent. The porous structure of the activated carbons produced includes a combination of micropores and mesopores, with a BET surface area of up to 1365m(2)g(-1) at the end of 15min.

  20. Biocompatibility assessment of rice husk-derived biogenic silica nanoparticles for biomedical applications

    Alshatwi, Ali A., E-mail:; Athinarayanan, Jegan; Periasamy, Vaiyapuri Subbarayan


    Synthetic forms of silica have low biocompatibility, whereas biogenic forms have myriad beneficial effects in current toxicological applications. Among the various sources of biogenic silica, rice husk is considered a valuable agricultural biomass material and a cost-effective resource that can provide biogenic silica for biomedical applications. In the present study, highly pure biogenic silica nanoparticles (bSNPs) were successfully harvested from rice husks using acid digestion under pressurized conditions at 120 °C followed by a calcination process. The obtained bSNPs were subjected to phase identification analysis using X-ray diffraction, which revealed the amorphous nature of the bSNPs. The morphologies of the bSNPs were observed using transmission electron microscopy (TEM), which revealed spherical particles 10 to 30 nm in diameter. Furthermore, the biocompatibility of the bSNPs with human lung fibroblast cells (hLFCs) was investigated using a viability assay and assessing cellular morphological changes, intracellular ROS generation, mitochondrial transmembrane potential and oxidative stress-related gene expression. Our results revealed that the bSNPs did not have any significant incompatibility in these in vitro cell-based approaches. These preliminary findings suggest that bSNPs are biocompatible, could be the best alternative to synthetic forms of silica and are applicable to food additive and biomedical applications. - Highlights: • Simple, rapid and convenient process • Amorphous and spherical with 10–30 nm size SiO{sub 2} nanoparticles were fabricated. • Biogenic silica nanoparticles showed biocompatibility. • bSNPs are an alternative to synthetic forms of silica.

  1. Reinforcement of natural rubber hybrid composites based on marble sludge/Silica and marble sludge/rice husk derived silica

    Khalil Ahmed


    Full Text Available A research has been carried out to develop natural rubber (NR hybrid composites reinforced with marble sludge (MS/Silica and MS/rice husk derived silica (RHS. The primary aim of this development is to scrutinize the cure characteristics, mechanical and swelling properties of such hybrid composite. The use of both industrial and agricultural waste such as marble sludge and rice husk derived silica has the primary advantage of being eco-friendly, low cost and easily available as compared to other expensive fillers. The results from this study showed that the performance of NR hybrid composites with MS/Silica and MS/RHS as fillers is extremely better in mechanical and swelling properties as compared with the case where MS used as single filler. The study suggests that the use of recently developed silica and marble sludge as industrial and agricultural waste is accomplished to provide a probable cost effective, industrially prospective, and attractive replacement to the in general purpose used fillers like china clay, calcium carbonate, and talc.

  2. Synthesis and Characterization of Microwave Sintered Silica Xerogel Produced from Rice Husk Ash

    Sudiana, I. N.; Mitsudo, S.; Nishiwaki, T.; Susilowati, P. E.; Lestari, L.; Firihu, M. Z.; Aripin, H.


    Silica xerogel ceramic produced from rice husk ash (RHA) taken from South East Sulawesi Indonesia has been successfully sintered by using a millimeter waves (MMW) heating system with a 28 GHz gyrotron as radiation source. The ceramic was also sintered by using an electric furnace where served as a comparison. Densification, microstructural, and morphological characterization of the silica were then investigated by using an Archimedes densification measurement method device, a X-ray diffraction (XRD) and a Scanning Electron Microscopy (SEM), respectively. Effect of microwave energy on the properties of silica xerogel ceramic were evaluated and discussed and compared to conventionally sintered results. The notably different densification and microstructure of sintered samples after sintering were found. The results suggest that microwave radiation provides a microwave effect during sintering.

  3. Preparation of an efficient humidity indicating silica gel from rice husk ash

    J P Nayak; J Bera


    An efficient humidity indicating silica gel was prepared using rice husk ash as a raw material via sodium silicate extraction and acid neutralization method. Cobalt chloride was impregnated into the silica gel as a colour indicating material. A low concentration of cobalt chloride solution (0.0005 mol dm-3) was used for the impregnation. The effect of pH of the impregnating solution on the colour development behaviour of the gel was investigated. The specific surface area of the gel was determined by Brunauer–Emmett–Teller method. The gel has been characterized using X-ray diffraction, scanning electron microscopy and visible spectroscopy. The moisture adsorption and desorption kinetics of the desiccant were evaluated using simultaneous thermogravimetry and differential scanning calorimetry.

  4. Rice Husk Ash-Derived Silica Nanofluids: Synthesis and Stability Study

    Zhang, Zhiliang; He, Wenxiu; Zheng, Jianzhong; Wang, Guangquan; Ji, Jianbing


    Nanofluids, colloidal suspensions consisting of base fluids and nanoparticles, are a new generation of engineering working fluids. Nanofluids have shown great potential in heat/mass transfer applications. However, their practical applications are limited by the high production cost and low stability. In this study, a low-cost agricultural waste, rice husk ash (RHA), was used as a silicon source to the synthesis of silica nanofluids. First, silica nanoparticles with an average size of 47 nm were synthesized. Next, by dispersing the silica nanoparticles in water with ultrasonic vibration, silica nanofluids were formed. The results indicated that the dispersibility and stability of nanofluids were highly dependent on sonication time and power, dispersant types and concentrations, as well as pH; an optimal experiment condition could result in the highest stability of silica nanofluid. After 7 days storage, the nanofluid showed no sedimentation, unchanged particle size, and zeta potential. The results of this study demonstrated that there is a great potential for the use of RHA as a low-cost renewable resource for the production of stable silica nanofluids.

  5. Effect of silica forms in rice husk ash on the properties of concrete

    Bui, Le Anh-Tuan; Chen, Chun-Tsun; Hwang, Chao-Lung; Wu, Wei-Sheng


    The strength and durability properties of concrete with or without three types of rice husk ash (RHA), namely, amorphous, partial crystalline, and crystalline RHA, were investigates. The three types of RHA were added into concrete at a 20% replacement level. Consequently, the pozzolanic reactivity of amorphous RHA was higher than that of partial crystalline and crystalline RHA. Concrete added with amorphous RHA showed excellent characteristics in its mechanical and durability properties. The results showed that the higher the amount of crystalline silica in RHA, the lower the concrete resistivity value became. When compared with each other, concretes with 20% of the cement replaced with these types of RHA achieved similar ultrasonic pulse velocity values, but all were lower than that of the control concrete. The incorporation of these kinds of RHA significantly reduced chloride penetration. The results not only encourage the use of amorphous materials, they also support the application of crystalline or partial crystalline RHA as mineral and pozzolanic admixtures for cement.

  6. Extraction of Pb2+ using Silica from Rice Husks Ash (RHA – Chitosan as Solid Phase

    Hanandayu Widwiastuti


    Full Text Available The existence of lead (Pb compounds in waters can be caused of waste pollution from industrial activities such as dye and battery industries. Lead has toxic characteristic and is able to causing deseases. The levels of Cr(VI can be decreased by methods such as electroplating, oxidation, reduction, and membrane separation. But this methods require high cost and produce a lot of waste. Furthermore, those methods cannot determine the small concentration of Pb2+. Therefore, solid phase extraction is used because it’s a simple method and can be used to preconcentrate Pb2+ ion. The aim of this study is to create solid phase from nature material as an alternative method to determine Pb2+ in water samples. The solid phase is silica from rice husks ash (RHA that was modified using chitosan. To achieve that aim, the optimization of silica : chitosan composition was done. The influence of Pb2+ concentration and citric acid concentration was studied to obtain optimum recovery of Pb2+. Interaction between Pb2+ ion and solid phase silica – chitosan could be estimated based on the result. The result showed the optimum composition of silica : chitosan is 65% silica : 35% chitosan with Cation Exchange Capacity (CEC 0.00455 mek/g. Mass Adsorbed Pb2+for 1 g silica : chitosan 65% is 9.715 mg/g. Optimum recovery of Pb2+ on solid phase extraction is reached at concentration of Pb2+ 10 ppm and citric acid concentration 0.05 M (88.25 % and 81.18 %. This result showed that solid phase extraction using silica – chitosan can be used as an alternative method to determine Pb2+ in water.

  7. Synthesis of zeolite beta with pretreated rice husk silica and its transformation to ZSM-12

    Loiha, Sirinuch [Material Chemistry Research Unit, School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Synchrotron Light Research Institute (Public Organization), Nakhon Ratchasima 30000 (Thailand); Prayoonpokarach, Sanchai [Material Chemistry Research Unit, School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Songsiriritthigun, Prayoon [Synchrotron Light Research Institute (Public Organization), Nakhon Ratchasima 30000 (Thailand); Wittayakun, Jatuporn, E-mail: [Material Chemistry Research Unit, School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Center of Environmental and Hazardous Waste Management (EHWM), Thammasat University, Pathumtani 12120 (Thailand)


    Silica with 98% purity was prepared from rice husk by acid leaching and used as a silica source for the syntheses of zeolite beta (Beta) under hydrothermal conditions with gel Si/Al ratios of 8, 13, 15, 20, 50, 100, 150, and 200. Based on powder X-ray diffraction patterns, samples with gel Si/Al ratios of 8-20 contained only the pure phase of Beta and the highest relative crystallinity was observed in the Beta with gel Si/Al ratio of 13. This sample was further characterized by scanning electron microscopy, particle size analyzer and N{sub 2} adsorption analysis. The Beta particles were sphere shaped with the average particle size of 1.5 {mu}m and a surface area of 670 m{sup 2} g{sup -1}. The samples with gel Si/Al ratios ranging from 50 to 200 showed mixed phases of Beta and ZSM-12, and the latter phase was more dominant as the Si/Al ratio increased.




    Full Text Available Renewable biofuels produced by the hydrothermal liquefaction of rice husks have received much attention because of rapid increases in fuel consumption and corresponding declines in fossil fuel resources. To increase biofuel yields, template-free syntheses of Zeolite Socony Mobil (ZSM catalysts based on blue silica gel and rice husk ash as silica sources were studied. After ZSM synthesis in a closed reactor at 170°C, the crystallinity and crystalline diameters of the products were determined by X-ray diffraction, affording values of 56.33%– 65.81% and 64.3–68.5 nm, respectively. The hydrothermal liquefaction of rice husks with or without a catalyst was conducted in a closed reactor (1200 mm length × 100 mm diameter at 275°C for 45 min. The light biofuel was separated from the ethanol solvent and heavy biofuel via vacuum evaporation. The ZSM catalysts increased the biofuel yields by 2.9%–6.0%. The light biofuels exhibited heating values, flash points, and viscosities of approximately 4.2–4.3 kcal·g−1, 19°C, and 1.48–1.52 cSt, respectively. However, further studies are required to enhance the activity of the ZSMs and increase the quality of the biofuels.

  9. Synthesis of NaX zeolite using silica from rice husk ash

    Dalal, A.K.; Gokhale, K.V.G.K.; Rao, M.S.


    Sodium X zeolite has been synthesized by using rice husk ash as a source of silica for the first time. The synthesis has been carried out for temperatures ranging from 95 to 120 /sup 0/ C and duration of synthesis from 1 to 24 h with SiO/sub 2//AI/sub 2/O/sub 3/, Na/sub 2/O/AI/sub 2/O/sub 3/, and H/sub 2/O/AI/sub 2/O/sub 3/ molar ratios ranging from 2.0 to 7.0, 2.4 to 10.0, and 96.0 to 890.0, respectively. The roles of temperature, duration of synthesis, and composition of initial mix in the formation of NaX zeolite and the stability of NaX zeolite were studied. In the present study, it has been observed that the NaX zeolite can be synthesized from an initial mix with SiO/sub 2//AI/sub 2/O/sub 3/ and Na/sub 2/O/SiO/sub 2/ molar ratios varying from 3 to 5.5 and 0.75 to 2.22, respectively, and having H/sub 2/O/Na/sub 2/O molar ratios from 30 to 60 at 100 /sup 0/ C with reaction times of 6 to 8 h. The product at each stage has been characterized by X-ray diffraction analysis. Studies on the crystallization kinetics and morphological investigations for the formation of NaX zeolite were also carried out.

  10. Synthesis of nanosized ZSM-5 zeolite using extracted silica from rice husk without adding any alumina source

    Sari, Zahra Ghasemi Laleh Vajheh; Younesi, Habibollah; Kazemian, Hossein


    The synthesis of analcime and nanosized ZSM-5 zeolites was carried out by a hydrothermal method with silica extracted from rice husk, available as an inexpensive local biowaste, and without the use of an extra alumina source. Amorphous silica (with 88 wt% of SiO2) was extracted from rice husk ash by a suitable alkali solution. The effects of crystallization temperature, time and SiO2/Al2O3 ratio of the initial system on the properties of final products were investigated. For the characterization of the synthesized product, X-ray diffraction, scanning electron microscope, energy dispersive X-ray techniques, Fourier transform infrared and Brunauer-Emmett-Teller method were applied. Crystallinity percentages of analcime and nanosized ZSM-5 were 95.86 and 89.56, respectively, with specific surface area of 353.5 m2 g-1 for ZSM-5. The experimental results revealed that the synthesis of analcime and nanosized ZSM-5 zeolites was more practical with using silica extracted from inexpensive raw materials, while the whole crystallization process was accomplished without adding any alumina source during.

  11. Recycling rice husks for high-capacity lithium battery anodes.

    Jung, Dae Soo; Ryou, Myung-Hyun; Sung, Yong Joo; Park, Seung Bin; Choi, Jang Wook


    The rice husk is the outer covering of a rice kernel and protects the inner ingredients from external attack by insects and bacteria. To perform this function while ventilating air and moisture, rice plants have developed unique nanoporous silica layers in their husks through years of natural evolution. Despite the massive amount of annual production near 10(8) tons worldwide, so far rice husks have been recycled only for low-value agricultural items. In an effort to recycle rice husks for high-value applications, we convert the silica to silicon and use it for high-capacity lithium battery anodes. Taking advantage of the interconnected nanoporous structure naturally existing in rice husks, the converted silicon exhibits excellent electrochemical performance as a lithium battery anode, suggesting that rice husks can be a massive resource for use in high-capacity lithium battery negative electrodes.

  12. Preparation of TiO2/MCM-41 photocatalyst using rice husk ash as silica source

    Fatimah, Is; Sopia, Lusi


    This work aimed to prepare TiO2/MCM-41 from rice husk ash (RHA) agricultural waste and its application as photocatalyst in dye degradation. The preparation was conducted by two main steps; preparation of MCM-41 and titanium immobilization onto MCM-41. Sol gel method using CTMABr as templating agent was applied in MCM-41 synthesis and as TiO2 precursor, titanium isopropoxide was utilized. The study of physicochemical character change was performed by by X-ray diffraction, IR spectroscopy, BET method and thermogravimetric analysis (TGA). Photocatalytic activity of material was tested in methylene blue photodegradation system. According to the results, it is found that TiO2/MCM-41 has been successfully prepared and shows photocatalytic activity. Kinetic study of the reaction is discussed in this paper.

  13. Utilization of rice husk ash as silica source for the synthesis of mesoporous silicas and their application to CO2 adsorption through TREN/TEPA grafting.

    Bhagiyalakshmi, Margandan; Yun, Lee Ji; Anuradha, Ramani; Jang, Hyun Tae


    Mesoporous MCM-41, MCM-48 and SBA-15 were synthesized using Rice husk ash (RHA) as the silica source and their defective Si-OH sites were functionalized by 3-chloropropyltrimethoxysilane (CPTMS) which was subsequently grafted with amine compounds, Tris(2-aminoethyl)amine (TREN) and Tetraethylenepentamine (TEPA). X-ray powder diffraction (XRD) and BET results of the parent mesoporous silica suggested their closeness of structural properties to those obtained from conventional silica sources. CO(2) adsorption of branched amine TREN and straight chain amine TEPA at 25, 50 and 75 degrees C was obtained by Thermogravimetric Analyser (TGA) at atmospheric pressure. TREN grafted mesoporous silica showed 7% of CO(2) adsorption while TEPA grafted mesoporous silicas showed less CO(2) adsorption, which is due to the presence of isolated amine groups in TREN. TREN grafted mesoporous silicas were also observed to be selective towards CO(2), thermally stable and recyclable. The order of CO(2) adsorption with respect to amount of amine grafting was observed to be MCM-48/TREN>MCM-41/TREN>SBA-15/TREN.

  14. Novel uses of rice-husk-ash (a natural silica-carbon matrix) in low-cost water purification applications

    Malhotra, Chetan; Patil, Rajshree; Kausley, Shankar; Ahmad, Dilshad


    Rice-husk-ash is used as the base material for developing novel compositions to deal with the challenge of purifying drinking water in low-income households in India. For example, rice-husk-ash cast in a matrix of cement and pebbles can be formed into a filtration bed which can trap up to 95% of turbidity and bacteria present in water. This innovation was proliferated in villages across India as a do-it-yourself rural water filter. Another innovation involves embedding silver nanoparticles within the rice husk ash matrix to create a bactericidal filtration bed which has now been commercialized in India as a low-cost for-profit household water purifier. Other innovations include the impregnation of rice-husk-ash with iron hydroxide for the removal of arsenic from water and the impregnation of rice-husk ash with aluminum hydroxide for the removal of fluoride ions from water which together have the potential to benefit over 100 million people across India who are suffering from the health effects of drinking groundwater contaminated with arsenic and fluoride.

  15. Synthesis of MCM-22 zeolite using rice husk as a silica source under varying-temperature conditions.

    Cheng, Yue; Lu, Mang; Li, Jiansheng; Su, Xiaoyuan; Pan, Shunlong; Jiao, Chuang; Feng, Maohua


    In this study, rice husk, an abundant agricultural byproduct, was utilized as an alternative silica source for the synthesis of MCM-22. The zeolite with high crystalline was synthesized using a three-stage varying-temperature hydrothermal method. The prepared silica and MCM-22 were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that the duration required for zeolite crystallization was significantly decreased under varying-temperature conditions. The MCM-22 was in the form of thin platelet-like crystals, and no amorphous material existed in the framework of the MCM-22 after calcination and ammonium exchange. Cationic brilliant red 5GN, a basic dye used in the wool and blanket factories for fiber dyeing, was selected as the adsorptive to study the adsorption performance of the MCM-22. Adsorption experiments indicated that the maximum extent of adsorption was obtained at pH of 10, contact time of 60 min, and MCM-22 dose of 1.0 g/L. The adsorption kinetic has been described by first-order and pseudo-second-order models. It was observed that the rate of dye adsorption followed pseudo-second-order model.

  16. The use of Liquid Smoke as A Substitute for Nitric Acid for Extraction of Amorphous silica from Rice husk through Sol-Gel Route

    Wasinton Simanjuntak


    Full Text Available This study assessed the potential of liquid smoke as substitute for nitric acid for production of rice husk silica using sol-gel method. The efficacy of liquid smoke was compared to that of 10% HNO3 solution in terms of the volume required and the mass of silica obtained. Further evaluation was made by comparing the characteristics of the silica as revealed by several characterization techniques include Fourier infrared spectroscopy, x-ray diffraction, scanning electron microscopy, and particle size analysis. No significant difference between the volume of the liquid smoke and the HNO3 solution required, as well as between the mass of silica obtained. Both samples display practically similar functionality and structure. The most interesting finding is that the silica obtained using liquid smoke exhibits more homogeneous surface morphology and narrower particle size distribution. Considering its environmentally friendly nature, it was concluded that liquid smoke is more advantageous than HNO3 solution.

  17. Utilization Of Rice Husk Ash

    S. D. Nagrale


    Full Text Available India is a major rice producing country, and the husk generated during milling is mostly used as a fuel in the boilers for processing paddy, producing energy through direct combustion and / or by gasification. About 20 million tones of Rice Husk Ash (RHA is produced annually. This RHA is a great environment threat causing damage to the land and the surrounding area in which it is dumped. Lots of ways are being thought of for disposing them by making commercial use of this RHA. RHA can be used as a replacement for concrete (15 to 25%.This paper evaluates how different contents of Rice Husk Ash added to concrete may influence its physical and mechanical properties. Sample Cubes were tested with different percentage of RHA and different w/c ratio, replacing in mass the cement. Properties like Compressive strength, Water absorption and Slump retention were evaluated.

  18. Rice husk ash as a source of silica in alkali-activated fly ash and granulated blast furnace slag systems

    Mejía, J. M.


    Full Text Available This study assesses the viability of using an agro-industrial by-product, rice husk ash (RHA from a Colombian rice company’s combustion facility, as a total replacement for the commercial sodium silicate ordinarily used in alkaliactivated binders. Fly ash (FA, granulated blast furnace slag (GBFS and binary 50FA:50GBFS blended pastes were activated with a mix of sodium hydroxide and either sodium silicate or one of two types of RHA. The pastes were characterised for strength, mineralogy and microstructure. The findings showed that the agro-industrial by-product can be used to yield alkali-activated materials with 7-day mechanical strengths on the order of 42 MPa. The study confirmed that both amorphous silica and part of the crystalline silica present in RHA participate in the alkaline activation process, providing the alkalinity is suitably adjusted.Este estudio evalúa la viabilidad de utilizar un subproducto agroindustrial, la ceniza de cascarilla de arroz (RHA proveniente de un equipo combustor de una empresa Arrocera en Colombia, como reemplazo total de la sílice aportada por el silicato de sodio comercial en sistemas cementicios activados alcalinamente. Se prepararon pastas de ceniza volante (FA, de escoria de alto horno (GBFS y un sistema binario 50FA:50GBFS, que fueron activadas por una mezcla de silicato de sodio e hidróxido de sodio, y por dos tipos de RHA. Las mezclas se caracterizaron mecánica, mineralógica y microestructuralmente. Los resultados demuestran que es posible obtener materiales activados alcalinamente con resistencias mecánicas del orden de 42 MPa, a 7 días de curado, utilizando el subproducto agroindustrial. Este estudio corrobora que tanto la sílice amorfa como parte de la sílice cristalina presente en RHA tienen la posibilidad de participar en el proceso de activación alcalina, siempre y cuando las condiciones de alcalinidad estén adecuadamente ajustadas.

  19. Characterization of AlMCM-41 synthesized with rice husk silica and utilization as supports for platinumiron catalysts

    J. Chumee


    Full Text Available RH-MCM-41 was synthesized by using silica from rice husk and further modified to increase acidity by adding Al with grafting method with Si/Al ratio of 75 and 25. The resulting materials were referred to as RH-AlMCM-41(75 and RH-AlMCM-41(25. The XRD spectra of all RH-AlMCM-41 confirmed a mesoporous structure of MCM-41. Surface areas of all RH-AlMCM-41 were in the range of 700-800 m²/g, lower than that of the parent RH-MCM-41, which was 1230 m²/g. After Al addition the Si/Al ratios of RHAlMCM-41(75 and RH-AlMCM-41(25 were higher than that of the parent RH-MCM-41. The RH-AlMCM41 materials were used as supports for bimetallic platinum-iron catalysts, denoted as Pt-Fe/RH-AlMCM-41, with Pt and Fe amounts of 0.5 and 5.0% by weight, respectively. Results from TPR indicated that the presenceof Al might assist the interaction between Pt and Fe as the reduction temperature of iron oxides shifted to a lower value. All catalysts were active for phenol hydroxylation using H2O2 as an oxidant, for which the highest conversions were observed on the RH-MCM-41 material with the highest surface area. The acidity of the supports did not present a significant role in improving the catalytic performance.

  20. A Comparative Evaluation of Dried Activated Sludge and Mixed Dried Activated Sudge with Rice Husk silica to Remove Hydrogen Sulfide

    Seyed Mahmoud Mehdinia


    Full Text Available The aim of this study was to investigate the effectiveness of dried activated sludge (DAS and mixed dried activated sludge with rice husk silica (DAS & RHS for removal of hydrogen sulfide (H2S. Two laboratory-scale filter columns (packed one litter were operated. Both systems were operated under different conditions of two parameters, namely different inlet gas concentrations and different inlet flow rates. The DAS & RHS packed filter showed more than 99.96% removal efficiency (RE with empty bed residence time (EBRT of 45 to 90 s and 300 mg/L inlet concentration of H2S. However, the RE decreased to 96.87% with the EBRT of 30 s. In the same condition, the DAS packed filter showed 99.37% RE. Nonetheless, the RE was shown to have dropped to 82.09% with the EBRT of 30 s. The maximum elimination capacity (EC was obtained in the DAS & RHS packed filter up to 52.32 g/m3h, with the RE of 96.87% and H2S mass loading rate of 54 g/m3h. The maximum EC in the DAS packed filter was obtained up to 44.33 g/m3h with the RE of 82.09% and the H2S mass loading rate of 54 g/m3h. After 53 days of operating time and 54 g/m3h of loading rates, the maximum pressure drop reached to 3.0 and 8.0 (mm H2O for the DAS & RHS packed and DAS packed filters, respectively. Based on the findings of this study, the DAS & RHS could be considered as a more suitable packing material to remove H2S.

  1. Synthesis of biogenic silicon/silica (Si/SiO2) nanocomposites from rice husks and wheat bran through various microorganisms

    Kaur, Taranjot; Pal Singh, Gurwinder; Kaur, Gurneet; Kaur, Sukhvir; Gill, Prabhjot Kaur


    Biosilification is an economically viable, energy saving and green approach for the commercial scale synthesis of oxide nanomaterials. The room temperature synthesis of oxide nanocomposites from cost effective agro-based waste is a particular example of biosilification. In this study, synthesis of Si/SiO2 nanocomposites from inexpensive agro-based waste material i.e. rice husks (RH) and wheat bran (WB) has been carried out by means of various eukaryotic microorganisms, i.e. Actinomycete, Fusarium oxysporum, Aspergillus niger, Trichoderma sp. and Penicillium sp., under ambient conditions. The XRD diffrectrograms represents that the synthesized nanomaterials exhibits silicon, amorphous silica and other crystal arrays such as cristobalite, trydimite and quartz, depending upon the type microorganism and time period used for extraction. All of the aforesaid microorganism bio transformed the naturally occurring amorphous silica to crystalline structures within the period of 24 h. However, the Actinomycete and Trichoderma sp. took 48 h in case of rice husks for biotransformation of naturally occurring plant silica to crystalline nanocomposite. While in case of wheat bran, Actinomycete and Trichoderma sp. took 24 h for biotransformation. The extracted nanocomposites exhibits band edge in the range 230-250 nm and blue emission. The procedure described in study can be used for commercial level production of Si/SiO2 nanocomposites from agro based waste materials.


    Simon Sembiring


    Full Text Available In this research, borosilicate ceramics were produced from rice husk silica. Preparation of borosilicate ceramics was conducted by mixing boron oxide sol from borax with silica sol extracted from rice husk. The boron oxide was produced by hydrolysis of borax using H2SO4 5%. The samples were synthesized with different compositions, with the ratios of silica to boron oxide are 8:1, 8:2, 8:3 and 8:4. The samples were sintered at 900 °C. Functional groups were examined using FTIR spectroscopic technique. Structural and microstructural characteristics were examined by XRD and SEM, respectively. The chemical resistance of borosilicate is evaluated by gravimetric method using H2SO4, HCl, NaOH and KOH. The FTIR study revealed that the main functional groups are Si-O-Si, B-O-B, and B-O-Si. The x-ray diffraction (XRD study revealed that the main crystalline phases are borosilicate (B2SiO5 and boron oxide (B2O3. SEM investigations clearly demonstrated that the smaller particle size was found with increasing in boron oxide concentration. From the chemical resistance test carried out, it was obtained that the produced borosilicate possessed high resistance to acids and alkalis.

  3. Performance at high temperature of alkali-activated slag pastes produced with silica fume and rice husk ash based activators

    Bernal, S. A.


    Full Text Available This study assessed the mechanical properties, and structural changes induced by high temperature exposure, of alkali-silicate activated slag cements produced with sodium silicates derived from silica fume (SF and rice husk ash (RHA. Similar reaction products were identified, independent of the type of silicate used, but with subtle differences in the composition of the C-S-H gels, leading to different strength losses after elevated temperature exposure. Cements produced with the alternative activators developed higher compressive strengths than those produced with commercial silicate. All samples retained strengths of more than 50 MPa after exposure to 600 °C, however, after exposure to 800 °C only the specimens produced with the RHA-based activator retained measurable strength. This study elucidated that silicate-activated slag binders, either activated with commercial silicate solutions or with sodium silicates based on SF or RHA, are stable up to 600 °C.Este estudio evaluó las propiedades mecánicas, y cambios estructurales inducidos por exposición a temperaturas elevadas, de cementos de escoria activada alcalinamente producidos con silicatos sódicos derivados de humo de sílice (SF y ceniza de cascarilla de arroz (RHA. Se identificaron productos de reacción similares, independiente del tipo de silicato utilizado, pero con diferencias menores en la composición de las geles C-S-H, lo cual indujo diferentes pérdidas de resistencia posterior a exposición a temperaturas elevadas. Los cementantes producidos con los activadores alternativos desarrollaron resistencias a la compresión más altas que aquellos producidos con silicato comercial. Todas las muestras retuvieron resistencias de más de 50 MPa posterior a la exposición a 600 °C, sin embargo, posterior a la exposición a 800 °C únicamente muestras producidas con activadores de RHA retuvieron resistencias medibles. Este estudio elucidó que cementantes de escoria activada con

  4. One-Pot and Efficient Synthesis of Triazolo[1,2-a]indazole-triones via Reaction of Arylaldehydes with Urazole and Dimedone Catalyzed by Silica Nanoparticles Prepared from Rice Husk

    Asadollah Hassankhani; Sayed Zia Mohammadi; Hooshang Hamidian; Samieh Fozooni


    A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions and environmental friendliness.

  5. One-Pot and Efficient Synthesis of Triazolo[1,2-a]indazole-triones via Reaction of Arylaldehydes with Urazole and Dimedone Catalyzed by Silica Nanoparticles Prepared from Rice Husk

    Asadollah Hassankhani


    Full Text Available A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions and environmental friendliness.

  6. One-pot and efficient synthesis of triazolo[1,2-a]indazole-triones via reaction of arylaldehydes with urazole and dimedone catalyzed by silica nanoparticles prepared from rice husk.

    Hamidian, Hooshang; Fozooni, Samieh; Hassankhani, Asadollah; Mohammadi, Sayed Zia


    A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions and environmental friendliness.

  7. Preparation and characterization of rice husk/ferrite composites


    A novel ferrite composite using rice husk as substrate has been prepared via high temperature treatment under nitrogen atmosphere.The rice husk substrate consists of porous activated carbon and silica,where spinel ferrite particles with average diameter of 59 nm are distributed.The surface area of the composite is greater than 170 m~2 g~(-1) and the bulk density is less than 0.6 g cm~(-3).Inert atmosphere is indispensable for the synthesis of pure ferrite composites,while different preparation temperatur...

  8. Nano Silica with High Surface Area from Rice Husk as a Support for 12-Tungstophosphoric Acid: An Efficient Nano Catalyst in Some Organic Reactions%Nano Silica with High Surface Area from Rice Husk as a Support for 12-Tungstophosphoric Acid:An Efficient Nano Catalyst in Some Organic Reactions



    Nano silica was prepared from rice husk with high surface area.X-ray diffraction (XRD) pattern showed that the amorphous form of silica was produced.Chemical composition of the nano silica was estimated by X-ray fluorescence spectroscopy and CHN analysis.The nano silica was used as a support for H3PW12O40.The nano silica and nano silica supported H3PW12O40were characterized by inductively coupled plasma,XRD,transmission electron microscopy (TEM),N2 adsorption-desorption,and Fourier transform infrared spectroscopy.TEM images of nano silica as well as the supported catalyst displayed average size of 6 and 7 nm,respectively.The catalyst showed excellent activity in some important organic reactions including Biginelli,Hantzsch,Mannich,and Claisen-Schmidt reactions with good reusability.Catalytic activity of this nano catalyst is an improvement over the commercially available silica that is used to support H3PW12O40.

  9. Processing Methods of Alkaline Hydrolysate from Rice Husk

    Olga D. Arefieva


    Full Text Available This paper devoted to finding processing methods of alkaline hydrolysate produced from rice husk pre-extraction, and discusses alkaline hydrolysate processing schemed and disengagement of some products: amorphous silica of various quality, alkaline lignin, and water and alkaline extraction polysaccharides. Silica samples were characterized: crude (air-dried, burnt (no preliminary water treatment, washed in distilled water, and washed in distilled water and burnt. Waste water parameters upon the extraction of solids from alkaline hydrolysate dropped a few dozens or thousand times depending on the applied processing method. Color decreased a few thousand times, turbidity was virtually eliminated, chemical oxygen demanded about 20–136 times; polyphenols content might decrease 50% or be virtually eliminated. The most prospective scheme obtained the two following solid products from rice husk alkaline hydrolysate: amorphous silica and alkaline extraction polysaccharide. Chemical oxygen demand of the remaining waste water decreased about 140 times compared to the silica-free solution.

  10. Crystallization kinetic study of the lithium-disilicate bioceramic obtained from rice-husk silica starting powder; Estudo cinetico da cristalizacao da bioceramica de dissilicato de litio obtida atraves da silica da casca de arroz

    Santos, F.A.; Santos, C.; Pinatti, D.G., E-mail: [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia; Lazar, D.R.R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Davim, E.; Fernandes, M.H.F.V. [Universidade de Aveiro, Campos Universitario de Santiago, Aveiro (Portugal)


    In this work, the study of crystallization of the lithium disilicate glass-ceramic produced for alternative source (rice husk silica), and comparatively by commercial source (commercial silica) it was carried through. The stoichiometry 66%.mol SiO{sub 2}: 33%.mol LiO{sub 2} was used. The kinetic studies of crystallization and calculations had been carried through thermal analysis (DTA), and were possible to study the behavior of the curves in accordance with the variation of taxes (5; 10; 15; e 20°C/min), of the granulometries 63 μm, 250μm and 1mm), and for the influence of the substitution commercial SiO{sub 2} by rice husk. The structural characterization was carried through by X-Ray diffractometry (DRX) and scanning electron microscopy (MEV), for chemical characterization used X-Ray fluorescence (FRX). The preliminary results show that the substitution of the silica source is sufficiently promising, since the gotten properties are similar. (author)

  11. Adsorption of Pb(II) using silica gel composite from rice husk ash modified 3-aminopropyltriethoxysilane (APTES)-activated carbon from coconut shell

    Yusmaniar, Purwanto, Agung; Putri, Elfriyana Awalita; Rosyidah, Dzakiyyatur


    Silica gel modified by 3-aminopropyltriethoxysilane (APTES) was synthesized from rice husk ash combined with activated carbon from coconut shell yielded the composite adsorbent. The composite was characterized by Fourier Transform Infra Red spectroscopy (FT-IR), Electron Dispersive X-Ray (EDX), Surface Area Analyzer (SAA) and adsorption test by Atomic Absorption Spectrometry (AAS). This composite adsorbent has been used moderately for the removal of lead ions from metal solutions and compared with silica gel modified APTES and activated carbon. The adsorption experiments of Pb -ions by adsorbents were performed at different pH and contact time with the same metal solutions concentration, volume solution, and adsorbent dosage. The optimum pH for the adsorption was found to be 5.0 and the equilibrium was achieved for Pb with 20 min of contact time. Pb ions adsorption by composite silica gel modified APTES-activated carbon followed by Langmuir isotherm model with qmax value of 46.9483 mg/g that proved an adsorbent mechanism consistent to the mechanism of monolayer formation.

  12. Effect of sintering temperature variations on fabrication of 45S5 bioactive glass-ceramics using rice husk as a source for silica.

    Leenakul, Wilaiwan; Tunkasiri, Tawee; Tongsiri, Natee; Pengpat, Kamonpan; Ruangsuriya, Jetsada


    45S5 bioactive glass is a highly bioactive substance that has the ability to promote stem cell differentiation into osteoblasts--the cells that create bone matrix. The aim of this work is to analyze physical and mechanical properties of 45S5 bioactive glass fabricated by using rice husk ash as its silica source. The 45S5 bioactive glass was prepared by melting the batch at 1300 °C for 3h. The samples were sintered at different temperatures ranging from 900 to 1050 °C with a fixed dwell-time of 2h. The phase transitions, density, porosity and microhardness values were investigated and reported. DTA analysis was used to examine the crystallization temperatures of the glasses prepared. We found that the sintering temperature had a significant effect on the mechanical and physical properties of the bioactive glass. The XRD showed that when the sintering temperature was above 650 °C, crystallization occurred and bioactive glass-ceramics with Na2Ca2Si3O9, Na2Ca4(PO4)2SiO4 and Ca3Si2O7 were formed. The optimum sintering temperature resulting in maximum mechanical values was around 1050 °C, with a high density of 2.27 g/cm(3), 16.96% porosity and the vicker microhardness value of 364HV. Additionally, in vitro assay was used to examine biological activities in stimulated body fluid (SBF). After incubation in SBF for 7 days, all of the samples showed formations of apatite layers indicating that the 45S5 bioactive glasses using rice husk as a raw material were also bioactive.

  13. Preparation of TiO2-SiO2 using Rice Husk Ash as Silica Source and The Kinetics Study as Photocatalyst in Methyl Violet Decolorization

    Is Fatimah


    Full Text Available Preparation, characterization and utilization of TiO2-SiO2 as photocatalyst for methyl violet (MV decolorization has been conducted. In this research, preparation of TiO2-SiO2 was developed based on natural renewable silica source; rice husk ash (RHA via a sol-gel technique. The composite was formed by the dispersing of titanium isopropoxide as titania precursor into the gel of silica followed by aging, drying and calcination. The TiO2-SiO2 sample was characterized by powder X-ray diffraction (XRD, diffuse reflectance-UV Visible spectrophotometric analysis (DRUV-Vis, gas sorption analyzer and Scanning electron micrograph (SEM before its utilization as photocatalyst in methyl violet photooxidation. As comparison to the physicochemical character study, the synthesis of TiO2-SiO2 by using tetraethyl ortosilicate (TEOS was performed as a confirmation. Result showed that prepared TiO2-SiO2 has the character similar to TiO2-SiO2 as synthesized by TEOS precursor. The formation of crystalline titania in anatase and rutile phase was identified with increasing surface porosity data and the value of band gap energy which sufficiently contribute to a photocatalytic mechanism. The character data are in line with the kinetic data of methyl violet decolorization. From the compared photooxidation, photolysis, photocatalysis and adsorption process, it can be concluded that TiO2-SiO2 acts efficiently as a photocatalyst. © 2015 BCREC UNDIP. All rights reserved.Received: 23rd August 2014; Revised: 4th October 2014; Accepted: 20th October 2014 How to Cite: Fatimah, I., Said, A., Hasanah, U.A. (2015. Preparation of TiO2-SiO2 using Rice Husk Ash as Silica Source and The Kinetics Study as Photocatalyst in Methyl Violet Decolorization. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (1: 43-49. (doi:10.9767/bcrec.10.1.7218.43-49Permalink/DOI: 

  14. Rice Husk Ash Sandcrete Block as Low Cost Building Material



    Full Text Available Concrete is a widely used construction material for various types of structures due to its structural stability and strength. The construction industry is today consuming more than 400 million tonnes of concrete every year .Most of the increase in cement demand will be met by the use of supplementary cementing materials, as each ton of Portland cement clinker production is associated with similar amount of CO2 emission, which is a major source of global warming. Partial replacement of ordinary Portland cement with mineral admixtures like fly ash, ground granulated blast furnace slag, silica fume, metakaolin, Rice husk Ash (RHA,etc with plasticizers eliminates these drawbacks. The use of rice husk modifies the physical qualities of fresh cement paste as well as microstructure of paste after hardening. By burning the rice husk under a uncontrolled temperature in the atmosphere, a highly reactive RHA was obtained and the ash was utilized as a supplementary cementing material. This paper presents the effects of using Rice Husk Ash (RHA as a partial cement replacement material in mortar mixes. This work is based on an experimental study of mortar made with replacement of Ordinary Portland Cement (OPC with 10%, 20% 30% & 40% RHA. The properties investigated were the compressive strength, setting time, consistency, workability and specific gravity. Finally, a cost analysis was also done to compare the efficiency of rice husk ash sandcrete blocks. From the test results it can be concluded that rice husk ash can be utilized in day today life of manufacturing building blocks which are more economical and more eco-friendly than the cement concrete blocks which are produced now-a-days.

  15. Studies on Thermal Degradation Behavior of Siliceous Agriculture Waste (Rice Husk, Wheat Husk and Bagasse

    Javed Syed H.


    Full Text Available Various siliceous agriculture waste (SAW such as rice husk, wheat husk and bagasse have been investigated to study their thermal degradation behavior using Thermogravimetric Analyzer (TGA technique. The focus of this research is to conduct TGA of raw and acid treated (20% HCl & 1M H2SO4 SAW at heating rate 10°C/min in the atmosphere of nitrogen. The results were analyzed on the basis of thermograms and it was inferred that 24 hours soaking with 20% HCl prior to thermal degradation enhanced the percent weight loss. The process also improved the percentage of residual weight of SAW indicating the extraction of amorphous silica with increased purity. The effect of acid treatment was verified by determining chemical composition of SAW samples before and after soaking with 20% HCl. Proximate analysis, thermal degradation temperature ranges and percentage of residual weight at 800°C for each of rice husk, wheat husk and bagasse were also quantified to observe the thermal degradation behavior. XRF analysis was performed to observe the effect of acid treatment for extraction of pure silica.

  16. Characterization of platinum–iron catalysts supported on MCM-41 synthesized with rice husk silica and their performance for phenol hydroxylation

    Jitlada Chumee, Nurak Grisdanurak, Arthit Neramittagapong and Jatuporn Wittayakun


    Full Text Available Mesoporous material RH-MCM-41 was synthesized with rice husk silica by a hydrothermal method. It was used as a support for bimetallic platinum−iron catalysts Pt–Fe/RH-MCM-41 for phenol hydroxylation. The catalysts were prepared by co-impregnation with Pt and Fe at amounts of 0.5 and 5.0 wt.%, respectively. The RH-MCM-41 structure in the catalysts was studied with x-ray diffraction, and their surface areas were determined by nitrogen adsorption. The oxidation number of Fe supported on RH-MCM-41 was + 3, as determined by x-ray absorption near edge structure (XANES analysis. Transmission electron microscopy (TEM images of all the catalysts displayed well-ordered structures, and metal nanoparticles were observed in some catalysts. All the catalysts were active for phenol hydroxylation using H2O2 as the oxidant at phenol : H2O2 mole ratios of 2 : 1, 2 : 2, 2 : 3 and 2 : 4. The first three ratios produced only catechol and hydroquinone, whereas the 2 : 4 ratio also produced benzoquinone. The 2 : 3 ratio gave the highest phenol conversion of 47% at 70 °C. The catalyst prepared by co-impregnation with Pt and Fe was more active than that prepared using a physical mixture of Pt/RH-MCM-41 and Fe/RH-MCM-41.

  17. Chemical Looping Combustion of Rice Husk

    Rashmeet Singh Monga


    Full Text Available A thermodynamic investigation of direct chemical looping combustion (CLC of rice husk is presented in this paper. Both steam and CO2 are used for gasification within the temperature range of 500–1200˚C and different amounts of oxygen carriers. Chemical equilibrium model was considered for the CLC fuel reactor. The trends in product compositions of the fuel reactor, were determined. Rice husk gasification using 3 moles H2O and 0 moles CO2 per mole carbon (in rice husk at 1 bar pressure and 900˚C was found to be the best operating point for hundred percent carbon conversion in the fuel reactor. Such detailed thermodynamic studies can be useful to design chemical looping combustion processes using different fuels.

  18. Use of rice husk ash as only source of silica in the formation of mesoporous materials Emprego da cinza da casca de arroz como única fonte de sílica na formação de materiais mesoporosos

    A. J. Schwanke


    Full Text Available This paper reports the synthesis of molecular sieves similar to MCM-41 using rice husk ash as only source of silica. For comparison purposes, a standard synthesis was performed using aerosil 200 commercial silica. The rice husk silica was obtained by heating treatment at 600 ºC and leaching for 2 h in reflux with HCl 1mol.L-1 and used in the synthesis. The samples prepared were characterized by N2 adsorption, X-ray diffraction (XRD, scanning electronic microscopy (SEM and thermogravimetric analysis (TG. By type-IV adsorption isotherms, the formation of mesoporous materials was observed. XRD showed the formation of hexagonal unidirectional pore materials similar to MCM-41. By SEM, it could be observed that the rice husk has fibrous aspect and that synthesis using calcined and leached rice husk did not react entirely because silica was only partially dissolved.Este trabalho relata o estudo da síntese de peneiras moleculares semelhantes à MCM-41, empregando cinza da casca de arroz como única fonte de sílica. Para critérios de comparação uma síntese foi realizada com sílica comercial aerosil 200. A sílica da casca de arroz foi obtida mediante tratamento térmico a 600 ºC e lixiviação em refluxo por 2 h com HCl 1 mol/L e empregada na síntese. As amostras preparadas foram caracterizadas por adsorção de N2, difração de raios X, microscopia eletrônica de varredura (MEV e termogravimetria. Por meio das isotermas de adsorção, do tipo IV, observa-se a formação de material mesoporoso. Nos difratogramas de raios X é identificada a formação hexagonal unidirecional de poros, indicando que material apresenta semelhanças com a MCM-41. Por MEV observa-se que a casca de arroz possui aspecto fibroso e que a síntese empregando a casca de arroz calcinada e lixiviada não reagiu na sua totalidade devido a dissolução parcial da sílica.


    Suyanta Suyanta


    Full Text Available The research about synthesis and characterization of MCM-41 from rice husk has been done. Silica (SiO2 was extracted from rice husk by refluxing with 3M hydrochloric solution at 80 °C for 3 h. The acid-leached rice husk was filtered, washed, dried and calcined at 650 °C for 6 h lead the rough powder of rice husk silica with light brown in color. Characterization was carried out by X-ray diffraction (XRD and FTIR spectroscopy method. Rice husk silica was dissolved into the sodium hydroxide solution leading to the solution of sodium silicate, and used as silica source for the synthesis of MCM-41. MCM-41 was synthesized by hydrothermal process to the mixture prepared from 29 g of distilled water, 8.67 g of cetyltrimethyl ammonium bromide (CTMAB, 9.31 g of sodium silicate solution, and amount mL of 1 M H2SO4. Hydrothermal process was carried out at 100 °C in a teflon-lined stainless steel autoclave heated in the oven for 36 h. The solid phase was filtered, then washed with deionised water, and dried in the oven at 100 °C for 2 h. The surfactant CTMAB was removed by calcination at 550 °C for 10 h with heating rate 2 °C/min. The as-synthesized and calcined crystals were characterized by using FTIR spectroscopy, X-ray diffraction and N2 physisorption methods. In order to investigate the effect of silica source, the same procedure was carried out by using pure sodium silicate as silica source. It was concluded that silica extracted from rice husk can be used as raw materials in the synthesis of MCM-41, there is no significant difference in crystallinity and pore properties when was compared to material produced from commercial sodium silicate.

  20. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Ahiduzzaman, Md; Sadrul Islam, A K M


    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  1. Developing high-performance concrete incorporating highly-reactive rice husk ash

    Andrés Salas


    Full Text Available The aim of this study is to present results of an investigation about the developing of a highperformance concrete (HPC using a highly reactive pozzolan made from chemically treated rice husk ash (ChRHA prepared by a chemical-thermal attack to the rice husk. This particular rice husk ash (RHA consists of 99% of silica, highly amorphous, white in color and of greater pozzolanic activity than the silica fume and another rice husk ash prepared with only by a thermal treatment. The results of the physical, chemical and mineralogical characteristics of ChRHA are analyzed. In this study, the compressive strength, flexural strength, water absorption, resistance to carbonation, total charge-passed derived from rapid chloride permeability test (RCPT and modulus of elasticity of hardened concrete were determined in the laboratory. Test results indicate that it is possible to produce HPC with the incorporation the chemically treated RHA. The incorporation of the chemically treated rice husk ash into the concrete enhances the compressive strengthand the durability properties being comparable to the properties of high performance concretes with silica fume (SF made with the same replacement levels.

  2. Production of activated carbon from rice husk Vietnam

    Korobochkin, V. V.; Tu, N. V.; Hieu, N. M.


    This work is dedicated to the production of activated carbon from rice husk from Delta of the Red River in Viet Nam. At the first stage, carbonization of a rice husk was carried out to obtain material containing 43.1% carbon and 25 % silica with a specific surface area of 51.5 m2/g. After separating of silica (the second stage), the specific surface area of the product increased to 204 m2/g and the silica content decreased to 1.23% by weight as well. The most important stage in the formation of the porous structure of the material is the activation. The products with the high specific surface area in the range of 800-1345 m2/g were obtained by activation of carbonized product with water vapour or carbon dioxide at temperatures of 700 °C and 850 °C, with varying the flow rate of the activating agent and activation time. The best results were achieved by activation of carbon material with water vapour at the flow rate of 0.08 dm3/min per 500 g of material and the temperature of 850 °C.

  3. Medium-density particleboards from modified rice husks and soybean protein concentrate-based adhesives.

    Ciannamea, Emiliano M; Stefani, Pablo M; Ruseckaite, Roxana A


    The main goal of this work was to evaluate the technical feasibility of using rice husk (RH) as wood substitute in the production of environmentally sound medium-density particleboards using adhesives from soybean protein concentrate (SPC). Chemical modification of rice husk with sodium hydroxide and sodium hydroxide followed by hydrogen peroxide (bleaching) were undertaken to evaluate the effect of such treatments on the composition and topology of rice husk and the performance of produced panels. Both treatments were efficient in partially eliminating hemicelluloses, lignin and silica from RH, as evidenced by thermo-gravimetric analysis (TGA). Scanning electron microscopy observations suggested that alkaline treatment resulted in a more damaged RH substrate than bleaching. The dependence of mechanical properties (modulus of rupture, modulus of elasticity, and internal bond) and the physical properties (water absorption and thickness swelling) on chemical treatments performed on both, rice husk and SPC was studied. Bleached-rice husk particleboards bonded with alkaline-treated soybean protein concentrate displayed the best set of final properties. Particleboards with this formulation met the minimum requirements of internal bond, modulus of elasticity and modulus of rupture recommended by the US Standard ANSI/A208.1 specifications for M1, MS and M2-grade medium-density particleboards, but failed to achieve the thickness swelling value recommended for general use panels. This limitation of soybean protein concentrate-bonded rice husk particleboards was counterbalanced by the advantage of being formaldehyde-free which makes them a suitable alternative for indoor applications.


    Bwire S. Ndazi


    Full Text Available Chemical and thermal stability of rice husks against alkali treatment with 2 to 8% w/v NaOH are presented and discussed in this paper. The thermal stability of the rice husks was examined by using a thermal gravimetric analysis instrument. Chemical stability was evaluated by examining the organic components of rice husks using proximate analysis. The results indicated that the proportion of lignin and hemicellulose in rice husks treated with NaOH ranging from 4 to 8% decreased significantly by 96% and 74%, respectively. The thermal stability and final degradation temperatures of the alkali-treated rice husks were also lowered by 24-26°C due to degradation of hemicellulose and lignin during alkali treatment. Absence of the onset degradation zones in the alkali-treated rice husks was a further indication that hemicellulose and other volatile substances degraded during alkali treatment. This leads to a conclusion that alkali treatment of rice husks with more than 4% NaOH causes a substantial chemical degradation of rice husks, which subsequently decreases their thermal stability.

  5. Cost-benefit analysis of replacing maize with rice husk ...

    Cost-benefit analysis of replacing maize with rice husk supplemented with grindazyme, nutrsea ... Log in or Register to get access to full text downloads. ... Rice husk was added at the expense of maize in the control diet and each experimental ...

  6. The Effect of Commercial Rice Husk Ash Additives on the Porosity, Mechanical Properties, and Microstructure of Alumina Ceramics

    Mohammed Sabah Ali; M.A. Azmah Hanim; S. M. Tahir; C. N.A. Jaafar; Norkhairunnisa Mazlan; Khamirul Amin Matori


    A porous ceramic is made from composite materials which consist of alumina and commercial rice husk ash. This type of ceramics is obtained by mixing the commercial rice husk ash as a source of silica (SiO2) and a pore forming agent with alumina (Al2O3) powder. To obtain this type of ceramic, a solid-state technique is used with sintering at high temperature. This study also investigated the effects of the rice husk ash ratios on the mechanical properties, porosity, and microstructure. The res...

  7. Mechanical properties of rice husk flour reinforced epoxy biocomposite

    Neeraj Bisht


    Full Text Available A bio-composite reinforced with rice husk flour in epoxy resin has been developed. The effect of fibre treatment and weight percentage of rice husk on the mechanical properties was studied and compared with wood dust reinforced epoxy composite. It was observed that addition of rice husk as filler is detrimental to almost all the mechanical properties. About 51% and 26.8% decrease in ultimate strength and Young’s Modulus for 40 wt% untreated rice husk reinforcement was observed. The corresponding decrease in flexural strength and flexural modulus was 51%. Similar trend was also observed in hardness and impact strength. However the mechanical properties of rice husk reinforced biocomposites are found to be superior than wood dust reinforced epoxy composite. SEM microscopy was also done to corroborate the results.

  8. Conversion of rice husk ash to zeolite beta.

    Prasetyoko, Didik; Ramli, Zainab; Endud, Salasiah; Hamdan, Halimaton; Sulikowski, Bogdan


    White rice husk ash (RHA), an agriculture waste containing crystalline tridymite and alpha-cristobalite, was used as a silica source for zeolite Beta synthesis. The crystallization of zeolite Beta from RHA at 150 degrees C in the presence of tetraethylammonium hydroxide was monitored by XRD, FTIR and (29)Si MAS NMR techniques. It was found that zeolite Beta started to form after 12h and the complete crystallization of zeolite Beta phase was achieved after 2d. XRD, (29)Si MAS NMR and solid yield studies indicate that the transformation mechanism of silica present in RHA to zeolite Beta involves dissolution of the ash, formation of an amorphous aluminosilicate after 6h of crystallization, followed by dissolution in the mother liquor and final transformation to pure zeolite Beta crystals.

  9. Evaluation of the occluded carbon within husk phytoliths of 35 rice cultivars

    Sun, Xing; Liu, Qin; Gu, Jie; Chen, Xiang; Zhu, Keya


    Rice is a well-known silicon accumulator. During its periods of growth, a great number of phytoliths are formed by taking up silica via the plant roots. Concurrently, carbon in those phytoliths is sequestrated by a mechanism of long-term biogeochemical processes within the plant. Phytolith occluded C (PhytOC) is very stable and can be retained in soil for longer than a millennium. In this study, we evaluated the carbon biosequestration within the phytoliths produced in rice seed husks of 35 rice cultivars, with the goal of finding rice cultivars with relatively higher phytolith carbon sequestration efficiencies. The results showed that the phytolith contents ranged from 71.6 mg•g‒1 to 150.1 mg•g‒1, and the PhytOC contents ranged from 6.4 mg•g‒1 to 38.4 mg•g‒1, suggesting that there was no direct correlation between the PhytOC content and the content of rice seed husk phytoliths ( R = 0.092, p>0.05). Of all rice cultivars, six showed a higher carbon sequestration efficiency in phytolith seed husks. Additionally, the carbon biosequestration within the rice seed husk phytoliths was approximately 0.45‒3.46 kg-e-CO2•ha‒1•yr‒1. These rates indicate that rice cultivars are a potential source of carbon biosequestration which could contribute to the global carbon cycle and climate change.

  10. [Adsorption mechanism of furfural onto modified rice husk charcoals].

    Deng, Yong; Wang, Xianhua; Li, Yunchao; Shao, Jing'ai; Yang, Haiping; Chen, Hanping


    To evaluate the absorptive characteristics of furfural onto biomass charcoals derived from rice husk pyrolysis, we studied the information of the structure and surface chemistry properties of the rice husk charcoals modified by thermal treatment under nitrogen and carbon dioxide flow and adsorption mechanism of furfural. The modified samples are labeled as RH-N2 and RH-CO2. Fresh rice husk charcoal sample (RH-450) and modified samples were characterized by elemental analysis, nitrogen adsorption-desorption isotherms, Fourier-transform infrared spectroscopy and Boehm titration. The results show that fresh rice husk charcoal obtained at 450 degrees C had a large number of organic groups on its surface and poor pore structure. After the modification under nitrogen and carbon dioxide flow, oxygenic organics in rice husk charcoals decompose further, leading to the reduction of acidic functional groups on charcoals surface, and the increase of the pyrone structures of the basic groups. Meanwhile, pore structure was improved significantly and the surface area was increased, especially for the micropores. This resulted in the increase of π-π dispersion between the surfaces of rice husk charcoals and furfural molecular. With making comprehensive consideration of π-π dispersion and pore structure, the best removal efficiency of furfural was obtained by rice husk charcoal modified under carbon dioxide flow.

  11. Thermoelectric properties and nanostructures of materials prepared from rice husk ash

    Pukird, S.; Tipparach, U.; Kasian, P. [Ubon Ratchathani Univ., Ubon Ratchathani (Thailand). Dept. of Physics; Limsuwan, P. [King Mongkut' s Univ. of Technology Thonburi, Bangkok (Thailand). Dept. of Physics


    Thailand produces large amounts of agricultural residues such as rice husk and coconut shells. Rice husk is considered to be a potential source for solar grade silicon. Studies have shown that reasonably pure polycrystalline silicon can be prepared from rice husk white ash by a metallothermic reduction process. This paper reported on a study that investigated the thermoelectric properties of ceramic material prepared by mixing silica from rice husk ash and carbon obtained from coconut shell charcoal. The thermoelectric properties of the materials were examined along with their microstructures. The materials were made from burning rice husk ash and coconut shell at different temperatures and then doped with metal oxides. Pellets were heated at temperature of 700 degrees C for 1-3 hours. The voltage on both sides of the pellets was observed. The electromotive force was found when different temperatures were applied on both sides of the pellet specimens. The Seebeck coefficient was then calculated. The results showed that these materials can be used as thermoelectric devices. Scanning electron microscope (SEM) and energy dispersive X-rays (EDX) were used to investigate the source of materials and the products on the substrates. The images of SEM and EDX showed nanostructures of materials such as nanowires, nanorods and nanoparticles of the products and sources. 22 refs., 2 tabs., 9 figs.

  12. A Simple Method of Obtaining Spherical Nanosilica from Rice Husk

    Mohammed Noushad


    Full Text Available This paper describes the synthesis of nanosilica from rice husk. Synthesis was done by precipitation using different acids, namely, orthophosphoric acid and nitric acid which yielded nanosilica. The effect of different acids and different solvents (polar and non-polar on the size and degree of agglomeration of the silica particles were studied. When precipitation was done without the use of solvents, the silica particles  obtained were non-spherical in shape, whereas, when precipitation was done using polar solvents (ethanol or 2-propanol, the silica particles were spherical. The use of non-polar solvents (toluene and diethyl ether resulted in silica particles that were irregular in shape and in the case of orthophosphoric acid, a high degree of agglomeration was also noted. The degree of agglomeration was less when orthophosphoric acid was used with polar solvents as compared to nitric acid in conjunction with polar solvents. As regards the size, it ranged from approximately 70nm to 400nm when either acid was used in conjunction with polar solvents. When non-polar solvents were used, the silica particles were irregular in shape and the particle size was not estimated.

  13. Obtenção de mulita porosa a partir da sílica da casca de arroz e do acetato de alumínio Porous mullite obtained using silica from rice husk and aluminum acetate

    R. R. Menezes


    Full Text Available O grande volume de produção de arroz no mundo gera uma enorme quantidade de rejeito na forma de cascas e de cinzas oriundas da queima da casca. Esses resíduos são fontes de poluição e contaminação, podendo agredir diretamente a saúde da população. Assim, esse trabalho tem por objetivo a obtenção de mulita porosa a partir da sílica da casca de arroz e do acetato de alumínio. O resíduo foi física e quimicamente caracterizado e em seguida misturado com acetato de alumínio para a produção do precursor da mulita. O material precursor foi caracterizado termicamente e com base nos resultados foi calcinado a 850 ºC e 1200 ºC. Os corpos de prova foram queimados a 1500 ºC e 1600 ºC e caracterizados pela determinação de sua porosidade aparente, absorção de água e densidade aparente e por difração de raios X e microscopia eletrônica de varredura. Os resultados indicaram que a sílica é constituída por material amorfo e aglomerados micrométricos de partículas submicrométricas e nanométricas. Com base nos resultados conclui-se que a sílica obtida da casca de arroz e o acetato de alumínio podem ser utilizados com sucesso para a produção de corpos mulíticos porosos com porosidades superiores a 48%.The production of rice around the world generates large amounts of waste in the form of husks and ashes from husks burning, which are sources of environmental contamination and pollution. The aim of this work was obtain porous mullite bodies using the silica from the rice husk and aluminum acetate. The waste material was physically and chemically characterized. The mullite precursor was produced mixing the waste and aluminum acetate. The thermal behavior of mullite precursor was described. The precursor was fired at 850 ºC and 1200 ºC and sample bodies were sintered at 1500 and 1600 ºC. Sintered samples were characterized to determine their apparent porosity, water absorption, apparent density, and microstructurally

  14. influence of addition of rice husk ash on porcelain composition

    Porcelain powder was grounded separately in a ball mill. The powder was sieved using ... The mixed powder .... combustion at 7000C produces a very good reactive material. The .... rice husk-berk ash on mechanical properties of of concrete.

  15. Concrete with Highly Active Rice Husk Ash

    FENG Qing-ge; LIN Qing-yu; YU Qi-jun; ZHAO San-ying; YANG Lu-feng; Shuichi Sugita


    The overall aim was to investigate the effect of highly active rice husk ash (RHA) produced by an industrial furnace on some properties of concrete. The strength, pore volume and pore distribution of concrete and the Ca(OH)2 content in concrete were investigated by JIS A 1108 (Method of test for compressive strength of concrete), a mercury instrument porosimeter, and the thermogravimetric analysis, respectively. The results show that,with RHA replacement of cement,the compressive strength of concrete is increased evidently;the average pore radius of concrete is greatly decreased, especially the portion of the pores greater than 20nm in radius is decreased while the amount of smaller pores is increased, and the more the RHA replacement, the less the amount of Ca(OH)2 in concrete. The latter two results are the main reasons for the strength enhancement of concrete.

  16. Synthesis and surface characteristics of nanosilica produced from alkali-extracted rice husk ash

    Liou, Tzong-Horng, E-mail: [Department of Chemical Engineering, Ming Chi University of Technology, 84 Gungjuan Rd., Taipei 24301, Taiwan (China); Yang, Chun-Chen [Department of Chemical Engineering, Ming Chi University of Technology, 84 Gungjuan Rd., Taipei 24301, Taiwan (China)


    Rice husk is a form of agricultural biomass that provides an abundant silicon source. This study used rice husk as a raw material to prepare nanosilica without adding an extra surfactant. This work investigated a dissolution-precipitation technique as a function of acid treatment, sodium silicate concentration, gelation pH, aging temperature, and aging time to establish optimum conditions for preparing silica nanoparticles. Experimental results showed that silica produced by hydrochloric acid possesses higher surface area than that of sulfuric, oxalic, and citric acids. Surface characteristics of the sample depend mainly upon gelation pH. The highest surface area and pore volume of silica samples were 634 m{sup 2}/g and 0.811 cm{sup 3}/g. Pore diameters were controllable from 3 to 9 nm by adjusting the solution pH value. Particles had a uniform size of 5-30 nm. The objective of this study was to develop a method of nanosilica preparation that enhances the economic benefits of re-using rice husk waste.

  17. Utilization of Rice Husk Ash for Sustainable Construction: A Review

    M.N.N. Khan


    Full Text Available Applications of Supplementary Cementitious Materials (SCM in construction industry are getting priority due to environmental friendly behavior as well as enhanced mechanical and durability properties. Considering the characteristics of SCM, properly burnt and ground Rice Husk Ash (RHA has significant potential on account of rich reactive silica (SiO2 compound. When RHA is applied in cementitious system it improves the systems properties by two fold of effects; chemical or pozzlanic effect and physical or filler effect. The reactive silica compound present in RHA reacts with cement hydration products calcium hydroxide (Ca (OH2 and formed secondary C-S-H gel, which is counted as chemical or pozzolanic activity of RHA. The physical or filler effect of RHA is denoted as the proper distribution of finer RHA particles into the cementitious system. This study reviews the advantageous use of RHA for sustainable construction. The aim of this study is to promote the idea of using RHA by elaborating upon their various production processes, different properties, pozzolanic activity and its contribution to the cementitious system.

  18. Pyrolysis of rice husk and sawdust for liquid fuel


    The paper is focused on studying how to convert rice husk and sawdust into liquid fuel. Rice husk, sawdust and their mixture were pyrolyzed at the temperature between 420℃ and 540℃, and the main product of liquid fuel was obtained. The experimental result showed that the yield of liquid fuel heavily depended on the kind of feedstock and pyrolysis temperature. In the experiments, the maximum liquid yields for rice husk, sawdust and their mixture were 56% at 465℃, 61% at 490℃ and 60% at 475℃respectively. Analysis with GC-MS and other apparatus indicated that the liquid fuel is a complicated organic compound with low caloric value and can be directly used as fuel oil without any up-grading. As a crude oil, the liquid fuel can be refined to be vehicle oil.

  19. Removal of copper (II) ion from aqueous solution using zeolite Y synthesized from rice husk ash: Equilibrium and kinetic study

    Tuyen, Nguyen Thi Kim; Nhan, Do Nguyen Thanh; Nhat, Trieu Thi; An, Ngo Thanh; Long, Nguyen Quang


    Zeolite Y was synthesized from silica of rice-husk ash using hydrothermal process. The crystalline structure FAU of zeolite Y was characterized by X-ray diffraction (XRD). Surface's area of the catalyst was determined by physic-adsorption method using BET model. The zeolite was examined for possibility of Cu2+ adsorbent by an ion-exchange mechanism. Various adsorption isotherm models, such as Langmuir, Freundlich and Dubinin-Radushkevich were tested for equilibrium study. The integration method was applied to find out the possible kinetic equation of the Cu2+ adsorption on the zeolite Y which obtained from cheap and locally available rice husk ash.

  20. Hydrothermal and mechanochemical reactions of rice husk ash with calcium hydroxide

    Sugita, S.; Isojima, Y. [Hachinohe Institute of Technology, Aomori (Japan); Yu, Q. [Wuhan University of Technology, (Taiwan, Province of China)


    It is well known that a calcium silicate hydrate, commonly referred to as C-S-H gel, is important for cement to exhibit strength. Silica is present in rice husk ash to around 90%. When sufficiently sintered and crushed, rice husk ash mostly comprises amorphous silica having a large surface area. It is reactive, and is considered to contribute to improvement of concrete strength and durability. In this study, rice husk ash is reacted with calcium hydroxide under hydrothermal conditions or mechanochemical conditions at normal temperature, to synthesize Ca(1.5)SiO(3.5){center_dot}xH2O as one of the calcium silicate hydrates. It has an average particle size of 10{mu}m or smaller, which varies depending on synthesis method and condition. The compound synthesized at 40degC is composed of flocs having a porous structure and large specific surface area, as is the case with a C-S-H gel present in Portland cement paste. It loses the above structure and moisture in the fine pores gradually, when heated, but remains amorphous at up to 750degC. It is transformed into wollastonite, when heated to 780degC. 7 refs., 8 figs., 3 tabs.

  1. Adsorption of lead and copper ions from aqueous effluents on rice husk ash in a dynamic system

    M. G. A. Vieira


    Full Text Available This study evaluated the kinetic adsorption of Pb and Cu ions using rice husk ash as adsorbent in a fixed bed. The maximum adsorption capacities obtained for lead and copper ions in the fixed bed were 0.0561 and 0.0682 mmol/g (at 20 ºC, respectively. The thermodynamic studies indicated that the lead adsorption process was exothermic and spontaneous, while the copper adsorption process was endothermic and spontaneous. Characterization results indicated the presence of several functional groups, amorphous silica and a fibrous and longitudinal structure of rice husks. Rice husk ash (RHA from northern Brazil can be used as a bioadsorbent for the individual removal of Pb(II and Cu(II ions from metal-containing effluents.

  2. Removal of arsenic from drinking water using rice husk

    Asif, Zunaira; Chen, Zhi


    Rice husk adsorption column method has proved to be a promising solution for arsenic (As) removal over the other conventional methods. The present work investigates the potential of raw rice husk as an adsorbent for the removal of arsenic [As(V)] from drinking water. Effects of various operating parameters such as diameter of column, bed height, flow rate, initial arsenic feed concentration and particle size were investigated using continuous fixed bed column to check the removal efficiency of arsenic. This method shows maximum removal of As, i.e., 90.7 % under the following conditions: rice husk amount 42.5 g; 7 mL/min flow rate in 5 cm diameter column at the bed height of 28 cm for 15 ppb inlet feed concentration. Removal efficiency was increased from 83.4 to 90.7 % by reducing the particle size from 1.18 mm to 710 µm for 15 ppb concentration. Langmuir and Freundlich isotherm models were employed to discuss the adsorption behavior. The effect of different operating parameters on the column adsorption was determined using breakthrough curves. In the present study, three kinetic models Adam-Bohart, Thomas and Yoon-Nelson were applied to find out the saturated concentration, fixed bed adsorption capacity and time required for 50 % adsorbate breakthrough, respectively. At the end, solidification was done for disposal of rice husk.

