Purification of high–toxicity beryllium–containing water resources using carbon dot–enhanced phosphoric acid/chitosan composite gels
Xu Zhao, Zhiwu Lei, Hongshuai Hou, Guanqing Lin, Yige Sun, Haoshuai Li, Xipeng Yang, Yucheng Su, Khan Muhammad Yaruq Ali, Eming Hu, Hongqiang Wang, Qingliang Wang, Fang Hu
Abstract
With the sensitization of carbon neutrality, the efficient removal of beryllium from beryllium-containing wastewater has gained increasing research interest in the environmental field. In this study, carbon dots (CDs)/phosphonated chitosan hydrogel (PCH@CDs) are prepared by cross-linking nanometer CDs with phosphoric acid, calcium hydroxide, and chitosan. The doping with CDs increases the number of adsorption active sites (AAS) on PCH@CDs, thereby improving the removal rates of small molecular pollutants. The adsorption isotherm results show that the maximum amount of Be(II) adsorbed by PCH@CDs in neutral water is approximately 59.84 mg/g. The excellent adsorption of Be(II) by PCH@CDs can be attributed to the homogeneous dispersion of CDs in PCH@CDs, which results in significant exposure of CDs binding sites to Be(II). In addition, the surface of PCH@CDs contains many phosphate groups, including N–H and O–H, which have strong synergistic adsorption capacity for Be(II). In simulated wastewater, the Be(II) distribution coefficient of PCH@CDs is 6.56 × 10 5 mL/g, which is significantly higher than that of other coexisting ions. Furthermore, PCH@CDs can reduce the Be(II) concentration to less than 5 µg/L when treating Be(II)-containing solutions with an initial Be(II) concentration of less than 5 mg/L.