Iodinated X-ray contrast media (ICM) was frequently detected in the aqueous environment. In this work, the applicability of three graphene-based nanomaterials (graphene nanosheets (GNS), graphene oxide (GO), and reduced graphene oxide (rGO)) for the adsorptive removal of the six ICMs including iohexol , iopamidol , iomeprol , iopromide , iodixanol and ioversol from aqueous solution was firstly evaluated by batch adsorption method. Among the three graphene-based nanomaterials , the GNS displayed the best adsorption performances for the adsorption of the six ICMs. The maximum uptakes of the six ICMs by the GNS (161.5 mg g −1 for iohexol, 267.2 mg g −1 for iodixanol, 197.7 mg g −1 for iopromide, 197.0 mg g −1 for iopamidol, 109.6 mg g −1 for iomeprol, and 168.2 mg g −1 for ioversol) can rapidly achieved within 10 min and indicate no dependence on pH in the range of 4–9. The results obtained from the calculations of isotherms, kinetics and thermodynamic supported the occurrence of a chemisorption of the GNS for the six ICMs. The π-π interactions between benzene ring of the ICMs and the sp 2 -hybridized two-dimensional sheet of GNS were deemed the predominant adsorption mechanism.
Wen Xu,Shiwen Dong,Haijun Cheng,Stefanos Giannakis,Xiaohui Lu,Zhiqiao He,Da Wang,Shuang Song,Jun Ma
Mixed refractory organic wastewater containing both organic molecular and nanoparticle contrast agents poses a significant challenge for wastewater treatment. In this study, heterogeneous catalytic ozonation (HCO) technology was employed, creatively using the nanoparticle contrast agent Mn 3 O 4 /SiO 2 /C as a catalyst for the degradation of the organic molecular contrast agent iopamidol (IPM). This study aims to provide new insights and approaches to address the challenge of mixed contrast agent treatment in medical wastewater through a “treat-waste-with-waste” strategy. Mn 3 O 4 /SiO 2 /C exhibited an excellent IPM degradation efficiency, reaching 99.3 % within 30 min, compared with only 9.6 % IPM removal in the absence of catalyst ([cat] = 0.1 g L −1 , [IPM] 0 = 5 μM, [O 3 ] 0 = 3 mg L −1 , at pH 6.8 and 278 K). The Mn 3 O 4 , SiO 2 , and C in Mn 3 O 4 /SiO 2 /C were extensively integrated, and the proportion of Mn(II) in Mn 3 O 4 /SiO 2 /C was 39.9 %, as compared to 33.1 % in Mn 3 O 4 , which facilitated the generation of hydroxyl radicals. The siloxide and carbonaceous materials in Mn 3 O 4 /SiO 2 /C provided abundant sites for ozone adsorption and pollutant enrichment, promoting interfacial ozone contact with pollutants and subsequent catalytic reactions. The presence of structures such as Mn-O-Si and Mn-O-C in the material helps accelerate electron transfer, thus promoting electron capture and ozone decomposition. This strategy provides new insights for refractory pollutant elimination and serves as a guide for advancing green catalysis in water purification.
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