CuO-Fe2O3/calcium alginate-carboxymethylcellulose-chitosan as efficient nanocomposite beads for catalytic reduction of water pollutants

Abstract

This study involved the synthesis and catalytic activity testing of new nanocomposite beads (CuO-Fe₂O₃/CA-CMC-Cs) prepared by facile and environmentally friendly approach. CuO-Fe₂O₃ was prepared and applied for the catalytic reduction of 4-nitrophenol (4-NP). The results showed that CuO-Fe₂O₃ demonstrate high catalytic activity toward the reduction of 4-NP to 4-aminophenol (4-AP). Further, CuO-Fe₂O₃ were well-dispersed in the polymeric matrix of CA-CMC-Cs to prepare CuO-Fe₂O₃/CA-CMC-Cs beads via crosslinker agent (AlCl₃). CuO-Fe₂O₃/CA-CMC-Cs beads were also applied for the catalytic reduction of nitrophenol isomers (4-NP, 2-NP, and 2,6-DNP), organic dyes (methyl orange (MO), eosin yellow (EY)) and potassium hexacyanoferrate (K₃[Fe(CN)₆]). K₃[Fe(CN)₆] was found to be effectively reduced by the beads and was completed within 30 s. While the catalytic reduction of 4-NP, EY and MO were completed within 300, 240 and 180 s and the rate constants were discovered to be 1.16 × 10⁻² s⁻¹, 1.68 × 10⁻² s⁻¹ and 1.51 × 10⁻² s⁻¹, respectively. The CuO-Fe₂O₃/CA-CMC-Cs beads catalytic activity was enhanced utilizing 4-NP as a model molecule. The beads had good catalytic activity and may be reused up to three times before losing their effectiveness. Additionally, the ability of the CuO-Fe₂O₃/CA-CMC-Cs beads to reduce 4-NP and MO in real samples such as wastewater, orange juice and strawberry juice was investigated where the reduction percentage was 91.5 %–89.0 % in the real samples. The results demonstrated that the beads were more efficient for reduction of 4-NP and MO in milk, while, in juices required more time and had a lower reduction percentage.