Enhanced degradation of Acid Red 73 by using cellulose-based hydrogel coated Fe 3 O 4 nanocomposite as a Fenton-like catalyst.

Carboxymethyl cellulose-based hydrogel coated Fe ₃ O ₄ magnetic nanoparticles were prepared using a coprecipitation combining graft copolymerization method, and characterized by various techniques to study their structure-property relationships. The nanocomposite was used as a heterogeneous Fenton-like catalyst for Acid Red 73 degradation. The effects of several key parameters, solution pH, H ₂ O ₂ concentration, catalyst dosage, and temperature of the reaction medium on the pseudo-first-order kinetics of dye degradation was evaluated. The results showed that the nanocomposite catalyst were highly effective in activating H ₂ O ₂ to produce reactive radicals for dye degradation, achieving complete decomposition under optimal conditions of 300 min at 25 °C and pH 3.5 with 100 mM H ₂ O ₂ and 200 mg·L ^-1 catalyst. The complexing hydrogel-Fe ²⁺ /Fe ³⁺ were the key factors that speed up the redox cycling between Fe ²⁺ and Fe ³⁺ species, thus accelerate the fast degradation rate of target pollutants. Scavenging experiments and electron paramagnetic resonance analyses revealed that Acid Red 73 was decomposed mainly by the attack of •OH radicals. Besides, reusability of the prepared nanocatalyst was also tested.
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