Characteristics Of Rice Husk Ash Research Articles

Tuning the textural properties of biomass-derived nanocrystallized BEA for acetyl functionalization of anisole

The synthesis of a highly active zeolite beta catalyst for acetyl functionalization of anisole by utilizing the silica precursor obtained from Rice husk is a promising approach for mitigation of agricultural waste. The influence of combustion temperature(CT) (300, 500, 700, and 900 °C) on the characteristics of Rice husk ash was investigated. The C52H obtained at a medium CT (500 °C) has a high surface area compared to the C72H indicates that, merging of smaller crystallites of amorphous silica to form crystalline silica with larger crystallites by applying more thermal energy when CT ≥ 700 °C. The PS-5 catalyst derived from C52H possess high surface area (332 m2/g) and smaller crystallite size (14.8 nm) compared to the PS-7 obtained from C72H, which shows the lower surface area (131.5 m2/g) with a larger crystallite size (25.6 nm). Solid-state NMR studies and NH3-TPD analysis reveals that PS-5 catalyst possessing higher acidity compare to both PS and PS-7. The activity studies confirm that the PS-5 catalyst exhibited superior catalytic activity (>98.0%) compared to PS (conventional) and PS-7 catalysts, making it a potential candidate for continuous production of aromatic ketones acylation reactions.

Rice husk ash as sorbent for solid phase extraction of diclofenac, ibuprofen and carboplatin residues from waters

Carboplatin, ibuprofen and diclofenac are among drugs classified as emergent pharmaceutical contaminants that impact negatively the environment. Development of affordable procedures for their quantification and removal from waters is gained interest in the scientific community. The present study was aimed at the characterization of rice husk ash as sorbent for the solid phase extraction of mentioned drugs in waters. Optimal sorbent dose, pH dissolution and contact time were selected. Up to the best of our knowledge, the good performance of rice husk ash for extraction of carboplatin, ibuprofen and diclofenac from aqueous dissolutions is demonstrated for the first time in the present study, achieving a maximum sorption capacity of 5.843 mg.g−1, 2.321 mg.g−1 and 2.316 mg.g−1, respectively, which are higher than those reported for others pharmaceutical products with husk rice ashes. Kinetic of sorption was well modeled by a Lagergren pseudo first order model for diclofenac and by a pseudo second order model of Ho for ibuprofen and carboplatin. Sorption at equilibrium conditions was well modeled by Freundlich and Toth isotherms for diclofenac and ibuprofen, while Sips, Toth and Dubinin-Radushkevich isotherms adjusted well for carboplatin. Kinetic and at equilibrium conditions studies confirmed the high complexity of involved sorption mechanisms in the three adsorbate/rice husk ash systems considered.

Experimental Investigation of Microstructure and Phase Characterization of Rice Hush Ash (RHA) for Potential Utilization in Metal Matrix Composites

Recent trends in material research and development of composite materials are geared towards reducing cost, recycling and ensuring environmental sustainability. Agricultural waste derivatives have proven to be an alternative or complimentary reinforcement material in the development of metal matrix composites. The current work is an investigation of the microstructure and phase characterization of rice husk ash (RHA) obtained through open air burning. Scanning electron microscopy (SEM) equipped with electron dispersive spectrometry (EDS) was used for the microstructural examination, X –ray fluorescence (XRF) forthe mineralogical composition and X –ray diffraction (XRD) for the determination of phases present. Results revealed that RHA is highly siliceous with 93.8% SiO2, highly porous and fibrous material with a wide surface area. EDS profile confirmed the presence of SiO2and Al2O3. The XRD pattern revealed the presence of quartz, crystabalite and anorthite phases in the RHA. Silica is a hard substance with strong covalent bonds similar to diamond with hardness rating of 7 on Mohs scale and melting point of 1713OC. Thus,RHA can be suitable used as a reinforcing material in the development of metal matrix composites for automotive components

Effect of sonication and reflux treatment on silica characteristics of rice husk ash as raw material for dental pulpotomy

