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Zhao J.H.,Tianjin Institute of Urban Construction | Zhao J.H.,Tianjin Key Laboratory of water Quality Science and Technology | Lai Y.P.,Tianjin Institute of Urban Construction
Materials Science Forum | Year: 2011

High purity nanometer magnesium hydroxide is produced by impinging stream reaction crystallization method using bischofite as feedstock. Effects of operation conditions on the impinging stream of Mg (OH)2 are reported and the control factors of purity are confirmed. The morphology of the powder was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Result shows that purity of Mg (OH)2 can reach 99% and the mean size of crystal is 13.5nm. Surface modification of nano-sized magnesium hydroxide using four surface modifiers such as sodium steatite, sodium laurylsulfonate, sodium oleate and sodium silicate were investigated in this paper. The modified magnesium hydroxide has smaller particle size, larger powder contact angle, slower sedimentation velocity, the less in-oil capacity than unmodified sample © (2011) Trans Tech Publications. Source

Xiong Z.-H.,Tianjin Institute of Urban Construction | Xiong Z.-H.,Tianjin Key Laboratory of water Quality Science and Technology | Yu W.-L.,Tianjin Institute of Urban Construction | Hu P.,Tianjin Institute of Urban Construction
Huanjing Kexue/Environmental Science | Year: 2010

Under the sunlight irradiation, the four common trace pollutants such as metronidazole, diclofenac, sulfamethoxazole and ibuprofen were degradated and mineralized by the hydroxyl radical(·OH) generated from decomposition of H 2O 2 catalyzed by ferrioxalate(FeOx), and the toxicity of the water solution containing degradated products and intermediates were evaluated. The factors affecting the removal of the TOC, such as the initial concentration of H 2O 2, FeOx, and the pH, were investigated through an indicator of total organic carbon. The disappearing rate of pollutants in aqueous solution was explained according to the chemical structure of the pharmaceuticals; the biotoxicity of the pharmaceuticals and the intermediates were evaluated by EC 50 value of pharmaceutical solution to the Chlorella. The appropriate operating conditions were achieved at pH 3 with initial concentrations of 300 mg · L -1 H 2O 2 and 75 mg · L -1 FeOx at the conditions such as the initial concentration of four drugs were 20 mg · L -1, respectively. The order of the degradation rate for the pharmaceuticals is metronidazole > ibuprofen > sulfamethoxazole > diclofenac. During the reaction, the biological toxicity increases with time and then decreases rapidly, along with appearance and disappearance of intermediates. Finally, a model on reaction mechanism was proposed, where Solar/FeOx/H 2O 2 system was used for the degradation of the pharmaceuticals with low concentration in aqueous solution. Source

Liu H.,University of Shanghai for Science and Technology | Zhu M.,University of Shanghai for Science and Technology | Gao S.,University of Shanghai for Science and Technology | Xia S.,Tongji University | Sun L.,Tianjin Key Laboratory of water Quality Science and Technology
Chemical Engineering Journal | Year: 2014

Role of configurations on enriching denitrifying phosphorus removing bacteria (DPB) by biological nutrient removal processes was discussed. Effects of configurations on enhancement of denitrifying phosphorus removal in a novel nutrient removal process, the STB (six-tank-bioreactor) process were investigated. Profiles of model intracellular compounds i.e. glycogen and PHA (poly-hydroxyalknoates) under different configurations were characterized in order to reveal the biochemical pathway that DPBs might follow in the STB process. Mass flow characteristics of main pollutants under different configurations were also illustrated. Results showed that a higher anoxic to total volume ratio and the multi-barrier bioreactor strategy were crucial factors to enhance denitrifying phosphorus removal in the STB process. Both of the configurations performed well with average removal efficiencies of 74%, 98%, 51% and 85% under configuration I, and 74%, 99%, 72% and 70% under configuration II for COD, NH3-N, TN and TP respectively. A higher denitrifying phosphorus removal efficiency was achieved under configuration II than configuration I due to a bigger anoxic to total volume ratio. © 2013 Elsevier B.V. Source

Dai Y.-Y.,Tianjin Institute of Urban Construction | Dai Y.-Y.,Tianjin Key Laboratory of water Quality Science and Technology | Yuan J.,Tianjin Institute of Urban Construction | Yuan J.,Tianjin Key Laboratory of water Quality Science and Technology | And 2 more authors.
Key Engineering Materials | Year: 2012

As filter media sand, ceramic has the certain removal effect in treating turbidity, organic matter from water. but the removal rate is limited. Modied filter could change filter surface characteristics. in this article, modied ceramic with aluminum hydroxide. the experimental resulta showe that the trentment effect of ceramics filter coated aluminum is higher than ordinary ceramic in turbidity, COD Mn, UV 254 in the water, the removal efficacy is 96.64%,38.14%,47.77%respectively, aftercoated aluminum ceramic getting through the filter candle, the Zeta potential of filter water is more close to zeto point and helpful for adhering to particles and intercepted. © (2012) Trans Tech Publications. Source

Xiong Z.,Tianjin Key Laboratory of water Quality Science and Technology | Xiong Z.,Tianjin Institute of Urban Construction | Zhu L.,Tianjin Key Laboratory of water Quality Science and Technology | Zhu L.,Tianjin Institute of Urban Construction
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2013

A novel molecularly imprinted polymer nanocomposite material named as MWCNTs@BPA-MIPs was prepared on Multiwalled Carbon Nanotubes (MWCNTs) surface by introducing an unsaturated side chain, -CHCH2, on the MWCNTs surface via carboxylation, acylation and amidation and then using bisphenol A (BPA) as template molecules, 4-vinyl pyridine (4-VP) as the functional monomer, and ethylene glycoldimethacrylate (EGDMA) as the cross-linker. The structure and morphology of the obtained MWCNTs@BPA-MIPs were characterized by scanning electron micrograph (SEM), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetry analysis and a stable imprinted layer was found to be grafted on the surface of MWCNTs. The adsorption properties of MWCNTs@BPA-MIPs to BPA were demonstrated by equilibrium rebinding experiments and Scatchard analysis. The results revealed that the adsorption capacity of BPA onto the MWCNTs@BPA-MIPs is up to 123.8 mg·g-1. The nanocomposite material prepared in our work possessed better selectivity, higher capacity and faster kinetics for template molecules of BPA than those for the analogues of BPA molecules, such as bisphenol C (BPC) and o-nitrophenol (o-NP). Source

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