Plant species coexistence alleviates the impacts of lead on Zea mays L.

Whether plant coexistence can reduce the impacts of lead (Pb) on crops in agroecosystems has not been well understood. We conducted a factorial experiment to investigate the effects of weeds coexisting with maize (Zea mays L.) on Pb accumulation in maize and soil microbes at two Pb levels (ambient and 300 mg/kg). Elevated Pb tended to increase the Pb concentration in maize and decreased soil microbial activity (indicated by the average well color development, AWCD), functional group diversity, as well as arbuscular mycorrhizal (AM) colonization and vesicle number of maize. Compared to the monoculture, weeds coexisting with maize reduced the Pb concentrations in the root, leaf, sheath and stem of maize at both seedling and mature stages. In maize-weed mixtures, soil microbial activity and functional group diversity tended to increase for both Pb treatments relative to the monoculture. Furthermore, principal component analysis revealed that the soil microbial community structure changed with the introduction of weeds. The highest Pb accumulation in weeds occurred for the elevated Pb treatment in a three species mixture. The results suggest that multiple plant species coexistence could reduce lead accumulation in crop plants and alleviate the negative impacts on soil microbes in polluted land, thereby highlighting the significance of plant diversity in agroecosystems.     

全自动阵列离子迁移谱仪连续监测挥发性有机化合物

为了拓宽离子迁移谱仪的检测范围、提高化合物的识别准确度,研制了一套阵列离子迁移谱仪,该仪器基于63 Ni源正离子模式、63Ni源负离子模式和真空紫外灯光电离模式的组合电离源,可以连续监测空气中挥发性有机化合物.仪器采用全自动的采样进样系统,同时检测了二甲基亚砜的正离子和二氯甲烷的负离子,实现了正负离子的同时检测.通过对阵列离子迁移谱图的综合解析,识别了63Ni源正离子模式下难以鉴别的丙烯腈、间二甲苯和丙酮.连续4 d定量测定丙酮样品,结果表明仪器对丙酮的线性检测范围为2个数量级,线性相关系数R优于0.995,相对标准偏差控制在4.0%～18.3%.采用动态跟踪法,连续24 h在线监测了模拟泄漏的丙烯酸甲酯,监测结果直接反映了其泄漏的时间和浓度.     

煤气湿式电除尘器洗涤水循环利用的研究

采用化学混凝、絮凝以及离子交换软化的方法处理钢厂煤气湿式电除尘器(ESP)洗涤废水,设计出小型、高效的废水处理及回用系统。以废水的SS、总硬度、总碱度为主要因子,在浓度分别为350,365,315 mg/L的条件下,经过两个主要单元的处理后,浓度可达7,75,70 mg/L,达到回用标准,降低了运行成本,环境效益显著。     

Poly[β-(1→4)-2-amino-2-deoxy-D-glucopyranose] based zero valent nickel nanocomposite for efficient reduction of nitrate in water

Chemical reduction of nitrate using metal nanoparticles has received increasing interest due to over-dependence on groundwater and consequence health hazard of the nitrate ion. One major drawback of this technique is the agglomeration of nanoparticles leading to the formation of large flocs. A low cost biopolymeric material, poly [β-(1 → 4)-2-amino-2-deoxy-D-glucopyranose] (β-PADG) obtained from deacetylated chitin was used as stabilizer to synthesize zero valent nickel (ZVNi) nanoparticles. The β-PADG-ZVNi nanocomposite was characterized using infra red (IR), UV-Vis spectrophotometric techniques and Scanning Electron Microscope (SEM). The morphology of the composite showed that β-PADG stabilized-ZVNi nanoparticles were present as discrete particles. The mean particle size was estimated to be (7.76 ± 2.98) nm and surface area of 87.10 m²/g. The stabilized-ZVNi nanoparticles exhibited markedly greater reactivity for reduction of nitrate in water with 100% conversion within 2 hr contact owing to less agglomeration. Varying the β-PADG-to-ZVNi ratio and the ZVNi-to-nitrate molar ratio generally led to a faster nitrate reduction. About 3.4-fold difference in the specific reaction rate constant suggests that the application of the β-PADG-stabilizer not only increased the specific surface area of the resultant nanoparticles, but also greatly enhanced the surface reactivity of the nanoparticles per unit area.     

