Recent Advances in Adsorptive Removal of Dyes from Wastewater: Mechanisms and Performance of Advanced Adsorbents

The increasing discharge of dye-containing wastewater from textile and related industries has become a major environmental concern because of the toxicity, persistence, and poor biodegradability of many synthetic dyes. This review presents an overview of dye classification, chemistry, environmental impacts, and wastewater treatment technologies, with particular emphasis on adsorption as an effective dye removal method. The fundamental adsorption mechanisms, including electrostatic attraction, π–π interactions, hydrogen bonding, pore filling, and surface complexation, are discussed. Furthermore, the adsorption performances of metal–organic frameworks (MOFs), activated carbon, bioadsorbents, polymeric adsorbents, and carbon nanotubes (CNTs) are comparatively evaluated based on adsorption capacity, kinetics, isotherm models, and thermodynamic behavior. Among the reported systems, MOFs and CNT-based materials exhibit exceptionally high adsorption capacities, whereas activated carbon and bioadsorbents offer cost-effective and sustainable alternatives. Overall, this review highlights recent advances in adsorbent materials and provides insights into the development of efficient and environmentally friendly technologies for dye-contaminated wastewater treatment.