Heteroatom decorated polythiourethane sorbent for copper (II) extraction in wastewater treatment

Abstract

Copper ions in wastewater present substantial environmental hazards, toxic to aquatic species and prone to bioaccumulation. Addressing this, we present a novel cross-linked polythiourethane (C-PTU) as a promising chelating adsorbent for the effective removal of copper ions from wastewater. A new monomer, 5-(2,2,2-trifluoroacetamide) benzene-1,3-bis(carbonyl) isothiocyanate (TFA-ITC), was synthesized and further condensed with a 1,4-butane diol to produce a trifluoroacetamide functionalized polythiourethane (TFA-PTU) and subsequently generating amine functionalized polythiourethane (A-PTU). The cross-linking reaction was carried out through amino groups present on the polymer backbone with terephthaloyl chloride, resulting in the formation of C-PTU. The monomer and polymers underwent characterization using Fourier transform infrared, 1H, and 13C nuclear magnetic resonance spectroscopy, with X-ray diffraction analyzing the resin's chain alignment. Thermogravimetric and differential scanning calorimetry assessed C-PTU's thermal properties. The adsorption process for Cu(II) ions was studied using atomic absorption spectroscopy, optimizing conditions for maximal uptake. Results revealed that C-PTU exhibited a significant adsorption capacity for Cu(II) ions, reaching 67% after a 2 h contact time, with optimal adsorption occurring at pH 6. The Langmuir adsorption isotherm described the sorption mechanism, indicating favorable monolayer cation adsorption via coordination with donor sites on C-PTU. This research presents a viable solution for copper ion contamination in wastewater, illustrating C-PTU as an efficient, environmentally friendly adsorbent, marking progress toward cleaner water resources.