Husk Biochar Research Articles

Experimental studies, characterization, and optimization of organic nonconsumable biomass wastes for utilization in energy storage applications

ABSTRACT In this work, two organic nonconsumable biomass municipal wastes, coconut peduncle (CP) and areca nut husk (ANH), were selected as per novelty, and the results were experimentally investigated and optimized for better suitability as per energy storage applications. Fourier transform infrared spectroscopy (FTIR) analysis of both the biomasses shows the presence of oxygen functional groups and aromatic compounds, such as lignin which are the important parameters for energy storage. CP contains more lignin content than ANH by 2.21% as investigated by the National Renewable Energy Laboratory (NREL) protocol. Proximate analysis of the two biomasses revealed that CP has more volatile matter and a lower ash content than does ANH, indicating better pore development for energy storage. Thermogravimetric/differential thermogravimetric (TG-DTG) curve reveals that both the biomasses are thermally stable nearly at 500°C above which slow pyrolysis can be performed. Two-step KOH activation improved the yield of the biochar at 1:4 (w/v) biochar to KOH ratio through direct impregnation. The adsorption−desorption isotherm shows that activated coconut peduncle biochar at 1:4 (ACPB4) has a better surface area of 494.076 m2/g and microporosity than activated areca nut husk biochar at 1:4 (AANHB4) making CP a suitable porous material for energy storage.

Microwave-assisted magnetic biochar for removal of hexavalent chromium from aqueous solution

ABSTRACT In this study, biochars were prepared by pyrolysis of tea waste and rice husk and hexavalent chromium (Cr(VI) sorption was obtained after post-modification of biochars with magnetic iron nano/micro-particles. The maximum sorption of Cr(VI) by magnetic tea waste biochar (MTWB) was 99.9% followed by 97.36% for magnetic rice husk biochar (MTRHB) at pH 5.2. Among studied competing ions, sulfate ions (SO4 2-) considerably reduced the sorption of Cr(VI) up to ~66.5% for both biochars. The surface functional groups such as – OH, C-H, Fe-O and porous biochars structure loaded with iron nanoparticles helped in Cr(VI) adsorption by ion exchange and electrostatic interactions as indicated by FTIR, XPS and SEM-EDS data. Both Cr(III) and Cr(VI) species were observed on biochars surface confirming the Cr(VI) removal process by reduction and direct adsorption of Cr(VI) ions. Hence, this study provides an excellent option for the application of magnetic biochars to treat Cr(VI) containing wastewater.

Innovative Microbial Immobilization Strategy for Di-n-Butyl Phthalate Biodegradation Using Biochar-Calcium Alginate-Waterborne Polyurethane Composites.

Di-n-butyl phthalate (DBP) is a prevalent phthalate ester widely used as a plasticizer, leading to its widespread presence in various environmental matrices. This study presents an innovative microbial immobilization strategy utilizing biochar, calcium alginate (alginate-Ca, (C12H14CaO12)n), and waterborne polyurethane (WPU) composites to enhance the biodegradation efficiency of DBP. The results revealed that rice husk biochar, pyrolyzed at 300 °C, exhibits relatively safer and more stable physical and chemical properties, making it an effective immobilization matrix. Additionally, the optimal cultural conditions for Bacillus aquimaris in DBP biodegradation were identified as incubation at 30 °C and pH 7, with the supplementation of 0.15 g of yeast extract, 0.0625 g of glucose, and 1 CMC of Triton X-100. Algal biotoxicity results indicated a significant decrease in biotoxicity, as evidenced by an increase in chlorophyll a content in Chlorella vulgaris following DBP removal from the culture medium. Finally, microbial community analysis demonstrated that encapsulating B. aquimaris within alginate-Ca and WPU layers not only enhanced DBP degradation, but also prevented ecological competition from indigenous microorganisms. This novel approach showcases the potential of agricultural waste utilization and microbial immobilization techniques for the remediation of DBP-contaminated environments.

