Immobilization Strategies of Cyclodextrins on Ferrimagnetic Nanoparticles for Dye Water Remediation: A Review

ABSTRACT: This paper provides a comprehensive review of the synthesis, use, and advantages of cyclodextrin-derivatized ferrimagnetic nanoparticles for the removal of textile dyes from natural waters. Dyes make their way into natural water systems and affect ecosystems and human health. Water soluble natural cyclodextrins (CD) are able to include dyes into their hydrophobic cavities. To extract the pollutant from water, the host molecules need to be tethered to insoluble supports, such as magnetic nanoparticles, making possible the extraction of the pollutant from the water using a simple magnet. Thus, after washing treatment, the pollutant is extracted, and the support is regenerated for a new remediation cycle. We report herein the synthetic strategies to immobilize β-cyclodextrin onto magnetic nanoparticles MNP@CD using weak to strong bindings, and the analytical methods used to characterize and monitor their effectiveness. Hydroxyl groups present on the CD scaffold can chelate iron cores by coprecipitation, solvothermal reaction, polymerization, carboxylic acid coordination, and silica bonding. An assessment of various dye adsorption capacities of MNP@CD is reported, spanning a range of 3 orders of magnitude, from 2.38 to 2780 mg of dye/g. The recyclability of the magnetic nanoparticles, with excellent removal rates of 90% after a few cycles, is also discussed.