Rice Husk Research Articles

Biomass source influence on hydrogen production through pyrolysis and in line oxidative steam reforming.

This study evaluates the potential of several biomasses differing in nature and composition for their valorization by pyrolysis and in-line oxidative steam reforming. The first task involved the fast pyrolysis of the biomasses in a conical spouted bed reactor at 500ºC, in which product yields were analyzed in detail. Then, the oxidative steam reforming of pyrolysis volatiles (gases and bio-oil) was approached in a fluidized bed reactor. The reforming experiments were performed at 600 ºC, with an steam/biomass (S/B) ratio of 3 and catalyst (Ni/Al2O3) space times of 7.5 and 20 gcat min gvol-1. Concerning equivalence ratio (ER), a value of 0.12 was selected to ensure autothermal operation. Remarkable differences were observed in H2 production depending on the type of biomass. Thus, pine wood led to a H2 production of 9.3 wt%. The lower productions obtained with rice husk (7.7 wt%) and orange peel (5.5 wt%) are associated with their higher ash and fixed carbon content, respectively, which limit the efficiency of biomass conversion to bio-oil. However, in the case of the microalga, the poor performance observed is due to the lower conversion in the reforming step toward gases due to the composition of its pyrolysis volatile stream.

A master plot approach on rice husk decomposition through pyrolysis and kinetic elucidation using iso-conversional models

The present study aimed at predicting the intricate mechanism followed by the pyrolysis of locally available rice husk, uses noval modified master plots through continuous slope-based differential techniques. An average apparent activation energy was found in the range of 187.29 (KAS model) and 199.85 kJ mol−1 (OFW model), respectively. The rice husk revealed higher volatile matter; 54.51 wt-%, HHV; 18.42 MJ kg−1and a critical pyrolysis zone around 250 to 550 °C with two sharp peaks through differential thermogravimetric analysis. Using Karl–Pearson correlation, experimental curve showed highest correlation coefficient of 0.94 and 0.75 with respect to A2 and A3 models (Avrami–Erofeev) for g( α). However, for Z( α), the process is limited by first-order multi-diffusion processes (D1) coupled with solid phase surface reaction (F3) showing correlation coefficient of 0.8. The experimental data worked out the generalized model of f( α) as f( α) = 12.74 α3 – 24 α2 + 12.6 α - 0.92 with R2 value of 0.99, narrating the usage of master plots for better understanding of the process.

Comparative study on tensile and morphological properties of resin and rice husk reinforced polymer composite gyroid lattice structures

Abstract This study aims to compare the tensile behaviour of 3d printed resin and rice husk-reinforced resin-based gyroid lattice structures. The work was completed in two phases, firstly a resin gyroid lattice structure with two design configurations of unit cell sizes (3, 4, 5, and 6) and solidity percentages (30, 40, and 50) was developed according to the ASTM638 (4) standard. The 12 designs were manufactured using VAT polymerization additive manufacturing and investigated for tensile strength. In the second phase, the poorest tensile testing results were chosen to develop the rice husk-reinforced resin samples with a mixing proportion of 10-20-30%. The experiment results revealed that the fracture is localized inside the gauge length according to the standard. Remarkably, the rice husk composite-based gyroid lattice samples exhibit 4.29, 6.55, and 9.35 times higher tensile strength than the selected resin sample (U3-30). Additionally, a homogeneous distribution of rice husk particles has been observed in the micrograph analysis (SEM).

Performance of ZZ (Zamioculcas zamiifolia) Cultivars on Different Organic Potting Mixture

An experiment was carried out at the research cum instructional farm, Department of Horticulture, School of Agricultural Sciences, Nagaland University, Medziphema, India (2022-2023). The experiment was laid out in completely randomized design (CRD) with 14 treatments and 3 replications. The treatments consisted of organic substrates (T1: FYM, T2: Vermicompost, T3: Used tea leaves, T4: Forest litter, T5: Cocopeat, T6: Perlite and T7: Rice husk) and 2 cultivars (C1: Super Nova and C2: Black Raven). The rooted plants of ZZ cultivars were planted in different organic substrates along with garden soil and sand in the ratio of 1:1:1. Among the cultivars, C1 (Super Nova) was found to be significantly better than Black Raven. Amongst the organic substrates, T5 (Garden soil + sand + cocopeat) was found to be statistically superior in all observed parameters except for plant height which was found to be in maximum in T4 (Garden soil + sand + forest litter). The same treatment of T5 exhibited the highest profit (Rs. 12250) and benefit cost ratio (1.89) on ZZ cultivar Black Raven.

