Rapid adsorption of acid dyes using Cu(II) thiourea modified cellulose complex

In the present work, the acid dyes namely, eriochrome cyanine R (ECR) and 2-(4-Sulfo phenyl azo)-1,8 dihydroxy-3,6 naphthalene disulfonic acid, trisodium salt (SPADNS) were effectively adsorbed by Cu(II)-thiourea modified cotton fibers (Cu(II)/Tu-MC) complex. FTIR, SEM, XPS analysis, thermogravimetric analysis, and potentiometric titration were utilized for characterization. The impact of the fundamental adsorption parameters was systematically investigated. The results reveal that the adsorption of ECR and SPADNS acid dyes occurs via a metal-coordination mechanism. Furthermore, the adsorption process follows the 2nd order kinetic model and Langmuir model adsorption isotherm. The Cu(II)/Tu-MC shows high adsorption capacities of 0.27 and 0.22 mmol/g for ECR and SPADNS, respectively. These findings indicate that the cationization of cellulose fibers with metal ions is a promising and efficient strategy toward enhancing the adsorption of acid dyes.