Abstrak. Penelitian ini bertujuan untuk mengekstraksi dan memunikan silika dari abu sekam padi (ASP) dan melihat karakteristik silika yang dihasilkan apabila diberi perlakuan sonikasi dan refluks. Metode yang digunakan dalam penelitian ini adalah sol-gel menggunakan pelarut NaOH dan HCl kemudian diberi perlakuan sonikasi dan refluks serta pencucian untuk meminimalisir keberadaan natrium pada silika yang dihasilkan. Berdasarkan penelitian yang dilakukan, presentase silika dari metode sonikasi dan refluks adalah 96,4% dan 93%. Silika yang dihasilkan dari kedua metode mempunyai fase amorf dengan puncak melebar pada (2θ) 22º. Spektra FTIR antara kedua metode tidak menunjukkan perbedaan dengan puncak pada pita serapan 470 cm-1, 802 cm-1, dan1103 cm-1 yaitu vibrasi dari Si-O siloksan (≡Si-O-Si≡). Pita serapan 3448 cm-1 adalah vibrasi ulur –OH dari silanol (≡Si-OH). Citra SEM menunjukkan bentuk yang berbeda pada silika yang dimurnikan dengan metode sonikasi dan refluks yaitu agregasi bulat teratur dan tak beraturan. Ukuran partikel dari silika dari metode sonikasi adalah 0,4448 µm. Berdasarkan hasil karakterisasi yang dilakukan, dapat disimpulkan bahwa ekstraksi silika sebagai bahan baku pembuatan material pulpotomi dapat efektif dilakukan menggunakan metode sol-gel dan dimurnikan menggunakan sonikasi. Abstract. This study aims to extract and purify silica from rice husk ash (RHA) and see the characteristics of the silica produced when treated with sonication and reflux. The method used in this study was sol-gel using NaOH and HCl solvents and then treated with sonication and reflux and washing to minimize the presence of sodium in the silica. Based on the research, the percentage of silica from the sonication and reflux method was 96.4% and 93%, respectively. Silica produced by both methods has an amorphous phase with a broad peak at (2θ) 22º. The FTIR spectra between the two methods showed no difference with peaks in the absorption bands of 470 cm-1, 802 cm-1, and 1103 cm-1, namely the vibration of Si-O siloxane (≡Si-O-Si≡). The absorption band of 3448 cm-1 is the –OH stretching vibration of silanol (≡Si-OH). SEM images show different shapes of silica purified by sonication and reflux methods, namely regular aggregation, and irregular form. The particle size of silica from the sonication method is 0.4448 µm. Based on the results of the characterization carried out, it can be concluded that the extraction of silica as a raw material for the of pulpotomy can be effectively carried out using the sol-gel method and purified using sonication.

Effects of basalt fibres on strength and permeability of rice husk ash-treated expansive soils

The application of stabilised soil in agricultural construction works such as shallow foundation fills and subgrade material for farm roads is in demand due to the improved geotechnical properties. This study focused on improving the compressive capabilities and the permeability characteristics of rice husk ash (RHA)-treated clayey soils using basalt fibre. Basalt fibres are made from naturally occurring basalt rock, yet their use in soil stabilisation has not been realised due to limited research for its validation in ground stabilisation. Essential variables in the stabilised soil matrix included basalt fibre length (3 mm, 6 mm, and 12 mm), RHA percentages (5%, 10%, and 15%), and cement percentage (3%). In addition, the optimum moisture content of each admixture was determined by standard proctor compaction tests and reduced by 3% to prepare the specimens for unconfined compression strength test, constant head permeability test, and scanning electron microscope (SEM) test. It was observed that the unconfined compression strength of the RHA-basalt fibre stabilised clayey significantly increased when the specimens wet cure for 28 days. Similarly, adding fibres into the soil improved the permeability coefficient. The SEM test showed a porous morphology that increased permeability. Furthermore, through SEM, the randomly oriented basalt fibres’ portrayed the reinforcing phenomenon related to improved compressive strength and sufficient bearing capacity to support structures built upon this class of soils.