Effect of coffee husk biochar and inorganic NP fertilizer on soil properties, growth and yield of potato (Solanum tuberosum L.) on acidic soil of southwest Ethiopia

Soil acidity and low soil fertility due to nutrient leaching coupled with low inorganic fertilizer usage is a major cause of low crop yields across Southwest Ethiopia. Recently, biochar potential to improve soil fertility has gained significant attention but there are limited studies on the use of biochar in combination with inorganic fertilizers. A field experiment was, therefore, conducted to investigate the effect of combined application of biochar and inorganic NP nutrient on soil physicochemical properties, growth and yield of potato in Andiracha district, Southwestern Ethiopia. The experiment was laid out in randomized complete block design (RCBD) and replicated three times. The treatment consisted of four levels of biochar rates (0, 2.5, 5 and 7.5 t ha−1) and four fertilizer rates of (0, 75,100 and 125% of recommended N P rates). Data were analyzed using SAS version 9.3 Software. Analysis of variance showed that combined application of biochar and inorganic NP fertilizer had highly significant (p < 0.01) effect on days to flowering, stem number, plant height, total leaf area, total dry biomass, marketable tuber number per hill and harvest index and significant (p < 0.05) effect on marketable tuber weight and total tuber weight ha−1. Combined application of 7.5 ton ha−1 biochar with 165 kg N and 60 kg P ha−1 resulted highest tuber yield (42.64 t ha−1), that increased yield by 28.99% compared with recommended NP fertilizer alone (165 kg N ha−1 and 60 kg P ha−1), and by 76.6% compared to the control. The increase was mainly attributed to the improvement in soil physico-chemical properties especially soil pH, CEC, organic matter, total N and available P which is a reflection of increase in soil fertility. Consequently, it was determined that the best course of action for potato production in the area was to apply 7.5 tons of biochar ha−1 together with 165 kg N and 60 kg P ha−1. Therefore, the study recommends adoption of low cost biochar production techniques and capacity building to ensure satisfactory knowledge of biochar use and its adoption by potato growers for soil fertility management and enhanced crop productivity.

Assessing the Impact of King Coconut Husk Ash and Biochar, Combined with Chemical Fertilizer Application, on Enhancing Soil Fertility in Coconut Plantations

Sustainable soil fertility management is crucial for enhancing productivity in coconut plantations. This study investigated the synergistic effects of king coconut husk (KCH) ash, biochar, and chemical fertilizers on soil properties in a coconut plantation over a short period (4 months). Six treatments were applied: control, chemical fertilizers alone (F), fertilizers with ash (FA), fertilizers with biochar (FB), fertilizers with both ash and biochar (FAB), and fertilizers with half ash and biochar (FA1/2B). Strongly alkaline KCH ash contained significantly higher total and available potassium content levels than mildly alkaline biochar. Data indicated that KCH ash significantly enhanced soil available potassium, electrical conductivity, and organic carbon content compared to the control and F treatments over a short-term period. Even though biochar application demonstrated initial improvements in soil moisture content, a longer study duration may be required to evaluate its influence on other soil parameters comprehensively. Highlighting the synergistic benefits of KCH ash and biochar, FA1/2B treatment exhibited the highest combined index score based on physical, biological, and chemical soil indicators, suggesting its potential for optimizing agricultural outcomes. It emerged as the most promising approach, underscoring the value of exploring sustainable soil amendments derived from agricultural waste streams to promote soil fertility and sustainable coconut production.

Comparative Study for Propranolol Adsorption on the Biochars from Different Agricultural Solid Wastes.

Currently, large amounts of agricultural solid wastes have caused serious environmental problems. Agricultural solid waste is made into biochar by pyrolysis, which is an effective means of its disposal. As the prepared biochar has a good adsorption capacity, it is often used to treat pollutants in water, such as heavy metals and pharmaceuticals. PRO is an emerging contaminant in the environment today. However, there are limited studies on the interaction between biochars with PRO. Thus, in this study, we investigate the adsorption of PRO onto the biochars derived from three different feedstocks. The order of adsorption capacity was corn stalk biochar (CS, 10.97 mg/g) > apple wood biochar (AW, 10.09 mg/g) > rice husk biochar (RH, 8.78 mg/g). When 2 < pH < 9, the adsorption capacity of all the biochars increased as the pH increased, while the adsorption decreased when pH > 9, 10 and 10.33 for AW, CS and RH, respectively. The adsorption of PRO on biochars was reduced with increasing Na+ and Ca2+ concentrations from 0 to 200 mg·L-1. The effects of pH and coexisting ions illustrated that there exist electrostatic interaction and cation exchange in the process. In addition, when HA concentration was less than 20 mg/L, it promoted the adsorption of PRO on the biochars; however, when the concentration was more than 20 mg/L, its promoting effect was weakened and gradually changed into an inhibitory effect. The adsorption isotherm data of PRO by biochars were best fitted with the Freundlich model, indicating that the adsorption process is heterogeneous adsorption. The adsorption kinetics were fitted well with the pseudo-second-order model. All the results can provide new information into the adsorption behavior of PRO and the biochars in the aquatic environment and a theoretical basis for the large-scale application of biochar from agricultural solid wastes.

