Kinetic studies of adsorption on biochar from aqueous solutions

Abstract

The addition of biochar to soil in grasslands and cultivated areas has emerged as a promising way of mitigating global warming. Porous carbon, such as biochar and activated carbon, has been widely used as an adsorbent for gaseous and liquid phases. In recent years, there has also been a growing interest in investigating the adsorption activity of biochar. This review summarizes kinetic models to evaluate the adsorption performance by measuring the amount adsorbed as a function of time. Key kinetic models such as pseudo-first order, pseudo-second order, Elovich, and intraparticle diffusion are presented, and their uses reported in the literature are stated. Using these models, we have investigated phosphate adsorption on a Ca-loaded rice husk biochar prepared by carbonizing rice husk immersed in a CaCl₂ solution at 1000 °C and discuss the results.