Adsorption dynamics of Congo red dye removal using ZnO functionalized high silica zeolitic particles

Abstract The present study focusses on the adsorption properties of zinc oxide (ZnO) in the form of nanoflakes on the surface of zeolite for the removal of Congo red (CR) dye. The purpose is to study the modification of adsorbent for improved adsorptive and photocatalytic performance. The morphology and structure of synthesized composite has been characterized by Scanning electron microscopy, Transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy and its performance towards adsorption and photodecomposition of CR has been evaluated. Adsorption dynamics as studied by time variation and concentration variation indicates that the adsorption data follows pseudo second order kinetics and Langmuir isotherm model with a maximum adsorption capacity of 161.3 mg/g, thus indicating homogeneous physiochemical adsorption of CR dye on the adsorbent surface. The synthesized composite is easily regenerable and reusable and is capable of removing CR dye from the polluted water up to 90% (for 5 regeneration cycles) and hence proves to be highly efficient and viable material for the water purification industries.