Mingyang Sun,Jiaai Hou,Guanghuan Cheng,Shams Ali Baig,Lisha Tan,Xinhua Xu
Multipurpose utilization of flue gas desulfurization (FGD) gypsums releases mercury into environment and poses threats to public health. Determining Hg speciation is essential not only for predicting its toxicity and mobility but also for designing effective remediation strategies. Sequential chemical extraction (SCE) method was used to analyze Hg speciation in this study. The total Hg concentration in four samples ranged from 0.61 to 1.63 μg/g. XRD and EDX analysis revealed that the main chemical composition of FGD gypsum was calcium sulfate (CaSO 4 ). SCE result indicated that Hg was mainly distributed in the strong complex phase, ranging from 60% to 80%. Water soluble mercury in Sample SX accounted for 30% of the total extract, which might be attributed to the relatively high chlorine content in coal. Moreover, the mobility of Hg from FGD gypsum was also investigated in this study, which exhibited biphasic kinetics. The rapid release of Hg was related to the ratio of water soluble Hg at some extent ( R 2 = 0.818), which signified of more attentions for its stabilization. This study also suggested theoretical framework for the environmental risk associated with FGD gypsum during its usage and disposal.
Disinfecting pathogenic microorganisms in water streams efficiently and massively is still a big challenge in point-of-use situations. Nowadays, available technologies are still suffering from irreversible consumption of disinfectants, production of carcinogenic byproducts, and high filtration resistance. Herein, we designed a chlorine rechargeable fiber-supported biocidal porous organic polymer (i.e., FPOP) according to a surface-activated in situ condensation methodology on cotton fibers. The presence of secondary amines in the FPOP enables it to be chlorinated to form N-halamine structures after treating it with a diluted chlorine bleach solution, allowing the FPOP to perform a potentially rapid and robust biocidal activity. The chlorinated FPOP, which possessed the combination of interfiber macropores and intrinsic meso/micropores from the porous organic polymer, showed a high specific surface area, large and rechargeable active chlorine content (∼7000 ppm), long-term stability, efficient biocidal activity (>99.9999% bacteria reduction within 1 min of contact), and desirable filtration flux (>2000 L/m2 h). The successful fabrication of FPOP indicated the promise of applying it as a filtration material for point-of-use water disinfection with superior killing capacity, high filtration flux, and low cost.
Jun Li,Peng Huang,Xiaoqi Cheng,Rongmin Wang,Yufeng He,Pengfei Song
Bacterial contamination in water bodies is potentially transmissible to humans, making water bodies a major pathway of bacterial transmission. However, existing hydantoin copolymer nanoparticles did not achieve the regulation of nanoparticle dispersion and particle size by adjusting the ratio of hydrogen-donors and hydrogen-acceptors. To tackle this issue, amphiphilic hydantoin copolymer nanoparticles (P(VBDH-BA-NVP)NPs) were synthesized by modulating hydrogen-donors and hydrogen-acceptors using emulsion polymerization, and amphiphilic N-halamine copolymer nanoparticles (P(ClV-BA-NVP)NPs) were subsequently prepared via chlorination treatment. Impressively, nanoparticle dispersion and particle size were modulated by adjusting the ratio of hydrogen-donors and hydrogen-acceptors. With the increase of nanoparticle dispersion and the decrease of particle size, the active chlorine content was gradually enlarged, and the antibacterial performance was progressively enhanced against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). More importantly, amphiphilic N-halamine copolymer nanoparticles with two-dimensional dispersing (2DD-P(ClV-BA-NVP)NPs) exhibited excellent antibacterial properties, which benefited from the dual coordination of direct contact killing and indirect release killing in aqueous medium. Through designing P(VBDH-BA-NVP)NPs with hydrogen bond interactions, this approach aims to achieve the constitutive relationship between the effective exposure of active sites and the antibacterial effect.
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