Modification of Thin Film Composite Membrane by Chitosan-Silver Particles to Improve Desalination and Anti-Biofouling Performance

The sources, leaching, remediation, and environmental concerns associated with groundwater salinity

Water resources management and sustainable development depend on the quality of groundwater as a major source of fresh water. As a result of rising water demand in emerging nations and overexploitation, groundwater quality has declined globally in many aquifers. One of the most significant elements that lower the quality of the groundwater is salinization. This review is to provide an overview of various materials that are used in the design and development of innovative chitosan-based nanocomposite polymeric membranes for desalination. Biodegradable, non-toxic, affordable, and easily available, with film-forming ability and poly-functionality, chitosan is an ideal material for a sustainable future. Membrane preparation for desalination using chitosan helps to provide antibacterial and antioxidant activities, great chelating capabilities, and strong adsorption capacity. In this research, we discuss a variety of concepts concerning the different sources of elevated salinity and available desalination methods. A comprehensive framework was also developed to understand the leaching and percolation of salt in groundwater, an essential component of managing risks and ensuring safety. Additionally, we explain the various remediation strategies for reducing groundwater's salt concentration and explore the best method for desalination specifically focused on chitosan.

Ultrathin Graphene Oxide-Based Nanocomposite Membranes for Water Purification

Two-dimensional graphene oxide (GO)-based lamellar membranes have been widely developed for desalination, water purification, gas separation, and pervaporation. However, membranes with a well-organized multilayer structure and controlled pore size remain a challenge. Herein, an easy and efficient method is used to fabricate MoO₂@GO and WO₃@GO nanocomposite membranes with controlled structure and interlayer spacing. Such membranes show good separation for salt and heavy metal ions due to the intensive stacking interaction and electrostatic attraction. The as-prepared composite membranes showed high rejection rates (˃70%) toward small metal ions such as sodium (Na⁺) and magnesium (Mg²⁺) ions. In addition, both membranes also showed high rejection rates ˃99% for nickel (Ni²⁺) and lead (Pb²⁺) ions with good water permeability of 275 ± 10 L m^-2 h^-1 bar^-1. We believe that our fabricated membranes will have a bright future in next generation desalination and water purification membranes.

A Review on Membrane Biofouling: Prediction, Characterization, and Mitigation

Water scarcity is an increasing problem on every continent, which instigated the search for novel ways to provide clean water suitable for human use; one such way is desalination. Desalination refers to the process of purifying salts and contaminants to produce water suitable for domestic and industrial applications. Due to the high costs and energy consumption associated with some desalination techniques, membrane-based technologies have emerged as a promising alternative water treatment, due to their high energy efficiency, operational simplicity, and lower cost. However, membrane fouling is a major challenge to membrane-based separation as it has detrimental effects on the membrane's performance and integrity. Based on the type of accumulated foulants, fouling can be classified into particulate, organic, inorganic, and biofouling. Biofouling is considered the most problematic among the four fouling categories. Therefore, proper characterization and prediction of biofouling are essential for creating efficient control and mitigation strategies to minimize the damage associated with biofouling. Moreover, the use of artificial intelligence (AI) in predicting membrane fouling has garnered a great deal of attention due to its adaptive capability and prediction accuracy. This paper presents an overview of the membrane biofouling mechanisms, characterization techniques, and predictive methods with a focus on AI-based techniques, and mitigation strategies.