  3. Characterization of materials formed by rice husk for construction

    Portillo-Rodríguez, A. M.


    This review article delves into the use of agro-industrial wastes, which in construction field provides alternatives for environmental problems with the use of them. This fact enables development and lower costs for new options in the brick, cluster, mortar and concrete industry, what represents benefits for environment, housing and generally everything related to construction, looking for sustainability. For that reason a literature review is made to support the theme focusing on the use of rice husk in its natural, ground or ash state for manufacturing elements with clay masonry, precast and optimization of concrete and mortars. The technique used is based on scientific articles and researches found in reliable databases that were analyzed and integrated into a synthesized structure, which summarized the objectives, analysis processes, the physical and mechanical properties and finally the results. The conclusions are focused on potentiality of elements production in the construction development based on the high effectiveness like thermal insulation, low density and various benefits offered by high silica content pozzolanic properties, etc.

  4. Pozzolanic Characterization Of Waste Rice Husk Ash (RHA) From Muar, Malaysia

    Hadipramana, J.; Riza, F. V.; Rahman, I. A.; Loon, L. Y.; Adnan, S. H.; Zaidi, A. M. A.


    Investigation of Rice Husk Ash (RHA) thoroughly under controlled burning is regular issue to obtain result to produce the amorphous silica that has high pozzolanic reactivity characteristic. This paper offered an observation about characteristic of ground and un-ground of un-controlled burning temperature RHA that were taken from rice millings in Muar, Johor Malaysia. Such tests as X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Particle Size Analysis and Specific Area Surface, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron microscope (SEM) were conducted in this investigation to carry out the characteristic of RHA samples. The results show that the RHA was consist approximately 89.90% of silica and the RHA possessed the amorphous particle were dominant than its crystalline part. This proves that the RHA has a big potential as a pozzolanic material considering the silica content and porous structure. In addition, particle size analysis decides whether the pozzolanic reactivity can be increased by grinding process.

  5. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    Taha, Mohd F., E-mail:; Shaharun, Maizatul S. [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Perak Darul Ridzuan (Malaysia); Shuib, Anis Suhaila, E-mail:; Borhan, Azry [Chemical Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Perak Darul Ridzuan (Malaysia)


    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m{sup 2}/g and 0.17 cm{sup 2}/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  6. 气相、沉淀、稻壳SiO2/聚乙烯醇复合膜的性能比较%Comparative Study of Performance of Fume, Precipitate and Rice Husk Silica Filled Polyvinyl Alcohol Hybrid Membranes

    石红; 刘学清


    This paper first compared the physical properties of fume, precipitate and rice husk silica. The tensile properties and water risistance of polyvinyl alcohoKPVA) filled with these silica were studied with respect to filler loading and filler type. Results showed that,at the same filler loading,elongation at breaking and tensile strength of membranes changed in the following order:fume SiO2/PVA> rice husk SiO2/PVA >pre-cipitate SiO2/PVA. Tensile modulus changed in the following order:fume SiO2/PVA> precipitate SiO2/PVA > rice husk SiO2/PVA. In addition,three sources of silica all could enhance the water resistance of PVA, which increased with the silica content. At the same filler loading, the water resistance of membranes changed in the following order:fume SiO2/PVA> precipitate SiO2/PVA> rice husk SiO2/PVA.%分别采用气相SiO2、沉淀SiO2和稻壳SiO2与聚乙烯醇(PVA)按不同的比例制备成复合膜.比较了3种不同来源的纳米SiO2/PVA复合膜的拉伸性能及耐水性能.结果表明:SiO2含量相同时,复合膜的断裂伸长率和拉伸强度的排列顺序为:气相SiO2/PVA>稻壳SiO2/PVA>沉淀SiO2/PVA;拉伸模量的排列顺序为:气相SiO2/PVA>沉淀SiO2/PVA>稻壳SiO2/PVA;3种来源的SiO2都可以提高PVA的耐水性,且耐水性随SiO2含量的增大而增强,SiO2含量相同时,复合膜的耐水性排列顺序为:气相SiO2/PVA>沉淀SiO2/PVA>稻壳SiO2/PVA.

  7. Study on concrete with partial replacement of cement by rice husk ash

    Kaarthik Krishna, N.; Sandeep, S.; Mini, K. M.


    Increase in the demand of conventional construction materials and the need for providing a sustainable growth in the construction field has prompted the designers and developers to opt for ‘alternative materials’ feasible for use in construction. For this objective, the use of industrial waste products and agricultural byproducts are very constructive. These industrial wastes and agricultural by products such as Fly Ash, Rice Husk Ash, Silica Fume, and Slag can be replaced instead of cement because of their pozzolanic behavior, which otherwise requires large tract of lands for dumping. In the present investigation, Rice Husk Ash has been used as an admixture to cement in concrete and its properties has been studied. An attempt was also done to examine the strength and workability parameters of concrete. For normal concrete, mix design is done based on Indian Standard (IS) method and taking this as reference, mix design has been made for replacement of Rice Husk Ash. Four different replacement levels namely 5%, 10%, 15% and 20% are selected and studied with respect to the replacement method.

  8. Design and modeling of a novel continuous open core downdraft rice husk gasifier

    Manurung, Robert


    Rice husk is one of the most widely available agricultural wastes in many rice producing countries around the world. Conversion of the abundant supply of rice husk into clean energy is an opportunity to expand the energy resource base while reducing the environmental burden now associated with the d

  9. The Effect of Commercial Rice Husk Ash Additives on the Porosity, Mechanical Properties, and Microstructure of Alumina Ceramics

    Mohammed Sabah Ali


    Full Text Available A porous ceramic is made from composite materials which consist of alumina and commercial rice husk ash. This type of ceramics is obtained by mixing the commercial rice husk ash as a source of silica (SiO2 and a pore forming agent with alumina (Al2O3 powder. To obtain this type of ceramic, a solid-state technique is used with sintering at high temperature. This study also investigated the effects of the rice husk ash ratios on the mechanical properties, porosity, and microstructure. The results showed that, by increasing the content of the rice husk ash from 10 to 50 wt%, there is an increase in the porosity from 42.92% to 49.04%, while the mechanical properties decreased initially followed by an increase at 30 wt% and 50 wt%; the hardness at 20 wt% of the ash content was recorded at 101.90 HV1. When the ash content was increased to 30 wt% and 50 wt%, the hardness was raised to 150.92 HV1 and 158.93 HV1, respectively. The findings also revealed that the tensile and compressive strengths experienced a decrease at 10 wt% of the ash content and after that increase at 30 wt% and 50 wt% of rice husk ash. XRD analysis found multiple phases of ceramic formation after sintering for the different rice husk ash content.

  10. Energy Efficient Dryer with Rice Husk Fuel for Agriculture Drying

    M. Djaeni


    Full Text Available Energy usage is crucial aspect on agriculture drying process. This step spends about 70% of total energy in post harvest treatment. The design of efficient dryer with renewable energy source is urgently required due to the limitation of fossil fuel energy. This work discusses the performance of air dehumidification using rice husk fuel as heat source for onion, and paddy drying. Unlike conventional dryer, the humidity of air during the drying was dehumidified by adsorbent. Hence, the driving force of drying can be  kept high.  As consequences, the drying time and energy usage can be reduced. Here, the research was conducted in two step: laboratory and pilot scale tests. Results showed that the lowering air humidity with rice husk fuel has improved the energy efficiency. At operational temperature 60oC, the heat efficiency of 75%  was achieved. 


    K. Hardinnawirda


    Full Text Available In this study, rice husk-filled polyester composites were produced with rice husks (RH as the filler and unsaturated polyester resin (UPR as the matrix. Several percentages of filler loadings were used (10, 15, 20 and 25 wt % in order to gain insights into the effect of filler content on the mechanical properties and water intake of the composites. The tensile strength of the RH-filled UPR composites was found to decrease as the filler loading increased; however, as it reached 25 wt %, the strength showed a moderate increase. The Young’s modulus showed a remarkable increase for 15 wt % of RH but decreased as the RH percentage increased further to 25 wt %. A water absorption test was conducted and the results showed that the composites absorb more water as the percentage weight of RH increased, which is attributed to the ability of the RH filler to absorb water.

  12. Evaluation of Heavy Metals Contamination from Environment to Food Matrix by TXRF: The Case of Rice and Rice Husk

    Fabjola Bilo


    Full Text Available This paper is devoted to the chemical analysis of contaminated soils of India and the rice grown in the same area. Total reflection X-ray fluorescence spectroscopy is a well-established technique for elemental chemical analysis of environmental samples, and it can be a useful tool to assess food safety. Metals uptake in rice crop grown in soils from different areas was studied. In this work soil, rice husk and rice samples were analyzed after complete solubilization of samples by microwave acid digestion. Heavy metals concentration detected in rice samples decreases in the following order: Mn > Zn > Cu > Ni > Pb > Cr. The metal content in rice husk was higher than in rice. This study suggests, for the first time, a possible role of heavy metals filter played by rice husk. The knowledge of metals sequestration capability of rice husk may promote some new management practices for rice cultivation to preserve it from pollution.

  13. Ultrasonic and conventional synthesis of NaA zeolite from rice husk ash

    Farías, T.; de Ménorval, LC; Picazo, O.; Jordán, R.


    In the present work, a simple synthetic route for the production of single phase NaA zeolite is demonstrated. Rice husk ash (RHA) as alternative silica source was employed for the synthesis by conventional hydrothermal and non-conventional ultrasound methods. The zeolite was also synthesized using commercially available silicate for comparison. The effect of the reaction time (2, 4 and 6 h) at a fixed temperature of 70 °C was investigated. The elemental, structural and morphological characterization of the ashes and the synthesized zeolites was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TG/DSC).

  14. Rice husk ash as a renewable source for the production of zeolite NaY and its characterization

    R.M. Mohamed


    Full Text Available Zeolite Y in sodium form (NaY was synthesized using silica source from rice husk. The as-synthesized samples were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, X-ray fluorescence (XRF, BET. As results, we verify that NaY zeolite obtained from the two-step route, presents a good degree of crystallinity and then can be suitable for using in various applications.

  15. Alkaline peroxide assisted wet air oxidation pretreatment approach to enhance enzymatic convertibility of rice husk.

    Banerjee, Saumita; Sen, Ramkrishna; Mudliar, Sandeep; Pandey, R A; Chakrabarti, Tapan; Satpute, Dewanand


    Pretreatment of rice husk by alkaline peroxide assisted wet air oxidation (APAWAO) approach was investigated with the aim to enhance the enzymatic convertibility of cellulose in pretreated rice husk. Rice husk was presoaked overnight in 1% (w/v) H(2)O(2) solution (pH adjusted to 11.5 using NaOH) (equivalent to 16.67 g H(2)O(2) and 3.63 g NaOH per 100 g dry, untreated rice husk) at room temperature, followed by wet air oxidation (WAO). APAWAO pretreatment resulted in solubilization of 67 wt % of hemicellulose and 88 wt % of lignin initially present in raw rice husk. Some amount of oligomeric glucose (˜8.3 g/L) was also observed in the APAWAO liquid fraction. APAWAO pretreatment resulted in 13-fold increase in the amount of glucose that could be obtained from otherwise untreated rice husk. Up to 86 wt % of cellulose in the pretreated rice husk (solid fraction) could be converted into glucose within 24 hours, yielding over 21 g glucose per 100 g original rice husk. Scanning electron microscopy was performed to visualize changes in biomass structure following the APAWAO pretreatment. Enzymatic cellulose convertibility of the pretreated slurry at high dry matter loadings was also investigated.

  16. Experimental Investigation of Thermal Characteristics of Kiwira Coal Waste with Rice Husk Blends for Gasification

    Deodatus Kazawadi


    Full Text Available Eminent depletion of fossil fuels and environmental pollution are the key forces driving the implementation cofiring of fossil fuels and biomass. Cogasification as a technology is known to have advantages of low cost, high energy recovery, and environmental friendliness. The performance/efficiency of this energy recovery process substantially depends on thermal properties of the fuel. This paper presents experimental study of thermal behavior of Kiwira coal waste/rice husks blends. Compositions of 0, 20, 40, 60, 80, and 100% weight percentage rice husk were studied using thermogravimetric analyzer at the heating rate of 10 K/min to 1273 K. Specifically, degradation rate, conversion rate, and kinetic parameters have been studied. Thermal stability of coal waste was found to be higher than that of rice husks. In addition, thermal stability of coal waste/rice husk blend was found to decrease with an increase of rice husks. In contrast, both the degradation and devolatilization rates increased with the amount of rice husk. On the other hand, the activation energy dramatically reduced from 131 kJ/mol at 0% rice husks to 75 kJ/mol at 100% rice husks. The reduction of activation energy is advantageous as it can be used to design efficient performance and cost effective cogasification process.

  17. Influence of Pyrolysis Temperature on Rice Husk Char Characteristics and Its Tar Adsorption Capability

    Anchan Paethanom


    Full Text Available A biomass waste, rice husk, was inspected by thermoanalytical investigation to evaluate its capability as an adsorbent medium for tar removal. The pyrolysis process has been applied to the rice husk material at different temperatures 600, 800 and 1000 °C with 20 °C/min heating rate, to investigate two topics: (1 influence of temperature on characterization of rice husk char and; (2 adsorption capability of rice husk char for tar removal. The results showed that subsequent to high temperature pyrolysis, rice husk char became a highly porous material, which was suitable as tar removal adsorbent with the ability to remove tar effectively. In addition, char characteristics and tar removal ability were significantly influenced by the pyrolysis temperature.

  18. Effect of recycling on properties of rice husk-filled-polypropylene

    Jutarat Prachayawarakorn


    Full Text Available This research concerned with the use of rice husk (Oryza sativa as a filler for polypropylene and its recycle ability. Rice husk (200 mesh and 40% by weight and polypropylene were compounded in a twinscrew extruder and injection moulding technique was applied in order to obtain testing specimens. It was found that tensile, flexural and impact properties as well as % water absorption of the rice husk-filled polypropylene were only slightly dropped upon recycling process, presenting the ability of the rice husk- filledpolypropylene samples to recycle. The increase in melt flow index of the samples was also obtained. In addition, SEM micrographs revealed the reduction of rice husk particle size by the recycling process. Moreover, FTIR spectroscopy and TGA technique were performed for characterizing the filled specimens.

  19. Magnesiothermic reduction of rice husk ash for electromagnetic wave adsorption

    Liu, Shu-Ting; Yan, Kang-kang; Zhang, Yuan hu; Jin, Shi-di; Ye, Ying; Chen, Xue-Gang, E-mail:


    The increase in electromagnetic pollution due to the extensive exploitation of electromagnetic (EM) waves in modern technology creates correspondingly urgent need for developing effective EM wave absorbers. In this study, we carried out the magnesiothermic reduced the rice husk ash under different temperatures (400–800 °C) and investigated the electromagnetic wave adsorption of the products. The EM absorbing for all samples are mainly depend on the dielectric loss, which is ascribed to the carbon and silicon carbide content. RA samples (raw rice husk ashed in air and was magesiothermic reduced in different temperatures) exhibit poor dielectric properties, whereas RN samples (raw rice husk ashed in nitrogen and was magesiothermic reduced in different temperatures) with higher content of carbon and silicon carbide display considerable higher dielectric loss values and broader bandwidth for RL<−5 dB and −10 dB. For RN samples, the maximum bandwidth for −5 dB and −10 dB decrease with carbon contents, while the optimum thickness decrease with increasing SiC content. The optimum thickness of RN400–800 for EM absorption is 1.5–2.0 mm, with maximum RL of between −28.9 and −68.4 dB, bandwidth of 6.7–13 GHz for RL<−5 dB and 3.2–6.2 GHz for RL<−10 dB. The magnesiothermic reduction will enhance the potential application of rice husk ash in EM wave absorption and the samples benefited from low bulk density and low thickness. With the advantages of light-weight, high EM wave absorption, low cost, RN400–800 could be promising candidates for light-weight EM wave absorption materials over many conventional EM wave absorbers. - Highlights: • RN400–800 samples are potential light-weight electromagnetic absorbers. • Carbon and SiC are considered as dominating contributions for the dielectric loss. • Magnesiumothermic reduction extends the EM wave absorption potential of RHN.

  20. Electricity production potential and social benefits from rice husk, a case study in Pakistan

    Obaidullah Mohiuddin


    Full Text Available Pakistan has been experiencing energy crisis owing to its sole dependence on fossil fuels. Reduction in local fossil fuel reserves has led to an increase in their prices, thereby increasing the cost of electricity. Since the tariff remains the same, Pakistan is over-burdened with circular debts and observes a daily power shortfall of about 12–14 h. Being an Agra-economic country, many major and minor crops are produced and exported in large quantities. This results in a bulk of the agricultural waste which are not utilized. The waste can be utilized to meet the country’s energy demand while mitigating climate change and its impact. The study examines the electricity production potential and social benefits of rice husk in Pakistan. It is estimated in this study that if 70% of rice husk residues are utilized, there will be annual electricity production of 1,328 GWh and the cost of per unit electricity by rice husk is found at 47.36 cents/kWh as compared to 55.22 cents/kWh of electricity generated by coal. Importantly, the study will increase the awareness of the benefits of utilizing agricultural waste for useful products such as silica, with several social and environmental benefits such as a reduction of 36,042 tCO2e/yr of methane, reducing carbon dioxide emissions, improving the air quality, and providing 4.5 k new jobs. The paper concludes with the policy recommendations based on this study.

  1. Environmentally-Friendly Dense and Porous Geopolymers Using Fly Ash and Rice Husk Ash as Raw Materials

    Daniele Ziegler


    Full Text Available This paper assesses the feasibility of two industrial wastes, fly ash (FA and rice husk ash (RHA, as raw materials for the production of geopolymeric pastes. Three typologies of samples were thus produced: (i halloysite activated with potassium hydroxide and nanosilica, used as the reference sample (HL-S; (ii halloysite activated with rice husk ash dissolved into KOH solution (HL-R; (iii FA activated with the alkaline solution realized with the rice husk ash (FA-R. Dense and porous samples were produced and characterized in terms of mechanical properties and environmental impact. The flexural and compressive strength of HL-R reached about 9 and 43 MPa, respectively. On the contrary, the compressive strength of FA-R is significantly lower than the HL-R one, in spite of a comparable flexural strength being reached. However, when porous samples are concerned, FA-R shows comparable or even higher strength than HL-R. Thus, the current results show that RHA is a valuable alternative to silica nanopowder to prepare the activator solution, to be used either with calcined clay and fly ash feedstock materials. Finally, a preliminary evaluation of the global warming potential (GWP was performed for the three investigated formulations. With the mix containing FA and RHA-based silica solution, a reduction of about 90% of GWP was achieved with respect to the values obtained for the reference formulation.

  2. Stability studies of immobilized lipase on rice husk and eggshell membrane

    Abdulla, R.; Sanny, S. A.; Derman, E.


    Lipase immobilization for biodiesel production is gaining importance day by day. In this study, lipase from Burkholderia cepacia was immobilized on activated support materials namely rice husk and egg shell membrane. Both rice husk and eggshell membrane are natural wastes that holds a lot of potential as immobilization matrix. Rice husk and eggshell membrane were activated with glutaraldehyde. Lipase was immobilized on the glutaraldehyde-activated support material through adsorption. Immobilization efficiency together with enzyme activity was observed to choose the highest enzyme loading for further stability studies. Immobilization efficiency of lipase on rice husk was 81 as compared to an immobilization efficiency of 87 on eggshell membrane. Immobilized lipase on eggshell membrane exhibited higher enzyme activity as compared to immobilized lipase on rice husk. Eggshell membrane also reported higher stability than rice husk as immobilization matrix. Both types of immobilized lipase retatined its activity after ten cycles of reuse. In short, eggshell membrane showed to be a better immobilization platform for lipase as compared to rice husk. However, with further improvement in technique of immobilization, the stability of both types of immobilized lipase can be improved to a greater extent.

  3. Rice husk ash as corrective of soil acidity

    Gláucia Oliveira Islabão


    Full Text Available Rice husk ash (RHA is a by-product from the burning of rice husk that can have favorable effects on the soil in terms of acidity correction. The objectives of this study were to determine the effective calcium carbonate equivalent (ECC of RHA under field conditions, and establish technical criteria as a basis for estimating the overall ECC of RHA. The 12 treatments of the experiment consisted of 10 RHA dosages (0, 10, 20, 30, 40, 60, 80, 100, 120, and 140 Mg ha-1 and two references, one of which was an absolute control (AC and the other a plot limed and fertilized according to official recommendations (recommended fertilization - RF. The soil was sampled twice (15 and 210 days after incorporating RHA, in the layers 0.00-0.10 and 0.10-0.20 m, to determine the pH(H2O and base saturation (V%. The ECC and neutralizing value (NV of RHA were also determined. The results showed that RHA neutralizes soil acidity, in a faster reaction than conventional limestone, despite a low ECC (around 3 %.

  4. Property Optimization of Kaolin-Rice Husk Insulating Fire Bricks

    E.O.Onche; B.I.Ugheoke; G.A.Asikpo


    In this work, the suitability of using Kaolin-Rice husk-plastic clay to produce insulating firebrick was experimentally investigated and the optimal ratio of these constituents determined. Ten brick samples of different compositions were fired at 1200℃. Three of the samples(samples 6, 7, and 8) crumbled during firing. The surviving samples gave the following limits of results:shrinkage: 9.7% - 13.6%; effective moisture content:28. 34% -32.52%; modulus of rupture: 4.26kgf/cm2 - 19. 10kgf/cm2; apparent porosity: 56%-95. 93%;water absorption: 42.27% - 92. 12%; bulk density:1.04g/cm3 - 1.41g/cm3; apparent density: 2. 56g/cm3 -5. 77g/cm3 ; and thermal conductivity: 0. 005 W/mK 0. 134W/mK. The results showed that they all had good insulating characteristics. Samples 1 -5 and 10 showed good level of refractoriness, while mixing ratio of 4∶1∶2 ( representing weight in grams of Kaolin, plastic clay and rice husk respectively) for sample 4 gave the optimum performance values in terms of refractoriness,thermal conductivity, modulus of rupture, shrinkage and bulk density and the effective moisture content.

  5. Influence of functional silanes on hydrophobicity of MCM-41 synthesized from rice husk

    S. Chiarakorn et al


    Full Text Available Mesoporous molecular sieve MCM-41 was synthesized from rice husk and rice husk ash, called RH-MCM-41 and RHA-MCM-41. The sol–gel mixtures were prepared with molar composition of 1.0 SiO2: 1.1 NaOH: 0.13 CTAB: 0.12 H2O. After calcination, the polarity of MCM-41 still remained on its surface due to the existence of some silanol groups. In this study, both RH-MCM-41 and RHA-MCM-41 were silylated with two different functional silanes trimethylchlorosilane (TMCS and phenyldimethylchlorosilane (PDMS in order to reduce the surface polarity. The efficiency of silylation was determined based on the amount of moisture adsorbed using thermogravimetric analysis (TGA. The structure of silylating agents and silica templates were found to be important parameters affecting the hydrophobic property of the MCM-41 surface. The post-grafting silylation with aliphatic silane can decrease the surface polarity better than that with aromatic silane, probably due to less sterric hindrance effect. Thus, the surface hydrophobicity of MCM-41 can be improved by the silylation of small molecular silane on RH-MCM-41.

  6. Production of technical silicon and silicon carbide from rice-husk

    A. Z. Issagulov


    Full Text Available In the article there are studied physical and chemical properties of silicon-carbonic raw material – rice-husk, thermophysical characteristics of the process of rice-husk pyrolysis in nonreactive and oxidizing environment; structure and phase composition of products of the rice-husk pyrolysis in interval of temperatures 150 – 850 °С and high temperature pyrolysis in interval of temperatures 900 – 1 500 °С. There are defined the silicon-carbon production conditions, which meet the requirements applicable to charging materials at production of technical silicon and silicon carbide.

  7. Effect of acetic acid on rice seeds coated with rice husk ash

    Lizandro Ciciliano Tavares; André Pich Brunes; Daniel Andrei Robe da Fonseca; Gizele Ingrid Gadotti; Lilian Madruga de Tunes; Géri Eduardo Meneghello; Antonio Carlos Souza Albuquerque Barros


    Flooded rice cultivation promotes anaerobic conditions, favoring the formation of short chain organic acids such as acetic acid, which may be toxic to the crop. The objective of this study was to evaluate the effect of acetic acid on rice seeds coated with rice husk ash. The experiment was arranged in a 2 x 5 x 5 factorial randomized design, with two cultivars (IRGA 424 and BRS Querência), five doses of coating material (0, 2, 3,4 e 5 g kg-1 seed) and five concentrations of acetic acid (0, 3,...

  8. Studies on the Effect of Rice Husk Ash as Cement Admixture * M.U ...


    ABSTRACT: Compressive strength tests were carried out on six mortar cubes with cement replaced by rice husk ... This result, therefore, indicated that RHA can be used as cement substitute ..... The loss on ignition obtained (18.25%) is higher.

  9. Removal of Zn(II) and Pb (II) ions Using Rice Husk in Food Industrial ...

    Michael Horsfall

    Removal of Zn(II) and Pb (II) ions Using Rice Husk in Food Industrial Wastewater. *ASRARI, ELHAM; TAVALLALI ... Payame Noor University (PNU), Shiraz, 711955 -1368, Iran ... need to reconsider consumption patterns and the way resources ...

  10. effects of variability in the pozzolanic properties of rice husk ash on ...


    Keywords: Compressive Strength, Concrete, Rice Husk Ash (RHA), ... When the material is mixed with lime in powdered .... that it was free from deleterious materials as required .... Properties and Drying Shrinkage”, Australian Journal of.

  11. Effect of rice husk ash on some geotechnical properties of lateritic


    The study is an investigation into the effect of rice husk ash (RHA) on some geotechnical properties of a ... Optimum Moisture Content (OMC), California Bearing Ratio (CBR) and Consistency indices. ... RHA used as overall binder system for.

  12. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    Katsuki, Hiroaki; Komarneni, Sridhar


    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO 2 and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 °C for 2-6 h by changing the SiO 2/Al 2O 3, H 2O/Na 2O and Na 2O/SiO 2 molar ratios of precursors in the two-step process. The surface area and NH 4+-cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m 2/g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m 2/g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of ˜3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously.

  13. Development of Briquette from Coir Dust and Rice Husk Blend: An Alternative Energy Source

    Md. Hamidul Islam


    Full Text Available Biomass is one of the predominant renewable energy sources and the use of biomass for the energy generation has got much attention due to its environmental friendliness. Densification of coir dust into fuel briquette can solve waste disposal problem as well as can serve as an alternative energy source. The objective of this study was to investigate the possibility of producing briquette from coir dust and rice husk blend without binder. During this study, a briquetting experiment was conducted with different coir dust and rice husk blends (i.e. coir dust and rice husk ratio of 80:20, 60:40, 50:50, 40:60, 20:80 and 0:100. Briquetting operation was performed using a die-screw press type briquetting machine. The briquettes were tested to evaluate their density, compressive strength, calorific value, burning rate and water vaporizing capacity and it was found that mixing ratio had a significant effect on the physical, mechanical and combustion properties of the coir dust-rice husk briquettes. Density, compressive strength and calorific value and water vaporizing capacity were increased with increasing mixing ratio while burning rate was decreased. Coir dust-rice husk briquettes with mixing ratio of 20:80 had higher density (1.413 g/cm3, compressive strength (218.4 N/cm2, calorific value (4879 kcal/kg, water vaporizing capacity (0.853 l/kg and low burning rate (0.783 kg/hour followed by the mixing ratio 40:60, 50:50, 60:40 and 0:100. The results indicate that coir dust and rice husk blend briquettes were found to have better overall handling characteristics over rice husk briquette. However, production of briquettes from coir dust and rice husk at mixing ratio of 50:50 was found to be more suitable for commercial application in terms of cost effectiveness.

  14. Effect of Rice Husk Ash on Cement Stabilized Laterite



    Full Text Available Laterite soil collected from Maikunkele area of Minna, classified as an A-7-6 on AASHTO classification, was stabilized with 2-8% cement by weight of the dry soil. Using British Standard Light (BSL compaction energy, the effect of Rice Husk Ash (RHA on the soil was investigated with respect to compaction characteristics, California Bearing Ratio (CBR and Unconfined Compressive Strength (UCS tests. Results obtained, indicate a general decrease in Maximum Dry Density (MDD and increase in Optimum Moisture Content (OMC, all with increase in RHA Content (2-8% at specified cement contents. There was also a tremendous improvement in the CBR and UCS with increase in the RHA content at specified cement contents to their peak values at between 4-6% RHA. The UCS values also improved with curing age. This indicates the potentials of using 4-6% RHA admixed with less cement contents for laterite soil stabilization.

  15. Effect of acetic acid on rice seeds coated with rice husk ash

    Lizandro Ciciliano Tavares


    Full Text Available Flooded rice cultivation promotes anaerobic conditions, favoring the formation of short chain organic acids such as acetic acid, which may be toxic to the crop. The objective of this study was to evaluate the effect of acetic acid on rice seeds coated with rice husk ash. The experiment was arranged in a 2 x 5 x 5 factorial randomized design, with two cultivars (IRGA 424 and BRS Querência, five doses of coating material (0, 2, 3,4 e 5 g kg-1 seed and five concentrations of acetic acid (0, 3, 6, 9 and 12 mM, with 4 replications, totaling 50 treatments. The variables first count of germination, germination, shoot and root length, dry weight of shoots and roots were recorded. The results showed that coating rice seeds with rice husk ash up to 5 g kg-1 seed does not influence the performance of rice seeds of cultivars IRGA 424 and BRS Querência when exposed to concentrations of 12 mM acetic acid. The presence of acetic acid in the substrates used for seed germination reduced the vigor and viability of seeds of cultivars IRGA 424 and BRS Querência, as well as seedling development, affecting mainly the roots of BRS Querência.

  16. Effect of grinding on chemical and physical properties of rice husk ash

    Sumrerng Rukzon; Prinya Chindaprasirt; Rattana Mahachai


    The effect of grinding on the chemical and physical properties of rice husk ash was studied.Four rice husk ashes with dif-ferent finenesses, i.e.coarse original rice husk ash (RHA0), RHAI, RHA2, and RHA3 were used for the study.Ordinary Portland cement (OPC) was partially replaced with rice husk ash at 20% by weight of binder.The water to binder ratio (W/B) of the mortar was maintained at 110%±5% with flow table test.Specific gravity, fineness, chemical properties, compressive strength, and porosity test of mortars were determined.The differences in chemical composition of the rice husk ashes with different finenesses from the same batch are small.The use of RHA3 produces the mortars with good strength and low porosity.The strength of the mortar im-proves with partial replacement of RHA3 in comparison with normal coarse rice husk ash.The use of RHA3 results in a strong anddense mortar, which is due to the better dispersion and filling effect, as well as an increase in the pozzolanic reaction.

  17. Bioethanol production from steam-exploded rice husk by recombinant Escherichia coli KO11.

    Tabata, Takamitsu; Yoshiba, Yusuke; Takashina, Tomonori; Hieda, Kazuo; Shimizu, Norio


    Rice husk is one of the most abundant types of lignocellulosic biomass. Because of its significant amount of sugars, such as cellulose and hemicellulose, it can be used for the production of biofuels such as bioethanol. However, the complex structure of lignocellulosic biomass, consisting of cellulose, hemicellulose and lignin, is resistant to degradation, which limits biomass utilization for ethanol production. The protection of cellulose by lignin contributes to the recalcitrance of lignocelluloses to hydrolysis. Therefore, we conducted steam-explosion treatment as pretreatment of rice husk. However, recombinant Escherichia coli KO11 did not ferment the reducing sugar solution obtained by enzymatic saccharification of steam-exploded rice husk. When the steam-exploded rice husk was washed with hot water to remove inhibitory substances and M9 medium (without glucose) was used as a fermentation medium, E. coli KO11 completely fermented the reducing sugar solution obtained by enzymatic saccharification of hot water washing-treated steam-exploded rice husk to ethanol. We report here the efficient production of bioethanol using steam-exploded rice husk.

  18. Use or rice husk ash an addition in mortar

    Sánchez de Rojas, M. Isabel


    Full Text Available With the aid of a 400-litre capacity pilot furnace, in which 40 Kg of rice husk is submitted to controlled combustion, an ash (RHA is obtained for use as an addition, the physicochemical properties of which form the focal point of this work. Results will also be presented for the combustion power of the husk ≃ 4000 kcal/kg, being greater than half the value for normal bituminous coals. Conglomerates have been obtained by mixing RHA with different proportions of lime and portland cement, and their properties are studied with regard to both mortars and concretes. The ultimate aim of the work is to demonstrate how rice husk (world production of which is estimated at 500.106 m3 per annum may be feasibly applied as an addition, without forgetting its excellent properties as a fuel, which makes it particularly suitable for developing countries with a shortage of cement and energy resources.

    Mediante la utilización de un horno-piloto de unos 400 litros de capacidad, en el que se realiza la combustión controlada de unos 40 kg de cáscara de arroz, se consigue una ceniza (RHA, sobre cuyas propiedades físico-químicas se centra el trabajo, para su empleo como adición. Se presentan igualmente resultados sobre el poder de combustión de la cascara ≃ 4.000 kcal/kg, superior a la mitad del valor de los carbones bituminosos normales. Mediante mezclas de RHA con distintas proporciones de cal o de cemento portland, se han conseguido conglomerantes cuyas propiedades se estudian, tanto sobre morteros, como sobre hormigones. El objetivo último del trabajo es mostrar la factible aplicabilidad de la cascara de arroz (cuya "producción" mundial se estima en 500.106 m3 anuales como adición, sin olvidar sus excelentes cualidades como combustible lo que hace especialmente idónea en países en vías de desarrollo, deficitarios en cemento y recursos energéticos.

  19. Adsorption Studies of Phenol Using Thermally and Chemically Modified Rice Husk as Adsorbents

    *M. M. Yousaf


    Full Text Available Most of the Phenols are hazardous substances and some are supposed to have carcinogenic activity. Thus it is necessary to remove Phenolics and other aromatics from the aqueous ecosystem. Traditional processes for the removal of Phenolics compounds are extraction, adsorption on granulated activated carbon, steam distillation, chemical and bacterial techniques. Literature survey show a number of methods like oxidation, ion exchange, reverse osmosis, electrochemical oxidation and adsorption. Phenol removal by process like, adsorption is the best method of choice as it can remove most of phenols in simple and easy way. In recent past; agricultural by-products such as, maize cob, date stone, apricot Stones, rice bran, and bagass pith have been extensively studied and used as adsorbents for the adsorption of hazardous substances from wastewater. In the present study we tried modified rice husks as potential adsorbents for the removal of Phenol from aqueous system. Batch mode studies were carried out. Isotherm data was generated and fitted in Freundlich and Langmuir equation to explain the phenomenon of adsorption. The adsorption capacities based on Langmuir model (Qm of the 3 adsorbents were found to be 0.81 for raw husk (RH, 0.395 for the Grafted (G and 2.306 mg/g for the Charred (C. The R2 values were 0.92 for raw husk, 0.97 for grafted and 0.91 for charred husk. Based on Freundlich model the adsorption capacities (K were 2.94, 2.29 and 1.25mg/g for Raw husk, grafted husk and charred husk. The R2 values were found to be 0.72, 0.95 and 0.83 for the raw husk, grafted husk and charred husk respectively. Our result showed that modified rice husks could be used as potential adsorbents for Phenol removal from aqueous system.

  20. Use of Rice Husk Ash as Partial Replacement with Cement In Concrete- A Review

    Sourav Ghosal,


    Full Text Available Rapid increase in construction activities has resulted in shortage of conventional construction materials.In the present scenario, the high cost of conventional building materials is a major factor affecting housing delivery in the world.This has necessitated research into alternative materials of construction.The effective housing techniques deal with reduction in cost of construction as well as providing strength to buildings.Mainly gravel,sand and cement are used in the preparation of conventional concrete.While the use of agricultural by-product i.e. rice husk as a partial replacement with the conventional fine aggregates is expected to serve the purpose of encouraging housing developers in building construction.Rice husk is produced in about 100 million tons per annum in India. Twenty kg of rice husk are obtained from 100 kg of rice.It contains organic substances and 20% inorganic material.Ash from rice is obtained as a result of combustion of rice husk at suitable temperature. Proper utilization of it aims to save the environment,encourages the Government to find solutions regarding disposal to land fills of waste materials,and provides new knowledge to the contractors and developers on how to improve the construction industry by using rice husk, to sustain good product performance and to meet recycling goals.The rice husk ash concrete aims to prepare light weight structural concrete which may reduce considerably the self load of structures and permits large precast units to be handled.The main objective is therefore to encourage the use of these ‘seemingly’ waste products as construction materials in low cost housing.The various basic properties of rice husk concrete are reviewed in this paper.

  1. The influence of Rice Husk Fiber on The Properties of Epoxidized Natural Rubber/Rice Husk Compounds

    Dahham Omar S.


    Full Text Available In this work, curing characteristics, tensile and physical properties of epoxidized natural rubber/rice husk (ENR-50/RH compounds were investigated. Different RH loading (10, 20, 30, 40 and 50 Phr and size (fine size at 100-300 μm and coarse size at 5-10 mm were prepared and used. Results indicated that the scorch time (t2 and cure time (t90 became shorter with increasing RH content. In contrast, minimum torque (ML and maximum torque (MH increased with increasing RH content in the rubber compounds. Hardness and crosslink density showed improvement with increasing RH content. Tensile strength (Ts and elongation at break (Eb decreased slightly as RH content increased. However, the fine size of RH recorded better overall properties compared to the RH coarse size at same loading the rubber compound.

  2. Cellulose fibers extracted from rice and oat husks and their application in hydrogel.

    Oliveira, Jean Paulo de; Bruni, Graziella Pinheiro; Lima, Karina Oliveira; Halal, Shanise Lisie Mello El; Rosa, Gabriela Silveira da; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa


    The commercial cellulose fibers and cellulose fibers extracted from rice and oat husks were analyzed by chemical composition, morphology, functional groups, crystallinity and thermal properties. The cellulose fibers from rice and oat husks were used to produce hydrogels with poly (vinyl alcohol). The fibers presented different structural, crystallinity, and thermal properties, depending on the cellulose source. The hydrogel from rice cellulose fibers had a network structure with a similar agglomeration sponge, with more homogeneous pores compared to the hydrogel from oat cellulose fibers. The hydrogels prepared from the cellulose extracted from rice and oat husks showed water absorption capacity of 141.6-392.1% and high opacity. The highest water absorption capacity and maximum stress the compression were presented by rice cellulose hydrogel at 25°C. These results show that the use of agro-industrial residues is promising for the biomaterial field, especially in the preparation of hydrogels.

  3. Energy potential from rice husk through direct combustion and fast pyrolysis: A review.

    Quispe, Isabel; Navia, Rodrigo; Kahhat, Ramzy


    Rapid population growth and consumption of goods and services imply that demand for energy and resources increases continuously. Energy consumption linked to non-renewable resources contributes to greenhouse gas emissions and enhances resource depletion. In this context, the use of agricultural solid residues such as rice husk, coffee husk, wheat straw, sugar cane bagasse, among others, has been widely studied as an alternative energy source in order to decrease the use of fossil fuels. However, rice husk is among those agricultural residues that are least used to obtain energy in developing countries. Approximately 134 million tonnes of rice husk are produced annually in the world, of which over 90% are burned in open air or discharged into rivers and oceans in order to dispose of them. This review examines the energetic potential of agricultural residues, focused on rice husk. The review describes direct combustion and fast pyrolysis technologies to transform rice husk into energy considering its physical and chemical properties. In addition, a review of existing studies analyzing these technologies from an environmental life cycle thinking perspective, contributing to their sustainable use, is performed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Elucidation of the effect of ionic liquid pretreatment on rice husk via structural analyses

    Ang Teck


    Full Text Available Abstract Background In the present study, three ionic liquids, namely 1-butyl-3-methylimidazolium chloride ([BMIM]Cl, 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc, and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM]DEP, were used to partially dissolve rice husk, after which the cellulose were regenerated by the addition of water. The aim of the investigation is to examine the implications of the ionic liquid pretreatments on rice husk composition and structure. Results From the attenuated total reflectance Fourier transform-infrared (ATR FT-IR spectroscopy, X-ray diffraction (XRD and scanning electron microscopy (SEM results, the regenerated cellulose were more amorphous, less crystalline, and possessed higher structural disruption compared with untreated rice husk. The major component of regenerated cellulose from [BMIM]Cl and [EMIM]DEP pretreatments was cellulose-rich material, while cellulose regenerated from [EMIM]OAc was a matrix of cellulose and lignin. Cellulose regenerated from ionic pretreatments could be saccharified via enzymatic hydrolysis, and resulted in relatively high reducing sugars yields, whereas enzymatic hydrolysis of untreated rice husk did not yield reducing sugars. Rice husk residues generated from the ionic liquid pretreatments had similar chemical composition and amorphousity to that of untreated rice husk, but with varying extent of surface disruption and swelling. Conclusions The structural architecture of the regenerated cellulose and rice husk residues showed that they could be used for subsequent fermentation or derivation of cellulosic compounds. Therefore, ionic liquid pretreatment is an alternative in the pretreatment of lignocellulosic biomass in addition to the conventional chemical pretreatments.

  5. Development of carbon dioxide adsorbent from rice husk char

    Abang, S.; Janaun, J.; Anisuzzaman, S. M.; Ikhwan, F. S.


    This study was mainly concerned about the development of carbon dioxide (CO2) adsorbent from rice husk (RH). Several chemical treatments were used to produce activated rice husk char (RHAC) from RH. Initially the RH was refluxed with 3M of sodium hydroxide (NaOH) solution, activation followed by using 0.5M of zinc chloride (ZnCl2) solution and finally acidic treatment by using 0.1M of hydrochloric acid (HCl). Then, the RHAC was functionalized by using 3-chloropropylamine hydrochloride (3-CPA) and noted as RHN. RHN samples were characterized with scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), fourier transform infrared spectroscopy (FTIR). Based on the SEM, the RHN sample had a large pore diameter compared to RH sample after being treated. Based on MIP data, the average pore diameter between RH and RHAC samples were increased significantly from 0.928 microns to 1.017 microns. The RHN sample also had higher total porosity (%) compared to RHAC and RH (58.45%, 47.82% and 45.57% respectively). The total specific surface area of the sample was much increasing from RHO to RHAC (29.17 m2/g and 62.94 m2/g respectively) and slightly being decreasing from RHAC to RHN (58.88 m2/g). FTIR result showed the present of weak band at 1587 cm-1 which demonstrating of the amine group present on the sample. The CO2 capture result showed that the decreasing of operating temperature can increase the breakthrough time of CO2 capture. On the contrary decreasing of CO2 gas flow rate can increase the breakthrough time of CO2 capture. The highest total amount of CO2 adsorbed was 25338.57 mg of CO2/g of RHN sample by using 100 mL/min of gas flow rate at 30oC. Based on adsorption isotherm analysis, the Freundlich isotherm was the best isotherm to describe the CO2 adsorption on the sample.

  6. Studies on the properties of rice-husk-filled-PP composites: effect of maleated PP

    Simone Maria Leal Rosa


    Full Text Available Rice husk is a by-product of rice milling process that usually finds inadequate final disposal (burning, land filling. Thermoplastics composites filled with rice husk flour are materials that offer an alternative for using this agricultural resource viewing the production of low dense materials with some specific properties. In this work composites of polypropylene (PP and rice husk flour (RHF were prepared by melt extrusion. Maleic anhydride-modified PP (MAPP was added as a coupling agent. It was verified that tensile strength decreased with filler loading. The presence of MAPP improved this property showing a strong dependence on the MAPP/RHF ratio (MAPP/RHF = 0.03 produced the best results. The density of the composites slightly increased with filler and coupling agent in comparison to pure PP. The presence of MAPP diminished more than 20% water uptake in highly-loaded composites.

  7. Performance Evaluation of Steel Fibres in Rice Husk Ash Substituted Concretes

    A. Sivakumar


    Full Text Available The potential use of supplementary cementitious materials in plain cement concrete for improving concrete properties has been a growing concern in recent years. In addition, the effective strengthening of the matrix by fibre reinforcements to avoid brittle failure is another requirement for plain concrete. This provided the motivation for exploring the benefits of rice husk ash (RHA as a cement replacement material and the addition of steel fibres for reducing brittleness in concrete. The rice husk ash used in this study was the residue of burnt raw rice husk sintered in a muffle furnace at 800 °C. The fine particle size of the rice husk ash provided an early pozzolanic reaction upon cement hydration and thus resulted in high cementing efficiency. This paper reports a systematic evaluation of the mechanical properties of rice husk ash substituted concrete mixtures containing RHA as a partial cement substitute at replacement levels of 10% and 20% by weight of cement, with different dosages of steel fibres. Our experimental results demonstrated that 10% RHA substitution led to improved compressive properties compared to plain concrete. The highest increase of split tensile and flexural strength was reported in the case of RHA substituted concrete with steel fibre added.

  8. Durability of Concrete Using Rice Husk Ash as Cement Substitution Exposed To Acid Rain

    I. A. Ahmad


    Full Text Available The acidity of rainfall in major areas of Indonesia is under neutral pH. Average pH of rainfall is between 3 and 5. Free lime within concrete will react with acid and cause a decrease in the strength of concrete. A means to anticipate the damage is to reduce the content of free lime within concrete. Silicon oxide contained in rice husk ash can react with free lime to form a new compound that is harder and denser. It became the basis for the use of rice husk ash in concrete mixtures. The mixtures were prepared by replacing 5% and 10% of cement with rice husk ash and the results were compared with a reference mix with 100% cement. This paper presents the results of an experimental investigation on the mechanical characteristics of concrete specimens as durability parameters. Then to evaluate the mechanical characteristics, microstructure test was conducted. The lower the mechanical properties of the concrete, the higher the level of gypsum contained within concrete. The percentage of 5% rice husk ash of the cement weight has a lower compressive strength decrease than the 10% rice husk ash. In addition, the proposed durability model is a model of polynomial equation with two variables.

  9. Characterization of hydrochars produced by hydrothermal carbonization of rice husk

    D. Kalderis


    Full Text Available Biochar is the carbon-rich product obtained when biomass, such as wood, manure or leaves, is heated in a closed container with little or no available air. In more technical terms, biochar is produced by so-called thermal decomposition of organic material under limited supply of oxygen (O2, and at relatively low temperatures (<700 °C. Hydrochar differentiates from biochar because it is produced in an aqueous environment, at lower temperatures and longer retention times. This work describes the production of hydrochar from rice husks using a simple, safe and environmentally-friendly experimental set-up, previously used for degradation of various wastewaters. Hydrochars were obtained at 200°C and 300°C and at residence times ranging from 2 to 16 h. All samples were then characterized in terms of yield, surface area, pH, conductivity and elemental analysis and two of them were selected for further testing with respect to heating values and heavy metal content.

  10. Catalytic pyrolysis of waste rice husk over mesoporous materials

    Jeon, Mi-Jin; Kim, Seung-Soo; Jeon, Jong-Ki; Park, Sung Hoon; Kim, Ji Man; Sohn, Jung Min; Lee, See-Hoon; Park, Young-Kwon


    Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH3 temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brönsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics.

  11. Properties of Rice Husk Ash Stabilized Laterite Roof Tiles

    Momoh Omuya RAHEEM


    Full Text Available This paper presents the results of work on the possibility of using of Rice Husk Ash (RHA in the production of clay roof tiles. The pozzolana content of the ash was determined using X-Ray Fluorescence (XRF to confirm the key elements of RHA as a good pozzolanic material. The tiles were produced by moulding clay-RHA blends of various proportions of RHA used in wooden moulds. The percentages by weight of RHA added to various mixes were 0, 5, 10, 15, 20, 25 and 30% RHA and the tiles were fired at 900°C, 1000°C and 1100°C in an electric furnace. The water absorption, density, permeability and Transverse Breaking Stress (TBS of the roof tile produced were tested using manual TBS testing apparatus and weighing balances. The relative trends of the properties tested were dependent on pozzolanic property of RHA and since the sum of the active pozzolanas - SiO2, Al2O3 and Fe2O3 present in the ash is 86.01% and meets 70% minimum recommend by ASTM C618-92a for Class F pozzolana. Most optimal results were obtained at 15% RHA and 900°C temperature for water absorption, density, permeability and Transverse Breaking Stress (TBS.

  12. Radon resistant potential of concrete manufactured using Ordinary Portland Cement blended with rice husk ash

    Chauhan, R. P.; Kumar, Amit


    The emission of radon from building materials and soil depends upon the radium content, porosity, moisture content and radon diffusion length of materials. Several techniques have been used to reduce the radon emission from the soil using different flooring materials. But the effectiveness of radon shielding depends upon the diffusion of radon through these materials. The present study proposes a method for producing a radon resistant material for decreasing radon diffusion through it. The method involves rice husk ash (RHA) in addition to cement for the preparation of concrete used for flooring and walls. The radon diffusion, exhalation and mechanical property of concrete prepared by rice husk ash blended cement were studied. The addition of RHA caused the reduction in radon diffusion coefficient, exhalation rates, porosity and enhanced the compressive strength of concrete. The bulk radon diffusion coefficient of cementitious concrete was reduced upto 69% by addition of rice husk ash as compare to that of control concrete.

  13. Recycled High-Density Polyethylene and Rice Husk as a Wetted Pad in Evaporative Cooling System

    Nitipong Soponpongpipat


    Full Text Available Problem statement: The low cost and easy-to-find materials, for being used as wetted pad of evaporative cooling system, are necessary for agriculture. This study, thus, studied the evaporative cooling efficiency and pressure drop of recycled High-Density Polyethylene (HDPE and rice husk as a wetted pad in evaporative cooling system. Approach: The study was done by establishing the tested wetted pad with 25.4 and 50.8 mm of thickness. The velocity air flow through wetted pad was controlled at 1, 2 and 3 m sec−1 respectively. In addition, the dry bulb and wet bulb temperatures of inlet air were controlled at 30.1 ± 1.0°C and 23.2 ± 1.1°C, respectively. The commercial wetted pad was also tested in order to compare results with rice husk and recycled HDPE. Results: It was found that rice husk wetted pad gave the average saturation efficiency of 55.9 %, while HDPE gave the average saturation efficiency of 29.1%. However, the pressure drop across wetted pad of rice husk and recycled HDPE was significantly higher than that of commercial wetted pad. For the effect of air velocity on saturation efficiency and pressure drop, it was found that higher air velocity decreased saturation efficiency and increased pressure drop across wetted pad. Conclusion: Finally, the rice husk has a potential as wetted pad material. However, further study about optimum point between operation cost and materials cost of using rice husk wetted pad is needed.

  14. Properties of Rice Husk Ash (RHA and MIRHA Mortars

    Narayanan Sambu Potty


    Full Text Available Rice husk Ash (produced by traditional burning called RHA and by using microwave incinerator called MIRHA has shown promise as a cement replacement material. This study investigated the properties of RHA and MIRHA mortar used for brick manufacture at binder sand proportions of 1:3 and 1:4. RHA and MIRHA were intermediate in particle size to cement and sand particles. Percentages of replacement were 5, 10, 15, 20, 25 and 30%, respectively. Strength at w/c ratios (0.5, 0.55, 0.6 and 0.65, respectively was investigated to identify optimum w/c ratios as well as optimum percent replacement of RHA and MIRHA. Variations of IRS, density and water absorption were investigated. Generally 1:3 RHA and 1:3 MIRHA mortars strength showed decreasing trend with increasing percentage replacement with RHA and MIRHA. Whereas 1:4 RHA and 1:4 MIRHA mortars showed increase in strength at 5% replacement and decrease thereafter. IRS values for RHA mortars are generally within limits (0.25-1.5 kg/m2.min recommended. Water absorption values of RHA mortars are generally higher than control mortar. IRS values for MIRHA mortars with w/c 0.5 and 0.55 ranged between 1.4-2.0 kg/m2 .min; indicating the need for wetting the bricks before use. IRS values for 1:3 MIRHA mortars with w/c 0.6 and 0.65 were below 1.0 kg/m2.min indicating low suction values. For 1:4 MIRHA mortars, IRS values were very low in all cases. Water absorption values of MIRHA mortars are generally higher than the control mortar. MIRHA mortars with w/c 0.6 and 0.65 showed low percentages of water absorption.

  15. Use of heterogeneous CaO and SnO{sub 2} catalysts supported on rice husk ash to produce biodiesel; Emprego de catalisadores heterogeneos de CaO e SnO{sub 2} suportados em cinza de casca de arroz na obtencao de biodiesel

    Soares, Ana Brigida [Instituto Federal do Espirito Santo, Vitoria, ES (Brazil); Silva, Paulo Roberto Nagipe da; Stumbo, Alexandre Moura, E-mail: [Laboratorio de Ciencias Quimicas, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ (Brazil); Freitas, Jair C.C. [Departamento de Fisica, Centro de Ciencias Exatas, Universidade Federal do Espirito Santo, Vitoria, ES (Brazil)


    Silica obtained from rice husk after acid leaching and calcination was compared to commercial silica as a catalyst support. CaO and SnO{sub 2} catalysts were prepared by impregnation and tested in the transesterification of soybean oil and the esterification of oleic acid. CaO catalysts showed basic character and were the most active for transesterification, whereas SnO{sub 2} catalysts were acid and the most effective for esterification. In both cases the performances of the catalysts prepared with rice husk ash and commercial silica were similar. These results demonstrate that rice husk is a cost-effective and environmentally-friendly source of silica that can be used as a catalyst support. (author)

  16. Malaysian Rice Husk Ash – Improving the Durability and Corrosion Resistance of Concrete: Pre-review

    Hamidi Abdulaziz


    construction materials is the outcome of the fast polluting environment. Supplementary cementitious materials prove to be effective to meet most of the requirements of durable concrete. Rice husk ash is found to be greater to other supplementary materials like silica fume and fly ash. Due to its high pozzolanic activity, both strength and durability of concrete are enriched. Addition of rice husk ash to Portland cement not only improves the early strength of concrete, but also forms a calcium silicate hydrate gel around the cement particles which is highly dense and less porous. This may increase the strength of concrete against cracking. Previously, investigation on the corrosion performance of rice husk ash blended concrete is very limited. Further researches are ongoing or have started recently by the authors to study the performance of RHA and corrosion of concrete mixes. Various tests were carried out to evaluate durability of concrete made with 10, 20, 30 and 40% replacements of RHA by weight of cement. Nevertheless, the results of compressive strength, absorption test and chloride penetration from previous investigation were presents in this study.

  17. Engineering Properties of an Expansive soil Stabilized with Rice husk ash and Lime sludge

    Akshaya Kumar Sabat


    Full Text Available Compaction properties, California bearing ratio, shear strength parameters, compression index, swelling pressure and durability of an expansive soil stabilized with rice husk ash and lime sludge have been discussed in this paper. The effects of 7 and 28 days of curing on these properties except the compaction properties have also been discussed.

  18. rice-husk ash-carbide-waste stabilization of reclaimed asphalt ...



    Jul 3, 2016 ... utilization of these wastes for beneficial engineering purposes has prompt an ... reported that rice-husk ash have thermal conductivity of 0.065 Wm-1k-1. ..... Related to its Industrial Application”, Journal of. Material Science, Vol ...

  19. Prospects of using whole rice husk for the production of dense and ...


    can be an excellent material for brick production thereby presenting a good alternative to OPC. Key words: .... ceramics from cement kiln dust and rice husk ash through ... brick properties. .... Nevertheless though many uses had ..... Solutions to Dearth of Affordable Housing,” Vanguard Mobile Edition, ... Concrete Structures.

  20. Pantoea ananatis as a Cause of Corneal Infiltrate after Rice Husk Injury

    Manoharan, Geetha; Jeganathan, Lakshmi Priya; DSilva, Sean Socrates; Prajna, N. Venkatesh


    We report a case of an agricultural worker presenting with corneal infiltrate following ocular injury with a rice husk. On examination, a superficial corneal foreign body was removed and sent for culture, which grew Pantoea ananatis. This is, to our knowledge, the first clinical case report of Pantoea ananatis causing corneal infiltrate. PMID:22461671

  1. Synthesis of SiC from rice husk in a plasma reactor

    S K Singh; B C Mohanty; S Basu


    A new route for production of SiC from rice husk is reported by employing thermal plasma technique. The formation of -SiC is observed in a short time of 5 min. The samples are characterized by XRD and SEM.

  2. Sorption of Pb2+ from Aqueous Solution unto Modified Rice Husk: Isotherms Studies

    A. O. Dada


    Full Text Available Investigation of the sorption potential of rice husk, an agricultural waste, as an adsorbent was carried out. The rice husk was modified with orthophosphoric acid and was used for adsorption of lead (II ions (Pb2+ from aqueous solution. Physicochemical properties of the modified rice husk were determined. Equilibrium sorption data were confirmed with Langmuir, Freundlich and Temkin adsorption isotherms. On the basis of adsorption isotherm graphs, R2 values were determined to be 0.995, 0.916, and 0.797 for Langmuir, Temkin, and Freundlich isotherms, respectively, indicating that the data fitted well into the adsorption isotherms, but Langmuir isotherm is a better model. The maximum monolayer coverage from Langmuir studies, Qmax=138.89 mg/g, Langmuir isotherm constant, KL=0.699 L/mg, and the separation factor, RL=1.41×10−2 at 100 mg/L of lead(II ions indicating that the sorption process, was favourable. The suitability of modified rice husk as an adsorbent for the removal of lead ions from aqueous solution and its potential for pollution control is established.

  3. Synthesis of silicon carbide from rice husk in a packed bed arc reactor

    Mishra, P.K.; Nayak, B.B.; Mohanty, B. [Regional Research Lab., Bhubaneswar (India)


    Silicon carbide in the form of powder was prepared from boiler burnt rice husk in a new type of packed bed arc reactor where the raw materials were processed in briquette form. X-ray diffraction analysis identified the presence of both {beta} and {alpha} SiC. Microstructural characterization revealed the presence of triangular, truncated triangular, and hexagonal crystallites, along with platelets.

  4. Gas chromatographic-mass spectrometric analysis of tar compounds formed during pyrolysis of rice husks

    Haanappel, V.A.C.; Stevens, T.W.; Hovestad, A.; Skolnik, V.; Visser, R.


    Pyrolysis of agricultural waste to produce fuel gas involves formation of tars as noxious by-products. In this paper the qualitative analysis of tars formed during pyrolysis of rice husks is presented, based on identification by gas chromatography—mass spectrometry and interpolation of retention tim

  5. A Study of the Anechoic Performance of Rice Husk-Based, Geometrically Tapered, Hollow Absorbers

    Muhammad Nadeem Iqbal


    Full Text Available Although solid, geometrically tapered microwave absorbers are preferred due to their better performance, they are bulky and must have a thickness on the order of λ or more. The goal of this study was to design lightweight absorbers that can reduce the electromagnetic reflections to less than −10 dB. We used a very simple approach; two waste materials, that is, rice husks and tire dust in powder form, were used to fabricate two independent samples. We measured and used their dielectric properties to determine and compare the propagation constants and quarter-wave thickness. The quarter-wave thickness for the tire dust was 3 mm less than that of the rice husk material, but we preferred the rice-husk material. This preference was based on the fact that our goal was to achieve minimum backward reflections, and the rice-husk material, with its low dielectric constant, high loss factor, large attenuation per unit length, and ease of fabrication, provided a better opportunity to achieve that goal. The performance of the absorbers was found to be better (lower than −20 dB, and comparison of the results proved that the hollow design with 58% less weight was a good alternative to the use of solid absorbers.

  6. Study on properties of rice husk ash and its use as cement replacement material

    Ghassan Abood Habeeb


    Full Text Available This paper investigates the properties of rice husk ash (RHA produced by using a ferro-cement furnace. The effect of grinding on the particle size and the surface area was first investigated, then the XRD analysis was conducted to verify the presence of amorphous silica in the ash. Furthermore, the effect of RHA average particle size and percentage on concrete workability, fresh density, superplasticizer (SP content and the compressive strength were also investigated. Although grinding RHA would reduce its average particle size (APS, it was not the main factor controlling the surface area and it is thus resulted from RHA's multilayered, angular and microporous surface. Incorporation of RHA in concrete increased water demand. RHA concrete gave excellent improvement in strength for 10% replacement (30.8% increment compared to the control mix, and up to 20% of cement could be valuably replaced with RHA without adversely affecting the strength. Increasing RHA fineness enhanced the strength of blended concrete compared to coarser RHA and control OPC mixtures.

  7. Studies on Concrete Characteristic Strength Using Fly Ash And Rice Husk Ash

    Khusbu Rajhans


    Full Text Available Through out the world, the most widely used construction material is concrete, commonly made by mixing Portland cement with sand, crushed rock, and water. As concrete is being widely used for the construction of most of the buildings, bridges etc, it has been labelled as the backbone to the infrastructure development of a nation. Currently our country is doing major work to improve and develop its infrastructure by constructing industrial and commercial projects and National Highways which creats major economic problem. At present about 120 million ton of cement is being produced in India every year. That much amount of cement is expected to reach close to 470 million ton by 2017[3].Though the production of cement is at comfortable level to meet, the rapidly increasing cost of production of cement is a matter of concern. Hence, currently the entire construction industry is in search of suitable and effective the waste product that would considerably minimize the use of cement and ultimately reduce the construction cost. Few of such products have already been identified like Rice Husk Ash (RHA, Fly Ash(FA, Silica Fume etc. Amongst them RHA is known to have good prospects in minimizing the usage of cement.

  8. Synthesis of silicon carbide from rice husk in a dc arc plasma reactor

    Nayak, B.B.; Mohanty, B.C.; Singh, S.K. [Regional Research Lab., Bhubaneswar (India)


    SiC particles have been synthesized in the {alpha}-phase from a mixture of boiler-burnt rice husk and graphite powder in a dc extended arc plasma reactor on a 200--250 g scale. A SiC yield as high as 72% was achieved at a 3.03:1 carbon-to-silica ratio. 21R polytypism, which is rare to grow, was observed in the SiC. About 90% of the SiC particles produced were found to lie under 163 {micro}m, 50% under 90 {micro}m, and 10% under 28 {micro}m size. Very fine particles under 10 {micro}m size occurred to the extent of 3%. XRD and SEM characterizations were carried out to study the phase and morphology of the particles. Heterogeneous gas-phase reactions seem to be responsible for intermediate-size SiC particle growth in the multitemperature zone dc extended arc plasma reactor.

  9. Foliar application of two silica sols reduced cadmium accumulation in rice grains.

    Liu, Chuanping; Li, Fangbai; Luo, Chunling; Liu, Xinming; Wang, Shihua; Liu, Tongxu; Li, Xiangdong


    In the present study, pot experiments were conducted to investigate the effects of foliar application of two silica (Si) sols on the alleviation of cadmium (Cd) toxicity in contaminated soil to rice. Results showed that the foliar application of Si sols significantly increased the dry weight of grains (without husk) and shoots in rice grown in Cd contaminated soil, whereas the Cd concentration in the grains and shoots decreased obviously. The total accumulation of Cd in rice grains also decreased with the application of both of the Si sols, but no significant effect was found on the Cd accumulation in the shoots. For the optimal effect, Si-sol-B should be foliar applied at the tillering-stage during rice growth. The mechanism of Si foliar application to alleviate the toxicity and accumulation of Cd in grains of rice may be related to the probable Cd sequestration in the shoot cell walls.

  10. Synthesis of A type zeolite from rice husk ash; Momigarabai kara no A gata zeolite no gosei

    Inoue, K. [Kyushu National Industrial Research Institute, Saga (Japan); Hara, N. [Kagoshima Prefectural Industrial Technology Center, Kagoshima (Japan)


    Attempts have been made on synthesizing A-type zeolite from rice husk ash made from burning under different conditions. The rice husk ash (comprising SiO2 at 90 and odd percent) was obtained by heating the rice husk to remove volatile constituents, burning at 350{degree}C to reduce carbon content, and further burning at 400 to 900{degree}C. Soda aluminate and caustic soda were used as additional materials for zeolite. Zeolite was synthesized by so mixing the raw materials that predetermined composition is achieved, adding seed crystals, and heating at 90{degree}C. The result may be summarized as follows: raising the burning temperature reduces the carbon content and increases whiteness of the rice husk ash; dissolution velocity of rice husk ash into NaOH aqueous solution was measured to evaluate the reactivity of the ash (the higher the more preferable); raised burning temperature causes transfer from amorphous state to crystalline state, reducing the dissolution velocity; the lower the burning temperature, the higher the A-type zeolite production rate becomes; whiteness in zeolite is insufficient; preparing water glass from rice husk ash and synthesizing zeolite therefrom achieves high whiteness and high production rate. 6 refs., 4 figs., 2 tabs.

  11. Studies in an atmospheric bubbling fluidized-bed combustor of 10 MW power plant based on rice husk

    Singh, Ravi Inder [Department of Mechanical Engineering, Guru Nanak Dev Engineering College, Ludhiana, Punjab 141 006 (India); Mohapatra, S.K. [Department of Mechanical Engineering, Thapar University, Patiala, Punjab (India); Gangacharyulu, D. [Department of Chemical Engineering, Thapar University, Patiala, Punjab (India)


    In this paper an experience, environmental assessment, a model for exit gas composition, agglomeration problem and a model for solid population balance of 10 MW power plant at Jalkheri, Distt. Fatehgarh Sahib, Punjab, India based on rice husk has been discussed. Three phase multistage mathematical model for exit gas composition of rice husk in fluidized bed has been derived. The model is based on three-phase theory of fluidization and material balance for shrinking rice husk particles and it is similar to model developed by Kunii and Levenspiel. The burning of rice husk is assumed to take place according to single film theory. The model has been used to predict the exit gas composition particularly O{sub 2}, CO{sub 2} and N{sub 2}. The agglomeration problem of above plant which is main reason for defluidization of bed has also been discussed. SEM of ash agglomerates has been done. Ash samples taken from the above 10 MW power plant at Jalkheri has been quantitatively analyzed. Finally solid population model has been formed to calculate bed carbon load and carbon utilization efficiency. Above two models are experimentally correlated with the data collected from the above 10 MW power plant at Jalkheri, Distt. Fatehgarh Sahib, Punjab, India which uses rice husk as a fuel input (at the time of study). All the results from the model for rice husk are coming with in permissible limits. (author)

  12. Effects of water washing and torrefaction on the pyrolysis behavior and kinetics of rice husk through TGA and Py-GC/MS.

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan


    The effects of water washing and torrefaction on the pyrolysis behavior and kinetics of rice husk were investigated through TGA and Py-GC/MS in this study. Two iso-conversional methods, i.e. Starink and FWO methods were applied for determination of the activation energy of original and pretreated rice husk samples at three different heating rates. It was found that activation energy of water washed rice husk was lower than that of original rice husk. Whereas, the activation energy increased with the increase of torrefaction temperature. The result of Py-GC/MS analysis indicated that both water washing and torrefaction pretreatments decreased the contents of acids, ketones, aldehydes and furans, while significantly increased the contents of sugars, especially levoglucosan. The relative content of released levoglucosan from pyrolysis of rice husk sample with combined water washing and 280°C torrefaction pretreatment is almost 9 times of that from original rice husk, which is about 3%.

  13. Rice Husk Ash to Stabilize Heavy Metals Contained in Municipal Solid Waste Incineration Fly Ash: First Results by Applying New Pre-treatment Technology

    Laura Benassi


    Full Text Available A new technology was recently developed for municipal solid waste incineration (MSWI fly ash stabilization, based on the employment of all waste and byproduct materials. In particular, the proposed method is based on the use of amorphous silica contained in rice husk ash (RHA, an agricultural byproduct material (COSMOS-RICE project. The obtained final inert can be applied in several applications to produce “green composites”. In this work, for the first time, a process for pre-treatment of rice husk, before its use in the stabilization of heavy metals, based on the employment of Instant Pressure Drop technology (DIC was tested. The aim of this work is to verify the influence of the pre-treatment on the efficiency on heavy metals stabilization in the COSMOS-RICE technology. DIC technique is based on a thermomechanical effect induced by an abrupt transition from high steam pressure to a vacuum, to produce changes in the material. Two different DIC pre-treatments were selected and thermal annealing at different temperatures were performed on rice husk. The resulting RHAs were employed to obtain COSMOS-RICE samples, and the stabilization procedure was tested on the MSWI fly ash. In the frame of this work, some thermal treatments were also realized in O2-limiting conditions, to test the effect of charcoal obtained from RHA on the stabilization procedure. The results of this work show that the application of DIC technology into existing treatment cycles of some waste materials should be investigated in more details to offer the possibility to stabilize and reuse waste.