Particle Size and Microstructure Characterization of Uncontrolled Burning Rice Husk Ash (RHA) as Pozzolanic Material

RHA has been the subject of investigation for its pozzolanic activity that heavily linked to the controlled temperature burning process in order to achieve amorphous form of silica. This paper present the characterization of RHA that was taken directly from the boiler of rice mill with uncontrolled burning temperature. Particle size analysis revealed grinding process of RHA could significantly curb the diameter size and increased specific surface area. Microstructure analysis suggest that RHA is very porous and EDX test showed the chemical content of RHA. The prospect of using uncontrolled burnt RHA as part of construction material is feasible.

Strength performance of high-grade concrete using rice husk ash (RHA) as cement replacement material

Rice husk are agricultural waste acquired through the rice remedy method, whilst rice husk is about 22% of the weight of rice. The waste is used as a gas in leaching steps to produce streams.25% of the size of husk is turned into particles acknowledged as rice husk waste (RHA), which is another waste. The physical and chemical characteristics of rice husk ash (RHA) are analyzed, as well as the strength of composite concrete containing the same ash. The properties of the fresh concrete were compressive, split tensile and flexural strengths including workability, flow, setting times. Notwithstanding consequences for the qualities by RHA and the water concrete proportion, the properties of RHA concrete were likewise differentiated and those of Portland cement concrete have control over and silica concrete.The test results show that RHA is highly pozzolonic at 5%,7.5%,10%,12.5% and15% and can be used in the production of high performance cement as an additional cementing material. Although the super plasticizer and the air work training admixture require a higher dose than control concrete and silica fume concrete, a satisfactory slump, air content and set time can be used in the production of RHA concrete. Compared to the control concrete, the compressive strength of RHA concrete was higher in various ages up to 7 days and 28 days.

Elemental Characterization of Rice Husk Ash from Local Rice Species in South Eastern Nigeria

Heavy metals such as Cr, Zn, As, Pb and Cu can be hazardous to health and the environment. The focus of this study is to investigate the trace metal constituents of rice husk ash (RHA) from Ikwo and Izzi rice clusters. RHA of Izzi CP, R8 and Ikwo CP rice husk species were sampled. Elemental characterization was done using X-ray fluorescence method. A total of 14 elements (K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Rb, As, Br, Sr and Ga) were detected in the rice husk species except in Izzi CP where Ga was not detected. The concentration of these elements in weight percent (wt. %) were compared with literature. Elements like, K, Ca, Fe, and Mn were found to be in negligible concentrations in all the samples while Ga, Rb, Cu, Cr, Zn, As and Ni were found to be well above the literature values. The X-ray fluorescence analysis of the samples showed that some toxic heavy metals like Cr, As, Ni, and Cu were of high concentrations compared to literature which for health reasons are not advisable to have long term exposure.

Optimization of nanostructured/nano sized rice husk ash preparation

The objective of the study is developing a procedure for production and characterization of rice husk ash (RHA). The effects of rice husk (RH) amount, burning/cooling conditions combined with stirring on producing of RHA with amorphous silica, highest SiO2, lowest loss on ignition (LOI), uniform particle shape distribution and nano structured size have been studied. It is concluded that the best amount is 20 g RH in 125 ml evaporating dish Porcelain with burning for 2 h at temperature 700 °C combined with cooling three times during burning to produce RHA with amorphous silica, SiO2 90.78% and LOI 1.73%. On the other hand, cooling and stirring times affect the variation of nano structured size and particle shape distribution. However, no crystalline phases were found in RHA in all cases. Results proved that the Attritor ball mill was more suitable than vibration disk mill for pulverizing nano structured RHA with 50% of particle size (D50) lower than 45 mm and 99 % of particle size (D99) lower than 144 mm to nanosized RHA with D50 lower than 36 nm and D99 lower than 57 nm by grinding time 8.16 min to every 1 g RHA without changes in morphousity of silica.

