Synthesis, characterization of chitosan-trithiocyanuric and its removal mechanism of Cr(VI) and Pb(II) from wastewater

• Published in: Chemical engineering science 2023-11, Vol.281, p.119144, Article 119144
• Main Authors: Wang, Wen, Qi, Liqiang, Han, Song, Yuan, Hejin
• Format: Article
• Language: English
• Subjects: Adsorption mechanism; Chitosan; Heavy metal ions; Response surface methodology; Trithiocyanuric acid
• ISSN: 0009-2509
• DOI: 10.1016/j.ces.2023.119144

[Display omitted] •A novel method for synthesizing chitosan-trithiocyanuric (CS@TMT) was proposed.•The Cr(VI) and Pb(II) adsorption capacity of CS@TMT reached 194.76 and 101.39 mg/g.•Higher acid and base resistance and reusability of CS@TMT was confirmed.•The mechanisms of the adsorption system at the solid–liquid interface were explored. A new chitosan-trithiocyanuric composite (CS@TMT) was synthesized by graft copolymerization using chloroacetyl chloride as the cross-linking agent. Using response surface analysis, the optimal conditions for the synthesis of CS@TMT were determined as: chloroacetyl chloride concentration of 2.0 mol/L, trithiocyanuric acid (TMT) addition of 7.0 g, and reaction temperature of 70 °C. The successful preparation of CS@TMT was confirmed FTIR spectrum, 13C NMR spectrum, SEM mapping, EDS, XRD and XPS. At ambient temperature (25 °C, pH=6.0, Catalyst dosage=1.0 g/L), the maximum Cr(VI) and Pb(II) adsorption amount of CS@TMT were 194.76 and 101.39 mg/g, respectively, compared to CS (97.15 and 69.76 mg/g). The Cr(VI) and Pb(II) removal process of CS@TMT was better fitted by the pseudo-second-order kinetic model and Langmuir model, and the adsorption process was spontaneous, endothermic and disordered. Under the reduction mechanism, 69.32% of Cr(VI) was reduced to Cr(III) by -SH and –OH group on CS@TMT.