Water solution polishing of nitrate using potassium permanganate modified zeolite: Parametric experiments, kinetics and equilibrium analysis

Abstract

In the present study, adsorption potential of potassium permanganate (Hypermangan) modified zeolite was investigated for the removal of nitrate from synthetic wastewater. Effects of the most significant parameters (pH, adsorbent dose, nitrate concentration and contact time) were initially evaluated based on the percentage of nitrate removed from the water solutions. Over 90 % removal of 150 mg l-1 nitrate was achieved at an optimum pH of 5, adsorbent dose of 2g l-1 after a 60 min contact time. The chemical and morphological characterizations of Hypermangan modified zeolite (HMZ) were carried out by using scanning electron microscopy (SEM), fourier transform infrared (FT-IR), x-ray diffraction (XRD) and x-ray fluorescence (XRF) analysis methods. Kinetic evaluation indicated that the nitrate adsorption onto HMZ followed the pseudo-first-order model. The equilibrium data assessment illustrated the removal of nitrate by HMZ follows a Langmuir model which attains the maximum adsorption capacity 6.7 mg g-1.The mean free energy of adsorption was 0.15 kJ mol-1, which indicates the adsorption of nitrate onto HMZ, occurs through a physical mechanism.