Influence of pyrolysis conditions of modified corn cob bio-waste sorbents on adsorption mechanism of atrazine in contaminated water

Abstract

Pyrolysis is a major process in producing biochar sorbent from agriculture waste. The adsorption capability of biosorbents is greatly affected by the pyrolysis conditions. In this study, the adsorption interaction of atrazine and hydrochloric acid (HCl) modified corn cob bio-waste sorbents (CBS) was investigated as the function of the pyrolysis conditions, which are pyrolysis temperatures (400–600 °C) and residence times (2 to 6 h). The CBS characteristics, adsorption behaviour, and kinetics were determined. Pyrolysis conditions affected the specific surface area (SSA) and the total pore volume (TPV). The increasing ability of atrazine adsorption of CBS depended on SSA and TPV. The chemical interaction between atrazine and CBS was dominated by the H-bonding interaction. The maximum adsorption capacity of CBS was in the range of 11.31–19.58 mg/g. The sorption energy range of the CBS and atrazine interaction was 22.13–38.05 kJ/mol. The pseudo-second-order-model was the best fit describing the adsorption kinetics of atrazine on CBS. The rate-limiting step from the intra particle diffusion model has a high tendency to be the film diffusion. From this work, CBS has a high efficiency in atrazine adsorption and it can be an effective material with great potential for pollutant removal.