ABSTRACT
In developing countries, due to rapid industrial growth and increases in human population, concerns over safe drinking water have become a critical issue. To provide safe drinking water, it is imperative to tackle both chemical and bacteriological contaminants. In most drinking water treatment plants, a combination of chemical coagulation and disinfection processes are adopted. The main disinfection procedures include ultraviolet (UV) irradiation, ozonolysis, chlorination, and electromagnetic radiation. It is well known that disinfection using chlorine produces carcinogenic by-products, while disinfection using ozone and UV irradiation is expensive. Thus, the important challenge faced by the water purification sector is a cost-effective and efficient method for providing safe water without endangering human health. To address this challenge, water treatment using biopolymeric materials is expected to play an increasingly important role in drinking water treatment. Chitosan is one of the abundantly available biopolymers after cellulose. It is biocompatible, renewable, biodegradable, nontoxic, possessing antibacterial properties, making it environmentally friendly. The main challenges in the use of chitosan include stability and selectivity toward various pollutants. A new class of nanocomposites are fabricated by combining biopolymeric materials such as chitosan with nanomaterials. To circumvent the problems associated with the selectivity and stability of chitosan, these nanocomposites can be tuned for their physicochemical and structural properties such as charge density, porosity, hydrophilicity, and thermal and mechanical stability, and introduce attractive functionalities such as antibacterial, photocatalytic, or adsorptive capabilities. These advanced nanocomposite biopolymers could be fabricated to meet specific water treatment applications. Thus, this chapter will focus on the recent
6.1 Introduction .......................................................................................................................... 166 6.2 Removal of Contaminants .................................................................................................... 167
6.2.1 Removal of Heavy Metals ........................................................................................ 167 6.2.1.1 Membranes ................................................................................................. 167 6.2.1.2 Magnetic Nanocomposites ......................................................................... 167 6.2.1.3 Others ......................................................................................................... 169
6.2.2 Removal of Fluoride, Nitrate, and Phosphate ........................................................... 169 6.2.3 Removal of Organic Pollutants and Dyes ................................................................. 169 6.2.4 Antimicrobial Property............................................................................................. 172 6.2.5 Concurrent Removal of Heavy Metal and Disinfection Control .............................. 173
6.3 Conclusions and Perspectives ............................................................................................... 174 References ...................................................................................................................................... 176
scientific and technological advances in the development of chitosan-based nanocomposites for water treatment.
