Rice Husk Ash Research Articles

Exploring sustainable solutions for soil stabilization through explainable Gaussian process-assisted multi-objective optimization

The adoption of sustainable solutions in soil stabilization has piqued the interest of the scientific community due to the potential reduction in carbon footprint. In this regard, the research community has started looking for the alternate sustainable solutions to limit the quantity of conventionally used ecologically unfriendly soil stabilizers like lime and cement by utilizing the agricultural and industrial by-products. The production of conventional soil stabilizers (lime and cement) is extremely energy-intensive and contributes tons of greenhouse gases to the atmosphere. In general, evaluating suitability of these additives requires in-lab investigation of soil samples with varying additive concentrations and curing periods, making this approach both resource and time-intensive. Hence, this article proposes a computational framework for accelerated characterization of soil-stabilization by using the coupled experimental-Gaussian process (GP) based machine learning (ML) model. The dataset utilized for constructing the GP models consists of input features such as the stabilizer content (lime and rice husk ash (RHA)), coir fiber content, and curing period (measured in days). The target responses are the strength measures of the stabilized soil, such as unconfined compressive strength (UCS), split tensile strength (STS), and California bearing ratio (CBR). The proposed computational framework is deployed to perform multi-objective genetic algorithm (MOGA)-based optimization to achieve maximum engineering performance from stabilized soil. The presented study demonstrated that with the optimal dosage of rice husk ash (agricultural by-product), and cashew nut shell liquid (CNSL) treated coir fiber, the requirement for lime dosage may be significantly reduced while maintaining the engineering performance of the soil. The presented computational framework can be extended to any construction practices for ensuring the strategic selection of the control variables for optimizing the desired performance.

Insight into adsorption-desorption of methylene blue in water using zeolite NaY: Kinetic, isotherm and thermodynamic approaches

It is critical to find an efficient method to separate methylene blue (MB) in wastewater before discharging them into environment. Adsorption using zeolites is the most commonly used one. To determine adsorption mechanism providing useful data to enhance adsorption capacity and practicability of scale-up, kinetic, isotherm and thermodynamic adsorption were evaluated and discussed intensely. Zeolite NaY was synthesized from rice husk ash with a one-stage process. Effects of pH, contact time, initial concentration, adsorbent dose, temperature, solvents and recyclic stability on MB adsorption and desorption were investigated in detail via alternating variable method. Optimal conditions for adsorption were at pH 8, 1 h, 50 mgMB/L, 303K. Adsorption kinetics and isotherms showed that the process fitted to pseudo-second-order, Freundlich and Temkin isotherm, indicating a spontaneous, exothermic and physical adsorption process with multilayer adsorption. Desorption process showed that EtOH:H2O (1:1) solvent at 323K was optimal for releasing MB and its thermodynamic studies revealed that this process was favorable with rising temperature. The maximum adsorption capacity was calculated as 49 mg/g and the adsorbent could maintain its adsorption performance after six cycles. Generally, this study provided a comprehensive approach of an efficient, cost-effective, and recyclable NaY for MB removal from water.

Consistency and compatibility study on clayey soil blended with rice husk ash and fly ash

Consistency and compatibility study on clayey soil blended with rice husk ash and fly ash

Effect of Rice Husk Ash (RHA) and slake-lime as partial replacement of cement in the production of concrete

This study examines the utilization of rice husk ash (RHA) and slaked lime as substitutes for a portion of the cement in manufacturing concrete. The RHA was acquired from a nearby source, subjected to calcination at temperatures ranging from 500 to 700 °C, and then passed through a sieve to obtain particles with a size of 150 microns. Concrete mixes were made using Ordinary Portland cement (OPC), fine and coarse aggregates, and water, with different amounts of RHA and slaked lime. The concrete mix design adhered to established standards, with a mix ratio of 1:1.5:3 (cement: fine aggregate: coarse aggregate). The experiment was designed using response surface methods, with RHA, slaked lime, and cement as factors, each having five levels. Concrete cubes were formed using 100 mm steel moulds and then submerged in water to assess their workability. The compressive strength was measured using universal testing equipment after 7, 28, and 90 days of cure. The flexural strength of concrete beams was assessed after 7 and 28 days. Samples were subjected to scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) examination after 28 days. The compressive and flexural strengths increased as the curing period progressed, with the 10% RHA substitution showing the maximum strength. The SEM analysis showed that RHA10 exhibited the maximum concentration of silicon, which corresponds to the recommended 10% replacement level of OPC and meets the concrete specifications specified by ASTM M20 grade. Utilising RHA decreases expenses and minimises the amount of concrete that is discarded. The most effective replacement for OPC was 10% RHA, which produced long-lasting and strong concrete.

