Abstract Magnetic ion‐imprinted microspheres (IIM) with core‐shell structure were successfully prepared by reverse emulsion polymerization and applied to adsorb heavy metal ions from sewage. The semi‐interpenetrating polymer network composed of cross‐linked polyacrylamide (PAM) and linear chitosan (CTS) was used as the microgel shell of microspheres, which can not only fully retain the active sites of CTS but also tightly encapsulate magnetic particle nuclei. In addition, ion imprinting technology was used to further improve the adsorption capacity. In this study, the effects of PAM to CTS ratio on the thermal stability, magnetic properties, and microstructure of microspheres were investigated. Adsorption studies showed that IIM exhibited excellent selective adsorption of Cu(II), and the effects of initial concentration of metal ions, adsorption time, adsorbent dosage, pH, ionic strength, and cycle times on adsorption of Cu(II) by IIM‐2 were also studied. In addition, it was revealed that pseudo‐second‐order kinetic model and Langmuir isotherm model could better simulate the adsorption kinetic and isotherm of IIM‐2 for Cu(II), respectively. At 30°C and pH 5.0, the theoretical maximum adsorption capacities for Cu(II) by IIM‐2 were 151.13 mg/g. X‐ray photoelectron spectroscopy and Zeta potential study showed that the adsorption mechanism of IIM‐2 was a combination of electrostatic interaction and ion exchange.
Abstract Polyethersulfone (PES) membranes have a high tendency to scale due to their inherent hydrophobicity, which limits their application and increases water treatment costs. To regulate the size of the pores of PES and prevent clogging, different qualities of poly(ethylene glycol) 38 ‐block‐poly(propylene glycol) 8 (PEG‐PPG) were introduced and screened for the best ratios. Further introduced synthesized nitrogen‐doped titanium dioxide (N‐TiO 2 ), anti‐fouling and photocatalytic PES ultrafiltration membranes (N‐TiO 2 @M) were prepared. N‐TiO 2 @M3 exhibited bovine serum albumin rejection rate of 93.8% and achieved a methylene blue photocatalytic efficiency of 95.3% after 120 min of operation. Furthermore, N‐TiO 2 @M4 showcased a water contact angle of 41.0°. Notably, the pure water flux of N‐TiO 2 @M4 surged by 499.3% compared to that of PES membrane. The fouling resistance ratio for membrane flux witnessed an increase from 70.0% to 82.7%, demonstrating the enhanced durability of N‐TiO 2 @M4. Moreover, the comprehensive analysis for N‐TiO 2 @M4 revealed a total contamination rate of 40.2%. The irreversible contamination rate of N‐TiO 2 @M4 after 1 h of ultraviolet light (UV) cleaning was 5.7%, and the irreversible contamination rate after 1 h of visible light irradiation was 6.7%. The method for mixing N‐TiO 2 and PEG‐PPG is straightforward and convenient, offering potential for the development of N‐TiO 2 @M with resistance to pollution and degradation in visible/UV light.
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