Removal of hexavalent chromium Cr(VI) from aqueous solutions using cellulose-magnetite membrane CelMag-M

Abstract

The industries of leather-tanning, mining and textile dyeing, generate large amounts ofchromium-containing wastewater. Hexavalent Cr(VI) is highly poisonous and extremelymobile in the surface-water and groundwater in a broad pH range and therefore it hasbeen identified as a potentially carcinogenic substance. The aim of the presented workwas to develop cellulose-based membrane functionalized with magnetite, which couldbe used as an efficient adsorbent for the removal of hexavalent chromium Cr(VI) ionsfrom aqueous solutions. Cellulose-based filter (CF) was functionalized with magnetitein three-step process. In the first and second step CF surface was modified usingan ethanolic solution of (3-aminopropyl)triethoxysilane (APTES), anddiethylenetriaminepentaacetic acid dianhydride, respectively. The introduction of aminoand carboxylic groups provided successful precipitation of magnetite in the third step.The obtained cellulose-magnetite membrane (CelMag-M) was characterized by FTIRand SEM analysis. Adsorption of Cr(VI) onto CelMag-M was studied using batchadsorptiontest. Under optimum pH conditions, the maximum experimental adsorptioncapacity of CelMag-M for Cr(VI) was found to be 111.2 mg g–1. The adsorption processwas endothermic, the equilibrium adsorption data could be best fitted to the Langmuiradsorption isotherm model and kinetics was in agreement with the pseudo-second-orderrate equation.