高锰酸盐复合剂强化饮用水除污染生产性研究

采用依时间序列进行对比的方法,考察了高锰酸盐复合剂(PPC)对饮用水源的强化除污染效能。生产性实验结果表明,PPC具有优良的强化混凝和强化过滤效能,能显著降低水厂沉后水和滤后水的浊度、COD_Mn、UV₂₅₄等水质指标。与未投加时相比较,水厂投加PPC后沉后水和滤后水浊度分别降低了25%和33.3%,沉后水和滤后水COD_Mn去除率分别提高了15.3%和11.5%,UV₂₅₄去除率分别提高了16.3%和9.5%。同时,GC/MS分析表明PPC能有效去除水源水中的多种微量有机污染物,显著提高饮用水的化学安全性。PPC通过高锰酸钾的氧化作用,水合二氧化锰的吸附作用,以及各组分间的协同强化作用,显著提高了对水中污染物质的去除效率。     

液晶显示器液晶处理与铟回收技术

在实验室条件下,对液晶显示器回收的各个重要环节作了初步的探索,提出了一整套回收工艺.其中包括利用丙酮常温浸取去除偏光片、分离玻璃基板、溶解液晶,还包括利用硫酸溶液和二氧化锰联合浸取玻璃基板,铟的浸取率达89%.得到的铟的酸液经过萃取、置换和电解,可以得到铟的产品,为液晶显示器的资源化和无害化提供实验数据和技术支持.     

Diurnal and spatial variations of soil NOx fluxes in the northern steppe of China

NO_x emissions from biogenic sources in soils play a significant role in the gaseous loss of soil nitrogen and consequent changes in tropospheric chemistry. In order to investigate the characteristics of NO_x fluxes and factors influencing these fluxes in degraded sandy grasslands in northern China, diurnal and spatial variations of NO_x fluxes were measured in situ. A dynamic flux chamber method was used at eight sites with various vegetation coverages and soil types in the northern steppe of China in the summer season of 2010. Fluxes of NO_x from soils with plant covers were generally higher than those in the corresponding bare vegetation-free soils, indicating that the canopy plays an important role in the exchange of NO_x between soil and air. The fluxes of NO_x increased in the daytime, and decreased during the nighttime, with peak emissions occurring between 12:00 and 14:00. The results of multiple linear regression analysis indicated that the diurnal variation of NO_x fluxes was positively correlated with soil temperature (P < 0.05) and negatively with soil moisture content (P < 0.05). Based on measurement over a season, the overall variation in NO_x flux was lower than that of soil nitrogen contents, suggesting that the gaseous loss of N fromthe grasslands of northern China was not a significant contributor to the high C/N in the northern steppe of China. The concentration of NO_x emitted from soils in the region did not exceed the 1-hr National Ambient Air Quality Standard (0.25 mg/m³).     

Visible-light-driven photocatalytic inactivation of bacteriophage f2 by Cu-TiO2 nanofibers in the presence of humic acid

Pathogenic viruses in drinking water are great threats to public health. Visible-light-driven photocatalysis is a promising technology for virus inactivation. However, the existing photocatalytic antiviral research studies have mostly been carried out in single-component systems, neglecting the effect of natural organic matter, which exists widely in actual water bodies. In this paper, electrospun Cu-TiO₂ nanofibers were prepared as photocatalysts, and their photocatalytic antiviral performance in the presence of humic acid (HA) was comprehensively studied for the first time. The properties of the reaction mixture were measured during the reaction. In addition, the safety, reliability and stability of photocatalytic disinfection in the mixed system were evaluated. The results showed that the virus removal efficiency decreased with the increase of the HA concentration. The type of reaction solution, such as PBS buffer solution or water, did not affect the removal efficiency noticeably. Under acidic conditions, the electrostatic forces between photocatalysts and viruses were strengthened, leading to higher virus removal efficiency. As the reaction time went on, the pH value in the solution increased first and then tended to be stable, the conductivity remained stable, and the dissolved oxygen increased first and then decreased. The safety test showed that the concentration of Cu ions released into the solution was lower than specified by the international standards. No photoreactivation was observed, and the addition of HA significantly reduced the reutilization efficiency of the photocatalysts.     

Microbial reduction of uranium (VI) by Bacillus sp. dwc-2: A macroscopic and spectroscopic study

The microbial reduction of U(VI) by Bacillus sp. dwc-2, isolated from soil in Southwest China, was explored using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge spectroscopy (XANES). Our studies indicated that approximately 16.0% of U(VI) at an initial concentration of 100 mg/L uranium nitrate could be reduced by Bacillus sp. dwc-2 at pH 8.2 under anaerobic conditions at room temperature. Additionally, natural organic matter (NOM) played an important role in enhancing the bioreduction of U(VI) by Bacillus sp. dwc-2. XPS results demonstrated that the uranium presented mixed valence states (U(VI) and U(IV)) after bioreduction, which was subsequently confirmed by XANES. Furthermore, the TEM and high resolution transmission electron microscopy (HRTEM) analysis suggested that the reduced uranium was bioaccumulated mainly within the cell and as a crystalline structure on the cell wall. These observations implied that the reduction of uranium may have a significant effect on its fate in the soil environment in which these bacterial strains occur.     

