Enhanced copper recovery from low grade copper sulfide ores through bioleaching using residues produced by fermentation of agricultural wastes

Effects of residues produced by agricultural wastes fermentation(AWF)on low grade copper sulfide ores bioleaching,copper recovery,and microbial community were investigated.The results indicated that adding appropriate bulk of AWF made contributions to low grade copper sulfide ores bioleaching,which may be mainly realized through reducing the passivation layer formed by Fe3+hydrolysis.Improved copper recovery(78.35%)and bacteria concentration(9.56×10^(7)cells·mL^(−1))were yielded in the presence of 5 g·L^(−1)AWF.The result of 16S rDNA analysis demonstrated that microbial community was differentiated by adding AWF.Bacteria proportion,such as Acidithiobacillus ferrooxidans,Moraxella osloensis,and Lactobacillus acetotolerans changed distinctly.Great difference between samples was showed according to beta diversity index,and the maximum value reached 0.375.Acidithiobacillus ferrooxidans accounted for the highest proportion throughout the bioleaching process,and that of sample in the presence of 5 g·L^(−) AWF reached 28.63%.The results should show reference to application of agricultural wastes and low grade copper sulfide ores.

Preparation of Dicarboxyl Cellulose Nanocrystals from Agricultural Wastes by Sequential Periodate-Chlorite Oxidation

Agricultural waste straw is the renewable resource with the highest annual yield in the world.In value-added applications of agricultural waste,dicarboxyl cellulose nanocrystals(DCCs)are prepared from rice,wheat,and corn straw by sequential periodate-chlorite oxidation.In this study,DCCs from rice,wheat,and corn straw were characterized by transmission electron microscopy(TEM),Fourier transform infrared spectrometer,X-ray diffractometer(XRD),and thermal gravimetric analysis(TGA).The carboxyl content of the DCCs was also investigated.XRD results show that the crystallinity index decreased after sequential periodate-chlorite oxidation;however,the cellulose I structure was maintained.TEM results show that rod-shaped DCCs with an average length and width of 287.0 nm and 9.9 nm,respectively,were successfully prepared by sequential periodate-chlorite oxidation.The carboxyl content of the DCCs was around 3.9 mmol/g,and not affected by the type of straw.Experiments to study the removal of copper ions in aqueous medium were performed with the prepared DCCs.The adsorption capacities of copper ions were 131,162,and 144 mg/g for DCCs prepared from rice,wheat,and corn straws,respectively.The results show that DCCs prepared from rice,wheat,and corn straws by sequential periodatechlorite oxidation have potential for the removal of copper ions from aqueous medium.

Biochar derived from agricultural wastes and wood residues for sustainable agricultural and environmental applications

Lignocellulosic biomass can be circulated to produce many materials and products,including biochar.This study analyzed five different types of biochar produced from agricultural wastes and wood residues.The raw materials included three agricultural by-products:corncob,cassava rhizome,rice husk,and two types of wood residues:rain tree(Samanea saman(Jacq.)Merr.)and krachid(Streblus ilicifolius(Vidal)Corner.).The biochar were made in patented retorts with locally-appropriated technology at a temper-ature range of 450e500C.This research focuses on the primary physicochemical properties and biochar components,allowing biochar to become a vital material to support sustainable agriculture and the environment.Biochar properties used for agriculture consist of specific surface area,total pore volume,average pore diameter,pH,electrical conductivity(EC),and cation exchange capacity(CEC).The prop-erties that benefit the environmental purposes are the element:carbon(C),hydrogen(H),nitrogen(N),oxygen(O),and the molar ratio of H/C,O/C,and C/N.The study found that all five types of biochar contained suitable properties for soil amendment and carbon sequestration.However,significant dif-ferences were shown in specific surface area,average pore diameter,pH,CEC,and EC of various biochar.Based on O/C and H/C ratios,all five types of biochar persisted in soil from 100 to over 1,000 years.