Characterization of rice husk ash obtained from an industrial source

Chemical, physical and mineralogical characterization of an industrial rice husk ash is reported and the differences with ash typically obtained by laboratory combustion of husks were highlighted. Valorization of industrial ash was targeted by controlling the combustion temperature of rice husks at 600 °C, 650 °C, 700 °C and 750 °C in an atmospheric fluidized bed industrial boiler of a paper mill. The other parameters were ash sampling points (air-preheater, economizer and electrostatic-precipitator) and the ash processing condition (as-received and ground). Irrespective of the burning temperature or sampling point, all ashes had a cellular microstructure with a high specific surface area (25 m2/g − 50 m2/g), silica content was greater than 80% with the amorphous fraction being larger than 90%. Pozzolanic reactivity of ground ash for the entire burning temperature range of 600 °C -750 °C was acceptable and a 15% replacement of cement with the processed ash in blended mortars yielded optimum strength and flow performance.

Mechanical and microstructural characterization of rice husk ash and Al2O3 nanoparticles modified cement concrete

Waste and by-product materials both in their macro and micro-sizes are nowadays gaining more importance and consideration for their use as a partial substitute of the virgin concrete s constituents. Nanoparticles have now also gained widespread recognition and used in various construction applications, especially cement-based materials. The present paper examines the impacts of a combination of Al2O3 nanoparticles along with Rice Husk Ash (RHA) on both mechanical properties (Flexure, Splitting tensile and Compressive) strengths and durability properties, including resistance to hydrochloric acid attack and chloride permeation. RHA substituted Portland cement (PC) at a fixed amount of 10%, and Al2O3 nanoparticles have been utilized as a partial substitution of PC at 1%, 2%, 3%, and 4%. Surface morphology and microstructure of modified cement concretes were assessed by means of the Scanning Electron Microscope (SEM). The results revealed that Al2O3 nanoparticles have double effects as a filling material. As a reactive one, increasing contribution in the volume of calcium silicate hydrates (C-S-H) formed thereby increases the strengths and durability properties of concrete material. It has also been found that 3% content of Al2O3 nanoparticles is the optimum content to substitute part of the cement leading to the greatest mechanical and durability properties enhancement. The combination of up to 3% Al2O3 nanoparticles along with 10%RHA to design modified cement concretes with enhanced strength and durability performances have revealed to be efficient and productive for eco-friendly concrete material.

Characteristics of Rice Husk Ash – Sodium Aluminate Geopolymer at Elevated Temperature

This investigation was focused on the effect of elevated temperature on rice husk ash (RHA) geopolymers activated with sodium (Na) aluminate. Geopolymers were synthesised by varying the silicon (Si...

Obtención y caracterización de materiales adsorbentes a partir de cascarilla de arroz

Agricultural waste management for the production of materials with specific uses is important for the remediation of certain environmental problems. Rice husk, an abundantly agricultural waste in Colombia, could be a low cost adsorbent for molecules such as dyes or heavy metals in effluent streams. In this research, we address the production and characterization of rice husk ash obtained by chemical activation with phosphoric acid as an adsorbent material. The physical-chemical properties of the materials were evaluated using different characterization techniques, such as close analysis, iodine number, adsorption of methylene blue, adsorption-desorption of nitrogen, analysis of the functional groups on the surface of the adsorbent through infrared spectroscopy (ftir), as well as an analysis of the morphology with scanning electron microscopy (sem). The materials have a surface area around 320 m2/g, which decreases depending on the amount of acid used in the activation. The pore size in the studied samples ranged between 4 and 12 nm, which suggest that mesoporous solids were obtained. Regarding the adsorption of methylene blue, results show that the production of the activated ashes from rice husk as adsorbent materials is viable, presenting a new opportunity for the use of materials considered as agricultural waste.