  14. Adsorption of Safranin-T from wastewater using waste materials- activated carbon and activated rice husks.

    Gupta, Vinod K; Mittal, Alok; Jain, Rajeev; Mathur, Megha; Sikarwar, Shalini


    Textile effluents are major industrial polluters because of high color content, about 15% unfixed dyes and salts. The present paper is aimed to investigate and develop cheap adsorption methods for color removal from wastewater using waste materials activated carbon and activated rice husk-as adsorbents. The method was employed for the removal of Safranin-T and the influence of various factors such as adsorbent dose, adsorbate concentration, particle size, temperature, contact time, and pH was studied. The adsorption of the dye over both the adsorbents was found to follow Langmuir and Freundlich adsorption isotherm models. Based on these models, different useful thermodynamic parameters have been evaluated for both the adsorption processes. The adsorption of Safranin-T over activated carbon and activated rice husks follows first-order kinetics and the rate constants for the adsorption processes decrease with increase in temperature.

  15. Gasification of agricultural residues in a demonstrative plant: Vine pruning and rice husks.

    Biagini, Enrico; Barontini, Federica; Tognotti, Leonardo


    Tests with vine pruning and rice husks were carried out in a demonstrative downdraft gasifier (350 kW), to prove the reactor operability, quantify the plant efficiency, and thus extend the range of potential energy feedstocks. Pressure drops, syngas flow rate and composition were monitored to study the material and energy balances, and performance indexes. Interesting results were obtained for vine pruning (syngas heating value 5.7 MJ/m(3), equivalent ratio 0.26, cold gas efficiency 65%, power efficiency 21%), while poorer values were obtained for rice husks (syngas heating value 2.5-3.8 MJ/m(3), equivalent ratio 0.4, cold gas efficiency 31-42%, power efficiency 10-13%). The work contains also a comparison with previous results (wood pellets, corn cobs, Miscanthus) for defining an operating diagram, based on material density and particle size and shape, and the critical zones (reactor obstruction, bridging, no bed buildup, combustion regime).

  16. Synthesis and characterization of cellulose acetate from rice husk: eco-friendly condition.

    Das, Archana M; Ali, Abdul A; Hazarika, Manash P


    Cellulose acetate was synthesized from rice husk by using a simple, efficient, cost-effective and solvent-free method. Cellulose was isolated from rice husk (RH) using standard pretreatment method with dilute alkaline and acid solutions and bleaching with 2% H2O2. Cellulose acetate (CA) was synthesized successfully with the yield of 66% in presence of acetic anhydride and iodine as a catalyst in eco-friendly solvent-free conditions. The reaction parameters were standardized at 80 °C for 300 min and the optimum results were taken for further study. The extent of acetylation was evaluated from % yield and the degree of substitution (DS), which was determined by (1)H NMR and titrimetrically. The synthesized products were characterized with the help modern analytical techniques like FT-IR, (1)H NMR, XRD, etc. and the thermal behavior was evaluated by TGA and DSC thermograms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Probiotic activity of lignocellulosic enzyme as bioactivator for rice husk degradation

    Lamid, Mirni; Al-Arif, Anam; Warsito, Sunaryo Hadi


    The utilization of lignocellulosic enzyme will increase nutritional value of rice husk. Cellulase consists of C1 (β-1, 4-glucan cellobiohydrolase or exo-β-1,4glucanase), Cc (endo-β-1,4-glucanase) and component and cellobiose (β-glucocidase). Hemicellulase enzyme consists of endo-β-1,4-xilanase, β-xilosidase, α-L arabinofuranosidase, α-D-glukuronidaseand asetil xilan esterase. This research aimed to study the activity of lignocellulosic enzyme, produced by cows in their rumen, which can be used as a bioactivator in rice husk degradation. This research resulted G6 and G7 bacteria, producing xylanase and cellulase with the activity of 0.004 U mL-1 and 0.021 U mL-1; 0.003 ( U mL-1) and 0.026 (U mL-1) respectively.

  18. Mechanical Properties of Concrete Using Eggshell Ash and Rice Husk Ash As Partial Replacement Of Cement

    Afizah Asman Nurul Shahadahtul


    Full Text Available This research was carried out to determine the optimum percentage of eggshell ash and rice husk ash (RHA as partial cement replacement. The samples were tested for its mechanical properties by using concrete grade G30 with cube mould (100 mm × 100 mm × 100 mm and prisms (100 mm × 100 mm × 500 mm. The samples were mixed with eggshell ash and RHA admixture with different proportions (2%:8%, 4%:6%, 6%:4%. Several types of test were conducted towards the samples, which are the slump test, compressive and flexural test. Based on previous researches, the strength of concrete reduced as replaced with eggshells. Most of the researches show the similar trend when partial cement is replaced using eggshell ash. Thus, to increase the strength, an admixture which has pozzolanic reactivity called rice husk ash (RHA is introduced into mix design which has been proved can help to improve the strength of concrete.

  19. Study of the Mechanical and Morphology Properties of Recycled HDPE Composite Using Rice Husk Filler

    Jia Ying Tong


    Full Text Available WPCs are being used in a large number of applications in the automotive, construction, electronic, and aerospace industries. There are an increasing number of research studies and developments in WPC technology involving rice husk as fillers. This study investigated the effects of different compositions of rice husk (RH filler on the mechanical and morphological properties of recycled HDPE (rHDPE composite. The composites were prepared with five different loading contents of RH fibers (0, 10, 20, 30, and 40 wt% using the twin screw extrusion method. Maleic acid polyethylene (MAPE was added as a coupling agent. Results showed that tensile and flexural properties improved with increasing RH loading. However, the impact strength of the composites decreased as the RH loading increased. SEM micrographs revealed good interfacial bonding between the fiber and polymer matrix.

  20. Use of Rice Husk-Bark Ash in Producing Self-Compacting Concrete

    Sumrerng Rukzon


    Full Text Available This paper presents the use of blend of Portland cement with rice husk-bark ash in producing self-compacting concrete (SCC. CT was partially replaced with ground rice husk-bark ash (GRHBA at the dosage levels of 0%–40% by weight of binder. Compressive strength, porosity, chloride penetration, and corrosion of SCC were determined. Test results reveal that the resistance to chloride penetration of concrete improves substantially with partial replacement of CT with a blend of GRHBA and the improvement increases with an increase in the replacement level. The corrosion resistances of SCC were better than the CT concrete. In addition, test results indicated that the reduction in porosity was associated with the increase in compressive strength. The porosity is a significant factor as it affects directly the durability of the SCC. This work is suggested that the GHRBA is effective for producing SCC with 30% of GHRBA replacement level.

  1. Synthesis, characterization and catalytic activity of carbon-silica hybrid catalyst from rice straw

    Janaun, J.; Safie, N. N.; Siambun, N. J.


    The hybrid-carbon catalyst has been studied because of its promising potential to have high porosity and surface area to be used in biodiesel production. Silica has been used as the support to produce hybrid carbon catalyst due to its mesoporous structure and high surface area properties. The chemical synthesis of silica-carbon hybrid is expensive and involves more complicated preparation steps. The presence of natural silica in rice plants especially rice husk has received much attention in research because of the potential as a source for solid acid catalyst synthesis. But study on rice straw, which is available abundantly as agricultural waste is limited. In this study, rice straw undergone pyrolysis and functionalized using fuming sulphuric acid to anchor -SO3H groups. The presence of silica and the physiochemical properties of the catalyst produced were studied before and after sulphonation. The catalytic activity of hybrid carbon silica acid catalyst, (H-CSAC) in esterification of oleic acid with methanol was also studied. The results showed the presence of silica-carbon which had amorphous structure and highly porous. The carbon surface consisted of higher silica composition, had lower S element detected as compared to the surface that had high carbon content but lower silica composition. This was likely due to the fact that Si element which was bonded to oxygen was highly stable and unlikely to break the bond and react with -SO3H ions. H-CSAC conversions were 23.04 %, 35.52 % and 34.2 7% at 333.15 K, 343.15 K and 353.15 K, respectively. From this research, rice straw can be used as carbon precursor to produce hybrid carbon-silica catalyst and has shown catalytic activity in biodiesel production. Rate equation obtained is also presented.

  2. Rice Husk Ash Derived Zeolite Blended with Water Hyacinth Ash for Enhanced Adsorption of Cadmium Ions

    G. W. Mbugua; H. M. Mbuvi; J. W. Muthengia


    In order to helpcurtail or imposesustained control to the offensive water hyacinth plant,it is essential to explore ways of generatingwater remediation materials from it. In the current study, the capacity and efficacy of water hyacinth ash (WHA),its insoluble residue (WHAR) and rice husk ash (RHA)to remove cadmium ionsand methylene blue from contaminated water was investigated. Mixtures of the two ashes were used to formulatezeolitic materialsby hydrothermal reactions. Material A, ZMA was pr...

  3. Design of multiple-layer microwave absorbing structure based on rice husk and carbon nanotubes

    Seng, Lee Yeng; Wee, F. H.; Rahim, H. A.; AbdulMalek, MohamedFareq; You, Y. K.; Liyana, Z.; Ezanuddin, A. A. M.


    This paper presents a multiple-layered microwave absorber using rice husk and carbon nanotube composite. The dielectric properties of each layer composite were measured and analysed. The different layer of microwave absorber enables to control the microwave absorption performance. The microwave absorption performances are demonstrated through measurements of reflectivity over the frequency range 2-18 GHz. An improvement of microwave absorption application as wideband electromagnetic wave absorbers.

  4. Rice husk-derived graphene with nano-sized domains and clean edges.

    Muramatsu, Hiroyuki; Kim, Yoong Ahm; Yang, Kap-Seung; Cruz-Silva, Rodolfo; Toda, Ikumi; Yamada, Takumi; Terrones, Mauricio; Endo, Morinobu; Hayashi, Takuya; Saitoh, Hidetoshi


    A new synthetic method is demonstrated for transforming rice husks into bulk amounts of graphene through its calcination and chemical activation. The bulk sample consists of crystalline nano-sized graphene and corrugated individual graphene sheets; the material generally contains one, two, or a few layers, and corrugated graphene domains are typically observed in monolayers containing topological defects within the hexagonal lattice and edges. Both types of graphenes exhibit atomically smooth surfaces and edges.


    P.I. Oghome


    Full Text Available In this research work, comparative analysis of Oxalic acid produced from Rice husk and Paddy was carried out in order to ascertain which waste sample produced a better yield. Nitric acid oxidation of carbohydrates was the method adopted in the production. The variable ratios of HNO3:H2SO4 used were 80:20, 70:30, 60:40, and 50:50. The variable ratio of 60:40 gave the maximum yield and at a maximum temperature of 75oC. Rice husk sample gave a percentage yield of 53.2, 64.4, 81.0, and 53.3 at temperatures of 55 oC, 65 oC, 75 oC, and 85 oC respectively. In the case of paddy a percentage yield of 53.1, 64.0, 79.9, and 52.8 at temperatures of 55 oC, 65 oC, 75 oC, and 85 oC were obtained respectively. The plots between yield and temperature at different variable ratios illustrate the dependence of yield on temperature, which was similar to a parabolic relationship and the peak value (yield was at 75 oC above which it decreased. The properties of oxalic acid from both sources were very close and compared favourably with literature. In comparing the yield, oxalic acid produced from Rice husk gave higher yield than that from Paddy.

  6. Investigation on Thermal Properties of Composite of Rice Husk, Corncob and Baggasse for Building Thermal Insulation

    Kyauta E.E. Dauda D.M


    Full Text Available The thermal properties of some Agricultural waste ( Rice Husk, Bagasse and Corncob was investigated with the purpose of determining their use as insulators. Using varied composite percentages of each sample wastes at increasing and decreasing quantities to determine best mixtures has assisted in accurate recommendation. The work has explored the potentials for using composite samples of Rice Husk, Bagasse and Corncob as materials for thermal insulation, a solution which offers a reduction in resource use, promote recycle of the wastes, less dependent on toxic chemical types in wood/cellulose based insulators, in addition to reducing energy consumed by altering internal air conditions.The criteria for evaluation includes experimental determination of Thermal Conductivities and Specific Heat Capacities for composites samples and other dependable properties.The results from evaluations have identified that sample G with 0.231Wm-1 k -1 and 22.114m-1 is the best mixed with more rice husk and considerable percentage of bagasse to less percentage of corncob

  7. Kinetics, thermodynamics and mechanistic studies of carbofuran removal using biochars from tea waste and rice husks.

    Vithanage, Meththika; Mayakaduwa, S S; Herath, Indika; Ok, Yong Sik; Mohan, Dinesh


    This study reports the thermodynamic application and non-linear kinetic models in order to postulate the mechanisms and compare the carbofuran adsorption behavior onto rice husk and tea waste derived biochars. Locally available rice husk and infused tea waste biochars were produced at 700 °C. Biochars were characterized by using proximate, ultimate and surface characterization methods. Batch experiments were conducted at 25, 35, and 45 °C for a series of carbofuran solutions ranging from 5 to 100 mg L(-1) with a biochar dose of 1 g L(-1) at pH 5.0 with acetate buffer. Molar O/C ratios indicated that rice husk biochar (RHBC700) is more hydrophilic than tea waste biochar (TWBC700). Negative ΔG (Gibbs free energy change) values indicated the feasibility of carbofuran adsorption on biochar. Increasing ΔG values with the rise in temperature indicated high favorability at higher temperatures for both RHBC and TWBC. Enthalpy values suggested the involvement of physisorption type interactions. Kinetic data modeling exhibited contribution of both physisorption, via pore diffusion, π*-π electron donor-acceptor interaction, H-bonding, and van der Waals dispersion forces and chemisorption via chemical bonding with phenolic, and amine groups. Equilibrium adsorption capacities of RHBC and TWBC determined by pseudo second order kinetic model were 25.2 and 10.2 mg g(-1), respectively.

  8. Hydro-Physical Properties of a Typic Hapludult under the Effect of Rice Husk Ash

    Gláucia Oliveira Islabão


    Full Text Available ABSTRACT The combustion of rice husk generates a partially burnt mixture called rice husk ash (RHA that can be used as a source of nutrients to crops and as a conditioner of soil physical properties. The objective of this study was to evaluate the effect of RHA levels on the hydro-physical properties of a Typic Hapludult. The experimental design was composed of random blocks with four replications, which comprised plots of 24 m2 and treatments with increasing RHA rates: 0, 40, 80 and 120 Mg ha-1. Undisturbed soil samples were collected in the soil layers of 0.00-0.10 and 0.10-0.20 m after nine months of RHA application, using steel cylinders (0.03 m of height and 0.047 m of diameter. These samples were used to determine soil bulk density (Bd, total soil porosity (TP, soil macroporosity (Ma, soil microporosity (Mi and the available water capacity (AWC. Disturbed soil samples were collected to determine the stability of soil aggregates in water, mean weight diameter of water stable aggregates (MWD, and soil particle size distribution. The results show that, as the RHA rate increased in the soil, Bd values decreased and TP, Ma and MWD values increased. No effect of RHA was found on Mi and AWC values. The effects of RHA on the S parameter (Dexter, 2004, precompression stress and compression index (Dias Junior and Pierce, 1995 values are consistent those shown for density and total porosity. Rice husk ash was shown to be an efficient residue to improve soil physical properties, mainly at rates between 40 and 80 Mg ha-1. Rice husk ash reduces bulk density and increases total porosity, macroporosity and soil aggregation, but does not affect microporosity, field capacity, permanent wilting point, and available water capacity of the soil. The effect of rice husk ash on the S parameter, precompression stress and index compressibility coefficient values are consistent with those observed for the bulk density and total porosity.

  9. Studies on development of new functional natural materials from agricultural products - Technology developments for ceramic powders and materials from rice phytoliths

    Kang, Dae Kap; Kim, Yong Ik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Yoon, Nang Kyu; Seong, Seo Yong [Myongseong Ceramics Com., Taejon (Korea, Republic of); Ryu, Sang Eun [Bae Jae Univ., Taejon (Korea, Republic of); Lee, Jae Chun [Myungji Univ., Seoul (Korea, Republic of)


    Based on an estimation of annual rice production of 5.2 million tons, rice husks by-production reaches to 1.17 million tons per year in Korea. Distinguished to other corns, rice contains a lot of Si; 10-20% by weight in rice husks calculated as silica. The aim of this research project is to develop technologies for ceramic powders and materials utilizing the silica in rice husks called phytoliths. In this first year research, researches of the following subjects were performed; material properties of rice husks, milling of rice husks, acid treatments, oxidations at low and high temperatures, sintering and crystalization of amorphous silica, low temperature carburization, formation of silicon carbide whiskers, and brick lightening method using milled rice husks. 11 tabs., 49 figs., 75 refs. (Author).

  10. Esterification free fatty acid in sludge palm oil using ZrO2/SO42- - rice husk ash catalyst

    Hidayat, Arif; Sutrisno, Bachrun


    Indonesia, as one of the biggest palm oil producers and exporters in the world, is producing large amounts of low-grade oil such as sludge palm oil (SPO) from palm oil industries. The use of SPO can lower the cost of biodiesel production significantly, which makes SPO a highly potential alternative feedstock for biodiesel production. In this paper, the esterification of free fatty acid on sludge palm oil was studied using rice husk ash as heterogeneous solid catalysts. Heterogeneous solid catalysts offer significant advantages of eliminating separation, corrosion, toxicity and environmental problems. In this paper the esterification of SPO, a by-product from palm oil industry, in the presence of modified rice husk ash catalysts was studied. The rice husk ash catalysts were synthesized by impregnating of Zirconia (Zr) on rice husk ash followed by sulfonation. The rice husk ash catalysts were characterized by using different techniques, such as FT-IR, XRD, and porous analysis. The effects of the mass ratio of catalyst to oil (1 - 10%), the molar ratio of methanol to oil (4:1 - 10:1), and the reaction temperature (40 - 60°C) were studied for the conversion of free fatty acids (FFAs) to optimize the reaction conditions. The results showed that the optimal conditions were an methanol to oil molar ratio of 10:1, the amount of catalyst of 10%w, and reaction temperature of 60°C.

  11. Fabrication and characterization of rice husk and coconut shell charcoal based bio-briquettes as alternative energy source

    Yuliah, Y.; Kartawidjaja, M.; Suryaningsih, S.; Ulfi, K.


    Rice husk and coconut shell have been disposed or burned as waste. As biomass, both of materials are the potential sources of carbon which can be utilized as alternative energy sources. The energy content can be exploited more intensively when packaged in a brief and convenient. In this work, the mixtures of rice husks and coconut shells charcoal were prepared as briquettes. After going through the carbonization process, several measurements have been taken to find out the factors that determine the value of heat energy contains by each component of the charcoals. The basic ingredients briquettes prepared from rice husk and coconut shell charcoal with varying composition and addition of tapioca starch gradually as adhesive material to obtain briquettes in solid with the maximum heat energy content. After going through pressing and drying process, the briquettes with 50:50 percent of composition and the 6% addition of adhesive was found has the highest heat energy content, equal to 4966 cal/g.

  12. A preliminary study for removal of heavy metals from acidic synthetic wastewater by using pressmud-rice husk mixtures

    Ahmad, H.; Ee, C. J.; Baharudin, N. S.


    The study was carried out to evaluate the effect of combining pressmud and rice husk in the removal efficiencies of heavy metals in acidic synthetic wastewater. The ratios of pressmud to rice husk were varied at different percentages of weight ratio (0%, 20%, 40%, 60% 80% and 100%) and removal of heavy metals concentrations was observed. The result showed that the removal efficiency was increased with the addition of pressmud by up to almost 100%. Pressmud alone was able to remove 95% to 100% of heavy metals while rice husk alone managed to remove only 10% to 20% of heavy metals. The study also demonstrated that pressmud behaved as a natural acid neutralizer. Hence, the initial pH of the synthetically prepared acidic wastewater which was below 2 also was increased to pH ranging from 6 to 8.




    Full Text Available Substituting waste materials in construction is well known for conservation of dwindling resources and preventing environmental and ecological damages caused by quarrying and depletion of raw materials. Many researches had shown that some of these wastes have good pozzolanic properties that would improve the quality of concrete produced. One such waste material is agricultural waste rice husk, which constitute about one-fifth of 600 million tonnes of rice produced annually in the world. The RHA obtained by burning the rice husk in the ferrocement furnace and used as a cement replacement material. The use of this supplementary cementing material is expected to meet the increase in demand of cement, as the current world cement production of approximately 1.2 million tonnes is expected to grow exponentially to about 3.5 billions tonnes per year by 2015. This paper reports the results of durability performance conducted on the normal strength concrete specimens of 30 N/mm2 containing 20% or 30% RHA by cement weight, with or without addition of superplasticizer. The results show that replacement of cement with RHA lowers initial surface absorption, lowers the permeability, lowers the absorption characteristics, longer time taken for the capillary suction resulted in lower sorptivity value, lower water permeability and increase the resistance of concrete to chloride ion penetration in comparison with the OPC control concrete. The present investigations revealed that incorporation RHA significantly improve the absorption and permeability characteristics of concrete.


    Adebisi Ridwan


    Full Text Available This paper compares the stabilizing effects of three different materials, namely: rice husk ash, powdered glass, and cement on the properties of lateritic soil. The basic properties of the lateritic soil were first obtained through colour, moisture content determination, specific gravity, particle size distribution and Atterberg limits tests. Each of the stabilizing materials was then mixed with the lateritic soil in varying percentages of 2.5%, 5%, 7.5%, 10%, 12.5% and 15% by weight of the soil. Thereafter, compaction and California bearing ratio (CBR tests were carried out on the sample mixes to determine the effects of the materials on the lateritic soil. Chemical tests were also carried out on the samples to determine their percentage oxides composition. The compaction test showed that the highest maximum dry densities (MDD obtained for the mixed samples were 2.32 g/cm3 (at 2.5% cement addition, 2.28g/cm3 (at 5% powdered glass (PG addition and 2.18 g/cm3 (at 5% rice husk ash (RHA addition with corresponding optimum moisture contents (OMC of 10.06%, 14.3% and 12.31% respectively. The CBR tests showed that the CBR values increased in all cases as the materials were added with those of the cement and powdered glass giving the highest values and showing close semblance under unsoaked conditions. The chemical test showed that the significant oxides present in the cement, powdered glass and rice husk ash were CaO (53.60%, SiO2 (68.45% and SiO2 (89.84% respectively.

  15. The influence of rice husk and tobacco waste biochars on soil quality

    Amir Hamzah


    Full Text Available Heavy metal pollution in agricultural land threatens soil and food quality. Soil pollution could be remediate using biochar, but the effectiveness of biochar on soil quality improvement is determined by types of feedstock and pyrolysis temperature. This study was aimed to explore the effect of different types of biochar on soil properties.  Biochar from rice husk and tobacco waste was applied to soil contaminated with lead and mercury. This study was conducted at Sumber Brantas, Malang East Java, and used a completely randomized design with three replicates. Heavy metals content was measured using AAS. The results of measurements were analyzed using analysis of variance at 5% and 1% significance levels. The initial analysis of the soil properties at the research site showed that the soil nutrient status was low, i.e. N (0.2 %, K (0.50 cmol+/kg, and CEC (5.9 me/100g respectively, but soil pH was neutral (6.8. The research site also has crossed the threshold of heavy metal content for Hg (0.5 ppm, Pb (25.22 ppm, Cd (1.96 ppm, and As (0.78 ppm. Biochar added had a positive influence on soil characteristics improvement. It could increase the content of organic C, i.e. 35.12% and 31.81% and CEC (cation exchange capacity, i.e.30.56 me/100g and 28.13 me/100 g for rice husk biochar and tobacco waste biochar, respectively.  However, N, P, and K contents were low i.e. N ( 0.33 and 0.30 %; P2O5 (148.79 and 152 ppm; K (1.58 and 2.11 mg/100g for rice husk biochar and tobacco waste biochar, respectively.


    Monik Kasman


    Full Text Available This work was focused on iron adsorption by rice husk. The use of rice husk for the removal of iron from aqueous solution at different contact time, pH, adsorbent doses and initial iron concentration was investigated. This study was also aimed to recognize the mechanisms that govern iron removal, and to find an appropriate isotherm and kinetic model in batch process. The equilibrium adsorption isotherms have been analyzed by Freundlich and Langmuir model. The pseudo-first, and pseudo-second order kinetic models have been used to investigate the mechanism of adsorption and potential rate controlling steps. The equilibrium data fitted well to Freundlich model and mechanism of adsorption described well to pseudo first order kinetic. The iron adsorption process was highly dependent on pH, dosage and initial concentration dependent. Iron was reduced higher with decrease in iron concentration and increase in rice husk dosage. The suitable contact time for iron removal was found to be 180 minutes.ABSTRAKFokus penelitian ini adalah adsorpsi besi dengan menggunakan adsorban sekam padi. Eksperimen dilakukan dengan memvariasikan waktu kontak, nilai pH, dosis adsorban dan konsentrasi awal besi. Penelitian bertujuan untuk mengamati mekanisme yang mempengaruhi penyisihan besi dan menemukan model isothermal dan kinetika yang tepat untuk proses adsorpsi besi. Kesetimbangan model isotermal dianalisis dengan modelFreundlich dan Langmuir. Model kinetika order pertama dan kedua digunakan untuk mengamati mekanisme adsorpsi dan tahap kontrol kecepatan potensial. Hasil penelitian menunjukan bahwa model adsorpsi yang tepat untuk penyisihan besi adalah model Freundlich dan mekanisme adsorpsi yang sesuai adalah kinetika orde pertama. Prosesadsorpsi besi sangat dipengaruhi oleh pH, dosis adsorban dan konsentrasi awal besi. Persentase penyisihan besi meningkat jika konsentrasi awal besi menurun dan dosis adsorban meningkat. Hasil penelitian menunjukan bahwa adsorpsi besi

  17. Research on the Adsorption of Methylene Blue with Rice Husk Ash Aided by Ion Beam Etching Technique


    [Objective] The aim was to study the mechanism of the removal effect of methylene blue(MB) by rice husk ash(RHA).[Method] The effects of contact time and pH on the adsorption of MB by rice husk ash were investigated,and the mechanism was discussed.[Result] RHA exhibited a remarkable ability on the adsorption of MB.The process of adsorption reached the equilibrium after 30 min,at about pH 9.The adsorption effect was explored with the aid of ion beam etching technique,which displayed that there were two main ...

  18. Physical and Thermal Characterization of Alkali Treated Rice Husk Reinforced Polypropylene Composites

    Ismat Zerin Luna


    Full Text Available Rice husk (RH reinforced polypropylene- (PP- based composites were prepared by compression molding. The RH was treated with sodium hydroxide solution (1 wt%; then composites were prepared using varying percentages of RH (5 to 20 wt%. The thermomechanical, spectroscopic, and morphological properties of the prepared composites (RH-PP were investigated. The scanning electron microscopic (SEM analysis showed better interfacial adhesion between alkali treated RH and the matrix PP. The Fourier Transform Infrared (FTIR spectra confirmed the chemical bonding.The results revealed that physical properties as well as thermal stability of the composites improved significantly with the addition of alkali treated RH in PP matrix.

  19. Sequestering of thorium ions from aqueous media on rice husk. Equilibrium, kinetic and thermodynamic studies

    Zafar, Shagufta; Mirza, Muhammad Latif [The Islamia University of Bahawalpur (Pakistan). Dept. of Chemistry; Khalid, Nasir [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.


    The adsorption behaviour of thorium on rice husk has been studied by optimizing different parameters like nature of electrolyte, amount of adsorbent, equilibration time, metal concentration, and temperature, employing batch method and radiotracer technique. Maximum adsorption was observed at 0.0001 mol L{sup -1} HNO{sub 3}, using 0.1 g of adsorbent for 4 cm{sup 3} of 5.19 x 10{sup -5} mol L{sup -1} of Th{sup +4} solution in fifteen minutes equilibration time. The adsorption phenomenon was verified by FTIR, SEM and EDX techniques. The adsorption data was well fitted to Freundlich, Langmuir and Dubinin-Radushkevich isotherm equations. The characteristic Freundlich constants i.e. 1/n = 0.528 ± 0.019 and K = 4.88 x 10{sup -4} ± 1.29 x 10{sup -5} mol g{sup -1} whereas the Langmuir constants Q{sub m} = (4.159 ± 0.234) x 10{sup -6} mol g{sup -1} and K{sub L} = (3.627 ± 0.328) x 10{sup 4} dm{sup 3} mol{sup -1} have been computed for the sorption system. The sorption free energy was found to be 11.24 ± 0.211 kJ mol{sup -1} showing chemisorption nature of interaction between thorium and rice husk. The results showed that thorium adsorption on rice husk follows pseudo 2{sup nd} order with rate constant = 1.448 g mg{sup -1} min{sup -1}. The determined negative values of ΔG indicated spontaneity of the process, whereas the positive values of ΔH and ΔS confirmed endothermic nature and increased randomness during the adsorption process respectively. The removal of Th{sup +4} ions from spiked tap water was checked by employing the optimized experimental parameters which indicated that rice husk is a good adsorbent for thorium ions and may be used for waste management of radionuclides.

  20. Silica Derived from Burned Rice Hulls

    M.F. de Souza


    Full Text Available Three new processes to obtain silica having high specific surface area from burned pre-treated rice hulls are presented and discussed. These procedures allow for the simultaneous recovery of biomass energy and the production of high quality silica at thermoelectric plants, without the risk of using corrosive substances in the burning process. The first method involves treatment of the hull with hot organic acid solutions before burning, the second with boiling water, both using an autoclave at temperatures close to150 °C, while the third method renders the hull fragile by treating it at 250 °C and reducing it to a fine powder before burning. The first two methods result in white amorphous silica that can show 500 m²/g of specific surface area. The third method, which does not remove the alkaline elements from the hull, produces an amorphous gray carbon-free powder whose specific surface area can be as high as 250 m²/g. An investigation of the specific surface area of the prepared silica indicates the alkaline elements are not mixed with silica in the hulls or combined as insoluble compounds. A comparison is made of these processes and the dissolution of silica by sodium hydroxide solutions is discussed.

  1. 具有高比表面积的稻壳灰的制备及其化学活性的研究%Study on Preparation of Rice Husk Ash with High Specific Surface Area and Its Chemical Reactivity

    冯庆革; 林清宇; 童张法; S.Sugita


    Preparation of rice husk ash with high specific surface area and chemical reactivity of the product are reported in this paper. The amorphous rice husk ash with high specific surface area of 311 m2·g-1 was produced by heating acid treated rice husk at 700℃ for 4 h. The isotherms of rice husk ash are similar in shape to type Ⅱof Brunaner's classification with mesopores being predominant. The rice husk ash has a high chemical reactivity,especially that pretreated with acid. This chemical reactivity depends on ashing temperature and pretreatment conditions. There is an exponential relation between the specific surface area of rice husk ash and the change in the conductivity of saturated Ca(OH)2 solution with rice husk ash, from which the specific surface area can be known according to the conductivity change.

  2. Comparing dry ashing and wet oxidation methods. The case of the rice husk (Oryza sativa L.).

    Sun, Xiuping; Wu, Yan; Wang, Changsui; Hill, David V


    Experiments were conducted to determine the effects that different methods for the preparation of modern plant samples have on the resulting phytoliths using rice husks (Oryza sp.). The methods that are commonly used in phytolith extraction include (1) dry ashing, (2) acid extraction (3) a combination of both techniques. The results showed that processing methods have an impact on the morphology of two subspecies of rice phytoliths, dry ashing producing more conjoined cell phytoliths or multicells phytoliths than acid extraction. Using a combination of both methods resulted in the presence of fewer conjoined cells than dry ashing alone, but more conjoined cells than acid extraction. Alternative explanations are proposed to explain the formation of conjoined phytolith cells. Copyright © 2012 Wiley Periodicals, Inc.

  3. Effect of rice husk gasification residue application on herbicide behavior in micro paddy lysimeter.

    Ok, Junghun; Pisith, Sok; Watanabe, Hirozumi; Thuyet, Dang Quoc; Boulange, Julien; Takagi, Kazuhiro


    Effects of rice husk gasification residues (RHGR) application on the fate of herbicides, butachlor and pyrazosulfuron-ethyl, in paddy water were investigated using micro paddy lysimeters (MPLs). The dissipation of both herbicides in paddy water was faster in the RHGR treated MPL than in the control MPL. The average concentrations of butachlor and pyrazosulfuron-ethyl in paddy water in the lysimeter treated with RHGR during 21 days were significantly reduced by 51% and 48%, respectively, as compared to those in the lysimeter without RHGR application. The half-lives (DT50) of butachlor in paddy water for control and treatment were 3.1 and 2.3 days respectively, and these values of pyrazosulfuron-ethyl were 3.0 and 2.2 days, respectively. Based on this study, RHGR application in rice paddy environment is an alternative method to reduce the concentration of herbicide in paddy field water and consequently to reduce potential pollution to aquatic environment.

  4. Kinetic and Thermodynamics Studies the Adsorption of Phenol on Activated Carbon from Rice Husk Activated by ZnCl2

    Andi Muhammad Anshar


    Full Text Available The purpose of this study was to investigate the adsorption ability of activated carbon from rice husk in adsorbing phenol. Activated carbon used was in this studies burning risk husk at 300 and 400oC and then activated by 10% of ZnCl2. The from activated carbon was characterized using an Infrared Spectrometer, an X-ray diffraction, an Scanning Electron Microscope, and a gas sorption analyzer. The best activated carbon for adsorbing phenol was the activated carbon that prodused from the burning of rice husk at a temperature 400oC and activated with 10% of ZnCl2 for 24 hours. Adsorption capacity of the best activated carbon was 3.9370 mg/g adsorbent with Gibbs free energy of -25.493 kJ/mol.

  5. Improving Impact Strength Recovery of Fractured and Healed Rice Husks Fibre Reinforced Polypropylene Composites.

    Odhong, O.V.E


    Full Text Available Rice husks fibre reinforced polypropylene composite (rhfrpc is a natural plant fibre reinforced polymer composite having advantages of high strength, light weight and affordability. They are commonly used for light load structural and non structural applications. They are mainly used as particle boards, for fencing post, roofing tiles, for interiors of car and aircrafts among other usages. This material once cracked by impact forces cannot be repaired using traditional repair methods for engineering materials such as metals or other composites that can be repaired by welding or by patch repair methods respectively, thus a method of repair of rice husks fibre reinforced polypropylene composites by refilling the damaged volume by injection of various healing agents has been investigated. The composite coupons were produced by injection moulding, cooled sufficiently and prepared for charpy impact tests. Test results for pristine coupons were a maximum of 48 J/mm2 . The destroyed coupons were then subjected to healing in a fabricated healing fixture. Healing agents such as epoxy resin, ethyl cyanoacrylate, and tannin gum have been investigated for their use as possible healing agents to fill the damaged volume and perform healing action at the fractured surfaces. The impact test results were recorded and compared with those of unhealed pristine coupons. The recovered strengths were a maximum of 60 J/mm2 translating into a 125% impact strength recovery, and this is good enough for the healed composites to be recommended for reuse in their second lives of their respective original functions.

  6. Effects of water washing and torrefaction pretreatments on rice husk pyrolysis by microwave heating.

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan; Liu, Xinzhi; Zhu, Shuguang


    The influences of water washing, torrefaction and combined water washing-torrefaction pretreatments on microwave pyrolysis of rice husk samples were investigated. The results indicated that the process of combined water washing-torrefaction pretreatment could effectively remove a large portion of inorganics and improve the fuel characteristics to a certain extent. The gas products were rich in combustible compositions and the syngas quality was improved by pretreatment process. The liquid products contained less moisture content, acids and furans, while more concentrated phenols and sugars from microwave pyrolysis of rice husk after pretreatments, especially after the combined water washing-torrefaction pretreatment. Biochar, produced in high yield, has the alkaline pH (pH 8.2-10.0) and high surface area (S(BET) 157.81-267.84 m(2)/g), they have the potential to be used as soil amendments. It is noteworthy that water washing increased the pore surface area of biochar, but torrefaction reduced the pore surface area.

  7. Effect of Rice Husk and Diatomite on the Insulating Properties of Kaolin - Clay Firebricks

    Emmanuel Ogo ONCHE


    Full Text Available This work was carried out to investigate the effect of rice husk and diatomite on the insulating properties of kaolin-clay firebrick. Five firebrick samples of different compositions were fired at 900°C, 1000°C, 1100°C, and 1200°C. Samples A-E are all insulating firebricks that can withstand temperatures ranging from 900°C to 1200°C since none of the samples crumbled during firing. The results showed that they all had good insulating characteristics with their highly porous structure making them suitable for backup insulation. Mixing ratios of 3:2:4:1 representing weight in grams of kaolin, plastic clay, rice husk and diatomite respectively for sample D gave the optimum performance values in terms of modulus of rupture, apparent porosity, apparent density, bulk density, and thermal conductivity at all temperatures. At 1200°C, the values are 22.57kgf/cm2 for modulus of rupture, 98.25% for apparent porosity, 2.38g/cm3 for apparent density, 1.11g/cm3 for bulk density, and 0.038w/mK for thermal conductivity.

  8. Briquettes of rice husk, polyethylene terephthalate (PET), and dried leaves as implementation of wastes recycling

    Hariyanto, Sucipto; Usman, Mohammad Nurdianfajar; Citrasari, Nita


    This research aim is to determine the best briquettes as implementation of wastes recycle based on scoring method, main component composition, compressive strength, caloric value, water content, vollatile content, and ash content, also the suitability with SNI 01-6235-2000. Main component that used are rice husk, 2mm and 6 mm PET, and dried leaves. Composition variation in this research are marked as K1, K2, K3, K4, and K5 with 2 mm PET plastic and K1, K2, K3, K4, and K5 with 6 mm PET plastic. The total weight of the briquettes is 100 g and divided into 90% main components and 10% tapioca as binder. The compressive strength, caloric value, water content, vollatile content, and ash content were tested according to ASTM D 5865-04, ASTM D 3173-03, ASTM D 3175-02, ASTM D 3174-02. The tested results were used to determine the best briquette by scoring method, and the chosen briquettes is K2 with 6 mm PET plastic. The composition is 70% rice husk, 20% 6 mm PET plastic, and 10% dried leaves with the compressive strength, caloric value, water content, vollatile content, and ash content value is 51,55 kg/cm2; 5123 kal/g; 3,049%; 31,823%, dan 12,869%. The suitable value that meet the criteria according to SNI 01-6235-2000 is compressive strength, caloric value, water content, and ash content.

  9. Mechanical Behavior of Concrete Modified by Replacement of Cement by Rice Husk Ash

    M.M. Saravanan

    Full Text Available ABSTRACT Construction industry is in need of lump sum quantities of materials which has increased both their demand and price. The use of large quantities of cement leads to increasing CO2 emission and as a consequence, the greenhouse effect. Consumption of wastes and byproducts from various sources in the manufacture of concrete has gained a great deal of importance in present days. Various researches are currently being conducted concerning the use of such products in concrete. RHA is a carbon neutral green product. Lots of ways are being thought of for disposing them by making commercial use of this. Rice husk ash is a good super-pozzolan which can be used to make special concrete mixes. The rice husk ash has been taken for this present study due to its easy availability and effective pozzolonic properties that are expected to improve the mechanical strength properties of concrete. Concrete specimens were made for evaluation of Compressive, Split Tensile, Flexural strength and Stress-Strain Behavior of concrete. The tests were conducted at the age of 7 and 28 days. Generally all mixes containing RHA achieved better properties than the conventional mix without RHA. By the experimental investigation the recommendation is given for using optimum percentage of RHA in concrete.

  10. Esterification free fatty acid in palm fatty acid distillate using sulfonated rice husk ash catalyst

    Hidayat, Arif; Sutrisno, Bachrun


    Indonesia, as one of the biggest palm oil producers and exporters in the world, is producing large amounts of low-grade oil such as Palm Fatty Acid Distillate (PFAD) from palm oil industries. The use of PFAD can reduce the cost of biodiesel production significantly, which makes PFAD a highly potential alternative feedstock for biodiesel production. In this paper, the esterification of free fatty acid (FFA) on PFAD was studied using rice husk ash (RHA) as heterogeneous catalyst. The rice husk ash catalyst was synthesized by sulfonation using concentrated sulfuric acid. The RHA catalyst were characterized by using different techniques, such as porosity analysis, Fourier transform infrared (FT-IR) spectroscopy, total number of acid sites and elemental analysis. The effects of the molar ratio of methanol to PFAD (1-10%), the molar ratio of methanol to PFAD (4:1-10:1), and the reaction temperature (40-60°C) were studied for the conversion of FFA to optimize the reaction conditions. The results showed that the optimal conditions were an methanol to PFAD molar ratio of 10:1, the catalyst amount of 10 wt% of PFAD, and reaction temperature of 60°C.

  11. Upgrading of bio-oil from the pyrolysis of biomass over the rice husk ash catalysts

    Sutrisno, B.; Hidayat, A.


    The pyrolysis oils are complex mixtures of organic compounds that exhibit a wide spectrum of chemical functionality, and generally contain some water. Their direct use as fuels may present some difficulties due to their high viscosity, poor heating value, corrosiveness and instability. For possible future use as replacements for hydrocarbon chemical feedstocks and fuels, the liquids will require considerable upgrading to improve its characteristics. By esterification of the bio oil as the upgrading method, the properties of the bio-oil could be improved. In the paper, the upgrading of a bio-oil obtained by pyrolysis was studied over rice husk ash catalysts. The raw bio-oil was produced by pyrolysis of rice husk.From the experiment results, it can be concluded that the densities of upgraded bio-oil were reduced from 1.24 to 0.95, and the higherheating value increased from 16.0 to 27.2 MJ/kg and the acidity of upgraded bio-oil was also alleviated from 2.3 to 4.4. The results of gas chromatography-mass spectrometry (GC-MS) and FT-IR analysis showed that the ester compounds in the upgraded bio-oil increased. It is possible to improve the properties of bio-oil by esterifying the raw bio-oil.

  12. The Fabrication and Characterization of PCL/Rice Husk Derived Bioactive Glass-Ceramic Composite Scaffolds

    Farnaz Naghizadeh


    Full Text Available The present study was conducted to fabricate a 3D scaffold using polycaprolactone (PCL and silicate based bioactive glass-ceramic (R-SBgC. Different concentrations of R-SBgC prepared from rice husk ash (RHA were combined with PCL to fabricate a composite scaffold using thermally induced phase separation (TIPS method. The products were then characterized using SEM and EDX. The results demonstrated that R-SBgC in PCL matrix produced a bioactive material which has highly porous structure with interconnected porosities. There appears to be a relationship between the increase in R-SBgC concentration and increased material density and compressive modulus; however, increasing R-SBgC concentration result in reduced scaffold porosity. In conclusion, it is possible to fabricate a PCL/bioactive glass-ceramic composite from processed rice husk. Varying the R-SBgC concentrations can control the properties of this material, which is useful in the development of the ideal scaffold intended for use as a bone substitute in nonload bearing sites.

  13. Efeito da adição de cinza da casca de arroz em misturas cimento-casca de arroz Effect of the addition of rice husk ash in cement-rice husk mixtures

    Loris L. Zucco


    Full Text Available A casca de arroz e sua cinza são abundantes e renováveis, podendo ser empregadas na obtenção de materiais de construção alternativos. O aumento do consumo desses resíduos poderia ajudar a minimizar os problemas ambientais provenientes da sua eliminação inadequada. Este trabalho teve o objetivo de avaliar a utilização de cinzas como carga mineral (filler. Todavia, a casca de arroz interferiu quimicamente no comportamento das misturas à base de cimento. Assim, diferentes misturas cimento-casca de arroz, com e sem adição de cinzas, foram avaliadas, a fim de destacar a influência de seus componentes (casca; cinza que, de outra forma, poderiam ser excluídas ou subestimadas. Amostras cilíndricas (teste de compressão simples e de tração por compressão diametral e amostras extraídas das placas prensadas (teste de flexão e compressão paralela à superfície foram usadas para avaliar o comportamento das misturas e dos componentes casca e cinza. Os resultados dos ensaios mecânicos mostraram, em geral, que não houve diferença estatística entre as misturas, as quais estão associadas ao efeito químico supressivo da cinza da casca de arroz. A mistura da casca de arroz de 10 mm com o acréscimo de 35% das cinzas destaca-se por permitir o mais elevado consumo de casca e cinzas, reduzir 25% no consumo de cimento e permitir o confinamento (sem emissões para a atmosfera de cerca de 1,9 tonelada de CO2 por tonelada de cimento consumido, contribuindo, assim, para a redução da emissão de CO2, o que pode incentivar construções rurais sob o ponto de vista ecológico.The rice husk and its ash are abundant and renewable and can be used to obtain alternative building materials. An increase in the consumption of such waste could help minimize the environmental problems from their improper disposal. This study aimed to evaluate the use of ashes as a cargo mineral (filler. However, the rice husk chemically interferes in the conduct of the

  14. Performance comparison of constructed wetlands with gravel- and rice husk-based media for phenol and nitrogen removal.

    Tee, H C; Seng, C E; Noor, A Md; Lim, P E


    This study aims to compare the performance of planted and unplanted constructed wetlands with gravel- and raw rice husk-based media for phenol and nitrogen removal. Four laboratory-scale horizontal subsurface-flow constructed wetland units, two of which planted with cattail (Typha latifolia) were operated outdoors. The units were operated at a nominal hydraulic retention time of 7 days and fed with domestic wastewater spiked with phenol concentration at 300 mg/L for 74 days and then at 500 mg/L for 198 days. The results show that planted wetland units performed better than the unplanted ones in the removal and mineralization of phenol. This was explained by the creation of more micro-aerobic zones in the root zone of the wetland plants which allow a faster rate of phenol biodegradation, and the phenol uptake by plants. The better performance of the rice husk-based planted wetland compared to that of the gravel-based planted wetland in phenol removal could be explained by the observation that more rhizomes were established in the rice husk-based wetland unit thus creating more micro-aerobic zones for phenol degradation. The role of rice husk as an adsorbent in phenol removal was considered not of importance.

  15. Preparation of methacrylic acid-modified rice husk improved by an experimental design and application for paraquat adsorption

    Hsu, Shih-Tong, E-mail: [Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan (China); Chen, Lung-Chuan, E-mail: [Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan (China); Lee, Cheng-Chieh, E-mail: [Department of Environmental Engineering, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City 710, Tainan Hsien, Taiwan (China); Pan, Ting-Chung, E-mail: tcpan@mail.ksu.edutw [Department of Environmental Engineering, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City 710, Tainan Hsien, Taiwan (China); You, Bing-Xuan, E-mail: [Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan (China); Yan, Qi-Feng, E-mail: [Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan (China)


    Methacrylic acid (MAA) grafted rice husk was synthesized using graft copolymerization with Fenton's reagent as the redox initiator and applied to the adsorption of paraquat. The highest grafting percentage of 44.3% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 65.3% was calculated using the central composite design. Experimental results based on the recipes predicted from the statistical analysis are consistent with theoretical calculations. A representative polymethacrylic acid-g-rice husk (PMAA-g-rice husk) copolymer was hydrolyzed to a salt type and applied to the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of modified rice husk is 292.5 mg/g-adsorbent. This value exceeds those for Fuller's earth and activated carbon, which are the most common binding agents used for paraquat. The samples at various stages were characterized by solid-state {sup 13}C NMR spectroscopy.

  16. Determination of the intrinsic reactivities for carbon dioxide gasification of rice husk chars through using random pore model.

    Gao, Xiaoyan; Zhang, Yaning; Li, Bingxi; Zhao, Yijun; Jiang, Baocheng


    Rice husk is abundantly available and environmentally friendly, and char-CO2 gasification is of great importance for the biomass gasification process. The intrinsic reaction rates of carbon dioxide gasification with rice husk chars derived from different pyrolysis temperatures were investigated in this study by conducting thermogravimetric analysis (TGA) measurements. The effects of gasification temperature and reactant partial pressure on the char-CO2 gasification were investigated and the random pore model (RPM) was used to determine the intrinsic kinetic parameters based on the experimental data. The results obtained from this study show that the activation energy, reaction order and pre-exponential factor varied in the ranges of 226.65-232.28kJ/mol, 0.288-0.346 and 2.38×10(5)-2.82×10(5)1/sPa(n) for the rice husk chars pyrolyzed at 700-900°C, respectively. All the determination coefficients between the RPM predictions and experimental results were higher than 0.906, indicating the RPM is reliable for determining and evaluating the intrinsic reactivities of rice husk chars.

  17. Diversity in the Content of Some Nutritional Components in Husked Seeds of Three Wild Rice Species and Rice Varieties in Yunnan Province of China

    Zai-Quan CHENG; Xing-Qi HUANG; Yi-Zheng ZHANG; Jun QIAN; Ming-Zhi YANG; Cheng-Jun WU; Jia-Fu LIU


    In addition to rice (Oryza sativa L.) cultivars, there are three wild rice species, namely O.rufipogon Griff, O. officinalis Wall and O. granulata Baill, in Yunnan Province, China. Each species has different subtypes and ecological distributions. Yunnan wild rice species are excellent genetic resources for developing new rice cultivars. The nutritional components of the husked seeds of wild rice have not been investigated thus far. Herein, we report on the contents of total protein, starch, amylose, 17 amino acids, and five macro and five trace mineral elements in husked seeds from three wild rice species and six O. sativa cultivars. The mean (± SD) protein content in the husked rice of O. rufipogon, O. officinalis, and O. granulata was (14.5 ± 0.6)%, (16.3 ± 1. 1)%, and (15.3 ± 0.5)%, respectively. O. officinalis Ⅲ originating from Gengma had the highest protein content (19.3%). In contrast, the average protein content of six O. sativa cultivars was only 9.15%. The total content of 17 amino acids of three wild rice species was 30%-50% higher than that of the six cultivars. Tyrosine, lysine, and valine content in the three wild rice species was 34%-209% higher than that of the cultivars. However, the difference in total starch content among different O. sativa varieties or types of wild rice species was very small. The average amylose content of O. rufipogon, O. officinalis,and O. granulata was 12.0%, 9.7%, and 11.3%, respectively, much lower than that of the indica and japonica varieties (14.37%-17.17%) but much higher than that of the glutinous rice cultivars (3.89%). The sulfur, phosphorus, magnesium, zinc, and ferrite content in the three wild rice species was 30%-158% higher than that of the six cultivars. The considerable difference in some nutritional components among wild rice species and O. sativa cultivars represents a wide biodiversity of Yunnan Oryza species. Based on the results of the present study, it is predicted that some good genetic traits

  18. Evaluation of Mechanical Properties and Morphological Studies of Rice Husk (Treated/Untreated)-CaCO3 Reinforced Epoxy Hybrid Composites

    Verma, Deepak; Joshi, Garvit; Gupta, Ayush


    Natural fiber reinforced composites are a very popular area of research because of the easy availability and biodegradability of these fibers. The manufacturing of natural fiber composite is done by reinforcing fibers in the particulate form, fiber form or in woven mat form. Natural fiber composites also utilize industrial wastes as a secondary reinforcements like fly ash, sludge etc. By keeping all these point of views in the present investigation the effect of rice husk flour (chemically treated/untreated) and micro sized calcium carbonate with epoxy resin have been evaluated. The diameter of rice husk flour was maintained at 600 µm through mechanical sieving machine. The husk flour was chemically treated with NaOH (5 % w/v). Mechanical properties like hardness, flexural impact and compression strength were evaluated and found to be superior in modified or chemically treated flour as compared to unmodified or untreated flour reinforced composites. Scanning electron microscopy (SEM) study was also undertaken for the developed composites. SEM study shows the distribution of the rice husk flour and calcium carbonate over the matrix.

  19. Nanoporous Activated Carbon Derived from Rice Husk for High Performance Supercapacitor

    Huaxing Xu


    Full Text Available Nanoporous activated carbon material was produced from the waste rice husks (RHs by precarbonizing RHs and activating with KOH. The morphology, structure, and specific surface area were investigated. The nanoporous carbon has the average pore size of 2.2 nm and high specific area of 2523.4 m2 g−1. The specific capacitance of the nanoporous carbon is calculated to be 250 F g−1 at the current density of 1 A g−1 and remains 80% for 198 F g−1 at the current density of 20 A g−1. The nanoporous carbon electrode exhibits long-term cycle life and could keep stable capacitance till 10,000 cycles. The consistently high specific capacitance, rate capacity, and long-term cycle life ability makes it a potential candidate as electrode material for supercapacitor.

  20. Isolation and Characterization of Microcrystalline Cellulose (MCC from Rice Husk (RH

    Ahmad Zuliahani


    Full Text Available Microcrystalline cellulose (MCC was extracted from local agricultural residues, rice husk (RH. RH undergone alkaline, bleaching and acid hydrolysis treatments. Nitric acid was used in the hydrolysis process as a potential acid to replace strong acids such as hydrochloric and sulphuric acids. Hydrolysis of RH was carried out by using different molarity of nitric and hydrochloric acids (control. The properties of MCC obtained such as % yield, crystallinity index (CrI and functional group present were studied. % yield shown a comparable result regardless of different acid used. Whilst Fourier transform infrared (FTIR spectroscopy showed the progressive removal of non-cellulosic constituents. X-ray diffraction (XRD analysis revealed that the crystallinity increased with successive treatments regardless different molarity and acids used. The results showed potential of nitric acid to be used in MCC isolation process.

  1. Physical and thermochemical characterization of rice husk char as a potential biomass energy source

    Maiti, S.; Dey, S.; Purakayastha, S.; Ghosh, B. [Jadavpur Univ., Kolkata (India). School of Energy Studies


    The fixed bed pyrolysis of rice husk was studied under conventional conditions with the aim of determining the characteristics of the charcoal formed for its applicability as a solid fuel. Thermoanalytic methods were used to determine the kinetic parameters of its combustion. Palletisation using different binders and techniques to improve the time of sustained combustion of the char pallets were investigated. The optimum temperature for carbonization to obtain a char having moderately high heating value was found as 400 {sup o}C. For the active char combustion zone, the order of reaction was nearly 1, the activation energy 73.403 kJ/mol and the pre-exponential factor 4.97 x 10{sup 4} min{sup -1}. Addition of starch as a binder and 10% ferrous sulphate heptahydrate or sodium hypophosphite as an additive enhanced the ignitibility of the char pallets. (author)

  2. Synthesis and characterization of geopolymer from bottom ash and rice husk ash

    Anggarini, Ufafa; Sukmana, Ndaru C.


    All Geopolymer (GP) has been synthesized from bottom ash and rice husk ash. This research aims to determine the effect of Si/Al ratio on geopolymer synthesis. Geopolymer was synthesized with various Si/Al ratio of 2, 3 and 4. The characterization result using XRD and SEM indicated that by using a different ratio of Si/A, it will produce geopolymer with varied structure and morphology. Diffractogram result shows that polymerization has been done for all samples (GP2, GP3, Gp4) with the presence of hump peak at 2θ = 27-35°. In GP4, no peak at 2θ = 18° indicating sodalite phase forming. Besides that, the morphology of geopolymer with a varied ratio of Si/Al shows that higher ratio will produce geopolymer with higher particle size. The highest compressive strength of geopolymer was obtained at a ratio of Si/Al = 4, with a maximum load of 12866 kgf.

  3. Utilizing Rice Husk Briquettes in Firing Crucible Furnace for Low Temperature Melting Metals in Nigeria

    N. A. Musa


    Full Text Available The search for alternative fuels for firing crucible furnace for low temperature melting metals has become mandatory, as a result of the pollution problem associated with the use of fossil fuels, the expense of electricity and also deforestation as a result of the use of charcoal. An agricultural waste, rice husk, in briquette form was used as an alternative fuel to fire crucible furnace to melt lead, zinc and aluminium. Results showed that lead and zinc melted and reached their pouring temperatures of 3840C and 5300C in 70 minutes and 75 minutes respectively. Aluminium was raised to a maximum temperature of 5200C in 75 and 100 minutes.The average concentration of the pollutants (CO, SO2and NOX were found to be below the tolerance limit and that of TSP (Total Suspended Particulates was found to be within the tolerance limit stipulated by Federal Environmental Protection Agency (FEPA in Nigeria.

  4. Physical and thermochemical characterization of rice husk char as a potential biomass energy source.

    Maiti, S; Dey, S; Purakayastha, S; Ghosh, B


    The fixed bed pyrolysis of rice husk was studied under conventional conditions with the aim of determining the characteristics of the charcoal formed for its applicability as a solid fuel. Thermoanalytic methods were used to determine the kinetic parameters of its combustion. Palletisation using different binders and techniques to improve the time of sustained combustion of the char pallets were investigated. The optimum temperature for carbonization to obtain a char having moderately high heating value was found as 400 degrees C. For the active char combustion zone, the order of reaction was nearly 1, the activation energy 73.403 kJ/mol and the pre-exponential factor 4.97 x 10(4)min(-1). Addition of starch as a binder and 10% ferrous sulphate heptahydrate or sodium hypophosphite as an additive enhanced the ignitibility of the char pallets.

  5. Impact strength and abrasion resistance of high strength concrete with rice husk ash and rubber tires

    M. B. Barbosa

    Full Text Available The paper discusses the application of High Strength Concrete (HSC technology for concrete production with the incorporation of Rice Husk Ash (RHA residues by replacing a bulk of the material caking and rubber tires with partial aggregate volume, assessing their influence on the mechanical properties and durability. For concrete with RHA and rubber, it was possible to reduce the brittleness by increasing the energy absorbing capacity. With respect to abrasion, the RHA and rubber concretes showed lower mass loss than the concrete without residues, indicating that this material is attractive to be used in paving. It is thus hoped that these residues may represent a technological and ecological alternative for the production of concrete in construction works.

  6. Biodiesel production from waste cooking oil using a heterogeneous catalyst from pyrolyzed rice husk.

    Li, Ming; Zheng, Yan; Chen, Yixin; Zhu, Xifeng


    A solid acid catalyst was prepared by sulfonating pyrolyzed rice husk with concentrated sulfuric acid, and the physical and chemical properties of the catalyst were characterized in detail. The catalyst was then used to simultaneously catalyze esterification and transesterification to produce biodiesel from waste cooking oil (WCO). In the presence of the as-prepared catalyst, the free fatty acid (FFA) conversion reached 98.17% after 3h, and the fatty acid methyl ester (FAME) yield reached 87.57% after 15 h. By contrast, the typical solid acid catalyst Amberlyst-15 obtained only 95.25% and 45.17% FFA conversion and FAME yield, respectively. Thus, the prepared catalyst had a high catalytic activity for simultaneous esterification and transesterification. In addition, the catalyst had excellent stability, thereby having potential use as a heterogeneous catalyst for biodiesel production from WCO with a high FFA content. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Preliminary Study on The Potential of Hybrid Rice Husk with Kapok Fiber and Hybrid Rice Husk with Coconut Fiber as Landfill Liner Material

    Nur Azwa Muhamad Bashar


    Full Text Available Abundance of agricultural waste in Malaysia namely rice husk (RH, kapok fiber (KF and coconut fiber (CF has been increasing over the years. This cause disposal problem and air pollution problem from burning activity. In line with the Malaysian Government Policy on the application of green technology concept through the 5R's practice, this agricultural waste has a potential to be commercialized as material for landfill liner. A factor that governs the workability of landfill liner materials is the permeability should be less than 1x10-9 m/s. Therefore, a low permeability material needs to be installed to minimise the environmental impact on the leachate intrusion into groundwater. A series of standard tests to find environmental and geotechnical properties such as atterberg limit test (liquid limit, plastic limit, compaction test, permeability test (falling head method, leachate characteristics and heavy metal test were conducted at various ratio of hybrid materials (KC:RH and KC: CF in the ratio of 1:1 and 1:2 respectively. Experimental results confirmed that the hydraulic conductivity of the mixture of KC:RH:KF in the ratio of 1:1:1 is 7.29 x 10-11 m/s was less than 10-9 m/s, satisfying the requirement for landfill liner materials. Heavy metal testing showed that this hybrid material (RH:KF and RH:CF for ratio 1:2 were able to reduce at least 50 % of the leachate contaminants. The proposed hybrid materials (RH:KF and RH:CF is a green material for the landfill (as it can improve heavy metal adsorption, increase the workability of the landfill by improving the conductivity of the conventional liners, minimizing manpower on site (no need expertise for installation and reduction in cost (in terms of the use of waste materials.


    husk To carry out the study, the researcher used risk husk, cement, waste paper and ... treatment. The samples produced were tested for water absorption, water ... I conventional building materials, efforts have been directed towards the local ...

  9. Optimization of high filler loading on tensile properties of recycled HDPE/PET blends filled with rice husk

    Chen, Ruey Shan; Ahmad, Sahrim; Ghani, Mohd Hafizuddin Ab; Salleh, Mohd Nazry


    Biocomposites of recycled high density polyethylene / recycled polyethylene terephthalate (rHDPE/rPET) blend incorporated with rice husk flour (RHF) were prepared using a corotating twin screw extruder. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to improve the fibre-matrix interface adhesion. The effect of high filler loadings (50-90 wt%) on morphology and tensile properties of compatibilized rHDPE/rPET blend was investigated. The results of our study shown that composite with 70 wt% exhibited the highest tensile strength and Young's modulus, which are 22 MPa and 1752 MPa, respectively. The elongation at break decreased with increasing percentage of RHF. SEM micrograph confirmed fillers dispersion, morphological interaction and enhanced interfacial bonding between recycled polymer blends and rice husk. It can be concluded that the optimum RHF content is 70 wt% with maximum tensile strength.

  10. Electrostatic separation of mineral and vegetal powders with a custom built corona separator: application to biorefinery of rice husk

    Rajaonarivony Rova Karine


    Full Text Available In a dry biorefinery scheme, the separation of plant materials into powders rich in the constituents of interest is a crucial step. In recent years, electrostatic separation of agri-resources has sparked a growing interest for its potentialities, but optimization efforts remain to be done especially in case of fine powders. In this study a custom-designed corona-electrostatic separator has been built and its usage for the separation of mineral (ash from rice husk and vegetal powders (cellulose fibers with different particle size distributions has been studied. First, the powders have been characterized by their electric charge decay curves and their behaviour on the separator was studied. At a second time, separation tests have been carried out with blends of these two powders, and with native, finely ground, rice husk powder (constituted of both mineral and vegetal particles. In each case, the efficiency of the process was evaluated.

  11. Electrostatic separation of mineral and vegetal powders with a custom built corona separator: application to biorefinery of rice husk

    Rajaonarivony, Rova Karine; Rouau, Xavier; Dascalescu, Lucien; Mayer-Laigle, Claire


    In a dry biorefinery scheme, the separation of plant materials into powders rich in the constituents of interest is a crucial step. In recent years, electrostatic separation of agri-resources has sparked a growing interest for its potentialities, but optimization efforts remain to be done especially in case of fine powders. In this study a custom-designed corona-electrostatic separator has been built and its usage for the separation of mineral (ash from rice husk) and vegetal powders (cellulose fibers) with different particle size distributions has been studied. First, the powders have been characterized by their electric charge decay curves and their behaviour on the separator was studied. At a second time, separation tests have been carried out with blends of these two powders, and with native, finely ground, rice husk powder (constituted of both mineral and vegetal particles). In each case, the efficiency of the process was evaluated.

  12. Characterization and use of in natura and calcined rice husks for biosorption of heavy metals ions from aqueous effluents

    M. G. A. Vieira


    Full Text Available Heavy metal removal by adsorption using rice husks as a bioadsorbent was evaluated as an alternative for wastewater treatment. Batch equilibrium experiments and kinetic sorption studies were performed using monocomponent solutions of Ni(II, Cd(II, Zn(II, Pb(II and Cu(II in surface samples of in natura(RH and calcined rice husks (RHA. RHA showed higher potential for removing lead and copper. Experimental data for adsorption isotherms of lead and copper were adjusted by Langmuir, Freundlich and Dubinin-Radushkevick (D-R models, being better represented by the Langmuir model. The calcination of RH increased its surface area, improving its adsorption properties. From a morphological analysis obtained by SEM and diffraction patterns (XRD, a longitudinal fibrous and amorphous structure was observed for RH. TGA resultsindicated a total mass loss of around 60% for RH and 24.5% for RHA.

  13. Comparison of high temperature chars of wheat straw and rice husk with respect to chemistry, morphology and reactivity

    Trubetskaya, Anna; Jensen, Peter Arendt; Jensen, Anker Degn


    Fast pyrolysis of wheat straw and rice husk was carried out in an entrained flow reactor at hightemperatures(1000e1500) C. The collected char was analyzed using X-ray diffractometry, N2-adsorption,scanning electron microscopy, particle size analysis with CAMSIZER XT, 29Si and 13C solid......-statenuclear magnetic resonance spectroscopy and thermogravimetric analysis to investigate the effect ofinorganic matter on the char morphology and oxygen reactivity. The silicon compounds were dispersedthroughout the turbostratic structure of rice husk char in an amorphous phase with a low meltingtemperature (z730 C......), which led to the formation of a glassy char shell, resulting in a preserved particlesize and shape of chars. The high alkali content in the wheat straw resulted in higher char reactivity,whereas the lower silicon content caused variations in the char shape from cylindrical to near...

  14. The Predisposition of Iraqi Rice Husk to Remove Heavy Metals from Aqueous Solutions and Capitalized from Waste Residue

    Mohammed Nsaif; Firas Saeed


    This study is deal with study the potential of Iraqi Rice Husk (IRH) on the removal of three heavy metals pollutant which were (Mg, Mn and Mo) ions from industrial wastewater using different design parameters by adsorption process. Results show that the removal efficiency were (93.95, 97.18 and 95.26) % for heavy metal (Mg, Mn and Mo) respectively from aquatic solution decreased with increasing of initial concentration and flow rate while the removal efficiency increased with increasing absor...

  15. Partial oxidation of methane to methanol over catalyst ZSM-5 from coal fly ash and rice husk ash

    Mirda Yanti Fusia


    Full Text Available Methane is one of the greenhouse gases that can be converted into liquid fuels such as methanol to retain most of the energy of methane and produce a cleaner environment. The conversion of methane to methanol using ZMS-5 represents a breakthrough in the utilization of methane. However, material sources for zeolite synthesis as catalyst usually are pro-analysis grade materials, which are expensive. Therefore, in this research, coal fly ash and rice husk ash were used as raw materials for mesoporous ZSM-5 zeolite synthesis. First, coal fly ash and rice husk were subjected to pre-treatment to extract silicate (SiO44− and aluminate (AlO45− and impurities separation. The ZSM-5 zeolite was synthesized through hydrothermal treatment using two types of templates. After ZSM-5 was synthesized, it was modified with Cobalt through impregnation method. The catalytic activity of both ZSM-5 and Co/ZSM-5 zeolites as heterogeneous catalysts in partial oxidation of methane were preliminary tested and compared with that commercial one. The result showed that the zeolite catalyst ZSM-5 from fly ash coal and rice husk ash has the potential to be used as catalysts in the partial oxidation of methane to methanol.

  16. The Phase-Formation Behavior of Composite Ceramic Powders Synthesized by Utilizing Rice Husk Ash from the Biomass Cogeneration Plant

    Wenjie Yuan


    Full Text Available The development and utilization of biomass as a vital source of renewable energy were stimulated in order to reduce the global dependency on fossil fuels. A lot of rice husk ashes (RHA were generated as the waste after the rice husk as the main fuel was burnt in the biomass cogeneration plant. The phase-formation behavior of composite ceramic powders synthesized by using rice husk ash from the biomass cogeneration plant at the different carbon ratios and temperatures was investigated. The sequence of phase formation with the calcining temperatures ranging from 1773 K to 1853 K was followed by O′-Sialon→SiC + Si3N4→SiC in samples with C/SiO2  =  1 : 1–4 : 1. Ca-α-Sialon formed in samples with C/SiO2  =  5 : 1 and 6 : 1. The results highlighted that series of reactions happening sensitively depended on C/SiO2 and the temperature and demonstrated that the carbothermal nitridation provided an alternative for converting RHA waste into composite ceramic powders.

  17. Cementing Material From Rice Husk-Broken Bricks-Spent Bleaching Earth-Dried Calcium Carbide Residue

    Muthengia Jackson Washira


    Full Text Available A cementious material, coded CSBR (Carbide residue Spent bleaching earth Broken bricks and Rice husks, was made from dried calcium carbide residue (DCCR and an incinerated mix of rice husks (RH, broken bricks (BB and spent bleaching earth (SBE. Another material, coded SBR (Spent bleaching earth Broken bricks and Rice husk ash, was made from mixing separately incinerated RH, SBE and ground BB in the same ash ratio as in CSBR. When CSBR was inter-ground with Ordinary Portland Cement (OPC, it showed a continued decrease in Ca(OH2 in the hydrating cement as a function of curing time and replacement levels of the cement. Up to 45 % replacement of the OPC by CSBR produced a Portland pozzolana cement (PPC material that passed the relevant Kenyan Standard. Incorporation of the CSBR in OPC reduces the resultant calcium hydroxide from hydrating Portland cement. The use of the waste materials in production of cementitious material would rid the environment of wastes and lead to production of low cost cementitious material.