Optimization of hydrogen production from agricultural wastes using mixture design

Hydrogen production from food waste,cattle manure,potato pulp and pig manure was optimized through using mixture design in this study.The synergic and antagonistic effects of the four substrates on hydrogen yield,substrate conversion efficiency and pH were evaluated.The results showed that the optimal proportion of food waste,cattle manure,potato pulp and pig manure were 61.6%,38.4%,0,and 0,respectively.Under the optimal condition,hydrogen yield of 21.0 mL/g VS with VS reduction of 29.4%and pH of 5 could be obtained.The interaction between food waste and cattle manure had strongest synergistic effects.Hydrogen was mainly produced by acetic-butyric metabolic pathway,and ammonification of protein played an important role in the maintenance of pH.

How to enhance agricultural plastic waste management in China?Insights from public participation

Agricultural plastics play a pivotal role in agricultural production.However,due to expensive costs,agricultural plastic waste management(APWM)encounters a vast funding gap.As one of the crucial stakeholders,the public deserves to make appropriate efforts for APWM.Accordingly,identifying whether the public is willing to pay for APWM and clarifying the decisions’driving pathways to explore initiatives for promoting their payment intentions are essential to address the dilemma confronting APWM.To this end,by applying the extended theory of planned behavior(TPB),the study conducted an empirical analysis based on 1,288 residents from four provinces(autonomous regions)of northern China.Results illustrate that:1)respondents hold generally positive and relatively strong payment willingness towards APWM;2)respondents’attitude(AT),subjective norm(SN),and perceived behavioral control(PBC)are positively correlated with their payment intentions(INT);3)environmental cognition(EC)and environmental emotion(EE)positively moderate the relationships between AT and INT,and between SN and INT,posing significant indirect impacts on INT.The study’s implications extend to informing government policies,suggesting that multi-entity cooperation,specifically public payment for APWM,can enhance agricultural non-point waste management.

Bioconversion of low quality lignocellulosic agricultural waste into edible protein by Pleurotus sajor-caju(Fr.) Singer

Pleurotus sajor-caju (Fr.) Singer was cultivated on selected agro wastes viz. cotton stalks, groundnut haulms, soybean straw, pigeon pea stalks; leaves; wheat straw, alone or in combinations. Cotton stalks, pigeon pea stalks; wheat straw alone or in combination were found to be more suitable than groundnut haulms; soybean straw for the cultivation. Organic supplements such as groundnut oilseed cake, gram powder; rice bran not only affected growth parameters but also increased yields. Thus bioconversion of lignocellulosic biomass by P. sajor-caju offers a promising way to convert low quality biomass into an improved human food.

Stable Control of Influence Factor during Two-phase Anaerobic Digestion for Agricultural Organic Waste

Two-phase anaerobic digestion process is influenced by acid control for hydrogen production, reaction temperature, substrate detention time, sludge activity, and granular formation. Al of these technological parameters are directly related to success or failure of the system operation and treatment effect.

Solid State Reaction Yielding a Mineral Utilizing Silica Obtained from an Agricultural Waste

Wollastonite, a mineral of wide industrial applications was synthesised from rice husk ash silica and limestone. A number of raw batches consisting of these starting materials, in 1:1 molar ratio, were heat treated to produce it through solid state reaction from 900℃ to 1300℃. The conducted reaction was monitored by XRD step by step. Amount of Wollastonite formed at every temperature was also studied to some extent. Analyses of the obtained data indicated that the target mineral formation was quite effective and almost proportional to a rise in temperature up to 1200℃. The results from both, XRD and chemical analysis were found in fair agreement with one another

Hexavalent Chromium Adsorption from Aqueous Solution by Agricultural Waste Materials

