化学混凝法去除稠油废水中的硅

以新疆油田稠油废水为研究对象,采用化学混凝除硅方法对稠油废水进行处理。实验结果表明:采用锌复合混凝剂的混凝、软化及镁剂除硅相结合的方法具有较好的除硅效果。确定了最佳除硅配方:NaOH的加入量为500~600mg/L,除硅剂MgCl2.6H2O的加入量为700~800mg/L,锌复合混凝剂加入量为100~150mg/L,处理后废水中SiO2的质量浓度小于50mg/L,达到热采锅炉的用水标准。     

Exposure Programme on Atmospheric Corrosion Effects of Acidifying Pollutants in Tropical and Subtropical Climates

Many national exposure programmes have been performed in tropical and subtropical climates during the last 50 years. However, ambitious programmes involving more than a few countries are scarce. In this paper a recently formed network of test sites is described involving 12 test sites in Asia (India, Vietnam, Thailand, Malaysia and China including Hong Kong) and four test sites in Africa (South Africa, Zambia and Zimbabwe). This effort is part of the 2001–2004 Swedish International Development Agency (SIDA) funded Programme on Regional Air Pollution in Developing Countries (RAPIDC). Corrosion attack after one (2002–2003) year of exposure (carbon steel, zinc, copper, limestone and paint coated steel) are presented together with environmental data (SO₂, NO₂, HNO₃, O₃, particles, amount and pH of precipitation, temperature and relative humidity) for all the test sites. The obtained corrosion values are substantially higher than expected for limestone, higher than expected for carbon steel and lower than expected for zinc compared to values calculated using the best available dose–response functions.     

THE IMPACT OF URBANIZATION ON THE DISTRIBUTION OF HEAVY METALS IN BOTTOM SEDIMENTS OF THE SADDLE RIVER1

ABSTRACT: A three-year study has been conducted on a 4.6 mile stretch of the Saddle River near Lodi, New Jersey. The primary objectives of this investigation were (1) to provide baseline information on the concentration and distribution of heavy metals in bottom sediments of the Saddle River; (2) to qualitatively evaluate which parameters affect this distribution; and (3) to determine the effect of urbanization on the concentration and distribution of these materials. Significant enrichments of several heavy metals were observed in bottom sediments of the lower Saddle River near Lodi, New Jersey, as compared to the upper Saddle River. Attempts to correlate metal concentrations in bottom sediments with chemical-oxygen demand were not successful in demonstrating a relationship between these two factors. Metal concentrations were found to be strongly dependent upon particle size. In general, metal concentrations in bottom sediments increased with decreasing partical diameter. However, metals enrichment was observed to be considerably greater in the larger sediment fractions studied (>420μ) than the smaller sediment fractions as one proceeded downstream through the urban area. Since the larger sediment fractions are least effected by scour and transport they may best reflect the effect of urbanization on the distribution of heavy metals over an extended period of time at a given location.     

磁微球负载硝基锌卟啉光催化剂的制备及催化性能研究

以氯化血红素为原料,制备了磁负载的硝基锌卟啉光催化剂.同时,利用热重分析仪(TG)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和振动磁强计(VSM)对催化剂进行了表征,发现制备的催化剂负载率为32.06%,催化剂为粒径均一的球形壳-核结构,具有良好的磁性.其次,研究了催化剂的催化降解性能.结果表明,磁负载硝基锌卟啉光催化剂在可见光下,对水中的双酚A(BPA)、对硝基苯酚(PNP)等均有90%以上的去除率;对于活性红染料废水的降解也取得了83.67%的降解率.自由基捕获实验证明,电子(e-)、羟基自由基(·OH)、空穴(h+)和氧自由基(O-·2)是降解反应中重要的活性物种.最后通过GC-MS等手段对降解机理进行了研究.     

模拟黑麦草根系有机酸参与下炼锌废渣对斑马鱼抗氧化酶和神经毒性的影响

为评价多金属矿山废渣堆场生态修复过程中,废渣在先锋修复植物根系分泌的机酸参与下浸出液对周边环境生物的影响.以斑马鱼（Danio rerio）为受试生物,通过模拟添加典型先锋植物（黑麦草）根系分泌的有机酸（草酸和酒石酸）处理贵州威宁土法炼锌废渣,以废渣浸出液对受试生物抗氧化酶和乙酰胆碱酯酶（AchE）的不同响应为评价指标,研究各处理组对斑马鱼抗氧化系统、神经系统及组织学的影响.结果表明,两种有机酸的参与均会不同程度地降低炼锌废渣浸出液的pH,并导致废渣释放出更多重金属;暴露于有机酸参与的废渣浸出液14 d后,受试生物组织中的抗氧化酶受到显著影响,并因无法克服长时间的氧化应激最终引起丙二醇（MDA）在组织中累积;有机酸参与下废渣浸出液对斑马鱼具有明显的神经毒性,长时间暴露后受试生物出现游动迟缓、呼吸慢和鳃盖张合频率降低的现象;鳃组织存在上皮细胞水肿、增生或脱落、鳃丝充血和鳃小片扭曲或断裂的现象,而肌肉组织中出现更多肌纤维核增大、固缩和碎裂的现象.综上,选用适生性和耐受性较强、根系发达且有机酸分泌量较大的先锋植物来修复多金属废渣场地将可能促进废渣中重金属的释放并引起环境生物抗氧化系统和神经系...     

