Adsorption properties of CuO/Sepiolite composite for malachite green and its antibacterial properties

Malachite green (MG) is a triphenylmethane dye resistant to degradation, possessing high toxicity, carcinogenicity, and mutagenicity, and co-existing bacterial contamination affects water safety. In this work, CuO-loaded sepiolite (CuO/Sep) nanocomposites were synthesized by an ammonia-driven deposition–precipitation method (ADP) to simultaneously remove MG and exhibit antibacterial activity. The nanocomposite with 10 wt% CuO had a specific surface area of 166.5 m 2 /g. The adsorption kinetics conformed to the pseudo-second-order kinetic model, and the equilibrium adsorption data could be described by the Langmuir model. At 295 K, the maximum monolayer adsorption capacity reached 809.6 mg/g, and the decolorization rate for an MG solution with an initial concentration of 50 mg/L reached 99%. The adsorption process involved a synergistic effect of physical and chemical adsorption, representing an endothermic reaction (ΔH = +55.36 kJ/mol). In addition, the composite exhibited good antibacterial activity, with antibacterial rates reaching 99.9% against Staphylococcus aureus and 97.5% against Escherichia coli . These results indicate that the synthesized CuO/Sep nanocomposite possesses both good MG adsorption capacity and broad-spectrum antimicrobial properties. Download: Download high-res image (277KB) Download: Download full-size image