Effect of pH on Adsorption of Amoxycillin Trihydrate using Activated Charcoal from Maerua Decumbens

Abstract

Most pharmaceutical wastewaters contain amoxycillin trihydrate in trace or significant amounts. These compounds are toxic to aquatic life; and by extension to humans. Adsorption is one of the successful methods used to remove these pollutants from water. However, most pharmaceutical effluents occur in a wide range of pH which is a key parameter of adsorption process. This study aimed at evaluating the most feasible pH value for optimized adsorption of amoxycillin trihydrate using Maerua decumbens activated charcoal. M. decumbens charcoal and activated charcoal were prepared and characterized for functional groups. 500ml of 5g/L amoxycillin trihydrate sorbate was then subjected to batch adsorption at 300rpm for 2 hours. The sorbent weight used was 2.25g for both normal and activated charcoal. Parallel studies were conducted at 200C and 250C at varying pH values from 2.0 to 10.0. The initial (Co) and final concentrations (Ct) were analyzed by spectroscopic absorbance at 334.5nm. The activated sorbents had more functional groups compared to that of the normal M. decumbens. This led to more adsorption efficiency of up to 77% for the activated sorbent compared to 67% for the normal sorbent. Increase in pH values increased adsorption efficiency up to pH 8.0 after which adsorption efficiency decreased. The adsorption isotherms conducted revealed formation of both monolayers and multiple layers. These findings will greatly impact on wastewater purification strategies to eradicate water pollution globally.