Synthesis of geopolymer mortar from biomass ashes and forecasting its compressive strength behaviour

The global warming dilemma raised an exigency toward sustainability in the construction industry and compelled scientists to hunt for alternative binders in construction materials. The, geopolymerization as a spectacular technology has arisen as a looming solution to this dilemma. This work assesses the features of geopolymer mortar developed with both industrial and agricultural wastes at ambient temperature curing. The geopolymer mix proportion was evolved in this study using main precursor material as fly ash, ground granulated blast furnace slag (GGBFS), sugarcane bagasse ash (SCBA) or rice husk ash (RHA). Workability and mechanical properties, including compressive strength, flexural strength, and split tensile strength of different mortar mixes with various percentages of RHA and SCBA for 365 days, were evaluated. Geopolymer mortar with 10 % SCBA and 5 % RHA achieved improvements of 25 % and 13.91 % in compressive strength, 10.6 % and 3.5 % in flexural strength, and 35 % and 16.8 % in split tensile strength, respectively. Good geopolymer gel formation is clearly evident from the SEM images of SCBA mortar. The main polymeric bonds Si–O–Al and Si-O-Si are also identified using FTIR. To assess the efficacious use of biomass ashes, resistance to chemical attack using H2SO4, HCl, Na2SiO3, and NaCl solutions for 365 days was studied. It was revealed that SCBA incorporated geopolymer mortar specimens achieved good resistance compared with RHA geopolymer mortar. The relation between the ambient temperature cured geopolymer specimen compressive strength at 28 days and 365 days chemical solution curried geopolymer specimen compressive strength find out using python and obtained R2 values more than 95 %. Also, this research proposed various machine learning techniques such as long short-term memory, support vector regression, random forest regression, XGBOOST, and AdaBOOST algorithms for the prediction of compressive strength of geopolymer using 724 mixture proportions with diverse curing temperatures and varying ages. The XGBOOST algorithm achieved the highest R² value of 0.92, demonstrating its effectiveness for the strength prediction.

Fabrication and Characterization of Rice Husk Ash Reinforced Aluminium Matrix Composite

Fabrication and Characterization of Rice Husk Ash Reinforced Aluminium Matrix Composite

Mechanical properties of rice husk ash and glass powder concrete: Experimental and mesoscopic studies

Using glass powder and rice husk ash as supplementary cementitious materials (SCM) can effectively reduce cement usage, protect the environment, and promote waste recycling. In this study, ordinary concrete, glass powder concrete, and glass powder rice husk ash concrete were studied through a series of experiments, including tests for slump and water absorption, uniaxial compression, variable angle shear, cyclic compression, and numerical simulation. The following results were identified. Glass powder increases the slump of concrete and reduces its water absorption, whereas the opposite is the case with the addition of rice husk ash. The uniaxial compressive strength of glass powder concrete is higher than that of ordinary concrete at 28 days of curing. Glass powder concrete has the maximum bearing capacity, in terms of the shear test. The minimum damage index is shown under cyclic compression. When the rice husk ash content is 15 %, the combination with glass powder has the strongest pozzolanic effect, while the replacement rates of 30 % and 45 % are not suitable for pozzolanic materials. The dissipation energy conversion rate of the sample containing rice husk ash is always greater than the elastic strain energy conversion rate. In addition, the samples containing rice husk ash showed ductile failure and reduced cracks during compression. This study can provide new insights into the combination of glass powder and rice husk ash as SCM.

Upcycling rice husk ash and coal-fired fly ash as si/al sources into hierarchical ZSM-5 for efficient mercury capture from industrial flue gas

Limiting gaseous Hg0 emission is pressing due to the high toxicity in the ecosystem. Zeolites can be regarded as a promising alternative to carbon-based Hg0 adsorbents. However, the mass transfer limitations of conventional singe-sized zeolites constrain the industrial application of zeolites. This study explores the synthesis of hierarchical ZSM-5 zeolites using rice husk ash (RHA) and coal-fired fly ash (FA) as sustainable sources of silicon and aluminum, aimed at enhancing Hg0 removal from industrial flue gases. By adopting a one-step hydrothermal method, we introduced hierarchical porosity into the ZSM-5 framework, enhancing mass transfer and adsorption efficiencies. Iron (III) chloride (FeCl3) was utilized as an active species for modifying the hierarchical ZSM-5, significantly boosting its Hg0 adsorption capabilities. Fe/6RF-hZ demonstrating more than 92% mercury removal efficiency in 60 min under mixed flue gas condition. The structural and chemical attributes of the synthesized ZSM-5 were detailedly characterized, revealing notable differences in surface chemistry and porosity that correlate with varying calcination temperatures of RHA. TEA analysis reveals that hierarchical ZSM-5 zeolites outperform traditional sorbents in demercuration (DeHg) applications, with exceptional DeHg efficiency, energy efficiency (12 kWh), synthesis cost (860 $/ton), and carbon content (non-carbon). This study not only sheds light on the upcycling of solid wastes in synthesizing novel adsorbents but also contributes to the broader application of zeolitic materials in environmental remediation.

