新型二氧化铅电极处理染料废水

利用高压塑片法制备掺杂镧和活性炭以及聚四氟乙烯(PTFE)的新型二氧化铅电极,采用X衍射(XRD),循环伏安曲线(CV),扫描电镜(SEM)等手段对电极性能进行表征,研究了其电催化处理有机染料废水(亚甲基蓝)的降解效果,并对反应机理进行了相关研究。研究表明,该电极具有良好的抗腐蚀能力,对亚甲基蓝具有较好的降解效果。通过与普通二氧化铅电极比较,该电极在染料脱色和去除COD方面都有较明显优势,显示出较好的工业应用前景。     

生物炭修复Cd,Pb污染土壤的研究进展

随着矿产开采、冶炼等工业活动以及污水灌溉、施用污泥和劣质化肥等农业活动的进行,Cd,Pb等有害重金属不断进入农业环境中,对农田、菜地等造成污染。生物炭作为重要的土壤改良剂,在对Cd,Pb污染土壤的修复中表现出巨大的潜力。从生物炭的特性及制备、修复效果及其影响因素、修复机理等方面,对近年来国内外有关生物炭修复Cd,Pb污染土壤的研究成果和现状进行了总结,并对生物炭修复Cd,Pb污染土壤的发展前景和未来研究方向进行了展望。     

磷酸活化-微波热解改性污泥对镉的吸附性能

以城市污水处理厂剩余污泥为原料,利用磷酸活化-微波热解制取改性污泥。以此污泥作为吸附剂,对含Cd2+废水进行了吸附实验研究。考察了溶液反应时间、Cd2+浓度、pH值和吸附剂用量对镉吸附去除效果的影响;利用等温吸附实验作出吸附等温线,并考察了改性污泥吸附剂吸附Cd2+的动力学方程。实验结果表明,改性污泥对Cd2+有良好的吸附性能,吸附最佳pH值为6.0,吸附较好地符合一级动力学吸附模型和Langmuir-Freundlich等温吸附方程,吸附为物理吸附,吸附反应发生12 h后达到吸附平衡。     

Accumulation and quantitative estimates of airborne lead for a wild plant (Aster subulatus)

Foliar uptake of airborne lead is one of the pathways for Pb accumulation in plant organs. However, the approximate contributions of airborne Pb to plant organs are still unclear. In the present study, aerosols (nine-stage size-segregated aerosols and total suspended particulates), a wild plant species (Aster subulatus) and the corresponding soils were collected and Pb contents and isotopic ratios in these samples were analyzed. Average concentration of Pb was 96.5 ± 63.5 ng m⁻³ in total suspended particulates (TSP) and 20.4 ± 5.5 ng m⁻³ in the fine fractions of size-segregated aerosols (SSA) (<2.1 μm), higher than that in the coarser fractions (>2.1 μm) (6.38 ± 3.71 ng m⁻³). Enrichment factors show that aerosols and soils suffered from anthropogenic inputs and the fine fractions of the size-segregated aerosols enriched more Pb than the coarse fractions. The order of Pb contents in A. subulatus was roots > leaves > stems. The linear relationship of Pb isotope ratios (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb) among soil, plant and aerosol samples were found. Based on the simple binary Pb isotopic model using the mean ²⁰⁶Pb/²⁰⁷Pb ratios in TSP and in SSA, the approximate contributions of airborne Pb into plant leaves were 72.2% and 65.1%, respectively, suggesting that airborne Pb is the most important source for the Pb accumulation in leaves. So the combination of Pb isotope tracing and the simple binary Pb isotope model can assess the contribution of airborne Pb into plant leaves and may be of interest for risk assessment of the exposure to airborne Pb contamination.     

Cobalt-induced oxidative stress in brain, liver and kidney of goldfish Carassius auratus

Cobalt is an essential element, but at high concentrations it is toxic. In addition to its well-known function as an integral part of cobalamin (vitamin B₁₂), cobalt has recently been shown to be a mimetic of hypoxia and a stimulator of the production of reactive oxygen species. The present study investigated the responses of goldfish, Carassius auratus, to 96 h exposure to 50, 100 or 150 mg L⁻¹ Co²⁺ in aquarium water (administered as CoCl₂). The concentrations of cobalt in aquaria did not change during fish exposure. Exposure to cobalt resulted in increased levels of lipid peroxides in brain (a 111% increase after exposure to 150 mg L⁻¹ Co²⁺) and liver (30-66% increases after exposure to 50-150 mg L⁻¹ Co²⁺), whereas the content of protein carbonyls rose only in kidney (by 112%) after exposure to 150 mg L⁻¹ cobalt. Low molecular mass thiols were depleted by 24-41% in brain in response to cobalt treatment. The activities of primary antioxidant enzymes, superoxide dismutase (SOD) and catalase, were substantially suppressed in brain and liver as a result of Co²⁺ exposure, whereas in kidney catalase activity was unchanged and SOD activity increased. The activities of glutathione-related enzymes, glutathione peroxidase and glutathione-S-transferase, did not change as a result of cobalt exposure, but glutathione reductase activity increased by ∼40% and ∼70% in brain and kidney, respectively. Taken together, these data show that exposure of fish to Co²⁺ ions results in the development of oxidative stress and the activation of defense systems in different goldfish tissues.     

