Adsorption and desorption capacity of different metals influenced by biomass derived biochar

Abstract

By expanding the surface area and/or by other chemical reactions, soil additives such as biochar help retain nutrients in the soil. n this work, the effects of biochar on the adsorption and desorption of heavy metals and soil elements necessary for plant growth were investigated. To illustrate the adsorption of nutrients and heavy metals from solution on biochar, the Freundlich isotherm was employed. The rise in mineral nutrients, pH, and EC was linked to an increase in CEC with warmth. Because of its high CEC, biochar improves soil health and increases plant nutrient availability, which can boost agricultural yield when applied to the soil. In manure + biochar at 2.5 + 7.5 t/ha application rate the NH4+-N adsorption capacity was minimum in T7 (15.9 and 117.66) followed by T4 (17.6 and 130.24), T13 (18.7 and 138.38) and maximum in T10 (20.1 and 148.74) at 25 and 200 mg kg-1 level of added NH4+-N, respectively than control T1 (10.3 and 75.3). An increase in the rate of biochar application led to a favourable effect by increasing the NO3–N adsorption capability. The effect on P adsorption was more with biochar than manures. In manure + biochar at 2.5 + 7.5 t/ha application rate the Pb adsorption capacity was minimum in T7 (4.46 and 30.77) followed by T10 (4.71 and 32.49), T13 (5.16 and 35.60) and maximum in T4 (5.48 and 37.81) at 10 and 100 mg kg-1 level of added Pb, respectively than control T1 (1.86 and 12.83). Goat manure, FYM, vermicompost, and poultry manure had the greatest effects on desorption. The desorption of all heavy metals Cd, Pb, Zn, and As decreased as the rate of biochar application increased. Based on excess nutrients and heavy metals, this study supports the use of biochar to mitigate environmental concerns.