  18. Utilization of maize cob biochar and rice husk charcoal as soil amendments for improving acid soil fertility and productivity



    Full Text Available The decline in soil fertility in agricultural land is a major problem that causes a decrease in the production of food crops. One of the causes of the decline in soil fertility is declining soil pH that caused the decline in the availability of nutrients in the soil. This study aimed to assess the influence of alternative liming materials derived from maize cob biochar and rice husk charcoal compared to conventional lime to improve soil pH, soil nutrient availability and maize production. The experiment used a factorial complete randomized design which consisting of two factors. The first factor is the type of soil amendment which consists of three levels (calcite lime, rice husk charcoal and cob maize biochar. The second factor is the application rates of the soil amendment consisted of three levels (3, 6 and 9 t/ha and one control treatment (without soil amendment. The results of this study showed that the application of various soil amendment increased soil pH, which the pH increase of the lime application was relatively more stable over time compared to biochar and husk charcoal. The average of the soil pH increased for each soil amendment by 23% (lime, 20% (rice husk charcoal and 23% (biochar as compared with control. The increase in soil pH can increase the availability of soil N, P and K. The greatest influence of soil pH on nutrient availability was shown by the relationship between soil pH and K nutrient availability with R2 = 0.712, while for the N by R2 = 0.462 and for the P by R2 = 0.245. The relationship between the availability of N and maize yield showed a linear equation. While the relationship between the availability of P and K with the maize yield showed a quadratic equation. The highest maize yield was found in the application of biochar and rice husk charcoal with a dose of 6-9 t/ha. The results of this study suggested that biochar and husk charcoal could be used as an alternative liming material in improving acid soil

  19. Adsorption and detection of some phenolic compounds by rice husk ash of Kenyan origin.

    Mbui, Damaris N; Shiundu, Paul M; Ndonye, Rachel M; Kamau, Geoffrey N


    Rice husk ash (RHA) obtained from a rice mill in Kenya has been used as an inexpensive and effective adsorbent (and reagent) for the removal (and detection) of some phenolic compounds in water. The abundantly available rice mill waste was used in dual laboratory-scale batch experiments to evaluate its potential in: (i) the removal of phenol, 1,3-dihydroxybenzene (resorcinol) and 2-chlorophenol from water; and (ii) the detection of 1,2-dihydroxybenzene (pyrocatechol) and 1,2,3-trihydroxybenzene (pyrogallol) present in an aqueous medium. The studies were conducted using synthetic water with different initial concentrations of the phenolic compounds. The effects of different operating conditions (such as contact time, concentration of the phenolic compounds, adsorbent quantity, temperature, and pH) were assessed by evaluating the phenolic compound removal efficiency as well as the extent of their color formation reactions (where applicable). RHA exhibits reasonable adsorption capacity for the phenolic compounds and follows both Langmuir and Freundlich isotherm models. Adsorption capacities of 1.53 x 10(-4), 8.07 x 10(-5), and 1.63 x 10(-6) mol g(-1) were determined for phenol, resorcinol and 2-chlorophenol, respectively. Nearly 100% adsorption of the phenolic compounds was possible and this depended on the weight of RHA employed. For the detection experiments, pyrocatechol and pyrogallol present in water formed coloured complexes with RHA, with the rate of colour formation increasing with temperature, weight of RHA, concentration of the phenolic compounds and sonication. This study has proven that RHA is a useful agricultural waste product for the removal and detection of some phenolic compounds.

  20. Use of the rice husk as an alternative substrate for growing media on green walls drip irrigation

    Andrey Rivas-Sánchez, Yair; Fátima Moreno-Pérez, María; Roldán Cañas, José


    In the last years, we have been looking for alternatives to traditional growing mediums for green walls. Commercially available systems for green walls are commonly made with Sphagnum, rock wool or polymers that are unsustainable materials. In the design of the green wall, local components such as agricultural by-products should be considered more often. The objective of this research is to use alternative materials available in Andalusia that are suitable for use as a growing medium in green walls, using organic residues generated by agriculture as in this case the rice husk, compared to conventional and used materials as a growing media in green walls such as coconut fiber and rock wool. The physical-chemical characteristics of the water were analyzed through the collection of excess irrigation water, after passing through the prototypes of green walls, installed in the Rabanales Campus of the University of Córdoba between April and July 2016 and thus observe the feasibility of using rice husk as an alternative material. The 16 mm diameter irrigation pipes are at the top and middle of each module, with 12 adjustable drippers of 4 l / h for each module, 72 drippers in the whole experimental green wall prototype installed at every 15 centimeters of tube. Two different species of plant material (Lampranthus spectabilis) and (Lavandula stoechas), were selected, taking into account the solar exposition of the place of establishment of the prototype of the green wall and the easy acquisition of these plants in the region. Water samples were collected every day twice a day for 10 weeks of the experiment, taking a sample of the surplus runoff water from six green wall prototypes.PH 40 - pH - conductivity - TDS - temperature, CRISON. Differences in pH, electrical conductivity, turbidity and total solids of the treatments were examined by ANOVA with the test of normality and homogeneity of variances. It was observed that the substrates used in the prototypes of the

  1. Microbial Activity and Silica Degradation in Rice Straw

    Kim, Esther Jin-kyung

    Abundantly available agricultural residues like rice straw have the potential to be feedstocks for bioethanol production. Developing optimized conditions for rice straw deconstruction is a key step toward utilizing the biomass to its full potential. One challenge associated with conversion of rice straw to bioenergy is its high silica content as high silica erodes machinery. Another obstacle is the availability of enzymes that hydrolyze polymers in rice straw under industrially relevant conditions. Microbial communities that colonize compost may be a source of enzymes for bioconversion of lignocellulose to products because composting systems operate under thermophilic and high solids conditions that have been shown to be commercially relevant. Compost microbial communities enriched on rice straw could provide insight into a more targeted source of enzymes for the breakdown of rice straw polysaccharides and silica. Because rice straw is low in nitrogen it is important to understand the impact of nitrogen concentrations on the production of enzyme activity by the microbial community. This study aims to address this issue by developing a method to measure microbial silica-degrading activity and measure the effect of nitrogen amendment to rice straw on microbial activity and extracted enzyme activity during a high-solids, thermophilic incubation. An assay was developed to measure silica-degrading enzyme or silicase activity. This process included identifying methods of enzyme extraction from rice straw, identifying a model substrate for the assay, and optimizing measurement techniques. Rice straw incubations were conducted with five different levels of nitrogen added to the biomass. Microbial activity was measured by respiration and enzyme activity. A microbial community analysis was performed to understand the shift in community structure with different treatments. With increased levels of nitrogen, respiration and cellulose and hemicellulose degrading activity

  2. Effects of rice husks and their chars from hydrothermal carbonization on the germination rate and root length of Lepidium sativum

    Kern, Jürgen; Mukhina, Irina; Dicke, Christiane; Lanza, Giacomo; Kalderis, Dimitrios


    Currently, char substrates gain a lot of interest, since they are being discussed as a component in growing media, which may become one option for the replacement of peat. Among different thermal conversion processes of biomass hydrothermal carbonization (HTC) has been found to produce chars with similar acidic pH values like peat. The question however is, if these hydrochars, which may contain toxic phenolic compounds are suitable to be introduced as a new substitute for peat in horticulture. In this study rice husk were hydrothermally carbonized at 200° C for 6 hours, yielding in hydrochars containing organic contaminants such as phenols and furfurals, which may affect plants and soil organisms. We investigated potential toxic effects on the germination rate and the root length of cress salad (Lepidium sativum) in four fractions: i) soil control, ii) raw rice husk + soil, iii) unwashed rice char + soil and iv) acetone/water washed rice char + soil. It could be shown that phenols and furfurals, which were removed from the hydrochar after washing by 80 to 96% did not affect the germination rate and the root length of the cress plants. The lowest germination rate and root length were found in the soil control, the highest in the non-washed hydrochar treatment, indicating a fertilization effect and growth stimulation of cress salad by hydrochar. If this result can be confirmed for other target and non-target organisms in future studies, a new strategy for the production of growing media may be developed.

  3. Pollutant emission characteristics of rice husk combustion in a vortexing fluidized bed incinerator

    Feng Duan; Chiensong Chyang; Yucheng Chin; Jim Tso


    Rice husk with high volatile content was burned in a pilot scale vortexing fiuidized bed incinerator.The fluidized bed incinerator was constructed of 6 mm stainless steel with 0.45 m in diameter and 5 m in height.The emission characteristics of CO,NO,and SO2 were studied.The effects of operating parameters,such as primary air flow rate,secondary air flow rate,and excess air ratio on the pollutant emissions were also investigated.The results show that a large proportion of combustion occurs at the bed surface and the freeboard zone.The SO2 concentration in the flue gas decreases with increasing excess air ratio,while the NOx concentration shows reverse trend.The flow rate of secondary air has a significant impact on the CO emission.For a fixed primary air flowrate,CO emission decreases with the secondary air flowrate.For a fixed excess air ratio,CO emission decreases with the ratio of secondary to primary air flow.The minimum CO emission of 72 ppm is attained at the operating condition of 40% excess air ratio and 0.6 partition air ratio.The NOx and SO2 concentrations in the flue gas at this condition are 159 and 36 ppm,which conform to the EPA regulation of Taiwan.

  4. Rice Husk Supported Catalysts for Degradation of Chlorobenzenes in Capillary Microreactor

    Abdulelah Thabet


    Full Text Available Chlorinated organic pollutants are persistent, toxic, and ubiquitously distributed environmental contaminants. These compounds are highly bioaccumulative and adversely affect the ozone layer in the atmosphere. As such, their widespread usage is a major cause of environmental and health concern. Therefore, it is important to detoxify such compounds by environment friendly methods. In this work, rice husk supported platinum (RHA-Pt and titanium (RHA-Ti catalysts were used, for the first time, to investigate the detoxification of chlorobenzenes in a glass capillary microreactor. High potential (in kV range was applied to a reaction mixture containing buffer solution in the presence of catalyst. Due to high potential, hydroxyl and hydrogen radicals were produced, and the reaction was monitored by gas chromatography-mass spectrometry. The main advantage of this capillary reactor is the in situ generation of hydrogen for the detoxification of chlorobenzene. Various experimental conditions influencing detoxification were optimized. Reaction performance of capillary microreactor was compared with conventional catalysis. Only 20 min is sufficient to completely detoxify chlorobenzene in capillary microreactor compared to 24 h reaction time in conventional catalytic method. The capillary microreactor is simple, easy to use, and suitable for the detoxification of a wide range of chlorinated organic pollutants.

  5. Biosorption of model pollutants in liquid phase on raw and modified rice husks

    Toniazzo, L.; Fierro, V.; Braghiroli, F.; Amaral, G.; Celzard, A.


    We studied the application of rice husk (RH) as a biosorbent and we demonstrated that it can be employed for the treatment of dyeing wastewater streams. RH was obtained from Nile Delta (Egypt) and it was used as received, or after a chemical treatment using HNO3 or NaOH, or after conversion into activated carbon (RH-AC) using H3PO4 as activating agent. A commercial activated carbon GAC 830 provided by NORIT was also tested for comparison purposes. These materials were evaluated by adsorption of methylene blue (MB) with an initial concentration of 20 ppm in an aqueous solution at 30°C. The results showed that alkali-treated and RH-AC were the best sorbents. They got a nearly complete MB removal from water and they had better performance than GAC 830. Therefore, the use of RH for pollutant removal makes this method an environment-friendly option and an economically feasible alternative to treat industrial effluents.

  6. Modeling and Optimization of Compressive Strength of Hollow Sandcrete Block with Rice Husk Ash Admixture


    Full Text Available The paper presents the report of an investigation into the model development and optimization of the compressive strength of 55/45 to 70/30 cement/Rice Husk Ash (RHA in hollow sandcrete block. The low cost and local availability potential of RHA, a pozzolanic material gasps for exploitation. The study applies the Scheffe\\'s optimization approach to obtain a mathematical model of the form f(xi1 ,xi2 ,xi3 xi4 , where x are proportions of the concrete components, viz: cement, RHA, sand and water. Scheffe\\'s i experimental design techniques are followed to mould various hollow block samples measuring 450mm x 225mm x 150mm and tested for 28 days strength. The task involved experimentation and design, applying the second order polynomial characterization process of the simplex lattice method. The model adequacy is checked using the control factors. Finally, a software is prepared to handle the design computation process to take the desired property of the mix, and generate the optimal mix ratios. Reversibly, any mix ratios can be desired and the attainable strength obtained.

  7. The Effect of Various Acids on Properties of Microcrystalline Cellulose (MCC) Extracted from Rice Husk (RH)

    Nur Hanani, A. S.; Zuliahani, A.; Nawawi, W. I.; Razif, N.; Rozyanty, A. R.


    Microcrystalline cellulose (MCC) was successfully extracted from rice husk (RH) via acid hydrolysis process using nitric acid (HNO3) in comparison with sulphuric acid (H2SO4) and hydrochloric acid (HCl). MCC-RH extracted using HNO3 produced the highest percentage yield at 83.5% as compared to H2SO4 and HCl at 80.6% and 81.8% respectively. Analysis of Fourier Transform Infrared (FTIR) spectroscopy affirmed the successive elimination of non-cellulosic material from RH cellulose resulting highly purified MCC-RH. X-ray Diffraction (XRD) analysis showed MCC-RH treated with HCl gives the highest crystallinity index value of 54.2% while HNO3 and H2SO4 produced comparable results of 52.4% and 49.7% respectively. The results indicate successive extraction of MCC-RH using HNO3 that has great potential to replace strong acid such as H2SO4 and HCl in acid hydrolysis.

  8. Removal of elemental mercury by iodine-modified rice husk ash sorbents

    Pengfei Zhao; Xin Guo; Chuguang Zheng


    Iodine-modified calcium-based rice husk ash sorbents (I2/CaO/RHA) were synthesized and characterized by X-ray diffraction,X-ray fluorescence,and N2 isotherm adsorpdon/desorption.Adsorption experiments of vapor-phase elemental mercury (Hg0) were performed in a laboratory-scale fixed-bed reactor.I2/CaO/RHA performances on Hg0 adsorption were compared with those of modified Cabased fly ash sorbents (I2/CaO/FA) and modified fly ash sorbents (I2/FA).Effects of oxidant loading,supports,pore size distribution,iodine impregnation modes,and temperature were investigated as well to understand the mechanism in capturing Hg0.The modified sorbents exhibited reasonable efficiency for Hg0 removal under simulated flue gas.The surface area,pore size distribution,and iodine impregnation modes of the sorbents did not produce a strong effect on Hg0 capture efficiency,while fair correlation was observed between Hg0 uptake capacity and iodine concentration.Therefore,the content of I2 impregnated on the sorbents was identified as the most important factor influencing the capacity of these sorbents for Hg0 uptake.Increasing temperature in the range of 80-140℃ caused a rise in Hg0 removal.A reaction mechanism that may explain the experimental results was presumed based on the characterizations and adsorption study.

  9. Strength of Ternary Blended Cement Sandcrete Containing Afikpo Rice Husk Ash and Saw Dust Ash

    L. O. Ettu


    Full Text Available This work investigated the compressive strength of ternary blended cement sandcrete containing Afikpo rice husk ash (RHA and sawdust ash (SDA. 105 sandcrete cubes of 150mm x 150mm x 150mm were produced with OPC-RHA binary blended cement, 105 with OPC-SDA binary blended cement, and 105 with OPC-RHA-SDA ternary blended cement, each at percentage OPC replacement with pozzolan of 5%, 10%, 15%, 20%, and 25%. Three cubes for each percentage replacement of OPC with pozzolan and the control were tested for saturated surface dry bulk density and crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, and 90 days of curing. The 90-day strengths obtained from ternary blending of OPC with equal proportions of RHA and SDA were 11.80N/mm2for 5% replacement, 11.20N/mm2for 10% replacement, 10.60N/mm2for 15% replacement, 10.00N/mm2for 20% replacement, and 9.10N/mm2for 25% replacement, while that of the control was 10.90N/mm2. This suggests that very high sandcrete strength values could be obtained with OPCRHA-SDA ternary blended cement with richer mixes, high quality control, and longer days of hydration. Thus, OPC-RHA-SDA ternary blended cement sandcrete could be used for various civil engineering and building works, especially where early strength is not a major requirement.

  10. Synergic Effect of Wheat Straw Ash and Rice-Husk Ash on Strength Properties of Mortar

    Goyal, Ajay; Kunio, Hattori; Ogata, Hidehiko; Garg, Monika; Anwar, A. M.; Ashraf, M.; Mandula

    Pozzolan materials obtained from various sources; when used as partial replacement for Portland cement in cement based applications play an important role not only towards sustainable development but in reducing the construction costs as well. Present study was conducted to investigate the synergic effect of Rice-Husk Ash (RHA) and Wheat Straw Ash (WSA) on the strength properties of ash substituted mortar. Ash materials were obtained after burning the wastes at 600°C for 5 h at a control rate of 2°C min. Two binary blends of mortar substituting 15% cement with WSA and RHA and three combinations of ternary blend with (10+5)%, (5+10)% and (7.5+7.5)% mix ratios of WSA and RHA, together with a control specimen were subjected to destructive (compressive and flexural strength) as well as non-destructive (ultrasonic pulse velocity) tests till 180 days of curing. Ternary blend with (7.5 + 7.5)% combination of WSA and RHA showed better strength results than control and other blends and proved to be the optimum combination for achieving maximum synergic effect.

  11. Synthesis of ZSM-5 zeolite from lignite fly ash and rice husk ash

    Chareonpanich, Metta; Namto, Teerapong; Kongkachuichay, Paisan [Department of Chemical Engineering, Kasetsart University, 50 Paholyothin Rd., Chatuchak, Bangkok 10900 (Thailand); Limtrakul, Jumras [Department of Chemistry, Kasetsart University, Chatuchak, Bangkok 10900 (Thailand)


    The lignite fly ash from the Mae-Moh power plant, Thailand, and rice husk ash were used as raw materials for ZSM-5 zeolite synthesis. Factors affecting the yield of ZSM-5 zeolite synthesized from fly ash, i.e., the SiO{sub 2}/Al{sub 2}O{sub 3} mole ratio, the presence of tetrapropyl ammonium bromide (TPABr, the structure-directing material for ZSM-5 zeolite synthesis), the holding temperature and time, and the initial pressure were investigated. It was found that without TPABr only zeolite P could be synthesized at SiO{sub 2}/Al{sub 2}O{sub 3} mole ratios of 2.8-200. In order to synthesize ZSM-5 zeolite, sodium silicate solution was added to adjust the SiO{sub 2}/Al{sub 2}O{sub 3} mole ratio in raw ash. The yield of ZSM-5 zeolite was as high as 59 wt.% when following conditions were used: SiO{sub 2}/Al{sub 2}O{sub 3} mole ratio, 40; the holding temperature, 210 C; the holding time, 4 h and the initial pressure, 4 bar. The catalytic performance for CO{sub 2} hydrogenation reaction of the ZSM-5 zeolite was preliminary tested and compared with that of commercial one. It was observed that there was no significant difference in the catalytic performance between these two catalysts.

  12. Characteristics and mechanisms of nickel adsorption on biochars produced from wheat straw pellets and rice husk.

    Shen, Zhengtao; Zhang, Yunhui; McMillan, Oliver; Jin, Fei; Al-Tabbaa, Abir


    The adsorption characteristics and mechanisms of Ni(2+) on four-standard biochars produced from wheat straw pellets (WSP550, WSP700) and rice husk (RH550, RH700) at 550 and 700 °C, respectively, were investigated. The kinetic results show that the adsorption of Ni(2+) on the biochars reached an equilibrium within 5 min. The increase of the solid to liquid ratio resulted in an increase of Ni(2+) removal percentage but a decrease of the adsorbed amount of Ni(2+) per weight unit of biochar. The Ni(2+) removal percentage increased with the increasing of initial solution pH values at the range of 2-4, was relatively constant at the pH range of 4-8, and significantly increased to ≥98% at pH 9 and stayed constantly at the pH range of 9-10. The calculated maximum adsorption capacities of Ni(2+) for the biochars follow the order of WSP700 > WSP550 > RH700 > RH550. Both cation exchange capacity and pH of biochar can be a good indicator of the maximum adsorption capacity for Ni(2+) showing a positively linear and exponential relationship, respectively. This study also suggests that a carefully controlled standardised production procedure can make it reliable to compare the adsorption capacities between different biochars and investigate the mechanisms involved.

  13. Impact Resistance Behaviour of Light Weight Rice Husk Concrete with Bamboo Reinforcement

    Che Muda, Zakaria; Beddu, Salmia; Syamsir, Agusril; Sigar Ating, Joshua; Liyana Mohd Kamal, Nur; Nasharuddin Mustapha, Kamal; Thiruchelvam, Sivadass; Usman, Fathoni; Ashraful Alam, Md; Birima, Ahmed H.; Zaroog, O. S.


    This paper investigate the performance of lightweight rice husk concrete (LWRHC) with varied bamboo reinforcement content for the concrete slab of 300mm × 300mm size reinforced with varied slab thickness subjected to low impact projectile test. A self-fabricated drop-weight impact test rig with a steel ball weight of 1.236 kg drop at 0.65 m height has been used in this research work. The main variables for the study is to find the relationship of the impact resistance against the amount of bamboo reinforcement and slab thickness. A linear relationship has been established between first and ultimate crack resistance against bamboo diameters and slab thickness by the experiment. The linear relationship has also been established between the service (first) crack and ultimate crack resistance against the bamboo reinforcement diameter and slab thickness. 5% RH content exhibit better first and ultimate crack resistance up to 1.80 times and up to 1.72 times respectively against 10% RH content.

  14. Use of rice husk for the removal of methylene blue in fixed-bed columns

    Yurany A. Villada-Villada


    Full Text Available This work shows the use of rice husk in the removal of cationic dye methylene blue on continuous system. A factorial design 23 with center points and random distribution was implemented to evaluate the correlation of the experimental factors in the adsorption process. The considered variables were pH, particle size, salt presence, flow rate, dye initial concentration, and bed depth. The samples were analyzed in defined time intervals. The amount of removed dye was quantified by UV spectroscopy - Visible. Adams-Bohart, Thomas and BDST (Bed-depht/service time analysis models were used to predict the breakthrough curves using non-linear regression and establish the characteristic parameters of the process. It was found that the transference of dye toward the adsorbent is favored by a basic pH, a small particle size, low flow rate and dye concentration, and high bed depth. The design of experiments established that the initial dye concentration and the bed depth were the most significant factors. Regarding the models, the Thomas provided the best fit to describe the breakthrough curves in experimental conditions and Adams-Bohart was found suitable for dynamic behavior limited to the initial part. Finally, BDST model exhibited a good correlation and allowed to establish that bed depth is a determinant factor for scaling process.

  15. Modeling and Optimization for Production of Rice Husk Activated Carbon and Adsorption of Phenol

    Y. S. Mohammad


    Full Text Available Modeling of adsorption process establishes mathematical relationship between the interacting process variables and process optimization is important in determining the values of factors for which the response is at maximum. In this paper, response surface methodology was employed for the modeling and optimization of adsorption of phenol onto rice husk activated carbon. Among the action variables considered are activated carbon pretreatment temperature, adsorbent dosage, and initial concentration of phenol, while the response variables are removal efficiency and adsorption capacity. Regression analysis was used to analyze the models developed. The outcome of this research showed that 99.79% and 99.81% of the variations in removal efficiency and adsorption capacity, respectively, are attributed to the three process variables considered, that is, pretreatment temperature, adsorbent dosage, and initial phenol concentration. Therefore, the models can be used to predict the interaction of the process variables. Optimization tests showed that the optimum operating conditions for the adsorption process occurred at initial solute concentration of 40.61 mg/L, pretreatment temperature of 441.46°C, adsorbent dosage 4 g, adsorption capacity of 0.9595 mg/g, and removal efficiency of 97.16%. These optimum operating conditions were experimentally validated.

  16. Strength and durability performance of alkali-activated rice husk ash geopolymer mortar.

    Kim, Yun Yong; Lee, Byung-Jae; Saraswathy, Velu; Kwon, Seung-Jun


    This paper describes the experimental investigation carried out to develop the geopolymer concrete based on alkali-activated rice husk ash (RHA) by sodium hydroxide with sodium silicate. Effect on method of curing and concentration of NaOH on compressive strength as well as the optimum mix proportion of geopolymer mortar was investigated. It is possible to achieve compressive strengths of 31 N/mm(2) and 45 N/mm(2), respectively for the 10 M alkali-activated geopolymer mortar after 7 and 28 days of casting when cured for 24 hours at 60°C. Results indicated that the increase in curing period and concentration of alkali activator increased the compressive strength. Durability studies were carried out in acid and sulfate media such as H2SO4, HCl, Na2SO4, and MgSO4 environments and found that geopolymer concrete showed very less weight loss when compared to steam-cured mortar specimens. In addition, fluorescent optical microscopy and X-ray diffraction (XRD) studies have shown the formation of new peaks and enhanced the polymerization reaction which is responsible for strength development and hence RHA has great potential as a substitute for ordinary Portland cement concrete.




    Full Text Available The present work involves the study of Se(IV adsorption onto rice husk ash (RHA. The adsorbents were coated with the ferric chloride solution for the effective removal of selenium. The physico-chemical characterization of the adsorbents was carried out using standard methods, e.g., proximate analysis, scanning electron microscopy (SEM, fourier transform infrared spectroscopy (FTIR, thermo-gravimetric (TGA and differential thermal analysis (DTA, etc. Batch experiments were carried out to determine the effect of various factors such as adsorbent dose (w, initial pH, contact time (t, and temperature (T on adsorption process. Se(IV adsorption is high at low pH values, and decreased with the rise in initial pH. Temperature study shows that the uptake of Se(IV is more at 293 K within the temperature range studied. The parameters of Pseudo-First order, Pseudo-Second order kinetics, Weber-Morris intra particle kinetics have been determined. Equilibrium isotherms have been analyzed using Langmuir isotherm, Freundlich isotherm and Temkin isotherm. Error analysis has also been done using hybrid fractional error function (HYBRID and Marquardt’s percent standard deviation (MPSD.

  18. Synthesis of adsorbent with zeolite structure from red mud and rice husk ash and its properties

    Quyen, Dinh Thi Ngoc; Loc, Luu Cam; Ha, Huynh Ky Phuong; Nga, Dang Thi Hang; Tri, Nguyen; Van, Nguyen Thi Thuy


    There are many researches in the modification of red mud as adsorbent for treatment of wastewater or waste gases. Yet, most of them have to face up with a thorny problem caused by remaining alkali in red mud. In this study, the material with zeolite structure was synthesized by fusion method using red mud with the remaining alkali and rice husk ash as raw materials. It comprised alkaline fusion followed by hydrothermal treatment with step - change of synthesis temperature. The synthesized materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), BET and CO2 adsorption capacity. The influences on the quality of these materialswere investigated under various calcination temperatures, calcination times and the ratios of raw materials (based on SiO2/Al2O3 ratio). The optimum reaction parameters were determined. The results depicted that the sample treated at 600 °C for 2 hours with the ratio of SiO2/Al2O3 of 1.8 had the best adsorption capacity and total specific surface area compared with the others.

  19. Arsenic and fluoride removal by potato peel and rice husk (PPRH) ash in aqueous environments.

    Bibi, Sadia; Farooqi, Abida; Yasmeen, Azra; Kamran, Muhammad Aqeel; Niazi, Nabeel Khan


    Finding appropriate adsorbent may improve the quality of drinking water in those regions where arsenic (As) and fluoride (F(-)) are present in geological formations. In this study, we evaluated the efficiency of potato peel and rice husk ash (PPRH-ash) derived adsorbent for the removal of arsenic and fluoride from contaminated water. Evaluation was done in batch adsorption experiments and the effect of pH, initial adsorbate concentration, contact time and adsorbent dose were studied. The characterization of adsorbents were done using scanning electron micropcope (SEM) and Fourier transform infrared (FTIR) spectroscopy. Both the Langmuir and Freundlich isotherm models fitted well for F(-) and As sorption process. The maximum adsorption capacity of adsorbent for As and F(-) were 2.17 μg g(-1) and 2.91 mg g(-1) respectively. The optimum As and F(-) removal was observed between pH 7 and 9. The sorption process was well explained with pseudo-second order kinetic model. The As adsorption was not decreased in the presence of carbonate and sulfate. Results from this study demonstrated potential utility of this agricultural biowaste which could be developed into a viable filtration technology for As and F(-) removal in As- and F-contaminated water streams.

  20. Characterization and Stabilisation of Biochars Obtained from Empty Fruit Bunch, Wood, and Rice Husk

    Hamdan Jol


    Full Text Available Agricultural production in Malaysia has been continually growing. Most of the agricultural waste has been discarded or burnt on land; however, these agricultural wastes can serve as a feedstock for biochar production, which contributes an insignificant net amount of carbon dioxide to the atmosphere after soil incorporation. Three kinds of primary biochar were used in this study: empty fruit bunch biochar (EFB, wood biochar (WB, and rice husk biochar (RHB. EFB and WB were produced by slow pyrolysis, whereas RHB was produced by gasification. This study aimed to understand how pyrolysis technologies of native feedstocks impact the chemical characteristics and short-term soil stability of biochar. The kinetic parameters of C-mineralization suggested a tri-phasic C-mineralization process (labile, unstable, and recalcitrant carbon. The estimates indicated the existence of a very labile C-fraction in RHB with a very small decay constant K3. Fourier transform infrared spectroscopy and X-ray diffraction showed the three phases of the biochar, from the microcrystalline C of the labile fraction to the largely amorphous intermediate C of the unstable fraction, and lastly the formation of turbostratic crystallite C in the recalcitrant fraction. It has been concluded that RHB had a higher degree of aromaticity and greater stability, and therefore should be more recalcitrant to biological and chemical degradation.

  1. Effects of pyrolysis temperature on the physicochemical properties of empty fruit bunch and rice husk biochars.

    Claoston, N; Samsuri, A W; Ahmad Husni, M H; Mohd Amran, M S


    Biochar has received great attention recently due to its potential to improve soil fertility and immobilize contaminants as well as serving as a way of carbon sequestration and therefore a possible carbon sink. In this work, a series of biochars were produced from empty fruit bunch (EFB) and rice husk (RH) by slow pyrolysis at different temperatures (350, 500, and 650°C) and their physicochemical properties were analysed. The results indicate that porosity, ash content, electrical conductivity (EC), and pH value of both EFB and RH biochars were increased with temperature; however, yield, cation exchange capacity (CEC), and H, C, and N content were decreased with increasing pyrolysis temperature. The Fourier transform IR spectra were similar for both RH and EFB biochars but the functional groups were more distinct in the EFB biochar spectra. There were reductions in the amount of functional groups as pyrolysis temperature increased especially for the EFB biochar. However, total acidity of the functional groups increased with pyrolysis temperature for both biochars.

  2. Adsorption of sulfur compound utilizing rice husk ash modified with niobium

    Cavalcanti, Rodrigo M.; Pessoa Júnior, Wanison A.G. [Laboratório de Catálise Química e Materiais (CATAMA), Instituto de Ciências Exatas, Universidade Federal do Amazonas (UFAM), Av. Gen. Rodrigo Otávio Jordão Ramos, 6200, 69077-000 Manaus, AM (Brazil); Braga, Valdeilson S. [Laboratório de Catálise, Centro das Ciências Exatas e das Tecnologias, Universidade Federal do Oeste da Bahia, Rua Professor José Seabra de Lemos, 316, Recanto dos Pássaros, 47808-021 Barreira, BA (Brazil); Barros, Ivoneide de C.L., E-mail: [Laboratório de Catálise Química e Materiais (CATAMA), Instituto de Ciências Exatas, Universidade Federal do Amazonas (UFAM), Av. Gen. Rodrigo Otávio Jordão Ramos, 6200, 69077-000 Manaus, AM (Brazil)


    Graphical abstract: - Highlights: • Adsorbents based in RHA modified with niobium were prepared by impregnation. • The impregnation modified the particle size and topology of RHA particles. • The adsorbents were applied in sulfur removal in model liquid fuels. • The larger sulfur removal (>50%) was achieved using RHA with 5 wt.% niobium oxide. • The adsorbent show great selectivity in adsorption experiments. - Abstract: Adsorbents based in rice husk ash (RHA) modified with niobium pentoxide were prepared for impregnation methods and applied in sulfur removal in liquid fuels. The solids were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, nitrogen physisorption and thermal analysis; they show that there was no qualitative change in the amorphous structure of the RHA; however, the method of impregnation could modify the particle size and topology of RHA particles. The larger sulfur removal (>50%) was achieved using RHA with 5 wt.% Nb{sub 2}O{sub 5} at a dosage of 10 g L{sup −1}, after 4 h of contact with the model fuel. The kinetic study of adsorption of thiophene showed that the models of pseudo-second order and intra-particle diffusion best fit the experimental data. The adsorption experiments with the thiophenic derivatives compounds show a large selectivity of the adsorbent.

  3. Evaluation of sulfate resistance of cement mortars containing black rice husk ash.

    Chatveera, B; Lertwattanaruk, P


    In this paper, black rice husk ashes (BRHAs), which are agrowastes from an electricity generating power plant and a rice mill, were ground and used as a partial cement replacement. The durability of mortars under sulfate attack including expansion and compressive strength loss were investigated. For parametric study, BRHA were used as a Portland cement Type 1 replacement at the levels of 0%, 10%, 30%, and 50% by weight of binder. The water-to-binder ratios were 0.55 and 0.65. For the durability of mortar exposed to sulfate attack, 5% sodium sulfate (Na2SO4) and magnesium sulfate (MgSO4) solutions were used. As a result, when increasing the percentage replacement of BRHA, the expansion and compressive strength loss of mortar decreased. At the replacement levels of 30% and 50% of BRHA, the expansion of the mortars was less than those mixed with sulfate-resistant cement. However, the expansion of the mortars exposed to Na2SO4 was more than those exposed to MgSO4. Increasing the replacement level of BRHA tends to reduce the compressive strength loss of mortars exposed to Na2SO4 attack. In contrary, under MgSO4 attack, when increasing the replacement level of BRHA, the compressive strength loss increases from 0% to 50% in comparison to Portland cement mortar. Results show that ground BRHA can be applied as a pozzolanic material to concrete and also improve resistance to sodium sulfate attack, but it can impair resistance to magnesium sulfate attack.

  4. Enhanced ethanol and glucosamine production from rice husk by NAOH pretreatment and fermentation by fungus Mucor hiemalis

    Maryam Omidvar


    Full Text Available Ethanol production from rice husk by simultaneous saccharification and fermentation using Mucor hiemalis was investigated. To reach the maximum ethanol production yield, the most important influencing factors in the pretreatment process, including temperature (0-100°C, NaOH concentration (1-3 M, and the pretreatment time (30-180 min, were optimized using an experimental design by a response surface methodology (RSM. The maximum ethanol production yield of 86.7 % was obtained after fungal cultivation on the husk pretreated with 2.6 M NaOH at 67°C for 150 min. This was higher than the yield of 57.7% obtained using Saccharomyces cerevisiae as control. Furthermore, fermentation using M. hiemalis under the optimum conditions led to the production of a highly valuable fungal biomass, containing 60 g glucosamine (GlcN, 410 g protein, and 160 g fungal oil per each kg of the fungal biomass.

  5. The influence of activating agents on the performance of rice husk-based carbon for sodium lauryl sulfate and chrome (Cr) metal adsorptions

    Arneli; Safitri, Z. F.; Pangestika, A. W.; Fauziah, F.; Wahyuningrum, V. N.; Astuti, Y.


    This research aims to study the influence of activating agents to produce rice husk based-carbon with high adsorption capacity and efficiency for either hazardous organic molecules or heavy metals which are unfriendly for the environment. Firstly, rice husk was burned by pyrolysis at different temperatures to produce rice husk-based carbon. To improve its ability as an adsorbent, carbon was treated with activating agents, namely, H3PO4 and KOH at room and high temperature (420 °C). The performance of carbon was then tested by contacting it with surfactant (SLS). Finally, the surfactant-modified active carbon was applied for chrome metal removal. The result shows that activation of carbon using phosphate acid (H3PO4) was more effective than potassium hydroxide (KOH) conducted at high temperature to adsorb sodium lauryl sulfate (SLS) and chrome metal with the adsorption capacity 1.50 mgg-1 and 0.375 mgg-1, respectively.

  6. Co-Production of Nattokinase and Poly (γ-Glutamic Acid Under Solid-State Fermentation Using Soybean and Rice Husk

    Guangjun Nie


    Full Text Available ABSTRACTThe aim of this work was to study the co-production of nattokinase and poly (γ-glutamic acid by Bacillus subtilis natto with soybean and rice husk under solid-state fermentation (SSF. The results showed that the size of soybean particle and rice husk significantly improved the co-production of nattokinase and poly (γ-glutamic acid, yielding 2503.4 IU/gs and 320 mg/gs, respectively in the improved culture medium composed of 16.7% soybean flour and 13.3% rice husk with 70% water content. The yields increased by approximate 7- and 2-fold factor relative to their original ones. Thus, the co-production of nattokinase and poly (γ-glutamic acid under SSF could be considered as an efficient method to exploit agro-residues for economical production of some higher-value products.

  7. Prediction of Compressive Strength of Self compacting Concrete with Flyash and Rice Husk Ash using Adaptive Neuro-fuzzy Inference System

    S. S, Pathak


    Full Text Available Self-compacting concrete is an innovative concrete that does not require vibration for placing and compaction. It is able to flow under its own weight, completely filling formwork and achieving full compaction even in congested reinforcement without segregation and bleeding. In the present study self compacting concrete mixes were developed using blend of fly ash and rice husk ash. Fresh properties of theses mixes were tested by using standards recommended by EFNARC (European Federation for Specialist Construction Chemicals and Concrete system. Compressive strength at 28 days was obtained for these mixes. This paper presents development of Adaptive Neuro-fuzzy Inference System (ANFIS model for predicting compressive strength of self compacting concrete using fly ash and rice husk ash. The input parameters used for model are cement, fly ash, rice husk ash and water content. Output parameter is compressive strength at 28 days. The results show that the implemented model is good at predicting compressive strength.

  8. Potentiometric stripping analysis of antimony based on carbon paste electrode modified with hexathia crown ether and rice husk

    Gadhari, Nayan S.; Sanghavi, Bankim J. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Srivastava, Ashwini K., E-mail: [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India)


    Highlights: {yields} Potentiometric stripping analysis (PSA) employed for the determination of antimony. {yields} Hexathia-18C6 and rice husk modified carbon paste electrode developed for the analysis. {yields} Lowest detection limit obtained for the determination of Sb(III) using PSA. {yields} Analysis of Sb in pharmaceutical formulations, human hair, blood serum, urine and sea water. {yields} Rice husk used as a modifier for the first time in electrochemistry. - Abstract: An electrochemical method based on potentiometric stripping analysis (PSA) employing a hexathia 18C6 (HT18C6) and rice husk (RH) modified carbon paste electrode (HT18C6-RH-CPE) has been proposed for the subnanomolar determination of antimony. The characterization of the electrode surface has been carried out by means of scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. By employing HT18C6-RH-CPE, a 12-fold enhancement in the PSA signal (dt/dE) was observed as compared to plain carbon paste electrode (PCPE). Under the optimized conditions, dt/dE (s V{sup -1}) was proportional to the Sb(III) concentration in the range of 1.42 x 10{sup -8} to 6.89 x 10{sup -11} M (r = 0.9944) with the detection limit (S/N = 3) of 2.11 x 10{sup -11} M. The practical analytical utilities of the modified electrode were demonstrated by the determination of antimony in pharmaceutical formulations, human hair, sea water, urine and blood serum samples. The prepared modified electrode showed several advantages, such as simple preparation method, high sensitivity, very low detection limit and excellent reproducibility. Moreover, the results obtained for antimony analysis in commercial and real samples using HT18C6-RH-CPE and those obtained by inductively coupled plasma-atomic emission spectrometry (ICP-AES) are in agreement at the 95% confidence level.

  9. Phytoremediation of Gold Mine Tailings Amended with Iron-Coated and Uncoated Rice Husk Ash by Vetiver Grass (Vetiveria zizanioides (Linn.) Nash)

    Tariq, F. S.; Samsuri, A. W.; D. S. Karam; Aris, A. Z.


    This study was undertaken to determine the effects of rice husk ash (RHA) and iron-coated rice husk ash (Fe-RHA) on phytoavailability of As, Cd, Cr, Cu, Mn, Pb, and Zn to vetiver grass grown in gold mine tailings amended with either RHA or Fe-RHA at 0%, 5%, 10%, and 20% (w/w). The results showed that the RHA amended tailings recorded higher concentration of As in the shoot and the root and higher concentration of Cr and Mn in the root compared to the untreated tailings which was used as a con...

  10. Phytoremediation of Gold Mine Tailings Amended with Iron-Coated and Uncoated Rice Husk Ash by Vetiver Grass (Vetiveria zizanioides (Linn.) Nash)

    Tariq, F. S.; Samsuri, A. W.; Karam, D. S.; Aris, A. Z.


    This study was undertaken to determine the effects of rice husk ash (RHA) and iron-coated rice husk ash (Fe-RHA) on phytoavailability of As, Cd, Cr, Cu, Mn, Pb, and Zn to vetiver grass grown in gold mine tailings amended with either RHA or Fe-RHA at 0%, 5%, 10%, and 20% (w/w). The results showed that the RHA amended tailings recorded higher concentration of As in the shoot and the root and higher concentration of Cr and Mn in the root compared to the untreated tailings which was used as a con...

  11. Obtention of charcoal briquettes from rice husks using low compaction pressure; Obtencao de briquetes de carvao vegetal de cascas de arroz utilizando baixa pressao de compactacao

    Morais, Marcia R.; Seye, Omar; Freitas, Katrina T. de; Rodrigues, Monica; Santos, Eyde C.S. dos; Souza, Rubem C.R. [Universidade Federal do Amazonas (CDEAM/UFAM), Manaus, AM (Brazil). Centro de Desenvolvimento Energetico Amazonico


    This work consists of the preparation of briquette from carbonized rice's husks in low pressure. The results demonstrate are necessary a fine granulation of the rice's husks coal to obtainment of briquettes. The ultimate analysis of the briquette did not detect the presence of nitrogen and sulfur, and that prevents the formation and emission of acid gases that can produce corrosion in the equipment and pollute the atmosphere. The performance of the briquette production was superior to 80%. The briquettes present high heating value (HHV) 17,73 MJ/kg and adequate mechanic resistance for the use in gasifier-engine system. (author)


    Norazlina Abu Sari


    Full Text Available Biochar as a new soil amendment has a potential in controlling the fate of trace elements in the soil system. However, the production of biochar from different feedstocks and pyrolysis conditions resulted in variable biochar properties which have an influence on trace elements availability. The experimental works are focused on physical and chemical properties of biochars produced from Empty Fruit Bunch (EFB and Rice Husk (RH as heavy metals adsorbents. The morphology of EFB biochar comprise rigid structure with uniform pores size. The surface area of biochars ranged between 23.22-46.32 m2 g-1, dominated with mesopores. The chemical characterization of biochars revealed high carbon content in EFB biochar compared to RH biochar (54.08 and 7.78%. Both biochars are alkaline in nature (>pH 9 and contain substantial amounts of N, P, K, Ca and Mg. Fourier transform infra-red spectra showed the heterogenic functional groups on EFB biochar surface and domination of silica content in RH biochar. The batch experiment was employed to determine the adsorption capacity of these biochars for As and Cd. The adsorption data were fitted well in Langmuir isotherm with high correlation coefficient (R2>0.9 for As and Cd. The qmax of EFB biochar for As and Cd was higher than RH biochar. The qmax of EFB biochar was 0.4240 and 15.1515 mg g-1 for As and Cd, respectively. In contrast, the qmax of RH biochar for As and Cd was only 0.3522 and 3.1908 mg g-1. The results show that EFB biochar and RH biochar have potentials as good sorbent for As and Cd. Therefore, it can be suggested that the application of these biochars may possibly reduce the trace elements availability in the contaminated soil.

  13. Synthesis and characterization of LTA nanozeolite using barley husk silica: Mercury removal from standard and real solutions

    Azizi, Seyed Naser, E-mail: [Analytical Division, Faculty of Chemistry, University of Mazandaran, P.O. Box: 47416-95447, Babolsar (Iran, Islamic Republic of); Dehnavi, Ahmad Roozbehani, E-mail: [Research Institute of Petroleum Industry (RIPI), Tehran (Iran, Islamic Republic of); Joorabdoozha, Amir [Analytical Division, Faculty of Chemistry, University of Mazandaran, P.O. Box: 47416-95447, Babolsar (Iran, Islamic Republic of)


    Highlights: ► Silica extraction from barley husk with high purity for the synthesis of A nanozeolite. ► Free template A nanozeolite synthesized via new source of silica at low temperature. ► Optimization of SiO{sub 2}/Al{sub 2}O{sub 3}, Na{sub 2}O/SiO{sub 2} ratios, temperature and time of the synthesis. ► Utilizing of synthesized A nanozeolite for mercury removal from aqueous solutions. ► Mercury removal at optimized pH, contact time and adsorbent dose from real solution. - Abstract: In this study, synthesized Lined Type A (LTA) nanozeolite from barley husk silica (BHS) was used for mercury removal from standard and real aqueous solutions. The BHS in amorphous phase with 80% purity was extracted from barley husk ash (BHA), and used effectively as a new source of silica for the synthesis of NaA nanozeolite. The NaA nanocrystal in pure phase has been synthesized at low temperature, without adding any organic additives. The effects of heating time, reaction temperature, SiO{sub 2}/Al{sub 2}O{sub 3}, and Na{sub 2}O/SiO{sub 2} mole ratios on the crystallization of NaA nanozeolite were studied. The adsorption capacity of mercury (II) was studied as a function of pH, contact time, and amount of adsorbent. The crystallization of NaA nanozeolite from BHS was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Brunauer–Emmett–Teller (BET), and FTIR techniques. Moreover, concentration of Hg{sup 2+} ions in the aqueous solutions was analyzed by hydride generation atomic absorption spectroscopy method (HG-AAS). The standard and real samples analysis showed that NaA nanozeolite is capable of Hg{sup 2+} ions removal from the aqueous solutions. Efficiency of mercury (II) adsorption from real solutions onto the nano-sized NaA zeolite was 98%.

  14. Co-combustion performance of coal with rice husks and bamboo

    Kwong, P.C.W.; Chao, C.Y.H.; Wang, J.H.; Cheung, C.W.; Kendall, G. [Hong Kong University of Science & Technology, Kowloon (China). Dept. of Mechanical Engineering


    Biomass has been regarded as an important form of renewable energy due to the reduction of greenhouse gas emission such as carbon dioxide. An experimental study of co-combustion of coal and biomass was performed in a laboratory-scale combustion facility. Rice husks and bamboo were the selected biomass fuels in this study due to their abundance in the Asia-Pacific region. Experimental parameters including the biomass blending ratio in the fuel mixture, relative moisture content and biomass grinding size were investigated. Both energy release data and pollutant emission information were obtained. Due to the decrease in the heating value from adding biomass in the fuel mixture, the combustion temperature and energy output from the co-firing process were reduced compared with coal combustion. On the other hand, gaseous pollutant emissions including carbon monoxide (CO), carbon dioxide (CO{sub 2}), nitrogen oxides (NOx) and sulfur dioxide (SO{sub 2}) were reduced and minimum energy-based emission factors were found in the range of 10-30% biomass blending ratio. With an increase in the moisture content in the biomass, decreases in combustion temperature, SO{sub 2}, NOx and CO{sub 2} emissions were observed, while an increase in CO emissions was found. It has also been observed that chemical kinetics may play an important role compared to mass diffusion in the co-firing process and the change in biomass grinding size does not have much effect on the fuel burning rate and pollutant emissions tinder the current experimental conditions.

  15. Determination of RH-5849 and indoxacarb in rice straw, rice husk, brown rice and soil using liquid chromatography-tandem triple quadrupole mass spectrometry following extraction with QuEChERS method.

    Li, Zhurui; Zhao, Xiaozhen; Chen, Jiaojiao; Wu, Yue; Zhang, Jing; Zhang, Kankan; Hu, Deyu


    A fast and simple analytical method was developed for the simultaneous determination of RH-5849 and indoxacarb in soil, rice straw, rice husk and brown rice. QuEChERS (quick, easy, cheap, effective, rugged and safe) method was used for extraction, and liquid chromatography with tandem triple quadrupole mass spectrometry was used for quantification. The matrix-matched calibration plots were linear in the range between 25 and 5000 μg/L for soil, rice straw, rice husk and brown rice samples. All determination coefficients (R(2) ) were ≥0.9962. The limits of detection and quantification were 1.5 and 5 μg/kg, respectively. Recoveries at three fortification levels ranged between 79.5 and 97.9% with relative standard deviations <11%. The developed method was validated and applied for the analysis of dissipation study samples. For field experiments, the half-lives of RH-5849 and indoxacarb in rice straw were 11.93 and 5.83 days, respectively. The method was demonstrated to be reliable for the routine monitoring of RH-5849 and indoxacarb in rice samples. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Utilization of Palm Oil Fuel Ash and Rice Husks in Unfired Bricks for Sustainable Construction Materials Development

    Saleh A.M


    Full Text Available The production of sustainable construction component could prevent and control the pollution and environmental degradation in Malaysia. This is a key area in Malaysia’s Green Strategies (Ministry of Science, Technology and the environment, 2002. This paper reports on the laboratory investigation to establish the potential of utilizing Palm Oil Fuel Ash (POFA and Rice Husk (RH in developing green construction components. Malaysian Palm Oil Council (MPOC reported that currently Malaysia’s contribution to world palm oil production is 39% and has taken 44% of world exports. Consequently it will increase the POFA production in palm oil manufacturing and this waste sometimes dispose in open area near the factory. On the other hand Malaysia also producing more 300k hectares of paddy production, thus rice husk is also a concern as an agricultural waste. The research objective is to study on the potential of utilizing of agricultural waste in developing of green bricks. This research involved laboratory investigations. In this research 2% - 10% of POFA and 1% - 5% RH were used in the mix composition of the brick’s weight. Addition of POFA was aimed to reduce the cement usage and RH was added to reduce sand in the bricks. The bricks were manually pressed in Materials Laboratory in Faculty of Architecture, Planning and Surveying, UiTM Shah Alam. The result showed that the addition of POFA and RH are able to reduce the density but in contrast the compressive strength were decrease compare to the control unit.

  17. Preparation and characterization of electron-beam treated HDPE composites reinforced with rice husk ash and Brazilian clay

    Ortiz, A.V., E-mail: [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil); Teixeira, J.G.; Gomes, M.G.; Oliveira, R.R. [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil); Díaz, F.R.V. [Metallurgical and Materials Engineering Department, Polytechnic School, University of São Paulo Av. Prof. Mello de Morais 2463, São Paulo, SP 05508-900 (Brazil); Moura, E.A.B. [Nuclear and Energy Research Institute, IPEN-CNEN/SP Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000 (Brazil)


    Highlights: • We examine changes in HDPE properties when waste and clay are used as reinforcement. • The addition of only 3% of clay leads to important gains in HDPE properties. • The use of electron-beam contributes to greater improvements in material properties. • We observe 85% of cross-linking degree for the HDPE when treated with e-beam. - Abstract: This work evaluates the morphology, mechanical and thermo-mechanical properties of high density polyethylene (HDPE) composites. HDPE reinforced with rice husk ashes (80:20 wt%), HDPE reinforced with clay (97:3 wt%) and HDPE reinforced with both rice husk ashes and clay(77:20:3 wt%) were obtained. The Brazilian bentonite chocolate clay was used in this study. This Brazilian smectitic clay is commonly used to produce nanocomposites. The composites were produced by melting extrusion process and then irradiation was carried out in a 1.5 MeV electron-beam accelerator (room temperature, presence of air). Comparisons using the irradiated and non-irradiated neat polymer, and the irradiated and non-irradiated composites were made. The materials obtained were submitted to tensile, flexural and impact tests. Additionally HDT, SEM and XRD analyses were carried out along with the sol–gel analysis which aimed to assess the cross-linking degree of the irradiated materials. Results showed great improvement in most HDPE properties and a high cross-linking degree of 85% as a result of electron-beam irradiation of the material.

  18. Evaluation of the Performance and Microstructure of Ecofriendly Construction Bricks Made with Fly Ash and Residual Rice Husk Ash

    Chao-Lung Hwang


    Full Text Available This research presents the engineering performance and the microstructural characterization of ecofriendly construction bricks that were produced using a binder material made from a mixture of class-F fly ash (FA and residual rice husk ash (RHA. Unground rice husk ash (URHA was used as a partial fine aggregate substitute (0–40%. The solid bricks of 220 × 105 × 60 mm in size were prepared by mixing FA and RHA with an alkaline solution and fine aggregates, formed by compressing the mixture in a steel mold under 35 MPa of forming pressure, and then cured at 35°C and 50% relative humidity until the required testing ages. The tests of compressive strength, water absorption, and bulk density were conducted in accordance with relevant Vietnamese standards in order to estimate the effect of the URHA content on the engineering performance of the hardened bricks. Scanning electron microscopy (SEM, X-ray diffraction (XRD, and Fourier transform infrared spectroscopy (FTIR were performed to determine the microstructure and the phase composition of the brick samples. The results show that properties of these bricks conformed to relevant Vietnamese standards. Therefore, FA and RHA are potential candidate materials for producing ecofriendly construction bricks using geopolymerization technology.

  19. Superabsorbent nanocomposite synthesis of cellulose from rice husk grafted poly(acrylate acid-co-acrylamide)/bentonite

    Helmiyati; Abbas, G. H.; Kurniawan, S.


    Superabsorbent nanocomposite synthesis of cellulose rice husk as the backbone with free radical polymerization method in copolymerization grafted with acrylic acid and acrylamide monomer. The cellulose was isolated from rice husk with mixture of toluene and ethanol and then hemicellulose and lignin were removed by using potassium hydroxide 4% and hydrogen peroxide 2%. The obtained cellulose rendement was 37.85%. The functional group of lignin analyzed by FTIR spectra was disappeared at wavenumber 1724 cm-1. Crystal size of the obtained isolated cellulose analyzed by XRD diffraction pattern was 34.6 nm, indicated the nanocrystal structure. Copolymerization was performed at temperature of 70°C with flow nitrogen gas. Initiator and crosslinking agent used were potassium persulfate and N‧N-methylene-bis-acrylamide. The swelling capacity of water and urea showed the results was quite satisfactory, the maximum swelling capacity in urea and water were 611.700 g/g and 451.303 g/g, respectively, and can be applied in agriculture to absorb water and urea fertilizer.

  20. Determination of Relationship between Dielectric Properties, Compressive Strength, and Age of Concrete with Rice Husk Ash Using Planar Coaxial Probe

    Piladaeng Nawarat


    Full Text Available This paper deals with an investigation of the dielectric properties of concretes that includes rice husk ash using a planar coaxial probe. The planar coaxial probe has a planar structure with a microstrip and coaxial features. The measurement was performed over the frequency range of 0.5-3.5 GHz, and concrete specimens with different percentages of rice husk ash were tested. The results indicated that the dielectric constant of the concretes was inversely proportional to the frequency, while the conductivity was proportional to the frequency. The dielectric constant decreased with the increasing age of the concrete at the frequency of 1 GHz. The conductivity of the concrete decreased with the increasing age of the concrete at the frequency of 3.2 GHz. In addition, the dielectric constant and the conductivity decreased when the compressive strength increased. It was also shown that the obtained dielectric properties of the concrete could be used to investigate the relationship between the compressive strength and age of the concrete. Moreover, there is an opportunity to apply the proposed probe to determine the dielectric properties of other materials.

  1. Fabrication of Activated Rice Husk Charcoal by Slip Casting as a Hybrid Material for Water Filter Aid

    Tuaprakone, T.; Wongphaet, N.; Wasanapiarnpong, T.


    Activated charcoal has been widely used as an odor absorbent in household and water purification industry. Filtration equipment for drinking water generally consists of four parts, which are microporous membrane (porous alumina ceramic or diatomite, or porous polymer), odor absorbent (activated carbon), hard water treatment (ion exchange resin), and UV irradiation. Ceramic filter aid is usually prepared by slip casting of alumina or diatomite. The membrane offers high flux, high porosity and maximum pore size does not exceed 0.3 μm. This study investigated the fabrication of hybrid activated charcoal tube for water filtration and odor absorption by slip casting. The suitable rice husk charcoal and water ratio was 48 to 52 wt% by weight with 1.5wt% (by dry basis) of CMC binder. The green rice husk charcoal bodies were dried and fired between 700-900 °C in reduction atmosphere. The resulting prepared slip in high speed porcelain pot for 60 min and sintered at 700 °C for 1 h showed the highest specific surface area as 174.95 m2/g. The characterizations of microstructure and pore size distribution as a function of particle size were investigated.

  2. Biogenic hierarchical TiO₂/SiO₂ derived from rice husk and enhanced photocatalytic properties for dye degradation.

    Dalong Yang

    Full Text Available BACKGROUND: Rice husk, an agricultural bioresource, is utilized as a non-metallic bio-precursor to synthesize biogenic hierarchical TiO₂/SiO₂ (BH-TiO₂/SiO₂ and the products are applied to dye degradation. METHODOLOGY/PRINCIPAL FINDINGS: The as-prepared BH-TiO₂/SiO₂ samples are characterized by X-ray diffraction(XRD, X-ray photoelectron spectroscopy(XPS, nitrogen-adsorption measurement, UV-vis spectroscopy and electronic paramagnetic resonance (EPR. The results show that BH-TiO₂/SiO₂ possesses both anatase and rutile phases with amorphous SiO₂ as background, which contains mesopore structure, and nitrogen derived from original rice husk is self-doped into the lattice. Besides, the light-harvesting within the visible-light range of BH-TiO₂/SiO₂ has been enhanced. Moreover, the catalytic activity of BH-TiO₂/SiO₂ has been proven by EPR, and both the photocatalytic activity and stability of BH-TiO₂/SiO₂ are improved as well, which has been illustrated by cycled degradation of methylene blue dye under irradiation. CONCLUSIONS/SIGNIFICANCE: This work provides a good way to combine natural hierarchical porous structure with synthetic material chemistry based on available biomass in the vast natural environment for the sustainable development of human society, and extends potentials of biomass in applications such as photocatalysts, sunlight splitting water and so forth.

  3. Treatment of Wastewater from a Dairy Industry Using Rice Husk as Adsorbent: Treatment Efficiency, Isotherm, Thermodynamics, and Kinetics Modelling

    Uttarini Pathak


    Full Text Available Effluent from milk processing unit contains soluble organics, suspended solids, and trace organics releasing gases, causing taste and odor, and imparting colour and turbidity produced as a result of high consumption of water from the manufacturing process, utilities and service section, chemicals, and residues of technological additives used in individual operations which makes it crucial matter to be treated for preserving the aesthetics of the environment. In this experimental study after determination of the initial parameters of the raw wastewater it was subjected to batch adsorption study using rice husk. The effects of contact time, initial wastewater concentration, pH, adsorbent dosage, solution temperature and the adsorption kinetics, isotherm, and thermodynamic parameters were investigated. The phenomenon of adsorption was favoured at a lower temperature and lower pH in this case. Maximum removal as high as 92.5% could be achieved using an adsorbent dosage of 5 g/L, pH of 2, and temperature of 30°C. The adsorption kinetics and the isotherm studies showed that the pseudo-second-order model and the Langmuir isotherm were the best choices to describe the adsorption behavior. The thermodynamic parameters suggested that not only was the adsorption by rice husk spontaneous and exothermic in nature but also the negative entropy change indicated enthalpy driven process.

  4. Theoretical and experimental spectroscopic analysis by FTIR in the effect of the silanes on the chemical modification of the surface of rice husk

    R. Salgado-Delgado; A.M. Salgado-Delgado


    The development of new fibrous composites with specific properties has attracted a big interest in the development of new technologies. One of the biggest problems in this area is the improvement of the fiber/matrix interface to increase the mechanical properties in the final composite. In this work, surface chemical modifications of the rice husk (by-product of the rice industry) were carried out to achieve a better compatibility with diverse polymeric matrices. These modificatio...

  5. A novel vortex-fluidized bed combustor with two combustion chambers for rice-husk fuel

    Madhiyanon, T.


    Full Text Available A novel vortexing-fluidized bed combustor (VFBC using rice-husk as fuel was developed and presented. The combined characteristics of vortex combustion and fluidized bed combustion are the main features of the VFBC, which was designed to achieve high thermal capacity (MWth m-3, high thermal efficiency and low diameter to height ratio. The VFBC comprises a vertical cylinder chamber and a conical base, which provides a bed for incompletely combusted fuel. The overall dimensions are 1.10 m in height and 0.40 m in diameter. To evaluate combustor performance, the specific feed rate of fuel and mass flow rates of the primary, secondary, and tertiary air were varied independently of one another. The combustion appeared into two zones characterized by different combustion behaviors, i.e. 1 vortext combustion above the vortex ring and 2 fluidized bed combustion below the vortex ring. The fluidized bed zone has uniform temperature distributions across the cross-section of the combustor. The swirling of air above the vortex ringand the vortex ring itself played important roles in preventing the escape of combustion particulates. Bottomash appeared as fine black and grey particles of ash, which ranged in size from 200 to 600 µm. Fluidizationcould be initiated without the assistance of any inert material mixed into the bed. The experimental resultsindicated that thermal efficiency did not depend on the secondary or tertiary airflows, but was significantlyinfluenced by the excess air resulting from the combined total of the three airflows. The introduction of thetertiary airflow helped maintaining the temperature inside the combustor within acceptable levels. According to experimental conditions, i.e. a specific feed rate of 240 kg h-1m-3 and excess air (157%, it was found that the VFBC could achieve an exit gas temperature of 1060ºC, thermal efficiency of 95%, and thermal capacity of 0.91 MWth m-3. The amounts of CO2, CO, and O2 gases emitted were directly

  6. Product yields and characteristics of rice husk, rice straw and corncob during fast pyrolysis in a drop-tube/fixed-bed reactor

    Janewit Wannapeera


    Full Text Available Fast pyrolysis of rice husk, rice straw and corncob were investigated in a newly constructed drop-tube/fixed-bedreactor, which enables pyrolysis experiments under conditions closely simulating those occurring in commercial gasifierssuch as fluidised-bed gasifiers. Biomass samples were pyrolysed with a fast heating rate (i.e. > 1,000oC s-1, up to 850oC andholding times ranging from 1 to 10,800 seconds. Within 1 second after the biomass was injected into the reactor, considerableweight loss occurred instantaneously, leaving only a small amount of char, i.e. ~10-30 %. For all three samples, theweight loss continued throughout the range of holding times used but at an extremely slow rate, i.e. 1.3 % hr-1. The weightloss rates observed for the three biomass samples were affected by the proportion of the biomass chemical componentsas well as the metal species contents. Corncob, which had the lowest lignin content but highest cellulose content, had thehighest pyrolysis weight loss rate. On the other hand, rice husk containing a relatively high lignin content, had the lowestpyrolysis rate. The metal species (Na, K, Ca and Mg were found to increase devolatilisation yield depending on theircontents in biomass. The influence of the metal species was the most pronounced for rice straw, having the highest totalmetal species content. As the pyrolysis progressed, each biomass exhibited different char characteristics. Scanning electronmicroscopy (SEM pictures clearly showed the individual changes in geometry for all biomass-derived chars as well astheir decrease in combustion reactivities. The gas formation profiles for all three biomass samples showed almost the sametrend, with CO contributed by cellulose decomposition as the major gas product.

  7. Agricultural waste as household fuel: techno-economic assessment of a new rice-husk cookstove for developing countries.

    Vitali, Francesco; Parmigiani, Simone; Vaccari, Mentore; Collivignarelli, Carlo


    In many rural contexts of the developing world, agricultural residues and the organic fraction of waste are often burned in open-air to clear the lands or just to dispose them. This is a common practice which generates uncontrolled emissions, while wasting a potential energy resource. This is the case of rice husk in the Logone Valley (Chad/Cameroon). In such a context household energy supply is a further critical issue. Modern liquid fuel use is limited and traditional solid fuels (mainly wood) are used for daily cooking in rudimentary devices like 3-stone fires, resulting in low efficiency fuel use, huge health impacts, increasing exploitation stress for the local natural resources. Rice husk may be an alternative fuel to wood for household energy supply. In order to recover such a biomass, the authors are testing a proper stove with an original design. Its lay-out (featuring a metal-net basket to contain the fuel and a chimney to force a natural air draft) allows a mix of combustion/gasification of the biomass occurring in a completely burning fire, appropriate for cooking tasks. According to results obtained with rigorous test protocols (Water Boiling Test), different lay-outs have been designed to improve the performance of the stove. Technical and economic issues have been addressed in the development of such a model; building materials have been chosen in order to guarantee a cost as low as possible, using locally available items. The feasibility of the introduction of the stove in the studied context was assessed through an economic model that keeps into account not only the technology and fuel costs, but also the energy performance. According to the model, the threshold for the trade-off of the stove is the use of rice husk to cover 10-15% of the household energy needs both with traditional fireplaces or with improved efficiency cookstoves. The use of the technology proposed in combination with improved woodstove would provide householders with an

  8. Effect of Nano Silica on the Physical Property of Porous Concrete Pavement

    Yusak, Mohd Ibrahim Mohd; Ezree Abdullah, Mohd; Putra Jaya, Ramadhansyah; Rosli Hainin, Mohd; Ibrahim, Mohd Haziman Wan


    Rice husk can be categorized as an organic waste material from paddy industries. Silica is a major inorganic element of the rice husk. The aim of present study is to evaluate the effect of Nano silica on the physical properties of porous concrete pavement. Rice husk has been burned in the furnace (650°C for 6 hours) and ground for four different grinding times (33, 48, 63 and 81 hours). Five types of mixes were prepared to evaluate the different Nano silica grinding time. A Nano silica dosage of 10% by weight of binder was used throughout the experiments. The physical properties were examined through compressive strength, transmission electron microscopy and x-ray fluorescence. The experimental results indicate that the different Nano size gives a different effect to porous concrete strength. Based on the results obtained, Nano silica ground for 63 hours (65.84nm) gives the best result and performance to porous concrete pavement specimens.

  9. Hydrogen-rich gas production via CaO sorption-enhanced steam gasification of rice husk: a modelling study.

    Beheshti, Sayyed Mohsen; Ghassemi, Hojat; Shahsavan-Markadeh, Rasoul; Fremaux, Sylvain


    Gasification is a thermochemical process in which solid or liquid fuels are transformed into synthesis gas through partial oxidation. In this paper, a kinetic model of rice husk gasification has been developed, which is interesting for the applications of the syngas produced. It is a zero-dimensional, steady-state model based on global reaction kinetic, empirical correlation of pyrolysis and is capable of predicting hydrogen yield in the presence of sorbent CaO. The model can also be used as a useful tool to investigate the influence of process parameters including steam/biomass ratio, CaO/fuel ratio (CaO/Fuel), and gasification temperature on hydrogen efficiency, CO2 capture ratio (CCR), and average carbonation conversion (Save). Similar to hydrogen formation, CCR also increases with increasing CaO/Fuel, but an opposite trend is exhibited in Save. Model predictions were compared with available data from the literature, which showed fairly good agreement.

  10. Application of mineral bed materials during fast pyrolysis of rice husk to improve water-soluble organics production.

    Li, R; Zhong, Z P; Jin, B S; Zheng, A J


    Fast pyrolysis of rice husk was performed in a spout-fluid bed to produce water-soluble organics. The effects of mineral bed materials (red brick, calcite, limestone, and dolomite) on yield and quality of organics were evaluated with the help of principal component analysis (PCA). Compared to quartz sand, red brick, limestone, and dolomite increased the yield of the water-soluble organics by 6-55% and the heating value by 16-19%. The relative content of acetic acid was reduced by 23-43% with calcite, limestone and dolomite when compared with quartz sand. The results from PCA showed all minerals enhanced the ring-opening reactions of cellulose into furans and carbonyl compounds rather than into monomeric sugars. Moreover, calcite, limestone, and dolomite displayed the ability to catalyze the degradation of heavy compounds and the demethoxylation reaction of guaiacols into phenols. Minerals, especially limestone and dolomite, were beneficial to the production of water-soluble organics.

  11. Preparation of SiO2 nanowires from rice husks by hydrothermal method and the RNA purification performance

    Huang, Meiyan; Cao, Jianping; Meng, Xing; Liu, Yangsi; Ke, Wei; Wang, Jialiang; Sun, Ling


    In this study, SiO2 nanowires were prepared by using rice husks as silicon source via a hydrothermal method. The microstructure, thermal stability and morphology of SiO2 nanowires were characterized by X-ray diffraction, infrared spectroscopy, thermal gravimetric analysis and scanning electron microscope. SiO2 nanowires with a diameter of 30-100 nm were obtained and the formation mechanism of SiO2 nanowires during the hydrothermal reaction was proposed. The SiO2 nanowires were introduced into membrane spin columns to isolate RNA and the values of A260/280 and A260/230 were 2.0-2.1 and 1.8-2.0, respectively, which shows the SiO2 nanowires were effective for RNA purification.




    Full Text Available Activated carbons from agro-industrial wastes; rice husk; were prepared by physical and chemical activation using phosphoric acid as the dehydrating agent. A two-stage activation process method was used; with semi-carbonisation stage at 200oC for 15 minutes as the first stage followed by an activation stage at 500oC for 45 minutes as the second stage. The precursor material with the impregnation agent was exposed straightaway to semi-carbonization and activation temperature unlike the specific temperature progression as reported in the literature. All experiments were conducted in a laboratory scale muffle furnace under static conditions in a self generated atmosphere covering process parameters such as impregnation ratios. We found that by using this method, the AC5 had the highest iodine number and methylene blue adsorption capacity which was 506.6 mg/g and 319.0 mg/g respectively.

