Selective oxidation of benzyl alcohols to benzoic acid catalyzed by eco-friendly cobalt thioporphyrazine catalyst supported on silica-coated magnetic nanospheres

A novel magnetically recoverable thioporphyrazine catalyst (CoPz(S-Bu)8/SiO2@Fe3O4) was prepared by immobilization of the cobalt octkis(butylthio) porphyrazine complex (CoPz(S-Bu)8) on silica-coated magnetic nanospheres (SiO2@Fe3O4). The composite CoPz(S-Bu)8/SiO2@Fe3O4 appeared to be an active catalyst in the oxidation of benzyl alcohol in aqueous solution using hydrogen peroxide (H2O2) as oxidant under Xe-lamp irradiation, with 36.4% conversion of benzyl alcohol, about 99% selectivity for benzoic acid and turnover number (TON) of 61.7 at ambient temperature. The biomimetic catalyst CoPz(S-Bu)8 was supported on the magnetic carrier SiO2@Fe3O4 so as to suspend it in aqueous solution to react with substrates, utilizing its lipophilicity. Meanwhile the CoPz(S-Bu)8 can use its unique advantages to control the selectivity of photocatalytic oxidation without the substrate being subjected to deep oxidation. The influence of various reaction parameters on the conversion rate of benzyl alcohol and selectivity of benzoic acid was investigated in detail. Moreover, photocatalytic oxidation of substituted benzyl alcohols was obtained with high conversion and excellent selectivity, specifically conversion close to 70%, selectivity close to 100% and TON of 113.6 for para-position electron-donating groups. The selectivity and eco-friendliness of the biomimetic photocatalyst give it great potential for practical applications.     

乙苯—苯乙烯装置道化学火灾爆炸危险指数评价

应用道化学公司"火灾、爆炸危险指数评价法(道七版)"计算乙苯—苯乙烯装置的火灾、爆炸危险指数,结果表明通过补偿火灾、爆炸危险指数,操作单元危险等级和危险程度可以接受。     

瓦斯发电站燃气内燃机烟气脱硝方案研究

自2011年国家将氮氧化物总量纳入总量控制指标范围以来,环保主管部门针对煤层气发电项目氮氧化物排放总量政策逐渐收紧,对迅速发展的瓦斯发电项目来说氮氧化物排放浓度和总量的控制得到越来越多的重视.结合近5年来山西省瓦斯发电站实际环评过程中遇到氮氧化物排放浓度控制的问题,针对燃气内燃机高温、低烟尘、低二氧化硫的烟气排放特点,选择四个脱硝工艺方案进行了探讨,对企业制定脱硝方案具有一定的参考价值.     

基于大数据分析的雾霾污染预测研究

对雾霾的监控预测已成为城市重点监测指标,传统雾霾监测方法使用的是高斯预测模型,在预测过程中会使用大量的参数以及逻辑关系,在大数据分析的趋势下已经不能承接海量相关大数据,针对上述问题,提出一种基于大数据分析的雾霾污染预测方法.建立数据K模型承接海量数据,对大数据特点趋势加以分析,使用组合算子对雾霾污染度预测,摒弃逻辑关系束缚以及大数据的驱使性,对特征数据进行类别掌控完成预测结果.通过对比实验的方式对提出的方法进行检验,实验结果表明:(1)基于大数据分析的雾霾污染预测方法能够在大数据环境下对雾霾污染度进行高精度预测;(2)与传统方法相比较能够承接大数据的变化;(3)摒弃逻辑关系的制约可以实现随时预测;(4)极大的缩减预测成本.     

新型消防员隔热防护服外层面料结构及加工

本文描述了一种新型消防员隔热防护服的外层面料。面料的结构由铝箔、聚酯膜和基布组成。通过对铝箔复合、涂胶等加工方法的摸索试验,试制了新型消防员隔热防护服的外层面料。     

镧、铈、钕对小鼠肝细胞核的氧化损伤作用

轻稀土元素进入生物体后主要累积于肝脏,进入肝细胞,分布于细胞核上.为探讨轻稀土元素对小鼠肝细胞核的氧化损伤作用,选用5周龄雄性封闭群(ICR)小鼠灌喂10、20和40 mg·kg-1的稀土元素镧(La)、铈(Ce)和钕(Nd),6周后测定小鼠肝细胞核中超氧化物岐化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(...     

