Synthesis of metal organic frameworks (MOF-199) and it’s application for chromium (VI) adsorption from aqueous solution by experimental design approach

Abstract

The presence of heavy metals in streams arising from the discharge of industrial effluents into water bodies is one of the most important environmental issues because of their toxic nature. Chromium is one of the most widely utilized metals in today’s world, making it the most common longstanding environmental contaminant in natural water bodies. In the present study, response surface methodological optimization strategy using central composite design was used for the adsorption of Cr (VI) using metal organic framework (MOF-199) as adsorbent. Effect of various operating parameters such as initial metal concentration, adsorbent dosage and contact time was studied and optimized. From the statistical analysis of the experimental data, the optimum conditions for the maximum removal of metal ions was achieved at a concentration of 10 mg/L, adsorbent dosage of 10 mg and a contact time of 120 minutes. At these optimized conditions, the maximum percentage of Cr (VI) removal was found to be 84%. The adsorbent (MOF-199) was synthesized and characterized using PXRD, FTIR, BET, SEM/EDX and the amount of Cr (VI) adsorbed was measured using UV- spectrophotometer. Adsorption was fit to Langmuir model, the kinetics by pseudo‐second order. Gibbs free energy (ΔG°)at standard conditions shows that adsorption processes studied are spontaneous.