  13. Photostability Characterization of Wood Polymer Composites of Polyvinyl Chloride and Rice Husk to Ultra-Violet Irradiation Exposure

    Jais Farhana Hazwanee M.


    Full Text Available In this study, the photostability of wood polymer composites (WPC was assessed by using ultra-violet accelerated weathering test. Meanwhile, the mechanical properties of WPC show strength improvement at prolonged UV irradiation exposure with 43.21 MPa and maximum strain of 4.08 % at 5000 hours and 1000 hours UV irradiation exposure respectively. The colour stability of WPC was improved by addition of Ultraviolet (UV stabilizer during pre-mixing process which shows positive effect on the colour stability and prevented chalking of the composites for external use. Generally, discolourations of WPC during test exposure were caused by degradation of both wood and plastic. Therefore, incorporation with pigments and other additives gives improvement to the photostability of WPC. This is based on the increment of WPCs mechanical property while the morphological fracture surface of dumbbell test specimens revealed the pull out rice husk fiber which contributed to the distribution of load in the WPC samples.

  14. Evaluation of nitric and acetic acid resistance of cement mortars containing high-volume black rice husk ash.

    Chatveera, B; Lertwattanaruk, P


    This paper presents the performance of cement mortar containing black rice husk ash (BRHA) under nitric and acetic acid attacks. The BRHA, collected from an electrical generating power plant that uses rice husk as fuel, was ground using a grinding machine. The compressive strength loss, weight loss, and expansion of mortars under nitric and acetic acid attack were investigated. The test results of BRHA properties in accordance with the ASTM C 618 standard found that the optimal grinding time was 4 h as this achieved a Blaine fineness of 5370 cm(2)/g. For parametric study, BRHA were used as a Portland cement Type 1 replacement at the levels of 0%, 10%, 20%, 30%, 40%, and 50% by weight of binder. The water-to-binder ratios were 0.55, 0.60, and 0.65. From test results, when the percentage replacements of BRHA in cement increased, it was observed that the strength loss and weight loss of mortars containing BRHA under acetic acid attack were higher than those of the mortars against nitric acid attack. It was found that, of the various BHRA mortars, the strength loss and weight loss due to nitric and acetic acid attacks were the lowest in the mortar with 10% BRHA replacement. For 10%, 20% and 30% BRHA replacements, the rate of expansion of the BRHA mortar decreased when compared with the control mortar. For the mortars with other percentage replacements of BRHA, the rate of expansion increased. Furthermore, the effective water-to-binder ratios of control and BRHA mortars were the primary factor for determining the durability of mortar mixed with BRHA.

  15. Lightweight Heat Resistant Geopolymer-based Materials Synthesized from Red Mud and Rice Husk Ash Using Sodium Silicate Solution as Alkaline Activator

    Hoc Thang Nguyen


    Full Text Available Geopolymer is an inorganic polymer composite with potentials to replace Ordinary Portland Cement (OPC-based materials in the future because of its lower energy consumption, minimal CO2 emissions and lower production cost as it utilizes industrial waste resources. Hence, geopolymerization and the process to produce geopolymers for various applications like building materials can be considered as green industry. Moreover, in our study, the raw materials we used are red mud and rice husk ash, which are are industrial and agricultural wastes that need to be managed to reduce their impact to the environment. The red mud and rice husk ash combined with sodium silicate (water glass solution were mixed to form geopolymer materials. Moreover, the geopolymer specimens were also tested for heat resistance at a temperature of 1000°C for 2 hours. Results suggest high heat resistance with an increase of compressive strength after exposed at high temperature.

  16. Synthesis and characterisation of composite based biohydroxyapatite bovine bone mandible waste (BHAp) doped with 10 wt % amorphous SiO2 from rice husk by solid state reaction

    Asmi, Dwi; Sulaiman, Ahmad; Oktavia, Irene Lucky; Badaruddin, Muhammad; Zulfia, Anne


    Effect of 10 wt% amorphous SiO2 from rice husk addition on the microstructures of biohydroxyapatite (BHAp) obtained from bovine bone was synthesized by solid state reaction. In this study, biohydroxyapatite powder was obtained from bovine bone mandible waste heat treated at 800 °C for 5 h and amorphous SiO2 powder was extracted from citric acid leaching of rice husk followed by combustion at 700°C for 5 h. The composite powder then mixed and sintered at 1200 °C for 3 h. X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM) techniques are utilized to characterize the phase relations, functional group present and morphology of the sample. The study has revealed that the processing procedures played an important role in microstructural development of BHAp-10 wt% SiO2 composite. The XRD study of the raw material revealed that the primary phase material in the heat treated of bovine bone mandible waste is hydroxyapatite and in the combustion of rice husk is amorphous SiO2. However, in the composite the hydroxyapatite, β-tricalcium phosphate, and calcium phosphate silicate were observed. The FTIR result show that the hydroxyl stretching band in the composite decrease compared with those of hydroxyapatite spectra and the evolution of morphology was occurred in the composite.


    Abdalla M. Alzrog


    Full Text Available The ecological effects of heavy metals or trace elements in soils are closely related to their contents and speciation in the soil. They play a significant role in the metabolic pathways throughout the growth and development of plants when presented in required concentration. In this study the effect of rice husk and coco peat media on the cadmium uptake by chilli plant (Capsicum annuum L was investigated. The experiment was conducted in complete randomized block design (RBD comprising of three replications. Various concentrations of Cd were dosed to the media once after one week of transplantation. All the required agricultural practices were applied uniformly until harvesting. Cd accumulation in roots, shoots and fruits were analyzed during vegetative, flowering and maturity stages, using atomic absorption spectrophotometric analysis (AAS. Results showed that both planting media exhibited higher accumulation of Cd in roots and shoots at the vegetative stage. The accumulated amount was found significantly dependent on the Cd dose injected to the media. Consequently, micronutrients contents and plant growth were also affected. The accumulated Cd in fruits was found slightly less in rice husk than coco peat media and above the prescribed safety limits recommended by FAO and WHO. Rice husk has higher impact on the microneutrients absorption than coco peat media. In this study, root length, plant hight, dry weight and fruits showed small differences among growing media.

  18. Chemical characterization and oxidative potential of particles emitted from open burning of cereal straws and rice husk under flaming and smoldering conditions

    Fushimi, Akihiro; Saitoh, Katsumi; Hayashi, Kentaro; Ono, Keisuke; Fujitani, Yuji; Villalobos, Ana M.; Shelton, Brandon R.; Takami, Akinori; Tanabe, Kiyoshi; Schauer, James J.


    Open burning of crop residue is a major source of atmospheric fine particle emissions. We burned crop residues (rice straws, barley straws, wheat straws, and rice husks produced in Japan) in an outdoor chamber and measured particle mass, composition (elemental carbon: EC, organic carbon: OC, ions, elements, and organic species), and oxidative potential in the exhausts. The fine particulate emission factors from the literature were within the range of our values for rice straws but were 1.4-1.9 and 0.34-0.44 times higher than our measured values for barley straw and wheat straw, respectively. For rice husks and wheat straws, which typically lead to combustion conditions that are relatively mild, the EC content of the particles was less than 5%. Levoglucosan seems more suitable as a biomass burning marker than K+, since levoglucosan/OC ratios were more stable than K+/particulate mass ratios among crop species. Stigmasterol and β-sitosterol could also be used as markers of biomass burning with levoglucosan or instead of levoglucosan. Correlation analysis between chemical composition and combustion condition suggests that hot or flaming combustions enhance EC, K+, Cl- and polycyclic aromatic hydrocarbons emissions, while low-temperature or smoldering combustions enhance levoglucosan and water-soluble organic carbon emissions. Oxidative potential, measured with macrophage-based reactive oxygen species (ROS) assay and dithiothreitol (DTT) assay, of open burning fine particles per particulate mass as well as fine particulate emission factors were the highest for wheat straws and second highest for rice husks and rice straws. Oxidative potential per particulate mass was in the lower range of vehicle exhaust and atmosphere. These results suggest that the contribution of open burning is relatively small to the oxidative potential of atmospheric particles. In addition, oxidative potential (both ROS and DTT activities) correlated well with water-insoluble organic species

  19. Thermogravimetric-Mass Spectrometry Analysis and Pyrolysis Kinetic of Rice Husk and Rice Straw%稻壳和稻草的热重-质谱分析及其反应动力学

    姚锡文; 许开立; 贾彦强; 张秀敏


    In the nitrogen atmosphere,thermogravimetry-mass spectrometry(TG /MS)was used in combination to compare the pyrolysis behavior of rice husk and rice straw at the heating rates of 5 ℃/min and 20 ℃/min,and the release rule of small molecule gas (CO,CO2 ,CH4 ,H2 )product with the change of temperature and heating rates was obtained.The results show that the pyrolysis process of rice husk and rice straw can be divided into dewatering and drying warm-up solution stage,volatile component precipitation fast pyrolysis stage and residue pyrolysis carbonization stage.The total weight loss rate of rice straw pyrolysis is about 75%,while rice husk is about 55%,and the index value of rice straw pyrolysis characteristics is higher than that of rice husk. The release intensity of ion current of main biomass gas composition (CO,CH4 and H2 )in the rice straw pyrolysis process is obviously higher than that of rice husk.The pyrolysis kinetic parameters were calculated by using Coats-Redfern method.The apparent activation energy and volatile component initial precipitation temperature of rice straw are lower than those of rice husk, which accord with the results of experiment,and indicate that the pyrolysis performance of rice straw is better than that of rice husk under uniform conditions.%采用热重-质谱(TG -MS)联用对比研究了氮气气氛中稻壳和稻草在升温速率分别为5,20℃/min时的热解行为,分析得到了稻壳和稻草热裂解过程产生的小分子气相产物(CO,CO2,CH4,H2)随温度和升温速率变化的释放规律。结果表明:稻壳和稻草的热解过程可分为脱水干燥预热解阶段、挥发分析出快速热解阶段和残余物裂解炭化阶段;稻草热解总失重率约为75%,稻壳约为55%,而且稻草的热解特性指数高于稻壳;稻草热解释放生物质燃气主要成分(CO,CH4,H2)的离子流强度明显高于稻壳;用 Coats -Redfern法计算生物质的热解动力学参数,表观活化能和挥发

  20. removal of heavy metal ions from aqueous solution using rice husks ...


    concentration of 21 - 27 mg/L at pH 4 were employed. Both Langmuir and ... different conventional physico-chemical methods have ... mesoporous silica with a high density of ... Zr, into the silica framework (Rohaizer et al. 2013). .... In addition, the spectra also show peaks at ... have any significant effect on the adsorption.

  1. Aplicação da cinza da casca do arroz em argamassas de assentamento Application of the rice husk ash in mortars for bricklaying

    Izabelle M. T. Bezerra


    Full Text Available A cinza produzida pela queima da casca do arroz tem potencial para ser utilizada na confecção de argamassas por possuir, em sua constituição, alto teor de sílica (SiO2, podendo ser utilizada também como material pozolânico. Esta pesquisa objetivou verificar a viabilidade da utilização da cinza da casca do arroz (CCA em argamassas de assentamento. Realizou-se a caracterização química e mineralógica da CCA e se determinou o índice de atividade pozolânica. Para as argamassas foi determinado o índice de consistência e, em seguida, confeccionados corpos de prova de referência (sem CCA e também com percentuais de 6, 9, 15, 20 e 30% de CCA, como substituição parcial do cimento, para o traço 1:2:9, em massa, e ensaiados após períodos de cura de 28, 63 e 91 dias para determinação da densidade de massa no estado endurecido, absorção de água e resistência à compressão simples. Os resultados mostram que a CCA apresenta pozolanicidade e os corpos de prova com incorporação da CCA forneceram valores superiores aos de referência com relação às propriedades físicas e mecânicas, devido à provável ocorrência das reações pozolânicas e que a utilização da CCA é viável, tanto do ponto de vista técnico quanto ecológico.The ash produced by the burning of the rice husk presents potential for application in mortar production because has high silica content (SiO2, and so it can be used as pozzolan. This research aimed to verify the viability of rice husk ash (RHA added to mortars for bricklaying. Chemical and mineralogical characterization of RHA was initially carried out and the pozzolanic activity was determined. For the production of mortars, the consistence of each mixture studied was determined and then reference mortars (without CCA and mortars with incorporated RHA were produced with 6, 9, 15, 20 and 30% of RHA in partial substitution of cement for mortar 1:2:9 (mass ratio, in curing period of 28, 63 and 91 days

  2. An investigation of Crater Diameter on Plain Slab Foamed Concrete Rice Husk Ash (FCRHA Exposed to Low Impact Loading

    Hadipramana Josef


    Full Text Available As sustainable material building and construction, the foamed concrete (FC in this investigation was modified by adding the Rice Husk Ash (RHA as sand replacement to increase its strength. Furthermore, this modification material (is called FCRHA treated on impact loading. This investigation was motivated when the plain slab of FCRHA subjected to small impactor, then the nose impactor over all would penetrate into slab target due to porosity of FCRHA. The experimental produced plain slabs FCRHA and FC (as a control with 1400 kg/m3 and 1600 Kg/m3 of densities. In impact test all plain slabs exposed by 40 mm steel blunt nose impactor with various impact velocities. The result showed the crater which produced by impact loading was not found spalling, scabbing, radial crack and widely cratering. This local damage occurred when porosity of FCRHA took over the impact loading. The nose impactor over all considered have been successful penetrated into slab of FCRHA and FC. Therefore, the diameter of crater equals to diameter of impactor. With this certainty, the prediction penetration depth on plain slab FCRHA (also FC can be determined in future investigation. In addition, the penetration of impactor on FCRHA with low impact velocity give the same impression on penetration impactor with high impact velocity on FC.

  3. Esterification of oil adsorbed on palm decanter cake into methyl ester using sulfonated rice husk ash as heterogeneous acid catalyst

    Hindryawati, Noor; Erwin, Maniam, Gaanty Pragas


    Palm Decanter cake (PDC) which is categorized as the waste from palm oil mill has been found to contain residual crude palm oil. The oil adsorbed on the PDC (PDC-oil) can be extracted and potentially used as feedstock for biodiesel production. Feedstock from waste like PDC-oil is burdened with high free fatty acids (FFAs) which make the feedstock difficult to be converted into biodiesel using basic catalyst. Therefore, in this study, a solid acid, RHA-SO3H catalyst was synthesized by sulfonating rice husk ash (RHA) with concentrated sulfuric acid. The RHA-SO3H prepared was characterized with TGA, FTIR, BET, XRD, FE-SEM, and Hammett indicators (methyl red, bromophenol blue, and crystal violet). PDC was found to have about 11.3 wt. % oil recovered after 1 hour extraction using ultrasound method. The presence of sulfonate group was observed in IR spectrum, and the surface area of RHA-SO3H was reduced to 37 m2.g-1 after impregnation of sulfonate group. The RHA-SO3H catalyst showed that it can work for both esterification of free fatty acid which is present in PDC-oil, and transesterification of triglycerides into methyl ester. The results showed highest methyl ester content of 70.2 wt.% at optimal conditions, which was 6 wt.% catalyst amount, methanol to oil molar ratio of 17:1 for 5 hours at 120 °C.


    Veera Horsakulthai


    Full Text Available This study studied the utilization of Bagasse-Rice Husk-Wood Ash (BRWA as an additive for improving the strength and durability of coarse Fly Ash (FA concrete. The ground BRWA was used as an additive for maintaining the consistent slump of FA concrete. The strength, chloride permeability and corrosion resistance were investigated. The chloride permeability of concrete was evaluated using the measurement of coulomb charge as per ASTM C1202 and the corrosion resistance was detected using the Accelerated Corrosion test by Impressed Voltage (ACTIV. The test indicated that the incorporation of ground BRWA as an additive in FA concrete improved potentially both the strength and corrosion resistance, particularly the concrete containing up to 40% FA. While the 60% FA concrete with ground BRWA additive improved significantly in strength, the resistance to corrosion was insignificantly improved. The results showed that the use of ground BRWA as an additive was one approach for its utilization in concrete beyond use as pozzolan. The increase in the use of BRWA in concrete could reduce costs and minimize the environmental problems as well.

  5. Thermodynamic and kinetic studies of biosorption of iron and manganese from aqueous medium using rice husk ash

    Adekola, F. A.; Hodonou, D. S. S.; Adegoke, H. I.


    The adsorption behavior of rice husk ash with respect to manganese and iron has been studied by batch methods to consider its application for water and waste water treatment. The optimum conditions of adsorption were determined by investigating the effect of initial metal ion concentration, contact time, adsorbent dose, pH value of aqueous solution and temperature. Adsorption equilibrium time was observed at 120 min. The adsorption efficiencies were found to be pH dependent. The equilibrium adsorption experimental data were found to fit the Langmuir, Freundlich and Temkin isotherms for iron, but fitted only Langmuir isotherm for manganese. The pseudo-second order kinetic model was found to describe the manganese and iron kinetics more effectively. The thermodynamic experiment revealed that the adsorption processes involving both metals were exothermic. The adsorbent was finally applied to typical raw water with initial manganese and iron concentrations of 3.38 mg/l for Fe and 6.28 mg/l, respectively, and the removal efficiency was 100 % for Mn and 70 % for Fe. The metal ions were desorbed from the adsorbent using 0.01 M HCl, it was found to quantitatively remove 67 and 86 % of Mn and Fe, respectively, within 2 h. The results revealed that manganese and iron are considerably adsorbed on the adsorbent and could be an economic method for the removal of these metals from aqueous solutions.

  6. The Predisposition of Iraqi Rice Husk to Remove Heavy Metals from Aqueous Solutions and Capitalized from Waste Residue

    Mohammed Nsaif


    Full Text Available This study is deal with study the potential of Iraqi Rice Husk (IRH on the removal of three heavy metals pollutant which were (Mg, Mn and Mo ions from industrial wastewater using different design parameters by adsorption process. Results show that the removal efficiency were (93.95, 97.18 and 95.26 % for heavy metal (Mg, Mn and Mo respectively from aquatic solution decreased with increasing of initial concentration and flow rate while the removal efficiency increased with increasing absorbance material bed height, pH and feeding temperature. Statistical model is achieved to find an expression relates the overall operating parameters with the removal efficiency for each metal ions used in this investigation in a general equation (each one alone. The samples of (IRH remaining after using it in the removal of (Mg, Mn and Mo heavy metal ions above from Simulated Synthetic Aqueous Solutions (SSAS to investigate the capitalized of it in different methods. Different benefits possess which are: remove the three toxic heavy metals ions contaminated the water, get rid of agricultural waste (IRH, in the same time, produce light and more benefit hydrocarbons from n-heptane isomerization using a type Y-zeolite catalyst synthesis from remaining (IRH and prepare a cheap and active rodenticide.

  7. Removal of Congo Red and Acid Yellow 36 Dye Using Orange Peel and Rice Husk as Absorbent

    K. N. Ranjini


    Full Text Available Many researchers have identified the capability of agricultural wastes as absorbents to remove different types of pollutants including dyes. This study represents the use of orange peel (OP and rice husk (RH to remove two types of dye, Congo Red (CR and Acid Yellow 36 (AY 36 dye and provides simple comparison between granular form of OP and RH and activated form of OP and RH. Both types of dyes are toxic and can cause severe problems to the environment. Factor such as absorbent dosage was studied. Batch absorption studies were conducted at 27˚C with constant stirring at 150 rpm for 2 hours and absorbent dosage of 0.2 to 1.0 g. The results showed that the activated form of OP and RH had the highest removal percentage of CR and AY 36 dyeswhich were up to 100% removal. This study indicates that OP and RH could be employed as low cost materials for the removal of textile dyes from effluents.

  8. Performance evaluation of cement-stabilized pond ash-rice husk ash-clay mixture as a highway construction material

    Deepak Gupta


    Full Text Available This paper reports the results of an investigation carried out on clay soil stabilized with pond ash (PA, rice husk ash (RHA and cement. Modified Proctor compaction tests were performed in order to investigate the compaction behavior of clay, and California bearing ratio (CBR tests were performed to determine the strength characteristics of clay. For evaluation purpose, the specimens containing different amounts of admixtures were prepared. Clay was replaced with PA and RHA at a dosage of 30%–45% and 5%–20%, respectively. The influence of stabilizer types and dosages on mechanical properties of clay was evaluated. In order to study the surface morphology and crystallization characteristics of the soil samples, scanning electron microscopy (SEM and X-ray diffraction (XRD analyses were carried out, respectively. The results obtained indicated a decrease in the maximum dry density (MDD and a simultaneous increase in the optimum moisture content (OMC with the addition of PA and RHA. Multiple linear regression analysis (MLRA showed that the predicted values of CBR tests are in good agreement with the experimental values. Developed stabilized soil mixtures showed satisfactory strength and can be used for construction of embankments and stabilization of sub-grade soil. The use of locally available soils, PA, RHA, and cement in the production of stabilized soils for such applications can provide sustainability for the local construction industry.

  9. Rice husks as a sustainable source of nanostructured silicon for high performance Li-ion battery anodes

    Liu, Nian; Huo, Kaifu; McDowell, Matthew T.; Zhao, Jie; Cui, Yi


    The recovery of useful materials from earth-abundant substances is of strategic importance for industrial processes. Despite the fact that Si is the second most abundant element in the Earth's crust, processes to form Si nanomaterials is usually complex, costly and energy-intensive. Here we show that pure Si nanoparticles (SiNPs) can be derived directly from rice husks (RHs), an abundant agricultural byproduct produced at a rate of 1.2 × 108 tons/year, with a conversion yield as high as 5% by mass. And owing to their small size (10-40 nm) and porous nature, these recovered SiNPs exhibits high performance as Li-ion battery anodes, with high reversible capacity (2,790 mA h g-1, seven times greater than graphite anodes) and long cycle life (86% capacity retention over 300 cycles). Using RHs as the raw material source, overall energy-efficient, green, and large scale synthesis of low-cost and functional Si nanomaterials is possible.

  10. effect of aluminum dross and rice husk ash on thermal and moulding ...


    INTRODUCTION. Silica sand is a good foundry material for casting of both ... Nigerian Journal of Technology (NIJOTECH). Vol. 36, No. ... 3, July 2017 795 cast without the ... also constitutes environmental health hazard. The thermal ... 10 12. Table 5: Sand Specimen with wt. % of RHA. S/No. 1. 2. 3. 4. 5. 6. 7. Specimen RH ...

  11. Synthesis of ZSM-5 zeolite from coal fly ash and rice husk: characterization and application for partial oxidation of methane to methanol

    Krisnandi, Y. K.; Yanti, F. M.; Murti, S. D. S.


    Indonesian fly ash (SiO2/Al2O3 mole ratio = 3.59) was used together with rice husk (SiO2 92%) as raw material for mesoporous ZSM-5 zeolite synthesis. Prior being used, coal fly ash and rice husk were subjected to pre-treatment in order to extract silicate (SiO4 4-) and aluminate (AlO4 5-) and to remove the impurities. Then the ZSM-5 zeolite were synthesized through hydrothermal treatment using two types of templates (TPAOH and PDDA). The as-synthesized ZSM-5 was characterized using FTIR, XRD, SEM-EDX, and BET. The result of FTIR showed peaks at 1250-950 cm-1 (v asymetric T-O), 820-650 cm-1 (v symetric T-O), and at 650-500 cm-1 confirming the presence of the five number ring of the pentasil structure. The result of XRD showed the appearance of certain peaks in the position 2 theta between 7-9° and 22-25° indicative of ZSM-5 structure, but also showed the pattern of low intensity magnetite and hematite. The SEM image showed the rough surface of hexagonal crystals from ZSM-5 structure, indicative of mesoporosity in the structure. EDX result showed Si/Al ratio of 20, while surface area analysis gave SA of 43.16. The ZSM-5 zeolites then was modified with cobalt oxide through impregnation method. The catalytic activity as heterogeneous catalysts in partial oxidation of methane was tested. The result showed that hence the catalytic activity of ZSM-5 and Co/ZSM-5 from fly ash and rice husk were still inferior compared to the pro-analysis sourced-counterpart, they were potential to be used as catalyst in the partial oxidation of methane to methanol.

  12. Rice husk ash supported FeCl2·2H2O:A mild and highly efficient heterogeneous catalyst for the synthesis of polysubstituted quinolines by Friedländer heteroannulation

    Farhad Shirini; Somayeh Akbari-Dadamahaleh; Ali Mohammad-Khah


    Rice husk ash was used as a new, green, and cheap adsorbent for FeCl3. Characterization of the ob-tained reagent showed that rice husk ash supported FeCl2·2H2O was formed. This reagent is effi-cient at catalyzing the synthesis of multisubstituted quinolines by the Friedländer heteroannulation of o-aminoaryl ketones with ketones orβ-diketones under mild reaction conditions. This method-ology allows for the synthesis of a broad range of substituted quinolines in high yields and with excellent regioselectivity in the absence of a solvent.

  13. Palm Ash as an Alternative Source for Silica Production

    Pa Faizul Che


    Full Text Available Agricultural wastes such as palm ash and rice husk have a possibility to be used as a useful renewable source for the production of silica (SiO2. Extensive researches have been carried out to extract silica from agricultural wastes such as rice husk, due to silica as a useful raw material for industrial application. In this study, the environmentally benign and economically effective process to produce SiO2 materials from palm ash has been established by using citric acid leaching, not the conventional strong acids. Results showed that silica can be extracted from palm ash using the citric acid leaching method under the optimum extracting conditions with 700 °C of solution temperature, 60 minutes of reaction time and concentration of citric acid of more than 2 %. The purity of silica extracted is more than 90 %.

  14. Corrosion and wear behaviour of Al–Mg–Si alloy matrix hybrid composites reinforced with rice husk ash and silicon carbide

    Kenneth Kanayo Alaneme; Tolulope Moyosore Adewale; Peter Apata Olubambi


    The corrosion and wear behaviour of Al–Mg–Si alloy matrix hybrid composites developed with the use of rice husk ash (RHA) and silicon carbide (SiC) particulates as reinforcements were investigated. RHA and SiC mixed in weight ratios 0:1, 1:3, 1:1, 3:1, and 1:0 were utilized to prepare 5, 7.5 and 10 wt% of the reinforcing phase with Al Mg Si alloy as matrix using double stir casting process. Open circuit corrosion potential (OCP) and potentiodynamic polarization measurements were used to study...

  15. The Production of Benzaldehyde by Rhizopus oligosporus USM R1 in a Solid State Fermentation (SSF) System of Soy Bean Meal: Rice Husks

    Norliza, A. W.; Ibrahim, C. O.


    The cultivation of Rhizopus oligosporus USM R1 for the production of benzaldehyde, a bitter cherry almond flavour was performed using soya bean meal and rice husks as the substrates. The identification of R. oligosporus USM R1 was performed based on the observation made under light microscope and scanning electron microscope (SEM). The optimum conditions for the SSF in a 250-ml Erlenmeyer flask system were 40% (v/w) water content, substrate particle size of 0.7 mm; inoculum size of 1 x 10^5 s...

  16. Synthesis of silica particles from rice straw waste using a simple extraction method

    Nandiyanto, A. B. D.; Rahman, T.; Fadhlulloh, M. A.; Abdullah, A. G.; Hamidah, I.; Mulyanti, B.


    The purpose of this study was to synthesize silica particles from rice straw waste using a simple extraction method. The experiment was conducted by heating and extracting rice straw waste into basic solution. To get silica particles, the extracted solution was then put into acid solution and heated to remove the remained solvent. The experimental results showed that the aggregated silica particles with sizes of about 200 nm were successfully produced. The XRD and FTIR analysis showed that the final product was silica and free of graphite. However, we found that some KCl component in the final product in which this was possibly from the use of KOH as the extraction agent. Therefore, further studies are still required to synthesize high purity silica particles from rice straw waste.

  17. 由稻壳灰合成P型分子筛%Synthesis of zeolite P from rice husk ash

    付颖寰; 张绥英; 马红超; 陈丽凤; 马春; 宋宇; 董晓丽


    Synthesis of zeolite P by hydrothermal method using rice husk ash as silicon source was optimized. It was found that the maximum calcium exchange ability of zeolite P is 305.4 mg/g when synthesis was carried out at 1.2 of n(Na2O)/n(SiO2) molar ratio, 7.0 of n(SiO2)/n(Al2O3) molar ratio, 25 of n(H2O)/n(Na2O) and 85℃ of crystallizing temperature for 10 h. analysis by X ray diffraction and SEM suggested the better characteristic peak and the narrower grain-size distribution.%以农业废弃物稻壳经酸化处理、焙烧所得的稻壳灰为硅源,通过水热法未经老化过程及添加晶种直接合成了P型分子筛.采用钙交换能力、XRD和SEM对所合成产物的晶体结构、表面形貌和离子交换性能进行了表征.研究结果表明,该工艺合成P型分子筛的最佳条件为:n(Na2O)/n(SiO2)=1.2,n(SiO2)/n(Al2O3)=7.0,n(H2O)/n(Na2O)=25,于85℃反应10 h,在此条件下合成的P型分子筛产品具有较高的结晶度,无杂相且晶粒精细,其钙交换能力达到每克P型分子筛可吸收305.4 ng碳酸钙.

  18. Preparation and Characterization of Impregnated Commercial Rice Husks Activated Carbon with Piperazine for Carbon Dioxide (CO2) Capture

    Masoum Raman, S. N.; Ismail, N. A.; Jamari, S. S.


    Development of effective materials for carbon dioxide (CO2) capture technology is a fundamental importance to reduce CO2 emissions. This work establishes the addition of amine functional group on the surface of activated carbon to further improve the adsorption capacity of CO2. Rice husks activated carbon were modified using wet impregnation method by introducing piperazine onto the activated carbon surfaces at different concentrations and mixture ratios. These modified activated carbons were characterized by using X-Ray Diffraction (XRD), Brunauer, Emmett and Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and Field Emission Scanning Electron Microscopy (FESEM). The results from XRD analysis show the presence of polyethylene butane at diffraction angles of 21.8° and 36.2° for modified activated carbon with increasing intensity corresponding to increase in piperazine concentration. BET results found the surface area and pore volume of non-impregnated activated carbon to be 126.69 m2/g and 0.081 cm3/g respectively, while the modified activated carbons with 4M of piperazine have lower surface area and pore volume which is 6.77 m2/g and 0.015 cm3/g respectively. At 10M concentration, the surface area and pore volume are the lowest which is 4.48 m2/g and 0.0065 cm3/g respectively. These results indicate the piperazine being filled inside the activated carbon pores thus, lowering the surface area and pore volume of the activated carbon. From the FTIR analysis, the presence of peaks at 3312 cm-1 and 1636 cm-1 proved the existence of reaction between carboxyl groups on the activated carbon surfaces with piperazine. The surface morphology of activated carbon can be clearly seen through FESEM analysis. The modified activated carbon contains fewer pores than non-modified activated carbon as the pores have been covered with piperazine.

  19. Synthesis optimization of oil palm empty fruit bunch and rice husk biochars for removal of imazapic and imazapyr herbicides.

    Yavari, Saba; Malakahmad, Amirhossein; Sapari, Nasiman B; Yavari, Sara


    Imidazolinones are a family of herbicides that are used to control a broad range of weeds. Their high persistence and leaching potential make them probable risk to the ecosystems. In this study, biochar, the biomass-derived solid material, was produced from oil palm empty fruit bunches (EFB) and rice husk (RH) through pyrolysis process. Feedstock and pyrolysis variables can control biochar sorption capacity. Therefore, the present study attempts to evaluate effects of three pyrolysis variables (temperature, heating rate and retention time) on abilities of biochars for removal of imazapic and imazapyr herbicides from soil. Response surface methodology (RSM) was used for optimizing the variables to achieve maximum sorption performance of the biochars. Experimental data were interpreted accurately by quadratic models. Based on the results, sorption capacities of both biochars raised when temperature decreased to 300 °C, mainly because of increased biochars effective functionality in sorption of polar molecules. Heating rate of 3°C/min provided optimum conditions to maximize the sorption capacities of both biochars. Retention time of about 1 h and 3 h were found to be the best for EFB and RH biochars, respectively. EFB biochar was more efficient in removal of the herbicides, especially imazapyr due to its chemical composition and higher polarity index (0.42) rather than RH biochar (0.39). Besides, higher cation exchange capacity (CEC) values of EFB biochar (83.90 cmolc/kg) in comparison with RH biochar (70.73 cmolc/kg) represented its higher surface polarity effective in sorption of the polar herbicides.

  20. 稻壳、稗谷脱硅的初步研究%Preliminary Studies on Removal of Silicon in Rice Husk and Barnyard Valley

    刘晓庚; 高梅; 彭冬梅; 王凯; 陈梅梅; 季国淳; 曹崇江


    Preliminary study of important by - product of rice husk and barnyard valley is the removal of silicon. The optimized conditions of the microwave solid -state silicon removal by orthogonal test method are;microwave irradiation time 10 min,400 W microwave power for rice husk and 200W for barnyard valley,the ratio of raw material and desilication agent is 5.0= 1.0( m: m) ,besides the desilication agent is NaOH + Na2CO3 (1: 1). Gap - type approach to the microwave irradiation and the sample size of 40 mesh to 60 mesh is appropriate. Rates of de - husk and barnyard silicon valley are 61.6% and 50.9% beyond optimal conditions, matching with the calculated full optimization theory. Microwave solid - state silicon method is better for rice husk than barnyard valley. Compared with the classic NaOH de - silicon method(the desilication rate is over 98.5% ) ,the microwave solid - state silicon - off method achieves the selectivity of rice husk and barnyard valley,and maintains the silicon skeleton. Apart from these,microwave solid - state silicon - law off the environment is better than the classic one. These two methods almost dissolve the same damage; the retaining cellulose is 67.7% to 68.1% after the silicon removal by microwave method while that of the classic one is 62.5% for rice husk and 62.9% for barnyard valley. There are still some problems to precisely control the process conditions experimental amplification and de -selection mechanism,and so on.%初步研究了稻谷加工的主要副产物稻壳和稗谷的脱硅方法.正交试验得到微波固态脱硅法的最优脱硅条件是:微波时间为10min,微波功率为稻壳400W、稗谷200W,脱硅剂为NaOH+Na2CO3(质量比1:1)、料剂比m原料:m脱硅剂=5.0:1.0.微波方式以间隙式辐照为宜,样品粒度为40目~60目,在此条件下稻壳和稗谷的脱硅率分别为61.6%和50.9%,与优化理论计算结果完全相符.微波固态脱硅法对稻壳的脱硅效果优于稗谷.与经典的Na

  1. Development of hydroponic system using agriculture waste. 1. Characteristics of rice husk charcoal as growth medium and vegetable growth; Suiko saibai ni okeru haikibutsu riyo gijutsu no kaihatsu. 1. Momigara kutan no baichi to shite no tokucho to yasai no seiiku

    Terazoe, H.; Nakaya, K.; Okano, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan)


    Experimental researches were made on rice husk charcoals processed to be used as culture media for hydroponics. Rice husk charcoals with a size of 1 mm or larger retaining the original shape of the rice husk, and with a size of smaller than 1 mm were made for use in the experiment. In the culture media made of these rice husk charcoals, the charcoal with a particle size greater than 1 mm had more air portion than water portion at 6 cm above the water level, and the charcoal with a particle size smaller than 1 mm had poor air permeability. According to the result of immersing the rice husk charcoal in a culture solution, phosphoric acid ion and manganese in the solution decreased by about 35% and calcium by about 10% in the duration of 120 minutes, as a result of having been adsorbed into the rice husk charcoal. On the other hand, chloride ion increased by about 80% and potassium and iron by about 30%, because of having been dissolved out from the charcoal. In cultivating spinach, butterhead lettuce and radish in the rice husk charcoal culture media, the culture medium with charcoal smaller than 1 mm resulted in harvest reduced by about 75% in spinach, and about 10% in butterhead lettuce. 15 refs., 13 figs., 11 tabs.

  2. Phytoremediation of Gold Mine Tailings Amended with Iron-Coated and Uncoated Rice Husk Ash by Vetiver Grass (Vetiveria zizanioides (Linn. Nash

    F. S. Tariq


    Full Text Available This study was undertaken to determine the effects of rice husk ash (RHA and iron-coated rice husk ash (Fe-RHA on phytoavailability of As, Cd, Cr, Cu, Mn, Pb, and Zn to vetiver grass grown in gold mine tailings amended with either RHA or Fe-RHA at 0%, 5%, 10%, and 20% (w/w. The results showed that the RHA amended tailings recorded higher concentration of As in the shoot and the root and higher concentration of Cr and Mn in the root compared to the untreated tailings which was used as a control. The biological accumulation coefficient (BAC and bioconcentration factor (BCF values of the vetiver grass for As and Zn increased with RHA application rate but the biological transfer coefficient (BTC values of As and Zn were decreased. In Fe-RHA amended samples, As concentration in the shoot and root concentrations of Cd and Zn were significantly higher compared to the control. The Fe-RHA treated samples had lower BAC and BTC values for As and Zn than the control. However, the BCF values for those elements were higher than the control. The concentration of Pb was not detected in any of the samples.

  3. Screening of filamentous fungi to produce xylanase and xylooligosaccharides in submerged and solid-state cultivations on rice husk, soybean hull, and spent malt as substrates.

    da Silva Menezes, Bruna; Rossi, Daniele Misturini; Ayub, Marco Antônio Záchia


    We investigated the enzymatic complex produced by selected fungi strains isolated from the environment using the agro-industrial residues rice husk, soybean hull, and spent malt as substrates. Microbial growth was carried out in solid-state cultivation (SSC) and in submerged cultivations (SC) and the enzymatic activities of xylanase, cellulase, β-xylosidase, and β-glucosidase were determined. All substrates were effective in inducing enzymatic activities, with one strain of Aspergillus brasiliensis BLf1 showing maximum activities for all enzymes, except for cellulases. Using this fungus, the enzymatic activities of xylanase, cellulase, and β-glucosidase were generally higher in SSC compared to SC, producing maxima activities of 120.5, 25.3 and 47.4 U g(-1) of dry substrate, respectively. β-xylosidase activity of 28.1 U g(-1) of dry substrate was highest in SC. Experimental design was carried out to optimize xylanase activity by A. brasiliensis BLf1 in SSC using rice husk as substrate, producing maximum xylanase activity 183.5 U g(-1) dry substrate, and xylooligosaccharides were produced and characterized. These results suggest A. brasiliensis BLf1 can be used to produce important lytic enzymes to be applied in the preparation of xylooligosaccharides.

  4. The Production of Benzaldehyde by Rhizopus oligosporus USM R1 in a Solid State Fermentation (SSF System of Soy Bean Meal: Rice Husks

    Norliza, A. W.


    Full Text Available The cultivation of Rhizopus oligosporus USM R1 for the production of benzaldehyde, a bitter cherry almond flavour was performed using soya bean meal and rice husks as the substrates. The identification of R. oligosporus USM R1 was performed based on the observation made under light microscope and scanning electron microscope (SEM. The optimum conditions for the SSF in a 250-ml Erlenmeyer flask system were 40% (v/w water content, substrate particle size of 0.7 mm; inoculum size of 1 x 10^5 spores/g substrate; incubation temperature of 30C; substrate amount of 7 g and the ratio of soy bean meal: rice husks of 50:50%. A maximum benzaldehyde production was obtained when the substrate was agitated after 48 hour for a 96 hour fermentation time. The highest benzaldehyde production obtained after 96 hour cultivation was 5.47 mg g-1 substrate. The supplementation of carbon and nitrogen sources in the substrate mixture revealed an enhancement in the growth and benzyldehyde production. A maximum production of benzaldehyde was obtained with the supplementation of L-phenylalanine, a precursor for benzaldehyde biosynthesis which gave 38.69 mg benzaldehyde/g substrate. This is approximately 6-folds higher compared to the substrates without the supplementation of L-phenylalanine.

  5. Effect of mixing ratio of food waste and rice husk co-digestion and substrate to inoculum ratio on biogas production.

    Haider, Muhammad Rizwan; Zeshan; Yousaf, Sohail; Malik, Riffat Naseem; Visvanathan, Chettiyappan


    Aim of this study was to find out suitable mixing ratio of food waste and rice husk for their co-digestion in order to overcome VFA accumulation in digestion of food waste alone. Four mixing ratios of food waste and rice husk with C/N ratios of 20, 25, 30 and 35 were subjected to a lab scale anaerobic batch experiment under mesophilic conditions. Highest specific biogas yield of 584L/kgVS was obtained from feedstock with C/N ratio of 20. Biogas yield decreased with decrease in food waste proportion. Further, fresh cow dung was used as inoculum to investigate optimum S/I ratio with the selected feedstock. In experiment 2, feedstock with C/N ratio 20 was subjected to anaerobic digestion at five S/I ratios of 0.25, 0.5, 1.0, 1.5 and 2.0. Specific biogas yield of 557L/kgVS was obtained at S/I ratio of 0.25. However, VFA accumulation occurred at higher S/I ratios due to higher organic loadings.

  6. 回收塑料/稻壳粉木塑复合材料的制备及性能研究%Study on the Preparation and Properties of Recycled Plastic/Rice Husk Powder Composites

    王春红; 任子龙; 刘胜凯; 徐贵海; 王瑞


    Recycled plastic/recycled plastic rice husk powder composites were made by extrusion and injection molding process with rice husk powder and nonmedical recycled plastic. The influence of size,content of rice husk powder and surface treatment on the mechanical properties of the composite were investigated. The morphology of the composite was observed by SEM. The results show that the mechanical properties of the recycled plastic/rice husk powder composites first increase and then decrease with increase of the size of rice husk powder,and increase with increase of the content of rice husk powder. Mechanical properties of the composites are best when the content of the rice husk powder with 425 μm is 50%. Compared with recycled plastic,tensile strength,tensile modulus,flexural strength and flexural modulus of the composites reinforced by glass fibre increased by 82.01%, 414.66%,152.62%,436.99%.%以稻壳粉和非医疗废弃物作为原料,采用挤出–注塑工艺制备回收塑料/稻壳粉木塑复合材料,研究了稻壳粉的粒径、含量以及玻璃纤维对复合材料力学性能的影响,用扫描电子显微镜对复合材料的断面进行了观察。结果表明,回收塑料/稻壳粉木塑复合材料的力学性能随稻壳粉粒径的增加先上升后下降,随稻壳粉含量的增加而提高。当稻壳粉质量分数为50%,粒径为425μm时,回收塑料/稻壳粉木塑复合材料综合力学性能最好。当用偶联剂处理稻壳粉和玻璃纤维后,相对于纯回收塑料,复合材料的拉伸强度提高了82.01%,拉伸弹性模量提高了414.66%,弯曲强度提高了152.62%,弯曲弹性模量提高了436.99%。

  7. Pengaruh pemberian abu sekam padi sebagai bahan desikan pada penyimpanan benih terhadap daya tumbuh dan pertumbuhan bibit kakao (The effects of rice husk ash as desiccation material of seed storage on viability and cocoa seedling growth.

    Pudji Rahardjo


    Full Text Available Rice husk ash as desiccation material can be used to maintain seed viability in storage through its ability to absorb humidity during its storage. High relative humidity caused seed moisture content to increase so the respiration rate of seed increases and uses faster food stock. Finally the viability of seed is lost. A research on use of rice husk ash as desiccation material of cocoa seed storage was conducted in Agronomy Laboratory and Kaliwining Experimental Station, Indonesian Coffee and Cocoa Research Institute. Completely Randomized Design was used in this research with treatment of rice husk ash application on cocoa seed as follows: 0 g/100 seeds (A, 5 g/100 seeds (B, 10 g/100 seeds (C, 15 g/100 seeds (D, and 20 g/100 seeds (E. This experiment used four replications. Cocoa seeds were stored in plastic bag within carton box in ambient temperature. The storage periods were 1, 2, and 3 weeks, and parameters of observation consisted of electrical conductivity of dipped water of cocoa seeds, percentage of seed germination, percentage of seed emergence, early growth parameters at one month old including seedlings height of seedling, diameter, leaf number, root length, and dry weight. The result of the experiment showed that the use of rice husk ash at 5-10 g/100 seeds could maintain electrical conductivity of dipped water at low level, percentage of seed germination at 99-100 % and percentage of seed emergence at 79-91% after two weeks storage. The use of rice husk ash at 5-10 g/100 seeds after two weeks storage affected height of cacao seedling, but did not affected stem diameters, leaf numbers, root lengths, and dry weights

  8. Effect of hot vapor filtration on the characterization of bio-oil from rice husks with fast pyrolysis in a fluidized-bed reactor.

    Chen, Tianju; Wu, Ceng; Liu, Ronghou; Fei, Wenting; Liu, Shiyu


    To produce high quality bio-oil from biomass using fast pyrolysis, rice husks were pyrolyzed in a 1-5 kg/h bench-scale fluidized-bed reactor. The effect of hot vapor filtration (HVF) was investigated to filter the solid particles and bio-char. The results showed that the total bio-oil yield decreased from 41.7% to 39.5% by weight and the bio-oil had a higher water content, higher pH, and lower alkali metal content when using HVF. One hundred and twelve different chemical compounds were detected by gas chromatography-mass spectrometry (GC-MS). The molecular weight of the chemical compounds from the condenser and the EP when the cyclone was coupled with HVF in the separation system decreased compared with those from the condenser and EP when only cyclone was used.

  9. Effect of Specimen Size on the Tensile Strength Behavior of the Plastic Waste Fiber Reinforced Soil – Lime – Rice Husk Ash Mixtures

    Muntohar A.S.


    Full Text Available Improvement of tensile strength in fiber reinforced soil is an important research topic. A study has been undertaken to investigate the strength of stabilized clay-soil reinforced with randomly distributed discrete plastic waste fibers by carrying out split tensile strength test. In this study, the clay soil was stabilized with lime and rice husk ash mixtures. The main purpose of this research is to investigate the effect of specimen size to the tensile strength behavior. Testing procedure was formulated using extended ASTM C496 standard. The laboratory investigation results showed that split-tensile strength of reinforced specimens increased with increase in size. The limitations of the dataset indicate that specimen size of 70 mm in diameter is the threshold to produce reasonable representative strengths.

  10. Comparison of Kinetic Study of CTMA+ Removal of Molecular Sieve Ti-MCM-41 Synthesized with Natural and Commercial Silica

    Fontes,Maria do Socorro Braga; Melo,Dulce Maria de Araújo; Costa,Cintia de Castro; Braga,Renata Martins; Melo,Marcus Antonio de Freitas; Alves,José Antônio Barros Leal Reis


    This work aimed to determine and compare the apparent activation energy, involved in thermal decomposition of CTMA+ from the pores of Ti-MCM-41 synthesized by two different source of silica in order to evaluate their influence in the template removal. The molecular sieves Ti-MCM-41 were synthesized using rice husk ash (RHA), as alternative low cost source of silica, and commercial silica gel, obtaining two mesoporous material by hydrothermal synthesis of gel molar composition of: 1.0 CTMABr: ...

  11. Review: Agricultural Wastes as a Source of Silica Material

    Novie Permatasari


    Full Text Available Silica is the most abundant components in the earth's crust and is made by way of synthesis for use in the application of technology. Silica are generally found commercially as alkoxysilane compounds (i.e such as tetraethylorthosilicate (TEOS, sodium silicate, and tetramethylorthosilicat. However, these compounds can have a negative impact on health. Thus, further approaches to find the source of silica that is safer, cheaper, and more environmentally friendly is inevitable. However, not all summary journals are thoroughly discussed the silica sources. Further, method of isolation and application of the silica from agricultural waste is limited. This paper reported studied several sources of silica derived from agricultural waste, such as rice husk, rice straw, corn cobs, and bagasse. In addition, this paper discussed also about the method of isolation of silica from agricultural waste, and its application as a catalyst.

  12. Evaluasi karakteristik abu sekam padi dengan kitosan molekul tinggi nanopartikel sebagai bahan dentinogenesis (Characteristic evaluation of rice husk ash with chitosan high molecule nanoparticle as dentinogenesis material

    Pretty Farida Sinta Silalahi


    Full Text Available Background: Mineral trioxide aggregate (MTA and resin modified glass ionomer cement (RMGIC are the material used for indirect and direct pulp capping due to biocompatibility, but these materials have many shortcomings. Mineral trioxide aggregate contains a little amount of arsenic and has long setting time, while HEMA containing RMGIC are cytotoxic. Rice husk ash nanoparticles (RHAn is a potential source of silica. High molecular chitosan nanoparticles (HMCn can stimulate the formation of reparative dentin. Combination of these two materials is biocompatible and have good sealing ability. Purpose: This study was aimed to study RHAn + HMCn used as biomaterials for prevention of pulpodentinal complex by examined at the microstructure of dentin surfaces applied with RHAn + HMCn. Methods: Twenty-four mandibular premolar teeth extracted for orthodontic purposes, were made cavity class I preparation with 3 mm depth above the cemento-enamel junction (CEJ. Then each tooth was cut in bucco-lingual direction and each part was cut using a cervical disc bur. Samples were divided into 3 groups, group I the teeth were applied with MTA; group II the teeth were applied RMGIC; group III the teeth were apllied with RHAn + HMCn. Characterization was done by using Scanning Electron Microscopy (SEM on the interface between test material and dentin adjacent to the pulp to see surface microstructure. Results: Material microstructure of RHAn + HMCn applied to the dentine showed tags like structure which was more significant than MTA. RHAn + HMCn showed to have better sealing ability than MTA. Porosity of ASPn + HMCn was less than MTA and RMGIC. Conclusion: The study suggested that the combined RHAn + HMCn biomaterials could be used as an active biomaterial that can maintain the integrity of pulp dentinal complex.Latar belakang: Mineral trioksida agregat (MTA dan semen ionomer kaca modifikasi resin (SIKMR adalah bahan yang digunakan untuk pulp capping langsung dan tidak

  13. The Utilization of Bottom Ash Coal for Briquette Products by Adding Teak Leaves Charcoal, Coconut Shell Charcoal, and Rice Husk Charcoal

    Syafrudin Syafrudin


    Full Text Available The limitations of the availability of energy sources especially fuel oil has become a serious threat for the society. The use of coal for energy source as the replacement of fuel oil, in one hand, is very profitable, but on the other hand, will cause problem which is the coal ash residue. This coal ash is a by-product of coal combustion. This coal ash contains bottom ash. Through this observation, the bottom ash can be processed to be charcoal if added by teak leaves, coconut shell, and rice husk. Also, this observation needs to add binder materials for further processing in order to form briquette. It can be used as alternative fuel, the utilization of bottom ash and biomass will give positive impact to the environment. This observation was conducted by using compositions such as bottom ash, teak leaves, coconut shell, and rice husk. The treatment was using comparison 100%:0% ; 80%:20% ; 60%:40% ; 50%:50% ; 40%:60% ; 20%:80% ; 0%:100%. The result that the best briquette was on the composition of 20% bottom ash : 80% coconut shell. The characteristic values from that composition were moisture content of 3.45%, ash content of 17,32%, calorific value of 7.945,72 Cal/gr, compressive strength of 2,18 kg/cm2, level of CO of 105 mg/m3, and heavy metals Cu of 29,83 µg/g and  Zn 32,99 µg/g. The characteristic value from each briquette composition treatment showed that the increasing usage proportion of biomass as added material for briquette was able to increase its moisture content and calorific value. Besides, it is also able to decrease its ash content and compressive strength

  14. Análise da hidratação do arroz na parboilização Water absorption kinetics in parboiled husk rice

    Fernando Mendes Botelho


    Full Text Available O objetivo deste trabalho foi estudar o fenômeno de hidratação em grãos de arroz da variedade IRGA 424 para diferentes temperaturas. Foram utilizados grãos de arroz em casca com teor de água inicial de 0,1364 kg embebidos em água destilada nas temperaturas de 35, 45, 55 e 75 ºC. O aumento da temperatura resultou em aumento da taxa de absorção de água e o modelo de Peleg ajustou-se satisfatoriamente aos dados experimentais. O coeficiente efetivo de difusão aumentou com o aumento da temperatura variando de 0,80 a 9,18 x 10-11 m²/s. A dependência do coeficiente efetivo de difusão com a temperatura pode ser descrita pela relação de Arrhenius, apresentando, para a faixa de temperatura estudada, a energia de ativação de 33,2 kJ.mol-1.The aim of this work was to study the water uptake phenomenon during soaking of husk rice (IRGA 424 under different temperatures. Grains of husk rice with initial water content of 0.1364 (d.b. imbibed in distilled water at temperatures of 35, 45, 55, and 75 ºC were used. A temperature increase resulted in an increase in the water absorption rate. The Peleg's model fitted satisfactory to the experimental data of water absorption kinetics. The effective diffusion coefficient increased with an increase in temperature ranging from 0.80 to 9.18 x 10-11 m²/s. The dependency of the effective diffusion coefficient on temperature can be described by the Arrhenius relationship for the temperature range studied, activation energy of 33.2 kJ.mol-1.

  15. Effectiveness of Rice Husk Ash in Removal of Phenolic Compounds from Aqueous Solutions, Equilibrium and Kinetics Studies

    Majid Kermani


    Full Text Available Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: Phenols in trace quantities are usually present in the treated effluent of many wastewater-treatment plants. Phenol compounds even at low concentration can cause toxicity, health and significant taste and odor problem in drinking waters. This research focuses on understanding the sorption process and developing a cost-effective technology for the treatment of water contaminated with phenolic compounds, which are discharged into the aquatic environment from a variety of sources. In order to remove phenolic compounds from water, a new natural sorbent, rice husk ash, was developed.Materials and Methods: Removal of phenol, 2-chlorophenol and 4-chlorophenol were characterized by spectrophotometric technique at wavelengths of 269.5, 274 and 280 nm, respectively, under batch equilibrium conditions and via changing the parameters of contact time, initial pH, and initial concentration of adsorbates and dosages of sorbent. Finally, the results were analyzed by the kinetic and isotherm models.Results: in this study, the equilibrium time was found to be 240 min for full equilibration of adsorbates. Removal percent of 2-chlorophenol was lower than two others. The maximum removal of phenol, 2-CP and 4-CP was observed at an initial pH of 5. The percentage removal of these phenolic compounds increased with increasing adsorbent dose and decreasing initial concentration. In kinetics studies, correlation coefficient and ARE factor showed that the sorption of phenol (R2=0.9999, 2-chlorophenol (R2=0.9992 and 4-chlorophenol (R2=1 fitted by pseudo second order model. Isotherm studies also revealed that, Langmuirmodel for phenol (R2=0.9499, Freundlich model for 2-chlorophenol (R2=0.9659 and 4-chlorophenol (R2=0.9542 were the best choices to describe the sorption behaviors.Conclusion: Sorption process is highly dependent on the pH and it affects adsorbent surface

  16. Thermogravimetric analysis and kinetics on co-pyrolysis of coal and rice husk%煤与稻壳共热解热重分析及动力学

    严东; 周敏; 宋利强


    利用热重分析仪对长焰煤和稻壳分别单独及按不同掺混比例进行热质量损失实验研究.通过比较煤与稻壳共热解热质量损失曲线和计算得到的理论曲线发现,添加稻壳对共热解过程有促进作用,在不同的稻壳掺混比例下,共热解过程质量损失率和最大质量损失速率均较理论值有不同程度的增大,推测稻壳掺混对共热解存在促进作用,促进作用与稻壳掺混比例不成线性关系.对煤与稻壳及共热解过程进行动力学分析,获得了反应活化能和频率因子,分析计算热解动力学参数表明共热解过程存在动力学补偿效应.%The long flame coal and the rice husk were co-pyrolyzed in a thermogravimetric analyzer to investigate the pyrolysis performance of each material, as well as their mixtures. The comparison of the thermogravimetric analysis ( TGA) curves by testing and the theoretical curves by calculating shows that the adding of rice husk has a certain role in promoting co-pyrolysis process, and with the different coal/rice husk mixing ratio, the mass loss rate and the maximum mass loss rate of the co-pyrolysis process both increase in different extent compared with the theoretical values. It is speculated that there is the synergistic effect in co-pyrolysis of coal/rice husk, and the synergy has nonlinear relationship with the rice husk blend ratio. Through the kinetic analysis of he coal, the rice husk and the co-pyrolysis process, the activation energy and the frequency factor were obtained. It reveals that there is a kinetic compensation effect in the co-pyrolysis process by analysis.

  17. Preparation and Characterization of Amorphous Silica and Calcium Oxide from Agricultural Wastes

    Supachai Sompech; Thananchai Dasri; Sukhontip Thaomola


    Rice husk ash and bagasse ash were agricultural wastes that provide an abundanceof the silica (SiO2) source and the chicken eggshells and duck eggshells were important sources forcalcium oxide (CaO). Therefore, in this study the rice husk ash and bagasse ash were used as raw materials for synthesisofsilica powder,while chicken eggshells and duck eggshells were synthesized forthe calcium oxide.The results from the XRD pattern clearly showedthe structural formation of amorphous SiO2 and CaO pha...

  18. 掺入稻壳灰的泡沫混凝土及其发展分析%Foam Concrete Mixed with Rice Husk Ash and its Development Analysis

    杨康; 王德玲; 喻成成; 李书磊; 王贤根


    This paper firstly introduced the development, performance and application of foam concrete. Secondly the property of rice husk ash ( RHA) was discussed. RHA con_tains about 90% amorphous silica which has high pozzolanic ac_tivity. Thirdly the effect of RHA on foam concrete was dis_cussed. RHA can enhance the strength of foam concrete in later age and improve its durability, homogeneity and corrosion resist_ance. It also improves the pore structure of foam concrete, ther_mal insulation and sound absorption performance. Lastly, the development of foam concrete mixed with RHA was analyzed from following aspects: selecting and processing materials such as foa_ming agents, RHA and cement, improving producing process of foam concrete, reducing cost and environmental impact.%本文先介绍了泡沫混凝土的发展、性能与应用,然后介绍了稻壳灰的性质,稻壳灰中含有90%左右的无定形态的二氧化硅,具有火山灰活性;接着讨论了稻壳灰替代部分水泥对泡沫混凝土性质的影响。稻壳灰可增强泡沫混凝土的后期强度和抗渗、耐侵蚀性,改善泡沫混凝土的孔隙结构,增强保温隔热、隔音性。最后对掺入稻壳灰的泡沫混凝土的发展方向进行了分析,包括选择和处理材料如发泡剂、稻壳灰、水泥等;优化生产工艺;降低成本及减小环境影响。

  19. Synthesis and characterisation of composite based biohydroxyapatite bovine bone mandible waste (BHAp) doped with 10 wt % amorphous SiO{sub 2} from rice husk by solid state reaction

    Asmi, Dwi, E-mail:, E-mail:; Sulaiman, Ahmad, E-mail:; Oktavia, Irene Lucky, E-mail: [Department of Physics, Faculty of Mathematics and Natural Sciences, University of Lampung Jl. Sumantri Brojonegoro No.1 Gedung Meneng Bandar Lampung 35145 (Indonesia); Badaruddin, Muhammad, E-mail: [Department of Mechanical Engineering, Faculty of Engineering, University of Lampung Jl. Sumantri Brojonegoro No.1 Gedung Meneng Bandar Lampung 35145 (Indonesia); Zulfia, Anne, E-mail: [Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Indonesia, Kampus Baru-UI, Depok 16424 (Indonesia)


    Effect of 10 wt% amorphous SiO{sub 2} from rice husk addition on the microstructures of biohydroxyapatite (BHAp) obtained from bovine bone was synthesized by solid state reaction. In this study, biohydroxyapatite powder was obtained from bovine bone mandible waste heat treated at 800 °C for 5 h and amorphous SiO{sub 2} powder was extracted from citric acid leaching of rice husk followed by combustion at 700°C for 5 h. The composite powder then mixed and sintered at 1200 °C for 3 h. X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM) techniques are utilized to characterize the phase relations, functional group present and morphology of the sample. The study has revealed that the processing procedures played an important role in microstructural development of BHAp-10 wt% SiO{sub 2} composite. The XRD study of the raw material revealed that the primary phase material in the heat treated of bovine bone mandible waste is hydroxyapatite and in the combustion of rice husk is amorphous SiO{sub 2}. However, in the composite the hydroxyapatite, β-tricalcium phosphate, and calcium phosphate silicate were observed. The FTIR result show that the hydroxyl stretching band in the composite decrease compared with those of hydroxyapatite spectra and the evolution of morphology was occurred in the composite.

  20. On Technique of Preparing Silicon-Iron-Peach by Using Rice Husk Ash%稻壳灰制备硅铁红的工艺研究

    章慧芳; 蔡景清; 蔡新安; 刘文茂; 裴剑锋


    [目的]研究了稻壳灰制备硅铁红的工艺,为拓宽稻壳灰综合利用途径提供参考.[方法]在微波辐射条件下,采用稻壳灰为原料制备水玻璃,而后以此水玻璃为原料,利用溶胶-凝胶法,在微波辅助干燥条件下制备硅铁红颜料.同时考查了硅/铁摩尔比、微波辐射功率及时间、煅烧温度等因素对硅铁红包裹率的影响.[结果]研究表明,硅/铁摩尔比为7∶1,微波辐射功率和时间分别为600W和8min,前驱体煅烧温度和时间分别为750℃和2h;此条件下制备的Fe2O3/SiO2,其包裹率达到93.1%.[结论]在微波辅助下通过简单的sol-gel工艺,可以将SiO2玻璃包裹于Fe2O3颗粒表面而制备出硅铁红包裹颜料并且所制备的硅铁红包裹率高达93%左右,比市售硅铁红的包裹率要高.该工艺操作简单,适合工业化生产.%[Objective] The method for the preparation of the silicon-iron-peach (Fe2O3/SiO2) ceramic pigment by using the rice husk ash was studied,and it is hoped for supplying a new route to broaden the comprehensive utilization of the rice husk ash.[Method] Firstly,the rice husk ash was used for the preparation of the sodium silicate,and then the obtained sodium silicate were used as the raw materials for the sol-gel synthesis of the Fe2O3/SiO2 powders.In this process,microwave was used for the drying of the Fe2O3/SiO2 powders.The effects of the mol ratio of Fe/Si,time and powder of microwave irradiation,and the sintering temperature on encapsulation rate of Fe2O3/SiO2 were studied.[Result] The optimal parameters for the synthesis of Fe2O3/SiO2 were listed as follows:the mol ratio of Fe/Si is 7∶ 1,then microwave radiated for 8 min with a power of 600 W,subsequently,sintered at 750 ℃ for 2 h to obtain Fe2O3/SiO2 ceramic pigment.The results indicated that the encapsulation rate of Fe2O3/SiO2 can reach 93.1%.[Conclusion] The method is easy to operate,and the encapsulation rate of the Fe2O3/SiO2 powders is more excellent

  1. Component Analysis, Inhibitory and Germicidal Performances of Rice Husk Vinegar%稻壳醋液的成分分析及抑菌、杀菌性能研究

    周建斌; 迟菲; 秦恒飞


    Rice husk vinegar fluid was prepared using the rice husk as raw material, and the main component was analyzed by the gas chromatography-mass spectrum, The inhibitory and germicidal performances of rice husk vinegar fluid toward the representative strains in the eumycetes and bacterium classes under different dilution ratio were studied. 39 Kinds of organic components were identified from the rice husk vinegar fluid, its principal constituents contain phenols, acids, ketones, alcohols. esters. aldehydes etc.. Inhibitory performance test results show that under the condition of action for 8 min, using the dilution ratio 1∶ 2, 1∶1. 1∶2 and 1∶1 respectively, the rice husk vinegar can respectively have 100 % inhibitory rate to word Aspergillus niger, Candinda albicans. E scherichia coli and Staphylococcus, aureus. Germicidal performance test results show that under the,condition of affecting 8 min, at the dilution ratio of 1∶1. the rice husk vinegar can have 100 % germicidal rate toward the four indicated bacteria. At the dilution ratio of 1∶3, 1∶2 and 1∶3, the rice busk vinegar can respectively have 91.5%、92.5%、92.2% sterilization tate toward A. niger. C. albicans and E. coli. The rice husk vinegar fluid has strong inhibitory and germicidal performances.%以稻壳为原料制备稻壳醋液,采用气-质联用仪分析了稻壳醋液的主要化学成分,并研究了不同稀释比的稻壳醋液对真菌类和细菌类中有代表性菌株的抑菌和杀菌性能.试验从稻壳醋液中鉴定出39种有机组分,其主要成分为酚类、酸类、酮类、醇类、酯类、醛类及其它组分.抑菌性能测试试验表明稻壳醋液有较好的抑菌作用.在作用8 min的条件下,醋液-水稀释比为1∶2,1∶1,1∶2,1∶1(体积比,下同)的稻壳醋液分别对黑曲霉菌、白色念珠菌、大肠杆菌、金黄色葡萄球菌达到100%的抑菌率.杀菌性能研究试验表明稻壳醋液有较好的杀菌

  2. Utilização de casca de arroz e esterco bovino como substrato Eisenia fetida Savigny (1826 Rice husk and cattle manure used as substrate for the Eisenia fetida Savigny (1826 multiplication

    Zaida Inês Antoniolli


    Full Text Available A utilização de minhocas, principalmente para a alimentação animal, vem sendo adotada e estudada, pois esses organismos apresentam em sua constituição vitaminas e aminoácidos. Entre os materiais possíveis de serem utilizados na minhocultura, atualmente incentiva-se o aproveitamento de resíduos agroindustriais de alta disponibilidade, como a casca de arroz no Rio Grande do Sul. Objetivou-se, neste trabalho, avaliar a eficiência de substratos à base de casca de arroz e esterco bovino na multiplicação e produção de biomassa de minhocas (Eisenia fetida. A população de minhocas foi avaliada quanto ao número de cocons, ao índice de multiplicação (população final/população inicial e à biomassa de minhocas frescas e secas. A avaliação foi realizada aos 60 dias após a instalação do experimento, com quatro repetições. A análise estatística dos resultados mostrou que a inclusão de casca de arroz favoreceu o desenvolvimento e a taxa de reprodução das minhocas. A maior biomassa de minhocas foi obtida nos tratamentos: 50% casca de arroz inteira e 50% esterco bovino, esterco bovino mais casca de arroz inteira tratada com hidróxido de amônio a 20 e 40%, e esterco bovino mais casca de arroz moída tratada com hidróxido de sódio a 10 e 40%. Conclui-se que a adição de casca de arroz ao esterco bovino favorece a multiplicação e o desenvolvimento de E. fetida.The use of earthworms for animal feeding has been adopted and studied, because these organisms are rich in vitamins and essential amino acids. Among the organic materials that could be used in the earthworm breeding, highly available agroindustrial residues such as rice husk are being currently used in Rio Grande do Sul. The aim of this work was to evaluate substrate based on rice husk and cattle manure on the multiplication and biomass of earthworms (Eisenia fetida. In this work, the population of earthworms, the cocoon numbers, the multiplication index, as well as

  3. Preparation of activated carbon from carbonized rice husk by ozone activation for Cr(VI) removal%炭化米糠经臭氧活化制备活性炭及其去除Cr(VI)离子

    Sivaraju Sugashini


    以臭氧为活化剂,炭化的米糠为原料制备出活性炭。采用氮吸附、SEM-EDAX 和FT-IR对样品进行表征。活性炭的比表面积由活化前的20 m2/g增加到380 m2/g。在臭氧活化过程中,吸附在炭材料上的二氧化硅变疏松,从而导致碳逸出。臭氧同时以氧分子和原子形式存在于炭表面。氧原子,作为强氧化剂,将炭表面氧化成酸性官能团如羧基、酮基和酚基。采用该活性炭吸附Cr (VI)离子,Cr (VI)离子的最大去除率(94%)的条件为:pH值2.0、浓度100 mg/L、吸附量0.2 g,时间2.5 h及转速300 r/min。采用吸附平衡和动力学模型探讨吸附机理,结果表明,吸附等温线符合Freundlich方程,吸附速率符合准二级动力学方程。吸附是自发的放热反应,可能与NaOH脱落而恢复Cr和碳有关。%Activated carbon ( AC) was prepared from carbonized rice husks using ozone as an activating agent. The AC was char-acterized by nitrogen adsorption, SEM-EDAX and FT-IR. The Brunauer-Emmett-Teller surface area of the carbons was increased from 20 to 380 m2/g by the activation. It was observed that the silica attached to the carbonaceous material is loosened, leading to a release of carbon during the ozone activation. Ozone exists as both molecular and atomic oxygen on the surface of carbon. Atomic oxygen, as a powerful oxidizing agent, oxidizes the carbon surface into acidic functional groups such as carboxylic, ketonic and phenolic. The rice husk AC was used for the adsorption of Cr (VI) ions. A maximum removal percentage (94%) of Cr (VI) ions was obtained for a 100 mg/L aqueous solution at the optimized conditions of pH value of 2. 0, adsorbent dosage of 0. 2 g, time of 2. 5 h and stirring speed of 300 r/min. Adsorption equilibrium and kinetic models were used to investigate the adsorption mecha-nism. It was found that the adsorption isotherms were well fitted by the Freundlich equation. The adsorption rate follows pseudo sec-ond order kinetics

  4. Study on the effects of white rice husk ash and fibrous materials additions on some properties of fiber-cement composites.

