Selective identification and separation of ReO4- by biomimetic flexible temperature-sensitive imprinted composite membranes.

A new type of temperature-sensitive imprinted composite membranes(ICMs) was developed. Poly N,N-diethylacrylamide (DEA) blocks, as temperature-sensitive polymer, were grafted onto the substrate of the imprinted polymer separation layer to endow membranes with better adsorption effect. The comprehensive properties of the imprinted composite membranes were adequately tested and evaluated in detail. Results showed that ReO4- -ICMs (Re-ICMs) with temperature-sensitive recognition sites could adjust the structure of the imprinted holes at different temperatures, which presented excellent performance in the selective separation and purification of ReO4-. The prepared Re-ICMs exhibit the maximum adsorption capacity of 0.1639 mmol/g at 35 °C with the equilibrium adsorption time of 2 h. After ten adsorption/desorption cycles, Re-ICMs could still maintain 73.5% of the original adsorption capacity, the separation degree of ReO4-/MnO4- was only reduced from the initial 24.5 to 15.9, and the desorption ratio dropped from 80.4% to 68.4%, indicating that Re-ICMs have excellent adsorption and separation performance and reusability.

Smart ion imprinted polymer for selective adsorption of Ru(â ¢) and simultaneously waste sample being transformed as a catalyst.

In this work, a temperature-sensitive block polymer PDEA-b-P(DEA-co-AM) was synthesized and then introduced into the preparation of a smart Ru(Ⅲ) imprinted polymer (Ru-IIP) to selectively adsorption Ru(Ⅲ) first. Then the waste Ru-IIP was converted into a catalyst in-situ for recycle. The structure and morphology of the prepared polymer were characterized by Fourier transform infrared spectrometer, Scanning electron microscope, BET surface area and Thermogravimetric analysis. The adsorption properties of the synthesized smart material were investigated in terms of adsorption pH, adsorption kinetics and adsorption isotherm. Results documented that the optimal adsorption temperature and pH were 35 °C and 1.5 respectively, the maximum adsorption capacity was 0.153 mmol/g, and the adsorption processes of Ru-IIP were more suitable to be expressed by pseudo-first-order kinetic and Langmuir model. The selectivity studied in different binary mixed solutions showed that Ru-IIP has good selectivity, and reusability results showed that Ru-IIP still maintains a good adsorption effect after 8 cycles. In addition, the waste Ru-IIP, a Ru(Ⅲ) remained waste sample was employed as the catalyst for the synthesis of imines, and result showed the mass of adsorbent would reduce after the completion of catalysis, which could not only catalyze the reaction but also reduce pollution.

Ambient air benzene at background sites in China's most developed coastal regions: exposure levels, source implications and health risks.

Benzene is a known human carcinogen causing leukemia, yet ambient air quality objectives for benzene are not available in China. The ambient benzene levels at four background sites in China's most developed coastal regions were measured from March 2012 to February 2013. The sites are: SYNECP, in the Northeast China Plain (NECP); YCNCP, in the North China Plain (NCP); THYRD, in the Yangtze River Delta (YRD) and DHPRD, in the Pearl River Delta (PRD). It was found that the mean annual benzene levels (578-1297 ppt) at the background sites were alarmingly higher, especially when compared to those of 60-480 pptv monitored in 28 cities in the United States. Wintertime benzene levels were significantly elevated at both sites (SYNECP and YCNCP) in northern China due to heating with coal/biofuels. Even at these background sites, the lifetime cancer risks of benzene (1.7-3.7E-05) all exceeded 1E-06 set by USEPA as acceptable for adults. At both sites in northern China, good correlations between benzene and CO or chloromethane, together with much lower toluene/benzene (T/B) ratios, suggested that benzene was largely related to coal combustion and biomass/biofuel burning. At the DHPRD site in the PRD, benzene revealed a highly significant correlation with methyl tert-butyl ether (MTBE), indicating that its source was predominantly from vehicle emissions. At the THYRD site in the YRD, higher T/B ratios and correlations between benzene and tetrachloroethylene, or MTBE, implied that benzene levels were probably affected by both traffic-related and industrial emissions.

Sources of C2-C4 alkenes, the most important ozone nonmethane hydrocarbon precursors in the Pearl River Delta region.

Surface ozone is becoming an increasing concern in China's megacities such as the urban centers located in the highly industrialized and densely populated Pearl River Delta (PRD) region, where previous studies suggested that ozone production is sensitive to VOC emissions with alkenes being important precursors. However, little was known about sources of alkenes. Here we present our monitoring of ambient volatile organic compounds at four representative urban, suburban and rural sites in the PRD region during November-December 2009, which experienced frequent ozone episodes. C2-C4 alkenes, whose total mixing ratios were 11-20% of non-methane hydrocarbons (NMHCs) quantified, accounted for 38-64% of ozone formation potentials (OFPs) and 30-50% of the total hydroxyl radical (OH) reactivity by NMHCs. Ethylene was the most abundant alkene, accounting for 8-15% in total mixing ratios of NMHCs and contributed 25-46% of OFPs. Correlations between C2-C4 alkenes and typical source tracers suggested that ethylene might be largely related to vehicle exhausts and industry activities, while propene and butenes were much more LPG-related. Positive Matrix Factorization (PMF) confirmed that vehicle exhaust and liquefied petroleum gas (LPG) were two major sources that altogether accounted for 52-62%, 58-77%, 73-83%, 68-79% and 73-84% for ethylene, propene, 1-butene, trans-2-butene and cis-2-butene, respectively. Vehicle exhausts alone contributed 32-49% ethylene and 35-41% propene. Industry activities contributed 13-23% ethylene and 7-20% propene. LPG instead contributed the most to butenes (38-65%) and substantially to propene (23-36%). Extensive tests confirmed high fractions of propene and butenes in LPG then used in Guangzhou and in LPG combustion plumes; therefore, limiting alkene contents in LPG would benefit regional ozone control.