Community Based Identification of Energy-Related Needs and Priorities of Poor Communities In Karangmojo Village, Yogyakarta

The current fossil energy crisis is the right momentum to develop renewable energy potential. The purpose of this study is to identify renewable energy utilization programs in Karangmojo Village, in order to meet the energy needs of poor communities. The study uses in-depth interviews with the community to obtain various energy problems faced, especially for poor communities and farmers. We find various renewable energy development programs, including: Biogas Energy Package (BGEP) for cooking purposes, Biogas Energy Package (BGEP) for local entrepreneur, Biodiesel Energy Package (BDEP) for household and irrigation system, and Biomass Energy Package (BMEP) from rice husk. This study is also equipped with a review of stakeholder analysis

Effect of rice hull biochar treatment on net ecosystem carbon budget and greenhouse gas emissions in Chinese cabbage cultivation on infertile soil

Biochar, with its potential to enhance soil fertility, sequester carbon, boost crop yields and reduce greenhouse gas emissions, offers a solution. Addressing the challenges posed by climate change is crucial for food security and agriculture. However, its widespread adoption in agriculture remains in its infancy. This study assessed the effects of rice hull biochar on cabbage production and greenhouse gas emissions, especially nitrous oxide (N2O). A trial, employing a randomized block design in triplicate was conducted from September 13 to November 23, 2022, where "Cheongomabi" cabbage was cultivated with N-P2O5-K2O fertilization at 32-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-$$\\end{document}7.8-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-$$\\end{document}19.8 kg 10a−1. Additional fertilizer was applied twice post-sowing. The Biochar application rates were control = 0 ton ha−1, B1 = 1 ton ha−1, B3 = 3 ton ha−1, and B5 = 5 ton ha−1. The aboveground biomass of autumn cabbage harvested 82 days after sowing was 2.40–2.70 kg plant−1 in the control and biochar treatments (B1, B3, and B5), with no significant differences (p > 0.05). Cumulative CO2 emissions during cultivation varied across treatment groups, with initial and cumulative emissions of 10.40–17.94 g m−2 day−1 and 3.63–4.43 ton ha−1, respectively. N2O emissions decreased with higher biochar application: reductions of 2.9%, 25.4%, and 41.1% in the B1, B3, and B5 treatments, respectively, compared to the control. The biochar application had no significant impact on yield but curbed soil emissions, Net ecosystem carbon balance during cabbage cultivation ranged from 0.42 to 3.41 ton ha−1 for the B1, B3, and B5 treatments, respectively, compared to control. Overall, the study underscores biochar’s role in mitigating emissions and boosting soil carbon during cabbage cultivation in fall.

Modified Rice Husk Waste‐Based Filter for Wastewater Treatment: Pilot Study and Reuse Potential

AbstractThis study investigates a rice husk waste‐based filter (RHW‐BF) for the treatment of graywater (GW) and primary treated wastewater (PTW). The RHW‐BF comprises three layers: coarse sand, chemically modified rice husk (MRH), and gravel. Continuous runs (Run I, II, III) assessed chemical oxygen demand, total suspended solids, total dissolved solids, and turbidity removal. Run (I) for GW achieved high removal: 73.7 %, 73.4 %, 74.6 %, and 92.6 %. Subsequent runs showed decreasing efficiencies due to media saturation. Similar trends occurred for PTW, with Run (I) achieving significant removal: 70.3 %, 69.0 %, 44.2 %, and 90.2 %. MRH particles played a crucial role in sustainable pollutant removal. The study compares treated wastewater with the World Health Organization and Egyptian limits, demonstrating its suitability for reuse in irrigation, agriculture, or sewer discharge.

Effect of temperature on the ability to synthesize SiC from rice husks

Abstract Agricultural production in Vietnam annually generates a substantial volume of by-products and waste, with rice husks constituting the predominant fraction. Due to their meager economic value, rice husks are typically deemed agricultural waste and are commonly disposed of through incineration or discharge into rivers, contributing significantly to environmental pollution. In this investigation, rice husks were employed as the principal raw material for synthesizing silicon carbide. A blend of rice husks and silica gel in a ratio of 1.4/1 was subjected to sintering in a CO2 environment within the temperature range of 800 – 1200 oC for 30 minutes. The chemical composition of the resultant product post-pyrolysis was ascertained in accordance with the ISO 21068-2:2008 standard. The capacity for SiC formation was further assessed utilizing Fourier transform infrared spectroscopy and X-ray diffraction. The outcomes revealed that the optimal temperature for SiC synthesis was 1200 oC. The composition of the sample post-pyrolysis was determined as 20.4% SiC, 51.2% SiO2, and 26.4% C (%wt.). The primary phase constituents encompass amorphous carbon, cristobalite, α-SiC, and β-SiC. Scanning Electron Microscopy/ Energy Dispersive X-ray imaging of the product at 1200 oC exhibited dispersed SiC crystals on a SiO2-C substrate. The presence of SiC suggests the potential application of the product as a wear-resistant material.

