Water pollution from industrial effluents, agricultural runoff, pharmaceutical residues, heavy metals, and synthetic dyes has emerged as one of the most pressing environmental challenges of the twenty-first century. Conventional treatment technologies often fail to achieve satisfactory removal of emerging and persistent contaminants at trace concentrations. Cyclodextrins (CDs) — cyclic oligosaccharides derived from the enzymatic conversion of starch — have attracted considerable scientific interest as versatile functional materials for water treatment owing to their distinctive truncated-cone architecture, which presents a hydrophilic exterior and a hydrophobic interior cavity capable of encapsulating a broad spectrum of organic and inorganic guest molecules through host–guest inclusion complexation. This narrative review provides a comprehensive and critical synthesis of the recent advances in CD-based materials for water and wastewater treatment, encompassing their structural and physicochemical foundations, cross-linked polymer systems, hybrid nanocomposites incorporating graphene oxide and magnetic nanoparticles, membrane technologies, and catalytic applications. A narrative approach was deliberately adopted because the breadth of the topic — spanning synthetic chemistry, environmental engineering, ecotoxicology, and process scale-up — does not lend itself to the homogeneous study populations, standardised outcome measures, and meta-analytic synthesis that characterise systematic reviews. Specific attention is devoted to the removal of heavy metals, organic micropollutants, pharmaceutical and personal care products, textile dyes, and persistent organic pollutants. Pilot-scale demonstrations, regeneration behaviour, economic considerations, environmental fate, and ecotoxicological implications of CD-based adsorbents are critically examined. Future research directions, including the integration of artificial intelligence for process optimisation, the development of bio-inspired and green-synthesised CD materials, and the scale-up challenges for full-scale implementation, are discussed. The review demonstrates that CD-based materials represent a highly promising platform for next-generation water remediation strategies, whilst also identifying key knowledge gaps that must be addressed to realise their full potential.
Geeta Verma (Wed,) studied this question.