Optimization of HVOF Spray Parameters for WC-Co-Cr Coatings on AMMC (Al-RHA) for Pump Impeller Protection

Present study investigates the enhancement of pump impeller materials using aluminium matrix composites (AMCs), specifically focusing on Al 7075 Alloy strengthened with rice husk ash (RHA) for enhanced durability and resistance to corrosion. It employs Thermal spraying using high-velocity oxygen-fuel (HVOF) to apply WC-Co-Cr powder, emphasizing low porosity, high adherence, and superior wear and corrosion resistance. By optimizing HVOF spray parameters using Taguchi L25 Orthogonal array, the research aims to minimize porosity and maximize hardness, addressing challenges in material dispersion, sustainability, and process control. The objective is to develop predictive models for the microhardness and porosity characteristics of WC–10Co–4Cr coating powder utilized through HVOF on AMMC substrates. AMMC substrates. Spray distance, carrier gas flow rate, powder feed rate, oxygen flow rate, and LPG flow rate are examined, with spray distance exerting the most significant influence on porosity, followed by powder feed rate and other parameters. This study contributes to improving coating characteristics crucial for industrial applications.

Towards a sustainable rice husk ash-derived solid-phase extraction: Perfluoroalkyl substances as probe contaminants of waters

Rice husk ash is an important waste of agricultural industry that, within the framework of the circular economy, has been easily converted into a sustainable sorbent material. This was tested in this work for the pre-concentration of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), representative perfluoroalkyl substances as probe environmental pollutants of waters, with HPLC-MS/MS quantification. The preparation involves a rapid microwave-assisted oxidation followed by a hydrothermal treatment, which was studied using a 22 design of experiments. The final material was thoroughly characterized and tested for its affinity to the target analytes by solid-phase extraction in environmental waters and wastewaters. Recoveries in the range 67–113 % (RSD < 11 %, n=3) were achieved at environmentally relevant concentrations (10, 50, and 100 ng L-1) and the sorbent was reusable for at least ten consecutive extractions. Good linearity (R2 = 0.9997) was observed, with a method quantification limit in the water sample of 10 ng L-1 that allows the analysis of PFOA and PFOS below the established limits. The method was evaluated for greenness using AGREEprep and SPMS metrics, and it was then applied to the analysis of actual water samples from Northern Italy.

Sustainable ground improvement of soft clay using eggshell lime and rice husk ash

Stabilization of clay using lime or cement is conventionally accepted practice. Although it is effective, they impose several implications on the environment. Hence, it is high time that an alternate sustainable binder needs to be investigated. Eggshell, a waste from food industry, is an alternate source for calcite and can be considered to produce eggshell lime (EL). Also, rice husk ash (RHA), an agricultural waste product, is a silica rich source which is a pozzolanic material. In the current study, the efficiency of both the materials in stabilizing the soft soil is investigated and the results suggests that the plasticity and the strength characteristics of soft clay can be significantly improved by the addition of EL. After adding optimum concentration of 3 % EL, the liquid limit decreased from 74 % to 53 %, plastic limit increased from 27 % to 46 % and shrinkage limit increased from 8 % to 44 %. On increasing the EL content, the swelling got reduced from 88 % of virgin clay to 17 % in case of 3 % EL and finally to zero with 5 % of EL. Also, the addition of combination of EL and RHA to the soft clay has improved the strength characteristics significantly. As the curing days increased, slight variation was only seen in the plasticity characteristics which may be due to rapidity of cation exchange. But strength characteristics increased suggesting the occurrence of pozzolanic reactions and formation of gel. The 28th day strength of the clay treated with 3 % EL increased to as high as 757 kPa. The strength characteristics showed that as we increase the percentages of EL and RHA combination, the strength would increase tremendously much better than the treatment with eggshell lime alone. This is because of the supply of CaO and SiO2 sources. For 5 % of EL and 15 % of RHA, the 1 day curing strength was near to 500 kPa. With less concentration of eggshell lime and RHA, the treated soil was appearing to be more porous in SEM while when the binder concentration was increased, the pores were filled and presence of C-S-H gel was also detected. XRD test results also showed the presence of C-S-H gel.