Co-hydrothermal carbonization of municipal sludge and agricultural waste to reduce plant growth inhibition by aqueous phase products: Molecular level analysis of organic matter

The organic matter molecular mechanism by which combined hydrothermal carbonization (co-HTC) of municipal sludge (MS) and agricultural wastes (rice husk, spent mushroom substrate, and wheat straw) reduces the inhibitory effects of aqueous phase (AP) products on pak choi (Brassica campestris L.) growth compared to HTC of MS alone is not clear. Fourier-transform ion cyclotron resonance mass spectrometry was used to characterize the differences in organic matter at the molecular level between AP from MS HTC alone (AP-MS) and AP from co-HTC of MS and agricultural waste (co-Aps). The results showed that N-bearing molecules of AP-MS and co-Aps account for 70.6 % and 54.2 %–64.1 % of all molecules, respectively. Lignins were present in the highest proportion (56.3 %–78.5 %) in all APs, followed by proteins and lipids. The dry weight of co-APs hydroponically grown pak choi was 31.6 %–47.6 % higher than that of the AP-MS. Molecules that were poorly saturated and with low aromaticity were preferentially consumed during hydroponic treatment. Molecules present before and after hydroponics were defined as resistant molecules; molecules present before hydroponics but absent after hydroponics were defined as removed molecules; and molecules absent before hydroponics but present after hydroponics were defined as produced molecules. Large lignin molecules were broken down into more unsaturated molecules, but lignins were the most commonly resistant, removed, and produced molecules. Correlation analysis revealed that N- or S-bearing molecules were phytotoxic in the AP. Tannins positively influenced the growth of pak choi. These results provide new insights into potential implementation strategies for liquid fertilizers produced from AP arising from HTC of MS and agricultural wastes.

Removal of silica in rice husk derived Ni/biochar modifies reaction intermediates formed and minimizes coking in steam reforming of glycerol

Metal/biochar catalyst features with the advantages for easy recovery of chemical energy of biochar carrier and metal species via simply combustion. Another unique feature of biochar carrier is intrinsic inorganic species, which might also interact with metal species in resulting catalyst. This was investigated herein by synthesis of the Ni/biochar with rice husk-derived biochar carrier pretreated with NaOH for removal of SiO2 and evaluation of the resulting catalysts in steam reforming of glycerol. The solid phase reactions between NaOH and biochar (mass ratio: 2) plus subsequent washing removed 94.6% of ash (mainly SiO2). This formed Ni/biochar of fragmented surface with specific surface area increasing from 207.8 to 457.4 m2g-1 and simultaneously increasing mesopore percentage from 15.5% to 24.0%. NaOH treatment also effectively removed significant portion of both Lewis and Brønsted acidic sites but created abundant alkaline sites. These drastically enhanced nickel dispersion and activity for steam reforming. In-situ IR characterization suggested enhanced adsorption/activation of CO2 and H2O over Ni/biochar treated with NaOH (Ni/biochar-NaOH), which mitigated accumulation of coke precursors bearing CO or CC via accelerated gasification reactions. This led to the reduced amount of coke (mass ratio to catalyst) from 193.4% to 94.7% over Ni/biochar treated with 2-fold of NaOH or to 111.3% over Ni/biochar treated with 1-fold of NaOH. The coke formed was mainly catalytic type in form of carbon nanotube over Ni/biochar-NaOH. The superior resistivity to coking originated from developed pores, enhanced Ni dispersion and abundant alkaline sites from the NaOH treatment.

