Modelling and Optimization of As(III) Adsorption onto Thiol‐Functionalized Bentonite from Aqueous Solutions Using Response Surface Methodology Approach

Abstract

The aim of the present work was to investigate thiol‐functionalized bentonite (TFB) as a novel adsorbent for the adsorption of As(III) from aqueous environments and to determine optimal adsorption conditions. The response surface methodology (RSM) was applied to analyze the most significant variables for adsorption including initial pH, temperature (°C, T), initial As(III) concentration (mgL−1, Co), adsorbent dosage (g, m) and contact time (min., t). The optimum adsorption conditions according to the RSM were found to be 5.98, 42.87 °C, 31.02 mgL−1, 0.33 g and 127.48 min for initial pH, T, Co, m and t, respectively. Under these conditions obtained by the model, the maximum percentage of As(III) adsorption and adsorption capacity were found to be 91.01% and 8.56 mgg−1, respectively. The kinetic studies showed that As(III) adsorption followed a pseudo‐second‐order kinetic model and the rate was controlled by both intraparticle and film diffusion. Experimental data were compared with linear isotherm models and it was found that the adsorption data has better fit to the Langmuir isotherm model. Furthermore, the thermodynamic studies showed that the adsorption of As(III) was endothermic, possible and natural. Based on all these conclusions, it can be said that TFB has high potential for As(III) removal from aqueous environments.

Removal of dissolved glyphosate from waters by adsorption under the influence of metals

“…the process is adaptable to different applications, relatively selective for dissolved glyphosate, and sorbents are regarded as potentially non-hazardous to handle [41]. This makes adsorption an effective technique in glyphosate removal applications; coupled with the possibility of regenerating spent adsorbents economical [42].…”

“…Boyd et al [227] [39,40]. Adsorption distinguish it from other removal technologies as a non-hazardous, environmentally friendly [41], economical, flexible(in design), highly selective and efficient technique and at the same time the adsorbents can be regenerated [42]. Furthermore, incorporation of an adsorbent is convenient to be combined with the existing facilities to deal with the urgent problematic water sources.…”