PVA降解混合菌系生长和产酶的营养条件分析

研究碳源、氮源以及不同金属离子对PVA降解混合菌系生长和产酶的影响。结果表明,混合菌系生长过程中无机氮源优于有机氮源;补充碳源可促进混合菌系的生长,但酶活比不添加时稍有降低。金属离子对酶活影响的正交实验表明Mg2＋浓度影响最大,其次是Fe2＋和K＋浓度,Ca2＋、Mn2＋、Zn2＋和Cu2＋浓度影响较小;最佳浓度分别为Mg2＋0.05 g/L、Fe2＋0.04 g/L、K＋2 g/L和Ca2＋0.05 g/L。     

利用含铬废水和含铅废水制备铬黄

利用净化后的含铬废水和含铅废水制备铬黄.采用沉淀法对废水进行净化预处理,最佳工艺条件:100mL含铬废水中加入20 g Na_2CO_3,及10 mL H_2O_2,用NaOH调节含铬废水pH为10.00;用NaOH调节含铅废水pH为2.65.将净化后的10 mL含铬废水和25 mL含铅废水混合,在55-60℃条件下反应10 min,合成的铬黄达到GB/T 3184-2008<铬酸铅颜料和钼铬酸铅颜料>的质量标准.经重金属吸附剂处理Pb~(2+)后铬黄合成滤液中的Cr~(6+)和Pb~(2+)质量浓度均达到GB8978-1996<污水综合排放标准>的指标.     

中国典型河湖水体铅的水生生物安全基准与生态风险评价

采用物种敏感度排序法(SSR)对我国铅的淡水水生生物安全基准进行推导,并以太湖为例进行了流域水生生物安全基准推导。对于难以获得的本土生物毒性数据,开展了相应的毒性试验。获得了我国国家与太湖流域铅的水生生物安全基准值,基准最大浓度(CMC)分别为63.92、104.26μg·L-1,基准连续浓度(CCC)分别为1.21、4.06μg·L-1。同时,对我国主要河流以及太湖流域进行了铅的生态风险评价,联合概率曲线法显示影响5%水生生物种类的概率分别为66.22%和43.19%,熵值法则显示中国主要河流存在较大的铅暴露风险,因此,我国铅的潜在生态风险较大,主要河流与太湖流域存在铅污染问题。     

铅和得克隆联合暴露对斑马鱼胚胎的神经毒性作用

以斑马鱼(Danio rerio)为研究对象,探讨铅(Pb)、得克隆(DP)及二者联合急性暴露对斑马鱼胚胎的神经毒性作用。结果表明,Pb(5、20μg·L~(-1))和DP(15、60μg·L~(-1))单独暴露均会引起斑马鱼自主运动频率增加,触摸反应能力和自由游泳活力下降,并且抑制初级运动神经元的生长,加剧尾部细胞凋亡。但与20μg·L~(-1)Pb单独暴露相比,高剂量联合暴露(20μg·L~(-1)Pb+60μg·L~(-1)DP)使斑马鱼的自主运动频率显著降低(P0.05),触摸反应能力和自由游泳活力显著增强(P0.05),初级运动神经元轴突长度显著增加(P0.05),尾部细胞凋亡减少。与5μg·L~(-1)Pb单独暴露相比,低剂量联合暴露(5μg·L~(-1)Pb+15μg·L~(-1)DP)也显著减少斑马鱼尾部的细胞凋亡(P0.05)。上述结果表明,Pb或DP单独暴露对斑马鱼均可引起神经毒性作用;但二者联合暴露对斑马鱼自主运动、触摸反应以及自由游泳活力的影响则表现为拮抗作用。     

工业废水中多金属离子的吸附净化

以含有Si、Al、Ca、C元素的矿物材料作为基质,经特定条件处理后造粒成型加工成轻质多孔Si-Al-Ca-C结构的吸附材料。研究了该吸附材料对工业废水中多种金属离子的吸附性能,探讨了影响吸附性能的因素。研究结果表明,在一定条件下,Si-Al-Ca-C吸附材料对工业废水中Al3+、Ca2+、Mn2+、Cu2+、Fe3+、Mg2+、As3+和Zn2+的净化率分别高达99.34%、99.82%、98.26%、98.16%、97.76%、97.01%、100%和89.09%。金属离子残留浓度分别为0.152、0.07、0.012、0.02、0.119、0.311、0和0.259 mg/L,均低于国家污水综合排放标准(GB8978-1996)一级标准。