Unlocking environmental solutions: a review of cyclodextrins in pollutant removal

Abstract

AbstractCyclodextrins are cyclic oligosaccharides characterized by a hydrophobic interior and a hydrophilic outside linked by α-1,4 glycosidic bonds. Cyclodextrins are biodegradable and generally considered environmentally friendly. These are utilized in diverse applications, encompassing environmental cleanup which is enhanced through the processes of cross-linking or surface modification. These molecules have a unique structure that enables them to form inclusion complexes with various guest molecules, including organic pollutants, pesticides, dyes, pharmaceuticals, and hydrocarbons. When used in water treatment, cyclodextrins can act as molecular sponges, trapping pollutants within their cavities through non-covalent interactions such as hydrogen bonding, van der Waals forces, and hydrophobic interactions. When cyclodextrins are introduced into water containing pollutants, the pollutants can enter the cavities of cyclodextrin molecules, forming inclusion complexes. This process effectively sequesters the pollutants from the surrounding water, reducing their concentration. It can often be regenerated and reused multiple times, making them cost-effective for water treatment applications. This review presents the primary applications of cyclodextrins for the adsorption of contaminants from various pollutants from diverse sources, based on recent publications.