Quaternary ammonium β-cyclodextrin-conjugated magnetic nanoparticles as nano-adsorbents for the treatment of dyeing wastewater: Synthesis and adsorption studies

The preparation of sorbents has been paid great attention on dye wastewater treatment. In this article, a novel multi-layer magnetic adsorbent (GEPCD-MNPs) was prepared by coating a multi-layer cationic polymer (GEPCD) onto magnetic nanoparticles (MNPs) via the formation of an ester bond. The physiochemical characteristics of the GEPCD-MNPs were characterized by FTIR, X-ray diffraction, contact angle, SEM, BET, VSM and zeta potential analysis. GEPCD-MNPs were used to treat Congo red (CR) and hexavalent chromium (Cr (VI)) ions in simulated dye wastewater. The adsorption capacities of the GEPCD-MNPs for CR and Cr(VI) reached 389.1 mg/g and 118 mg/g, respectively, which was due to the multi-cavity structure and active functional groups (-COOH and -OH) contained in the GEPCD-MNPs. According to the adsorption data, the dynamic and isothermal adsorption mode were studied, which revealed that the adsorption process was consistent with the pseudo-second-order model and Freundlich model. Meanwhile, the isothermal data for CR and Cr (VI) were analysed thermodynamically, which showed that the adsorption processes were spontaneous and that the adsorption of CR and Cr (VI) were endothermic. Moreover, the as-prepared adsorbent is economic viable and easily controllable for pollutants adsorption in industrial application.