    Hamzeh, Yahya; Ziabari, Kamran Pourhooshyar; Torkaman, Javad; Ashori, Alireza; Jafari, Mohammad


    This work assesses the effects of white rice husk ash (WRHA) as pozzolanic material, virgin kraft pulp (VKP), old corrugated container (OCC) and fibers derived from fiberboard (FFB) as reinforcing agents on some properties of blended cement composites. In the sample preparation, composites were manufactured using fiber-to-cement ratio of 25:75 by weight and 5% CaCl(2) as accelerator. Type II Portland cement was replaced by WRHA at 0%, 25% and 50% by weight of binder. A water-to-binder ratio of 0.55 was used for all blended cement paste mixes. For parametric study, compressive strength, water absorption and density of the composite samples were evaluated. Results showed that WRHA can be applied as a pozzolanic material to cement and also improved resistance to water absorption. However, increasing the replacement level of WRHA tends to reduce the compressive strength due to the low binding ability. The optimum replacement level of WRHA in mortar was 25% by weight of binder; this replacement percentage resulted in better compressive strengths and water absorption. OCC fiber is shown to be superior to VKF and FFB fibers in increasing the compressive strength, due to its superior strength properties. As expected, the increase of the WRHA content induced the reduction of bulk density of the cement composites. Statistical analysis showed that the interaction of above-mentioned variable parameters was significant on the mechanical and physical properties at 1% confidence level.

  5. Pressurized pyrolysis of rice husk in an inert gas sweeping fixed-bed reactor with a focus on bio-oil deoxygenation.

    Qian, Yangyang; Zhang, Jie; Wang, Jie


    The pyrolysis of rice husk was conducted in a fixed-bed reactor with a sweeping nitrogen gas to investigate the effects of pressure on the pyrolytic behaviors. The release rates of main gases during the pyrolysis, the distributions of four products (char, bio-oil, water and gas), the elemental compositions of char, bio-oil and gas, and the typical compounds in bio-oil were determined. It was found that the elevation of pressure from 0.1MPa to 5.0MPa facilitated the dehydration and decarboxylation of bio-oil, and the bio-oils obtained under the elevated pressures had significantly less oxygen and higher calorific value than those obtained under atmospheric pressure. The former bio-oils embraced more acetic acid, phenols and guaiacols. The elevation of pressure increased the formation of CH4 partially via the gas-phase reactions. An attempt is made in this study to clarify "the pure pressure effect" and "the combined effect with residence time".

  6. Rice husk based porous carbon loaded with silver nanoparticles by a simple and cost-effective approach and their antibacterial activity.

    Cui, Jianghu; Yang, Yunhua; Hu, Yonghui; Li, Fangbai


    In this paper, we chose rice husk as raw material and synthesized successfully porous carbon loaded with silver nanoparticles (RH-Ag) composites by simple and cost-effective method. The as-prepared RH-Ag composites have a BET-specific surface area of 1996 m(2) g(-1) and result in strong capacity of bacteria adsorption. The result of antibacterial study indicated that the RH-Ag system displayed antibacterial activity that was two times better than pure Ag NPs. Our study demonstrates that the antibacterial activity of RH-Ag composites may be attributed to their strong adsorption ability with bacteria and result in the disorganization of the bacterial membrane ultrastructure. In addition, RH-Ag system was found to be durative slow-releasing of silver ions and biocompatible for human skin keratinocytes cells. In terms of these advantages, the RH-Ag composites have potential application in antibacterial infections and therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Extraction of nano-silicon with activated carbons simultaneously from rice husk and their synergistic catalytic effect in counter electrodes of dye-sensitized solar cells

    Ahmad, Waqar; Bahrani, Majid Raissan Al; Yang, Zhichun; Khan, Jahangeer; Jing, Wenkui; Jiang, Fan; Chu, Liang; Liu, Nishuang; Li, Luying; Gao, Yihua


    The extraction of renewable energy resources particularly from earth abundant materials has always been a matter of significance in industrial products. Herein, we report a novel simultaneous extraction of nano-silicon with activated carbons (nano-Si@ACs) from rice husk (RH) by chemical activation method. As-extracted nano-Si@ACs is then used as an energy harvesting materials in counter electrodes (CEs) of dye-sensitized solar cells (DSSCs). The morphology, structure and texture studies confirm the high surface area, abundant active sites and porous structure of nano-Si@ACs. Electrochemical impedance spectroscopy and cyclic voltammetry analyses reveal that the nano-Si@ACs is highly beneficial for fast I3‑ reduction and superior electrolyte diffusion capability. The nano-Si@ACs CE based DSSC exhibits enhanced power conversion efficiency of (8.01%) in contrast to pristine Pt CE (7.20%). These favorable results highlight the potential application of RH in low-cost, high-efficiency and Pt-free DSSCs.

  8. Microstructural characteristics, mechanical and wear behaviour of aluminium matrix hybrid composites reinforced with alumina, rice husk ash and graphite

    Kenneth Kanayo Alaneme


    Full Text Available The microstructural characteristics, mechanical and wear behaviour of Aluminium matrix hybrid composites reinforced with alumina, rice husk ash (RHA and graphite were investigated. Alumina, RHA and graphite mixed in varied weight ratios were utilized to prepare 10 wt% hybrid reinforced Al-Mg-Si alloy based composites using two-step stir casting. Hardness, tensile properties, scanning electron microscopy, and wear tests were used to characterize the composites produced. The results show that Hardness decreases with increase in the weight ratio of RHA and graphite in the composites; and with RHA content greater than 50%, the effect of graphite on the hardness becomes less significant. The tensile strength for the composites containing o.5wt% graphite and up to 50% RHA was observed to be higher than that of the composites without graphite. The toughness values for the composites containing 0.5wt% graphite were in all cases higher than that of the composites without graphite. The % Elongation for all composites produced was within the range of 10–13% and the values were invariant to the RHA and graphite content. The tensile fracture surface morphology in all the composites produced was identical characterized with the presence of reinforcing particles housed in ductile dimples. The composites without graphite exhibited greater wear susceptibility in comparison to the composite grades containing graphite. However the wear resistance decreased with increase in the graphite content from 0.5 to 1.5 wt%.

  9. Microstructure and mechanical behavior of stir-cast Zn–27Al based composites reinforced with rice husk ash, silicon carbide, and graphite

    Kenneth Kanayo Alaneme


    Full Text Available The microstructure and mechanical properties of Zn–27Al based composites reinforced with rice husk ash (RHA, silicon carbide (SiC, and graphite (Cg particles have been investigated. The Zn–27Al composites consisting of varied weight ratios of the reinforcing materials were produced using the stir casting process. Hardness test, tensile properties evaluation, fracture toughness determination, and microstructural examination, were used to characterize the composites produced. Results show that the microstructures of the composites are similar, consisting of the dendritic structure of the Zn–27Al alloy matrix with fine dispersion of the reinforcing particles. The hardness of the composites decreased with increase in the weight percent of RHA (and corresponding decrease in SiC weight percent in the reinforcement. The tensile strength and yield strength decreased slightly with increase in the weight ratio of RHA in the composites with a maximum of 8.5% and 9.6% reductions respectively observed for as much as 40% RHA (corresponding to 40% reduction in SiC in the hybrid reinforcement. Although some of the composite compositions containing RHA had slightly higher % elongation values compared with those without RHA, it was generally observed that the % elongation was invariant to the composite RHA content. The fracture toughness of the composites increases with increase in the weight percent of RHA with as much as a 20% increase obtained for as much as 40% RHA (corresponding to 40% reduction in SiC in the hybrid reinforcement.

  10. Assessment of Concrete Strength Using Partial Replacement of Coarse Aggregate for Wast Tiles and Cement for Rice Husk Ash in Concrete

    Umapathy U


    Full Text Available Conservation of natural resources and preservation of environment is the essence of any development. The problem arising from continuous technological and industrial development is the disposal of waste material. If some of the waste materials are found suitable in concrete making, not only cost of construction can be cut down, but also safe disposal of waste materials can be achieved. So in our project, an attempt has been made to assess the suitability of stone with waste tills in concrete making. In the laboratory tiles has been tried as coarse aggregate has been used as partial substitute to conventional coarse aggregate concrete making and today many researches are ongoing into the use of Portland cement replacements, using many waste materials like pulverized fly ash (PFA and ground granulated blast furnace slag (GGBS. Like PFA and GGBS a waste glass powder (GLP is also used as a binder with partial replacement of cement which takes some part of reaction at the time of hydration. In this study, rice husk ash have been used as partially replacements to the cement Cubes were cast and tested for compressive strength, and modulus of rupture after a curing period of 7,17,28 days.

  11. Preparation and characterization activated carbon from rice husk and oil palm empty fruit bunches for removal of Zn2+ in aqueous solution

    Ismail, Nur Enzati Afwana; Taha, Mohd F.; Ramli, Anita


    The ability of activated carbon prepared from rice husk (RH), oil palm empty fruit bunches (EFB) and mixture (Mix) activated carbon in adsorption of Zinc (Zn2+) from aqueous solution was investigated. The Mix activated carbon has prepared from mixture of RH and EFB activated carbon with weight ratio (1:1) The RH and EFB activated carbon were produced by using sodium hydroxide (NaOH) as a dehydrating agent in chemical activation process.EFB activated carbon showed excellent efficiency in removing Zn2+ with their percentage removal up to 100% even at low adsorbent dosage. The study also showed that the adsorption of Zn2+ by EFB, RH and Mix activated carbon is dependent on the adsorbent dosage and initial metal concentration. The adsorption isotherms of the Zn2+ of EFB, RH and Mix activated carbon were determined and compared with Langmuir and Freundlich models. It was showed that Langmuir model was more favorable for RH and Mix activated carbon with correlation coefficient (R2) value is 0.9958 and 0.9847. In contrast, EFB activated carbon was more favorable to the Freundlich and Langmuir model with correlation coefficient (R2) are 0.9967 and 0.9967

  12. Fabrication and Mechanical Properties of SiCw(p/SiC-Si Composites by Liquid Si Infiltration using Pyrolysed Rice Husks and SiC Powders as Precursors

    Dan Zhu


    Full Text Available Dense silicon carbide (SiC matrix composites with SiC whiskers and particles as reinforcement were prepared by infiltrating molten Si at 1550 °C into porous preforms composed of pyrolysed rice husks (RHs and extra added SiC powder in different ratios. The Vickers hardness of the composites showed an increase from 18.6 to 21.3 GPa when the amount of SiC added in the preforms was 20% (w/w, and then decreased to 17.3 GPa with the increase of SiC added in the preforms up to 80% (w/w. The values of flexural strength of the composites initially decreased when 20% (w/w SiC was added in the preform and then increased to 587 MPa when the SiC concentration reached 80% (w/w. The refinement of SiC particle sizes and the improvement of the microstructure in particle distribution of the composites due to the addition of external SiC played an effective role in improving the mechanical properties of the composites.

  13. Microsized Porous SiOx@C Composites Synthesized through Aluminothermic Reduction from Rice Husks and Used as Anode for Lithium-Ion Batteries.

    Cui, Jinlong; Cui, Yongfu; Li, Shaohui; Sun, Hongliang; Wen, Zhongsheng; Sun, Juncai


    Microsized porous SiOx@C composites used as anode for lithium-ion batteries (LIBs) are synthesized from rice husks (RHs) through low-temperature (700 °C) aluminothermic reduction. The resulting SiOx@C composite shows mesoporous irregular particle morphology with a high specific surface area of 597.06 m(2)/g under the optimized reduction time. This porous SiOx@C composite is constructed by SiOx nanoparticles uniformly dispersed in the C matrix. When tested as anode material for LIBs, it displays considerable specific capacity (1230 mAh/g at a current density of 0.1 A/g) and excellent cyclic stability with capacity fading of less than 0.5% after 200 cycles at 0.8 A/g. The dramatic volume change for the Si anode during lithium-ion (Li(+)) insertion and extraction can be successfully buffered because of the formation of Li2O and Li4SiO4 during initial lithiation process and carbon coating layer on the surface of SiOx. The porous structure could also mitigate the volume change and mechanical strains and shorten the Li(+) diffusion path length. These characteristics improve the cyclic stability of the electrode. This low-cost and environment-friendly SiOx@C composite anode material exhibits great potential as an alternative for traditional graphite anodes.

  14. Properties of Bio-oil from Fast Pyrolysis of Rice Husk%稻壳快速热裂解生物油的特性研究

    郭秀娟; 王树荣; 王琦; 郭祚刚; 骆仲泱


    Physicochemical properties of bio-oil obtained from fast pyrolysis of rice husk were studied in the present work. Molecular distillation was used to separate the crude bio-oil into three fractions viz. light fraction, middle fraction and heavy fraction. Their chemical composition was analyzed by gas chromatograph and mass spectrometer (GC-MS). The thermal behavior, including evaporation and decomposition, was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FT1R). The product distribution was significantly affected by contents of cellulose, hemicellulose and lignin. The bio-oil yield was 46.36% (by mass) and the yield of gaseous products was 27% (by mass). The chemicals in the bio-oil included acids, aldehydes, ketones, alcohols, phenols, sugars, etc. The light fraction was mainly composed of acids and compounds with lower boiling point temperature, the middle and heavy fractions were consisted of phenols and levoglucosan. The thermal stability of the bio-oil was determined by the interactions and intersolubility of compounds. It was found that the thermal stability of bio-oil was better than the light fraction, but worse than the middle and heavy fractions.

  15. H-ZSM-5 Zeolite Synthesis by Sourcing Silica from the Wheat Husk Ash: Characterization and Application as a Versatile Heterogeneous Catalyst in Organic Transformations including Some Multicomponent Reactions

    Isak Rajjak Shaikh


    Full Text Available ZSM-5 zeolite was synthesized by sourcing silica from wheat husk ash and was converted into its protonated form following careful, conventionally accepted ion-exchange method and calcinations. The H-ZSM-5 zeolite (Si/Al ratio = 30 prepared was appropriately characterized by XRD, FT-IR, SEM, TEM, TG-DTA, CV, and so forth, and evaluated as recyclable catalyst in selective organic transformations including three- and four-component reactions. The catalytic activity of the zeolite sample supposedly relates to increased density of the accessible acid sites.

  16. In vitro simulation studies of silica deposition induced by lignin from rice


    To reveal the possible mechanism of silica deposition in higher plants, lignin was isolated from rice straw following a modified method to conduct a simulation experiment in vitro. UV and infrared absorption spectra showed that the substance had the unique characteristics of pure lignin. The presence of silicon in the precipitation was revealed by TEM (transmission electron microscopy) with EDXA (energy dispersive X-ray analysis) device. It was found that in the borax solution where lignin precipitation occurred silica-lignin co-precipitation was produced but not in the DMSO solution where lignin was broken into its composition compounds and did not precipitate. This means that it is macromolecular lignin itself but not its compounds that could induce silica deposition in higher plants.

  17. Research of Dislodgment of Ferric Ion Using Modified Rice Husk%改性米糠去除铁离子的研究



    Using Rice bran as a raw material, after 30rain treatment of a 5% potassium hydroxide solution to boil soak, it becomes a pH≤3.3, the surface area 13m2 / g, the macropore volume of 35.5 ml / g silica precipitation adsorbent i.e. modified rice bran. This paper studied the best condition of using this modified rice bran to remove iron ion in the recovered phosphoric acid solution. Experiment result showed that at room temperature, 3g of the modified rice bran contacted with the iron ions in the phosphoric liquid 24h, filtered, then the purpose of the removal of iron is achieved, the efficiency of this method is up to 90%.This method is a worthy application technology.%以米糠为原料,用5%氢氧化钾液煮沸浸泡30min处理后,形成pH小于3.3,比表面积13m2/g,大孔体积35.5mL/g二氧化硅沉淀吸附剂即改性米糠。本文研究了利用该改性米糠去除回收磷酸液中铁离子的最佳条件。实验结果表明:在常温下,改性米糠3g与磷酸液中的铁离子接触24h,过滤,即可达到除铁的目的,用此法除铁离子效果可达90%,是一种值得推广的应用技术。

  18. Synthesis and characterization of chitosan-graft-poly(acrylic acid)/rice husk ash hydrogels composites; Sintese e caracterizacao de hidrogeis compositos de cinza da casca de arroz e quitosana enxertada com poli(acido acrilico)

    Rodrigues, Francisco H.A. [Universidade Estadual Vale do Acarau - UVA, Sobral, CE (Brazil); Lopes, Gabriel V.; Pereira, Antonio G.B.; Fajardo, Andre R.; Muniz, Edvani C. [Universidade Estadual de Maringa - UEM, PR (Brazil)


    According to environmental concerns, super absorbent hydrogel composites were synthesized based on rice husk ash (RHA), an industrial waste, and Chitosan-graft-poly(acrylic acid). The WAXS and FTIR data confirmed the syntheses of hydrogel composites. The effect of crystalline or amorphous RHA on water uptake was investigated. It was found that the RHA in crystalline form induces higher water capacity (W{sub eq}) of composites hydrogels due to the fact that the intra-interactions among silanol groups on RHA make available new sites in the polymer matrix, which could interact to water. (author)

  19. Research on Microbial Inoculation for Composting of Rice Husks%稻壳基质化腐熟处理微生物菌剂添加量的研究

    尚秀华; 谢耀坚; 张沛健; 林国祚; 彭彦


    以稻壳为研究对象,采用单因素试验设计,菌剂添加量为稻壳干物质重量的1%、2%、3%、5%、7%、9%,对稻壳基质化腐熟处理微生物菌剂最适添加量进行研究。结果表明:添加微生物菌剂越多,物料堆体温度达到最高温度的速度越快,但维持的高温时间较短,添加1%菌剂稻壳达到温度最高,为52℃,且高温过程维持时间较长;菌剂不同添加量对稻壳有机质含量、C/N比影响不大,均达到腐熟标准;从基质理化性质、育苗效果及生产成本综合考虑,添加干物质量l%菌剂腐熟效果最好,大规模生产中添加量可减少。%In order to find the best rate of microbial inoculant to facilitate composfing of rice husks, a single factor experimental trial was conducted. This involved treatments of adding inoculant to rice husk at rates of 1%, 2%, 3%, 5%, 7% and 9% of dry weight. The results showed that higher amounts of microbial inocu- lant resulted in higher temperatures during composting and the peak temperature was reached faster, but the duration of the peak temperature was shorter. In contrast, with addition of just 1% microbial inoculant, the maximum temperature was 52 ~C and this temperature was maintained for a long time. The organic matter con- tent and C/N ratio of the rice husk did not seem to influence the optimal amount of microbial inoculant. It was concluded that adding microbial inoculants at the rate of 1% of rice husk dry weight was optimal based on a criteria matrix that included physicochemical properties of the compost, subsequent effects on seedling growth and production cost. It also appeared that the rate of inoculant could well be reduced below the 1% level for mass media production.

  20. 电厂废弃稻壳灰水热合成ZSM-5分子筛%Hydrothermal synthesis of ZSM-5 zeolite from rice husk ash in power plant

    张超; 郎林; 阴秀丽; 吴创之


    The rice husk ash collected from biomass power plants was reacted with KOH solution to obtain silica sol, which was used to synthesize ZSM-5 zeolite by hydrothermal crystallization. The effects of KOH solution concentration, reaction temperature, and reaction time on the Si dissolving rate were investigated, and the optimum parameters of alkali dissolution were obtained. The effects of template contentrations and Si/Al molar ratio on the synthesis of ZSM -5 zeolite in the complex system were also studied. The as-synthesized samples were characterized by XRD, SEM, ICP, TG-DSC and BET. The results show that the ZSM-5 crystals could be successfully synthesized in a wide range of the Si/Al molar ratio (15~2002), and the products (30≤Si/Al≤52002)had complete crystal shape, high thermal stability, large specific surface area, and its micropore size was centered at about 0.53 nm.%以电厂废弃稻壳灰为原料,通过KOH溶液水热处理制取硅溶胶,采用水热合成法制备ZSM-5分子筛.考察了KOH溶液浓度、反应温度和反应时间对Si溶出率的影响,探索出最佳碱溶工艺条件;研究了在复杂合成体系中,模板剂用量、Si/Al等因素对ZSM-5分子筛合成过程的影响;采用XRD,SEM,ICP,TG-DSC,N2吸附脱附等手段进行表征,结果表明,以电厂废弃稻壳灰为原料,在较宽Si/Al范围内(15~2002)均可合成出ZSM-5分子筛;当Si/Al为30~2002时,分子筛产物晶形较为完备,热稳定性好,比表面积较大,微孔分布集中于0.53 nm.


    Marcela Villalba Cadavid


    Full Text Available En este estudio se empleó cascarilla de arroz como materia prima para la obtención de xilitol, previa hidrólisis durante 60 minutos con ácido sulfúrico al 4% p/v; a 121 ºC y 15 psig,; La xilosa producida se transformó en xilitol mediante su fermentación con Candida guilliermondii. Se estudió el efecto de las variables concentración inicial de xilosa, concentración de inóculo y relación volumen del medio/volumen del matraz, así como sus efectos combinados, sobre la producción de xilitol. Se encontró que las concentraciones iniciales de xilosa e inóculo más adecuadas, entre los valores ensayados, fueron 80 y 5,0 g/l, respectivamente. En estas condiciones, la concentración final de xilitol obtenida fue de 45,2 g/l, con una productividad volumétrica de 0,23 g/l•h y un rendimiento de 0,57 g/g.In this study was used rice husk, previosly hydrolyzed with diluted sulfuric acid at 121 ºC and 15 psig, with a residence time 60 min. The initial concentration of substrate, inoculum, and relationship between media volume/flask volume and their combined effects were studied on the production of xylitol. The initial concentrations of 80 g/l xylose and 5 g/l inoculums led the best xylitol production (45.2 g/l, productivity (0.23 g/l•h and yield (0.57 g/g.

  2. Corrosion and wear behaviour of Al–Mg–Si alloy matrix hybrid composites reinforced with rice husk ash and silicon carbide

    Kenneth Kanayo Alaneme


    Full Text Available The corrosion and wear behaviour of Al–Mg–Si alloy matrix hybrid composites developed with the use of rice husk ash (RHA and silicon carbide (SiC particulates as reinforcements were investigated. RHA and SiC mixed in weight ratios 0:1, 1:3, 1:1, 3:1, and 1:0 were utilized to prepare 5, 7.5 and 10 wt% of the reinforcing phase with Al Mg Si alloy as matrix using double stir casting process. Open circuit corrosion potential (OCP and potentiodynamic polarization measurements were used to study the corrosion behaviour while coefficient of friction was used to assess the wear behaviour of the composites. The corrosion and wear mechanisms were established with the aid of scanning electron microscopy. The results show that the effect of RHA/SiC weight ratio on the corrosion behaviour of the composites in 3.5% NaCl solution was not consistent for the different weight percent of reinforcement (5, 7.5, and 10 wt% used in developing the Al–Mg–Si based composites. It was evident that for most cases the use of hybrid reinforcement of RHA and SiC resulted in improved corrosion resistance of the composites in 3.5% NaCl solution. Preferential dissolution of the more anodic Al–Mg–Si alloy matrix around the Al–Mg–Si matrix/RHA/SiC particle interfaces was identified as the primary corrosion mechanism. The coefficient of friction and consequently the wear resistance of the hybrid composites were comparable to that of the Al–Mg–Si alloy matrix reinforced with only SiC.

  3. Comparison of rice husk- and dairy manure-derived biochars for simultaneously removing heavy metals from aqueous solutions: role of mineral components in biochars.

    Xu, Xiaoyun; Cao, Xinde; Zhao, Ling


    Rice husk biochar (RHBC) and dairy manure biochar (DMBC) were prepared as sorbents for simultaneously removing Pb, Cu, Zn, and Cd from aqueous solutions. DMBC was more effective in removing all the four heavy metals than RHBC, with the removal capacities of above 486 mmol kg(-1) for each metal, much higher than those of RHBC (65.5-140 mmol kg(-1)). RHBC showed stronger competition for metal removal than DMBC when the four metals coexisted, with Pb the least affected and Cd the most inhibited. When each metal was 1mM in the multi-metal system, the metal removal by RHBC was reduced by 38.4-100%, much higher than that reduced by 2-40.9% for DMBC. The stronger competition for metals removal by RHBC was due to the fact that all metals competed only for the ionized phenolic-O(-) groups, while the removal of metals by DMBC resulted not only from the complexation with ionized hydroxyl-O(-) groups but also from the precipitation of metals with CO3(2-) and/or PO4(3-) that were rich in DMBC, resulting in less competition. The different mechanisms for the removal of metals by the two biochars were evidenced by the instrumental analysis of XRD, FTIR, and SEM as well as chemical modeling of Visual MINTEQ. Results indicated the waste biomass can be converted into value-added biochar as sorbents for removal of heavy metals and the removal ability varies with different biochar feedstock sources where the mineral components such as CO3(2-), PO4(3-) originated from the feedstock play an important role in the sorption nature of biochar.

  4. Preparation and Mechanical Properties of Disposable Dishes Based on Rice Husk Powder%稻壳粉一次性餐盘的制备及力学性能研究

    李娟; 王洪江; 孟令伟; 刘伟; 李晨阳; 王艳


    A kind of biodegradable disposable dishes were prepared by cold-press approach with rice husk powder as a substrate,salad oil as a release agent,xanthan gum and sodium carboxymethyl cellulose as a bind-er.Modulus of rupture and weight-bearing of dishes were investigated.Orthogonal test results showed that the optimal combination of mechanical properties of the recipe is rice husk powder 159.25g (91%w/w),xanthan gum 7.00g (5% w/w),sodium carboxymethyl cellulose 8.75g (4 % w/w).%以稻壳粉作为基材,以色拉油为脱模剂,并以黄原胶和羧甲基纤维素钠作为粘合剂,用冷压法制备一次性可降解的餐盘,并且对其静曲强度和负重性进行了检测。正交试验结果表明,最优力学性能的配方组合为稻壳粉159.25g(91%w/w)、黄原胶7.00g(5%w/w)、羧甲基纤维素钠8.75g(4%w/w)。

  5. Effect of CMC-g-PMMA on durability of rice husk-cement composites%CMC-g-PMMA对稻壳-水泥复合材料耐久性能的影响

    陈墨; 熊德胜; 韩福芹


    Rice husk-cement composites were prepared from rice husk treated with synthesized carboxymethylcellulose methyl methacrylate (CMC-g-PMMA). The composites were treated with dry-wet and freeze-thaw. The mechanical properties were tested and then the particle-matrix was observed with stereo microscope. The results indicated that when the addition of modifier CMC-gPMMA is 1.0%, it is almost not affected by freeze-thaw and dry-wet cycle, and the durability of the composites is relatively better.%采用羧甲基纤维素与甲基丙烯酸甲酯的接枝共聚物(CMC-g-PMMA)作为改性剂对稻壳碎料进行表面处理,制成稻壳-水泥复合材料.对该复合材料进行干湿和冻融处理,然后进行力学性能测试,并采用体视显微镜对其表面进行观察.结果表明,改性剂CMC-g-PMMA掺量为1.0%时,受冻融、干湿处理影响较小,稻壳-水泥复合材料的耐久性能较好.

  6. 25 t/h纯燃稻壳高低差速流化床锅炉的设计%Design of 25 t/h Rice-Husk Fired High-Low Bed Boiler



    The development of the JG-25/3.82-T ricehusk-fired fluidizedbed boiler and its structural characteristics were introduced, and the characters and combustion principles of industrial rejectamenta-residue of rice-husk were deeply analyzed. The successful experiences of rice-husk-residuce combustion with high-low bed combustion technology in boiler design were introduced, and supplied a good way for the general usage of high-moisture low-caloric industrial rejectamenta.%介绍了JG-25/3.82-T型稻壳流化床锅炉的开发过程、结构特点,深入分析了农业废弃物---稻壳的特性、燃烧机制。介绍了笔者在锅炉设计中成功采用高低差速床燃烧技术,焚烧稻壳的研制心得。

  7. Preparation of Zircon Encapsulated Carbon Pigment from Rice Husk as a Colorant%稻壳为碳源制备硅酸锆包裹炭黑色料的研究

    潘婷; 陈婷; 张筱君; 江伟辉; 刘健敏


    采用稻壳为碳源,无水四氯化锆(ZrCl4)为锆源,正硅酸乙酯(TEOS)为硅源,氟化锂(LiF)为矿化剂,聚乙烯醇缩丁醛(PVB)为分散剂,通过非水解溶胶-凝胶法制备了硅酸锆包裹炭黑(C@ZrSiO4)黑色色料。通过X射线衍射(XRD)、X射线荧光光谱仪(XRF)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对稻壳及色料的组成结构和显微形貌进行了表征,同时采用CIE-L*a*b*色度仪考察了C@ZrSiO4色料的色度。实验结果表明,以200℃干燥的稻壳为碳源有利于纯相ZrSiO4的合成。当干燥稻壳含碳量为硅酸锆质量的3.75 wt.%时制得的C@ZrSiO4色料发色效果最佳,色度值为L*=47.25,a*=0.59,b*=1.81。稻壳添加量过少时,原位碳化的炭黑含量不足影响呈色;稻壳添加量过多则不利于致密包裹结构的形成,最终导致L*值增大。%Zircon encapsulated carbon (C@ZrSiO4) black pigment was synthesized via non-hydrolytic sol-gel method, using rice husk powder as carbon source, anhydrous zirconium tetrachloride as zirconium source, tetraethyl orthosilicate (TEOS) as silicon source, lithium lfuoride (LiF) as mineralizer, polyvinyl butyral (PVB) as dispersant, respectively. The structure and morphology of rice husk powders and the pigments were studied by using X-ray diffraction (XRD), X-ray lfuorescence (XRF), scanning electron microscope (SEM) and transmission electron microscopy (TEM), while the chromatic value of the pigments was characterized by CIE-L*a*b*color system. The results show that pure ZrSiO4 can be prepared by using 200℃dried rice husk as carbon source. The proper weight ratio of carbon to ZrSiO4 is 3.75 wt.%. Therefore, the C@ZrSiO4 pigment exhibits excellent coloring performance with L*=47.25, a*=0.59, and b*=1.81. The deifciency of rice husk causes the shortage of carbon content, resulting in the poor chromatic performance. However, excessive rice husk hinders the dense coating’s formation, which

  8. Thickness-Controllable Silica Coating of CdTe QDs by Reverse Microemulsion Method for the Application in the Growth of Rice

    Aiwu Wang


    Full Text Available Herein, we report the synthesis and surface modification of CdTe quantum dots (QDs and the application in the rice growth. Water-soluble thioglycolic acid (TGA stabilized CdTe quantum dots were synthesized firstly and then the surface modification was conducted. II–VI semiconductor nanocrystals prefer to be coated with silica as inert materials to improve their chemical properties. The toxicity of QDs reduced after the modification. Silica coated QDs were used in the growth of rice seed and the effect was discussed. In our knowledge it is the first time we report that the silica coated QDs had nice effect on the growth of rice.

  9. Empleo de la cáscara de arroz en la fundición de piezas de acero al carbono//Using of rice husk in the carbon steel casting parts process

    Juan Carlos Cruz-Pérez


    Full Text Available Los materiales auxiliares desempeñan un papel importante en el aumento de la eficiencia tecnológica del proceso de fundición de piezas de acero al carbono. En este artículo se exponen los primeros resultados del empleo de la cáscara de arroz como material termoaislante en la obtención de piezas fundidas de acero al carbono. En los experimentos se evaluó la influencia  de seis combinaciones de las variables espesor de pared del casquillo y capa de cobertura. En la confección de los casquillos se utilizó cáscara de arroz triturada, la que posteriormente fue aglutinada con silicato de sodio, apisonada y endurecida con CO2, mientras que la cobertura se utilizó sin procesamiento previo. El mayor nivel de entrega de acero se obtuvo al emplear un espesor de casquillo de 65 mm y una altura de cobertura de 85 mm. El valor del ASAF generado por las variantes experimentales resultó igual o inferior a 0,48. Palabras claves: casquillo termoaislante, polvo de cobertura, cáscara de arroz, acero fundido.______________________________________________________________________________ Abstract Feeding auxiliary materials perform a very important role in improves technological efficiency of carbon steel casting parts process. In this article are exposing the first results in the rice husk using as an insulating material in such process. The variables sleeve thickness and covering thickness’ influence were evaluated in six combinations by means of experiments. In sleeves preparation was used crushed rice husk, which was agglutinated with sodium silicate, compacted and hardened with CO2, meanwhile as covering it was uses without previous preparation. The mayor liquid steel delivering level was get employing 65 mm sleeve thickness and 85 mm covering thickness. The ASAF value generated for experimental variants was equal or inferior to 0.48. Key words: insulating sleeve, riser sleeve, hot topping, rice husk, steel cast.


    Jorge Luis Akasaki


    Full Text Available Rice husk is an agroindustrial residue which, when adequately burned and ground, may become an important pozzolan to be added in mortars. One factor contributing to the feasibility of its use is that of the 10 million tons of rice produced annually in this country, two million tons of husk remain, which can produce about 400 thousand tons of ash - enough to supply the market for mortars, concrete andothers. This large amount of material has become an environmental problem because it is being discarded inappropriately. Seeking a viable use of rice husk ash in the civil construction, the present research studies the variation in mortar behavior with different levels of RHA (Rice Husk Ash. Prismatic specimens were used, measuring 25x25x285mm, moulded with 0% (reference, 5%, 10% and 25% RHA. The influence of the RHA’s was verified through the following tests: efficiency of pozzolanic materials in avoiding expansion and alkali-aggregate reaction. The result obtained in the expansion reduction test (NBR 12651 showed that RHA reduces considerably the expansion of mortars due to reaction with the alkalis in the cement(94.29%, with the minimum reduction required by the norm for a pozolan being 75%. Although the expansion values in the alkali-aggregate reaction test (ASTM C-1260 remained above the limit allowed to consider the material innocuous, RHA levels of 5% as well as 10% obtained better results (expanded less then the referenceline. = A casca de arroz é um resíduo agroindustrial que adequadamente queimada e moída, pode se tornar uma importante pozolana a ser adicionada em argamassas. Um fator que viabiliza o seu emprego, é que dos 10 milhões de toneladas de arroz que o país produz por ano, sobram dois milhões de toneladas de casca – que podem rendercerca de 400 mil toneladas de cinza, o suficiente para suprir o mercado de argamassas, concreto e outros. Esta grande quantidade de material produzido passa a se tornar um problema, porque

  11. The effect of the siliceous composites of rice husk and green tea on growth and development of Fragaria × ananassa Duch. regenerants during the adaptation to ex vitro conditions

    E. V. Ambros


    Full Text Available The effect of the composites of rice husk and green tea derived by mechanochemical method on growth and development of 6 cultivars of F. × ananassa Duch. during the adaptation to ex vitro conditions has been studied for the first time. The stimulating action of composite on both increment of the above-ground mass, and formation of the root system was revealed. The height of the rosette relative to the control was reliably increased by 1.3–4.1 times, the length of the root system – 1.1–2.0 times, the number of roots – 1.3–1.8 depending on the genotype.DOI: 10.14258/turczaninowia.18.3.5

  12. Optimization of extraction process for xylan from rice husk by response surface methodology%响应面法优化稻壳中木聚糖的提取工艺

    韩丹妮; 谢定


    Response surface methodology was used to optimize the conditions for alkaline extraction of xylan from rice husk, and the rice husk was pretreatmented by 3% sulfuric acid before use. The effects of extraction tempeature, NaOH concentration, solid-to-liquid ratio and extraction time on the yield of xylan were studied in single factor experiments. Subsequently, a regrssion model for the yield of xylan was established using a central composite design involving the above four factors at five levels and based on the model, response surface analysis was carried out to find out the optimum levels of these four factors. The results indicated that the optimum extraction conditions were: temperature 69. 8 ℃ , NaOH concetration 10. 7% , solid-to-liquid ratio 1 ' 13, and extraction time 5. 1 h. Under such conditions, the experimental yield of xylan was 76. 57%.%为提高稻壳中木聚糖的提取率,稻壳经3%的硫酸预处理后再用碱法进行木聚糖的提取,采用响应面法优化工艺条件,先对提取温度、NaOH浓度、固液比、提取时间4个因素进行单因素试验.根据单因素试验结果设计中心组合试验,以木聚糖提取率为考察指标,采用响应面分析法确定最优工艺参数.结果表明:提取温度69.8℃、NaOH浓度10.7%、固液比1∶13(m∶V)、提取时间5.1h.该条件下,木聚糖提取率可达76.57%.

  13. Study on Prosee for Synthesis of Zeolite A from Rice Husk Ash by Hydrothermal Treatment%利用稻壳灰水热合成A型沸石的工艺研究

    陈景茂; 吴晋沪; 王裕鑫


    [Objective]The study aimed to obtain the optimum conditions for the synthesis of zeolite A from the rice husk ash. [Method]The reaction temperature, alkali concn. , reagent silicon and aluminum ratio and reaction time in the synthesis of zeolite A from rice husk ash by the hydrothermal treatment were studied by hydrothermal method. [ Result] Under the conditions as the hydrothermal temperature of 100 ℃, NaOH concn. Of 2 mol/L, raw material silicon and aluminum ratio of 1.0 -2.0 and reaction time of 4 -6 h, the zeolite A with higher crystal-linity could be obtained. [ Conclusion ] The technology was simple and economical, and provided a new approach to the comprehensive utilization of bio-ash, which is in favour of achieving complete biomass energy utilization system and forming the sustainable development.%[目的]得出稻壳灰合成A型沸石的最佳条件.[方法]利用水热法对稻壳灰合成A型沸石的反应温度、碱浓度、反应物硅铝比和反应时间进行研究.[结果]在水热温度100℃,NaOH浓度为2 mol/L,原料硅铝比为1.0 ~2.0,反应时间为4~6h的条件下,可以得到结晶度较高的A型沸石.[结论]该方法工艺简单经济,为生物质灰的利用提供了一种思路,有利于实现完整的生物质能源利用系统,形成可持续发展.

  14. Thickness-Controllable Silica Coating of CdTe QDs by Reverse Microemulsion Method for the Application in the Growth of Rice

    Aiwu Wang; Yuhong Zheng; Feng Peng


    Herein, we report the synthesis and surface modification of CdTe quantum dots (QDs) and the application in the rice growth. Water-soluble thioglycolic acid (TGA) stabilized CdTe quantum dots were synthesized firstly and then the surface modification was conducted. II–VI semiconductor nanocrystals prefer to be coated with silica as inert materials to improve their chemical properties. The toxicity of QDs reduced after the modification. Silica coated QDs were used in the growth of rice seed and...

  15. The Characteristic and Activation of Mixed Andisol Soil/Bayat Clays/Rice Husk Ash as Adsorbent of Heavy Metal Chromium (Cr)

    Pranoto; Sajidan; Suprapto, A.


    Chromium (Cr) concentration in water can be reduced by adsorption. This study aimed to determine the effect of Andisol soil composition/Bayat clay/husk ash, activation temperature and contact time of the adsorption capacity of Cr in the model solution; the optimum adsorption conditions and the effectiveness of ceramic filters and purifiers to reduce contaminant of Cr in the water. The mixture of Andisol soil, Bayat clay, and husk ash is used as adsorbent of metal ion of Cr(III) using batch method. The identification and characterisation of adsorbent was done with NaF test, infrared spectroscopy (FTIR), X-ray diffraction (XRD). Cr metal concentrations were analyzed by atomic absorption spectroscopy. Sorption isotherms determined by Freundlich equation and Langmuir. The optimum conditions of sorption were achieved at 150°C activation temperature, contact time of 30 minutes and a composition Andisol soil / Bayat clay / husk ash by comparison 80/10/10. The results show a ceramic filter effectively reduces total dissolved solids (TDS) and Chromium in the water with the percentage decrease respectively by 75.91% and 9.44%.

  16. Preparation and Characterization of Amorphous Silica and Calcium Oxide from Agricultural Wastes

    Supachai Sompech


    Full Text Available Rice husk ash and bagasse ash were agricultural wastes that provide an abundanceof the silica (SiO2 source and the chicken eggshells and duck eggshells were important sources forcalcium oxide (CaO. Therefore, in this study the rice husk ash and bagasse ash were used as raw materials for synthesisofsilica powder,while chicken eggshells and duck eggshells were synthesized forthe calcium oxide.The results from the XRD pattern clearly showedthe structural formation of amorphous SiO2 and CaO phase. While the FTIR results indicated that the spectrums which displayedthe characteristic peaks of the functional groups presenting in the SiO2 and CaOpowder. However, the SEM images revealed that the particles agglomerated, various sizes and the particle size were found to be in micron level.

  17. Pendimethalin aplicado à casca de arroz e serragem para o controle de plantas daninhas em Ixora chinensis Lam. Pendimethalin applied on rice husks and sawdust for weed control on Ixora chinensis Lam

    André Luis Seixas


    Full Text Available A aplicação de herbicidas residuais à coberturas mortas pode aumentar a eficiência desses materiais no manejo da comunidade infestante. Objetivou-se, com este trabalho, avaliar a possibilidade de aplicação do pendimethalin à casca de arroz e à serragem para o controle de plantas daninhas em Ixora chinensis. Dois experimentos foram conduzidos aplicando-se o pendimethalin às coberturas mortas através de embebição e pulverização do herbicida, variando-se também a quantidade de cobertura utilizada. As espécies de plantas daninhas que ocorreram com maior frequência foram Alternanthera tenella, Blainvillea rhomboidea, Cenchrus echinatus e Commelina benghalensis. Há possibilidade de aplicação do herbicida pendimethalin à palha de arroz ou à serragem para controle de plantas daninhas em I. chinensis, principalmente quando ocorrem chuvas regulares e bem distribuídas. Há evidências de que a embebição da cobertura morta no herbicida seja um pouco mais eficiente no controle das plantas daninhas que a sua pulverização sobre a cobertura. Possivelmente, a quantidade de cobertura morta utilizada influencia na eficiência de controle, apesar deste fato não ter ficado claro neste trabalho.Applying herbicides at mulches may increase the efficiency of these materials for weed management. The objective of this research was to evaluate the possibility of pendimethalin applied on rice husks and sawdust for weed control on Ixora chinensis. In two field trials, pendimethalin was applied to the mulches through imbibition and spraying herbicide, also varying the amount of mulches. Higher frequent weeds were Alternanthera tenella, Blainvillea rhomboidea, Cenchrus echinatus and Commelina benghalensis. There are possibility of pendimethalin application on rice husks or sawdust for controlling weeds in I. chinensis mainly when regular and well-distributed rainfalls occur. There are evidences that the imbibition of these mulches to the herbicide

  18. Combustion of coffee husks

    Saenger, M.; Hartge, E.-U.; Werther, J. [Technical Univ. Hamburg-Harburg, Chemical Engineering 1, Hamburg (Germany); Ogada, T.; Siagi, Z. [Moi Univ., Dept. of Production Engineering, Eldoret (Kenya)


    Combustion mechanisms of two types of coffee husks have been studied using single particle combustion techniques as well as combustion in a pilot-scale fluidized bed facility (FBC), 150 mm in diameter and 9 m high. Through measurements of weight-loss and particle temperatures, the processes of drying, devolatilization and combustion of coffee husks were studied. Axial temperature profiles in the FBC were also measured during stationary combustion conditions to analyse the location of volatile release and combustion as a function of fuel feeding mode. Finally the problems of ash sintering were analysed. The results showed that devolatilization of coffee husks (65-72% volatile matter, raw mass) starts at a low temperature range of 170-200degC and takes place rapidly. During fuel feeding using a non water-cooled system, pyrolysis of the husks took place in the feeder tube leading to blockage and non-uniform fuel flow. Measurements of axial temperature profiles showed that during under-bed feeding, the bed and freeboard temperatures were more or less the same, whereas for over-bed feeding, freeboard temperatures were much higher, indicating significant combustion of the volatiles in the freeboard. A major problem observed during the combustion of coffee husks was ash sintering and bed agglomeration. This is due to the low melting temperature of the ash, which is attributed to the high contents of K{sub 2}O (36-38%) of the coffee husks. (Author)

  19. Preparation and structural characterization of graphene by rice husk%稻谷壳制备石墨烯纳米片及结构表征

    程金生; 万维宏; 陈信炎; 郑启祥


    Graphene possesses excellent chemical, physical, mechanical and thermal properties, which has attracted much attention in the past several years. Traditional Hummers-hydrazine hydrate method, mechanical stripping method, chemical vapor deposition (CVD) method, SiC substrate dependence epitaxial growth or other methods for graphene preparation use expensive graphite or gases, leading to high price of graphene. A case of point is Hummers-hydrazine hydrate method, by using the strong oxidants of KMnO4 and H2O2, graphene is prepared and has many defects (such as vacancy defect, Stone-Wales defect, doped defect and atomic absorption defect) in its structure, which would limit its application prospects. Husk, cornstalk or bagasse are common renewable biomass resources in Southern China (including Guangdong Province, Fujian Province, Hainan Province and Guangxi Zhuang Autonomous Region), which have had poor utilization ratio in the past decades. In this work, we tried to use the renewable husk resource with low price as the starting material, and by successive sulfate ions intercalation, N, N-dimethylacetamide (DMAC) thermal dispersion, microwave and ice splashing treatments, the husk-derived graphene with high added-value could be obtained. Acticarbon was prepared by high temperature carbonization, washing, vacuum drying, mesh screening and dialysis processes of husk renewable resource, which was graphitized under high-purity argon flow and high temperature (1 800℃) in the presence of Fe2O3, forming graphite crystallite with a size range of 4-25μm. In this work, the sulfate ions with large ionic radius (0.295 nm) were used as intercalation reagent of the resulted graphite crystallite, and by successive DMAC thermal dispersion, microwave and ice splashing treatments, graphene nanosheets could be obtained readily. The characteristics of the prepared material were measured by transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force

  20. Coprocessamento de cascas de arroz e pneus inservíveis e logística reversa na fabricação de cimento Rice husk and scrap tires co-processing and reverse logistics in cement manufacturing

    Miguel Afonso Sellitto


    describe the case of a manufacturer of cement that have deployed and consolidated the coprocessing of rice husk and scrap tires in clinker kilns, supported by reverse logistics practices. The research method was the case study. The company studied already use rice husk as alternative fuel and received an offer from the tyre industry for burning scrap tires in clinker kilns. To take advantage of the offer, the company integrated direct and reverse flows of raw materials, fuels and industrial waste, reducing more than 30% the transportation cost. The combined coprocessing partially replaced fossil fuels originated in the oil industry. The environmental gain more important was the burning reduction of about 10,000 tons of fossil fuel, which entailed the generation of about 30,000 tons of CO2 per year.

  1. Rice husk derived waste materials as partial cement replacement in lightweight concrete Utilização de resíduos derivados da casca de arroz como substitutos parciais do cimento no concreto leve

    Celso Yoji Kawabata


    Full Text Available In this study rice husk ash (RHA and broiler bed ash from rice husk (BBA, two agricultural waste materials, have been assessed for use as partial cement replacement materials for application in lightweight concrete. Physical and chemical characteristics of RHA and BBA were first analyzed. Three similar types of lightweight concrete were produced, a control type in which the binder was just CEMI cement (CTL and two other types with 10% cement replacement with, respectively, RHA and BBA. All types of similar lightweight concrete were prepared to present the same workability by adjusting the amount of superplasticizer. Properties of concrete investigated were compressive and flexural strength at different ages, absorption by capillarity, resistivity and resistance to chloride ion penetration (CTH method and accelerated carbonation. Test results obtained for 10% cement replacement level in lightweight concrete indicate that although the addition of BBA conducted to lower performance in terms of the degradation indicative tests, RHA led to the enhancement of mechanical properties, especially early strength and also fast ageing related results, further contributing to sustainable construction with energy saver lightweight concrete.Neste trabalho, cinzas de casca de arroz (RHA e cinzas de cama de frango (BBA, dois resíduos agrícolas, foram avaliadas para uso como substitutos parciais do cimento para produção de concreto leve. Características físicas e químicas de RHA e BBA foram analisadas. Três tipos semelhantes de concreto leve foram produzidos, um controle em que o ligante era totalmente cimento CEM I (CTL e dois outros tipos de concreto, com substituição de 10% com RHA e BBA, respectivamente. Todos os tipos de concreto leve foram feitos através do ajuste da quantidade de superplastificante para apresentarem a mesma trabalhabilidade. Propriedades de concreto investigados foram resistência à compressão e à flexão em diferentes idades

  2. Exergy analysis of rice husk gasification process in entrained-flow reactor%携带流反应器中稻壳气化过程的炯分析

    张亚宁; 赵义军; 孙绍增; 李炳熙


    Effect of air equivalence ratio ER on rice husk gasification in an entrained-flow reactor at different temperatures is analyzed using exergy concept. The results show that the contribution of gas component to exergy value is as follows: CO>H2>CH4> (N2, C2H4, CO2). With ER goes up the exergy value and its efficiency increase first and then decrease for product gas, however, the residual ratio and exergy efficiency decline first and then augment for unreacted carbon. At ER 0. 25 and reactor temperature 1000℃, total exergy value and exergy efficiency of product gas are 7983. 95 kJ · kg-1 and 54. 35%, respectively, and at ER 0. 28 and temperature 1000℃ , the residual ratio and exergy efficiency of unreacted carbon are 24. 82% and 21. 49%, respectively. Raising temperature can lift exergy value and exergy efficiency of product gas, but reduce residual ratio and exergy efficiency of unreacted carbon.%引 言生物质能作为一种可再生的清洁能源,可以减少CO2、NOx、SOx及颗粒物的排放[1],其开发利用受到世界各国的极大关注[2].生物质气化被认为是生物质利用的最有前途的能源转化方式之一[3],已经成为能源研发与利用的一大研究热点.研究结果表明,气化器或者锅炉是能源转化和利用过程中效率最低的一个操作单元[4],因此,气化器效率的提高能在很大程度上改善整个能源转化过程[5].

  3. Casca de arroz e palhada de soja na compostagem de carcaças de frangos de corte = Rice husks and soy straw as substrate for composting of broiler carcasses

    Paulo Giovanni de Abreu


    Full Text Available Avaliou-se a atuacao da casca de arroz e da palhada de soja como substrato para compostagem de carcaca de frangos de corte, observando a degradacao dos dois substratos e das carcacas pelo monitoramento da temperatura, peso das carcacas e dos substratos e analise fisicoquimica do produto final. As camaras foram montadas com carcacas de 10 aves recem abatidas, com quatro repeticoes no tempo. Instalou-se em cada camara um termopar para registro da temperatura. O substrato e as carcacas foram pesadas separadamente, no inicio, aos 15 e aos 30 dias de compostagem. Ao final de cada periodo, foram realizadas analises fisico-quimica de amostras de cada camara, avaliando-se o pH e os teores de materia seca, cinzas, P, N, K, Cu, Zn, Mn, Fe e carbono organico. Concluiu-se que a palhada de soja pode ser usada como alternativa para substrato de compostagem de carcacas de aves, atendendo a relacao C/N exigida pela legislacao ao final da terceira reutilizacao. A casca de arroz, da mesma forma, pode ser utilizada na compostagem de carcacas de aves, porem reutilizada por maior numero de vezes. A decomposicao das carcacas foi significativamente maior, em percentual, na palhada de soja aofinal do quarto periodo de compostagem (p „Tƒn0,05.The performance of rice husks and of soy straw were evaluated as substrate for on-farm poultry carcass composting, observing the degradation of the two substrate and of the carcasses through monitoring the temperature, weight of the carcasses and of the substrate and physiochemical analysis of the final product. The piles were arranged with carcasses of 10 recently slaughtered birds, with four repetitions in time. A thermo pair was installed in each pile to register the temperature. The substrate and the carcasses were weighed separately, in the beginning, day 15 and day 30 of composting. At the end of each period, the physiochemical analysis of samples were made from each pile, evaluating the pH, the dry material, ashes, P, N

  4. The efficiency of biosynthesis silica nanoparticles at removal of heavy metals Cr and Cu from aqueous solutions

    Mohammad Hossein Sayadi


    Full Text Available Background and Aim: Nanotechnology considered as one of the main management strategy in reducing negative effects of water pollution, which leads to treating of water inexpensive and more effective. This study aimed to investigate the removal of Cr and Cu from aqueous solutions using nano-silicate which is synthesized by rice husk. Materials and Methods: In the present study, functionalized nano-silica with rice husk was fabricated and characterized by FT-IR، TEM, SEM and XRD. The effect of adsorbent dosage, initial concentration and equilibrium of chromium and copper and contact time in removal of mentioned heavy metals were investigated. Finally, the adsorption isotherms were analyzed. Results: The silica nanoparticles had nearly spherical morphology with a uniform size of about 80 nm. However, the obtained functionalized silica nanoparticles were spherical (about 90 nm in diameter. Results showed that optimum adsorption of Cr and Cu contaminant obtained at 100 minutes, while the optimum amount of adsorbent for Cr and Cu were 125 and 100 mg respectively. The optimal concentration of Cr and Cu was 2 mg/l. The correlation coefficients of adsorption isotherms of Cr (R2Langmuir =0.9946 and Cu (R2Langmuir =0.999 showed the good agreement between the adsorption data and Langmuir model. Conclusion: The study showed that the silica nanoparticles can be produced using agricultural waste as a inexpensive and environmentally friendly method and can be used to removing of contaminants from the aquatic environment.

  5. Catalytic esterification via silica immobilized p-phenylenediamine and dithiooxamide solid catalysts

    Thana Jaafar Al-Hasani


    Full Text Available The p-phenylenediamine (PDA and dithiooxamide (DTO were immobilized onto silica from rice husk ash (RHA using 3-chloropropyltriethoxyilane (CPTES to form a solid catalyst denoted as RHAPDA and RHADTO, respectively. BET measurements of the catalysts showed the surface area to be 145 and 9.7 m2 g−1 with an average pore diameter of 9.8 and 10.9 nm, respectively. The catalytic performance of RHAPDA and RHADTO was tested in the esterification of ethyl alcohol with acetic acid. A conversion of 48% and 69% was achieved, respectively with 100% selectivity toward ethyl acetate.

  6. Growth and physiological responses of maize (Zea mays L.) to porous silica nanoparticles in soil

    Suriyaprabha, R.; Karunakaran, G.; Yuvakkumar, R.; Prabu, P.; Rajendran, V., E-mail: [K. S. Rangasamy College of Technology, Centre for Nano Science and Technology (India); Kannan, N. [K. S. Rangasamy College of Arts and Science, Department of Biotechnology (India)


    The present study aims to explore the effect of high surface area (360.85 m{sup 2} g{sup -1}) silica nanoparticles (SNPs) (20-40 nm) extracted from rice husk on the physiological and anatomical changes during maize growth in sandy loam soil at four concentrations (5-20 kg ha{sup -1}) in comparison with bulk silica (15-20 kg ha{sup -1}). The plant responses to nano and bulk silica treatments were analyzed in terms of growth characteristics, phyto compounds such as total protein, chlorophyll, and other organic compounds (gas chromatography-mass spectroscopy), and silica accumulation (high-resolution scanning electron microscopy). Growth characteristics were much influenced with increasing concentration of SNPs up to 15 kg ha{sup -1} whereas at 20 kg ha{sup -1}, no significant increments were noticed. Silica accumulation in leaves was high at 10 and 15 kg ha{sup -1} (0.57 and 0.82 %) concentrations of SNPs. The observed physiological changes show that the expression of organic compounds such as proteins, chlorophyll, and phenols favored to maize treated with nanosilica especially at 15 kg ha{sup -1} compared with bulk silica and control. Nanoscale silica regimes at 15 kg ha{sup -1} has a positive response of maize than bulk silica which help to improve the sustainable farming of maize crop as an alternative source of silica fertilizer.

  7. Growth and physiological responses of maize ( Zea mays L.) to porous silica nanoparticles in soil

    Suriyaprabha, R.; Karunakaran, G.; Yuvakkumar, R.; Prabu, P.; Rajendran, V.; Kannan, N.


    The present study aims to explore the effect of high surface area (360.85 m2 g-1) silica nanoparticles (SNPs) (20-40 nm) extracted from rice husk on the physiological and anatomical changes during maize growth in sandy loam soil at four concentrations (5-20 kg ha-1) in comparison with bulk silica (15-20 kg ha-1). The plant responses to nano and bulk silica treatments were analyzed in terms of growth characteristics, phyto compounds such as total protein, chlorophyll, and other organic compounds (gas chromatography-mass spectroscopy), and silica accumulation (high-resolution scanning electron microscopy). Growth characteristics were much influenced with increasing concentration of SNPs up to 15 kg ha-1 whereas at 20 kg ha-1, no significant increments were noticed. Silica accumulation in leaves was high at 10 and 15 kg ha-1 (0.57 and 0.82 %) concentrations of SNPs. The observed physiological changes show that the expression of organic compounds such as proteins, chlorophyll, and phenols favored to maize treated with nanosilica especially at 15 kg ha-1 compared with bulk silica and control. Nanoscale silica regimes at 15 kg ha-1 has a positive response of maize than bulk silica which help to improve the sustainable farming of maize crop as an alternative source of silica fertilizer.

  8. Origin of organism-dependent biogenic silica quartz formation.

    Sato, Kiminori


    Organism-dependent biogenic quartz formation in the steady-state environment is a phenomenon that can address the global environmental issues such as diagenetic evolution, biogeochemical cycling, and reservoir formation, but detailed studies have not been performed so far. Here, steady-state quartz formation is studied for amorphous silica of different biogenic origin on the basis of the recently established mechanistic model [Sato et al., J. Phys. Chem. C 2011, 115, 18131]. Amorphous silica originated from rice husks possesses angstrom-scale pores larger by 1.3 Å than those originated from diatom algae. The slight difference of pore size dramatically reduces activation energies of water diffusion by 78% and reactions of water molecules at pore surfaces by 47%, resulting in the reduction of activation energy of biogenic quartz formation by 64%. The present findings evidence that angstrom-scale pores intrinsically residing in the amorphous matrix are the organism-dependent origin of steady-state biogenic quartz formation.

  9. Performance of Recycled Aggregate Concrete Containing Micronised Biomass Silica

    Suraya Hani Adnan


    Full Text Available This paper presents a study on Micronised Biomass Silica (MBS that was produced from the controlled burning of waste Rice Husk. The MBS was used as pozzolan material to enhance the performance of Recycled Aggregate Concrete (RAC. Various percentages by mass of Micronised Biomass Silica were applied in the normal and recycled aggregate concrete cube samples. Compressive strength and water permeability tested on the samples at the age of 7, 14, 28 and 90 days showed that concrete containing MBS has attained higher compressive strength. Furthermore, the test on MBS also showed its ability to enhance the concrete water permeability. Lengthen to this; the study established a good correlation between the MBS content with compressive strength and water permeability coefficient.

  10. A Tribal Story Written in Silica: Using Phytoliths to Research the Effects of Mining on Past Wild Rice (Zizania palustris) Abundance in Sandy Lake, Minnesota

    Clarke, I. R.; Jones, M. A.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.


    Wild rice (Zizania palustris, manoomin) is an emergent aquatic plant that grows annually in the northern Great Lakes region of North America. This region is also rich in iron ore deposits and correspondingly has an extensive history of mining activities. Wild rice no longer grows in some areas where it was previously abundant. Sandy Lake, located in St. Louis County on federally protected lands that are ceded territory of the Fond du Lac Band of Lake Superior Chippewa in Minnesota and downstream of the nearby U.S. Steel Minntac mine, was selected as a test site. This lake has a history of ricing activities by the Ojibwe (Chippewa) People, for whom manoomin has cultural importance. Lake cores were taken on June 17, 2014 by LacCore and FDLRM staff and samples were obtained. This project used phytolith analysis to answer the question of past wild rice presence and abundance in Sandy Lake. Phytoliths are microscopic opal silica deposits produced in some plants. Zizania palustris produces phytolith morphotypes that are unequivocally diagnostic of this species in this region. Microscopic slides were prepared and analyzed for wild rice phytoliths. Concentration values ranged from 25 to 4379 phytoliths per cm3/year, and wild rice accumulation figures ranged from 7 to 789 phytoliths/cm2/year, the maximum values of which occurred in the 1920s and generally declined to the current lowest levels observed. Mining has likely impacted wild rice populations by causing increased sulfate levels and possibly contributing to higher lake levels.

  11. Avaliação térmica de placas de argamassa de cimento e casca de arroz aquecidas por resistência elétrica Thermal evaluation of rice husk and cement mortar boards warmed by electric resistance

    Luiz A. Rossi


    Full Text Available Neste trabalho, apresenta-se uma proposta alternativa para o sistema de aquecimento de piso por resistência elétrica em granjas de aves e suínos. Após o dimensionamento do sistema, foram confeccionadas placas com argamassa de cimento, areia e casca de arroz, com diferentes traços, a fim de avaliar esse material alternativo de construção, sendo construído um controlador eletrônico de temperatura para dar mais autonomia ao sistema de aquecimento. O sistema mostrou-se eficiente no controle da temperatura da placa. Dentre os traços analisados, aquele com a placa mista de argamassa convencional e casca de arroz demonstrou melhor desempenho.An alternative proposal for floor heating system by means of electric resistance for both chick and piggy installation is presented in this work. Several formulations of rice husk and cement mortar boards were used. An electronic device controlled all board temperature. This system presented a good efficiency design. The conventional cement mortar mixed with rice husk showed a better performance.


    moisture content, and fertilizer and silica application. The susceptibility of the rice plant to rice blast disease varied inversely with the moisture...content of the soil irrespective of the amount of fertilizer or silica applied or of the stage of growth of the plant. Dryness of the soil tended to...fertilization were more easily infected than plants grown on irrigated soil with double the amount of fertilizer . This proves that even with double the

  13. Efeito de cascas de café e de arroz dispostas nas camadas do solo sobre a germinação e o crescimento inicial do caruru-de-mancha Allelopathic effect of coffee and rice husks arranged in soil layers on the germination and initial growth of Amaranthus viridis

    J.C.F. Santos


    Full Text Available Estudos dos efeitos dos resíduos de plantas pela utilização de coberturas mortas no controle das plantas daninhas têm apresentado dificuldade de determinar a diferenciação entre alelopatia e competição. Atualmente, muitas pesquisas têm se referido a critérios que propõem evidência à alelopatia. Este trabalho em casa de vegetação visou determinar os efeitos alelopáticos proporcionados pelas cascas de café e de arroz sobre o caruru-de-mancha, por meio das disposições desses resíduos nas camadas do solo. O delineamento experimental foi o de blocos casualizados, com os tratamentos em quatro repetições e organizados num esquema fatorial (3x3, sendo cascas de café e de arroz e vermiculita expandida como um fator e suas disposições, com resíduos depositados no topo, incorporados na superfície e incorporados no fundo, como segundo fator. Como testemunha foi usado um tratamento adicional sem cobertura. De modo geral, resíduos de cascas proporcionaram inibição da germinação e estímulo ao crescimento do caruru-de-mancha. A casca de arroz proporcionou menor índice de velocidade de emergência e germinação de sementes do que a casca de café. A casca de café depositada no topo proporcionou maior crescimento e maior peso da matéria seca do caruru-de-mancha, seguido pela mesma casca incorporada na superfície do solo.Studies of plant residue effects involving mulches to control weeds in perennial crops are difficult to carry out due to the need to differentiate between allelopathy and competition. Many researches, nowadays, refer to criteria proving allelopathy. This work was established under greenhouse conditions to determine the allelopathic effects of coffee and rice husks on Amaranthus viridis through their arrangements in soil layers. The experimental design was a randomized block with four replications, arranged in a 3 x 3 factorial scheme, with coffee and rice husks and expanded vermiculite being one factor and

  14. 用稻壳硅源水热合成P型分子筛的研究%Study on the hydrothermal synthesis of P-type zeolite from rice husk silicon

    杨君; 马红超; 付颖寰; 宋宇; 王永为; 于春玲; 董晓丽


    利用稻壳中丰富的氧化硅为硅源,以Al(OH)3为外加铝源,采用水热法合成P型分子筛.通过实验得到制备P型分子筛的最佳条件:硅铝摩尔比(SiO2/A12O3)为5.6,钠硅摩尔比(Na2O/SiO2)为1.43,水钠摩尔比(H2O/Na2O)为18.3,反应温度为85℃,反应时间为24 h.X射线衍射(XRD)与扫描电镜分析表明,该条件下合成的P型分子筛具有较高的结晶度,无杂相,其Ca2+(以CaCO3计)交换容量可达320 mg/g.该方法为农业副产物的再利用提供了一条有效途径.%P-type zeolite was hydrothermal synthesized with rice husk as silicon source and A1(OH)3 as Al source. Results showed that the optimum composition for synthesis of P-type zeolite was SiO2/AlzO3 molar ratio of 5. 6, Na2O/SiO2 molar ratio of 1. 43, and H2O/Na2O molar ratio of 18. 3, which could give maximum calcium ionic exchange capacity of P-type zeolite for 320 mg/g (equivalent to CaCO3) when the crystallization temperature was 85 ℃ and reacted for 24 h. Analysis of XRD and SEM indicated that the P zeolite synthesized under optimum condition had pure form, single phase and high crystalline, it could be used as wash auxiliary. The method provided an effective way for the reuse of agricultural by-products.

  15. Diseño de un sistema para el aprovechamiento integral de la cáscara de arroz; Design of a system for integral use of the rice husk

    Michel Errasti Cabrera


    Full Text Available El presente trabajo tiene como objetivo realizar el diseño de un horno que permitirá la combustión controlada de la cáscara de arroz para obtener una ceniza con propiedades puzolánicas; el cual es un producto demandado para la elaboración de materiales refractarios y como adición reactiva en los hormigones de altas prestaciones. El estudio estará centrado en la CPA productora de arroz “Eulalio García”, donde se pretende aprovechar la energía térmica de los gases de la combustión en distintos procesos agroindustriales. Los resultados muestran que la dimensión volumétrica de la cámara de combustión será de 0,72×0,72×1,06 m, mientras que la altura y el diámetro de la chimenea serán de 6,40 m y 0,42 m, respectivamente. El coeficiente de exceso de aire será de 1,55 y el volumen de aire a suministrar 4,34 m3/kgCA. La eficiencia del horno se estimó en 86,63 % y el calor útil en 10585,74 kJ/kgCA. The present paper aims to make the design of a furnace that allow controlled burning of rice husk for obtain a pozzolanic ash, which is a product demanded for the production of refractory materials and as an reactive addition in high performance concretes. The study will focus on CPA "Eulalio Garcia", which aims to exploit the thermal energy from the combustion gases in different agro-industrial processes. The results show that the volumetric dimension of the combustion chamber will be 0.72 × 0.72 × 1.06 m, while the height and diameter of the stack will be of 6.40 m and 0.42 m, respectively. The excess air ratio will be 1.55 and the volume of air to provide 4.34 m3/kgCA. Furnace efficiency was estimated to be 86.63 % and useful heat in 10585.74 kJ / KgCA.

  16. Caracterização física e mecânica de argamassas à base de cimento Portland e cinza de casca de arroz residual Physical and mechanical characterization on Portland cement mortar with rice husk ash addition

    Michelle S Rodrigues


    Full Text Available A casca de arroz, utilizada como fonte de energia em indústrias de beneficiamento de arroz, converte-se, depois da queima, em uma cinza residual. Esse resíduo, ainda sem um destino adequado, é muitas vezes depositado em grandes áreas abertas e provoca elevado impacto ambiental. Este trabalho teve como objetivo avaliar a viabilidade de utilização da cinza de casca de arroz (CCA residual na produção de argamassas, como substituta parcial do cimento. A caracterização da CCA foi realizada por meio da análise de fluorescência de raios-X (composição química, análise do teor de carbono e difração de raios-X; também foi realizada análise granulométrica a laser. Os corpos de prova foram submetidos a dois tipos de exposição: ambientes externo e interno, com duração máxima de cinco meses. Foram realizados os ensaios de resistência à compressão simples e não destrutivo (velocidade do pulso ultrassônico - VPU. Embora as argamassas tenham apresentado bom desempenho mecânico, os ensaios de pozolanicidade indicaram que a cinza de casca de arroz residual utilizada não é uma pozolana, mas pode ser utilizada em matrizes cimentícias como material inerte (filler.Rice husk, employed as an energy source at milling industries in Brazil generates, after burning, a dark ash. This residue is not yet conveniently disposed, being currently dumped on large areas, causing environmental problems. This research intended to evaluate the applications of residual rice husk ashes (RHA as a partial replacement of cement for mortar production. Rice husk ash was chemically characterized through X-ray fluorescence, determination of carbon content, X-ray diffraction, and laser granulometric analysis. Mortar specimens were submitted to two different exposure conditions: internal and external environments at a maximum period of five months. Physical-mechanical testing were compressive strength and ultrasonic pulse velocity (UPV. Although presenting good

  17. Aplicação da casca de arroz na adsorção dos íons Cu2+, Al3+, Ni2+ e Zn2+ Utilization of rice husk to remove Cu2+, Al3+, Ni2+ and Zn2+ from wastewater

    Aparecida Maria Simões Mimura


    Full Text Available The potential use of rice husk as biosorbent to remove Cu2+, Al3+, Ni2+ and Zn2+ ions from aqueous solutions was investigated under both noncompetitive and competitive conditions. The biosorbent was used in the form of particles with size smaller than 0.5 μm and in the concentration of 500 mg L-1 (dry weight. The experiments were performed using batch adsorption technique for concentrations of 10, 30 and 70 mg L-1 of metal ions at pH 4.0 and 5.0. The chemical speciation of metals in the experimental conditions used in this work was predicted by the software Visual MINTEQ 2.6.