废旧锂电池电极活性材料真空热解固氟研究

以废旧锂离子电池电极活性材料为研究对象,在真空热解过程中加入CaO作为固氟剂,用以吸收电极活性材料在真空热解的回收工艺中产生的氟磷化合物,能有效减轻二次污染。研究了温度、CaO添加量、停留时间等热解条件对真空热解固氟效果的影响。结果表明固氟效果随温度的增加而增加,在温度500℃以上变化不大,并略有下降;CaO添加量对固氟效果有促进作用,30%可达到很高的固氟效果;30 min的停留时间对于含氟化合物的分解已经足够。得到CaO固氟工序的最佳操作参数:CaO添加量30%左右,温度500~600℃,停留时间30 min。     

东北森林地区与国内外其它地区地表水中主要离子浓度及酸中和能力的比较

几十年来,中国二氧化硫排放量持续增长同多数地区一样,东北森林地区酸性物质沉降量一直较高。资料显示,在中俄边境及中国与北朝鲜边境的大片森林地区岩床普遍不易风化且钙矿物含量低,这与挪威南方七、八十年代遭受大范围的地表水酸化时的情形类似。为探明东北森林地区地表水是否存在酸化潜势,本研究对东北森林地区4个地表水中主要离子浓度与英国、中欧地区、挪威南部、西部、中国南方等地资料数据进行了比较,发现东北森林地区地表水中具有较高的酸中和能力,即具有较大抵御未来地表水酸化的能力。     

Arsenic in Drinking Water and Its Removal

Abstract

Superfluous arsenic in drinking water can do harm to human health. In this paper, a broad overview of the available technologies for arsenic removal has been presented on the basis of literature survey. The main treatment methods included coagulation-sedimentation, adsorption separation and ion exchange, membrane technique, which have both advantages and disadvantages. It concluded that the selection of treatment process should be site specific and prevailing conditions and no process can serve the purpose under diverse conditions as each technology has its own limitations. In order to gain good results, some methods should be improved.     

基于水化学与硫同位素的卡林型金矿区岩溶水文地球化学特征及控制因素

采矿活动通过抽排改变地下水水位和流动条件,促进了地下水与含水层岩石之间的相互作用,同时矿山排水排入地表水系,从而影响整个岩溶水系统的水文地球化学过程.基于水文地球化学和δ³⁴ S同位素,揭示了典型卡林型金矿区及其周边矿山废水、岩溶地下水、地表水等水文地球化学过程、特征及其主要控制因子.结果表明,未受金矿开采活动影响的地下水和地表水的丰、枯水期水化学组分主要受灰岩和白云质灰岩风化作用控制,离子以Ca²⁺、Mg²⁺和HCO₃^-为主,水化学类型均为Ca-HCO₃型.而矿山废水及其下游受纳水体受碳酸盐和硅酸盐矿物溶蚀与离子交换作用影响,离子以Ca²⁺、Mg²⁺、Na⁺和SO₄^2-为主,水化学类型由Ca-HCO₃型逐步演化为Ca-SO₄型.受矿山开采影响的各类水体中SO₄^2-是特征组分,SO₄^2-浓度在井下呈现从上至下逐渐降低的显著规律.未受矿山废水影响的地下水和地表水δ³⁴ S值偏正,SO₄^2-主要来源于雄黄矿的氧化,而矿山废水及其下游受纳水体δ³⁴ S值偏负,SO₄^2-主要受雄黄矿氧化和大气降水两个端元混合作用的影响,黄铁矿也有一定贡献.同时,各类水体的NO₃^-源于农业化肥施用和农村生活污水直排的输入.     

磁性离子印迹聚合物的制备及其对水中Pb(Ⅱ)的吸附

以铅离子为模板离子、乙二醇二甲基丙烯酸酯和偶氮二异丁腈为交联剂和引发剂、稀盐酸为洗脱剂,采用微波辅助反相乳液悬浮聚合法,制备了磁性离子印迹聚合物(MIIP),通过SEM、FTIR、XRD和BET技术对其进行了表征,并将其用于水中Pb(Ⅱ)的吸附.在初始质量浓度60 mg/L、溶液pH 6、吸附温度303 K、吸附时间6...     

钢渣-蒙脱石复合吸附剂对水中Cd~(2+)的吸附去除

研究了钢渣-蒙脱石复合吸附剂对废水中Cd2+的吸附性能,并探讨了影响吸附的因素和吸附机理.结果表明,钢渣蒙脱石质量比为1∶1的复合吸附剂对Cd2+的吸附效果优于钢渣及蒙脱石对Cd2+的单一吸附.当温度为25℃,废水pH=6~7时,1.2 g钢渣-蒙脱石复合吸附剂对100 mL Cd2+溶液(100 mg·L-1)吸附60 min后,Cd2+的去除率可达到96.99%.钢渣-蒙脱石复合吸附剂对镉离子的吸附反应符合二级动力学方程,可决系数为0.9991;符合Langmuir方程,可决系数为0.9725.对Cd2+的理论饱和吸附量为12.45 mg·g-1.溶液中Pb2+、Cu2+的存在会降低复合吸附剂对Cd2+的吸附量,且Cd2+受Cu2+的影响较大.吸附饱和的钢渣-蒙脱石颗粒材料用1 mol·L-1的氯化钠溶液再生效果好.