Influence of agro-wastes derived biochar and their composite on reducing the mobility of toxic heavy metals and their bioavailability in industrial contaminated soils

The agro-waste derived valuable products are prime interest for effective management of toxic heavy metals (THMs). The present study investigated the efficacy of biochars (BCs) on immobilization of THMs (Cr, Zn, Pb, Cu, Ni and Cd), bioaccumulation and health risk. Agro-wastes derived BCs including wheat straw biochar (WSB), orange peel biochar (OPB), rice husk biochar (RHB) and their composite biochar (CB) were applied in industrial contaminated soil (ICS) at 1% and 3% amendments rates. All the BCs significantly decreased the bioavailable THMs and significantly (p < 0.001) reduced bioaccumulation at 3% application with highest efficiency for CB followed by OPB, WSB and RHB as compared to control treatment. The bioaccumulation factor (BAF), concentration index (CI) and ecological risk were decreased with all BCs. The hazard quotient (HQ) and hazard index (HI) of all THMs were <1, except Cd, while carcer risk (CR) and total cancer risk index (TCRI) were decreased through all BCs. The overall results depicted that CB at 3% application rate showed higher efficacy to reduce significantly (p < 0.001) the THMs uptake and reduced health risk. Hence, the present study suggests that the composite of BCs prepared from agro-wastes is eco-friendly amendment to reduce THMs in ICS and minimize its subsequent uptake in vegetables.

Use of biochar and NPK fertilizer in soybean cultivation in Alfisol to improve soil physical properties and plant growth

Abstract The decrease in soil properties due to using artificial fertilizers requires finding a solution, one of which is using biochar. This research aims to assess the effect of the application of rice husk biochar and NPK compound fertilizer on the physical properties of Alfisols and soybean growth. The study was conducted from March to June 2023 on Alfisol of Kwangsan Village, Jumapolo, using a Randomized Complete Block Design (RCBD) with 10 treatments and 3 replications. The study showed that combining rice husk biochar and NPK compound fertilizer improved soil physical properties: soil C-Organic levels, field capacity, soil porosity, and soil water retention levels, and reduced soil bulk weight. The treatments also increased soybean growth: plant height, number of leaves and branches. Application of 25% NPK compound fertilizer (75kg ha-1) and 100% rice husk biochar (10 tons ha-1) is suggested to progress soil physical properties and soybean plant development in Alfisols.

Rice husk biochar for carbon sequestration, soil fertility and plant health improvement: A review

Carbon dioxide (CO2) is considered one of the ozone layer gases that contribute to climate change. As the area under agricultural use expands, the level of CO2 from soil as an agricultural by-product increases in the atmosphere. Burning rice husks in open air, decomposing plant materials among other activities release CO2 directly to the atmosphere. Rice husks as a by-product of rice production in Kenya has both the potential to be a source of greenhouse gas (GHG) and production of biochar. Production and deposition of rice husk biochar (RHB) into soil is thought to be one of the viable options for permanent carbon storage with related benefits to soil fertility. This review seeks to consolidate information from various studies that highlight the innovative way of using RHB in combating climate change, improving soil fertility, plant health and crop yields. Studies that have demonstrated beneficial use of RHB were evaluated to prepare this review. When RHB is used as a soil amendment, it has the ability to increase soil carbon storage, mitigate 10% of the current anthropogenic carbon emissions, improve pH and raise Cation Exchange Capacity (CEC), increase available plant nutrients, enhance inherent plant immunity, increase crop yields and improve water quality by increasing retention of nutrients and agrochemicals for plant utilization. A review of the benefits of RHB use in agriculture and climate change mitigation will enhance its adoption. The review further emphasizes the usefulness of pyrolysis in turning organic waste into bioenergy, compost and other beneficial products while protecting the environment. Key Words: Carbon dioxide, climate change, global warming, innovation, ozone layer, temperature.

