REMOVAL AND REGENERATION OF SE(IV) FROM AQUEOUS SOLUTION USING ADSORPTION ONTO A GEOMATERIAL RICH...

Excessive selenium (> 0.01 mg.L-1) is known to be harmful. It is primarily removed from wastewater using biological or chemical/physical techniques. The removal of selenium from water by adsorption onto raw and modified geomaterial (Zn-clay-rich material), which has not yet been tested in selenium adsorption, will be described in this article. Various techniques, including XRD, ICP, FTIR, and SEM coupled with EDX, are used to characterise these materials before and after usage in adsorption. The efficacy of selenium adsorption was investigated by changing the time, pH, beginning solution concentration, and temperature. Se(IV) adsorption was shown to be quick, reaching equilibrium in less than 2 hours with superior sorbent performance. Low pH appears to promote Se(IV) adsorption. The Langmuir model was shown to better reflect the adsorption process than the pseudo-second order model for Se(IV). The modified material had a maximum amount of selenium adsorbed of 8.47 mg.g-1, while the raw material had 5.26 mg.g-1. The thermodynamic investigation of the effect of temperature on adsorption revealed that G° and H° had positive values, indicating that Se(IV) adsorption on the various materials used is a non-spontaneous and endothermic process. Various acids were used to study the desorption/regeneration process, and they appear to be the optimum desorption agents for selenium regeneration. The use of aqua regia resulted in an 89.11 percent rate of adsorbed selenium regeneration. On the other hand, these findings highlight the importance of modifying the material in order to establish a new support for selenium removal.

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