Preparation Of Silver Nanoparticles Loaded Magnetic Biochar-Polydopamine Composites As Catalyst For Efficient Catalytic Reduction Of Organic Dyes

With the rapid development of industry,many organic pollutants are unintentionally released into the water body,especially the discharge of dye wastewater cause serious damage to the water environment and the ecological environment.In order to treat contaminated water bodies,many methods have been researched and developed,and the catalytic reduction for organic dyes using a catalyst has been strongly promoted.In order to explore efficient,economical,and environmentally friendly catalysts,Ag nanoparticles loaded on polydopamine coated magnetic biochar?MC-PDA-Ag?catalyst was prepared by in-situ reduction approach in this study.The surface morphology,elemental composition,and chemical structure of MC-PDA-Ag composites were characterized by the transmission electron microscopy?TEM?,the scanning electron microscope?SEM?,X-ray diffractometer?XRD?,X-ray photoelectron spectroscopy?XPS?,and vibrating sample magnetometer?VSM?,and the characterization results further confirmed the successful preparation of MC-PDA-Ag composite catalyst.Catalytic reduction tests confirmed that MC-PDA-Ag catalyst exhibited excellent catalytic performance on the model dyes?MB,RhB,and MO?in the presence of NaBH₄,but the catalytic effects of each model dye were different.At the same time,the adsorption performance of three composites on MB dyes was compared in the absence of reducing agent,and it was proved that the adsorption performance of MC-PDA-Ag was not as good as its catalytic performance.In addition,MC-PDA-Ag was compared with other reported catalysts,and it was found that the MC-PDA-Ag catalyst has excellent catalytic performance.The reduction efficiency of MB exceeded 90%by MC-PDA-Ag even under different initial pH?3-11?and different NaNO₃ concentrations?0-0.5 M?within 5 min,indicating that the MC-PDA-Ag catalyst has potential strong universal adaptability in dye wastewater treatment.Furthermore,no significant decrease in catalytic ability was observed after 5recycles,and the catalyst can be separated by an external magnet,indicating that this as-prepared catalyst exhibited high reusability and easy separability.These results collectively suggest that MC-PDA-Ag composites can be used as an efficient catalyst for the reduction of organic dyes,and have great potential for application in wastewater treatment.