The study of adsorption efficiency of rice husk ash for removal of phenol from wastewater with low initial phenol concentration

This research work aimed to assess the adsorption efficiency of rice husk ash for removal of phenol from wastewater. The authors studied the morphology and characterization of rice husk ash using SEM, FTIR, XRD and BET analyzers and carried out the batch experiments to evaluate the removal percentage of phenol with variation of pH (3–11), adsorption time (30–270 min), adsorbent dose (0.5–4.0 gm/L), phenol concentration (5–20 mg/L) and temperature (25–35 °C). It was observed that the maximum removal reached as high as 95%. The testing of kinetic models showed that the second-order model was better than the first-order model. Elovich model showed that the adsorption process was chemical, Reichenberg model showed that adsorption occurred because of film diffusion, Furusawa and Smith model showed that phenol moved faster from bulk to solid stage, Boyd model indicated that the process supported chemisorptions, and Fick’s model implied that film and intraparticle diffusion took 45 min and 135 min, respectively. Testing of isotherm models indicated that Langmuir, Freundlich and Temkin models were all supportive of equilibrium data. The Dubinin–Radushkevich isotherm indicated that the process was explained by feeble physical adsorption. The isothermal study indicated that the process was random, endothermic and spontaneous. Although some studies had been done for removal of phenol using rice husk ash in the past, this research had covered the extensive works on the characterization of the adsorbent, extent of phenol removal with the variation of several process variables, and testing of several models in the areas of kinetics, isotherms, and thermodynamics. Further, the novelty of this research was that the experiments were carried out for treatment of wastewater exclusively with low initial phenol concentrations so that the results can be effectively applied in several small- and medium-scale industries at lesser costs, particularly in the Third World countries.

Synthesis and Characteristics of Rice Husk Ash Based Magnetic Hydrogel (RHA-MH) for H2 Generation

Abstract: In this study, magnetic hydrogel was synthesized from rice husk ash (RHA-MH) using two methods, i.e. sol-gel and cross-linking methods. The prepared rice husk ash based magnetic hydrogel (RHA-MH) were used as a catalyst for H2 generation through hydrolysis of sodium borohydride (NaBH4). Factors effecting hydrolysis reaction such as effect of RHA calcination temperature and method used to synthesis the catalyst were investigated. The RHA-MH1200 synthesised via cross-linking and sol-gel methods (using RHA calcined at 1200°C) shows the shortest time taken (5.64 min and 11.18 min, respectively) to produce 40 mL of H2 gas as compared to RHA-MH600 (i.e. 10.47 min and 13.18 min respectively, for both methods using RHA calcined at 600°C). The prepared and spent RHA-MH were also characterized using Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray (EDX) analysis. From SEM image, it could be concluded that silica (SiO2) could successfully be utilized as the supporting material for stabilizing magnetic iron oxide (Fe3O4) nanoparticles. The SEM image also showed that the overall structure was relatively porous. Moreover, the SEM images of magnetic hydrogel before and after the hydrolysis of NaBH4 exhibited similar physical structures. Keywords: Hydrogen; NaBH4 hydrolysis; Rice husk ash based magnetic hydrogel (RHA-MH); Sol-gel; Cross-linking

Preparation and characterization of rice husk ash for using as a filler in natural rubber

Abstract In this study, rice husk ash (RHA) and commercial silica were used as reinforcing fillers in natural rubber (NR). XRF, FTIR, SEM and particle size analysis were used to characterize RHA and commercial silica. Silica contents in RHA and commercial silica were 91.413% and 98.693%, respectively. Particle size of RHA was larger than that of commercial silica. Cure characteristics, mechanical properties and morphology of NR reinforced with RHA and commercial silica were compared. RHA/NR composite showed shorter scorch time and cure time when compared to silica/NR composite. Mechanical properties of commercial silica/NR composite were higher than those of RHA/NR composite. Silane coupling agent (Si69) increased mechanical properties but reduced scorch time and cure time of the NR composites. SEM results revealed that Si69 improved the compatibility between the filler and NR matrix.

Microstructure and wear characterization of rice husk ash reinforced copper matrix composites prepared using friction stir processing

Rice husk ash (RHA) is an economical reinforcement to improve the poor wear behavior of pure copper. This work concentrates on the preparation of Cu/RHA (0,6,12,18 vol.%) copper matrix composites (CMCs) by friction stir processing (FSP). Grooves were machined on the copper plates to deposit RHA particles and were friction stir processed at a chosen set of process parameters. The microstructure was studied using optical, scanning and transmission electron microscopy. The wear behavior was estimated using a pin-on-disc apparatus. The micrographs revealed a uniform dispersion of RHA particles in the copper matrix. Neither aggregation nor segregation was observed. The variation in the dispersion of RHA particles at different regions within the stir zone was negligible. A good interfacial bonding between RHA particles and the copper matrix was realized. Many RHA particles encountered break up. A remarkable grain refinement was achieved due to dynamic recrystallization and pinning effect of RHA particles. The wear behavior under dry sliding condition was presented in detail.

