尿素基纤维的制备及对水中Cu2+和Cd2+的吸附

以棉纤维为原料,经氯化和取代反应,制得尿素基纤维并用于水中Cu^2＋和Cd^2＋的吸附,考察了各种因素对吸附效果的影响。尿素基纤维对Cu^2＋和Cd^2＋的吸附可用Langmuir等温吸附方程描述,吸附过程可看成单层吸附。较佳吸附条件：重金属离子溶液pH为5,流量为7mL／min。用过的尿素基纤维经2mol／L的盐酸洗脱再生后,对Cu^2＋的吸附、解吸、再吸附的性能良好,可重复使用。     

不同小叶章湿地H2S和COS的排放通量研究

利用静态箱/气相色谱法,观测了小叶章沼泽化草甸和小叶章典型草甸两种湿地类型中H2S和COS在生长季(5-9月)的释放动态,结果表明:在两种小叶章湿地中,H2S和COS的排放通量均具有明显的季节和日变化规律.在小叶章沼泽化草甸中H2S和COS的平均释放通量分别为0.34μg·m-2·h-1和-0.29μg·m-2·h-1;小叶章典型草甸H2S和COS的平均释放通量分别为0.14μg·m-2·h-1和-0.20μg·m-2·h-1;小叶章沼泽化草甸H2S和COS的平均释放通量均高于小叶章典型草甸.在生长季两种小叶章湿地均能向大气释放H2S,对COS则表现为从大气中吸收.小叶章的生长过程对H2S和COS的排放影响显著,在小叶章生长旺盛期,H2S出现排放峰值,COS出现吸收高峰.     

利用隆线溞趋光行为检测水体中五氯酚钠和镉的研究

采用自主选育的隆线溞单克隆体作为试验生物,研究了五氯酚钠(PCP-Na)和镉对隆线溞趋光指数的影响,并与急性毒性试验方法进行了比较.结果表明,在试验浓度范围内,水溞的趋光指数分别随五氯酚钠和镉浓度的升高而降低,呈极显著线性关系,说明隆线溞趋光指数的变化可以指示水体中这2种毒物的生物有效浓度.PCP-Na使隆线溞趋光指数(3h)发生显著改变的下限浓度为0.18 mg·L～,远低于LC50(96 h)(0.59 mg·L-1),上限浓度大于3.20 mg·L-1,也远高于LC50(24h)(0.73 mg·L-1),表明隆线溞趋光指数法比急性毒性试验法的灵敏度高,检测范围大,耗时短.在试验溶液范围内,五氯酚钠和镉之间不存在明确的相互作用关系.     

LB复合膜选择性检测水中痕量镉离子的方法研究

开发了一种利用LB复合膜选择性地检测水中痕量镉离子的技术方法,研究了最佳LB复合膜检测器的制作条件.用表面活性剂十二烷基-(2-噻唑偶氮)间苯二酚(DTAR)作显色剂,对乙烯基硬脂酸盐(PVS)、十八烷基异丁烯酸盐(PMOA)、乙烯基-N-氨基甲酸十八烷基酯(PVOC)和顺丁烯二酸酐-1-十八烯(PMO)4种聚合物进行了强度实验,得出稳定的检测器结构,即偶数层DTAR上附着单层PVOC的LB复合膜.经过灵敏度实验,制作出最佳LB复合膜检测器DTAR6-PVOC1,在pH为7.5,温度40℃且搅拌的反应条件下,该检测器可以在10 min之内检出10-7mol/L镉,并可目视定性及半定量检测出水中痕量镉离子.水中可能共存的离子中只有CU2+和Zn2+会干扰镉离子的检测,需要抑制.      

模拟油田采出水中硫化氢的脱除研究

硫化氢是油气田伴生气中的有害组分。在含硫油气田的采出水中,硫化氢的存在对于安全生产和和油田环境均会产生危害。采出水经处理后通常需作为地层回注水使用,由于油气生产的特殊性,常用的硫化氢脱除方法在使用中受到限制,探索适合于油气田生产的水处理方法十分必要。本文探讨了通常可用于油田水中硫化氢脱除的各种方法,对比了各类方法的优缺点,提出以次氯酸钠为主要脱硫剂的水处理方法,通过对模拟采出水的室内试验,证明次氯酸法可以快速有效地去除采出水中的硫化氢,并提出了消除过量氧化剂的后续处理方法。实验表明经处理后的水质可以达到油气田回注水质要求,处理成本较低。     