Synergistic photocatalysis of oxygen-enriched vacancy BiOBr based on rice husk biochar: Efficient seawater purification achieved by carrier directional migration

Addressing seawater pollution is crucial for the efficient utilization of seawater resources. Employing solar-driven seawater purification emerges as an ideal solution for the future renewable energy landscape. Herein, biomass carbon and oxygen-enriched defect materials were selected to design a high-performance photocatalyst for seawater purification. The strategic combination of defect energy levels and electron-conducting carbon enhances the directional migration and separation of photogenerated particles, thereby boosting the overall photocatalytic efficiency in seawater purification. In the simulated seawater experiment, ROV-BOB/RHC-3 exhibits significant resistant to conventional ions interference during purification. Transitioning to real seawater experiments, ROV-BOB/RHC-3 exhibits impressive removal performance for RhB and TC, achieving substantial purification in 10 L of seawater under natural sunlight. Combine free radical trapping experiments and electron spin resonance (ESR) analysis shows that reactive oxygen species (•O2- and 1O2) are responsible in purification. The project provides a practical and effective basis for further research on efficient biomass carbon-based photocatalysts to seawater purification.

Net CO2 removal of rice husk biochar as soil amendment depending on energy reuse in the production stage

Net CO2 removal of rice husk biochar as soil amendment depending on energy reuse in the production stage

Effects of Biochar Type on the Growth and Harvest Index of Onion (Allium cepa L.)

This study examined using peanut shells, rice husks, and cocoa husks as soil conditioners to boost yields in Allium cepa var. Alvara onions. Three types of biochar and four application rates (1%, 1.5%, 3%, and 5%) were compared to a control with no biochar. The biochars had different nutrient makeups, with cocoa husk biochar (CHB) containing the most essential elements. While overall plant growth (height, leaves, and roots) was not significantly affected (p &gt; 0.05) by any biochar type compared to the control, some plant parts responded differently. CHB (5%) and peanut husk biochar (PHB) (1%) yielded the tallest onion plants (71 and 65 cm), while 1% rice and cocoa biochar resulted in the shortest (below 42 cm). PHB (3% and 5%) produced the longest roots (9 cm), while 1.5% rice husk biochar (RHB) had the shortest. Biochar application had no significant effect on leaf count. However, specific application rates of RHB and PHB increased the harvest index (HI), indicating more efficient yield allocation. HI values &gt; 0.85 were obtained with specific biochar rates (e.g., 1.0–1.5% PHB, 1.5–5% RHB, or 5.0% CHB).

Enriched rice husk biochar superior to commercial biochar in ameliorating ammonia loss from urea fertilizer and improving plant uptake

Adding value to agricultural leftovers and turning them into biochar is a viable way to replenish soil nutrients and boost crop productivity. To further validate the efficacy of enriched rice husk biochar, an incubation study and a pot experiment were conducted: (1) to describe the effect of enriched rice husk biochar addition on soil total N, soil exchangeable NH4+ and available NO3− and (2) to describe the effect of enriched rice husk biochar on improving N, P, K, Ca, and Mg uptake, use efficiency, and dry matter production of rice plants. The amount of NH3 loss that was considerably reduced by rice husk biochar at 5 and 10 t ha−1 was 34 % lower than the control. The availability of soil total N, exchangeable NH4+, available NO3−, available P, and exchangeable cations was greatly enhanced by the addition of rice husk biochar. Due to the effective nutrient uptake that occurs with an increase in soil nutrient level, the physical growth of the rice plant (height, tiller number, greenness, and panicle number) increeased significantly in treatments supplemented with 5 t ha−1 rice husk biochar. When rice plants were treated with 5 t ha−1 rice husk biochar, their absorption of N, P, and K increased by >80 %, respectively. The production of dry matter in rice plants increased as a result of the increased N intake. The application of 5 t ha−1 of rice husk biochar enhanced the soil nutrients by reducing NH3 loss and augmenting soil nutrients for efficient plant absorption, as demonstrated by the favourable enhancement of soil macro- and micronutrients and biomass of rice plants.