Accumulation and remobilization of metals in superficial sediments in Tianjin, China

The concentrations of Cr, Ni, Cu, Zn, Cd, and Pb in superficial sediment samples collected from three representative sites (Yuqiao Reservoir, Haihe River, and Haihe River Estuary) in Tianjin, North China, were analyzed using various single extraction and sequential extraction procedures to determine their remobilization, extractability, and distribution patterns. Sediments from the Haihe River had higher metal concentrations and geo-accumulation indices, especially for Cd and Zn, than sediments from the other two sites, suggesting that the Haihe River has been heavily influenced by anthropogenic activities. In addition, over 31% and 28.2% of the total Cd in the Haihe River and the Yuqiao Reservoir, respectively, and 18.2% of the total Zn in the Haihe River were found to be associated with the exchangeable form, indicating the significant remobilization of Cd and Zn when compared with Cr and Ni. However, over 98% of the Ni and 78% of the Cr were most closely associated with the residue and oxidizable fractions, which resulted in their becoming environmentally immobile. Based on the Environmental Protection Agency method 3050B, Cd and Zn had the greatest extraction efficiency when a single extraction procedure using 0.5-mol L^???1 HCl, 0.43-mol L^???1 HAcO, and 0.05-mol L^???1 ethylene-diamine-tetra-acetic acid was conducted, with extraction yields of up to 72%, 68%, and 56% for Cd and 50%, 49%, and 29% for Zn, respectively, being obtained for the Haihe River sediments. This was followed by the yields of Cu and Pb and, finally, those of unpolluted metals such as Cr and Ni. HCl and acetic acid extraction provided equivalent information for predicting Cd and Zn mobility in the sediments studied and produced suitable results for quick screening.     

Distribution and ecotoxicological significance of trace element contamination in a ~150 yr record of sediments in Lake Chaohu, Eastern China

This paper presents the concentrations, vertical profiles and possible sources of selected major and trace elements in a sediment core covering ～150 years of sedimentation in Lake Chaohu, eastern China. Element concentrations were measured by portable X-ray Fluorescence Spectroscopy (XRF) and were used to evaluate possible environmental consequences of the recent industrialization in China. Statistical analyses identify four groups: (1) organic carbon (OC), total nitrogen (TN), Pb, Zn, and As associated with the use of chemical fertilizers and pesticides; (2) Mn, Cr, Ni and Cu from industrial and mining activities; (3) Fe, Rb, K, Co, Ti and Ca influenced by post-depositional processes and land exploitation; and (4) Zr and Sr from the soil. The vertical profiles of elements placed in the first two groups show distinct increases in concentrations above depths of 20 cm (~1978), coincident with the timing of industrialization in China, and the anthropogenic-derived fluxes are higher than the lithogenic-derived fluxes over the last three decades. With the exception of Zr and Sr, association of the measured metals with organic carbon and nitrogen suggests that organic matter may act as a carrier phase. The geoaccumulation index (I(geo)) reveals increased contamination from elements in the first two groups in recent years. Element concentrations, compared with the Effects Range-Low (ERL) and Effects Range-Median (ERM) levels set by NOAA, suggest that adverse biological effects from Ni contamination are very likely.     

Surfactant-assisted adsorption of uranyl ions in aqueous solution on TiO2/polythiophene nanocomposite

In this work, hexadecyltrimethylammonium-bromide (HTAB)-modified polythiophene (PTh)/TiO₂ nanocomposite (HTAB/PTh/TiO₂) was applied to remove uranyl ions (UO₂²⁺). FT-IR, XRD, ζ potential, TGA, SEM, and XPS were utilized to obtain the chemical and physical properties of HTAB/PTh/TiO₂. The effects of HTAB content, preparation temperature, and adsorption conditions on UO₂²⁺ removal were investigated comprehensively. And the UO₂²⁺ adsorption process on HTAB/PTh/TiO₂ was fitted to the Sips model with a saturated adsorption capacity of 234.74 mg/g, which was 6 times over TiO₂. The results suggested that the surfactant of HTAB can significantly improve the adsorption ability of TiO₂ for UO₂²⁺ ions. This work provides a strategy of surfactant modification for enhancing the separation and recovery ability of adsorbent toward UO₂²⁺ in the radioactive wastewater.