“后小康”时期我国排污许可制改革实施路线图研究

排污许可制度是发达国家普遍实行并证明行之有效的点源管理制度。"十三五"以来,我国以排污许可制度为核心的固定污染源管理体系进入快速高效构建期。2020年后,我国将进入"后小康社会"时期,排污许可制度改革与实施也将进入一个新时期。本文在充分研究目前排污许可制度改革面临问题的基础上,参考国际经验,提出"后小康"时期排污许可制改革的路线图。围绕环境质量改善,通过"后小康"时期排污许可制度的进一步改革与创新,使得中国排污许可制度更加完善、内容规范细致,让排污许可制真正成为固定污染源环境管理的核心制度,为确保"十九大"提出的"环境质量根本好转"的目标打下坚实基础。     

The role of doped-Mn on enhancing arsenic removal by MgAl-LDHs

To meet the challenges posed by global arsenic water contamination, the MgAlMn-LDHs with extraordinary efficiency of arsenate removal was developed. In order to clarify the enhancement effect of the doped-Mn on the arsenate removal performance of the LDHs, the cluster models of the MgAlMn-LDHs and MgAl-LDHs were established and calculated by using density functional theory (DFT). The results shown that the doped-Mn can significantly change the electronic structure of the LDHs and improve its chemical activity. Compared with the MgAl-LDHs that without the doped-Mn, the HOMO-LUMO gap was smaller after doping. In addition, the -OH and Al on the laminates were also activated to improve the adsorption property of the LDHs. Besides, the doped-Mn existed as a novel active site. On the other hand, the MgAlMn-LDHs with the doped-Mn, the increased of the binding energy, as well as the decreased of the ion exchange energy of interlayer Cl⁻, making the ability to arsenate removal had been considerably elevated than the MgAl-LDHs. Furthermore, there is an obvious coordination covalent bond between arsenate and the laminates of the MgAlMn-LDHs that with the doped-Mn.     

大窑湾疏浚水环境要素变化特征及其相关关系

根据大窑湾后６个泊位疏浚工程本底调查和疏浚监测结果，借助因子分析探讨了疏浚前后水环境要素的变化特征及相关关系，找出了控制污染物分布的主要因子，评价了疏浚对海洋环境的影响。     

植物叶表尘及重金属对城市大气颗粒物污染的指示与评估

城市大气颗粒物污染问题日渐突出,目前主要依靠大气站点的直接观测数据反映污染的即时状况,而植物叶表尘及重金属的监测为评价大气颗粒物阶段性污染状况提供了新的途径.本研究通过分析北京交通带和公园共7个样点的臭椿(Ailanthus altissima)、槐(Sophora japonica)、北京杨(Populus beijingensis)、榆树(Ulmus pumila)、紫叶李(Prunus cerasifera f.atropurpurea)等5种常见绿化树种的叶表尘及重金属Cd、Cr、Cu、Mn、Ni、Pb、Zn含量,并计算尘金属综合累积指数(MAI),进而与邻近站点大气颗粒物观测数据对比并进行统计分析,尝试量化评价植物所处环境的大气颗粒物及尘重金属综合污染状况.结果表明:采用榆树叶表尘可量化评价大气可吸入颗粒物PM10的月均质量浓度,相对误差为1.2%~10.6%;臭椿叶表尘可量化评价大气细颗粒物PM2.5的月均质量浓度和月均空气质量指数(AQI),相对误差分别为0.18%~3.7%和0.26%~5.7%.MAI值可指示大气尘重金属综合污染状况,本研究中京承高速和朝阳公园大气尘重金属综合污染较重,其次为念坛公园、望京公园和玉蜓桥,最轻为岳各庄桥和麋鹿苑.     

废纸造纸废水结垢原因及防治对策研究

针对无锡某废纸造纸企业产生的污水经厌氧-好氧-化学混凝处理后,出水在放流池产生结垢现状,对各段污水中主要离子浓度进行跟踪分析,并对结垢的组分、结垢原因、机理和防治结垢对策进行了探讨。结果表明:垢样的主要成分为CaCO3;污水中含有较高浓度的钙离子和碳酸氢根离子是导致结垢的主要原因,较高的水温、pH值、流速、流动状态、池壁的粗糙程度以及PAC的投加对结垢也有一定的影响;最佳防治对策为使用Ca(OH)2+PAM代替PAC+PAM混凝,保证COD达标排放同时,也解决了出水结垢问题。