FACILE ULTRASONIC-ASSISTED ZIF-67 SYNTHESIS AND USE IN PHENOL REMOVAL FROM AQUEOUS SOLUTIONS

Abstract

Recently, water-stable ZIF MOFs, a new material class with a very large surface area, have attracted attention for the removal of organic pollutants. This type of MOF's excellent adsorption capacities, large pore volumes, and recyclability performances stand out compared to many other adsorbents. In this work, the ZIF-67 structure, a cobalt-containing ZIF, was synthesized using the ultrasound-assisted solvothermal method, and its phenol adsorption performance was investigated. The characterization of the ZIF-67 structure was carried out by SEM-EDS, XRD, FTIR, and nitrogen adsorption analyses. Nitrogen adsorption data showed that ZIF-67 had microporosity, and the surface area calculated from the BET model was 1656 m2/g. To synthesize ZIF-67, optimization of phenol adsorption, one of the important pollutants in water, was investigated by response surface method (RSM) for initial phenol concentration, adsorbent concentration, pH, and temperature variables. At the operating levels determined by RSM, the most effective removal of 92.2% was obtained at 30°C, 1 g/L adsorbent concentration, 20 mg/L initial phenol concentration, and pH 6.5. The adsorption isotherm of phenol onto ZIF-67 was fit to the Langmuir model, which is a monolayer interaction. According to the Langmuir isotherm model, the maximum phenol adsorption capacity of ZIF-67 was determined as 303.0 mg/g.