Investigating the Strength Enhancement in Cement Concrete through Experimental Study on the Influence of Rice Husk Ash

Investigating the Strength Enhancement in Cement Concrete through Experimental Study on the Influence of Rice Husk Ash

Enhancement effect of calcium carbide residue and rice husk ash on soft soil: Small-strain property and micro mechanism

The resource utilization of calcium carbide residue (CCR) and rice husk ash (RHA) is helpful to save resources and alleviate environmental pollution. In this research, CCR and RHA were used to modify soft clay, and the resonant column test was conducted to explore its small-strain dynamic characteristics. The micro-mechanism of CCR-RHA modified soft clay (CRSC) was investigated by using scanning electron microscopy, X-ray diffraction and mercury intrusion tests. The findings demonstrated that the dynamic shear modulus of the CRSC increased with the increase of RHA content and confining pressure, but decreased with the increase of shear strain. In contrast, the damping ratio presents the opposite change law. The Hardin-Drnevich (H-D) model was used to fit the dynamic shear modulus/maximum dynamic shear modulus (G/Gmax)-shear strain γ and the damping ratio D-shear strain γ. As confining pressure increased, Gmax increased but Dmax dropped in CRSC specimens with the same RHA content. The changes of the fitted G/Gmax-γ curve could be divided into progressively decrease stage and rapid decrease stage, while the changes of the fitted D-γ curve could be separated into linear stage and slow stage, with the same turning point γ = 10−4. Microscopic tests revealed that the incorporation of CCR and RHA helped to promote the hydration reaction, and the generated hydration products such as calcium silicate hydrate were able to enhance the integrity and compactness of the CRSC. The results of this research putfward solid foundation for the application of CCR-RHA in the modification of soft soil.

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 the 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 crystals 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 a smaller crystallite size (14.8 nm) compared to the PS-7 obtained from C72H, which shown the lower surface area (131.5 m2/g) with a larger crystallite size (25.6 nm). Solid-state NMR and NH3-TPD analysis reveals that PS-5 catalyst possessing higher acidity compare to both PS and PS-7. The activity studies confirms that the PS-5 catalyst exhibited superior catalytic activity (>98%) compared to PS (conventional) and PS-7 catalysts, making it a potential candidate for continuous production of aromatic ketones. acylation reactions.

Development of lightweight structural concrete with artificial aggregate manufactured from local clay and solid waste materials

The partial replacement of conventional natural coarse aggregate (NCA) with artificial light weight aggregate (LWA) manufactured from local clay and solid waste to develop a lightweight aggregate concrete (LWAC) for the structural use was studied in this paper. Red clay and Savar clay were used individually with solid wastes like rice husk ash (RHA) and waste glass to produce LWA. The suitability of raw materials and LWA was evaluated by investigating various properties. The mechanical, thermal and durability properties of manufactured LWAC were explored. The results of physical, chemical, thermal and geotechnical properties revealed that Red clay is better than Savar clay for the preparation of LWA. All the physical and mechanical properties of LWA prepared from Red clay are suitable for the preparation of LWAC compared to Savar clay. The test results demonstrated that the concrete manufactured by replacing 30 % of NCA with LWA produced a concrete of lightweight properties. The compressive strength of LWAC for 7 and 28 days was observed as 28 and 48 MPa, respectively. The results of modulus of elasticity, splitting tensile strength, flexural deformation, and creep test of LWAC revealed that these mechanical properties meet the requirements for the structural concrete. The RCP test proves that chlorine permeability of LWAC is comparable with NCA. It was observed that the superior performance of LWAC can be achieved only when the optimized mix designed is followed strictly. The suitability of the replacement of natural aggregate by LWA may be helpful for Bangladesh due to the scarcity of natural coarse aggregate and reusability of solid waste materials.

