Removal of methylene blue dye from aqueous solutions by adsorption technique using sodium alginate hybrid composites filled with SnS2

Abstract

Tin disulfide has been the focus of several investigations on its applicability in various fields due to its exceptional qualities. Furthermore, while there are several studies on its adsorption properties, there is a research gap on the effects of its incorporation into a biopolymer matrix on adsorption characteristics. In this study, experimental studies on the removal of methylene blue (MB) dye from wastewaters by eco-friendly, low-cost and adsorption method using SA/SnS2 composite adsorbents filled with SnS2 were carried out and the performances of the composite adsorbents were evaluated. The composite adsorbents were characterized by FTIR-ATR, SEM-EDX, and XRD. It was observed that the adsorption capacity increased from 219.17 +/- 5.36 mg/g to 399.65 +/- 5.89 mg/g with increasing mass percentage of SnS2 in the composition and the best adsorbent was SA/SnS2/30. From various isotherm models, Langmuir and Temkin models were found to be the most compatible models for the adsorption and qm value for SA/SnS2/30 composite adsorbent was determined as 532.52 +/- 6.67 mg/g at 318 K from Langmuir model. It was also observed that the adsorption capacity of SA/SnS2/30 composite adsorbent was about two times higher than that of SnS2 adsorbent. The adsorption process was found to follow an Elovich and quasi-second-order kinetic models. Thermodynamic parameters showed that the MB adsorption was endothermic (Delta Ho=11.37 +/- 0.09 kJ/mol) and spontaneous (Delta Go=-25.24 +/- 0.28kJ/mol at 298 K) for SA/SnS2/30. Considering all the results, SA/SnS2/30 composite adsorbent can be used as an environmentally friendly, biodegradable, sustainable, effective, and reusable adsorbent for MB dye removal from aqueous solutions.