Waste Rice Husk Ash Research Articles

Synthesis Of Paramagnetic Merkapto Silica Hybrid From Rice Husk Ash For Ag(I) Adsorben

A study has been conducted on the synthesis of paramagnetic mercapto silica hybrids as metal adsorbent of Ag(I). The aim of this study was to synthesis paramagnetic mercapto silica hybrid from rice husk ash waste, knowing the characteristics of paramagnetic mercapto silica hybrid from rice husk ash waste, and to determine the effect of pH, metal ions concentration, and the contact time on the value of adsorption capacity (Q). Based on the results of the study, it was found that paramagnetic mercapto silica hybrids can be synthesized from the rice husk ash waste. Characterization using FTIR spectroscopy showed that silanol (Si-OH), siloxan (Si-O-Si), -SH, and Fe-OH functional groups, and characterization of paramagnetic mercapto silica hybrid structures using XRD to show crystalline compounds with a position value of 2θ = 35.4 which showed that the magnetite material of Fe3O4 was coated by silica. Paramagnetic mercapto silica hybrids from rice husk waste can be used as adsorbent of Ag (I) metal at optimum conditions of pH 3, contact time of 120 minutes, and adsorption capacity of 392.01 mg/g. The suitable isotherm model is the Freundlich isotherm model which means the absorption of metal Ag (I) occurs physically, while adsorption of kinetics followed the pseudo II order kinetic model with a value of k = 3.01 g.mg-1 minute-1.

KARAKTERISTIK SORPSI ISOTERMIS PADA APLIKASI SILIKA (SiO2) SEBAGAI ANTICAKING AGENT TEPUNG BUMBU

Silica dioxide is one of anticacking agent as food additive. It can be encountered in nature, especially from rice husk ash waste. The objective of this study was to obtain rice husk-based silica and find out its characteristics, then apply it in seasoned flour to examine its characteristics during the storage period based on sorption isotherm. This research consisted of two stages. The first stage was silica isolation from rice husk, it was started by washing rice husk using 5% citric acid as pre-treatment followed by 800oC combustion for 30 minutes, then continued by analyzing the characteristics of both rice husk-based silica and synthetic silica as a comparison. Last stage was formulating seasoned flour with 0.5% and 1% both rice husk-based silica and synthetic silica as anticacking agent, followed by observing the phenomenon during storage period to illustrate its sorption isotherm curve. Characterizations using XRD analysis showed both synthetic silica and rice husk-based silica hadamorphous structure. SEM-EDX analysis showed that there were 25.52% elements of C in rice husk-based silica and 10.23% of C and 1.29% of N formed in synthetic silica. Addition of both rice husk-based and synthetic silica onto seasoned flour indicated the occurrence increasing number of critical and equilibrium moisture content, water activity, and ash content. Based on characteristic of sorption isotherm curve, the 1% addition of rice husk-based silica on seasoned flour formulation gave optimum number of primary, secondary, and tertiary boundary water fractionsof 7.35%, 20.04%, 70.18%,respectively.Keywords: anticaking agent, rice husk, silica, silica dioxide and synthetic silica

Green silica-based ceramic hollow fiber membrane for seawater desalination via direct contact membrane distillation

Abstract In this work, green silica-based ceramic hollow fiber membranes (CHFMs) derived from rice husk ash waste were successfully prepared via phase inversion and sintering technique. Prior to the fabrication, rice husk waste was converted into amorphous and crystalline silica-based rice husk ash (ARHA and CRHA). The surface of CHFMs could be easily modified to become hydrophobic by grafting with a fluoroalkylsilane (FAS) agent. The CHFMs were characterized before and after grafting using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), measurement of contact angle and liquid entry pressure of water (LEPw), and three-point bending test. The pore size and the porosity of the membrane surface were also evaluated using mercury intrusion porosimetry (MIP). Lotus-leaf structure formed at the surface of HFMs by grafting, leading to a high contact angle of >150°. Direct contact membrane distillation (DCMD) performance of membrane after grafting was conducted for 200 h using the synthetic seawater of various NaCl concentrations at different feed temperatures. The experimental results show that the permeate flux decreased with the increasing feed concentration, whereas it was enhanced with the increasing feed temperature. A high water flux of 38.2 kg/m2 h and salt rejection up to 99.9% were obtained by CHFM prepared from CRHA (CHFM/CRHA).

