Absorption of cadmium (II) via sulfur-chelating based cellulose: Characterization, isotherm models and their error analysis

Abstract

Sulfur-chelating based cellulose was produced successfully through alkali-pretreatment, etherification-substitution, amination-crosslinking and sulfurate-reaction. Further, its physico-chemical properties were characterized thoroughly, and several impact factors, i.e. adsorbent dosage, pH, co-existing ions, temperature and contact time were discussed in details. Particularly, the linear and non-linear isotherm models were used to determine the best-fitting one with the verification of 8 error functions. As a result, the adsorbent had more excellent adsorption capacity of 54.71 mg g−1 at the optimal conditions, i.e. dosage of 4 g L−1; 5.1 of pH value (50 mL of solution), 298 K of temperature, at least 180 min of contact time, and 5 cyclical regeneration of the adsorbent with 0.1 g L−1 ethylenediaminetetraacetic. The Fritz-Schlünder as 4-parameter isotherm model gave the best correlation of the experimental data. Moreover, a complex formation between Cd (II) and the CS, NH2 and NH groups was confirmed as the dominant chemical adsorption interactions.