A novel approach in remediation of diclofenac from environmental water samples using silver nanocomposite polymer inclusion membrane

Abstract

Diclofenac is an efficient anti-inflammatory drug used as an antipyretic and analgesia in human and animal medicine. As such they are indiscriminately consumed with or without the prescription of a physician which has led to usage above recommendation, wasted, and improper disposition; thus, has become persistently found in aqueous environment. As a result of their low solubility, they adhere strictly to biosolids during wastewater treatment which leads to incomplete removal of this contaminant by conventional wastewater treatment plants. Hence, the need for other water treatment technologies to remove this environmental stressor. Polymer inclusion membranes (PIMs) used in this study were impregnated with silver nanoparticles (AgNPs) and were investigated for the complete removal of DCF. Under optimum conditions, the best membrane's performance with 100 % transport efficiency was recorded at pH 3, with 5 % AgNPs. Further addition of AgNPs >5 % reduced the efficiency of the membranes in terms of water uptake capacity, ion-exchange capacity, permeability and transport efficiency. The stability/reusability was investigated over a 12-cyclic mass transfer. The stability of the membrane was evaluated based on the percentage mass loss and transport efficiency over the successive cycle. Thus, after the 7th cycle, about 15 % weight of the membrane was lost with a decline in transport efficiency. However, the nanocomposite PIM maintained stability with no mass losses or further decline in transport efficiency after the 7th cycle. Finally, the nanocomposite membrane was used to preconcentrate DCF from wastewater samples, and it recorded an enrichment factor between 23.5 and 24.8 and a transport efficiency between 94.1 and 99.2 %.