Adsorption behavior of dyes from an aqueous solution onto composite magnetic lignin adsorbent

Magnetic lignosulfonate functional materials that were known to remove several types of dye from water effectively were prepared. The surface of an iron (II,III) oxide (Fe₃O₄) sample was coated with a layer of organic carbon, and magnetic lignosulfonate (FCS) was synthesised by a crosslinking agent. The morphology, structure, stability and magnetic properties of the materials were characterised by various testing methods. Under experimental conditions, the solution's acidity, alkalinity, contact time, temperature, desorption and dye concentration were measured. The experimental results show that the material reached the highest adsorption capacity at pH = 7. In addition, the adsorption data was similar to that of a single layer, Langmuir adsorption model. The maximum adsorption capacities were 198.24 mg g^-1 (Congo Red) and 192.51 mg g^-1 (Titan Yellow), respectively. Based on its desorption performance, the material had good recyclability. Therefore, these studies could be used in wastewater treatment. Hopefully, the proposed magnetic composites will inspire more scholars to investigate solutions to the problem of contaminated water resources.