Improved tomato development by biochar soil amendment and foliar application of potassium under different available soil water contents

The use of carbonaceous materials such as biochar has been considered an innovative solution in agriculture, especially to mitigate dry events caused by climate change. Biochar can improve water holding capacity, physical and chemical properties of soil, and increase the productivity of agricultural systems. However, underlying physiological mechanisms remain poorly understood. Mineral supplementation with potassium nitrate (KNO3) via foliar application is another promising strategy in agricultural management under irrigation deficit. Thus, we investigated the combined effects of biochar and foliar application of KNO3 on growth, yield, and physiology of tomato plants under different irrigation regimes. Results did not indicate a synergistic effect of biochar and foliar application of KNO3. Biochar application alleviated tomato plant stress under deficit irrigation, with plants showing better functioning of photosynthetic apparatus, higher yield, and better fruit quality, as well as increased water use efficiency. Coffee husk biochar (K-rich feedstock) fully met the tomato plant’s demand for K and partially met the demand for some other elements (P, Mg, Fe, Zn, Mn, and Cu). Although positive effects of KNO3 application was verified for some physiological and fruit quality components, overall, foliar application of KNO3 did not improve tomato yield. It is concluded that biochar soil amendment can be a promising practice to increase yield and quality of tomato fruits under deficit irrigation. Therefore, biochar-based fertilizer can be an alternative K source that also provides stable carbon to soil and helps to mitigate stress caused by prolonged drought.

Characteristics of rice husk biochar briquettes with municipal solid waste cassava, sweet potato and matooke peelings as binders

Rice husks are not readily biodegradable making their disposal challenging due to the common disposal method of open burning which has negative environmental effects. Additionally, banana, sweet potato and cassava peelings form a large percentage of organic municipal solid waste. Therefore, this study developed rice husk biochar briquettes with organic municipal peelings waste as binders. Rice husks biochar was formed via carbonization processes in a step-down kiln at temperatures ranging between 400 and 500 °C. Organic binders were mixed with the rice husk biochar at different ratios of 10% and 15% before being compacted at a pressure ≤ 7 MPa into briquettes. Thermogravimetric results showed that the developed briquettes had high ash contents ranging from 44% to 47%. Rice husk biochar briquettes with the highest particle density were observed for briquettes with 15% cassava peel binder at 427.1 kg/m3. The highest HHV and maximum attainable flame temperature of 21.75 MJ/kg and 828.7 °C were obtained for rice husk biochar briquettes with 15% matooke peeling organic binder. For all rice husk biochar briquettes, increasing the organic peeling binder had a positive impact of reducing the ash content, while at the same time increasing the peak temperatures, thus contributing to their enhanced thermal stability.

Reducing Methane Emissions with Humic Acid–Iron Complex in Rice Cultivation: Impact on Greenhouse Gas Emissions and Rice Yield

Methane emissions from flooded rice paddies are a major source of atmospheric methane and represent a significant greenhouse gas with high climate-forcing potential due to anthropogenic activities globally. For sustainable agriculture, it is necessary to find effective methods for mitigating greenhouse gas emissions without reducing crop productivity. We investigated mechanisms to reduce methane emissions during rice cultivation by applying rice straw, rice husk biochar, humic acid, and a humic acid–iron complex, assessing greenhouse gases and rice yield over a single season. The results demonstrated that the treatment plots with rice straw and the humic acid–iron complex significantly reduced methane emissions (563 ± 113.9 kg ha−1) by 34.4% compared to plots treated with rice straw alone (859 ± 126.4 kg ha−1). Rice yield was not compromised compared to the control group treated with only NPK fertilizer, and growth in terms of plant height and tiller number was enhanced in the plots treated with rice straw and the humic acid–iron complex. Conversely, the plots treated solely with rice husk biochar and humic acid did not show a methane reduction effect when compared to the NPK treatment. The humic acid–iron complex has demonstrated potential as a methane mitigation agent with practical applicability in the field, warranting further long-term studies to validate its effectiveness.