Cancer and Non-Cancer Health Risk from Eating Cassava Grown in Some Mining Communities in Ghana

Food crops such as cassava, cocoyam and other tuber crops grown in mining communities uptake toxic or hazardous chemicals such as arsenic, and cadmium, from the soil. Cassava is a stable food for Ghanaians. This study evaluated human health risk from eating cassava grown in some mining communities in Ghana such as Bogoso, Prestea, Tarkwa and Tamso, which are important mining towns in the Western Region of Ghana. The study evaluated cancer and non-cancer health effects from eating cassava grown in the study areas in accordance with US Environmental Protection Agency’s Risk Assessment guidelines. The results of the study revealed the following: cancer health risk for Tamso, 0.098 (RME – Reasonable Maximum Exposure) and 0.082 (CTE – Central Tendency Exposure). This means that approximately 10 and 8 out of 100 resident adults are likely to suffer from cancer related cases by RME and CTE parameters respectively. For Prestea, we have 0.010 and 0.12, which also means that approximately 1 out of 100 and 10 resident adults out of 100 are also likely to suffer from cancer related diseases by RME and CTE parameters. The results of the study obtained were found to be above the acceptable cancer risk range of 1× 10⁻⁶ to 1× 10⁻⁴, i.e., 1 case of cancer out of 1 million or 100,000 people respectively.     

Biomonitoring in the Boulder River Watershed, Montana, USA: Metal Concentrations in Biofilm and Macroinvertebrates, and Relations with Macroinvertebrate Assemblage

Portions of the Boulder River watershed contain elevated concentrations of arsenic, cadmium, copper, lead, and zinc in water, sediment, and biota. We measured concentrations of As, Cd, Cu, Pb, and Zn in biofilm and macroinvertebrates, and assessed macroinvertebrate assemblage and aquatic habitat with the objective of monitoring planned remediation efforts. Concentrations of metals were generally higher in downstream sites compared with upstream or reference sites, and two sites contained metal concentrations in macroinvertebrates greater than values reported to reduce health and survival of resident trout. Macroinvertebrate assemblage was correlated with metal concentrations in biofilm and macroinvertebrates. However, macroinvertebrate metrics were significantly correlated with a greater number of biofilm metals (8) than metals in invertebrates (4). Lead concentrations in biofilm appeared to have the most significant impact on macroinvertebrate assemblage. Metal concentrations in macroinvertebrates were directly proportional to concentrations in biofilm, indicating biofilm as a potential surrogate for monitoring metal impacts in aquatic systems.     

碳酸镁与镉离子的吸附和沉淀作用研究

以碳酸镁为吸附剂,在镉离子初始浓度为0~6 mmol/L,初始pH值为4和7的条件下,研究了碳酸镁与镉离子的吸附与沉淀作用。结果表明,由于碳酸镁的溶解及与体系中氢离子的中和,碳酸镁—镉体系的最终pH值为10.4左右;体系的平衡pH值随着镉离子初始浓度的增加而减小;体系中镉的平衡浓度随着初始镉离子浓度的增加缓慢上升;碳酸镁对镉的吸附等温线为折线型,不符合Freundlich和Langmuir模型,符合伪二阶吸附动力学模型。结合碳酸镁吸附镉前后固相表征的结果,说明碳酸镁与镉离子的作用机制随着镉离子浓度的增加,从离子交换发展为离子交换和表面配位反应并存,最后表现为表面沉淀。     

酸性洗涤塔-生物滤塔-生物曝气池组合工艺处理恶臭气体NH3和H2S

采用酸性洗涤塔、生物滤塔和生物曝气池的组合工艺处理NH3、H2S恶臭混合气体,研究表明,该组合工艺对NH3和H2S有很好的去除效果,在进气流量为35 L/min,喷淋量45 L/h时,NH3进气浓度50.15~525.4 mg/m3,H2S进气浓度10.23~110.36 mg/m3时,NH3单一进气去除率稳定在99%以上,H2S单一进气去除率90%以上。混合进气后,NH3去除率几乎为100%,H2S的去除率提高至98%以上。在一定的浓度范围内,NH3和H2S之间的相互作用对两者的去除效果没有明显的影响,而且起到了相互促进降解的作用。同时,进气流量和填料层高度都会影响NH3、H2S的去除率。系统对进气容积负荷变化的缓冲能力强,在偶尔超负荷条件下运行并不能使系统崩溃,并且微生物对高负荷逐渐表现出适应性。大部分溶于水的氨由生物曝气池去除,去除率达到96.9%。     

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。