Chapter 5 - Comparison of different nanoprocesses and industrial waste-based adsorbents such as red mud, steel slag, and fly ashes for treating wastewater nanomaterial contaminants

Abstract

Treatment of wastewater and contaminated water by nanomaterial-based treatment techniques has shown promising success for wastewater treatment processes and potable water management. However, other treatment processes using different industrial waste-based adsorbents such as red mud, steel slags, and fly ash have also shown great success to remove contaminants from wastewater. There are four types of nanomaterials that are widely used in nanotechnology for the treatment of wastewater and contaminated water. These are nanoadsorbents, nanocatalysts, nanomembranes, and integration of nanotechnology with biological processes. The nanomaterials that are used as nanoadsorbents to remove heavy metals from the wastewater include activated carbon, carbon nanotubes, grapheme, manganese oxide, zinc oxide, titanium oxide, magnesium oxide, and ferric oxides. The nanocatalysts such as photocatalyst, electrocatalyst, Fenton-based catalyst, and chemical oxidant are applied to successfully remove both organic and inorganic contaminants from wastewater. The nanomembranes such as carbon nanotube membranes, electrospun nanofibers, and hybrid nanomembranes can efficiently remove dyes, heavy metals, and foulants from wastewaters. The integrated technology combining nanotechnology and biological processes such as algal membrane bioreactor, anaerobic digestion, and microbial fuel cell is also currently used and under investigation for wastewater purification. Industrial wastes such as bauxite residue (red mud), steel slags, and fly ash can be used as potential active filter materials in constructed wetlands to remove heavy metals from wastewater. Furthermore, these waste materials can be utilized as soil amendments to reduce the environmental effect and immobilize pollutants. The chemical treatment of these wastes can produce coagulants and novel nanocomposite that are efficient for tertiary treatment of wastewaters.