Carbon nanotube as catalyst support in wet air oxidation of water treatment

The Earth we live in, its habitability, that is, its ability to sustain life goes beyond billion years because of its natural means to recycle waste and clean itself. However, global industrialization, increased human population, and various human activities have resulted in excessive pollution, one of the most concerns being water pollution. Organic and inorganic wastes are the major contributors to water pollution. Wet air oxidation is a key technology in treating industrial and agricultural wastewater. It involves high-pressure and temperature reactions of oxidizable materials in wastewater with atmospheric or industrial synthesized oxygen. The application of heterogeneous or homogeneous catalysts is involved in catalyzing the reaction, with salts of iron, copper, and manganese frequently employed as homogeneous catalysts. Currently, various other technologies have been developed to mitigate water pollution. Among them is the use of nanomaterials with carbon nanotubes (CNTs) as support material. Due to their unique and tunable structural, physical, optical, and chemical properties, CNTs have demonstrated great potential for use in wastewater treatment. They have been used as components in various types of adsorbents based on organic and inorganic materials for pollutant removal from wastewater. This chapter provides an overview of the applications of CNT-based materials in wastewater treatment processes. It highlights the importance of CNT-based membranes in water purification as membrane filters for water disinfection, additives for antifouling, and aligned membranes for seawater desalination. It also dwelled on using CNT-based photocatalysts for organic pollutants removal and metal reduction, as well as electrocatalysts for organic pollutants removal from water.