V/Ce共掺杂TiO2光催化降解甲醛的实验研究

采用溶胶凝胶法制备了不掺杂、V 掺杂、Ce掺杂、V/Ce共掺杂纳米TiO₂光催化剂,并将其分别负载于瓷砖上,利用X射线衍射分析（XRD）和扫描电镜分析（SEM）技术对薄膜样品的结构和形貌进行了表征。通过对甲醛的降解实验评价光催化剂的光催化活性。实验结果表明,光催化剂的负载量、共掺杂离子的掺杂量、掺杂配比、煅烧温度影响纳米TiO₂的光催化活性。V/Ce共掺杂TiO₂光催化剂产生了协同效应,其光催化活性优于纯TiO₂和单掺杂TiO₂样品。     

Enhanced arsenate removal from aqueous solution by Mn-doped MgAl-layered double hydroxides

Environmental Science and Pollution Research - In this study, Mn-doped MgAl-layered double hydroxides (LDHs) were successfully synthesized for efficient removal arsenate from aqueous solution. The...     

Producing biodiesel from waste animal oil by modified ZnO

Biodiesel produced by transesterification of waste animal oil is a promising green fuel in the future. ZnO-Al₂O₃ and ZnO/Zn₂Al composition oxides were prepared by co-precipitation method and impregnation method, respectively. The above catalysts were characterized by X-ray diffraction (XRD), Brunauer--Emmett--Teller (BET) and CO₂ adsorption and temperature-programmed desorption (CO₂-TPD) and show that the high activity for the catalyst is attributed to its high alkalinity. The reaction parameters were optimized and the results show that the transesterification ratio of waste animal oil can reach 98.7% with 10% ZnO/Zn₂Al catalyst after 2 h. Moreover, 10%ZnO/Zn₂Al compound oxides can be active for the successive cycles. The glycerol as a predominant by-product after transesterification is of high purity with high use value.     

Geochemical processes of mercury in Wujiangdu and Dongfeng reservoirs, Guizhou, China

The geochemical processes of mercury in Dongfeng (DF) and Wujiangdu (WJD) reservoirs, which were constructed in 1992 and 1979, respectively in Wujiang River, which is the upper branch of Yangtze River were investigated. One sampling site was chosen upriver of 1 km from the dam for each reservoir. Three sampling campaigns were conducted at these sampling sites in December 2003, April 2004 and July 2004, respectively. The distributions of different mercury species in the water column, sediment, and sediment pore water were studied. We found that the sediment is the net source of both inorganic and MeHg to the water column for both reservoirs. The MeHg diffusion fluxes in WJD reservoir at all sampling campaigns were significantly higher than those in DF reservoir. Our study demonstrated that the high primary productivity in the reservoir produced elevated organic matter content that would favor the methylmercury production in sediment.     

Pollution characterization and diurnal variation of PBDEs in the atmosphere of an E-waste dismantling region

Diurnal air samples were collected from the E-waste dismantling region Guiyu and the underwear industry region Chendian. This was the first report to present the diurnal variation of PBDEs in the atmosphere. The average concentrations of 11 PBDE congeners were 11,742 pg m⁻³ in the daytime, and 4830 pg m⁻³ at night in Guiyu, while the concentrations were lower in Chendian with 376 pg m⁻³ in the daytime, and 237 pg m⁻³ at night. BDE-209 accounted for 22% and 31.3% of the total PBDEs in Guiyu and Chendian, respectively. The diurnal variation trends of BDE-47, -99, -153, -183, and -209 were also analyzed in detail in the two regions.     

重金属吸附剂壳聚糖的改性研究进展

综述了重金属吸附剂壳聚糖改性研究的新进展,介绍了交联与接枝等改性方式对壳聚糖稳定性的影响及改性后的壳聚糖对水体中重金属离子吸附性能的改善.针对壳聚糖改性中仍然存在的一些问题,指出今后研究中值得关注的方向.     

计算毒理学在内分泌干扰物筛选上的应用和展望

内分泌干扰物通过干扰内分泌系统导致多种疾病,如生殖疾病、肥胖症甚至癌症。然而,面对环境中大量潜在的内分泌干扰物,传统的体外、体内评估方法由于成本高、耗时长等问题,难以实现内分泌干扰物的高通量筛查。计算毒理学逐渐发展成为被美国环保局(Environmental Protection Agency,EPA)、经济合作与发展组织(Organization for Economic Co-operation and Development,OECD)等机构所推荐的内分泌干扰物筛选与预测方法。本文综述了计算毒理学在内分泌干扰物筛选上的进展,主要包括分子对接和分子动力学模拟的应用,并对有害结局路径(adverse outcome pathway,AOP)的方法进行介绍和展望。     

菲和镉单一及复合污染条件下在毛蚶体内的富集动力学研究

采用室内半静态双箱动力学模型实验,研究了菲和镉单一及复合污染条件下在毛蚶(Anadara subcrenata)体内的生物富集,通过对富集与释放过程中毛蚶体内菲和Cd的富集量进行非线性曲线拟合,获得了菲和Cd单一及复合污染条件下在毛蚶体内的吸收速率常数k1、释放速率常数k2、生物富集因子BCF、生物半衰期B1/2和平衡状态下最大富集量CA max等动力学参数。实验结果表明,菲和Cd在实验前期富集速率较高,8 d以后富集速率减缓,释放阶段与富集阶段相似。毛蚶对菲的BCF值为37.80,远大于Cd的BCF值13.12,且生物半衰期时间更长,菲更容易在生物体内富集。菲和Cd联合暴露条件下,在毛蚶体内的CA max和BCF值均大于单一作用,说明二者同时暴露时,毛蚶对菲和镉的吸收富集均有所增强。实验模型拟合度较好,输出值和实测值之间无显著性差异,拟合方程和拟合参数可信。     

Copper recovery from waste printed circuit boards concentrated metal scraps by electrolysis

Copper recovery is the core of waste printed circuit boards (WPCBs) treatment. In this study, we proposed a feasible and efficient way to recover copper from WPCBs concentrated metal scraps by direct electrolysis and factors that affect copper recovery rate and purity, mainly CuSO₄·5H₂O concentration, NaCl concentration, H₂SO₄ concentration and current density, were discussed in detail. The results indicated that copper recovery rate increased first with the increase of CuSO₄·5H₂O, NaCl, H₂SO₄ and current density and then decreased with further increasing these conditions. NaCl, H₂SO₄ and current density also showed a similar impact on copper purity, which also increased first and then decreased. Copper purity increased with the increase of CuSO₄·5H₂O. When the concentration of CuSO₄·5H₂O, NaCl and H₂SO₄ was respectively 90, 40 and 118 g/L and current density was 80 mA/cm², copper recovery rate and purity was up to 97.32% and 99.86%, respectively. Thus, electrolysis proposes a feasible and prospective approach for waste printed circuit boards recycle, even for e-waste, though more researches are needed for industrial application.

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Recovery of rare and precious metals from urban mines—A review

Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals (RPMs) from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional (pyrometallurgical, hydrometallurgical, and biometallurgical processing), and emerging (electrochemical, supercritical fluid, mechanochemical, and ionic liquids processing) technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used for RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies—electrochemical, supercritical fluid, ionic liquid, and mechanochemical—have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.

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