Adsorption behavior investigation of Cellulose-Triazole-TiO2 bionanocomposite for removal of Hg+2 ion from aqueous solution

The cellulose-triazole-TiO2 bionanocomposite synthesized via click reaction and utilized as a nanobioadsorbent for removal of Hg+2 ions from aqueous solution by batch technique. The adsorption parameters such as pH, contact time, adsorbent dosage, temperature, initial metal ions concentration and the regenerability of Cell.Com were investigated. The optimized adsorption conditions were found to be at pH 7, contact time 45 min, adsorbent weight 0.01 g and initial metal ion concentration of 20 ppm at 25 ºC. The Langmuir, Freundlich and Temkin isotherm models were evaluated using adsorption experimental data. The high absorption capacity obtained from the Langmuir equation (Hg+2 = 133.3 mg g-1) is related to the synergistic effect of TiO2, triazole ring and cellulose moieties in the structure of Cell.Com. Among the pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models, the experimental data was best fitted with the pseudo-second order model. Thermodynamic parameters indicated a spontaneous and endothermic adsorption process. The Cell.Com adsorption behavior represents that a monolayer chemical adsorption is the rate-determining step. The adsorption-desorption process for Cell.Com was performed in HCl solution at least 3 cycles without significant loss of the adsorption capability.