Carbon-based nanomaterials for water treatment: A review of adsorption and catalytic mechanisms

Carbon-based nanomaterials (CBNs) have emerged as powerful tools for advanced water treatment, offering remarkable surface area, rich functional chemistry, and high adsorption and catalytic efficiencies. This review comprehensively examines the synthesis, properties, and pollutant removal mechanisms of key CBNs—including graphene oxide (GO), carbon nanotubes (CNTs), activated carbon nanoparticles, and biochar-derived nanomaterials—with a particular focus on the removal of priority pollutants such as heavy metals (Pb²⁺, Cr(VI)), pharmaceuticals (ciprofloxacin, tetracycline), pesticides (atrazine), and synthetic dyes (methylene blue).
The article delineates the fundamental removal mechanisms underpinning pollutant elimination by CBNs: adsorption driven by π–π interactions, hydrogen bonding, and electrostatic forces; redox-based transformations for heavy metal detoxification; and photocatalytic degradation in hybrid systems incorporating metal oxides. Performance metrics across different pollutant classes are critically compared, highlighting the superior adsorption capacities and kinetic advantages of functionalized and composite CBNs.
Key operational and environmental factors—such as pH, surface modification, ionic strength, and nanomaterial aggregation—are explored in relation to removal efficiency and recyclability. While laboratory results demonstrate impressive potential, real-world deployment remains limited by challenges including material recovery, aging, ecotoxicity, and the absence of regulatory frameworks governing environmental nanomaterials.
Future perspectives emphasize the need for green synthesis approaches, smart functionalization, material integration into hybrid systems, and life-cycle risk assessment to ensure safe and scalable implementation. By addressing current knowledge gaps and technical barriers, this review contributes a strategic roadmap toward realizing the promise of CBNs in achieving sustainable and high-performance water purification systems.