Dye removal using keggin polyoxometalates assisted ultrafi ltration: characterization and UV visible study

Abstract

To improve dye retention, there is a concurrent interest in the development and optimization of an alternative and promising method for the dye recovery in aqueous solutions. In this regard, considerable attention was paid to the polyoxometalates (POMs) assisted ultrafi ltration (POMAUF). The aim of the present study is to eliminate toluidine blue (TB) dye by ultrafi ltration membrane using keggin polyoxometalates (POMs) as complexing agents. In the fi rst step, the keggin polyoxometalates Kwere prepared. Then, the obtained powders were characterized by X-ray diffraction and infrared spectroscopies. Afterwards, the removal of toluidine blue (TB) using polyoxometalates assisted ultrafi ltration (POMAUF) was studied. Factors affecting the retention of dye and permeate fl ux such as transmembrane pressure, operating time, polyoxometalates concentration, ionic strength, surfactant and pH were investigated. All results of both compounds have been presented and discussed. The results reveal that the addition of POMs leads to an increase in dye retention from 11 to 95% for the PW 12 and to 98% for the PW 11 . The results of this work have thus suggested the promising enhancement of ultrafi ltration membrane selectivity for the dye removal using new complexing agents such as POMs in place of polyelectrolytes and surfactants.