Removal of metal impurities in rice husk and characterization of rice husk ash under simplified acid pretreatment process

Acid pretreatment plays an important role in the preparation of amorphous silica with high activity and high specific surface area before combustion process. However, some limitations and problems exist in the pretreatment process of previous literatures. On the basis of this, this work is aimed at simplifying the acid pretreatment process and combustion condition, which could present a more advantageous process for practical industrial applications. Then the removal percentage and behavior of metal impurities in rice husk is studied by ICP‐OES, and effects of acid pretreatment on properties of rice husk ash (RHA) at various combustion temperatures are comprehensively investigated in comparison with previous results by scanning electron microscope (SEM), X‐ray fluorescence (XRF), X‐ray diffractometer (XRD), and surface analyzer. The results suggest that the removal degree of each metal is various due to each chemical form in rice husk, of which removal percentage of K is especially remarkable. The contributions of simplified acid pretreatment to the properties of RHA are equally prominent: smaller nanoscale particles, higher purity, and specific surface area of above 200 m2/g. In addition, the pretreatment can also eliminate the crystallization and keep the high activity of RHA in combustion temperature range of 600–900°C. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 830–837, 2017

OPTIMIZATION OF IMPORTANT PROCESS PARAMETERS FOR THE REMOVAL OF Cr(VI) BY A MODIFIED WASTE MATERIAL

This paper highlights the utility of rice husk ash for the adsorption of Cr(VI) ions from aqueous solutions. Rice husk ash (RHA) is produced when rice husk is burnt for various purposes. Application of Treated Rice Husk Ash (TRHA) as an adsorbent for the removal of Cr(VI) from aqueous solutions has been investigated. For this purpose, RHA was thermally treated. RHA and treated RHA (TRHA) were characterized by XRD, SEM and FTIR to investigate the effect of treatment on the nature and surface characteristics of RHA. The experiments were carried out in batch mode. A three factor, three-level Box-Behnken experimental design was employed for optimizing important process parameters for adsorption of Cr(VI) on TRHA. The effect of three parameters, initial Cr(VI) ion concentration (500-1000 g/L), temperature(25-450C) and initial pH(2.0-8.0) of solution on the removal process was determined. Fifteen experiments designed by Box-Behnken design (BBD) were carried out. It was observed from this investigation that the percentage removal efficiency is significantly influenced by initial concentration, temperature and pH of solutions. The optimum values of the variables were found to be 750 g/L, 25 0C and 2.0 for initial chromium ion concentration, temperature and pH respectively. The experimental values were in good agreement with predicted values and the model developed was highly significant. Present study revealed that TRHA is an economically viable adsorbent for the removal of Cr(VI) from aqueous solutions.

La ceniza de cascarilla de arroz y su efecto en adhesivos tipo mortero

En este estudio se presenta una caracterización de la ceniza de cascarilla de arroz a un tamaño de partícula adecuado para su desempeño como agregado fino en adhesivos tipo mortero para colocación de baldosas cerámicas, debido al alto porcentaje de sílice en su composición química. Se analizan las propiedades físicas y químicas de los agregados y el comportamiento mecánico de fluidez y resistencia a la tracción de los morteros obtenidos con reemplazo parcial de arena en porcentajes desde 5% hasta 25%, proponiendo así el empleo de los residuos de ceniza de cascarilla de arroz y presentando una alternativa de disminución a la explotación de arena, la cual genera impactos graves al medio ambiente. Los resultados muestran que un porcentaje de reemplazo de la arena por ceniza de cascarilla de arroz de 20% produce fuerzas de tracción comparables con las obtenidas para adhesivos comerciales.