Papers by Keyword: Rice Husk

Abstract: Today, the solid waste problem is expanding at an alarming rate, and considering the scale of production and consumption, the textile industry contributes significantly to this waste. An indispensable component of fast fashion, polyamide-containing pantyhose are included in the disposable product group and cause irreversible loss of a very valuable raw material. The waste of this product group constitutes a hidden waste group that does not decompose in nature and has not yet been recycled. This study focuses on recycling polyamide-containing pantyhose waste and evaluating them in thermal insulation panel production. In this context, the process of opening the fibers of the pantyhose is carried out in a carding machine, and a hot press technique is utilized with the addition of low melting temperature polypropylene fibers as a binder, for panel production. Rice husk, which is a commonly known agricultural waste, is also introduced into the panels in different forms (granule and powder) for better air encapsulation. The effect of ply number (two and four) and the form of rice husk added as an additive on thermal and air permeability properties is examined within the framework of a full factorial experimental design plan. The findings obtained reveal that the variables affect both thermal insulation and air permeability properties both individually and in binary interactions. The lowest thermal insulation coefficient is obtained in the two plied, granule form rice husk added sample group (0.02117 W/mK), which also has the highest air permeability values (442.57 l/m²/s) and the results are found to be competitive with commercial products. This suggests that it is possible to use this waste group in sustainable panels for construction, and the findings reveal that it may create value in terms of both solid waste management and exploring new resources for polyamide-based fibrous products.

Abstract: This research aims to study the properties of polishing pads made from polyurethane mixed with rice husk fiber for use in chemical mechanical polishing (CMP) of sapphire. After cleaning and sizing, the rice husk fiber was modified using hydrochloric acid (HCl). Then, both unmodified and modified rice husk fibers were mixed with polyurethane at ratios of 7.5, 10, and 12.5 phr to form polishing pads. The hardness and polishing performance of these pads in sapphire CMP were then tested. The experimental results showed that polishing pads from rice husk fiber could be successfully formed and remained stable. The natural fibers were evenly distributed across the contact surface of the pads. The hardness of polishing pads from rice husk fiber was smaller than conventional polishing pad (SUBA800) in range of 40.5–47.5%. Polishing results revealed that pads made from polyurethane mixed with unmodified and modified rice husk fiber achieved the highest material removal rates (MRR) of 94.2% and 64.7%, respectively, compared to the conventional pad. These results indicate that both types of fibers able to be used as a material for manufacturing polishing pads for adding value and reducing the waste from the agricultural.

Abstract: This study investigated the potential of acid-pretreated rice husk ash (RHA) sourced alkaline earth metal silicates for lauric acid (LA) adsorption. The synthesized materials were characterized using BET, FTIR, XRD, EDS, and SEM analyses, demonstrating that metal cation size had a notable effect on surface area, pore structure, crystallinity, and particle aggregation. Magnesium silicate (MS-1.0), with its smaller atomic radius, exhibited the highest surface area and the most porous structure among the samples. Calcium silicate (CS-1.0) displayed a moderate surface area with a mesoporous structure, while strontium silicate (SS-1.0), having the largest atomic radius, exhibited the lowest surface area, a predominantly macroporous structure and the highest degree of particle aggregation. The synthesized alkaline earth metal silicates were tested for LA adsorption performance and compared using the analytical hierarchy process (AHP). CS-1.0 demonstrated the highest LA removal efficiency (59.94% ± 11.24%) and adsorption capacity (8.68 ± 1.60 mmol/g), while MS-1.0 had the lowest removal efficiency (17.64 ± 3.28%) and adsorption capacity (2.60 ± 0.50 mmol/g). Interestingly, the production yield increased from MS-1.0 to CS-1.0 and SS-1.0. Through the AHP method, CS-1.0 was identified as the best-performing adsorbent in this study, considering both adsorption efficiency and production yield with the highest priority value of 0.9603.

Abstract: The role of plastic packaging in protecting food is considerable, but issues such as non-biodegradable properties, recycling problems, and leaching of harmful chemicals on food and soil create serious concerns for human health and the environment. Global packaging protocols and awareness about plastic packaging also make it necessary to develop new packaging materials that focus on the environment, food quality and safety. Therefore, urgent attention is needed for alternative biodegradable food packaging materials, so this study aims to fabricate biofoam from rice husk waste using starch adhesive. The main material used was rice husk with size variations of 40, 60 and 80 mesh. The weight ratio between husk and adhesive is 1:2. All biofoam products were analyzed for physical properties (water absorption), heat resistance and biodegradability. Based on the research that has been done, biofoam of rice husk waste with starch adhesive has the potential to be used as a substitute for synthetic polymers with the sticking method with a compressive strength of 100 kg at a temperature of 102°C. The best biofoam is in the variation of 80 mesh particles with added weight after testing water absorption of 15%, heat resistance with added weight of 1%.