  18. A lucrative chemical processing of bamboo leaf biomass to synthesize biocompatible amorphous silica nanoparticles of biomedical importance

    Rangaraj, Suriyaprabha; Venkatachalam, Rajendran


    Synthesis of silica nanoparticles from natural resources/waste via cost effective route is presently one of the anticipating strategies for extensive applications. This study reports the low-cost indigenous production of silica nanoparticles from the leftover of bamboo (leaf biomass) through thermal combustion and alkaline extraction, and examination of physico-chemical properties and yield percentage using comprehensive characterization tools. The outcome of primed silica powder exhibits amorphous particles (average size: 25 nm) with high surface area (428 m2 g-1) and spherical morphology. Despite the yield percentage of silica nanoparticles from bamboo leave ash is 50.2%, which is less than rice husk ask resources (62.1%), the bamboo waste is only an inexpensive resource yielding high purity (99%). Synthesis of silica nanoparticles from natural resources/waste with the help of lucrative route is at present times one of the anticipating strategies for extensive applications. In vitro study on animal cell lines (MG-63) shows non-toxic nature of silica nanoparticles up to 125 µg mL-1. Hence, this study highlights the feasibility for the mass production of silica nanoparticles from bamboo leave waste rather using chemical precursor of silica for drug delivery and other medical applications.




    -se uma maior remoção no carvão que se ativo a uma temperatura de 600°C, um tempo de ativação de 30 minutos e uma concentração da solução de 1% p/p; a remoção foi do 72,8% comparado com a casca de arroz ativada com H3PO4 que foi do 54,5% e a cinza de casca de arroz 49,2%.Several adsorbent materials were prepared from rice husk, a lignocellulosic waste from agro-industry, for the removal of chromium present in the effluents of the tanning, due to its high toxicity in the health and to environmental level. The rice husk was evaluated as ash and activated coal with phosphoric acid or hydroxide of sodium as activating agents. The experimental part consisted of calcination of the rice husk, chemical activation, characterization, tests of adsorption and tests of atomic absorption; obtaining better results the adsorbent activated with hydroxide of sodium. The activation of the rice husk with NaOH required a series of experiments to determine the best conditions of operation in the process of obtaining of the activated coal. A major removal was obtained in the coal that was activated at 600°C 30 minutes of activation time and 1% p/p of solution concentration; the removal was of the 72,8 % compared with the rice husk ash activated with H3PO4 that was of the 54,5% and the rice husk ash 49,2%.

  20. 稻秸皮层硅物质的分布及超微构造%Distribution and ultrastructure of silica on rice straw surface

    潘明珠; 杜俊; 甘习华; 吕歆悦


    Agricultural residues are annually renewable, widely distributed, and available around the world. Each year, there is around 205 million tons of rice straws produced in China. Rice straw has been traditionally used as organic fertilizer, energy, and raw material for paper and bio-composites. Rice is a typical silicon-accumulating plant. Silica is absorbed in the form of monosilicic acid. Monosilicic acid follows water in the transpiration stream, and finally deposits as an amorphous opal (SiO2). These amorphous opals are accumulated in cell walls of shoots, intercellular regions, and epidermic cells via biosilicification. Silica in rice plants is considered to be an essential element, although the beneficial effects of silica on growth and yield are partly attributed to the effects of the element on protecting plant from fungal diseases and insects. Furthermore, rice straw is a natural cellulose-SiO2 hybrid nanocomposite. The cell wall could be a matrix for self-assembly of biosilica. Within cell wall, silica is bound in cellulose, hemicellulose and lignin, while SiO2 nanoparticles act as reinforcement partners during the synthesis of such bioinorganic nanocomposites. Bioinorganic hybrid nanocomposites have become well known owing to their unique properties and widespread potential application in different areas, such as catalysis, adsorption, separation, and drug delivery system. In this paper, the sheath, stem, node and ear of rice straw were selected respectively, and the total contents of SiO2 in tissues of rice straw were measured as follows: the weighted test samples were transferred to a crucible, carbonized gently over a burner, and then kept in a muffle furnace. The resulted ash was immersed in hydrochloric acid. The acid-insoluble residue was filtered, washed with hot water until no chlorides were detectable, ignited, and finally SiO2 was obtained and weighted. The distribution of silica on the surface of sheath and stem was investigated with the scanning

  1. Microstructure characteristic and X-ray energy dispersive microanalysis of combustion ash of rice husk and rice straw%稻壳与稻秆灼烧灰颗粒的微观形态特征及其能谱分析

    姚锡文; 许开立


    In the past decades, sustainable development and increasing fuel demand have necessitated the identification of possible energy sources. The utilization of biomass will reach up to 50 million tons in China after ten years. Nowadays, many countries are putting great emphasis on the exploration of biomass energy. The techniques used are various such as combustion, gasification, pyrolysis, hydrogen production. The use of the biomass as fuel generates a large amount of residual ash which causes serious environmental problems, as the biomass ash is easy to melt and volatilize. During the thermo-chemical conversion process, the residual inorganic materials also form the slag inside the boiler and the fly ash deposits on the tail heating surface, which retards heat transfer, deteriorates burning, and causes high temperature corrosion and super heat explosion. As one kind of clean and renewable energy, rice husk (RH) and rice straw (RS) are the main by-products during the process of rice processing. Especially, in comparison with other agricultural wastes, the ash content of RH is much higher. After thermo-chemical conversion, the inorganic mineral matters left are ashes, which can easily bond with tar and lead to the phenomenon of slagging, fouling and corrosion for the thermo-chemical conversion equipments. Therefore, in this study, the analysis of microstructure characteristics and elemental composition of these ashes from the combustion of RH and RS at 600℃ and 815℃ respectively was comprehensively conducted by using the scanning electron microscopy (SEM) and the energy dispersive X-ray microanalysis (EDX). The influence of ashing temperature on the particle size distribution, micromorphology, particle surface, interior structure and elemental composition of biomass ash was investigated. The results showed that the higher the ashing temperature was, the smaller the size of the ash would be. With the increase of ashing temperature, the distribution of ash was more

  2. 添加木炭改善猪粪稻壳好氧堆肥工艺及质量%Improving pig manure and rice husk compost technology and quality by wood charcoal addition

    李荣华; 张广杰; 张增强; 王权; 孙西宁


    In order to promote waste recycling and investigate the effect of hardwood-based biochar additives in the process of pig manure composting, the pig manure was mixed with rice husk and further amended with oak wood charcoal at 0, 2.5%, 5.0%, 7.5%, and 10.0%in dry weight before being aerobically composted for 60 days. The parameters, such as temperature, water content, pH, electrical conductivity (EC), organic carbon, C/N ratio, total nitrogen, NH4+-N, NO3--N, NH3, etc., were detected through chemical analysis. The organic matter degradation process was evaluated by the Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electronic Microscopy (SEM) methods. The FTIR analysis showed that the contents of the compounds with-OH,-CH3, and-CH2 groups decreased with time, while the contents of the compounds with-C=O, C-O-C,-COO, and aromatic groups increased with time during the 60 days of composting. The compost sample SEM analysis proved that the mixture particle size decreased with the progress of time and the amount of wood charcoal. During the 60 days composting, as the wood charcoal addition amount increased, the organic carbon contents in all the treatments decreased 12.23%, 13.77%, 14.88%, 15.36%, and 15.86%, respectively; the C/N ratio decreased 47.80%, 54.98%, 56.97%, 60.03%, and 65.73%, respectively. Compared to the control, the addition of wood charcoal had no significant effect on pH variation, and the final compost pH kept the balance at 8.0. Wood charcoal addition extended high-temperature processing times by 2-5 days, increased the water contents, and decreased the EC value during composting. During the 60 days composting, as the wood charcoal addition amount increased, the moisture content decreased 15.9%, 13.0%, 11.1%, 10.1%, and 7.8%, respectively; while the EC value in the wood charcoal added treatment were decreased 0.07, 0.15, 0.23, and 0.28 mS/cm than that of the control, respectively. Addition of oak wood charcoal additives could enhance the

  3. Evidence for Non-Transmission of Rice Yellow Mottle Virus (RYMV through Rice Seed

    Sy, AA.


    Full Text Available An indexing of the organs (radicle and plumule and components (husk, endosperm and embryo of rice seeds using Enzyme Linked Immunosorbent Assay (ELISA was carried out to detect Rice yellow mottle virus (RYMV and establish the exact location of the virus in the rice seed. RYMV was detected only in the husk (seed coat but not in the endosperm, plumule, radicle, nor embryo. None of the seedlings raised from the seeds expressed RYMV symptoms. No virus particle was detected by the ELISA test in the leaves of the screenhouse-reared plants obtained from seeds of infected plants. The results indicate that RYMV is apparently not transmitted through rice seed probably because the virus is seed-borne in the husk (seed coat of mature rice seeds.

  4. Silicon isotope fractionation between rice plants and nutrient solution and its significance to the study of the silicon cycle

    Ding, T. P.; Tian, S. H.; Sun, L.; Wu, L. H.; Zhou, J. X.; Chen, Z. Y.


    The silicon isotope fractionation between rice plant and nutrient solution was studied experimentally. Rice plants were grown to maturity with the hydroponic culture in a naturally lit glasshouse. The nutrient solution was sampled for 14 times during the whole rice growth period. The rice plants were collected at various growth stages and different parts of the plants were sampled separately. The silica contents of the samples were determined by the gravimetric method and the silicon isotope compositions were measured using the SiF 4 method. In the growth process, the silicon content in the nutrient solution decreased gradually from 16 mM at starting stage to 0.1-0.2 mM at harvest and the amount of silica in single rice plant increased gradually from 0.00013 g at start to 4.329 g at harvest. Within rice plant the SiO 2 fraction in roots reduced continuously from 0.23 at the seedling stage, through 0.12 at the tiller stage, 0.05 at the jointing stage, 0.023 at the heading stage, to 0.009 at the maturity stage. Accordingly, the fraction of SiO 2 in aerial parts increased from 0.77, through 0.88, 0.95, 0.977, to 0.991 for the same stages. The silicon content in roots decreased from the jointing stage, through the heading stage, to the maturity stage, parallel to the decrease of silicon content in the nutrient solution. At the maturity stage, the silicon content increased from roots, through stem and leaves, to husks, but decreased drastically from husks to grains. These observations show that transpiration and evaporation may play an important role in silica transportation and precipitation within rice plants. It was observed that the δ30Si of the nutrient solution increased gradually from -0.1‰ at start to 1.5‰ at harvest, and the δ30Si of silicon absorbed by bulk rice plant increased gradually from -1.72‰ at start to -0.08‰ at harvest, reflecting the effect of the kinetic silicon isotope fractionation during silicon absorption by rice plants from nutrient

  5. Preparation of Rice Husk Carbon-based Solid Acid Catalyst for the Dehydration of Xylose to Furfural%稻壳碳基固体酸催化剂的制备及在木糖脱水制备糠醛反应中的催化性能

    梁玉; 陈志浩; 梁宝炎; 胡哲; 杨晓敏; 王子忱


    A carbon-based solid acid catalyst, prepared by the sulfonation of rice husk carbon, was proved to be an efficient and environmental benign catalyst for the dehydration of xylose to furfural. The catalyst was characterized by Fourier transform infrared spectroscopy(FTIR), elemental analysis and Scanning Electronic Microscopy( SEM) . The total acid site concentrations of the catalyst samples were obtained using standard acid-base back titration. The acid site concentration of 1. 03 mmol/g was obtained when the 4. 0 g of rice husk carbon was sulfonated by 15 mL of H2 SO4 at 150 ℃ for 8 h. The effects of solvent, reaction temperature and time on the dehydration of xylose to furfural catalyzed by the rice husk carbon-based solid acid catalyst were studied. The results indicate that the yield of furfural increases gradually with the increase of reaction tempera-ture and with the prolonger of the reaction time. The catalytic performance of the synthesized catalyst is better when using DMSO as reaction solvent than that of using water as solvent. A maximum furfural yield of 75. 8%was achieved. The repeated usability and regeneration of the catalyst was investigated.%以工业生产中碱法溶硅剩余的稻壳残渣为碳源,采用硫酸磺化法制备稻壳碳基固体酸催化剂,考察了其催化木糖脱水制备糠醛的性能.采用红外光谱、元素分析及表面酸浓度测定等手段对催化剂进行了表征.对固体酸催化剂的制备条件进行了优化,所得催化剂的表面酸浓度可达1.03 mmol/g.以木糖脱水制备糠醛为模型反应,考察了溶剂类别、反应温度和反应时间对固体酸催化剂催化性能的影响.实验结果表明,以二甲基亚砜( DMSO)为反应溶剂效果优于水,并且随着反应温度的升高和反应时间的延长,反应产率逐渐增加,最高可达75.8%.此外,还对催化剂的循环性能进行了研究,探讨了其失活原因和再生方法.

  6. 气相SiO2与稻壳SiO2阻燃协效作用研究%Synergistic Effect of Rice Husk Silica and Gas Phase Silica on Fire Retardant System

    石红; 刘学清; 张远方; 杨志兰


    将稻壳SiO2或气相SiO2与含膦阻燃剂甲基环己基次膦酸铝[Al (MHP)]复配,进一步应用到环氧树脂(EP)中.利用UL94垂直燃烧和氧指数(LOI)测试及热重分析,着重研究了SiO2的用量及类型对Al(MHP)/EP复合体系的阻燃协效作用.结果表明,当Al(MHP)和SiO2总质量分数保持20%,添加稻壳SiO2的复合材料具有较好的阻燃性能.而且,两种SiO2的加入对材料的起始热分解温度影响不大,但能降低复合材料的热分解速率并促进成炭.

  7. Survey on Contamination of Fusarium Mycotoxins in 2011-harvested Rice and Its By-products from Rice Processing Complexes in Korea

    Soohyung Lee


    Full Text Available To investigate Fusarium mycotoxin contamination in rice samples from rice processing complexes (RPCs, paddy rice and rice-milling products such as husks, brown rice, blue-tinged rice, broken rice, rice bran, discolored rice, and polished rice were collected from nationwide in 2012. Three hundred seventy one samples of rice and its by-products were analyzed for three trichothethenes including nivalenol (NIV, deoxynivalenol (DON, and zearalenone (ZEA by LC/MS. Discolored rice samples were found to have the highest contamination of DON, NIV or ZEA, followed by broken rice. Polished rice samples were largely free from mycotoxins, except three samples which were contaminated with NIV or DON at safety level. The rice byproduct samples were contaminated at higher level and frequencies than polished rice samples.

  8. Adsorption of Ca(II, Mg(II, Zn(II, and Cd(II on Chitosan Membrane Blended with Rice Hull Ash Silica and Polyethylene Glycol

    F. Widhi Mahatmanti


    Full Text Available In this research, chitosan based membrane blended with rice hull ash (RHA silica and polyethylene glycol (PEG has been applied as adsorbent of Ca(II, Mg(II, Zn(II and Cd(II in an aqueous solution. Membrane was synthesized by blending RHA silica and polyethylene glycol into chitosan. Silica and polyethylene glycol blended into the chitosan to improve the mechanical properties and the membrane porous. The membrane was characterized using Fourier Transform infrared (FTIR spectroscopy, X-Ray Diffraction (XRD, Scanning Electron Microscopy (SEM, and swelling degree analyzer. Adsorption of metal ions investigated was conducted in a batch system with variation of pH, initial ion concentration and contact time. Thermodynamics and kinetics of adsorption were evaluated based on the adsorption data at initial metal ion concentration and contact time variations, respectively. Results showed that the optimum condition of adsorption was at pH 9.0 for Ca(II, 6.0 for both Mg(II and Zn(II and 5.5 for Cd(II, and contact time of 24 h for all ions investigated. Kinetics of all investigated metal ion adsorption followed a kinetic model of pseudo-second-order. Adsorption of Ca(II and Mg(II on the membrane fitted to Freundlich model with the affinity of 1.266 and 1.099, respectively; and Zn(II and Cd(II fitted to Langmuir one with the capacity of 182 and 106 µmol/g, respectively.

  9. How Rice (Oryza sativa L.) Responds to Elevated As under Different Si-Rich Soil Amendments.

    Teasley, William A; Limmer, Matthew A; Seyfferth, Angelia L


    Several strategies exist to mitigate As impacts on rice and each has its set of trade-offs with respect to yield, inorganic As content in grain, and CH4 emissions. The addition of Si to paddy soil can decrease As uptake by rice but how rice will respond to elevated As when soil is amended with Si-rich materials is unresolved. Here, we evaluated yield impacts and grain As content and speciation in rice exposed to elevated As in response to different Si-rich soil amendments including rice husk, rice husk ash, and CaSiO3 in a pot study. We found that As-induced yield losses were alleviated by Husk amendment, partially alleviated by Ash amendment, and not affected by CaSiO3 amendment. Furthermore, Husk was the only tested Si-amendment to significantly decrease grain As concentrations. Husk amendment was likely effective at decreasing grain As and improving yield because it provided more plant-available Si, particularly during the reproductive and ripening phases. Both Husk and Ash provided K, which also played a role in yield improvement. This study demonstrates that while Si-rich amendments can affect rice uptake of As, the kinetics of Si dissolution and nutrient availability can also affect As uptake and toxicity in rice.

  10. Microstructure Assessment of Metakaolin Based-Geopolymers Produced with Alternative Silica Sources Exposed to High Temperatures

    Villaquirán-Caicedo Mónica Alejandra


    Full Text Available Ceramic materials more environment friendly and with similar or even better performance than traditional ones can be produced by alkali activation of natural minerals, wastes or industrial by-products. The present study assesses the effect of exposure at 600° and 1200°C of a MK-based geopolymers. Rice husk ash (RHA and silica fume were modified chemically in order to obtain an alternative alkali activator. Exposure to elevated temperatures leads to dehydration of the reaction products and structural reorganization associated with the crystallization of the gel to leucite (KAlSi2O6 and kalsilite (KAlSiO4. The structural changes associated with the thermal treatment also promote a densification and reduction of porosity. The unreacted MK particles embedded into the geopolymeric gel lead to the formation of mullite (2Al2O3 × SiO2 after the thermal treatment at 1200°C.

  11. Feasibility of ethanol production from coffee husks.

    Gouvea, B M; Torres, C; Franca, A S; Oliveira, L S; Oliveira, E S


    The objective of this work was to evaluate the feasibility of ethanol production by fermentation of coffee husks by Saccharomyces cerevisiae. Batch fermentation studies were performed employing whole and ground coffee husks, and aqueous extract from ground coffee husks. It was observed that fermentation yield decreased with an increase in yeast concentration. The best results were obtained for the following conditions: whole coffee husks, 3 g yeast/l substrate, temperature of 30 degrees C. Under these conditions ethanol production was 8.49 +/- 0.29 g/100 g dry basis (13.6 +/- 0.5 g ethanol/l), a satisfactory value in comparison to literature data for other residues such as corn stalks, barley straw and hydrolyzed wheat stillage (5-11 g ethanol/l). Such results indicate that coffee husks present excellent potential for residue-based ethanol production.

  12. 纳米TiO2含量对PVC/稻壳粉木塑复合材料性能的影响%Effects of Nano TiO2 Content on Properties of PVC/Rice Husk Powder Wood-Plastic Composites

    王宣博; 陈小丹; 陈佳伟; 刘玉涛; 姚雪霞


    Nano TiO2,rice husk powder,poly(vinyl chloride) (PVC) and stabilizer and so on were blended according to certain proportion to prepare PVC/rice husk powder wood plastic composites with the extrusion. The effects of nano TiO2 content on the properties of the wood plastic composites were examined. The experimental results show that the mechanical properties,waterproof performance and thermal stability ofthe wood plastic composites first increase then decrease,but surface colors become shallow gradually along with nano TiO2 content increasing. The wood plastic composite which the content of nano TiO2 is 1.00 phr has best comprehensive properties,compared with non-adding nano TiO2 wood plastic composite,the tensile strength,impact strength,and bending strength are increased by 40.6%,62.2% and 19.7% respectively,the water absorption rate for 8 days is reduced from 2.5% to 1.6%,the contact angle is increased from 78.5°to 82.1°,and the content of remaining carbon at 800℃ is increased from 21.1% to 29.5%. The surface color of the wood plastic composites become shallow gradually along with nano TiO2 content increasing.%将纳米TiO2、稻壳粉、聚氯乙烯(PVC)和稳定剂等按一定比例混合,用挤出成型法制备PVC/稻壳粉木塑复合材料。考察纳米TiO2添加量对PVC/稻壳粉木塑复合材料性能的影响。实验结果表明,随着纳米TiO2含量的增加,木塑复合材料的力学性能、防水性能和热稳定性呈现先增加后降低的趋势,但木塑复合材料的表面颜色却随着纳米TiO2含量的增加而逐渐变浅。当纳米TiO2含量为1.00份时,木塑复合材料的综合性能最好,与未添加纳米TiO2的木塑复合材料相比,其拉伸强度、冲击强度和弯曲强度分别提高了40.6%,62.2%和19.7%,8 d的吸水率从2.5%降低为1.6%,表面接触角从78.5°增加到82.1°,800℃时的残炭率从21.1%提高到29.5%。

  13. 水洗-烘焙联合预处理对稻壳微波热解产品特性的影响%Effect of combining washing and torrefaction pretreatment on properties of product from microwave-induced pyrolysis of rice husk

    张理; 张书平; 董庆; 熊源泉


    预处理技术能提高生物质热解产物的品质.本文研究了水洗-烘焙联合预处理技术对稻壳微波热解的产物特性的影响,结果表明:水洗-烘焙联合预处理技术增加了固体产率,而减少了液体和气体的产率;联合预处理技术提高了稻壳微波热解气体产物的品质,气体产物中CO2含量减少,CH4和H2的含量增加,气体产物的热值提高到13MJ/m3;联合预处理技术提高了稻壳微波热解液体产物的品质,增大了液体产物中苯酚类和糖类的含量,减少了液体产物中酸的含量,简化了液体产物的成分.%Pretreatment can improve the qualities of biomass pyrolysis products. This study investigated the effect of combining washing and torrefaction methods on properties of product from microwave- induced pyrolysis of rice husk. It was found that combining washing and torrefaction pretreatment could increase the yields of solid,but decrease the yields of liquid and gas from microwave-induced pyrolysis. The product qualities of liquid and gas were improved by pretreatment,the gas products contained more concentrated H2 and CH4 with higherLHV up to 13MJ/m3,the liquid products contained more concentrated phenols and sugars with less acids content,and the compounds in liquid were simplified by combining washing and torrefaction pretreatment.

  14. Energy Utilization and Environmental Aspects of Rice Processing Industries in Bangladesh

    Mohammed Ahiduzzaman


    Full Text Available In this study, the energy utilization and environmental aspects of the rice processing industries in Bangladesh was analyzed. Rice husk, a milling by-product of rice, is used as a source of thermal energy to produce steam for parboiling of raw rice. The rice is mostly dried on a concrete floor under the sunshine. In mechanical drying, rice husks are used as a source of primary energy. In Bangladesh, the annual estimated energy used in 2000 for the drying of rice by sunshine was 10.7 million GJ and for drying and parboiling by rice husks it was 48.2 million GJ. These amounts will increase to 20.5 and 92.5 million GJ in 2030, respectively. Electrical energy consumption for mechanical drying and milling of rice was calculated as 1.83 million GJe and 3.51 million GJe in 2000 and in 2030, respectively. Biogenic carbon dioxide emission from burning of rice husk is renewed every year by the rice plant. Both the biogenic and non-biogenic carbon dioxide emissions in 2000 were calculated as 5.7 and 0.4 million tonnes, respectively, which will increase to 10.9 and 0.7 million tonnes in 2030. The demand of energy for rice processing increases every year, therefore, energy conservation in rice processing industries would be a viable option to reduce the intensity of energy by increasing the efficiency of rice processing systems which leads to a reduction in emissions and an increased supply of rice husk energy to other sectors as well.

  15. Antimicrobial activity of fermented Theobroma cacao pod husk extract.

    Santos, R X; Oliveira, D A; Sodré, G A; Gosmann, G; Brendel, M; Pungartnik, C


    Theobroma cacao L. contains more than 500 different chemical compounds some of which have been traditionally used for their antioxidant, anti-carcinogenic, immunomodulatory, vasodilatory, analgesic, and antimicrobial activities. Spontaneous aerobic fermentation of cacao husks yields a crude husk extract (CHE) with antimicrobial activity. CHE was fractioned by solvent partition with polar solvent extraction or by silica gel chromatography and a total of 12 sub-fractions were analyzed for chemical composition and bioactivity. CHE was effective against the yeast Saccharomyces cerevisiae and the basidiomycete Moniliophthora perniciosa. Antibacterial activity was determined using 6 strains: Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis (Gram-positive) and Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella choleraesuis (Gram-negative). At doses up to 10 mg/mL, CHE was not effective against the Gram-positive bacteria tested but against medically important P. aeruginosa and S. choleraesuis with a minimum inhibitory concentration (MIC) of 5.0 mg/mL. Sub-fractions varied widely in activity and strongest antibacterial activity was seen with CHE8 against S. choleraesuis (MIC of 1.0 mg/mL) and CHE9 against S. epidermidis (MIC of 2.5 mg/mL). All bioactive CHE fractions contained phenols, steroids, or terpenes, but no saponins. Fraction CHE9 contained flavonoids, phenolics, steroids, and terpenes, amino acids, and alkaloids, while CHE12 had the same compounds but lacked flavonoids.

  16. Organic Compounds in Silica Bodies of Rice Revealed by X-ray Microanalysis and Micro-infrared Spectroscopy

    MA Xue-long; FANG Jiang-yu


    To understand the possible mechanism controlling the formation of silicon bodies in higher plants, we need to know the nature of organic compounds associated with silicon bodies and induces silicon precipitation in plant cells. A new method was developed to isolate pure silicon body in fresh leaves of rice (Oryaa sativa L. Var. 297) at low temperature by grinding and centrifugation procedures, which avoided degradation of organic molecules induced by high temperature and strong oxidizing acids used in the traditional method. The energy dispersive X-ray spectrum under scanning electron microscope showed that there was a great amount of carbon in silicon bodies in addition to silicon and oxygen. Organic compounds intimately associated with silicon bodies were released by treatment with HF solution. Analysis of the organic compounds by micro-infrared spectroscopy revealed the presence of polyphenol and polysaccharide and a little protein.

  17. Characteristics of Portland blast-furnace slag cement containing cement kiln dust and active silica

    A. Abdel Rahman


    Full Text Available This investigation dealt with the effect of active silica, silica fume (SF or rice husk ash (RHA, on the mechanical and physico-chemical characteristics of the hardened blended cement pastes made of Portland blast-furnace slag cement (PSC containing cement kiln dust (CKD cured under normal conditions. Two blends made of PSC and CKD, improved by SF and two blends made of PSC and CKD improved by RHA were investigated. Hardened blended cement pastes were prepared from each cement blend by using water/cement ratio (W/C of 0.30 by weight and hydrated for various curing ages of 1, 3, 7, 28 and 90 days at the normal curing conditions under tap water at room temperature. Each cement paste was tested for its physico-chemical and mechanical characteristics; these characteristics include: compressive strength and kinetics of hydration. The phase composition of the formed hydration products was identified using X-ray diffraction (XRD and differential thermal analysis (DTA. It was found that the partial substitution of PSC by 10% and 15% of CKD is associated with an increase in the rate of hydration and a subsequent improvement of compressive strength of hardened PSC–CKD pastes. In addition, the replacement of PSC, in PSC–CKD blends, by 5% active silica was accompanied by further improvement of the physico-mechanical characteristics of the hardened PSC–CKD pastes.

  18. Thermal, structural and morphological properties of High Density Polyethylene matrix composites reinforced with submicron agro silica particles and Titania particles

    Oluyemi O. Daramola


    Full Text Available HDPE—based composites samples filled with 2, 4, 6, 8 and 10 wt.% submicron agro-waste silica particles extracted from rice husk ash (RHA at constant 0.3 wt.% Titania loading were prepared using rapra single screw extruder at temperature of 200–230 °C. The extrudates were compressed with a laboratory carver press at a temperature of 230 °C for 10 min under applied pressure of 0.2 kPa and water cooled at 20 °C min−1. Thermal, structural and morphological properties of the composites were studied. The results of the thermogravimetric analysis (TGA revealed that the composites with 10 wt.% SiO2 have the best maximum thermal degradation temperature of 438.73 °C. The crystal structure of neat HDPE, and the siliceous composites developed revealed two obvious diffractive peaks of about 21.3° and 23.7° corresponding to typical crystal plane (1 1 0 and (2 0 0 of orthorhombic phase respectively. The diffractive peaks do not shift with the addition of silica particles; this clearly indicates that the addition of silica particles did not exert much effect on the crystalline structure of HDPE. There is no much difference in the interplanar distance (d-value. Lamellar thickness (L of HDPE increases with the addition of silica particles, which implies that silica particles aid the formation of more perfect crystals. Scanning electron microscopy studies indicated that there were chains inter diffusion and entanglement between HDPE matrix and the silica particles at lower weight fraction (2–4 wt.% of submicron silica particles which resulted into homogeneous dispersion of the particles within the matrix.

  19. Sorghum husk biomass as a potential substrate for production of cellulolytic and xylanolytic enzymes by Nocardiopsis sp. KNU.

    Kshirsagar, Siddheshwar D; Bhalkar, Bhumika N; Waghmare, Pankajkumar R; Saratale, Ganesh D; Saratale, Rijuta G; Govindwar, Sanjay P


    Nocardiopsis sp. KNU was found to degrade various lignocellulosic waste materials, namely, sorghum husk, sugarcane tops and leaves, wheat straw, and rice husk very efficiently. The strain was found to produce high amounts of cellulase and hemicellulase. Augmentation of cotton seed cake as an organic nitrogen source revealed inductions in activities of endoglucanase, glucoamylase, and xylanase up to 70.03, 447.89, and 275.10 U/ml, respectively. Nonionic surfactant Tween-80 addition was found to enhance the activity of endoglucanase enzyme. Cellulase produced by Nocardiopsis sp. KNU utilizing sorghum husk as a substrate was found to retain its stability in various surfactants up to 90%. The produced enzyme was further tested for saccharification of mild alkali pretreated rice husk. The changes in morphology and functional group were analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy. Enzymatic saccharification confirmed the hydrolytic potential of crude cellulase. The hydrolysate products were analyzed by high-performance thin layer chromatography.

  20. A Planning Experimental Investigation on Tobacco Leaves Dryer Using Paddy Husk and Coal

    Huy Bich Nguyen


    Full Text Available In Viet Nam, the drying technology and techniques for tobacco leaves is one of the most difficulties and plays as key point to get high economic efficiency in tobacco production. To drying for tobacco leaves of 3,500 hectare, for example in Gia Lai province, there needs about 3000 dryers and there is more than 100,000 cubic meter of wood have been burned for drying which equivalent to more than 300 hectare of forest is deforested annually. A designing and manufacturing study for new tobacco dryer to replace the wood fuel by paddy-husk or coal-wood has been implemented. The results indicate that the new dryer using rice-husk or coal can be replaced for the actual drying system used fire wood with the high quality of tobacco leaves and high efficiency. The planning experimental investigation has found the function of the rate of energy consumption and the quality of drying products successful

  1. Synthesis of carbon nanoparticles from waste rice husk used for the optical sensing of metal ions%废米糠制备炭纳米颗粒及其对金属离子的光学传感性能

    Peggy Zhen Zhen Ngu; Stephanie Pei Phing Chia; Jessica Fung Yee Fong; Sing Muk Ng


    以废米糠为原料,浓硫酸为脱水剂,通过炭化法制备出炭纳米颗粒( CNPs),探讨CNPs荧光发射特征、金属离子的淬灭效应以及作为Sn(II)离子传感材料应用。 CNPs产率最佳条件为:硫酸浓度12 mol/L、加热温度120℃及恒温时间30 min。样品在水中强蓝光的最大发射波为439 nm。通过加入金属离子,使金属离子与CNPs表面间形成复合物而淬灭荧光。 Sn(II)离子对CNPs荧光具有显著的淬灭效应。 Sn(II)离子浓度对淬灭效应符合Stern-Volmer线性关系,Sn(II)离子为6.13 mmol/L。 Sn(II)离子的检测限为18.7μmol/L。%This work reports on a synthesis of carbon nanoparticles ( CNPs) from waste rice husk by thermally-assisted carboniza-tion in the presence of concentrated sulfuric acid. The fluorescent emmision characteristics of the CNPs, their quenching effects by metal ions and their use as a sensing material for Sn( II) ions were investigated. Results indicated that the yield of CNPs was opti-mized at a sulphuric acid concentration of 12 mol/L, heating temperature of 1 200 ℃ and heating time of 30 min. The sample showed a strong blue luminescence in water with a maximum emission at 439 nm. The fluorescence can be quenched by adding vari-ous metal ions by the formation of complexes between the metal ions and surface of the CNPs. Sn( II) ions had the most significant quenching effect on the fluorescence of the CNPs, which is concentration-dependent. The concentration dependent quenching was linearized with the Stern-Volmer equation, and showed a linear response up to a Sn(II) concentration of 6. 13 mmol/L. The limit of detection for Sn(II) ions is 18. 7 μmol/L with good repeatability.

  2. Casca de arroz e palhada de soja na compostagem de carcaças de frangos de corte - doi: 10.4025/actascianimsci.v33i1.10824 Rice husks and soy straw as substrate for composting of broiler carcasses - doi: 10.4025/actascianimsci.v33i1.10824

    Arlei Coldebella


    Full Text Available Avaliou-se a atuação da casca de arroz e da palhada de soja como substrato para compostagem de carcaça de frangos de corte, observando a degradação dos dois substratos e das carcaças pelo monitoramento da temperatura, peso das carcaças e dos substratos e análise físico-química do produto final. As câmaras foram montadas com carcaças de 10 aves recém abatidas, com quatro repetições no tempo. Instalou-se em cada câmara um termopar para registro da temperatura. O substrato e as carcaças foram pesadas separadamente, no início, aos 15 e aos 30 dias de compostagem. Ao final de cada período, foram realizadas análises físico-química de amostras de cada câmara, avaliando-se o pH e os teores de matéria seca, cinzas, P, N, K, Cu, Zn, Mn, Fe e carbono orgânico. Concluiu-se que a palhada de soja pode ser usada como alternativa para substrato de compostagem de carcaças de aves, atendendo à relação C/N exigida pela legislação ao final da terceira reutilização. A casca de arroz, da mesma forma, pode ser utilizada na compostagem de carcaças de aves, porém reutilizada por maior número de vezes. A decomposição das carcaças foi significativamente maior, em percentual, na palhada de soja ao final do quarto período de compostagem (p ≤ 0,05.The performance of rice husks and of soy straw were evaluated as substrate for on-farm poultry carcass composting, observing the degradation of the two substrate and of the carcasses through monitoring the temperature, weight of the carcasses and of the substrate and physiochemical analysis of the final product. The piles were arranged with carcasses of 10 recently slaughtered birds, with four repetitions in time. A thermo pair was installed in each pile to register the temperature. The substrate and the carcasses were weighed separately, in the beginning, day 15 and day 30 of composting. At the end of each period, the physiochemical analysis of samples were made from each pile, evaluating

  3. Effects of temperature and oxygen content on Hg0 oxidation and adsorption by rice husk char impregnated with NH4Br%温度和氧含量对NH4Br改性稻壳焦汞氧化吸附特性的影响

    姚婷; 段钰锋; 朱纯; 周强; 佘敏; 陈亚南


    采用10 g·L−1 NH4Br溶液对原始稻壳焦进行浸渍改性制备了脱汞吸附剂。利用比表面积及孔隙度分析仪、扫描电子显微镜/X射线能谱分析仪对改性前后稻壳焦吸附剂物理化学性质进行表征。在固定床汞吸附实验台上对吸附剂床层出口元素汞(Hg0)和二价汞(Hg2+)进行同步检测,研究了不同温度下N2气氛和N2+6.4%(体积) O2气氛中改性稻壳焦的汞氧化吸附特性。50℃下N2气氛、N2+6.4%(体积)O2气氛以及150℃下N2气氛中固定床出口均未明显检测到Hg2+,50℃和150℃时脱汞率均可达90%。温度为150℃时,在N2+6.4%(体积)O2气氛中吸附剂的总汞(HgT)脱除效率为98.2%,其中82.2%的Hg0被吸附脱除,其余则被O2非均相氧化为Hg2+而氧化脱除。通过对程序升温管式炉出口 HgT进行检测研究了吸附剂表面吸附态汞的脱附特性。汞脱附峰值温度300℃表明吸附态汞可能以Hg-Br化合物的形式赋存于改性稻壳焦表面,220~350℃的脱附温度说明吸附态汞有较高的热稳定性。100.14%~118.62%的汞平衡率验证了实验结果的准确性。%The mercury sorbent was prepared from raw rice husk char impregnated with 10 g·L−1 NH4Br solution. The physical-chemical characteristics of sorbents before and after modification were analyzed by surface area and porosity analyzer, scanning electron microscopy and X-ray energy dispersive spectroscope. The mercury oxidation and adsorption performance of the modified sorbents were investigated by analyzing mercury speciation (Hg0 and Hg2+) in the outlet of a fixed bed reactor system in N2 and N2+6.4%(vol)O2 atmosphere at different temperatures. No obviousHg2+ was detected in N2, N2+6.4%(vol)O2 atmosphere at 50℃ and N2 atmosphere at 150℃. Modified rice husk char exhibited a mercury removal efficiency of 90% at 50℃ and 150℃. Total mercury (HgT) removal efficiency of 98.2% was obtained in N2+6.4%(vol)O2


    李燕孙; 成岳; 苏晓渊; 潘顺龙; 冯茂华; 江舟



  5. Persistence and metabolism of imidacloprid in rice.

    Akoijam, Romila; Singh, Balwinder


    Imidacloprid is a systemic insecticide which gives effective control of plant and leaf hoppers in rice. The persistence and metabolism of imidacloprid in paddy leaves, rice grains, bran, straw and husk were studied following two applications of imidacloprid (Confidor 17.8 SL) @ 20 and 80 g a.i. ha(-1) at an interval of 10 days. Samples of paddy leaves were collected at various time intervals. The samples of rice grains, bran, straw and husk were collected at the time of harvest. The limit of quantification of imidacloprid and its metabolites was worked out to be 0.01 mg kg(-1). The maximum residues of imidacloprid and its metabolites in paddy leaves after 0 day (1 h after last spray) of its application @ 20 and 80 g a.i. ha(-1) were found to be 4.57 and 13.94 mg kg(-1), respectively. These residues could not be detected after 60 and 90 days following last application of imidacloprid at lower and higher dosages, respectively. In rice, olefin metabolite was found to be the main constituent, followed by nitroguanidine, urea, 5-hydroxy, chloronicotinic acid and nitrosimine. The samples of rice grains, bran, straw and husk did not reveal the presence of imidacloprid or its metabolites following its application at both the dosages at harvest.

  6. 纳米SiO2对水稻稻瘟病的抗病效应及对水稻生长发育的影响%Effects of Nano-silica on Rice's Resistance to Magnaporthe oryzae and on Rice Growth

    刘俊渤; 常海波; 马景勇; 唐珊珊; 齐静芝


    Using nano-silica as silicon source, disease-resistant varieties "NongDa 18" and susceptible varieties "Mongolian rice" as material, the experiment determined the role of the nano-silica on rice's resistance to magnaporthe grisea and its effect on rice growth. The results show that the disease indexes of the disease-resistant varieties and susceptible varieties with nano-silica treatment respectively decreased by 30.98% and 51.03% compared with those without silicon processing. The relative control effect of disease-resistance varieties achieved 54.93% , while the susceptible varieties reached 73.47% . Silicon application reduced the disease level and index, strengthened the resistance to rice blast, particularly among the susceptible Mongolian rice. Nano-silica application to rice can not only significantly improve the content of chlorophyll, the net photosynthetic rate, stomatal conductance and intercellular carbon dioxide concentration, which help to enhance the photosynthesis of rice leaf, but can also increase the number of new roots and its longest length and improve the active absorption area and the vigor of roots. At the same time, it can also increase the contact angle of rice leaves and reduce the leaf angle and the attachment of fungi. In short, it is good for normal rice growth.%以纳米SiO2为硅源,以抗稻瘟病的水稻品种“农大18号”和感稻瘟病的水稻品种“蒙古稻”为材料,测定了纳米SiO2对水稻抗瘟效应及水稻生长发育的影响.试验结果表明:纳米SiO2处理的抗病品种和感病品种的病情指数分别比不施硅处理下降了30.98%和51.03%,抗病品种的相对防治效果达到了54.93%,而感病品种的相对防治效果达到了73.47%.施硅减轻了病级和病情指数,增强了水稻对稻瘟病的抗性,在感病品种“蒙古稻”上表现尤为明显.水稻在施用纳米SiO2后,不仅可显著提高叶片叶绿素含量,增大叶片净光合速率、气孔导度和胞间CO2

  7. Synthesis of magnesium silicate from wheat husk ash: Effects of parameters on structural and surface properties

    Pinar Terzioglu


    Full Text Available In the present study, magnesium silicate was produced by using wheat husk ash. Wheat husk was burned at 600 °C to obtain an amorphous ash structure, and the ash was processed with sodium hydroxide solution with heat to extract silica. Sodium silicate solution and magnesium salts were used to synthesize magnesium silicate. The present study investigates effects of the feeding rate on magnesium silicate production (0.6 mL/min, 35 mL/min, 70 mL/min, the type of magnesium salt (MgSO4 • 7H2O or MgCl2 • 6H2O, temperature (25 °C or 50 °C, and the washing agent (water and acetone on the chemical composition and surface characteristics of magnesium silicate. The results demonstrated that all of the variables affected the surface characteristics of magnesium silicate, such as surface area, particle size, and pore volume. However, it was also observed that the studied parameters did not affect the chemical composition of magnesium silicate. The wheat husk ash-based magnesium silicates obtained in the experimental study had a BET surface area ranging from 79 to 91 m2/g and a particle size varying from 42 to 63 µm.

  8. Comparative utilization of biodegraded and undegraded rice husk in ...



    Apr 6, 2009 ... the use of RH in monogastric animals feed production because of its fibre ... The effects of raw and fermented RH on performance, nutrient utilization ..... mycotoxin in the fermented PKM as confirmed by Lim et al. (2001) from ...

  9. Characterization of hydrochars produced by hydrothermal carbonization of rice husk

    Kalderis, D.; Kotti, M. S.; Méndez, A.; Gascó, G.


    Biochar is the carbon-rich product obtained when biomass, such as wood, manure or leaves, is heated in a closed container with little or no available air. In more technical terms, biochar is produced by so-called thermal decomposition of organic material under limited supply of oxygen (O2), and at relatively low temperatures (heating values and heavy metal content. The surface area was low for all hydrochars, indicating that porous structure was not developed during treatment. The hydrochar obtained at 300 °C and 6 h residence times showed a predicted higher heating value of 17.8 MJ kg-1, a fixed carbon content of 46.5% and a fixed carbon recovery of 113%, indicating a promising behaviour as a fuel.




    Nov 20, 2013 ... nitrogenous fertilizer hence, higher yield (Hu, 1993). Later came the high yielding .... Rice lines ZAU11S106 and control ZAU11F121 were sown on May. 14th in nine rows each ... release the pollen cells. Anther-husks were ...

  11. Compost maturity and nitrogen availability by co-composting of paddy husk and chicken manure amended with clinoptilolite zeolite.

    Latifah, Omar; Ahmed, Osumanu Haruna; Susilawati, Kassim; Majid, Nik Muhamad


    The availability of paddy husk from rice processing plants remains high owing to increase in the worldwide rice consumption. Increasing demand for chicken products leads to poultry wastes production. Co-composting of the aforementioned wastes could solve the indiscriminate disposal of these wastes. Thus, co-composting of paddy husk and chicken slurry with clinoptilolite zeolite and urea as additive was carried out. Clinoptilolite zeolite was used to enhance ammonium and nitrate retention in the compost. Temperature of the compost was monitored three times daily for 55 days. Cation exchange capacity, organic matter, ash, humic acids, pH, total C, N, C/N ratio; total P, exchangeable Ca, Mg, K, NH4+, NO3-, and heavy metals contents were determined using standard procedures. pH, total N, humic acids, ash, NH4+, NO3-, P, Ca, Mg, and K contents increased but the salinity, heavy metals contents, and microbial population were low after the co-composting process. Zea mays L. (test crop) seed germination rate in distilled water and the compost were not significantly different. Growth of Spinach oleracea (test crop) on a peat-based growing medium and the compost was also not significantly different. These findings were possible because the clinoptilolite zeolite used in co-composting reduced accumulation of heavy metals that may have damage effects on the test crops. Mature compost with good agronomic properties can be produced by co-composting chicken slurry and paddy husk using clinoptilolite zeolite and urea as additives.

  12. Screening of Fungal Strains Grown in Solid-state Culture for Production of Pectinase from Coffee Husk

    Na Thi Ty Ngo


    Full Text Available Eighty percent of Vietnamese coffee production can be found in Central Highlands (Tay Nguyen. This paper describes a screening of fungi strains isolated from coffee husk waste collected in Dak Lak province, Tay Nguyen, for pectinase production. It was found that 17 different fungi strains were isolated from samples of 11 coffee farms. Among them. there were only 9 trains which could hydrolyze pectin. The diameter of the hydrolysis halo around fungi colonies in Pectinase Screening Agar Medium (PSAM was measured as an indicator to assess the pectinase activity. Phylogenetic analysis based on 28S rRNA gene sequences showed that detected Rhizopus oryzae. Aspergillus oryzae and Hypocrea pseudokoningii were those giving the largest holo zones. Hypocrea pseudokoningii presented the best pectinase activity of 657.16 UI/g and was chosen for biomass production to collect enzyme. In a further study, effect of rice bran addition to coffee husk and moisture of culture medium on the spore yield of Hypocrea pseudokoningii were investigated. Using coffee husk medium with 23% rice bran addition and 65% moisture at ambient temperature, the highest spore yield of 9.2 x108 spores/g was found after incubation for 168 hours. The fungi biomass product was dried at 40oC for 54 hours to obtain the final moisture of 12% and spore survival of 5.9 x108 spores/g.  

  13. Bioethanol production from coconut husk fiber

    Mirelle Márcio Santos Cabral

    Full Text Available ABSTRACT: Population growth and the increasing search for healthy foods have led to a major consumption of coconut water and, hence, to an environmental impact caused by the inappropriate disposal of green coconut husks. This lignocellulosic biomass has deserved attention of researchers concerning the seeking of new usages, as, for example, in renewable fuels production technologies. This study examines the potential of green coconut husk fibers as a feedstock for the production of bioethanol. The coconut fibers were pretreated through an alkaline method, hydrolyzed enzymatically and submitted to ethanol fermentation with commercial yeasts of Saccharomyces cerevisiae. Despite the significant loss of cellulose (4.42% in relation to the fiber and 17.9% concerning the original cellulose content, the alkaline pretreatment promoted an efficient solubilization of lignin (80%, turning the coconut fibers into a feasible raw material for 2G ethanol production studies. Enzymatic hydrolysis converted 87% of the sugars and the ethanolic fermentation consumed 81% of the substrate in the hydrolyzate, leading to a sugar to ethanol convertion efficiency of 59.6%. These results points out that green coconut husks are a promising alternative to the production of renewable energy.

  14. Bioethanol produced from Moringa oleifera seeds husk

    Ali, E. N.; Kemat, S. Z.


    This paper presents the potential of bioethanol production from Moringa oleifera seeds husk which contains lignocellulosic through Simultaneous Saccharification and Fermentation (SSF) process by using Saccharomyces cerevisiae. This paper investigates the parameters which produce optimum bioethanol yield. The husk was hydrolyzed using NaOH and fermented using Saccharomyces cerevisiae yeast. Batch fermentation was performed with different yeast dosage of 1, 3, and 5 g/L, pH value was 4.5, 5.0 and 5.5, and fermentation time of 3, 6, 9 and 12 hours. The temperature of fermentation process in incubator shaker is kept constant at 32ºC. The samples are then filtered using a 0.20 μm nylon filter syringe. The yield of bioethanol produced was analysed using High Performance Liquid Chromatography (HPLC). The results showed that the highest yield of 29.69 g/L was obtained at 3 hours of fermentation time at pH of 4.5 and using 1g/L yeast. This research work showed that Moringa oleifera seeds husk can be considered to produce bioethanol.


    Didi Dwi Anggoro; Aprilina Purbasari


    Rice husk is the milling byproduct of rice and is a major waste product of the agriculture industry. Amorphous silica, commonly referred to as rice husk ash, was extracted from rice husk by acid leaching, pyrolysis, and carbon-removing processes. These properties make the ash a valuable raw material for many industries.  This paper is study of synthesized of zeolite Y from rice husk ash. Zeolite Y synthesis is used for petroleum industry as expensive catalyst. Rice husk was calcined at t...


    Nuran TAŞLIGİL


    Full Text Available Rice is one of the staple foods in the world. Rice in the husk is a cereal whose breeding depends on a special access because of the climate it needs can create a malaria epidemic. Turkey is one of the major countries in rice in the husk breeding. In Turkey, the accretion in the amount of the rice for each person especially after 1980, caused an accretion in the export of the notch. As a matter of fact, the production and the breeding of the notch changes every year acording to the economy, ecology and the marketing channels. However, according to the last istatistics it has been understood that the rice plantation areas in Marmara Region and Edirne showed distinction among the whole country.

  17. Incorporation of hazelnut shell and husk in MDF production.

    Cöpür, Yalçin; Güler, Cengiz; Taşçioğlu, Cihat; Tozluoğlu, Ayhan


    Hazelnut shell and husk (Coryllus arellana L.) is an abundant agricultural residue in Turkey and investigating the possibilities of utilizing husk and shell in panel production might help to overcome the raw material shortage that the panel industry is facing. The aim of this work was to investigate the possibilities of utilizing hazelnut shell and husk in medium density fiberboard (MDF) production. To produce general purpose fiberboards, fiber-husk and fiber-shell mixtures at various percentages were examined in this study. The results indicated that panels could be produced utilizing hazelnut husk up to 20% addition without falling below the properties required in the standards. Shell addition was restricted up to 10%, because higher addition levels diminished the elastic modulus and internal bond strength below the acceptable level.

  18. Silicate mineral impacts on the uptake and storage of arsenic and plant nutrients in rice ( Oryza sativa L.).

    Seyfferth, Angelia L; Fendorf, Scott


    Arsenic-contaminated rice grain may threaten human health globally. Since H₃AsO₃⁰ is the predominant As species found in paddy pore-waters, and H₄SiO₄⁰ and H₃AsO₃⁰ share an uptake pathway, silica amendments have been proposed to decrease As uptake and consequent As concentrations in grains. Here, we evaluated the impact of two silicate mineral additions differing in solubility (+Si(L), diatomaceous earth, 0.29 mM Si; +Si(H), Si-gel, 1.1 mM Si) to soils differing in mineralogy on arsenic concentration in rice. The +Si(L) addition either did not change or decreased As concentration in pore-water but did not change or increased grain-As levels relative to the (+As--Si) control. The +Si(H) addition increased As in pore-water, but it significantly decreased grain-As relative to the (+As--Si) control. Only the +Si(H) addition resulted in significant increases in straw- and husk-Si. Total grain- and straw-As was negatively correlated with pore-water Si, and the relationship differed between two soils exhibiting different mineralogy. These differing results are a consequence of competition between H₄SiO₄⁰ and H₃AsO₃⁰ for adsorption sites on soil solids and subsequent plant-uptake, and illustrate the importance of Si mineralogy on arsenic uptake.

  19. Compressive Strength and Water Permeability Performance of Micronised Biomass Silica Concrete

    S.H. Adnan


    Full Text Available Concrete is a common material that is widely used in construction industry. Cement is the main material component for producing concrete but its production has lead into CO2 emission. This work presents a study on Micronised Biomass Silica (MBS that can be used as pozzolan material which can enhance the quality of concrete. The material can be produced from a by-product of biomass agricultural waste but for this study rice husk has been used. From the chemical analysis, MBS has a chemical composition that is fulfill the standard requirement for becoming pozzolan material. The result of MBS concrete shows that the MBS material can enhance the performance of concrete by increasing the compressive strength development and reducing the water permeability. The drawback of MBS is the workability of fresh concrete but can be rectify by using superplasticizer. By replacing up to 12% of cement, MBS material gives the highest performance in term of strength and permeability of the concrete.

  20. Preparation of RHA-silica/graphene oxide nanocomposite for removal of nickel ions from water

    Tien, Tran Thi Thuy; Tu, Tran Hoang; Thao, Huynh Nguyen Phuong; Hieu, Nguyen Huu


    In this study, silica was synthesized from rice husk ash (RHA-SiO2) by precipitation method. Graphene oxide (GO) was prepared by modified Hummers method. RHA-SiO2/GO nanocomposite was fabricated by in-situ one-step method using 3-Aminopropyltriethoxysilane (APS) as a coupling agent. The nanocomposite was characterized by using X-ray Fluorescence, X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) specific surface area. The adsorption of RHA-SiO2/GO for Ni2+ ions from water was investigated and compared with the precursors. Ultraviolet-visible (UV-Vis) spectroscopy was used to quantify the amount of the initial and the residual Ni2+ concentration. The maximum adsorption capacity of the nanocomposite for Ni2+ calculated from Langmuir isotherm model, which was 256.4 mg/g. In addition, the adsorption data were well-fitted to the pseudo-second-order kinetic equation. Accordingly, this study demonstrated that RHA-SiO2/GO could be used as a highly efficient adsorbent for removal Ni2+ ions from aqueous solution.


    Gatot Siswo Hutomo


    Full Text Available EKSTRAKSI SELULOSA DARI POD HUSK KAKAO MENGGUNAKAN SODIUMHIDROKSIDA Cellulose Extraction from Cacao Pod Husk Using Sodium Hydroxide Gatot Siswo Hutomo, Djagal Wiseso Marseno, Sri Anggrahini, Supriyanto ABSTRAK Pod husk kakao banyak mengandung komponen kimia seperti pektin, lignin, hemiselulosa dan selulosa serta beberapakomponen yang lain yaitu caffein dan theobromine. Khusus selulosa dapat dilakukan modiÞ kasi sebagai turunanselulosa yang mempunyai banyak fungsi serta dapat diaplikasikan untuk pangan. Penelitian ekstraksi selulosa dari podhusk kakao telah dilakukan. Tujuan penelitian ini adalah untuk memperoleh konsentrasi sodium hidroksida sebagaibahan untuk ekstraksi selulosa dari pod husk kakao. Selulosa pada pod husk kakao terikat sangat kuat dengan lignin,sodium hidroksida akan memutus dengan baik ikatan antara selulosa dengan lignin. Bleaching pada selulosa jugadilakukan dengan menggunakan sodium hipoklorida 3% dan sodium bisulÞ t 3% untuk meningkatkan lightness. SpektraFT-IR dan X-ray juga dilakukan untuk pendeteksian pada selulosa hasil ekstraksi. Hasil ekstraksi selulosa dari pod huskkakao menggunakan sodiumhidroksida 12% menghasilkan rendemen sekitar 26,09% (db dengan kristalinitas 27,14%,kadar abu 6,56% (db, WHC 5,87 g/g dan OHC 2,74 g/g. Dapat disimpulkan bahwa sodium hidroksida 12% adalahkonsentrasi yang paling baik untuk mengekstraksi selulosa dari pod husk kakao.Kata kunci: Selulosa, pod husk, kakao, ekstraksi ABSTRACT Cacao pod husk contains some compounds like pectin, lignin, hemicelluloses and cellulose, and other compounds suchas caffeine and theobromine. Especially for cellulose should be modiÞ ed as derivates which it have multi functionsin food application. Extraction cellulose from pod husk cacao was investigated. The aim of the research was to Þ ndthe concentration of sodium hydroxide for cellulose extraction from pod husk cacao. Bleaching for cellulose werecarried out twice using sodium hypochlorite 3% (oxydator and

  2. Physicochemical Characterization of various Vietnamese Biomass Residue-derived Biochars (wood, bamboo and risk husk)

    Nguyen, Hien


    This study compares the physico-chemical characteristics of various biocchars produced from biomass residues in Vietnam such as fired wood, rice husk, and bamboo. Wood biochar (WBC), rice husk biochar (RHBC), and bamboo biochar (BBC) were produced under limited oxygen conditions using equipment available locally in Vietnam, known as a Top-Lift Updraft Drum (TLUD). The three biochars are alkaline with pH around 10, but were found to have quite significantly different physico-chemical characteristics. Surface areas (measured by BET) were found to be very significantly higher for WBC and BBC with 479.34 m2/g and 434.53 m2/g, respectively, compared to RHBC (3.29 m2/g). The SEM images correspond with the BET surface area, showing a smooth surface for RHBC, a hollow surface for BBC, and a rough surface for WBC. Total carbon (TC) of WBC and BBC are above 80%, while RHBC has only 47.95% TC. Despite having different TC, the content of hydrogen among the biochars is similar, ranging from 2.07% to 2.34%, and the ratio of H/C also follows the same trend. Thus, although the biochars are produced by the same method, the various feedstocks lead to different physico-chemical properties. Ongoing work is linking these physico-chemical properties to fertiliser efficiencies in terms of nitrate and ammonia adsorption and retention capacities, in order to design optimal biochar properties for use in fertilisation. Key words: physico-chemical characteristic, biochar, surface area, SEM, total carbon, feedstock

  3. Process for production of high density/high performance binderless boards from whole coconut husk: Part 2: Coconut husk morphology, composition and properties

    Dam, van J.E.G.; Oever, van den M.J.A.; Keijsers, E.R.P.; Putten, van der J.C.; Anayron, C.; Josol, F.; Peralta, A.


    For production of compression moulded boards from whole coconut husk the auto-adhesive properties are derived from the intrinsic high lignin content. Since the properties of manufactured boards for a large part will depend on the input husk material these properties are studied here. Husks of differ

  4. Pyrolysis kinetics of hazelnut husk using thermogravimetric analysis.

    Ceylan, Selim; Topçu, Yıldıray


    This study aims at investigating physicochemical properties and pyrolysis kinetics of hazelnut husk, an abundant agricultural waste in Turkey. The physicochemical properties were determined by bomb calorimeter, elemental analysis and FT-IR spectroscopy. Physicochemical analysis results showed that hazelnut husk has a high calorimetric value and high volatile matter content. Pyrolysis experiments were carried out in a thermogravimetric analyzer under inert conditions and operated at different heating rates (5, 10, 20°C/min). Three different kinetic models, the iso-conversional Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) models and Coats-Redfern method were applied on TGA data of hazelnut husk to calculate the kinetic parameters including activation energy, pre-exponential factor and reaction order. Simulation of hazelnut husk pyrolysis using data obtained from TGA analysis showed good agreement with experimental data. Combining with physicochemical properties, it was concluded that this biomass can become useful source of energy or chemicals.


    Khusid S. B.; Gneush A. N.; Nesterenko E. E.


    The article describes the results of the complex feed additive based on sunflower husk, enriched with beer wort with the addition of pumpkin pulp. We have studied the chemical composition of sunflower husk, which is the secondary resource of the processing plant raw material, selected methods of enrichment of this raw material with the help of fungi Trichoderma harzianum. Cellulolytic enzyme preparations on the basis of fungi of the genus Trichoderma for use in agriculture and animal feed pro...

  6. Coconut husk-fueled pilot plant put to test


    A pilot electric-power plant, running on coconut husks, was successfully demonstrated in Laguna, Philippines. This 30-kW biomass-fed plant provides electricity for 50 remote households and a wood-carving shop using a motor. The system involves: burning coconut husks to obtain producer gas; filtering this gas and driving a generator with the power of the combusted gas. The village is saving 65 to 75% of their diesel fuel consumption with this system.

  7. Value addition of corn husks through enzymatic production of xylooligosaccharides

    Ashis Kumar Samanta

    Full Text Available ABSTRACT Corn husks are the major wastes of corn industries with meagre economic significance. The present study was planned for value addition of corn husk through extraction of xylan, followed by its enzymatic hydrolysis into xylooligosaccharides, a pentose based prebiotic. Compositional analysis of corn husks revealed neutral detergent fibre 68.87%, acid detergent fibre 31.48%, hemicelluloses 37.39%, cellulose 29.07% and crude protein 2.68%. Irrespective of the extraction conditions, sodium hydroxide was found to be more effective in maximizing the yield of xylan from corn husks than potassium hydroxide (84% vs. 66%. Application of xylanase over the xylan of corn husks resulted into production of xylooligosaccharides with different degree of polymerization namely, xylobiose and xylotriose in addition to xylose monomer. On the basis of response surface model analysis, the maximum yield of xylobiose (1.9 mg/ml was achieved with the enzymatic hydrolysis conditions of pH 5.8, temperature 44°C, enzyme dose 5.7U/ml and hydrolysis time of 17.5h. Therefore, the corn husks could be used as raw material for xylan extraction vis a vis its translation into prebiotic xylooligosaccharides.

  8. Biotechnological potential of coffee pulp and coffee husk for bioprocesses.

    Pandey; Soccol; Nigam; Brand; Mohan; Roussos


    Advances in industrial biotechnology offer potential opportunities for economic utilization of agro-industrial residues such as coffee pulp and coffee husk. Coffee pulp or husk is a fibrous mucilagenous material (sub-product) obtained during the processing of coffee cherries by wet or dry process, respectively. Coffee pulp/husk contains some amount of caffeine and tannins, which makes it toxic in nature, resulting the disposal problem. However, it is rich in organic nature, which makes it an ideal substrate for microbial processes for the production of value-added products. Several solutions and alternative uses of the coffee pulp and husk have been attempted. These include as fertilizers, livestock feed, compost, etc. However, these applications utilize only a fraction of available quantity and are not technically very efficient. Attempts have been made to detoxify it for improved application as feed, and to produce several products such as enzymes, organic acids, flavour and aroma compounds, and mushrooms, etc. from coffee pulp/husk. Solid state fermentation has been mostly employed for bioconversion processes. Factorial design experiments offer useful information for the process optimization. This paper reviews the developments on processes and products developed for the value-addition of coffee pulp/husk through the biotechnological means.

  9. efficacy of rice husk ash against rice weevil and lesser grain borer ...


    Similar numbers of R. dominica progeny were produced in the control, RHAL, and RHAH treatments (78.4, 92.9 and 64.3 .... incubator for an additional 54 days (68 days post-treatment) before ..... Habeeb, G.A. and Mahmud, H.B. 2010. Study.

  10. Accumulation of total mercury and methylmercury in rice plants collected from different mining areas in China.

    Meng, Mei; Li, Bing; Shao, Jun-juan; Wang, Thanh; He, Bin; Shi, Jian-bo; Ye, Zhi-hong; Jiang, Gui-bin


    A total of 155 rice plants were collected from ten mining areas in three provinces of China (Hunan, Guizhou and Guangdong), where most of mercury (Hg) mining takes place in China. During the harvest season, whole rice plants were sampled and divided into root, stalk & leaf, husk and seed (brown rice), together with soil from root zone. Although the degree of Hg contamination varied significantly among different mining areas, rice seed showed the highest ability for methylmercury (MeHg) accumulation. Both concentrations of total mercury (THg) and MeHg in rice plants were significantly correlated with Hg levels in soil, indicating soil is still an important source for both inorganic mercury (IHg) and MeHg in rice plants. The obvious discrepancy between the distribution patterns of THg and MeHg reflected different pathways of IHg and MeHg accumulation. Water soluble Hg may play more important role in MeHg accumulation in rice plants.

  11. Salt dissolution in oil and gas test holes in central Kansas. Part III. Salt dissolution oil and gas test holes in the Chase-Silica Oilfield, Barton and Rice Counties, central Kansas

    Walters, R.F.


    In the 135.3 square mile area of the Chase-Silica Oilfield, Barton and Rice Counties, Kansas, all of the 4,845 oil and gas test holes drilled completely through the Hutchinson Salt Member of the Permian Wellington Formation encountered at depths near 900 feet on the east to near 1000 feet on the west. No salt dissolution takes place after drilling ceases in either cased oil wells or dry holes, however plugged or if plugged at all, because fresh water aquifers in Quaternary and Cretaceous are sealed off by surface casing permanently cemented in place and plugged internally. Exceptions to this statement are three holes where excessive post-drilling salt dissolution caused slow surface subsidence. In the Panning No. 11-A which drilled 90 feet of alluvial sand and gravel, subsidence was followed by 12 hours of sudden dramatic collapse during which the cone shaped hole swallowed a 500-barrel redwood tank, four large concrete rig corners, and all evidence of 190 feet of 10-3/4 inch surface casing cement in place, leaving a circular lake 300 feet in diameter which is still 64 feet deep sixteen years later. These three subsidence areas, studied in detail, involve salt water disposal (SWD) wells moving large volumes (100+ barrels water per hour or 70+ gallons per minute) of corrosive brine, undersaturated as to chlorides, into an excellent outlet reservoir, the Arbuckle dolomite, permitting brine flow across the salt face through casing leaks caused by corrosion. The head differential of about 800 feet plus the gravity drop to 3500 feet provided a tremendous energy input. The 694 remaining oil wells in this 260 million barrel oilfield are nearing depletion; they average only 4.68 barrels of oil per day per well (BOPDPW). With the holes properly plugged as now required under state supervision, it is concluded that no additional areas of surface subsidence will form.

  12. Water-saving technologies affect the grain characteristics and recovery of fine-grain rice cultivars in semi-arid environment.

    Jabran, Khawar; Riaz, Muhammad; Hussain, Mubshar; Nasim, Wajid; Zaman, Umar; Fahad, Shah; Chauhan, Bhagirath Singh


    Growing rice with less water is direly needed due to declining water sources worldwide, but using methods that require less water inputs can have an impact on grain characteristics and recovery. A 2-year field study was conducted to evaluate the impact of conventionally sown flooded rice and low-water-input rice systems on the grain characteristics and recovery of fine rice. Three fine grain rice cultivars-Super Basmati, Basmati 2000, and Shaheen Basmati-were grown under conventional flooded transplanted rice (CFTR), alternate wetting and drying (AWD), and aerobic rice systems. Grain characteristics and rice recovery were significantly influenced by different water regimes (production systems). Poor milling, including the lowest percentage of brown (head) rice (65.3%) and polished (white) rice (64.2-66.9%) and the highest percentage of broken brown rice (10.2%), husk (24.5%-26.3%), polished broken rice (24.7%), and bran (11.0-12.5%), were recorded in the aerobic rice system sown with Shaheen Basmati. With a few exceptions, cultivars sown in CFTR were found to possess a higher percentage of brown (head) and polished (white) rice and they had incurred the least losses in the form of brown broken rice, husk, polished broken rice, and bran. In conclusion, better grain quality and recovery of rice can be attained by growing Super Basmati under the CFTR system. Growing Shaheen Basmati under low-water-input systems, the aerobic rice system in particular, resulted in poor grain characteristics tied with less rice recovery.

  13. Silica Nephropathy

    N Ghahramani


    Full Text Available Occupational exposure to heavy metals, organic solvents and silica is associated with a variety of renal manifestations. Improved understanding of occupational renal disease provides insight into environmental renal disease, improving knowledge of disease pathogenesis. Silica (SiO2 is an abundant mineral found in sand, rock, and soil. Workers exposed to silica include sandblasters, miners, quarry workers, masons, ceramic workers and glass manufacturers. New cases of silicosis per year have been estimated in the US to be 3600–7300. Exposure to silica has been associated with tubulointerstitial disease, immune-mediated multisystem disease, chronic kidney disease and end-stage renal disease. A rare syndrome of painful, nodular skin lesions has been described in dialysis patients with excessive levels of silicon. Balkan endemic nephropathy is postulated to be due to chronic intoxication with drinking water polluted by silicates released during soil erosion. The mechanism of silica nephrotoxicity is thought to be through direct nephrotoxicity, as well as silica-induced autoimmune diseases such as scleroderma and systemic lupus erythematosus. The renal histopathology varies from focal to crescentic and necrotizing glomerulonephritis with aneurysm formation suggestive of polyarteritis nodosa. The treatment for silica nephrotoxicity is non-specific and depends on the mechanism and stage of the disease. It is quite clear that further research is needed, particularly to elucidate the pathogenesis of silica nephropathy. Considering the importance of diagnosing exposure-related renal disease at early stages, it is imperative to obtain a thorough occupational history in all patients with renal disease, with particular emphasis on exposure to silica, heavy metals, and solvents.

  14. Microbially-enhanced composting of wet olive husks.

    Echeverria, M C; Cardelli, R; Bedini, S; Colombini, A; Incrocci, L; Castagna, A; Agnolucci, M; Cristani, C; Ranieri, A; Saviozzi, A; Nuti, M


    The production of a compost from olive wet husks is described. The process is enhanced through the use of starters prepared with virgin husks enriched with selected microbial cultures. This approach, with respect to composting without the use of starters, allows to achieve faster start of the process (10 vs. 45 days), deeper humification (humification rate 19.2 vs. 12.2), shorter maturation time (2 vs. 4-5 months) and better detoxification of the starting material. Furthermore, the compost produced can effectively substitute for turf as a cultivation substrate in horticulture at greenhouse level, with beneficial effects on nutraceutical traits of tomato fruits.