Effect of waste rice husk ash (RHA) on structural, thermal and acoustic properties of fired clay bricks

A potential use of rice husk ash (RHA), a residual of brick firing process on the manufacturing of fired clay bricks was identified. Although addition of waste RHA may influence the structural properties of building materials, it is not clear how this affects on thermal and acoustic performances. For these reasons, industrial scale productions of fired-clay bricks were used for experimental investigation on structural, thermal and acoustic properties of the fired clay bricks manufactured with the waste RHA.Clay was mixed manually with six different RHA contents: 0%, 2%, 4%, 6%, 8% and 10%, by weight of the brick. Bricks having the dimensions of 195 mm × 95 mm × 50 mm were prepared and fired in an industrial scale kiln. Physical properties (Atterberg's limits, particle size distribution), chemical composition of materials, structural properties (compressive strength), thermal performance and acoustic performance of the bricks were evaluated.Clay mixed with waste RHA improved the mixture for brick manufacturing. Lightweight bricks produced with waste RHA show the optimum compressive strength of 3.55 N/mm2, (32.7% improvement compared to the conventional fired clay brick) and water absorption of 19% at 4% RHA, implying that the RHA has a potential to improve the structural properties. At 4% RHA, the brick shows 6 °C in-door temperature reduction and 10 dB noise reduction compared with that of the conventional fired clay brick. Waste RHA added clay brick showed better structural, thermal and acoustic properties compared with the conventional clay bricks, while managing waste RHA by decentralization, which will be a remarkable environmental and ecological achievement.

Synthesis of zeolite from rice husk ash waste of brick industries as hydrophobic adsorbent for fuel grade ethanol purification

A lot of researchers have devoted on ethanol utilization as renewable energy to substitute petroleum based gasoline. When ethanol is being used as a new fuel candidate, it should have at least of 99.5% purity. Usually produced via sugar fermentation process, further purification of ethanol from other components in fermentation broth to obtain its fuel grade is a crucial step. The purpose of this research is to produce synthetic zeolite as hydrophobic adsorbent from rice husk ash for ethanol-water separation and to investigate the influence of weight, adsorption time and initial ethanol concentration on zeolite adsorption capacity. This research consisted of rice husk silica extraction, preparation of hydrophobic zeolite adsorbent, physical characterization using SEM, EDX and adsorption test for an ethanol-water solution. Zeolite with highest adsorption capacity was obtained with 15: 1 alumina silica composition. The best adsorption condition was achieved when 4-gram hydrophobic zeolite applied for adsorption of 100 mL of 10% (v/v) ethanol-water solution for 120 minutes, which resulted in ethanol with 98.93% (v/v) purity. The hydrophobic zeolite from rice husk ash is a potential candidate as an efficient adsorbent to purify raw ethanol into fuel grade ethanol. Implementation of this new adsorbent for ethanol production in commercial scale may reduce the energy consumption of that usually used for the distillation processes.

Effect of waste rice husk ash on structural, thermal and run-off properties of clay roof tiles

Rice Husk Ash (RHA), a waste from firing process of clay products, has no proper usage. For this study, roof tile specimens were manufactured by replacing clay with different RHA percentages (i.e., 0%, 5%, 10%, 15% and 20%) in an industrial scale plant, so as to determine the effect of waste RHA from a brick firing process on structural, thermal properties and run-off qualities of clay roof tiles. For 10% replacement of clay with RHA, transverse breaking load was increased by 45.97% indicating higher ductility compared with that of the conventional tiles. Bulk density is reduced with the percentage of RHA added, promising a light-weight roof tile, a favourable tile for a roofing material. With increasing RHA content, water absorption increases. RHA replacement up to 15% is desirable, satisfying the water absorption limit according to standards. RHA replacement up to 20% doesn’t affect on the water penetration property. RHA mixed roof tiles can reduce the indoor temperature, feeling more comfortable for inhabitants. Collected runoff coming along the 10% RHA mixed clay roof tiles has a pH value of 7.22 and total solid concentration of 118.67mg/L, indicating RHA mixed roof clay tile will not cause any severe impact on the runoff. Hence this harvested runoff can still be utilized for non-potable activities while enhancing the strength and thermal properties of clay roof tiles.

