Amino-Silane - Functionalized Palygorskite with as a Promising Adsorbent for Cr(III): Evaluation of the process variables

Abstract

Chromium represents a serious threat to living organisms and ecological system. Thus, this removal from wastewater is an urgent concern. The present study evaluates the ability of the functionalized clay mineral palygorskite (PalSIL) to remove the Cr(III) ion under different experimental conditions as a function of process variables: contact time, adsorbate concentration, amount of adsorbent and pH. Palygorskite (Pal) from Guadalupe (Piauí/Brazil) was treated with 3-aminopropyl-trimethoxy silane and characterized by. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, surface charge measurements (zeta potential) and textured properties (BET). The incorporation of amino-silane functional groups on the Pal surface resulted in maximum adsorption capacity of 21 mg g− 1 and the maximum removal percentage of 99%. Data on removal percentages were analyzed using statistical analysis to predict the most significant factors and interactions in this process. The results indicated that the adsorbate concentration, the amount of adsorbent and the pH significantly influenced the removal of Cr(III) ions. It is believed that the adsorption process occurred by the complexation of Cr(III) ions with the organo-functional amino group present at the surface of PalSIL. The kinetic parameters indicated that the fast mechanism of the adsorptive process is a phenomenon of chemical nature. The reaction equilibrium was quickly reached, demonstrating a readily available surface for adsorption. Thus, the present results indicate that PalSIL has the potential to remove Cr(III) ions and probably other potentially toxic elements from wastewater.