The 12 chapters comprehensively cover the development and advances on emerging carbon-based nanocomposites for wastewater applications and discuss the following topics: The emerging carbon-based nanocomposites for remediation of heavy metals and organic pollutants from wastewater; Functional green carbon nanocomposites for heavy-metal treatment in water; Green nanocomposites and their applications in environmentally-friendly carbon nanomaterials; Carbon-based nanocomposites as heterogeneous catalysts for organic reactions in environment-friendly solvents; Carbonaceous nanomaterials for arsenic and chromium removal from waste water; Biochar-based adsorbents for the removal of organic pollutants from aqueous systems; Describes carbon nanomaterials based green nanocomposites; The removal of trihalomethanes from water using nanofiltration membranes and The transformation of wide bandgap semiconductors for visible-light photocatalytic degradation of organic dyes; Nanocomposite materials as electrode materials in microbial fuel cells for the removal of water pollutants; Plasmonic smart nanosensors for the determination of environmental pollutants.