Production, characterization and evaluation of biochar from pod (Pisum sativum), leaf (Brassica oleracea) and peel (Citrus sinensis) wastes

Purpose Biochar has potential as a valuable tool for theagricultural industry with its unique ability to help build soilhealth, increase physical properties of soil, soil pH, organiccarbon content, conserve water and mitigate drought, reduceGHG emission, conserve nutrients, decrease fertilizer requirements,sequester carbon, increase crop productivity and serve asa most preferred habitat for microbes. In this study, three perishablebiomass wastes viz. Pea pod (Pisum sativum), cauliflowerleaves (Brassica oleracea) and orange peel wastes(Citrus sinensis) were carbonized and characterized for differentialapplication.Methods The biomass was subjected to carbonization atdifferent temperatures from 100 to 600 C for 1 h. Biomassand biochar samples were characterized for proximate (M,VM, FC, Ash), ultimate (CHNS-O), biochemical properties(Ce, He, Li), thermo gravimetric analysis, pH, EC and bulkdensity. The biochars were also analyzed through SEM andFTIR for identification of pore size and functional groups.Results The char yield was high in cauliflower leaf(30.16 %), followed by orange peel (25.54 %) and pea pod(21.154 %) at 300 C. The total organic carbon (11.61 %),total negative surface anions (4.25 mmol H eq/g C) andwater holding capacity (200 %) were high in pea pod biochar.The SEM images of biochar samples showed plane cleavagesurfaces with broken edges. The surface functional groups ofall the three biochar samples were hydroxyl, methyl, carboxylicand alkene groups.Conclusion The pea pod and cauliflower leaf biocharshowed higher values of organic carbon, total surfaceanions, water holding capacity and mineral content andperformed as best soil amendment than orange peel biochar.These biochar can be used as an effective medium forincreasing soil carbon, irrigation efficiency and efficientdisposal of agricultural waste-biomass.