Eco-friendly building materials: full-scale replacement of mineral aggregates with rice husk

In a context where sustainable construction and ecology are increasingly central, the construction industry is constantly seeking alternative materials that are both economical and eco-friendly. Concurrently, global rice production generates significant amounts of rice husks, often considered as low-value waste. This study deviates from traditional approaches that favor the use of rice husk ash (RHA) as a mineral additive, to explore the potential of rice husks themselves as a complete substitute for sand in concrete formulations. After meticulous characterization of the physicochemical properties of rice husks, several concrete formulations were designed and subjected to a battery of tests. The results are promising. They show that concrete based on rice husks exhibits satisfactory mechanical properties for a wide range of applications, from slabs to load-bearing walls. The compressive strength varies between 0.56 MPa and 5.41 MPa depending on the composition, while the thermal conductivity falls within a range of 0.070 W m−1 K−1 to 0.129 W m−1 K−1, which is comparable to other agro-concretes. This research highlights the promising potential of rice husks as a sand substitute material in concrete. It thus paves the way for more ecologically responsible and economically viable construction alternatives, while proposing a value-added solution for a widely available agricultural byproduct.

Demineralization effects on physicochemical and combustion characteristics of biomass: Insights into distributed kinetics, flue gas evolution, and slag formation

Biomass as the only carbon-bearing renewable energy has enormous potential to challenge the established energy structure dominated by fossil resources, and incineration technology is one of the most direct and efficient pathways for utilizing biomass resources, unfortunately enduring the inevitable sintering and slagging problems owing to the excessive alkali metals. Herein, we comparatively investigated the effects of five leaching solvents (water, acetic acid, wood vinegar, hydrochloric acid, and oxalic acid) on the physicochemical properties and ash-removal capabilities of wheat straw (WS) and rice husk (RH), with a view to achieving better performance in the subsequent combustion characteristics, kinetic examination, flue gas, and slag evolution. Results indicated with ionization ability increased (water < acetic acid < hydrochloric acid), the WS exhibited a strong demineralization performance (maximum 61.1%), further leading to a steep weight loss in its combustion characteristic curve at approximately 350 °C and a delayed peak temperature after the removal of alkali metal. Multiple distributed activation energy model and sensitivity analysis revealed that leaching pretreatment enhanced the activation energy (189–191.8 kJ mol−1) and optimized energy distribution at the preliminary stage of the combustion reaction. In addition, the absence of alkali metals suppressed the catalytic oxidation reaction in the flue gas, remarkably limiting the formation of CO2 but facilitating the release of CO and CH4. Meanwhile, a considerable optimal in biomass ash slagging, in which the initial temperature of the liquid phase slag for WS ash increased to 991 °C. Notably, HCl showed the strongest demineralization performance among the five leaching solvents during pretreatment, but the high-temperature slag content was still higher than that of acetic acid. Therefore, slagging performance is not only associated with the demineralization ability of leaching solvents, but also with ash composition.

Biochar boosted high oleic peanut production with enhanced root development and biological N fixation by diazotrophs in a sand-loamy Primisol

Peanut yield and quality face significant threats due to climate change and soil degradation. The potential of biochar technology to address this challenge remains unanswered, though biochar is acknowledged for its capacity to enhance the soil microbial community and plant nitrogen (N) supply. A field study was conducted in 2021 on oil peanuts grown in a sand-loamy Primisol that received organic amendments at 20 Mg ha−1. The treatments consisted of biochar amendments derived from poultry manure (PB), rice husk (RB), and maize residue (MB), as well as manure compost (OM) amendment, compared to no organic amendment (CK). In 2022, during the second year after amendment, samples of bulk topsoil, rooted soil, and plants were collected at the peanut harvest. The analysis included the assessment of soil quality, peanut growth traits, microbial community, nifH gene abundance, and biological N fixation (BNF) rate. Compared to the CK, the OM treatment led to an 8 % increase in peanut kernel yield, but had no effect on kernel quality in terms of oil production. Conversely, both PB and MB treatments increased kernel yield by 10 %, whereas RB treatment showed no change in yield. Moreover, all biochar amendments significantly improved oilseed quality by 10–25 %, notably increasing the proportion of oleic acid by up to 70 %. Similarly, while OM amendment slightly decreased root development, all biochar treatments significantly enhanced root development by over 80 %. Furthermore, nodule number, fresh weight per plant, and the nifH gene abundance in rooted soil remained unchanged under OM and PB treatments but was significantly enhanced under RB and MB treatments compared to CK. Notably, all biochar amendments, excluding OM, increased the BNF rate and N-acetyl-glucosaminidase activity. These changes were attributed to alterations in soil aggregation, moisture retention, and phosphorus availability, which were influenced by the diverse physical and chemical properties of biochars. Overall, maize residue biochar contributed synergistically to enhancing soil fertility, peanut yield, and quality while also promoting increased root development, a shift in the diazotrophic community and BNF.