Abilities of agricultural waste materials (walnut shell-WS, rice husk-RH, and peanut hull-PH) were tested as adsorbents for the adsorption of Cr(Ⅵ) from aqueous solution. Batch adsorption experiments were carried out to study the adsorption kinetics mechanism of Cr(Ⅵ) effect of adsorbent dosage, pH, contact time, and temperature. The best results are obtained at 15g/L adsorbent concentration, 60min contact time, 298K temperature, and 50mg/L adsorbate initial concentration at pH 2. The adsorption isotherms, using initial concentrations of Cr(Ⅵ) between 10 and 500mg/L for the Cr(Ⅵ) removal, show the maximum metal uptake capacities of adsorbent were 10.48, 6.71, and 8.54mg/g for WS, RH, and PH, respectively. And the adsorption data fitted well to the Langmuir adsorption isotherm for WS, RH, and PH with correlation coefficients of 0.9862, 0.9723, and 0.9714, respectively. Moreover, the FTIR analysis of WS, RH, and PH before and after adsorption of Cr(Ⅵ) suggested that Cr ions were combined to some functional groups of compounds contained in these materials.

The Energy Consumption of Heatingin the Northeast Rural Area of China from the Perspective of the Kang and Agricultural Waste

In China, the heating energy consumption patterns of rural housing are changing due to economic development. This study investigated domestic heating in rural areas of Dalian, a city in northeast China. In rural areas of the country, heating devices such as coal boiler, radiator, and/ or air-conditioner are typically used. The Kang, as the main heating system, has been used together with other heating methods for a long time in detached houses, one-story buildings, and quadrangles. Use of the Kang in collective housing is no longer observed. In addition to coal, agricultural wastes have been used to fuel the Kang; the associated CO2 emissions with agricultural fuels are lower than from other heating equipment. Even when a combination of the Kang and other equipment is used, with agricultural waste as fuel, CO2 emissions remain relatively low.

Chemicals,Energy,and Biomaterials from Agricultural Waste Resources in South China

Owing to its subtropical or tropical environment and climate,South China is home to unique agricultural crops such as sugar cane,pineapple,banana,cassava,and rice,which generate a large amount of lignocellulosic agricultural wastes during agricultural as well as associated industrial processing.The efficient utilization of these wastes will have a significant impact on the economy and sustainable development of South China.This paper reviews the research investigations conducted both in China and elsewhere on the conversion of wastes from these subtropical or tropical agricultural crops into useful chemicals,energy,and biomaterials.The goal of this paper is to promote and summarize the extensive investigations on these agricultural wastes for the development of biorefinery.

Recent Advance on Torrefaction Valorization and Application of Biochar from Agricultural Waste for Soil Remediation

With the increase of global proportion of soil pollution and the number of areas at risk,researchers have sought to develop various pathways to repair or relieve the pollutants in soil.Among them,biochar represents one multi-dimensional soil amendment which has got great deal of attention on its physicochemical properties towards the removal or mitigation of contaminants in soil.A variety of agricultural wastes like straw and manure prepared from different torrefaction process have been employed as feedstock for the production of biochar,which can be applied to the contaminated soil to facilitate the growing environment for crops,and to improve soil fertility and microbial environment.In addition,the utilization of biochar for soil remediation is also considered as a pro-cess of carbon sequestration.The purpose of this review is to summarize the latest research progress in torrefac-tion processes and mechanism of agricultural waste,the effects of different torrefaction methods on the formation and properties of biochar were explained,coupled with the effects of process parameters.Especially,the conver-sion and mechanisms of biochar prepared from agricultural wastes composed mainly with lignocellulosic material were discussed,and the characteristics of biochar prepared for improving soil physical and chemical character-istics,microbial community characteristics,nutrients,and the stability and relief of soil pollutants,especially heavy metals,are compared.Finally,this work discussed the application and future technical challenges of soil remediation based on agricultural waste derived biochar.

Current Situation and Suggestions for Energy Utilization of Agricultural Waste in Hubei Province

Energy utilization is high-value use pattern of agricultural waste, and is main development direction of agricultural biomass energy industry in China. Planting and breeding industry in Hubei Province occupies important position in whole country. Agricultural waste resources are rich, and it has huge potential for developing agriculturel biomass energy. By statistical data during 2000 -2011, we analyzed current situation and problem for energy utilization of agricultural waste in Hubei Province, and put forward several countermeasures and suggestions, vigorously promoting energy utilization of agricultural waste.

