Functionalization of SBA-15 by dithiooxamide towards removal of Co (II) ions from real samples: Isotherm, thermodynamic and kinetic studies.

• SBA-15 was modified by dithiooxamide ligand using a simple method. • The dithiooxamide/SDS/SBA-15 nanocomposite is selective towards removal of cobalt (ll). • The surface of synthesized nanocomposite was investigated by TEM, BET, CHNS and TGA analyses. • The Freundlich isotherm showed better results than the Langmuir isotherm. • The negative variations of ΔG and the positive variations of ΔH was found for Co (II) adsorption. In this study, mesoporous SBA-15 was functionalized by dithiooxamide ligand through sodium dodecyl sulfate as intermediate. The obtained nanocomposite was considered as a strong adsorbent towards selective removal of the cobalt (II) ions from the industrial wastewater samples. Transmission Electron Microscopy (TEM) analysis, Brunauer-Emmett-Teller (BET) analysis, elemental CHNS (carbon, hydrogen, nitrogen, and sulfur) analysis, and thermo-gravimetric analysis (TGA) were used for characterization, particle size determination, confirming the presence of the used ligand, and measuring the nanocomposite stability, respectively. Effective parameters on the removal of the cobalt (II) ions such as pH, adsorbent dosage, concentration, and contact time have been evaluated. Results showed that the Freundlich isotherm has a bit better correlation coefficient compared to Langmuir isotherm (0.96 versus 0.94, respectively). The maximum amount of Co (II) ions adsorption on 1 g of nanocomposite (q m) is calculated to be 2500 mg/g that points to the excellent adsorption. Kinetic analyses were conducted using pseudo-first and second-order models and the regression results showed that the pseudo-second-order model is more accurate for the study of the cobalt adsorption due to the higher correlation coefficient (0.99 versus 0.83) compared to the pseudo-first-order model. The result of the present study points that the suggested nanocomposite can be positively used in treating industrial effluents containing cobalt ions. [ABSTRACT FROM AUTHOR]