Comparative study on open air burnt low- and high-carbon rice husk ash as partial cement replacement in cement block production

This study analyzes the feasibility of using high-carbon content rice husk ash waste generated from open air burning of rice husk, as secondary raw materials in the manufacture of cement blocks. Solid masonry blocks having the size of 215mm × 105mm × 65mm, were cast with the mix proportion of 1:5 cement and sand. Blocks were manufactured with two types of rice husk ash (RHA); low-carbon content RHA and high-carbon content RHA. Cement blocks, at four different RHA replacement levels of 5%, 10%, 15% and 20% were prepared for low and high-carbon RHA as partial cement replacement. Testing was included for workability (water/binder ratio and setting time), strength (compressive, flexural bending and splitting tensile) and durability (water absorption, sorption, acid attack resistance and alkaline attack resistance). Results from this test results indicate that the workability, mechanical and durability characteristics of low-carbon RHA cement blocks slightly better than that of high-carbon RHA cement blocks. However, both RHA replacement cement blocks satisfy the limit recommended by standards. Even, high-carbon RHA replacement cement block does not vastly improve the strength or durability properties, the economic and environmental benefits encourage to use high-carbon RHA in cement block production.

Strength and microstructure properties of spent coffee grounds stabilized with rice husk ash and slag geopolymers

This paper investigates the strength and microstructure properties of spent coffee grounds stabilized with rice husk ash and slag geopolymers to produce a green construction subgrade material. Spent coffee grounds (CG) and rice husk ash (RHA) are organic wastes derived from agricultural products. CG is the residue from ground coffee beans. RHA is a by-product from the burning rice husk used to generate electricity. Ground granulated blast furnace slag (S) is a waste by-product derived from steel production. RHA and S were used as geopolymeric precursors (P). This study provides an insight on the long-term strength performance and microstructural formation of geopolymers synthesized from agricultural waste products. The influence factors studied were liquid alkaline activator content (L), RHA content, S content, temperature and curing time. By observing the strength development of CG-RHA geopolymers for up to 90days, it was found that elevated temperature curing was needed for these CG:RHA geopolymers to develop long-term strengths. Test results show that an optimum mix of CG:RHA:S 70:20:10 cured at 50°C can achieve an Unconfined Compressive Strength (UCS) of 2MPa after 90days of curing. The outcome of this research will enable CG, S and RHA waste products to be used as sustainable materials in pavement applications.

Study on Composite Materials by Replacement of Ceramic Waste Rice Husk Ash

Study on Composite Materials by Replacement of Ceramic Waste Rice Husk Ash

Influence of zinc oxide on the physical, structural and optical band gap of zinc silicate glass system from waste rice husk ash

Zinc silicate (ZnO-SiO2) glass was fabricated using melt-quench technique with compositions according to the empirical formula [(ZnO)x(WRHA)1-x] which x=0.50, 0.55, 0.57wt.%. These glass series acquire zinc oxide (ZnO) and white rice husk ash (WRHA) as silica source with two different melting temperatures of 1450°C and 1500°C. Temperature of 1450°C and 1500°C were chosen in this study because the lowest melting point of ZnO-SiO2 were at 1475°C and by choosing a temperature within the range of 1475°C a conclusive study on the best melting point using WRHA substituents can be done. Physical, structural and optical characteristics of fabricated glass samples were analyzed using Energy Dispersive X-ray Fluorescence (EDXRF), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV–vis (UV–vis). Optical band gap of the system was obtained by approaching the optical absorption techniques from the Mott-Davis methods. Results indicate that ZnO-SiO2 glass samples emerge in favors of direct and indirect forbidden transition and increase in ZnO causes a higher absorption thus resulting in lower band gap. Last but not least, in this study based on the increase of ZnO content, the glass samples which contains a higher amount of ZnO has a higher band gap as Zn2+ ions reacts as good network modifier in the glass structure and formed a better arrangement and structure compared to system which has less network modifier.

Effect of MnO2 doped on physical, structure and optical properties of zinc silicate glasses from waste rice husk ash

In this study, an investigation was conducted to explore and synthesize silicate (SiO2) glass from waste rice husk ash (RHA). MnO2 doped zinc silicate glasses with chemical formula [(ZnO)55+(WRHA)45]100-X[MnO2]X, (where X=0, 1, 3 and 5wt%) was prepared by conventional melt quenching technique. The glass samples were characterized using energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–Vis) spectroscopy. The results revealed that by increasing the concentration of MnO2, the color of glass samples changed from colorless to brown and the density of glass increased. XRD results showed that a broad halo peak which centered on the low angle (2θ=30°) indicated the amorphous nature of the glass. FTIR results showed basic structural units of Si-O-Si in non-bridging oxygen, Si-O and Mn-O in the glass network. FESEM result showed a decreasing porosity with an increasing MnO2 content, which was attributed to the Mn ions resort to occupy interstitial sites inside the pores of glass. Besides, the absorption intensity of glass increased and the band gap value decreased with increasing the MnO2 percentage. In this synthesized glass system of MnO2 doped zinc silicate glasses using RHA as a source of silica, the MnO2 affect most of the properties of the glass system under investigation.

