Experimental study on the removal of phenol from wastewater using Ni-doped ZIF-8 adsorbent; Isotherm models and operating conditions

Phenols are considered serious contaminants because even at low concentrations, they are toxic and characteristics due to their toxic and carcinogenic properties. Removing the phenols from industrial effluents water before entering a stream is highly recommended Ni/ZIF-8 was used in a batch process to adsorb phenol from aqueous solutions at different temperatures. The operating conditions were considered as temperature, contact time, and initial pollutant concentration. The adsorption isotherms at different temperatures were determined based on three different models. For temperature range 25–40 oC, the best-fitting adsorption isotherm models were Freundlich > Langmiur > Temkin. It was found that the Langmuir model fits the experimental data well, with maximum adsorption capacities of 36.8 mg/g at 25, 25.9 mg/g at 40 and 22.4 mg/g at 60 °C. According to the results of thermodynamic analysis, the adsorption of phenol onto zeolite is physical and exothermic. The Ni/ZIF-8 adsorbent proved to be effective in removing phenol by adsorption.