Optimizing mechanical performance and flow characteristics of alkaline fly ash/rice husk ash composite backfill: Insights from multi-factor analysis and engineering optimization

In order to effectively dispose of agricultural waste rice husk ash and improve the mechanical properties of backfill, the properties of fly ash/rice husk ash composite backfill material were studied in the laboratory. The effects of fly ash, rice husk ash, straw fiber and NaOH content on the properties of composite backfilling materials were studied, and the ratio parameters of composite backfilling materials were optimized based on engineering examples. Our findings reveal that fly ash content significantly impacts slump, with its addition enhancing the flow performance of composite backfilling materials. Conversely, straw fiber, rice husk ash, and NaOH content were found to have non-significant effects on slump. We observed that with the increase of fly ash content from 5 % to 20 %, the compressive strength of the backfill firstly increases and then decreases, and the optimal content range is about 10 %. Moreover, increased rice husk ash and NaOH content effectively enhance the UCS. However, higher fly ash and straw fiber content were found to impede the strengthening effect of NaOH on UCS. Nevertheless, higher NaOH content was observed to augment the strengthening effect of rice husk ash content. Furthermore, when the content of fly ash and rice husk ash is 5∼10 % and 3–12 % respectively, rice husk ash and fly ash effectively reduce the size range of internal void structures, enhancing the microstructure density and mechanical properties of the composite backfilling material. Based on engineering example, we determined the optimal ratio parameters of the composite backfilling material to be: 20 % fly ash content, 9 % rice husk ash content, 0.4 % straw fiber content, and 2.5 % NaOH content. This study is helpful to promote the application of waste rice husk ash and straw fiber in mine filling, and provides theoretical guidance for the parameter design of backfilling materials.

Load bearing geopolymer from agro-waste and its energy-environmental- economic (E3) performance: Application through building information modeling

Agro-waste geopolymers are being significantly researched as sustainable substitutes to traditional construction materials for structural performance. However, a thorough assessment of their energy, environment, and economic (E3) performance is still questioned to facilitate in-situ building applications. This study first opts for a novel method of pressure catalysis for rice husk ash (RHA)-based geopolymers to enhance physico-mechanical performance with a low alkali activator dose. Afterward, the thermal conductivity of the optimized specimen was evaluated experimentally. Then, to assess its practical application, an E3 performance investigation was conducted on masonry brick/blocks as a pioneering approach for geopolymers. Distinct wall scenarios were simulated using Building Information Modeling (BIM) in a digital residential building. The experimental results showed that geopolymers with 50 % RHA, catalyzed under 20 MPa pressure, achieved 26.8 MPa compressive strength, lower density (1510 kg/m3), reduced water absorption (6.8 %), and 0.552 W/(m·K) thermal conductivity, outperforming traditional fired-clay brick and concrete block. The BIM analysis revealed that walls with RHA material had 53 % lower energy consumption and 30 − 41 % lesser CO2 emissions, respectively. Despite the higher cost, the RHA block has advantages as a masonry unit due to a high economic index. The significant energy and environmental gains suggest the potential for optimizing the production process of RHA-based geopolymer to enhance cost-effectiveness and amplify benefits.

Influence of rice husk ash inclusion on electrical characteristics of dry cement mortar

Influence of rice husk ash inclusion on electrical characteristics of dry cement mortar

Utilization of waste materials for soil stabilization: A comprehensive review

Soil stabilization, is a crucial aspect of civil engineering, entails the modification of soil properties to meet specific engineering standards. This is conventionally achieved through compaction and the incorporation of stabilizing agents or admixtures. Lime and cement have been predominant choices for soil stabilization, demonstrating effectiveness in altering soil properties. However, recent research has unveiled a notable shift towards the utilization of waste materials, such as fly ash and rice husk ash, for soil stabilization purposes. These waste materials, when used alone or in conjunction with lime or cement, have shown promise in achieving the desired engineering outcomes. The literature review conducted for this purpose delves into the existing body of knowledge on the utilization of waste materials in soil stabilization. Emphasizing their potential benefits, the review explores the effectiveness of these materials in altering soil properties and meeting engineering specifications. By investigating alternative stabilizing agents derived from waste materials, this research contributes to a sustainable approach in soil engineering practices. The findings presented in this paper shed light on the potential of waste materials for soil stabilization, offering a viable solution for waste disposal while addressing environmental concerns associated with traditional stabilizers.

Comparative analysis of the strength of concrete made from selected admixtures for use in rigid pavements

This study evaluates the influence of sawdust ash, glass powder and rice husk ash as admixtures for partially replacing fine aggregate in concrete for rigid pavement applications. Compressive strength tests were conducted at 5%, 10%, 15%, and 20% replacement levels. Rice husk ash achieved the highest compressive strength of 10.40 N/mm2 at 10% replacement after 28 days, closest to the control. However, sawdust ash and glass powder exhibited reduced strengths as replacement levels increased. The maximum compressive strength obtained did not meet the required target for rigid pavement applications.