Nanoscale zero-valent iron/biochar composite as an activator for Fenton-like removal of sulfamethazine

By Junmin Deng, Haoran Dong, Cong Zhang, Zhao Jiang, Yujun Cheng, Kunjie Hou, Lihua Zhang, Changzheng Fan. Separation and Purification Technology, 2018

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Abstract In this work, biochar-supported nanoscale zero-valent iron (nZVI/BC) was synthesized and used as an activator for Fenton-like removal of sulfamethazine (SMT). The possible removal mechanisms in the reaction system were proposed. nZVI was mainly responsible for H 2 O 2 decomposing to generate OH for the degradation of SMT, while BC played multiple roles, i.e., preventing nZVI aggregation, adsorbing SMT, activating H 2 O 2 , and alleviating nZVI passivation. The effects of various factors (i.e., the mass ratio of nZVI to BC, solution pH, H 2 O 2 concentration and nZVI/BC dosage) on SMT removal were evaluated. The highest removal efficiency (74.04%) of SMT (10 mg/L) was achieved at the optimal conditions (the mass ratio of nZVI and BC = 1:5, pH = 3, H 2 O 2  = 20 mM and nZVI/BC = 1.2 g/L). Additionally, the feasibility of recycling of nZVI/BC composites was examined. It was found that the removal efficiency of SMT decreased significantly from 74.04% to 53.28% and 38.02%, respectively, in the second and third run of experiments. X-ray diffraction analysis of the recycled composites demonstrated the gradual loss of Fe 0 content after each run of experiment, which resulted in the decrease of catalytic activity of nZVI/BC composites and thus the drop of SMT removal.

Subfields: Biomedical Engineering, Renewable Energy, Sustainability and the Environment, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/df31aa4848c4bb471c1b93de3e432b75099dbe7e