Sustainable Construction—High Performance Concrete Containing Limestone Dust as Filler

Massive amounts of limestone waste are produced by the stone processing industry worldwide. Generally, it is believed that 60% to 70% of the stone is wasted in processing in the form of fragments, powder and slurry out of which around 30% is in the form of fine powder [1]. This waste has no beneficial usage and poses environmental hazards. Use of this waste product in the construction industry can largely reduce the amount of waste to be disposed off by the local municipalities in addition to reducing large burden on the environment. Some basic research on use of limestone dust as cement/ concrete filler has been carried out in the recent past but high strength/ high performance concretes have not been investigated yet [2] [3]. The concrete industry is among the largest consumer of raw materials worldwide and has been investigated for use of various types of waste materials like crushed brick, rice husk and straw ash as either aggregates for concrete or as partial cement substitutes. Use of limestone dust as filler material in concrete can consume a huge amount of this waste material which has to be disposed off otherwise, creating large burden on the environment. This experimental study aimed at evaluating the properties of high performance concretes made from Portland cement, natural aggregates and sand. Limestone dust was added by replacing sand in the percentages of 10% and 20%. Wide ranging investigations covering most aspects of mechanical behavior and permeability were carried out for various mixes for compressive strengths of 60 N/mm2, 80 N/mm2 and 100 N/mm2. Compressive strengths of concrete specimen with partial replacement of sand with 10% and 20% limestone dust as filler material for 60 N/mm2, 80N/mm2 and 100 N/mm2 were observed to be higher by about 4% to 12% than the control specimen. Flexural strengths were also observed to be higher by 12% - 13%. Higher elastic moduli and reduced permeability were observed along with better sulphate and acid resistance. Better strengths and improved durability of such high-performance concretes make it a more acceptable material for major construction projects.

A novel green ceramic hollow fiber membrane (CHFM) derived from rice husk ash as combined adsorbent-separator for efficient heavy metals removal

A new application of green ceramic hollow fiber membrane (CHFM) derived from rice husk ash (RHA) for efficient heavy metals removal has been developed. A common and advanced fabrication method, i.e. combined phase inversion and sintering technique was used to produce the membrane with high flux. Thereby, the membrane can effectively act, as both adsorbent and separator for heavy metals in single-step process with high separation efficiency up to 99% removal of zinc [Zn(II)], lead [Pb(II)] and nickel [Ni(II)]. The kinetic data of these heavy metals show the best fit for pseudo-first order for Ni (II) [R2 =0.981] and intraparticle diffusion kinetic model for Zn (II) [R2 =0.913] and Pb (II) [R2 =0.914]. Thus, this study convinced that the ceramic membrane from waste rice husk ash proved to be an attractive, effective and environmentally friendly both adsorbent and separator for heavy metals removal from aqueous solution.

Effects of Rice Husk Ash and Brick Waste on the Properties of Construction Bricks

This research reports the effects of rice husk ash and brick waste on the properties of construction brick. Clay is the raw material for producing brick. Both rice husk ash and brick waste are waste materials which can be added to clay to produce better quality brick with lower cost. Bricks of size 77mm x 38mm x 26mm were produced by stiff mud process. Three different sized rice husk ash and brick waste were used in different amounts (5%, 10%, 15%, and 20% by volume) as a partial replacement of clay while preparing the bricks. Some properties like drying and firing shrinkage, bulk density, and cold crushing strength were measured. There was decrease in drying and firing shrinkage, slight reduction in bulk density and decrease in cold crushing strength with increasing the rice husk ash and brick waste particle percentages.

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.

