Facile synthesis of Fe and N co-coped biochar from low temperature pyrolysis of lignin waste for superefficient Th(IV)/U(VI) separation: Performance and mechanism
Lijun Guo, Xiaorong Lai, Liangqiong Peng, Jiheng Li, Wenhua Zhang, Bi Shi
Abstract
This study synthesized a nitrogen and iron co-doped biochar (Fe-N/BC) through a facile process of direct pyrolysis from lignin waste at a low temperature. The introduction of Fe and N can not only promote physical properties such as compact pores, high surface area , stable crystal, and magnetically recyclable ability, but also greatly enhance the electron transfer capacity of biochar surface through introducing electrophilic groups, for instance, C-N, pyrrolic N, C O, Fe 3+ , and C-C O. Moreover, 74.0 mg/g of U(VI) and 360.3 mg/g of Th(IV) was adsorbed by the optimal Fe-N/BC-200, and a high separation index (171147) was obtained. Fe-N/BC outperforms most of biochars from the point of adsorption capacity and cost consumption. Hence, this study reports an economically advantageous method for synthesizing Fe and N co-coped biochar with excellent separation capacity for U(VI)/Th(IV), making it a competitive alternate for other Fe and N co-coped biochar on industrial-scale.