A Mini-Review on Lead Ion Removal Using Polymeric Nanocomposite Membranes from Aqueous Solutions

The rapidly increasing global population and industrialisation are the main causes of the problem of water contamination. Issues with heavy metals are the main cause of this contamination. At least 20 metals are considered toxic and one of the most toxic is lead (Pb). Even though lead is being used in various industries, 86% of lead is remarkably used in battery industries, contributing to lead pollution. Water is utilised extensively during the battery-making process, particularly for washing battery parts for recycling. Hence, the process water becomes heavily contaminated, majorly with Pb compounds. Accordingly, treating Pb-containing effluent is mandatory for humanity and industrial survival. The conventional purification techniques were not sophisticated and resulted in waste and complex effluents harmful to the environment, demanding more advanced purification systems. A non-destructive separation, known as membrane separation, is a well-established technique for treating wastewater containing heavy metal ions and producing high-quality treated effluent. Polymeric membranes are of primary interest, as they can be easily modified and compatible with different materials like polymers and nanoadditives to improve membrane performance. The performance is primarily evaluated based on porosity, hydrophilicity, permeability, rejection capacity and anti-fouling nature. This study compiles research on polymer nanocomposite membranes for lead removal from the last five years.