Mesoporous silica aerogels for sunflower oil refining and investigation of their adsorption performance

AbstractInvolving a succession of oil refining stages for edible oil production, a notable constraint lies in the necessity to employ diverse adsorbents at various steps within these processes. This study investigates the synthesis of mesoporous silica aerogels from rice husk ash, comparing their efficacy in physical sunflower oil refining with earth clay (Bentonite) and commercial silica (Trisyl). Tetraethyl orthosilicate (TEOS) impact during aging was analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and N2 adsorption-desorption analyzer to examine alterations in the structure of silica aerogels. The surface areas of TEOS-doped silica aerogel (TSA) and non-TEOS-doped silica aerogel (NTSA) were 296.18 and 267.06 m²/g. Mesoporous silica aerogels were evaluated for their ability to reduce free fatty acids (FFA), peroxide value (PV), phosphorus, and color pigments in sunflower oil. TSA and NTSA demonstrated significant FFA removal, with TSA at 3 wt.% achieving the highest performance of 32.2%. TSA also effectively reduced PV and phosphorus compared to NTSA, Bentonite and Trisyl, exhibiting performance similar to Bentonite in the bleaching process. TEOS-doped silica aerogels have shown promise as adsorbents for impurity removal in sunflower oil and has emerged as the potential adsorbent that can comprehensively and effectively meet the requirements of many edible oil physical refining applications in a singular step. Graphical Abstract

Salt slag and rice husk ash as raw materials in zeolite synthesis: Process optimization using central composite rotational design

The growing demand of zeolites for many industrial applications has led to a search for eco-friendly alternatives for their production, in an attempt to reduce costs, save natural resources and alleviate the associated environmental impacts. In the present study, hazardous aluminum salt slag (aluminum source) and rice husk ash (silicon source) were used as secondary raw materials to synthesize sustainable NaP-type zeolites through a hydrothermal process. A central composite rotational experimental design was applied to evaluate the effect of the reaction time and hydrothermal temperature on the obtained zeolites crystallinity. Using the proposed experimental design, temperatures between 85 and 115 °C and different reaction times (2–28 h) were tested. It was found that the interaction between the variables (time and temperature) and both variables, independently, exerted a significant influence on the crystallinity of the zeolites. The optimal experimental conditions (105 °C and 20 h), statistically determined, enabled a high degree of crystallinity (>73%) to be achieved. Thus, the use of hazardous aluminum and agri-food wastes as unconventional precursors for the production of zeolites represents a sustainable alternative to manage these wastes, by transforming them into secondary raw materials.

Combustion and mechanical properties of pellets from biomass and industrial waste

Experimental research findings are reported on the impact of industrial waste additives on the mechanical properties of pellets, their ignition and combustion. The compositions under study consisted of wood sawdust with coal slime/peat/a mixture of straw and rice husk. Composite pellets exhibited high moisture resistance and durability when subjected to vibration. The respective coefficients were 6–32 % higher than for sawdust without additives. The ignition characteristics of wood pellets tended to worsen when additional components were used in their composition. The ignition delay times increased by a factor of 3–4. In most cases, the use of additives increased the combustion duration of pellet fuels. The greatest environmental benefits in terms of carbon oxides were gained from mixtures of straw with rice husk and coal slime. СО2 and СО emissions decreased by 10–20 % and 10–54 %, respectively. A high nitrogen content in peat, coal slime and straw led to 5–94 % higher emissions of NOx for composite pellets. Using plant biomass and peat reduced the concentrations of sulfur oxides almost 3-fold. The results of multi-criteria analysis covering 13 energy, operational, economic and environmental components suggest that the difference in the relative efficiency indicator of wood pellets and compositions with industrial waste additives is 4.4–6.5 %.

Analysis on different materials for enhancing axial compression capacity of reinforced concrete

Compressive strength is one of the most important properties of concrete. Nowadays, a great variety of studies are delivered to analyse the effects of different materials on the compression capacity of concrete. This paper mainly focuses on some of these materials including basalt fiber, succinic acid, rice husk, Robo sand, glass sand, cattle manure ash (CMA) and metakaolin. Based on the researches, most of them showed significant positive effect on concretes compressive strength. However, it is also noticed that most of the researches only investigated the effects of single materials. The effects of combination of innovative materials are still unclear. In addition, the cost of adding these innovative materials is still unknown, which may lead to the difficulty in implementation. Finally, this paper also aims to reveal the common features of materials that can enhance the compression capacity of concrete, which might be a signal implying the potential of untested materials to improve concretes compressive strength.