Abstract: High nickel content in nickel manganese cobalt (NMC811, LiNi_0.8Mn_0.1Co_0.1O₂) resulted in high capacity but low structural stability. Surface modification of NMC811 via silica (SiO₂) coating is known to counter this problem, leading to better electrochemical performance. In this work, silica was synthesized from rice husk through sol-gel method with alkaline extraction followed by acidification process. The resulting silica was coated onto commercially available NMC811 to modify its surface via solid-state reaction method. The characterization results showed that the silica coated NMC811 demonstrated a higher conductivity and lithium diffusion coefficient of 2.85 x 10^-5 S/cm and 2.52 x 10^-14 cm²/s, respectively, compared to that of bare NMC811 (8.17 x 10^-6 S/cm and 1.75 x 10^-15 cm²/s, respectively). This result confirms that the silica derived from rice husk can be used as a potential low-cost material to modify the surface and thus to increase the electrochemical performance of commercial NMC811.

Abstract: Vietnam is one of the largest rice producers in Southeast Asia, generating substantial quantities of rice husk as a by-product of rice milling. Currently, rice husk is predominantly disposed of as agricultural waste. This study investigates the utilization of rice husk to synthesize silicon carbide (SiC) and crystal silica (SiO₂). The device for the experiment was built by the authors with simple accessories. SiC and crystal SiO₂ from rice husk were synthesized successfully at low temperatures compared to a chemical reaction of silica reduced by carbon. The research outlines the production conditions for achieving a little SiC from recycled rice husk and explores potential development pathways for applying this technology in structural and material manufacturing industries. The characterization of the synthesized SiC was measured using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Abstract: Graphene is the only carbon allotrope in which every carbon atom is densely connected to its neighbours by an electronic cloud, raising various quantum physics concerns. In recent years, many researchers have focused their efforts on developing more efficient methods for synthesizing graphene. However, only few methods can simultaneously synthesize mass-produced, cost-effective, and high-quality graphene. In this study, we are emphasizing the use of rice husk (RH) as the raw material to prepare graphene by using two-step pyrolysis. Zinc chloride (ZnCl₂) is an example of an activating agent that is used to improve the efficiency of the synthesis of graphene from rice husk. After conducting pre-treatment of rice husk, the first stage of pyrolysis was conducted by varying the ratio of ZnCl₂ to the RH (1:1, 2:1, 3:1) at a carbonization temperature of 500 °C for 1 hour, followed by second-stage pyrolysis under 900 °C for 90 minutes and post-treatment. The findings of the characterizations, which included yield analysis, scanning electron microscopy (SEM) and Raman spectroscopy, Brunauer-Emmett-Teller (BET), and CO₂ adsorption analysis, revealed the impacts of the ZnCl₂ as activating agent, on the yield and graphitic structure of graphene and the potential application of graphene as a CO₂ adsorbent. Raman spectroscopy confirmed the graphitic properties of graphene synthesized in all samples with RH1:1 produced the best quality of graphene due to its low I_D/I_G intensity ratio (0.8913) and the highest I_2D/I_G intensity at 0.24. In addition, RH1:1 exhibited the highest surface area, whereby the highest total pore and micropore volume is contributing to the highest CO₂ adsorption capacity of 8.73 mmol/g. This proves that the activating agent ratio has significant effects on the graphene quality produced from rice husk as well as the adsorption performance.

