Targeted reclaiming cationic dyes from dyeing wastewater with a dithiocarbamate-functionalized material through selective adsorption and efficient desorption

In this work, we applied a novel dithiocarbamate-grafted star-like polymer for efficient reclamation of cationic dyes. This material is highly selective towards cationic dyes and almost completely rejective to anionic dyes. The adsorption kinetics, isotherms, and thermodynamics were systematically investigated to analyze the adsorption behavior of cationic dyes onto the material. As compared with other reported adsorbents, this cheap and facilely-prepared material has exceptional adsorption capacities for industrial cationic dyes, e.g., methylene blue (MB, 2624 mg/g), crystal violet (CV, 2553 mg/g), basic fuchsin (BF, 1729 mg/g), and methylene violet 3RAX (MV, 1239 mg/g), being 5–11 times of that reported in literatures. Based on the effects of pH and ionic strength on adsorption, competitive adsorption of the cationic dyes, and FTIR characterization, mechanisms for the adsorption and desorption of cationic dyes were proposed. The adsorbed dyes can be recovered over 95% just by immersing into diluted HCl solution (0.01 M) for 10 min, thus avoiding organic solvent extraction. Over 98% of the adsorption capacity was maintained during consecutive reclamation operation. Due to the high selectivity, high adsorption capacity and the ease of efficient regeneration, this material is potentially applicable for targeted reclamation of cationic dyes from dyeing wastewater.