A novel magnetic anion exchange resin NDM-1 was prepared through suspension polymerization and then functionalized with ammonolysis and alkylating agents.Its application for selective removal of nitrate was performed in comparison with MIEX.The results demonstrated that NDM-1 achieved higher efficiency in nitrate removal than MIEX did,with or without the existence of competing anion SO_4^2- ascribed to its longer alkyl chains on exchange sites.Combined with the advantage of easy separation due toγ-Fe_2O_3 implanted,the magnetic anion exchange resin NDM-1 was considered to be superior to MIEX for nitrate removal in practical application.
Yang ZhouChen Dong ShuangQing ZhouMan Cheng ZhangPeng Hui LiAi Min Li
An anion exchange resin NDP-5 has been prepared successfully and applied on the selective removal of nitrate from SO_4^（2-）/ NO_3^- binary co-existence system.The composition and morphology of NDP-5 were confirmed by FT-IR and SEM.The NDP-5 resin exhibits the completely different behavior on the adsorption capacity,adsorption kinetic and the effect of the completing anion in the absence or presence of sulfate,compared to D213.And,the resultants of kinetic are well fitted by the pseudo-first-order and pseudo-second-order models.These results are very important to develop novel resins with great features.
Magnetic powder resin Q150 with high specific surface area of 1074 m2/g was prepared by the membrane emulsificationsuspension polymerization technique. Adsoption of tetracycline on the obtained sorbent Q150 was evaluted by using the granule resin （GR） XAD-4, the powder activated carbon （PAC） 1240AC and the granule activated carbon （GAC） HD4000 for comparison. It was found that Q150 had a larger adsorption capacity, faster kinetic and easier regeneration under alkaline condition. The results suggested that the powder resin （PR） Q150 would be a promising sorbent for removing antibiotics and even other organic micropollutants from the aquatic environment.
Qing ZhouI Man Cheng Zhang Chen Dong Shuang Zhe Qin Li Ai Min Li
The disposal of waste brines has become a major challenge that hinders the wide application of ion- exchange resins in the water industry in recent decades. In this study, high sulfate removal efficiency （80%-90%） was achieved at the influent sulfate concentration of 3600 mg/L and 3% NaC1 after 145 days in an expanded granular sludge bed （EGSB） reactor. Furthermore, the feasibility of treating synthetic waste brine containing high levels of sulfate and nitrate was investigated in a single EGSB reactor during an operation period of 261 days. The highest nitrate and sulfate loading rate reached 6.38 and 5.78 kg/（m3-day） at SO42--S/NO3-N mass ratio of 4/3, and the corresponding removal efficiency was 99.97% and 82.26% at 3% NaC1, respectively. Meanwhile, 454-pyrosequencing technology was used to analyze the bacterial diversity of the sludge on the 240th day for stable operation of phase X. Results showed that a total of 9194 sequences were obtained, which could be affiliated to 14 phyla, including Proteobacteria, Firmicutes, Chlorobi, Bacteroidetes, Synergistetes and so on. Proteobacteria （77.66%） was the dominant microbial population, followed by Firmicutes （12.23%） and Chlorobi （2.71%）.
Bilayer-silane-coated Fe304 nanoparticles with inner layer of tetraethoxy silane （TEOS） and outer layer of vinyltriethoxysilane （VTEO） were generated to enhance their acid resistance. These nanoparticles were copolymerized with vinylbenzyl chloride （VBC） using suspension polymerization, and then post-crosslinked. The resulting hypercrosslinked magnetic resin M150 presented specific bimodal property with large specific surface area of 1109 m2/g. It exhibited more excellent adsorption capacity of p- nitrophenol compared to another two magnetic adsorbents Q150 and MIEX~. Moreover, the acid stable property of the magnetite in MI50 extended its application at low pH value.
A high-surface-area carbon （KC-1） was prepared from waste polystyrene-based ion exchange resin by KOH activation and used for naphthalene adsorption. The carbon exhibited a good hydrophobic nature with developed porous structure, favoring the adsorption of organic compounds. The Brunauer-Emmett-Teller surface area and total pore volume of KC- 1 were 3442.2 and 1.68 cm3/g, respectively, which can be compared with those of KOH-activated carbons prepared from other precursors. Batch experiments were carded out to investigate the adsorption of naphthalene onto KC-1. The equilibrium data were analyzed by the Langmuir, Freundlich, and Polanyi- Manes isotherms and agreed with the Polanyi-Manes Model. The adsorption of naphthalene depended greatly on the porosity of the carbon, and the dispersive interactions between naphthalene and carbon could be relatively weak. The pH variation in aqueous solution had little effect on the adsorption process. The equilibrium time for 0.04 g/L of carbon dose was around 5 hr. Different models were used to evaluate the kinetic data and the pseudo second-order model was suitable to describe the kinetic process of naphthalene adsorption onto KC-1. Regeneration of spent carbon could be carded out effectively by alcohol treatment. The results indicated that KC-1 was a promising adsorbent for the removal of polycyclic aromatic hydrocarbons from aqueous solutions.