Study on the Effect of Thermal Assisted Combined Plant-Based Biomass Conditioning on Dehydrated Sludge Bio-Drying

In recent years, the production of municipal sludge has gradually increased, and finding suitable sludge treatment and disposal technologies is an urgent problem that needs to be solved. Bio-drying of sludge is a relatively efficient and convenient drying method, but currently, there are still problems with unstable drying effects and high moisture content of dried products, which limits the subsequent utilization of bio-drying products. This article uses a thermal assisted bio-drying device that simulates carbonization waste heat reflux, and uses corncob, straw, sawdust, and rice husk as conditioners to carry out bio-drying of dehydrated sludge. The influence of the types and ratios of conditioner under thermal assistance on the bio-drying of dehydrated sludge is explored. The results showed that the moisture removal efficiency of the corncob and straw groups was better, and their material moisture content could be reduced to below 10% within 24 h. The lower calorific value of straw-sludge drying products was the highest, at 11,608.8 kJ/kg. The best conditioner under the conditions of this experiment was straw, and the drying effect was best when the mass ratio of dehydrated sludge to straw was 4:1. The research results contribute to promoting the development of sludge bio-drying technology.

3D-interconnected N-doped porous carbon with hierarchical pore structure as a high-efficiency catalyst for H2S oxidation at room temperature

Nitrogen-doped porous carbons (NPCs) have been regarded as an efficient metal-free catalyst for H2S oxidation. However, critical factors affecting their desulfurization ability are still unclear, making it difficult to accurately adjust their desulfurization performance to meet industrial requirements. Herein, a novel 3D-interconnected NPC with hierarchical pore structure was synthesized by one-step “leavening” strategy using rice husk and (NH4)2C2O4 as a carbon source and foaming agent, respectively, for H2S oxidation at room temperature. Pyrolysis temperature is the major factor for physicochemical properties of NPCs, and breakthrough sulfur capacity of the optimal NPC reaches up to 1036.68 mg/g, which can remain stable during three desulfurization-regeneration cycles. Comparative experiment shows that H2S capacity of NPC is 1.8 and 4.0 times those of PC and NC, respectively, revealing the excellent desulfurization performance of NPC. The structure-effect relationships between H2S and NPC reveal that both textural and chemical properties of NPC, especially specific surface area, structural defect, and pyrrolic N, play dominant roles in H2S removal. It is very necessary to balance the relationship between textural performances and pyrrolic N to synthesize optimal NPC catalyst. This work provides a valuable reference for rational design of high-efficiency carbon-based catalysts for persistent desulfurization at room temperature.

Physiological characterization and bioactive compounds of promising accessions of cowpea (Vigna unguiculata L. Walp) in the Peruvian Amazon

Cowpea production in the Peruvian Amazon is increasing due to its ability to adapt to diverse environments, its contribution to soil conservation, and its versatility of uses. This crop is particularly valuable in human nutrition due to its high nutritional quality and nutraceutical properties of its bioactive compounds. The aim of the study was to evaluate the physiology of cowpea plants in accessions PER1005854, PER1005851, and PER12645, under the influence of rice husk mulch, screw tree litter, and oil palm fiber, as well as to determine the bioactive compounds present in the grains. This study aims to promote sustainable cowpea production, expose the nutritional aspects of the grains, and foster their consumption both locally and nationally. The experiment was conducted from November 2022 to March 2023, in Yurimaguas, Loreto, Peru. The application of organic mulches demonstrates a significantly positive impact on the growth of cowpea accessions during their vegetative phase. This effect is possibly attributed to increased water availability, as the mulch reduces soil evaporation. In particular, cowpea accessions PER12645 and PER1005851 exhibit desirable physiological characteristics for grain production, with short cycles of 71 days and higher yields of 1141 and 1125 kg/ha respectively. In contrast, accession PER1005854 is distinguished by its higher biomass production, reaching a value of 14497 kg/ha, a relevant trait for foliage production and its contribution to soil conservation. The bioactive compounds, such as proteins, lipids, and carbohydrates, present in the accessions PER1005854, PER1005851, and PER12645, are similar to those found in other legumes. However, the antioxidant activity of dark tegument cowpeas proved to be superior, particularly highlighted in accession PER12645 (black tegument) with 26.3 μmolTG/g, and in accession PER1005854 (dark red tegument) with 19.5 μmolTG/g. This characteristic is particularly important for consumption, as it is related to the ability to combat oxidative stress in the human body.