Role of cellulose and lignin on biochar characteristics and removal of diazinon from biochar with a controlled chemical composition

In this study, the effects of carbohydrate and lignin content in biomass on the production of biochar were investigated, and the adsorption behaviors of diazinon on the biochar obtained from delignified oak were evaluated. The lignin content in biomass can be controlled by delignification. Biomass lignin content decreased and cellulose content increased with increasing delignification time, thereby increasing the crystallinity index of delignified oak. Although the biochar yield of the delignified oak decreased, its specific surface area (354.68–444.36 m2/g) and total pore volume (0.162–0.202 cm3/g) were higher than those of the biochar obtained from raw material (193.22 m2/g and 0.093 cm3/g). In the delignified oak, the specific surface area and total pore volume of biochar increased with increasing delignification time. Mesopores and micropores were more developed in the biochar obtained from the delignified oak than in the raw material. The removal efficiency of diazinon by biochar increased with increasing delignification time. Based on the Langmuir and Freundlich isotherms, diazinon adsorption to biochar was suitable for the Langmuir model.