Hemp-derived Activated Carbon Supported Zero-valent Iron as a Heterogeneous Fenton Catalyst for the Treatment of Pulping Effluent

Hemp fiber was applied to prepare activated carbon by phosphoric acid activation at a carbonization temperature of 400 degrees C. Then, zero-valent iron particles were immobilized onto the surface of hemp-derived AC (HAC), and the composites (ZVI@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 the catalyst were investigated. Results showed that ZVI particles were well-distributed on the surface of HAC without aggregation. Both HAC and ZVI@HAC had a microporous structure. With the loading of ZVI, the catalysts were endowed with magnetism and more active sites. Under the optimal conditions (3.0 initial pH, 35 mmol/L H2O2, and 3.0 g/L 2-ZVI@HAC), the chemical oxygen demand (COD) removal rate reached 87.74%. This work illustrated the feasibility of HAC as a carrier of ZVI and the ZVI@HAC was an effective heterogeneous Fenton catalyst.