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Wang J.,Tsinghua University | Wang J.,Collaborative Innovation Center for Regional Environmental Quality | Yunus R.,Tsinghua University | Yunus R.,Xin Jiang Zhong Tai Chemical Co. | And 6 more authors.
Applied Surface Science | Year: 2015

Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnOx) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnOx/PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnOx layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO4 and then surface-deposition of MnOx particles from the bulk phase. The MnOx particles assembled with nanosheets were uniformly coated on the PET fibers. MnOx/PET showed good activity for HCHO decomposition at room temperature which followed the Mars-van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m3, space velocity ∼17,000 h-1 and relative humidity∼50%. This research provides a facile method to deposit active MnOx onto polymers with low air resistance, and composite MnOx/PET material is promising for indoor air purification. © 2015 Elsevier B.V. All rights reserved. Source

Sun J.,Xinjiang University | Zhou Q.-X.,Xinjiang University | Wang J.-D.,Xinjiang University | Gao G.,Xinjiang University | And 5 more authors.
Xiandai Huagong/Modern Chemical Industry | Year: 2014

ZSM-5-supported Bi-Cu catalyst is studied in detail for the hydrochlorination of acetylene. Appropriate amount of phosphoric acid is added into the impregnating solution before incipient impregnation. Then, a non-mercury novel catalyst (Bi+Cu) /ZSM-5 is prepared after calcinations. Using this catalyst, the initial catalytic activity and selectivity to vinyl chloride are as good as that using the industrial catalyst (HgCl2/AC). Moreover, the deactivated catalyst obtained can be regenerated by calcination. Using BET, TEM, EDS and TG, (Bi+Cu)/ZSM-5 catalyst is found to be deactivated by following mechanisms: (i) deposition of carbonaceous material, which blocked the pores and covered the active sites; (ii) the loss of active components and the collapse of the catalyst's framework. Gaseous HCl absorbed on the active sites may also result in deactivation of catalyst. Source

Wang L.,Xinjiang University | Wang F.,Xinjiang University | Wang J.,Xinjiang University | Tang X.,Xin Jiang Zhong Tai Chemical Co. | And 4 more authors.
Reaction Kinetics, Mechanisms and Catalysis | Year: 2013

A palladium catalyst (0.5 wt% of Pd) supported Y zeolite (HY) (Pd/HY) was prepared by ultrasonic-assisted impregnation. The potential of the catalyst for acetylene hydrochlorination was explored in a fixed-bed reactor at 160 °C, V(HCl)/V(C2H2) = 1.25 and gas hourly space velocity of C2H2 = 110 h-1. The catalyst exhibited high catalytic properties of acetylene conversion >95 % and vinyl chloride selectivity >90 %. The fresh and used catalysts were characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), energy dispersive spectrometer (EDS), Brunauer-Emmett-Teller (BET) analyzer, NH3 temperature programmed desorption (NH3-TPD) and infrared spectroscopy (IR). Analysis results showed that the active component Pd is uniformly dispersed on the Y zeolite surface. The generation of polymers, carbon depositions, and the decrease of catalyst acidity might course the deactivation of the catalyst. © Akadémiai Kiadó, Budapest, Hungary 2013. Source

Xia Y.,Beijing University of Chemical Technology | Kou H.,Beijing University of Chemical Technology | Shi S.,Beijing University of Chemical Technology | Chen X.,Beijing University of Chemical Technology | And 4 more authors.
Beijing Huagong Daxue Xuebao (Ziran Kexueban)/Journal of Beijing University of Chemical Technology (Natural Science Edition) | Year: 2015

A series of waterborne polyurethanes (WPU) based on sulfonic acid polyester polyols, toluene diisocyanate (TDI) or 3-isocyanatomethyl-3, 5, 5-trimethylcyclohexyl isocyanate (IPDI), 1, 4-butanediol and dimethylolpropionic acid (DMPA) have been prepared. The influence of the diisocyanate precursor, residual NCO content, the initial value of R(n(-NCO)/n(-OH)), and DMPA content on the particle size of the waterborne polyurethanes are discussed in detail. The results indicate that the particle sizes of WPUs with the same R value are similar for TDI and IPDI. When the mass fraction of residual NCO was 1.40%-2.78%, the initial value of R was less than 6 and DMPA had a mass fraction of 2.00%, the resulting WPU had a small particle size (24.5-63.2 nm) and good stability. ©, 2015, Beijing University of Chemical Technology. All right reserved. Source

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