The Study of Citrullus colocynthis Shell Ash Efficiency in Phenol Removal from Synthetic Aqueous Solution

Abstract

Introduction and purpose: Phenol is one of the common pollutants found in many industrial effluents , which affects the environment and human health due to its special features like high toxicity and carcinogenic properties. The use of adsorbents is one of the most effective strategies for the  removal of phenol. In this study, we investigated the efficiency of Citrullus colocynthis shell ash as a natural adsorbent in phenol removal from aqueous solutions. Methods: This was an experimental study, where the effect of different variables such as the initial phenol concentrations (i.e., 10, 20, 50, 80, and 100 ppm), contact time (i.e., 2, 5, 10, and 30 min), adsorbent dose (i.e., 0.5, 1, 3, 5, 7, and 10 g/L) and pH (2-12) were studied. Then, the  adsorption process was described with Freundlich and Langmuir isotherms at controlled temperatures. Excel software was used for data analysis. Results: The results revealed that the highest removal rate of phenol was obtained at pH of 2 (79.8%), primary phenol concentration of 20 ppm (66.4%), adsorbent dose of 5 g/l (86.8%), and contact time of 10 minutes. Also, the correlation coefficients of isotherms (Freundlich and Langmuir) showed that phenol adsorption by Citrullus colocynthis shell ash had more accordance with the Freundlich model than the Langmuir model. Conclusion: We found that Citrullus colocynthis shell ash can be used as a lowcost and accessible adsorbent for phenol removal from aqueous solutions