纳米氧化锌对大型溞肠道组织毒性效应及机理研究

研究了不同浓度纳米氧化锌（ZnONP）及其在水中释放的对应浓度的Zn²⁺溶液对大型溞（Daphnia magna）肠道组织显微和亚显微结构的影响,探讨了ZnONP对大型溞的肠道组织毒性效应特征和作用机理.结果表明,0.3 mg·L^-1-Zn²⁺组（Zn²⁺浓度0.170 mg·L^-1）和0.3 mg·L^-1 ZnONP溶液皆对大型溞的肠道造成损伤,主要导致大型溞中肠与直肠之间的连接处发生扭曲,其中ZnONP对肠道组织结构弯曲影响最为明显,0.3 mg·L^-1 ZnONP组引起大型溞个体最大肠道弯曲率高达42%.大型溞肠道组织HE染色结果显示,ZnONP暴露会造成大型溞肠道上皮组织断裂、胞间连接空泡化、纹状缘模糊及杯状细胞脱落等,而相对应浓度Zn²⁺组的毒性较弱.电子显微镜下对大型溞肠道组织亚显微结构观察发现,0.3 mg·L^-1 ZnONP处理组大型溞肠道上皮细胞组织出现微绒毛排列紊乱、脱落、溶解,上皮细胞松散,线粒体双层膜结构不完整,嵴溶解消失,核糖体增多等现象.0.3 mg·L^-1-Zn²⁺组大型溞肠道组织上皮细胞有损伤,但整体结构基本完整.从ZnONP和对应的Zn²⁺所产生的毒性效应特征和各组大型溞机体中Zn元素含量的测定分析,ZnONP对大型溞造成的肠道组织损伤不仅与其释放的Zn²⁺引起的毒性有关,更可能与大型溞对颗粒物摄取的方式或ZnONP在体内的积累量、排泄速率和作用的细胞器等有关.因此,ZnONP对肠道组织毒性效应产生的分子机制还需要 进一步研究.     

土壤中镉、锌离子的单一及竞争吸附研究

采用等温吸附法探讨了重金属镉、锌在青岛地区3种主要土壤(棕壤、潮土和砂浆黑土)中的吸附特征.结果表明,在质量浓度为20～500 mg/L的单一重金属等温吸附试验中,棕壤和潮上对Cd~(2+)、Zn~(2+)的吸附量相近,而黑土对Cd~(2+)、Zn~(2+)的吸附量明显高于棕壤和潮土.Cd~(2+)、Zn~(2+)的双组分竞争吸附表明,3种上壤对Cd~(2+)、Zn~(2+)的吸附量与其单独存在下的情形相比都有所下降.质量浓度分别为20～500mg/L的两种重金属元索等馈竞争吸附时,这3种土壤对Cd2+的吸附量比对Zn~(2+)的大.非等量竞争吸附试验的结果表明,3种土壤中,500mg/L的Zn~(2+)对100 mg/L的Cd~(2+)吸附量的影响均比同浓度的Cd~(2+)对Zn~(2+)的影响大.用Langmuir和Freundlich方程对这两种重金属离子的等温吸附试验数据进行拟合,均呈极显著相关关系.     

铅锌尾矿废弃地的化学性质研究

凡口铅锌尾矿废弃地的不同区位及不同深度的尾矿中铅锌含量存在着较大的差异 ,总锌为 70 3～ 19657mg/ kg、总铅 10 4 13～ 94 988mg/ kg。正常尾矿中 ,有效态锌含量达到 151.6～ 84 1.7mg/ kg,有效态铅含量很低 ( 0 .75～ 2 .50 mg/ kg) ,有机质、总氮、有效磷及速效钾等营养物质缺乏。当尾矿酸化后 ,p H降低 ,有效态 Pb、Zn含量升高 ,有效锌达到 175.8～ 2 82 8.0 mg/ kg,有效铅含量最高为 10 0 .0 mg/kg,而有机质、总氮和有效磷为零 ,使尾矿更加贫瘠。在尾矿库的边缘区位和尾矿表面的覆盖土壤区位 ,基质中营养物质含量增加 ,但是营养状况的改善又引起了有效态的 Pb、Zn含量升高。