Hemp derived activated carbon supported nanoscale zero–valent iron as a heterogeneous Fenton catalyst for the treatment of pulping effluent

Activated carbon (AC) and nanoscale zero–valent iron (nZVI) have been widely used in wastewater treatment, respectively, for the removal of organics. In this study, hemp fibers were applied to prepare AC by phosphoric acid activation at a carbonization temperature of 400°C. Then nZVI particles were immobilized onto the surface of hemp derived AC (HAC), and the composites (nZVI@HAC) were used as heterogeneous catalysts for Fenton–like treatment of pulping effluent. The as–prepared catalysts were characterized. The optimum conditions for Fenton–like reaction and the reusability of catalyst were investigated. Results showed that nZVI particles were well distributed on the surface of HAC without aggregation. Both HAC and nZVI@HAC have microporous structure. With the loading of nZVI, the catalysts were endowed with magnetism and more active sites. Under the optimal conditions (initial pH 3.0, H2O2 35 mmol/L, 2–nZVI@HAC 3.0 g/L), COD removal rate reached 87.74% of the highest. This work illustrated that the feasibility of HAC as a carrier of nZVI, and nZVI@HAC was an effective heterogeneous Fenton catalyst.