A Study on the Application of Agricultural Residue in Cultivation Substrate of Orchid

Five different substrates were prepared using oyster mushroom residue,rice straw,peat soil,pine bark,volcanic rock and perlite.Orchids(variety Chunjian)were cultivated on these five substrates with substrate being made from aseptic residue and straw as the control.The changes of physical and chemical properties of substrates and the growth of orchids were observed after three months.The results showed that the physical and chemical characters of the treatments and the control each had its own advantage,and there were no significant differences in the cultivation effects of all treatments.Therefore,the mushroom residue and decomposed rice straw are good substitutes for peat soil as soilless culture substrate in orchid cultivation.This research provides a scientific basis for the transformation of agricultural wastes into useful materials and can greatly stimulate the development of related industries.

Biogas Production from Organic Wastes to Promote Satisfying EU Requirements

Producing of renewable energy--as well in world as in national context--was necessitated by the synergistic effect of the climate change and the long term, continuous price rise of the fossil energy carriers. Main reasons for the spread of renewable energy sources are to increase the security of the energy supply or in optimal case, to realize the total energy independence. Furthermore, numerous studies demonstrate that production and also utilization of biofuels--including the organic waste-based fuels--are environmentally sustainable and have positive impact for the security of energy supply. This paper deals with production of biogas （from agricultural organic wastes） for energy. The production of biogas and the other biofuels will help you find the balance in agriculture because they can be generated from biomass, agricultural wastes and non-food plant material. In addition to the objective of saving emissions, EU biofuels policy aims to ensure the necessary energy and to decrease unemployment. So this paper would like to contribute to the EU requirements through the research. The producing system can be expansible by utilization of other organic material, so it is supported the efficient operation.

Valorization of Agricultural Waste: Theoretical Estimation and Experimental Biomethane Yield from Cashew Nut Hulls

Biomethane potential production from cashew nut hulls, an agricultural waste, was carried out using old and fresh hulls as substrates. Samples were taken from old hulls (around 8 years old) and fresh hulls produced in cashew scale transformation units at Bobo Dioulasso/Burkina Faso. Physicochemical parameters showed that cashew hulls can be a good candidate for anaerobic digestion. But high acidity, total phenols and lignin tenor could be a constraint for anaerobic bacteria. Theoretical biochemical methane potential showed high value of 666.937 CH4 L. (Kg VS)-1 and 526.206 CH4 L. (Kg VS)-1 for crushed fresh and powdered old hulls, respectively. Experimental biochemical methane potential showed significantly low potential of 1.982 CH4 L. (Kg VM)-1 and 46.840 CH4 L. (Kg VM)-1 for fresh and hold hulls, respectively. Pretreatment for optimization, chemical composition and co-digestion system must be expected for a better anaerobic digestion performance.

Assessment of Electric Power Generation via Water Hyacinths and Agricultural Waste

The importance and the necessary of researches on renewable energy have become a hot topic in recent years due to climate change and global warming. In addition, the fossil fuel reserves is facing rapid depletion on the earth. Currently, most researches have concentrated on producing biogas for heating, lighting, drying, cooking but lack in researching on electricity production because the possibility of producing biogas at households are common at small scale. Studying on alternative energy sources to replace traditional fuel for electric power generation brings new chances and great opportunities for development. This study presents an assessment electric power generation via water hyacinths and agricultural waste. In this paper, the evaluation electric power is generated by operating internal combustion engines which use biogas fuel to replace traditional fuel （diesel, gasoline）. The results of the studies were demonstrated by experiments on the renewable energy production system at Hoa An Biotechnology Research and Experimental Center of Cantho University.

