Preparation, characterization and evaluation of nano manganese dioxide coated on alumina as a new adsorbent for the effective removal of phenol from aqueous samples

An effective sorbent nano manganese dioxide coated on alumina (NMO/Al) nanocomposite, as an economical adsorbent, was prepared in the present study. To this end, morphological, chemical, and surface characteristics of NMO/Al were determined through various techniques. The NMO/Al nanocomposite could be thus separated effortlessly from water samples using a filter paper and then, the removal of phenol from the wastewater samples was evaluated. Accordingly, various empirical parameters affecting this removal including pH, ionic strength, time, temperature, and phenol concentration were examined. In order to investigate the adsorption equilibrium, Langmuir, Freundlich, and Temkin equations were utilized. The Langmuir adsorption model had a higher correlation coefficient (R2) indicating better fit to the adsorption characteristics. Various kinetic models were employed to evaluate the adsorption kinetics of phenol on the NMO/Al nanocomposite. Based on the results, the Elovich model exhibited the best fit with a sorption capacity of 21.34 mg g?1. Additionally, the adsorbed phenol was desorbed from the NMO/Al surface by using ethanol with high efficiency, and then the NMO/Al nanocomposite was used again to remove phenol. The results showed that the NMO/Al nanocomposite could be reused for more than five cycles. Based on the findings, the phenol adsorption process from wastewater using NMO/Al nanocomposite is considered an efficient adsorption approach in a large-scale adsorption system.