Magnetic iron‐oxide coffee husk and khat waste biochar nanocomposites for removal of methylene blue from aqueous solution

AbstractWastewater from the textile and dyeing industries contains hazardous dyes. This study aims to determine the effectiveness of magnetic biochar nanocomposites synthesized from khat leftovers (KLs) and coffee husks (CHs) in removing methylene blue (MB) from wastewater. Magnetic biochar nanocomposites were synthesized by pretreating 25 g of biomass with a 12.5 mmol mixture of FeS and FeCl3 at a 1:1 molar ratio, followed by pyrolyzing at 300°C for 1 h. The resulting products were analyzed using X‐ray diffraction, Fourier transform infrared, scanning electron microscope, and Brunauer‐Emmett‐Teller. The results showed that the adsorbents are amorphous, and the activated biochars, are more porous and contain various functional groups such as C‐O, C = C, O‐H, C‐H, and Fe‐O. When 0.2 g of pristine biochars of CH and KL were applied to 20 mL aqueous solutions containing 20 mg/L of MB at pH 7.5 and 25°C, they removed 44.73% and 75.26% of MB, respectively. However, the resulting nanocomposites exhibited a maximum removal efficiency of 99.10% and 99.23% with magnetic iron oxide‐CH biochar nanocomposite (Fe3O4‐CHBNC) and magnetic iron oxide‐KL biochar nanocomposite (Fe3O4‐KLBNC), respectively, with maximum adsorption capacities of 51.02 and 78.13 mg/g. The reusability study also showed removal efficiencies of 77.57% and 83.49% up to six‐cycle reuse.

REINFORCEMENT OF COMPRESSED STABILIZED EARTH BLOCKS WITH BIOCHAR RESULTING FROM USE OF AGRO-INDUSTRIAL WASTE

ABSTRACT Over the past few decades, the transformation and utilization of materials obtained from agricultural residues as a circular economy strategy have been extensively discussed. Rice husk has received special attention due to the presence of biogenic oxides or biosilica (Gomez-Vazquez et al., 2022; Shafigh et al., 2014; A. B. Souza et al., 2021). This study aimed to evaluate the technical feasibility of using rice husk biochar, a by-product of bioenergy utilization of this agroindustry waste, by developing a multi-factor statistical analysis during the formulation of compressed stabilized earth blocks (CSEB). A central composite experimental design was implemented to examine the contribution of factors such as the percentage of biochar (2.5–17%) and drying temperature (40–100°C) of the CSEB on its mechanical properties. The ANOVA analysis and response surface evaluation demonstrated that biochar up to 14.5% could be added while maintaining a minimum strength of 2MPa. Moreover, the drying temperature significantly affected the mechanical strength of the CSEB, and a complex interaction between clay and biochar was observed, allowing for high mechanical strength and adsorption capacities of the CSEB simultaneously.

Application of Hydroxyapatite Functionalized Magnetic Rice Husk Biochar for the Adsorption Removal of Cu(II) Ions from Aqueous Solutions

Application of Hydroxyapatite Functionalized Magnetic Rice Husk Biochar for the Adsorption Removal of Cu(II) Ions from Aqueous Solutions

Biochar and Azolla Effects on Soil Chemical Properties, Lead Content and Growth of Paddy

The objective of the study was to determine the influences of biochar amendments and Azolla sp application on soil chemical value, lead (Pb) content, and growth of paddy. The research was conducted in Growth Centre LLDIKTI I, Medan, Sumatera Utara, Indonesia, from April to July 2014. The research design used a factorial randomized block design with three replications. The first factor was Azolla sp application: without Azolla (A0); Azolla pinnata (A1); Azolla mikropilla (A2)] and the second factor was biochar amendment without biochar (B0); RSB-Rice straw biochar (B1), RHB-Rice husk biochar (B2), CPB-coconut peat biochar (B3), OPB-Oil Palm Empty Bunch biochar (B4)]. The result showed that the biochar amendment treatments had significant differences (P&lt;0.05) in all soil chemical values and growth parameters of paddy. The Azolla application showed significant differences (P&lt;0.05) in plant height, number of tillers, shoot dry weight, root dry weight, and Pb content in the root. The interaction among the Azolla sp and the biochar amendments showed significant differences (P&lt;0.05) in a number of the tillers. It was concluded that the application of rice husk biochar and Azolla microphylla was able to increase soil chemical properties, increase the growth of paddy, and also increase the Pb content in soil, leaves, and roots.