An Overview of Sustainable Agricultural Waste Practices of West Texas

This article returns to the topic of sustainability. West Texas, mainly known for its cotton and cattle production, is facing problems related to the dispensation of agricultural waste produced by these operations. The article looks at the ways of handling agricultural waste and the opportunities of dispensing it in West Texas. Since between 30 - 40 percent of food produced in the US is not consumed, reduction of food waste is another sustainability problem that, when solved, would lead to the reduction of agricultural production and, in turn, the reduction of agricultural waste. Waste reduction management practices of large food chain stores in West Texas are discussed, with a final goal of bringing waste to a zero level. Public sources of sustainable agricultural and non-agricultural waste handling are also mentioned. This research adds to the previous knowledge on sustainability by discussing agricultural waste practices of a specific local area, i.e. West Texas.

Folic Acid-Functionalized Nanocrystalline Cellulose as a Renewable and Biocompatible Nanomaterial for Cancer-Targeting Nanoparticles

The study focuses on the development of biocompatible and stable FA-functionalized nanocrystalline cellulose(NCC)as a potential drug delivery system for targeting folate receptor-positive cancer cells.The FA-functionalized NCCs were synthesized through a series of chemical reactions,resulting in nanoparticles with favorable properties for biomedical applications.The microstructural analysis revealed that the functionalized NCCs maintained their rod-shaped morphology and displayed hydrodynamic diameters suitable for evading the mononuclear phagocytic system while being large enough to target tumor tissues.Importantly,these nanoparticles possessed a negative surface charge,enhancing their stability and repelling potential aggregation.The binding specificity of FA-functionalized NCCs to folate receptor-positive cancer cells was demonstrated through various assays.The free folic acid inhibition assay showed approximately 30%decrease in the binding of functionalized NCCs in the presence of just 5 mM free FA,confirming their selectivity for folate receptor-positive cells.Confocal microscopy further validated this specificity,as only cancer cells displayed significant binding of functionalized NCCs.Crucially,biocompatibility tests revealed that both NCCs and FA-functionalized NCCs had minimal effects on red blood cells,and they did not induce erythrocyte aggregation.Furthermore,cell viability assays demonstrated functionalized NCCs have selective cytotoxicity against colorectal cancer cells HT-29 and SW-620(68%–88%cell viability)while sparing noncancerous colon cells CCD-18Co(81%–97%cell viability).In summary,FA-functionalized NCCs exhibit promising characteristics for targeted drug delivery in cancer therapy.Their biocompatibility,stability,and selective cytotoxicity make them an attractive option for delivering therapeutic agents to folate receptor-positive cancer cells,potentially improving the effectiveness of cancer treatments while minimizing harm to healthy tissues.

Simulation and evaluation of tomato growth by AquaCrop model under different agricultural waste materials

This study aimed to enhance the utilization of agricultural waste and identify the most suitable agricultural waste materials for tomato cultivation. It utilized a locally modified substrate labeled as CK, along with five different groups of agricultural waste materials, designated as T1 (organic fertilizer: loessial soil: straw in a ratio of 4:5:1), T2 (organic fertilizer: loessial soil: straw: grains in a ratio of 3:5:1:1), T3 (organic fertilizer: loessial soil: straw: grains in a ratio of 2:5:1:2), T4 (organic fertilizer:loessial soil:straw:grains in a ratio of 1:5:1:3), and T5 ( loessial soil:straw:grains in a ratio of 5:1:4), the AquaCrop model was employed to validate soil water content and tomato growth and yield under these treatments. Furthermore, a multi-objective genetic algorithm was employed to determine the optimal agricultural waste materials that would ensure maximum tomato yield, water use efficiency (WUE), partial factor productivity of fertilizer (PFP) and sugar-acid ratio. The results indicated that the AquaCrop model reasonably simulated volumetric soil water content, tomato canopy cover, and biomass, with root mean square error (RMSE) ranges of 20.0-69.4 mm, 15.2%-25.1%, and 1.093-3.469 t/hm2, respectively. The CK group exhibited an R-squared (R2) value of 0.63 for volumetric soil water contents, while the ratio scenarios showed R2 values exceeding 0.80. The multi-objective genetic optimization algorithm identified T5 as the optimal ratio scenario, resulting in maximum tomato yield, WUE, PFP, and quality. This study offers a theoretical foundation for the efficient utilization of agricultural wastes and the production of high-quality fruits and vegetables.