    王明峰; 蒋恩臣; 李伯松; 张强; 许细微; 刘敏; 周岭


    The continuous pyrolysis and secondary cracking performance of rice husk was investigated in a biomass continuous pyrolysis reactor. The effects of pyrolysis temperature, residence time and secondary cracking tempera-ture on pyrolysis products were studied. When rice husk pyrolysis gas composes CO2 and CO mainly, the yield of CO2 reduced and yield of CH4, H2, C2H4, C2H6 increasesd, yield of CO is not much change with pyrolysis temper-ature increasing. Residence time has little effect on the composition of pyrolysis gas. The yield of H2, CH4, C2H4 increases significantly with increasing the temperature of secondary cracking. When secondary cracking temperature is 800℃, production rate of H2 was 12%. Rice husk pyrolysing at 500℃, then cracking at 600℃, acetic acid is as high as 49.44% in the wood vinegar, and acetone and isopropanol are the two more compositions detected in the tar.%在自行研制的生物质连续热解反应装置上进行稻壳连续热解和二次裂解实验研究.随着稻壳热解温度的提高,炭产率降低,气体产率增加,液体产率先增加后减少;随着滞留时间的减少,炭产率、液体产率增加,气体产率减少.稻壳热解气以CO2和CO为主,且二者为竞争关系,热解温度提高,CO2产量降低,CH4、H2、C2H4、C2 H6产量增加,CO的产率变化不大;滞留时间对热解气组分影响不大.二次裂解温度提高,裂解气中的H2、CH4、C2 H4含量明显增加,二次裂解温度为800℃时,H2产率达到12%.稻壳500℃热解挥发物600℃二次裂解木醋液中醋酸含量高达49.44%,焦油中检测到的物质主要为丙酮和异丙醇.

  16. Optimization of silica gel column chromatography extraction process of oryzanol from rice bran oil soap stock by response surface methodology%响应面法优化柱层析工艺提取米糠油皂脚中的谷维素

    沈鸿; 张培培; 庞敏; 姜绍通


    以米糠油加工所得的副产物皂脚为原料,用乙酸乙酯索氏抽提得到皂脚浸提物,采用硅胶柱层析的方法对皂脚浸提物分离纯化谷维素,采用单因素和响应面方法进行优化,确定浸提液的谷维素浓度为4.00%,上样量为8.70 g,硅胶用量为60.00 g。结果表明,此工艺得到的谷维素纯度88.5%,皂脚中谷维素的总提取率达到58.7%。%Soapstock,the byproduct of rice bran oil procossing,was used as raw material. Oryzanol was extracted with ethyl acetate from rice bran oil soap stock and purified by silica gel column chromatography methods. Based on single factor experiments and response surface methodology,the optimum conditions were as follows:oryzanol concentration of sample forsilica gelcolumn chromatography was 4.00%,the sample volume was 8.70 g,the amount of silica gel was 60 g. The results showed that the total extraction rate of oryzanol could reached 58.7% while oryzanol purity was 88.5%.


    Spikelet sterility is the greatest barrier to rice hybridization. ... sterility, Hybridization, Duplicate recessive epis- tasis ' ... hybrid fertility of intra-subspecific crosses, i.e., indica by ..... 'Germ 59(1) 293$ ' ' male sterility and fertility restoration in rice.

  18. Bactericidal activity and silver release of porous ceramic candle filter prepared by sintering silica with silver nanoparticles/zeolite for water disinfection

    Trinh Nguyen, Thuy Ai; Phu Dang, Van; Duy Nguyen, Ngoc; Le, Anh Quoc; Thanh Nguyen, Duc; Hien Nguyen, Quoc


    Porous ceramic candle filters (PCCF) were prepared by sintering silica from rice husk with silver nanoparticles (AgNPs)/zeolite A at about 1050 °C to create bactericidal PCCF/AgNPs for water disinfection. The silver content in PCCF/AgNPs was of 300-350 mg kg-1 determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the average pore size of PCCF/AgNPs was of 50-70 Å measured by Brunauer-Emmett-Teller (BET) method. The bactericidal activity and silver release of PCCF/AgNPs have been investigated by flow test with water flow rate of 5 L h-1 and initial inoculation of E. coli in inlet water of 106 CFU/100 mL. The volume of filtrated water was collected up to 500 L. Results showed that the contamination of E. coli in filtrated water was water was low, far under the WHO guideline of 100 μg L-1 at maximum for drinking water. Based on the content of silver in PCCF/AgNPs and in filtrated water, it was estimated that one PCCF/AgNPs could be used to filtrate of ˜100 m3 water. Thus, as-prepared PCCF/AgNPs releases low content of silver into water and shows effectively bactericidal activity that is promising to apply as point-of-use water treatment technology for drinking water disinfection.

  19. Binderless board and moulded products produced from whole coconut husks

    Dam, van J.E.G.; Snijder, M.H.B.


    A simple and efficient technology has been developed to produce high strength - high density board materials from whole coconut husks, without the addition of chemical binders. The board material has been shown to exhibit excellent properties, which are comparable with or even superior to commercial

  20. Enzymatic hydrolysis of cocoa pod husks. [Trichoderma reesei

    Simpson, B.K.; Oldham, J.H.; Martin, A.M


    Laboratory results are presented of the bioconversion of cellulose from cocoa pod husks, utilizing cellulase from three mutants of Trichoderma reesei. Total reducing sugars in filtered hydrolysates were estimated by the dinitrosalicylic acid method. The sugars present were identified by paper chromatography as glucose and xylose.

  1. [Phytoexclusion potential studies of Si fertilization modes on rice cadmium].

    Chen, Zhe; Tie, Bo-Qing; Lei, Ming; Liu, Xiao-Li; Ye, Chang-Cheng; Luo, Mei-Mei; Mao, Yi-De


    The research used serious situ multi-metal contaminated soils to explore Cd repair potential in rice by adding different kinds of fertilizers, based on the outdoor pot experiment. The experiment was consisted of four treatments including non-used fertilizers (CK), the silicon fertilizer applicated into soil (Tsi), the silicon fertilizer applicated as foliar spray (Ysi) and the silicon fertilizer applicated into soil combined with the foliar spray silicon fertilizer application( Tsi + Ysi). The research examined Cd concentrations in tissues of five key growth periods to reveal cadmium (Cd) migration rules, translocation coefficients, rice biomass and yields. The results showed that, compared to CK, different fertilization methods of Si had significant impacts on decreasing Cd in brown rice and polished rice, but not in rice yields; In addition, Tsi + Ysi had the best effects to decrease Cd in edible grains, which resulted in Cd concentrations of husk, brown rice and polished rice reduced by 62.59%, 58.33% and 65.83%, respectively, and the effects of applying Tsi and Ysi were the second. Therefore, Tsi, Ysi and Tsi + Ysi were confirmed to be potential Cd pollution control technologies to rice.

  2. Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk

    Rudy Agustriyanto


    Full Text Available Coconut husk is classified as complex lignocellulosic material that contains cellulose, hemicellulose, lignin, and some other extractive compounds. Cellulose from coconut husk can be used as fermentation substrate after enzymatic hydrolysis. In contrary, lignin content from the coconut husk will act as an inhibitor in this hydrolysis process. Therefore, a pretreatment process is needed to enhance the hydrolysis of cellulose. The objective of this research is to investigate the production of the glucose through dilute acid pretreatment and to obtain its optimum operating conditions. In this study, the pretreatment was done using dilute sulfuric acid in an autoclave reactor. The pretreatment condition were varied at 80°C, 100°C, 120°C and 0.9%, 1.2%, 1.5% for temperature and acid concentration respectively. The acid pretreated coconut husk was then hydrolyzed using commercial cellulase (celluclast and β-glucosidase (Novozyme 188. The hydrolysis time was 72 hours and the operating conditions were varied at several temperature and pH. From the experimental results it can be concluded that the delignification temperature variation has greater influence than the acid concentration. The optimum operating condition was obtained at pH 4 and 50°C which was pretreated at 100°C using 1.5% acid concentration. Copyright © 2012 by BCREC UNDIP. All rights reserved. (Selected Paper from International Conference on Chemical and Material Engineering (ICCME 2012Received: 28th September 2012, Revised: 2nd October 2012, Accepted: 4th October 2012[How to Cite: R. Agustriyanto, A. Fatmawati, Y. Liasari. (2012. Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 137-141. doi:10.9767/bcrec.7.2.4046.137-141] [How to Link / DOI: ] | View in 

  3. Nanoemulsion drug delivery by ketene based polyester synthesized using electron rich carbon/silica composite surface.

    Swarnalatha, S; Selvi, P K; Ganesh Kumar, A; Sekaran, G


    A new carrier matrix for nanoemulsion drug delivery was synthesized from glycine as the raw material, using mesoporous/microporous electron rich carbon-silica composite surface (MAC(800)). MAC(800) was prepared from rice husk in two-stage carbonization. The surface area, pore volume, and pore size distribution of MAC(800) were measured, using nitrogen adsorption isotherms at 77K. The unpaired electron density of MAC(800) was measured in electron spin resonance spectroscopy (ESR), using TEMPOL (4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl) as the reference spin probe. Glycine was converted into ketene at the surface of MAC(800), which further underwent radical polymerization to form a low molecular weight ketene polymer (LMKP) of ester structure. The structure and the properties of LMKP were confirmed through (13)C, (1)H and DEPT nuclear magnetic resonance (NMR) spectroscopy, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and size exclusion chromatography (SEC). The two hydrophilic drugs namely ciprofloxacin hydrochloride (CPH) and gentamicin sulphate (GS) were chosen for the nanoemulsion preparation and characterization. They were characterized for morphology, interaction of drugs with the polymer and their crystallinity, using HR-TEM, DSC and XRD, respectively. The encapsulation efficiency of the LMKP towards the drugs ciprofloxacin hydrochloride and gentamicin sulphate were 26% and 12%, respectively. The dissolution studies of the nanoemulsion were carried out for the pH 6.5, 7.4 and 8.0. The cytocompatibility studies were done for LMKP as well as nanoemulsion using Hep2 epithelial cells.

  4. Properties of chars from the gasification and pyrolysis of rice waste streams towards their valorisation as adsorbent materials.

    Dias, D; Lapa, N; Bernardo, M; Godinho, D; Fonseca, I; Miranda, M; Pinto, F; Lemos, F


    Rice straw (RS), rice husk (RH) and polyethylene (PE) were blended and submitted to gasification and pyrolysis processes. The chars obtained were submitted to textural, chemical, and ecotoxic characterisations, towards their possible valorisation. Gasification chars were mainly composed of ashes (73.4-89.8wt%), while pyrolysis chars were mainly composed of carbon (53.0-57.6wt%). Silicon (Si) was the major mineral element in all chars followed by alkaline and alkaline-earth metal species (AAEMs). In the pyrolysis chars, titanium (Ti) was also a major element, as the feedstock blends contained high fractions of PE which was the main source of Ti. Gasification chars showed higher surface areas (26.9-62.9m(2)g(-1)) and some microporosity, attributed to porous silica. On the contrary, pyrolysis chars did not present a porous matrix, mainly due to their high volatile matter content. The gasification bed char produced with 100% RH, at 850°C, with O2 as gasification agent, was selected for further characterization. This char presented the higher potential to be valorised as adsorbent material (higher surface area, higher content of metal cations with exchangeable capacity, and lowest concentrations of toxic heavy metals). The char was submitted to an aqueous leaching test to assess the mobility of chemical species and the ecotoxic level for V. fischeri. It was observed that metallic elements were significantly retained in the char, which was attributed mainly to its alkaline character. This alkaline condition promoted some ecotoxicity level on the char eluate that was eliminated after the pH correction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Development and validation of an alternative to conventional pretreatment methods for residue analysis of butachlor in water, soil, and rice.

    Xue, Jiaying; Jiang, Wenqing; Liu, Fengmao; Zhao, Huiyu; Wang, Suli; Peng, Wei


    A rapid and effective alternative analytical method for residues of butachlor in water, soil, and rice was established. The operating variables affecting performance of this method, including different extraction conditions and cleanup adsorbents, were evaluated. The determination of butachlor residues in soil, straw, rice hull, and husked rice was performed using GC/MS after extraction with n-hexane and cleanup with graphite carbon black. The average recoveries ranged from 81.5 to 102.7%, with RSDs of 0.6-7.7% for all of the matrixes investigated. The limits of quantitation were 0.05 mg/kg in water and rice plant, and 0.01 mg/kg in soil, straw, rice hull, and husked rice. A comparison among this proposed method, the conventional liquid-liquid extraction, the Quick, Easy, Cheap, Effective, Rugged, and Safe method, and Soxhlet extraction indicated that this method was more suitable for analyzing butachlor in rice samples. The further validation of the proposed method was carried out by Soxhlet extraction for the determination of butachlor residues in the husked rice samples, and the residue results showed there was no obvious difference obtained from these two methods. Samples from a rice field were found to contain butachlor residues below the maximum residue limits set by China (0.5 mg/kg) and Japan (0.1 mg/kg). The proposed method has a strong potential for application in routine screening and processing of large numbers of samples. This study developed a more effective alternative to the conventional analytical methods for analyzing butachlor residues in various matrixes.

  6. Using rice straw to manufacture ceramic bricks

    Gorbunov German Ivanovich


    Full Text Available In the article, the co-authors offer their advanced and efficient methodologies for the recycling of the rice straw, as well as the novel approaches to the ceramic brick quality improvement through the application of the rice straw as the combustible additive and through the formation of amorphous silica in the course of the rice straw combustion. The co-authors provide characteristics of the raw materials, production techniques used to manufacture ceramic bricks, and their basic properties in the article. The co-authors describe the simulated process of formation of amorphous silica. The process in question has two independent steps (or options: 1 rice straw combustion and ash formation outside the oven (in the oxidizing medium, and further application of ash as the additive in the process of burning clay mixtures; 2 adding pre-treated rice straw as the combustible additive into the clay mixture, and its further burning in compliance with the pre-set temperature mode. The findings have proven that the most rational pre-requisite of the rice straw application in the manufacturing of ceramic bricks consists in feeding milled straw into the clay mixture to be followed by molding, drying and burning. Brick samples are highly porous, and they also demonstrate sufficient compressive strength. The co-authors have also identified optimal values of rice straw and ash content in the mixtures under research.




    This research aimed to determine chemical and physical component of rice husk ash as supplementing cement material to manufacture cement composite products. Charcoal of rice husk ash obtained by burning rice husk conventionally in kiln drum and burned again in furnace 1400 Barnsted Thermolyne Type at temperature 600o C for 2 hours. Analysis of chemical and physical component refer to SNI 15- 2049-2004. Major chemical compound of rice husk ash was 72.28 % of silica and 21.43 of LOI...

  8. Coffee husk waste for fermentation production of mosquitocidal bacteria.

    Poopathi, Subbiah; Abidha, S


    Coffee husk waste (CHW) discarded as bio-organic waste, from coffee industries, is rich in carbohydrates. The current study emphasizes the management of solid waste from agro-industrial residues for the production of biopesticides (Bacillus sphaericus, and B. thuringiensis subsp. israelensis), to control disease transmitting mosquito vectors. An experimental culture medium was prepared by extracting the filtrates from coffee husk. A conventional culture medium (NYSM) also was prepared. The studies revealed that the quantity of mosquitocidal toxins produced from CHW is at par with NYSM. The bacteria produced in these media, were bioassayed against mosquito vectors (Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti) and it was found that the toxic effect was statistically comparable. Cost-effective analysis have revealed that, production of biopesticides from CHW is highly economical. Therefore, the utilization of CHW provides dual benefits of effective utilization of environmental waste and efficient production of mosquitocidal toxins.


    Ş. İsmail KIRBAŞLAR


    Full Text Available In this study, moisture, ash, oil and cellulose of hazelnut husks, tea and tobacco wastes were analyzed. The amounts of pentosan, pentose and furfural were determined in the hazelnut husks, tea and tobacco wastes. Furfural was produced from each three waste products by a steam distillation method. IR spectra of each furfural product were measured and compared with standard furfural. Activated carbon prepared from the hazelnut husks at the different temperature, and organic and inorganic pollutants were removed by using the adsorbent obtained from hazelnut husk.


    Verónica Capdevila


    Full Text Available In this paper presents a simulation model of the fermentation/separation process of bioethanol from hydrolyzed pretreated rice husk, using Aspen HYSYS simulator. Sensitivity studies performed on the developed model indicated levels for selected variables: biomass/water ratio of 1:2,89 ; biomass flow of 50 t/h and inlet temperature separator of 30°C, leading to maximize the yield of bioethanol. From these variables, a bioethanol production of 8,81 t/h with a purity of 65,51% w/w is obtained, corresponding to a flow of hydrolyzed treated biomass of 50 t/h. This work represents an advance in the development of the simulation model of the complete process to obtain second generation of bioethanol from rice husks.

  11. Making sense of HUSK: practice implications for social change initiatives.

    McBeath, Bowen


    As an exemplar of bottom-up progressive social experimentation, HUSK provides opportunities to examine how innovative practice is supported and challenged in bureaucratic settings. In this analysis the author uses a sensemaking lens to identify critical issues and questions for those seeking to promote progressive change initiative in social welfare systems. Findings identify essential organizational and managerial supports needed to support service user voice and participation and reinforce the importance of reflexivity in practice and research.

  12. Efficacy of Locust Beans Husk Char in Heavy Metal Sequestration

    Ademola Ayodeji Ajayi-Banji; Temitayo Ewemoje; Adeniyi Ajimo


    Most solid waste management schemes minimally consider low concentration biodegradable agricultural waste management, though the environmental impact of this waste category is significant over a time frame. The column-mode study seeks to address the issue by suggesting potential utilisation of post-harvest waste for heavy metal sequestering. Locust beans husk char of 100 and 200 g was employed to inspect removal efficiency, isotherm and kinetic models of some heavy metals at 30, 60, 90, 120 a...

  13. Kinetics and isotherms of Neutral Red adsorption on peanut husk

    HAN Runping; HAN Pan; CAI Zhaohui; ZHAO Zhenhui; TANG Mingsheng


    Adsorption of Neutral Red (NR) onto peanut husk in aqueous solutions was investigated at 295 K. Experiments were carded out as function of pH, adsorbent dosage, contact time, and initial concentration. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Toth isotherm models. The results indicated that the Toth and Langmuir models provided the best correlation of the experimental data. The adsorption capacity of peanut husk for the removal of NR was determined with the Langmuir and found to be 37.5 mg/g at 295 K. The adsorption kinetic data were modeled using the pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic equations. It was seen that the pseudo-first order and pseudo-second order kinetic equations could describe the adsorption kinetics. The intraparticle diffusion model was also used to express the adsorption process at the two-step stage. It was implied that peanut husk may be suitable as adsorbent material for adsorption of NR from aqueous solutions.

  14. Sorption of Lead (II Ions on Activated Coconut Husk

    Amin Jahangard


    Full Text Available Background: In recent years, various toxic chemicals/compounds have been widely detected at dangerous levels in drinking water in many parts of the world posing a variety of serious health risks to human beings. One of these toxic chemicals is lead, so this paper aimed to evaluate of efficiency coconut husk as cheap adsorbent for removal lead under different conditions. Methods: In the spring of 2015, batch studies were performed in laboratory (Branch of Hamadan, Islamic Azad University, to evaluate the influences of various experimental parameters like pH, initial concentration, adsorbent dosage, contact time and the effect of temperature on the adsorption capacity of coconut husk for removal lead from aqueous solution. Results: Optimum conditions for Pb (II removal were pH 6, adsorbent dosage 1g/100ml of solution and equilibrium time 120 min. The adsorption isotherm was also affected by temperature since the adsorption capacity was increased by raising the temperature from 25 to 45 °C. The equilibrium adsorption isotherm was better described by Freuindlich adsorption isotherm model. Conclusion: It is evident from the literature survey that coconut-based biosorbents have shown good potential for the removal of various aquatic pollutants. Coconut husk-based activated carbon can be a promising adsorbent for removal of Pb from aqueous solutions.

  15. 76 FR 78231 - Notice of Decision To Authorize the Importation of Fresh Cape Gooseberry Fruit With Husks From Chile


    ... continental United States of fresh Cape gooseberry fruit (Physalis peruviana L.) with husks from Chile. Based... fresh Cape gooseberry fruit (Physalis peruviana L.) with husks from Chile. We solicited comments on...

  16. Uptake of Arsenic in Rice Plant Varieties Cultivated with Arsenic Rich Groundwater

    Piyal Bhattacharya


    Full Text Available Groundwater of many areas of West Bengal, India is severely contaminated with arsenic. The paddy soil gets con¬taminated from the groundwater and thus there is a probability of bioaccumulation of arsenic in rice plants cultivated with arsenic contaminated groundwater and soil. This study aims at assessing the level of arsenic in irrigation water and soil and to investigate the seasonal bioaccumulation of arsenic in the various parts (straw, husk and grain of the rice plant of differ¬ent varieties in the arsenic affected two blocks (Chakdaha and Ranaghat-I of Nadia district, West Bengal. It was found that the arsenic uptake in rice during the pre-monsoon season is more than that of the post-monsoon season. The accumulation of arsenic found to vary with different rice varieties; the maximum accumulation was in White minikit (0.31±0.005 mg/kg and IR 50 (0.29±0.001 mg/kg rice varieties and minimum was found to be in the Jaya rice variety (0.14±0.002 mg/kg. In rice plant maximum arsenic accumulation occurred in the straw part (0.89±0.019-1.65±0.021 mg/kg compared to the ac¬cumulation in husk (0.31±0.011-0.85±0.016 mg/kg and grain (0.14±0.002-0.31±0.005 mg/kg parts. For any rice sample concentration of arsenic in the grain did not exceed the WHO recommended permissible limit in rice (1.0 mg/kg.

  17. Nutritive Value of Coffee Husk Fermented with Pleurotus ostreatus as Ruminant Feed

    I. Badarina


    Full Text Available Coffee husks is an abundant crop residue but the content of anti nutritional substances such as caffeine, tannin, and lignin limit its utilization as feed ingredients. Higher fungi such as Pleurotus ostreatus have the ability to biotransform lignocellulosic materials through their extracellular enzyme activities. This study was carried out to assess the effect of solid state fermentation by using P. ostreatus on nutrient composition of coffee husk and to evaluate its potency as ruminant feed in vitro. The in vitro experiment was conducted to determine fermentability of treated coffee husk. The usage rate of fermented coffee husk was mimicked feeding level to mid lactation dairy cows; 0%, 10%, 20%, 30%, and 40% (R0 to R4. Fermentation of coffee husk by P. ostreatus increased its protein, from 10.36% to 12.14%, and cellulose, from 19.51% to 24.80%, and decreased its lignin, from 65.42% to 45.04%, tannin from 1.02% to 0.18%, and caffeine, from 1.39% to 0.20%, concentrations. There were no differences in ruminal pH and N-ammonia production but volatile fatty acid production and dry matter digestibility decreased as the fermented coffee husk level increased. The ruminal protozoa population in fermented coffee husk diets was lower than the control diets (P<0.05. In conclusion, it is possible to use 20% of fermented coffee husk in the ration.

  18. Frictional and heat resistance characteristics of coconut husk particle filled automotive brake pad

    Bahari, Shahril Anuar; Chik, Mohd Syahrizul; Kassim, Masitah Abu; Som Said, Che Mohamad; Misnon, Mohd Iqbal; Mohamed, Zulkifli; Othman, Eliasidi Abu


    The objective of this study was to determine the friction and heat resistance characteristics of automotive brake pad composed with different sizes and percentages of coconut husk particle. The materials used were phenolic resin (phenol formaldehyde) as binder, copper, graphite and brass as friction producer/modifiers, magnesium oxide as abrasive material, steel and barium sulfate as reinforcement while coconut husk particle as filler. To obtain particle, the coconut husk was ground and dried to 3% moisture content. Then the coconut husk particle was screened using 80 mesh (to obtain coarse dust) and 100 mesh (to obtain fine dust). Different percentages of particle, such as 10 and 30% were used in the mixture of brake pad materials. Then the mixture was hot-pressed to produce brake pad. Chase machine was used to determine the friction coefficient in friction resistance testing, while thermogravimetric analyzer (TGA) machine was used to determine the heat decomposition values in heat resistance testing. Results showed that brake pad with 100 mesh and 10% composition of coconut husk particle showed the highest friction coefficient. For heat resistance, brake pad with 100 mesh and 30% composition of coconut husk dust showed the highest decomposition temperature, due to the high percentage of coconut husk particle in the composition, thus increased the thermal stability. As a comparison, brake pad composed with coconut husk particle showed better heat resistance results than commercial brake pad.

  19. Implications of silica on biorefineries – interactions with organic material and mineral elements in grasses

    Le, Duy Michael; Sørensen, Hanne Risbjerg; Knudsen, Niels Ole


    Biorefineries aim to convert low value biomasses into high value products. The feedstock biomasses are often high-silica agricultural waste products such as rice straw, wheat straw, corn stover, sugarcane bagasse, or empty fruit bunches. This causes challenges, since silica is problematic...

  20. Anti-inflammatory effects of Zea mays L. husk extracts.

    Roh, Kyung-Baeg; Kim, Hyoyoung; Shin, Seungwoo; Kim, Young-Soo; Lee, Jung-A; Kim, Mi Ok; Jung, Eunsun; Lee, Jongsung; Park, Deokhoon


    Zea mays L. (Z. mays) has been used for human consumption in the various forms of meal, cooking oil, thickener in sauces and puddings, sweetener in processed food and beverage products, bio-disel. However, especially, in case of husk extract of Z. mays, little is known about its anti-inflammatory effects. Therefore, in this study, the anti-inflammatory effects of Z. mays husk extract (ZMHE) and its mechanisms of action were investigated. The husks of Z. Mays were harvested in kangwondo, Korea. To assess the anti-inflammatory activities of ZMHE, we examined effects of ZMHE on nitric oxide (NO) production, and release of soluble intercellular adhesion molecule-1 (sICAM-1) and eotaxin-1. The expression level of inducible nitric oxide synthase (iNOS) gene was also determined by Western blot and luciferase reporter assays. To determine its mechanisms of action, a luciferase reporter assay for nuclear factor kappa B (NF-kB) and activator protein-1 (AP-1) was introduced. ZMHE inhibited lipopolysaccharide (LPS)-induced production of NO in RAW264.7 cells. In addition, expression of iNOS gene was reduced, as confirmed by Western blot and luciferase reporter assays. Effects of ZMHE on the AP-1 and NF-kB promoters were examined to elucidate the mechanism of its anti-inflammatory activity. Activation of AP-1 and NF-kB promoters induced by LPS was significantly reduced by ZMHE treatment. In addition, LPS-induced production of sICAM-1 and IL-4-induced production of eotaxin-1 were all reduced by ZMHE. Our results indicate that ZMHE has anti-inflammatory effects by downregulating the expression of iNOS gene and its downregulation is mediated by inhibiting NF-kB and AP-1 signaling.


    Didi Dwi Anggoro


    Full Text Available Rice husk is the milling byproduct of rice and is a major waste product of the agriculture industry. Amorphous silica, commonly referred to as rice husk ash, was extracted from rice husk by acid leaching, pyrolysis, and carbon-removing processes. These properties make the ash a valuable raw material for many industries.  This paper is study of synthesized of zeolite Y from rice husk ash. Zeolite Y synthesis is used for petroleum industry as expensive catalyst. Rice husk was calcined at temperature 700oC for two hours using furnace to produce pure silica. The composition of synthesized of zeolite Y from rice husk was 2.24 Na2O:Al2O3:8SiO2:112 H2O. The gel solution was mixed at room temperature for 24 hours using autoclave. Then, the gel solution was heated with variable temperature and time crystallization. The product zeolite synthesis Y was filtered and washed with distilled water until pH lower than ten, than dried at oven. This product was analyzed with X-Ray Diffraction (XRD. From XRD analyze result indicated that from rice husk ash can produced zeolite synthesis Y which high crystallization degree. The optimum conditions for synthesis of zeolite Y from rice husk ash are temperature at 100oC for 48 hours, silicate at 20%, and aluminate at 10%.

  2. Possible use of psyllium husk as a release retardant

    Desai Angira


    Full Text Available Various hydrophilic polymers from synthetic origin such as methylcellulose, PEGs, HPMC as well as those from natural world such as guar gum, tragacanth, xanthan gum have been used to formulate oral sustained release formulations. Psyllium husk has the ability to swell 10-14 times of its original volume and form a hydrogel. It is biocompatible, inexpensive, inert, non-absorbable, environment friendly and easily available. However, its use as a release retardant has not been fully explored. Owing to large dose, high sensitivity to light, moisture and heat and also very short half-life of 1-2 h; formulation of sustained release dosage form of amoxicillin trihydrate is a challenge. Hence the present study has been undertaken to develop sustained release granules as well as matrix tablets of amoxicillin trihydrate using psyllium husk as a primary release retardant. The drug release of these formulations was compared with those containing HPMC K4M.The results showed insignificant difference in t80% value for drug release as assessed by student′s t-test at 5% level of significance. Selected formulations were kept at controlled conditions of 40o/75% RH and 30o/65% RH for a period of 3 mo. Microbiological assay was used as a stability indicating method of assay. Sustained release granules and tablet formulations containing HPMC alone were found to be more stable than the similar formulations containing husk with percent drug content at the end of 3 mo at 40o/ 75% RH being 92.66%, 93.81%, 86.74%, 88.31% and the rate of degradation being 8.46x10-4 d-1, 7.1x10-4 d-1, 1.58x10-3 d-1 and 1.38x10-3 d-1, respectively. Thus it was concluded that psyllium husk can be effectively used as a hydrogel polymer in sustained release formulations. However, there is a need to keep moisture level under control during and after formulation.

  3. Antimicrobial Activity of UV-Induced Phenylamides from Rice Leaves

    Hye Lin Park


    Full Text Available Rice produces a wide array of phytoalexins in response to pathogen attacks and UV-irradiation. Except for the flavonoid sakuranetin, most phytoalexins identified in rice are diterpenoid compounds. Analysis of phenolic-enriched fractions from UV-treated rice leaves showed that several phenolic compounds in addition to sakuranetin accumulated remarkably in rice leaves. We isolated two compounds from UV-treated rice leaves using silica gel column chromatography and preparative HPLC. The isolated phenolic compounds were identified as phenylamide compounds: N-trans-cinnamoyltryptamine and N-p-coumaroylserotonin. Expression analysis of biosynthetic genes demonstrated that genes for arylamine biosynthesis were upregulated by UV irradiation. This result suggested that phenylamide biosynthetic pathways are activated in rice leaves by UV treatment. To unravel the role of UV-induced phenylamides as phytoalexins, we examined their antimicrobial activity against rice fungal and bacterial pathogens. N-trans-Cinnamoyltryptamine inhibited the growth of rice brown spot fungus (Bipolaris oryzae. In addition to the known antifungal activity to the blast fungus, sakuranetin had antimicrobial activity toward B. oryzae and Rhizoctonia solani (rice sheath blight fungus. UV-induced phenylamides and sakuranetin also had antimicrobial activity against rice bacterial pathogens for grain rot (Burkholderia glumae, blight (Xanthomonas oryzae pv. oryzae and leaf streak (X. oryzae pv. oryzicola diseases. These findings suggested that the UV-induced phenylamides in rice are phytoalexins against a diverse array of pathogens.

  4. Reduction of Cadmium Uptake of Rice Plants Using Soil Amendments in High Cadmium Contaminated Soil: A Pot Experiment

    Dian Siswanto


    Full Text Available The aims of this study were to investigate the effect of agricultural residues on reducing cadmium uptake in rice plants. The rice plants growing on no cadmium/free cadmium soils (N, Cd soils (Cds, and Cd soils each amended with 1% w/w of coir pith (CP, coir pith modified with sodium hydroxide (CPm and corncob (CC under high cadmium contaminated soil with an average 145 mg Cd kg-1 soil were investigated. The results showed that the cumulative transpiration of rice grown in various treatments under high cadmium contaminated soil followed the order: Cds > CPm ≥ CP ≥ CC. These transpirations directly influenced cadmium accumulation in shoots and husks of rice plants. The CC and CP seemed to work to reduce the cadmium uptake by rice plants indicated by accumulated cadmium in the husk that were 2.47 and 7.38 mg Cd kg-1 dry weight, respectively. Overall, transpiration tended to drive cadmium accumulation in plants for rice grown in high cadmium contaminated soil. The more that plants uptake cadmium, the lower cadmium that remains in the soil.

  5. Grain yield and arsenic uptake of upland rice inoculated with arbuscular mycorrhizal fungi in As-spiked soils.

    Wu, Fuyong; Hu, Junli; Wu, Shengchun; Wong, Ming Hung


    A pot trial was conducted to investigate the effects of three arbuscular mycorrhizal (AM) fungi species, including Glomus geosporum BGC HUN02C, G. versiforme BGC GD01B, and G. mosseae BGC GD01A, on grain yield and arsenic (As) uptake of upland rice (Zhonghan 221) in As-spiked soils. Moderate levels of AM colonization (24.1-63.1 %) were recorded in the roots of upland rice, and up to 70 mg kg(-1) As in soils did not seem to inhibit mycorrhizal colonization. Positive mycorrhizal growth effects in grain, husk, straw, and root of the upland rice, especially under high level (70 mg kg(-1)) of As in soils, were apparent. Although the effects varied among species of AM fungi, inoculation of AM fungi apparently enhanced grain yield of upland rice without increasing grain As concentrations in As-spiked soils, indicating that AM fungi could alleviate adverse effects on the upland rice caused by As in soils. The present results also show that mycorrhizal inoculation significantly (p < 0.05) decreased As concentrations in husk, straw, and root in soils added with 70 mg kg(-1) As. The present results suggest that AM fungi are able to mitigate the adverse effects with enhancing rice production when growing in As-contaminated soils.

  6. Preparation of food grade carboxymethyl cellulose from corn husk agrowaste.

    Mondal, Md Ibrahim H; Yeasmin, Mst Sarmina; Rahman, Md Saifur


    Alpha-cellulose extracted from corn husks was used as the raw material for the production of food-grade carboxymethyl cellulose (CMC). Preparation of CMC from husk cellulose was carried out by an etherification process, using sodium hydroxide and monochloroacetic acid (MCA), with ethanol as the supporting medium. Characterizations of CMC were carried out by analyzing the spectra of FTIR, XRD patterns and SEM photomicrographs. Degree of substitution (DS) was determined with respect to particle size using chemical methods. Solubility, molecular weight and DS of CMC increased with decreased cellulose particle sizes. Microbiological testing of the prepared CMC was done by the pour plate method. Concentrations of heavy metals such as arsenic, lead, cadmium and mercury in the purified CMC were measured by Atomic Absorption Spectroscopy technique and found to be within the WHO/FAO recommended value. A comparative study with CMC available in the international market was conducted. The purity of the prepared CMC was higher, at 99.99% well above the purity of 99.5% for standard CMC. High purity CMC showed a yield 2.4 g/g with DS 2.41, water holding capacity 5.11 g/g, oil holding capacity 1.59 g/g. The obtained product is well suited for pharmaceutical and food additives.


    Khusid S. B.


    Full Text Available The article describes the results of the complex feed additive based on sunflower husk, enriched with beer wort with the addition of pumpkin pulp. We have studied the chemical composition of sunflower husk, which is the secondary resource of the processing plant raw material, selected methods of enrichment of this raw material with the help of fungi Trichoderma harzianum. Cellulolytic enzyme preparations on the basis of fungi of the genus Trichoderma for use in agriculture and animal feed production is often obtained when the surface method of cultivation. These drugs are cheap and contain a significant number of related hydrolytic enzymes, 29 such as amylase, protease, pectinase and hemicellulase, which are also important and valuable to the consumer. As a vitamin component of the feed additive we have selected a pumpkin pulp, which is a valuable feed for livestock and poultry is a source of carotene, fat and nitrogenous substances. We have also developed elements of technology for complex feed additive. We have created a comprehensive feed additive which can be used in the composition of diets in the feeding of farm animals and poultry

  8. Efficacy of Locust Beans Husk Char in Heavy Metal Sequestration

    Ademola Ayodeji Ajayi-Banji


    Full Text Available Most solid waste management schemes minimally consider low concentration biodegradable agricultural waste management, though the environmental impact of this waste category is significant over a time frame. The column-mode study seeks to address the issue by suggesting potential utilisation of post-harvest waste for heavy metal sequestering. Locust beans husk char of 100 and 200 g was employed to inspect removal efficiency, isotherm and kinetic models of some heavy metals at 30, 60, 90, 120 and 150 min contact time. Elemental composition of the biosorbent was investigated using the SEM-EDX machine. The results obtained depict that over 85% aluminium and nickel removal was achieved at 150 min detention time. The Freundlich isotherm well described most of the sorbates sorption (R2 ≥ 0.91. The sorption rate equally fitted into the second-order pseudo kinetic model (R2 ≥ 0.88. Ion exchange took place during the sorption. Locust beans husk has promising adsorption potential in heavy metal ions removal from fouled surface water. DOI:

  9. Effects Of Storage Conditions On The Quality Of Unripe Hazelnuts In The Husk

    Markuszewski Bogumił


    Full Text Available The purpose of the study was to assess the storability of unripe hazelnuts in the husk of four cultivars: ‘Hall’s Giant’, ‘Catalan’, ‘Webb’s Prize Cob’ and ‘Cosford’. The nuts were stored in normal and controlled atmospheres, and in Xtend® bags for three months. A quality assessment was performed based on the following parameters: weight of the nut in the husk and without the husk, weight of the kernel, percentage of nuts with husk attached, dry matter content in kernels, infection with fungal diseases, and the presence of physiological disorders. The study demonstrated that hazelnuts stored in Xtend® bags and under a controlled atmosphere had a higher weight for the nut in the husk and without the husk, as well as a higher weight of the kernel and water content when compared to batches of hazelnuts stored in a normal atmosphere. The percentage of nuts remaining in the husk was also higher when stored under such conditions. For the majority of investigated cultivars the storage in Xtend® bags, and to a lesser extent under normal atmosphere conditions, resulted in a substantial increase in nuts infected with fungal and abiotic diseases. Among investigated cultivars, ‘Hall’s Giant’ turned out to be the most resistant to storage diseases.

  10. Increased water resistance of CTMP fibers by oat (Avena sativa L.) husk lignin.

    Sipponen, Mika H; Pastinen, Ossi A; Strengell, Reetta; Hyötyläinen, Juha M I; Heiskanen, Isto T; Laakso, Simo


    The insertion of oat husk lignin onto chemithermomechanical pulp (CTMP) fibers was studied to increase fiber hydrophobicity. The pretreated pulp samples were subsequently used for preparation of handsheets for characterization. Treatment of CTMP with laccase in the presence of oat husk lignin resulted in a significant increase in hydrophobicity of the handsheet surface, as indicated by dynamic contact angle analysis. Water absorption time of 8 s was obtained with initial contact angle of 118°. Although the handsheet's brightness was reduced by 33%, tensile index was only subtly decreased. Neither laccase nor oat husk lignin alone gave much improved water absorption times. Therefore, handsheets made of laccase-treated pulp with and without oat husk lignin were further examined by XPS, which suggested that both laccase and oat husk lignin were inserted onto CTMP fibers. The oat husk lignin was distributed as heterogeneous aggregates on the handsheet surface whereas laccase was uniformly distributed. Evidence was obtained that the adsorbed laccase layer formed a noncovalent base for the insertion of oat husk lignin onto fiber surfaces.

  11. Production of Flammulina velutipes on coffee husk and coffee spent-ground

    Leifa Fan


    Full Text Available Solid state cultivation (SSC was carried out to evaluate the feasibility of using coffee husk and spent-ground as substrates for the production of edible mushroom Flammulina under different conditions of moisture and spawn rate. The strain of F. velutipes LPB 01 was adapted for a coffee husk extract medium. Best results were obtained with 25% spawn rate, though there was not much difference when lower spawn rates (10-20% were used. Ideal moisture content for mycelial growth was 60% and 55% for coffee husk and spent-ground, respectively. With coffee husk as substrate, first fructification occurred after 25 days of inoculation and the biological efficiency reached about 56% with two flushes after 40 days. With spent-ground as substrate, first fructification occurred 21 days after inoculation and the biological efficiency reached about 78% in 40 days. There was decrease in the caffeine and tannins contents (10.2 and 20.4%, respectively in coffee husk after 40 days. In coffee spent-ground, the tannin contents decreased by 28% after 40 days. These decrease was attributed to the degradation of caffeine or tannins by the culture because these were not adsorbed in the fungal mycelia. Results showed the feasibility of using coffee husk and coffee spent-ground as substrate without any nutritional supplementation for cultivation of edible fungus in SSC. Spent ground appeared better than coffee husk.

  12. Digestibility, Milk Production, and Udder Health of Etawah Goats Fed with Fermented Coffee Husk

    I. Badarina


    Full Text Available This study was carried out to assess the utilization of coffee husk fermented by Pleurotus ostreatus as feed supplement by measuring the digestibility, milk production and udder health of Etawah goats suffered from subclinical mastitis (+1. There were three experimental diets consisted of T0 (control diet/basal diet without fermented coffee husk, T1 (basal diet with 6% fermented coffee husk and T2 (basal diet with 6% fermented coffee husk soaked in crude palm oil for an hour before using. Basal diet consisted of napier grass (60% and concentrate (40%. The results showed that supplementation of lactating Etawah does with fermented coffee husk did not affect the palatability of the diets, but increased the protein and crude fiber consumption (P<0.05. There was no significant effect on nutrient digestibility and milk production while milk composition (protein, fat, total solid increased in supplemented groups (P<0.05. The persistency of milk production and the somatic cells count were not different. There was an improvement of somatic cells count on supplemented groups. In conclusion, fermented coffee husk could be used as feed supplement without any negative effects on digestibility and milk production. The positive effects to udder health could be expected from including fermented coffee husk in diets.

  13. Solid State production of manganese peroxidases using arecanut husk as substrate

    Akhila Rajan


    Full Text Available The lignocellulosic biomass from arecanut husk (Areca catechu Linnaeus was evaluated as a new substrate for cultivation of Phanerochaete chrysosporium and Phanerochaete sp for solid state fermentation of manganese peroxidase (MnP. Arecanut had a moisture content of 79.84 % for ripe nut husk whereas green nut husk had 68.39 % moisture and a pH of 5.0, 3.0 and 7.0 for raw, ripe and dry husk. Reducing sugar content was 14.31, 19.21 and 1.77(mg/g of husk for raw, ripe and dry nut husk, respectively. Non reducing sugar was 1.04(mg/g of husk for raw and 0.68 (mg/g of husk for dry husk. Solid state fermentation carried out at different pH showed optimum enzyme production at pH 6.0 (52.60 IU/g for P.chrysosporium and pH 5.0 (44.08 IU/g for Phanerochaete sp. Optimum temperature was 30 ± 2º C for both the organisms. Lower concentration of MnSO4 (0.1 mM MnSO4 induced maximum enzyme production in P.chrysosporium whereas Phanerochaete sp. required 1 mM MnSO4 for induction. Absence of carbon and nitrogen stimulated enzyme production in P.chrysosporium while Phanerochaete sp. needed nitrogen. Enzyme was partially purified by ammonium sulphate precipitation followed by ion exchange chromatography.

  14. Comet assay to assess the genotoxicity of Persian walnut (Juglans regia L.) husks with statistical evaluation.

    Petriccione, Milena; Ciniglia, Claudia


    The aim of this study was to confirm the utility of the Comet assay as a genotoxicity screening test for evaluating the impact of walnut husk aqueous extract. Phytotoxicity assays using diluted and undiluted walnut husk aqueous extracts were performed on young roots of Raphanus sativus (radish), and the Comet assay was used to evaluate DNA integrity in isolated radish radicle nuclei. The results reveal a dose-dependent accumulation of DNA damage in radish radicles treated with walnut husks water extract and that the Kolmogorov-Smirnov test combined with Johnson SB distribution was the best approach for describing Comet assay data.

  15. Utilisation of rice residues for decentralised electricity generation in Ghana

    Ramamurthi, Pooja Vijay; Fernandes, Maria Cristina; Nielsen, Per Sieverts


    Developing countries, especially in Sub-Saharan Africa, face large challenges to achieve universal electrification. Using the case of Ghana, this study explores the role that rice residues can play to help developing countries meet their electrification needs. In Ghana, Levelised Electricity Costs...... (LEC) of a grid-connected 5 MWe straw combustion plant ranged between 11.6 and 13.0 UScents/kWh, based on region of implementation. Rice straw combustion is a viable grid-connected option in all regions, as the bioenergy Feed-in-Tariff is 29.5 UScents/kWh in Ghana. Residue supply cost contributes...... the average LEC of grid extension diesel mini-grids and off-grid solar systems for remote communities in Ghana. Electricity produced from husk gasification has the potential to cater to 7% of the needs of un-electrified communities in Ghana. The methodology and analysis of this study can support policymakers...

  16. Accumulation of mercury and cadmium in rice from paddy soil near a mercury mine.

    Li, W C; Ouyang, Y; Ye, Z H


    Paddy soil and rice (Oryza sativa L.) in the Wanshan mining area in Guizhou Province, China, have been contaminated by toxic trace metals such as cadmium (Cd) and mercury (Hg). The present study examined correlations between the types and physicochemical parameters of the soil and the contents of trace metals and the different forms of Hg in rice. The health risks of consuming contaminated rice from the Wanshan mining area were also assessed. Sequential extraction procedures were used to investigate the chemical behavior of Hg in the soil. The results showed that Hg and Cd were the most abundant trace metals in the Wanshan mining area. The toxic methylmercury (MeHg) content was substantial in brown rice, and the total amounts of total Hg (THg), diethylenetriaminepentaacetic acid-Hg, and water-soluble Hg varied in the rhizosphere and non-rhizosphere soils. An antagonistic interaction between Mn in brown rice, straw, and husk and MeHg in brown rice was also shown. An analysis of calculated dietary intake, target hazard quotients, and hazard indexes showed a potential risk of transferring Hg, MeHg, and Cd to humans when rice from the Wanshan mining area is consumed. Therefore, it must be concluded that consuming contaminated rice near the Wanshan mining area is a potential threat to human health.

  17. Utilization of crops residues as compost and biochar for improving soil physical properties and upland rice productivity

    J. Barus


    Full Text Available The abundance of crops waste in the agricultural field can be converted to organic fertilizer throughout the process of composting or pyrolysis to return back into the soil. The study aimed to elucidate the effect of compost and biochar application on the physical properties and productivity of upland rice at Village of Sukaraja Nuban, Batanghari Nuban Sub district, East Lampung Regency in 2015. The amendment treatments were A. control; B. 10 t rice husk biochar/ ha; C. 10 t maize cob biochar/ha; D. 10 t straw compost/ha; E. 10 t stover compost/ha, F. 10 t rice husk biochar/ha + 10 t straw compost/ha; F. 10 t maize cob biochar/ha + 10 t maize stover compost/ha. The treatments were arranged in randomized block design with four replicates. The plot size for each treatment was 10 x 20 m. After incubation for about one month, undisturbed soil samples were taken using copper ring at 10–20 cm depth for laboratory analyzes. Analyses of soil physical properties included bulk density, particle density, total porosity, drainage porosity, and soil water condition. Plant observations conducted at harvest were plant height, number of panicle, number of grain/panicle, and grain weight/plot. Results of the study showed that biochar and compost improved soil physical properties such as bulk density, total porosity, fast drainage pores, water content, and permeability of soil. The combination of rice husk biochar and straw compost gave better effect than single applications on rice production components (numbers of panicle and grains of rice, and gave the highest yield of 4.875 t/ha.

  18. Logistics cost analysis of rice residues for second generation bioenergy production in Ghana.

    Vijay Ramamurthi, Pooja; Cristina Fernandes, Maria; Sieverts Nielsen, Per; Pedro Nunes, Clemente


    This study explores the techno-economic potential of rice residues as a bioenergy resource to meet Ghana's energy demands. Major rice growing regions of Ghana have 70-90% of residues available for bioenergy production. To ensure cost-effective biomass logistics, a thorough cost analysis was made for two bioenergy routes. Logistics costs for a 5 MWe straw combustion plant were 39.01, 47.52 and 47.89 USD/t for Northern, Ashanti and Volta regions respectively. Logistics cost for a 0.25 MWe husk gasification plant (with roundtrip distance 10 km) was 2.64 USD/t in all regions. Capital cost (66-72%) contributes significantly to total logistics costs of straw, however for husk logistics, staff (40%) and operation and maintenance costs (46%) dominate. Baling is the major processing logistic cost for straw, contributing to 46-48% of total costs. Scale of straw unit does not have a large impact on logistic costs. Transport distance of husks has considerable impact on logistic costs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Ageing of rice husk biochar along a freeze-thaw cycles

    Miao Wei; Cheng Xiao Ying; Meng Jun; Tang Liang


    In order to elucidate the aging possess of biochar, the experiment with treatment biochar with soil were performed. For accelerating aging process, freeing-thawing cycle were conducted to simulate the changing process of the physical and chemical properties of biochar and explore the roles of biochar in the changes of the soil nutrition. Aging treatment has a significant impact on the physical and chemical properties of biochar. The pH values, element composition, oxidation of the surface, ab...

  20. From rice husk to high performance shape stabilized phase change materials for thermal energy storage

    Mehrali, Mohammad; Latibari, Sara Tahan; Rosen, Marc A.


    exceptional phase change behavior, having a desirable latent heat storage capacity of 175 kJ kg(-1). When exposed to high solar radiation intensities, the composites can absorb and store the thermal energy. An FTIR analysis of the SSPCMs indicated that there was no chemical interaction between the palmitic...... and excellent reversibility. The prepared SSPCMs with enhanced heat transfer and phase change properties provide a beneficial option for building energy conservation and solar energy applications owing to the low cost of raw materials and the simple synthetic technique....

  1. Effects of Rice Husk Ash on Some Geotechnical Properties of Lateritic Soil

    Fidelis O. OKAFOR


    Full Text Available The study is an investigation into the effect of RHA on some geotechnical properties of a lateritic soil classified as A-2-6 (0 or SW for sub-grade purposes. The investigation includes evaluation of properties such as compaction, consistency limits and strength of the soil with RHA content of 5%, 7.5%, 10% and 12.5% by weight of the dry soil. The results obtained show that the increase in RHA content increased the OMC but decreased the MDD. It was also discovered that increase in RHA content, reduced plasticity and increased volume stability as well as the strength of the soil. 10% RHA content was also observed to be the optimum content.

  2. Cellulose nanowhiskers from coconut husk fibers: effect of preparation conditions on their thermal and morphological behavior

    Cellulose nanowhiskers were prepared by sulfuric acid hydrolysis from coconut husk fibers which had previously been submitted to a delignification process. The effects of preparation conditions on the thermal and morphological behavior of the nanocrystals were investigated. Cellulose nanowhisker sus...

  3. Juglone Content in Leaf and Green Husk of Five Walnut (Juglans regia L. Cultivars

    Sina Niculina COSMULESCU


    Full Text Available Juglone (5-hydroxy-1,4-napthoquinone is a chemical compound released by walnut trees that can be toxic for surrounding plant species. In the present study, juglone was identified in leaves and green husk in five walnut cultivars: Germisara, Jupanesti, Franquette, Vina, Valcor by using high performance liquid chromatography (HPLC-RP. Juglone was found predominant in green husk (average value of cultivars is about 31.308 mg/100 g. Significant differences in contents of identified juglone were observed among cultivars that ranged from 20.56 to 42.78 mg/100g for green husk, and 5.42 to 22.82 mg/100 g for leaves. It was also found that walnut green husk and leaves represent the most important source of walnut phenolics.

  4. Use of psyllium (isubgol) husk as an alternative gelling agent for the ...



    Apr 17, 2008 ... microalgae (Cyanobacteria) Chroococcus limneticus and eukaryotic green ... psyllium husk were far lower than 722000 cells mL-1 on agar gelled ..... Evidence for the recognition of a secondary structure of carrageenan.

  5. Nutritive Value of Coffee Husk Fermented with Pleurotus ostreatus as Ruminant Feed

    I. Badarina; D. Evvyernie; T. Toharmat; E. N. Herliyana; L. K. Darusman


    Coffee husks is an abundant crop residue but the content of anti nutritional substances such as caffeine, tannin, and lignin limit its utilization as feed ingredients. Higher fungi such as Pleurotus ostreatus have the ability to biotransform lignocellulosic materials through their extracellular enzyme activities. This study was carried out to assess the effect of solid state fermentation by using P. ostreatus on nutrient composition of coffee husk and to evaluate its potency as ruminant feed ...

  6. Grain Unloading of Arsenic Species in Rice

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Charnock, John M.; Feldmann, Joerg; Price, Adam H.; Meharg, Andrew A. (EPA); (U. South Australia); (Manchester); (Aberdeen); (UC)


    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a {+-} stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols.

  7. Physical, chemical and mechanical properties of pehuen cellulosic husk and its pehuen-starch based composites.

    Castaño, J; Rodríguez-Llamazares, S; Carrasco, C; Bouza, R


    Pehuen cellulosic husk was characterized and employed as reinforcement for composite materials. In this research, thermoplastic pehuen starch (TPS) and TPS/poly(lactic acid) (PLA)/polyvinyl alcohol (PVA) composites, reinforced with 5 and 10% of pehuen husk, were prepared by melt-blending. Comparative samples of pehuen TPS and TPS/PLA/PVA blend were also studied. Physical, thermal, structural and mechanical properties of composites were evaluated. Pehuen husk mainly consists of cellulose (50 wt%), hemicellulose (30 wt%) and lignin (14 wt%). In respect to lipids, this husk has only a 0.6 wt%. Its surface is smooth and damage-free and it is decomposed above 325 °C. The incorporation of pehuen husk improved considerably the thermal stability and mechanical properties of the studied composites, mainly in TPS composites. Their thermal stability enhances since biofiber hinders the "out-diffusion" of volatile molecules from the polymer matrix, while mechanical properties could raise due to the natural affinity between husk and starch in the pehuen seed.

  8. Biosorption of Am-241 and Cs-137 by radioactive liquid waste by coffee husk

    Ferreira, Rafael Vicente de Padua; Sakata, Solange Kazumi; Bellini, Maria Helena; Marumo, Julio Takehiro, E-mail: jtmarumo@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)


    Radioactive Waste Management Laboratory of Nuclear and Energy Research Institute, IPEN-CNEN/SP, has stored many types of radioactive liquid wastes, including liquid scintillators, mixed wastes from chemical analysis and spent decontamination solutions. These wastes need special attention, because the available treatment processes are often expensive and difficult to manage. Biosorption using biomass of vegetable using agricultural waste has become a very attractive technique because it involves the removal of heavy metals ions by low cost biossorbents. The aim of this study is to evaluate the potential of the coffee husk to remove Am-241 and Cs-137 from radioactive liquid waste. The coffee husk was tested in two forms, treated and untreated. The chemical treatment of the coffee husk was performed with HNO{sub 3} and NaOH diluted solutions. The results showed that the coffee husk did not showed significant differences in behavior and capacity for biosorption for Am-241 and Cs-137 over time. Coffee husk showed low biosorption capacity for Cs-137, removing only 7.2 {+-} 1.0% in 4 hours of contact time. For Am-241, the maximum biosorption was 57,5 {+-} 0.6% in 1 hours. These results suggest that coffee husk in untreated form can be used in the treatment of radioactive waste liquid containing Am-241. (author)

  9. Silica in Protoplanetary Disks

    Sargent, B A; Tayrien, C; McClure, M K; Li, A; Basu, A R; Manoj, P; Watson, D M; Bohac, C J; Furlan, E; Kim, K H; Green, J D; Sloan, G C


    Mid-infrared spectra of a few T Tauri stars (TTS) taken with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope show prominent narrow emission features indicating silica (crystalline silicon dioxide). Silica is not a major constituent of the interstellar medium; therefore, any silica present in the circumstellar protoplanetary disks of TTS must be largely the result of processing of primitive dust material in the disks surrouding these stars. We model the silica emission features in our spectra using the opacities of various polymorphs of silica and their amorphous versions computed from earth-based laboratory measurements. This modeling indicates that the two polymorphs of silica, tridymite and cristobalite, which form at successively higher temperatures and low pressures, are the dominant forms of silica in the TTS of our sample. These high temperature, low pressure polymorphs of silica present in protoplanetary disks are consistent with a grain composed mostly of tridymite named Ada found...

  10. Multifunctional mesoporous silica catalyst

    Lin, Victor Shang-Yi; Tsai, Chih-Hsiang; Chen, Hung-Ting; Pruski, Marek; Kobayashi, Takeshi


    The present invention provides bifunctional silica mesoporous materials, including mesoporous silica nanoparticles ("MSN"), having pores modified with diarylammonium triflate and perfluoroaryl moieties, that are useful for the acid-catalyzed esterification of organic acids with organic alcohols.

  11. Silica extraction from geothermal water

    Bourcier, William L; Bruton, Carol J


    A method of producing silica from geothermal fluid containing low concentration of the silica of less than 275 ppm includes the steps of treating the geothermal fluid containing the silica by reverse osmosis treatment thereby producing a concentrated fluid containing the silica, seasoning the concentrated fluid thereby producing a slurry having precipitated colloids containing the silica, and separating the silica from the slurry.

  12. Development of ultrafine and pure amorphous and crystalline new materials and their fabrication process

    Yang, Myung Seung; Kim, Y. E.; Kim, J. G.; Gu, J. H. [Korea Atomic Energy Research Inst., Taejon (Korea, Republic of); Yoon, N. K.; Seong, S. Y. [Myongseong Ceramics Co., Taejon (Korea, Republic of); Ryu, S. E. [Paichai Univ., Taejon (Korea, Republic of); Lee, J. C. [Myongji Univ., Taejon (Korea, Republic of)


    Based on an estimation of annual rice production of 5.2 Million tons, rice husks by-production reaches to 1.17 Million tons per year in Korea. distinguished to other corns, rice contains a lot of Si; 10 {approx} 20 % by weight in rice husks calculated as silica. The aim of this research project is to develop technologies for ceramic powders and materials utilizing the silica in rice husks called phytoliths. In this researches of the following subjects were performed; decomposition of the organic components, acid treatments, extraction of the organic matter, effect of gamma-ray irradiation on the acid treatment, plasma treatment, crystallization of silica powder, dispersion of amorphous silica powder, fabrication of ultrafine crystalline fibrous materials.. (author). 18 refs., 5 tabs., 55 figs.

  13. Effects of Rice Straw Silicification and Characters of Extraction Biogenic Silicon on the Degradation of Fibrous Components in Rice Straw

    SHEN Heng-sheng; CHEN Jun-chen; Ni De-bin


    Straw of seven rice varieties with early-, middle- and late maturity was collected from Huazhong Agricultural University in Hubei. A study was carried ont for rice straw in the aspects of the characters of straw silicification and extraction biogenic silica (EBSi), the relationship between characters of EBSi and kinetic characteristics of degradation of fibrous components in fistulated cows, as well as the effect of urea treatment on rice straw desilicification. Although total silica content (ADISi) in rice straw was similar, the efficiency of extraction biogenic silica (EEBSi) and cellulose in early varieties were significantly higher than those in middle (18.9% and 9.1%) and late ones (26.1% and 11.2%). The degradability of EBSi and cellulose of early varieties were higher than those of middle by 70.0% and 17.5%, and of late varieties by 47.8% and 23.7%, respectively. The in sacco degradability and in vitro VFA production of early varieties were also higher than those of middle by 14.5% and 19.0%, and late by 12.9% and 14.8%.Comparing the morphological fractions of the rice straws, EEBSi, cellulose content, and in vitro VFA production were different with the order of blade < sheath < stem. A significant correlation was found between the contents of EBSi and cellulose (r = 0.86), and the two contents were remarkably correlated with the potential straw degradability (a + b) by r = 0.90 and 0.84 respectively. Therefore, EBSi in rice straw was a main factor affecting the potential degradability of rice straw, rather than the ADISi of straw. Urea treatment improved rice straw degradability, degradation rate and potential degradability by 10.8%, 27.9%,and 10.1% respectively, compared to untreated straws.

  14. Structural analysis and transformation of biosilica during lignocellulose fractionation of rice straw

    Pan, Mingzhu; Gan, Xihua; Mei, Changtong; Liang, Yongfeng


    This study focused on the interfacial combination of silica and lignin-polysaccharides during lignocellulose fractionation of rice straw using scanning electric microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD) techniques. Silica was deposited on the exterior surface of rice straw in the form of Si(OR)x, Sisbnd Osbnd Si, SiOx, and Sisbnd C respectively, while not in the form of elemental Si. After delignification and alkalization, silica was deposited on the surface of polysaccharide with a more regular pattern. It is due to that silica reacted with polysaccharide to form SiOx and Si(OR)x during the decomposition of lignin and hemicellulose, leading to the remained framework structure of crystalline cellulose. After the decomposition of polysaccharide, silica was embedded into lignin fragments, and shown as an amorphous opal. For silica-lignin, Sisbnd Osbnd Si was gradually transferred to Si(OR)x instead of Sisbnd C. The capacities of the fractionated components to bind or store silica were in order of lignin > polysaccharides > lipids. Moreover, the fractionated components of rice straw were associated with the different ultrastructural forms of the silica.

  15. Effectiveness of Rice Agricultural Waste, Microbes and Wetland Plants in the Removal of Reactive Black-5 Azo Dye in Microcosm Constructed Wetlands.

    Saba, Beenish; Jabeen, Madeeha; Khalid, Azeem; Aziz, Irfan; Christy, Ann D


    Azo dyes are commonly generated as effluent pollutants by dye using industries, causing contamination of surface and ground water. Various strategies are employed to treat such wastewater; however, a multi-faceted treatment strategy could be more effective for complete removal of azo dyes from industrial effluent than any single treatment. In the present study, rice husk material was used as a substratum in two constructed wetlands (CWs) and augmented with microorganisms in the presence of wetland plants to effectively treat dye-polluted water. To evaluate the efficiency of each process the study was divided into three levels, i.e., adsorption of dye onto the substratum, phytoremediation within the CW and then bioremediation along with the previous two processes in the augmented CW. The adsorption process was helpful in removing 50% dye in presence of rice husk while 80% in presence of rice husk biocahr. Augmentation of microorganisms in CW systems has improved dye removal efficiency to 90%. Similarly presence of microorganisms enhanced removal of total nitrogen (68% 0 and Total phosphorus (75%). A significant improvement in plant growth was also observed by measuring plant height, number of leaves and leave area. These findings suggest the use of agricultural waste as part of a CW substratum can provide enhanced removal of textile dyes.

  16. Combined subcritical water and enzymatic hydrolysis for reducing sugar production from coconut husk

    Muharja, Maktum; Junianti, Fitri; Nurtono, Tantular; Widjaja, Arief


    Coconut husk wastes are abundantly available in Indonesia. It has a potential to be used into alternative renewable energy sources such as hydrogen using enzymatic hydrolysis followed by a fermentation process. Unfortunately, enzymatic hydrolysis is hampered by the complex structure of lignocellulose, so the cellulose component is hard to degrade. In this study, Combined Subcritical Water (SCW) and enzymatic hydrolysis are applied to enhance fermentable, thereby reducing production of sugar from coconut husk. There were two steps in this study, the first step was coconut husk pretreated by SCW in batch reactor at 80 bar and 150-200°C for 60 minutes reaction time. Secondly, solid fraction from the results of SCW was hydrolyzed using the mixture of pure cellulose and xylanase enzymes. Analysis was conducted on untreated and SCW-treated by gravimetric assay, liquid fraction after SCW and solid fraction after enzymatic hydrolysis using DNS assay. The maximum yield of reducing sugar (including xylose, arabinose glucose, galactose, mannose) was 1.254 gr per 6 gr raw material, representing 53.95% of total sugar in coconut husk biomass which was obtained at 150°C 80 bar for 60 minutes reaction time of SCW-treated and 6 hour of enzymatic hydrolysis using mixture of pure cellulose and xylanase enzymes (18.6 U /gram of coconut husk).

  17. Two new isoxazolines from the husks of Xanthoceras sorbifolia Bunge.

    Ge, Hui-Qi; Wan, Guo-Sheng; Wang, Da; Wu, Ji-Ming; Sun, Bo-Hang; Wu, Li-Jun; Gao, Hui-Yuan


    Two new isoxazoline compounds, 1-oxa-2-azaspiro[4.5]dec-2-ene-8β-ol (1) and 1-oxa-2-azaspiro[4.5]dec-2-ene-8α-ol (2), were isolated from the husks of fruits of Xanthoceras sorbifolia Bunge and their structures were determined by spectroscopic analyses, including X-ray crystallography, HRESI-MS, UV, IR, and 1D and 2D NMR (HSQC, HMBC, NOESY) methods. Neither compound showed significant inhibitory effects on butyrylcholinesterase (BuchE) and acetylcholinesterase (AChE), nor the selected tumor cells growth. Based on an online activity prediction program (PASS ONLINE), the structures with isoxazoline skeletons were found to show potential anti-asthmatic (AM) and anti-anaphylaxis (AP) activities; moreover, compounds 1 and 2 were predicted to possess high affinities for many enzymes involved in AM and AP according to the RCSB Protein Data Bank. High-affinity binding to phosphodiesterase IV (PDE-4), an important inflammatory modulator in asthma, was demonstrated experimentally, beside that, the predicted structures based on compounds 1 and 2 were analyzed for PDE-4 interactions using the molecular docking methodology of Discovery Studio 3.0 (DS 3.0). The predicted structure 2A-6 exhibited much higher affinity and stability of PDE-4 binding than the clinical PDE-4 inhibitor rolipram.

  18. Antimalarial Activity of Cocos nucifera Husk Fibre: Further Studies

    J. O. Adebayo


    Full Text Available In this study, the antimalarial and toxicity potentials of husk fibre extracts of five Nigerian varieties of Cocos nucifera were evaluated in vitro. The only active extract fraction, West African Tall (WAT ethyl acetate extract fraction, was then evaluated for its phytochemical constituents, antimalarial and toxicity potentials at varying doses (31.25–500 mg/kg body weight using various organ function indices. The results revealed that WAT ethyl acetate extract fraction (WATEAEF contained alkaloids, tannins, and flavonoids and was active against Plasmodium falciparum W2 strain maintained in continuous culture, with a selectivity index of 30.3. The same extract fraction was active in vivo against Plasmodium berghei NK65, causing more than 50% reduction in parasitaemia on days 4 and 6 after inoculation at various doses administered. WATEAEF did not significantly alter (P>0.05 function indices of the liver and cardiovascular system at all doses administered but significantly increased (P<0.05 plasma creatinine concentration at 250 and 500 mg/Kg body weight compared to controls. The results of this study suggest that WATEAEF possesses antimalarial activity and may not adversely affect normal liver function nor predispose subjects to cardiovascular diseases but may impair normal kidney function at higher doses. Further studies are underway to isolate the active principles.

  19. Pyrolysis kinetics of Melon (Citrullus colocynthis L.) seed husk

    Nyakuma, Bemgba Bevan


    This study is aimed at investigating the thermochemical fuel characteristics and kinetic decomposition of melon seed husks (MSH) under inert (pyrolysis) conditions. The calorific value, elemental composition, proximate analyses and thermal kinetics of MSH was examined. The kinetic parameters; activation energy E and frequency factor A for MSH decomposition under pyrolysis conditions were determined using the Kissinger and isoconversional Flynn-Wall-Ozawa (FWO) methods. The values of E for MSH ranged from 146.81 to 296 kJ/mol at degrees of conversion {\\alpha} = 0.15 to 0.60 for FWO. The decomposition of MSH process was fastest at {\\alpha} = 0.15 and slowest at {\\alpha} = 0.60 with average E and A values of 192.96 kJ/mol and 2.86 x 1026 min-1, respectively at correlation values of 0.9847. The kinetic values of MSH using the Kissinger method are E = 161.26 kJ/mol and frequency factor, A = 2.08 x 1010 min-1 with the correlation value, R2 = 0.9958. The results indicate that MSH possesses important characteristics ...

  20. The root system of the husk tomato (Physalis ixocarpa Brot.

    Juan Mulato Brito


    Full Text Available The husk tomato (Physalis ixocarpa Brot. is widely cultivated in central Mexico, and may be grown in countries with a temperate climate. The experiment was set up during the dry period of the year (average weekly temperature 17-22°C in the State of Morelos, Mexico, using the cv. 'Rendidora' in loamy clay soil and furrow irrigation. The roots were investigated by the pinboard method modified by Garcia Blancas and Grajeda Gómez (in print, partly adapted by us for quantitative estimation of root systems. Two plants were investigated every second week. They had a well developed tap root. Most of their lateral roots were found in the superficial soil layer, 0-20 cm. The root dry mass was also concentrated near the central axis of the plant. The majority of root apices were, however, found in the soil cylinders 10-40 em from the central axis. During the senescence of the aerial part (14th week after emergence the root system lost a large part of its small roots. The modification of the pinboard method, by Garcia Blancas and Grajeda Gómez (in print permited us investigating the root systems with very simple tools, in situ.