Abstract: The mesoporous silica nanoparticle (MSN) is a material with easily controllable pore size and excellent surface area to develop into a corrosion inhibitor nanocarrier, a protective coating specially produced by a nanocomposite layer to keep or release anticorrosive active compounds. Nonetheless, the MSN is not weakness-free, which cannot impede corrosion propagation actively. Special treatment for overcoming is developing the benzotriazole-silver (BTA-Ag)-based capping system, with advantages that can exploit the double anticorrosive mechanism by adjusting anticorrosive active compound release while capturing chloride ions, leading to active self-healing. Therefore, this work identifies the effect of developing a capping system based on BTA-Ag on the porosity properties of MSN as an initial step in preparing corrosion inhibitor nanocarrier. Rice husks were chosen as eco-friendly materials to replace commercial precursors because of their abundance, the same orthosilicate structure, and the high purity of silica. With excellent levels of safety and uniformity, this work uses the sol-gel method to reduce the synthesis energy or cost. The outcome indicates that the porosity characteristics of these nanoparticles are significantly impacted by the BTA-Ag-based capping method. The pore size shrank to 2.5 nm from 2.6 nm. Additionally, the surface area decreased dramatically from 653.149 to 41.725 m²/g. Moreover, the pore volume dropped from 0.9 to 0.1 cm³/g. However, it had a comparable morphology, varied in size, and a specific aggregation level, indicating the presence of densely packed rod-like micelles during the MSN synthesis. The sample was confirmed to be porous since the isotherm graph was of type IV. It was highly reactive due to silanol and siloxane groups, signaling bonds with the silica matrix being the main component.

Abstract: The characterisation and insulating efficiencies of sawdust and rice husk in glass shavings reinforced termite clay-based (GSRTC) composite has been compared. Termite clay was unearthed from the Federal University of Technology, Akure (FUTA) campus in Ondo State. It was processed to obtain 150 μm undersize. Glass shavings were processed to obtain 106 μm undersize. The glass shavings were then mixed with the termite clay in a constant weight proportion of 10%. Sawdust and rice husk were processed to obtain 150 μm undersize. The prepared blended GSRTC powder was mixed with the sawdust, and the rice husk in 2, 4, 6, 8, and 10 wt.%. The resulting mixtures were compacted into cylindrical-shaped samples. The samples were dried and fired in a furnace at 1000°C for 2 hours. The chemical composition of GSRTC composite constituents was studied prior to the production of the composite. The control sample with only 10 wt.% of glass shaving possessed the highest: compressive strength; linear and volumetric shrinkage; bulk density; and thermal conductivity, while the sample with 10 wt.% of sawdust in GSRTC possessed the lowest: compressive strength (1.62 MPa); linear and volume shrinkage; bulk density (0.68 g/cm³); thermal conductivity (0.23 W/m-K).. Conclusively, the additive proportion and type affect composites' physical properties. An increase in additive proportion is accompanied by an increase in porosity, a reduction in porosity and bulk density. The compressive strength and thermal conductivity decreased with increasing additive content. GSRTC composites with sawdust additive possessed better insulating performance. However, GSRTC composite with rice husk additive displayed higher compressive strength.

Abstract: Anaerobic digestion or anaerobic digestion is a biological process of degradation of organic matter in an anaerobic environment. It involves the degradation and stabilization of complex organic matter by a consortium of micro-organisms leading to methane-rich biogas that can be used as an alternative energy to fossil fuels. In addition, the use of biogas allows for the preservation of the environment and the sustainable development of rural areas and landlocked regions, as well as the diversification of energy resources, but also contributes to the development of agriculture through the production of organic fertilizer. In 2018, Senegal was ranked as the 15th world exporter of cashew nuts with a production of around 18,000 tons per year according to a study by PADEC (Support Program for the Development of Casamance). Four regions mainly invest in it: Kolda, Ziguinchor, Sédhiou, and Fatick. However, in the natural region of Casamance ( Kolda, Ziguinchor, and Sédhiou), each year, after the cashew nut campaign, more than 342,000 tons of cashew apples, pressed or not, are rejected without any recovery, thus degrading in the environment. In addition, rice is traditionally grown in Casamance and in some Diola circles, it had become one of the criteria of wealth, which explains why it occupied most of the cultivated areas and each year thousands of tons of rice husk are burned for elimination/reduction without any recovery. These immense annual productions of waste, without any recovery, in a context dominated by a deficit in cooking and lighting energy constitutes a form of energy resilience and motivates us to study the co-digestion of the rice husk (with a report of C/N equal to 101.317) on cashew apple pulp (having a C/N ratio of 23.201 ). The study of the co-digestion of rice husk and apple pulp at the laboratory scale with the inoculum reveals, that the co-digestion with pH correction contains 39.40% methane and 51.50% carbon dioxide after 49 days of production and 64.04% methane (CH₄) and 25.86% carbon dioxide (CO₂) on the 96th day. For co-digestion without adjustment, production stopped on the 49th day with a production of 23.68% methane and 45.65% carbon dioxide.