Comparing the Thermo-Physical Properties of Rice Husk and Rice Straw as Feedstock for Thermochemical Conversion and Characterization of their Waste Ashes from Combustion

The thermogravimetric characterization and gas emission properties during the pyrolysis of rice husk (RH) and rice straw (RS) were compared, and the properties of waste rice husk ash (RHA) and rice straw ash (RSA) from the combustion process were investigated. The results showed that the pyrolysis of RH and RS followed a four-step mechanism. Comparing the emission properties of small molecule bio-syngas in the pyrolysis of these two biomass wastes implied that RS was more suitable for use as feedstock for thermochemical conversion. Chemical and phase analysis results indicated that the RSA was rich in K, Ca, and P and had good potential for use as a soil amendment or as a material for silicate ceramics. The RHA was rich in SiO2 and could be an ideal silica source for silicon compound preparation or a pozzolan source for blended cement concrete production. Morphology analysis on the ash samples revealed that the high content of alkali metals may cause the higher agglomeration tendency of RSA with respect to RHA. The contrast in pore properties of biomass char wastes isolated from the ashes indicated that the char wastes recovered from RHA would be better used as a low-cost precursor in activated carbon production.

Laboratory investigation on the properties of asphalt concrete mixture with Rice Husk Ash as filler

Incorporating of waste and/or by-product materials in construction industry such as production of hot asphalt concrete mixtures provide valuable advantages in terms of environmental and economic points of view. Accordingly, in this laboratory study, it was investigated to use Rice Husk Ash (RHA) instead of conventional mineral filler in hot asphalt mixtures.The mechanical properties were assessed by conducting Marshall Stability and Indirect Tensile Strength tests. While moisture damage and long term aging were inspected by determining Index of Retained Strength (IRS) and Mean Marshall Stability Ratio (MMSR), respectively.The experimental results have shown a significant improvement in the mechanical properties and a substantial upgrading in durability of the produced mixtures i.e. asphalt concrete mixtures with RHA as a mineral filler (RHAAC) in comparison with the control mixtures which were prepared with OPC as a mineral filler (OPCAC).As a result of this study, RHA can be incorporated instead of conventional mineral filler in asphalt concrete mixtures particularly in areas where there is extensive RHA waste.

Modified Agro Waste Rice Husk Ash as Adsorbent for Natural Gas Storage System

Modified Agro Waste Rice Husk Ash as Adsorbent for Natural Gas Storage System

Static and Dynamic Mechanical Properties of Poly (vinyl chloride) and Waste Rice Husk Ash Composites Compatibilized with γ-aminopropyltrimethoxysilane

In this paper, γ-aminopropyltrimethoxysilane treated poly(vinyl chloride) (PVC)/rice husk ash (RHA) composites were successfully prepared by a reactive extrusion process. Experimental results revealed that both the tensile modulus and tensile strength increased at all silane coupling agent concentrations. The composites with 1 wt% silane exhibited the highest impact strength with 44 % increment. For the untreated composites, poor interfacial adhesion between PVC and RHA was clearly observed. Below the glass transition temperature (Tg), the silane induced higher storage modulus (E ′) but it seemed to be independent of E′ above Tg. Total water absorption at 90 days reduced by 38 % when the silane was added at 1 wt%, which confirmed that some voids were eliminated.

Concrete using agro-waste as fine aggregate for sustainable built environment – A review

Abstract High demand of natural resources due to rapid urbanization and the disposal problem of agricultural wastes in developed countries have created opportunities for use of agro-waste in the construction industry. Many agricultural waste materials are already used in concrete as replacement alternatives for cement, fine aggregate, coarse aggregate and reinforcing materials. This paper reviews some of the agro-waste materials, which are used as a partial replacement of fine aggregate in concrete. Different properties of fresh and hardened concrete, their durability and thermal conductivity when admixed with agro-wastes are reviewed. Agro-waste used in self-compacting concrete and mortar are also reviewed and their properties are compared. It has been seen that the agro-waste concrete containing groundnut shell, oyster shell, cork, rice husk ash and tobacco waste showed better workability than their counterparts did. Agro-waste concrete containing bagasse ash, sawdust ash and oyster shell achieved their required strength by 20% of replacement as fine aggregate, which were maximum among all agro-waste type concrete. Close relations were predicted among compressive strength, flexural strength, tensile strength, ultrasonic pulse velocity and elastic modulus of agro-waste concrete. Addition of bagasse ash as fine aggregate in mortar increased the resistance of chloride penetration whereas inclusion of cork in mortar showed better thermal resistance and improved cyclic performance. After the review, it is of considerable finding that more research is deserved on all fine aggregates replacing agro-waste materials, which can give more certainty on their utilization in concrete.