Refinement of contaminated water by Cr(VI), As(V) and Hg(II) using N-donor ligands arranged on SBA-15 platform; batch and fixed-bed column methods

Abstract

SBA-15 particles bearing N-donor functionalities, ethylenediaminopropyl and ethylenediaminepropylesalicylaldimine ligands (SBA/En and SBA/EnSA, respectively), were prepared and their potentials for elimination of chromium(VI), arsenic(V) and mercury(II) ions from aqueous solutions through batch adsorption experiments were studied. The adsorption processes were investigated by studying the parameters affecting the adsorption process including pH of the aqueous solutions, contact time, adsorbent dose, initial concentration of the ions, and temperature. The isotherms of the adsorption process were studied and discussed in detail. The Langmuir isotherm predicted the maximum adsorption capacities of SBA/En and SBA/EnSA for Cr(VI), As(V) and Hg(II) to be 67.1, 41.5 and 6.3mgg−1 and 76.9, 43.5 and 8.3mgg−1, respectively. It was shown that, pseudo second-order model described well the kinetics of the processes. A part of this study concerned on the evaluation of the efficiency of SBA/EnSA for removal of Cr(VI), As(V) and Hg(II) from their ternary aqueous solutions in fixed-bed column method. The effect of parameters affecting this process such as sample and eluent flow rates, bed height, sample volume, type and concentration of the eluent used, for desorption of the studied ions, on the process were assessed and discussed. The applicability of the proposed methods was examined by using them for decontamination of water samples containing the target ions.