The rapid increase in population and urbanization leads to the scarcity of water resources in the present era. Therefore, effective wastewater treatment is a prerequisite for a growing economy. Development and implementing the advanced treatment technologies of wastewater with high efficiency and low capital is difficult. In the recent advancements among various treatment processes, nanomaterial science has been attracting the attention of researchers. However, limited collective knowledge is available in this context. The chapter reviews the potential of nano catalysis's process, mechanism, and current drawbacks in treatment technologies. It explains the different nano catalysts that are widely utilized for the treatment and removal of organic and inorganic pollutants in water and wastewater and discusses the nano-based photocatalytic, nano-based electrocatalysis, nano-based Fenton catalysis and their efficiency in various removal of pollutants from wastewater.
TopIntroduction
Water is one of the most abundant natural resources available on the earth, but for human consumption, only about 1% of that resource is available (Grey, 2013; Adeleye et al., 2016). Due to the rising cost, growing populations and a variety of climatic conditions, it is estimated that over 1.1 billion people (WHO, 2015), lack the supply of adequate drinking water (Adeleye et al., 2016). The water supply chain is one of the significant challenges due to the continued contamination of freshwater resources by a variety of inorganic and organic pollutants (Schwarzenbach et al., 2006). The treatment of wastewater and drinking water can reduce (Xia et al., 2011), these concerns; however, the outdated methods of treatment are not competent enough to completely remove the emergent pollutants and meet the water quality standards.
Moreover, the current technologies of wastewater treatments have several downsides such as high-energy requirement, incomplete pollutant removal and generation of toxic sludge (Qu et al., 2012). The biological wastewater treatment is effective and widely applied, but these are usually sluggish, inadequate due to the presence of the non-biodegradable contaminants and yet cause toxicity to microorganisms due to the toxic pollutants (Reddy et al., 2017; Zelmanov et al., 2008). Physical processes like filtration can remove the contaminants by transmuting one phase to another but, produces highly concentrated sludge which is toxic and difficult to dispose of (Çatalkaya & Bali, 2003).
In the above context, there is a real necessity for more efficient and robust technologies for the treatment of municipal and industrial wastewaters which can be achieved either by the development of entirely new methods or by improving the existing processes through some interventions. Among the various developing technologies, the advancement in nanotechnology has proved a farfetched potential for the treatment of wastewater and various other environmental concerns (Burkhard et al., 2000; Parsons et al., 2006; Crini et al., 2007; Ferroudj et al., 2013).