Cu-Fe nanoparticles decorated rice hull/chitosan@FeAl2O4 to boosted peroxidase-like activity for catalytic degradation of antibiotics: Kinetics and mechanistic insights

Abstract

A series of derived magnetic porous carbon skeleton-coated Cu/Fe nanocomposites (CunFe1-n@CRH-x) were synthesized using chitosan-rice hull waste-hercynite by an injection molding and impression method, which is introduced as a “treating wastewater by waste residuals” for environmental-friendly remediation. Specifically, the CRH-x is a unique platform for the growth of uniformly dispersed metal oxides with high catalytic performance. After that, the morphological and structural features of post-synthesized nanocomposites were fully identified by applying alternative analytical and spectroscopic tools. The peroxidase-like activity of catalysts via electron transfer process between the simultaneously surface-activated H2O2 and target contaminants (e.g., tetracycline (TC), naproxen (NPX), ciprofloxacin (CIP), and paracetamol (PC)) were evaluated in detail. In the following, to find interrelationships between catalytic performance and structural characteristics, environmental parameters, ions interface, long-term stability, reusability, removal pathway, and universality of the system in various water sources were investigated in detail. The excellent peroxidase-like activity of Cu0.6Fe0.4@CRH-400 can be related to the high Brønsted acid intensity, small pore size, high surface area, and dual-synergy of Cu-Fe nanocatalyst and H2O2. The Cu0.6Fe0.4@CRH-400 can be boosted electron transfer via the dual redox cycle of Cu2+/Cu+/Cu2+ and Fe3+/Fe2+/Fe3+ under its core–shell scaffold, which promoted the generation and/or conversion of active species (•OH2, O2•-) to •OH. 98.20 % of TC, 93.90 % of NPX, 92.10 % of CIP and 100 % of PC were degraded through a rate constant (and TOC (%) removal) of 0.0838 min−1 (51.10 %), 0.0897 min−1 (46.5 %), 0.0737 min−1 (42.30 %), and 0.1168 min−1 (54.6) in Cu0.6Fe0.4 @CRH-400/H2O2 system, respectively, which confirmed that the remediation follows pseudo-1st-order kinetic model. Additionally, the low activation energy of 22.04 kJ/mol and favorable ΔH (−19.60 kJ/mol) of TC degradation confirmed the effectiveness of the catalytic system. Importantly, the reaction pathway was proposed and then predicted the acute toxicity (oral LD50) and mutagenicity of the degradation intermediates. The fairly high degree of mineralization, high anti-interferences, broad-spectrum remediation capacity, adaptability to predominant environmental conditions, and wide pH range (3.0–9.0) by Cu0.6Fe0.4 @CRH-400/H2O2 system in the various real water matrices further endorsed the superiority of the catalytic system.