Polybrominated diphenyl ethers (PBDEs) and mercury in fish from lakes of the Tibetan Plateau

High mountains may act as cold traps for globally transported persistent organic pollutants (POPs) and mercury (Hg). In the present study, 60 fish samples were collected from eight alpine lakes across the Tibetan Plateau. Concentrations of polybrominated diphenyl ethers (PBDEs), total mercury (HgT) and methyl mercury (MeHg) were quantified in the fish muscle tissues to improve the understanding of pollution status and factors regulating the transport and fate of these contaminants on the Plateau. The results showed that lake-averaged ∑₁₄PBDEs concentration was between 0.09 ng g⁻¹ dw and 4.32 ng g⁻¹ dw, which was lower than those reported for European mountains. The total mercury concentration in individual fish ranged from 243 to 2384 ng g⁻¹ dw, and that of MeHg from 131 to 1610 ng g⁻¹ dw, which is much higher than those reported in other mountain fish. The spatial variation of PBDEs and mercury in the Plateau is largely controlled by the specific meteorological patterns.     

Polarity effect of pulsed corona discharge for the oxidation of gaseous elemental mercury

The effect of polarity on the oxidation of Hg⁰ was examined in the presence of O₂ via a pulsed corona discharge (PCD). The experimental result showed no difference in the energy yield of Hg⁰ oxidation at both positive and negative PCDs (∼8 μg Hg W h⁻¹ at following conditions: total flow rate = 2 L min⁻¹ (Hg⁰ = 50 μg N m⁻³, O₂ = 10%, and N₂ balance), temperature = 150 °C, and specific energy density = 5-15 W h N m⁻³). This suggests that the positive PCD process used to control gaseous air pollutants may play an essential key role in Hg⁰ oxidation because it consumes enough energy (∼15 W h N m⁻³) but an electrical precipitator could not because it consumes less energy (∼0.3 W h N m⁻³) to oxidize Hg⁰.     

Development of a hybrid microbial fuel cell (MFC) and fuel cell (FC) system for improved cathodic efficiency and sustainability: the M2FC reactor

In an effort to improve the efficiency and sustainability of microbial fuel cell (MFC) technology, a novel MFC reactor, the M2FC, was constructed by combining a ferric-based MFC with a ferrous-based fuel cell (FC). In this M2FC reactor, ferric ion, the catholyte in the MFC component, is regenerated by the FC system with the generation of additional electricity. When the MFC component was operated separately, the electricity generation was maintained for only 98 h due to the depletion of ferric ion in the catholyte. In combination with the fuel cell, however, the production of power was sustained because ferric ion was continually replenished from ferrous ion in the FC component. Moreover, the regeneration process of ferric ion by the FC produced additional energy. The M2FC reactor yielded a power density of up to 2 W m⁻² (or time-averaged value of approximately 650 mW m⁻²), density up to 20 times (or approximately six times based on time-averaged value) higher than the corresponding MFC system.     

改性糠醛渣吸附脱硫废水中钙离子

石灰石-石膏法烟气脱硫技术中石灰石利用率低导致钙流失严重,为实现脱硫废水中Ca2+的资源化利用,进行糠醛渣改性和Ca2+的吸附特性研究。实验结果表明,利用H3PO4改性后的糠醛渣对脱硫废水中Ca2+具有较高的吸附率;在振荡的前30 min吸附率上升极快,至90 min时基本达到平衡吸附量;对Ca2+浓度对吸附率影响研究结果表明,平衡吸附量与平衡浓度关系符合Langmuir等温吸附方程;在初始Ca2+浓度为300 mg/L的溶液中加入3 g吸附剂,温度30℃条件下振荡90 min,平衡吸附量为8.41 mg/g。     

Fe~(3+)和Cu~(2+)对饮用水氯消毒副产物三卤甲烷形成的影响

为了研究水中存在Br-的情况下,Fe3+和Cu2+对三卤甲烷(THMs)的生成及CHCl3、CHBr Cl2、CHBr2Cl、CHBr34种消毒副产物相对分布的影响,以腐殖酸模拟氯消毒过程中的前体物进行实验。结果表明,在p H为6、7和9 3种条件下,Fe3+抑制了THMs的生成,p H=6时只有CHCl3生成量随着Fe3+浓度的增加逐渐减少,其余3种消毒副产物均在增加,p H=7时4种消毒副产物浓度均减小并在Fe3+浓度为2 mg/L时生成量最低,p H=9时的生成趋势与p H=6时类似。Cu2+能促进THMs的生成,在p H为6、7和9时,当加入0.5 mg/L Cu2+时,THMs总量分别增加了16.7%、22.6%和2.5%,随着p H增加,THMs总量增加。在3种p H环境中,Cu2+对THMs生成的影响大于Fe3+,在偏酸性环境中,Fe3+影响THMs生成,产生的致癌风险高,当金属离子浓度为2.5 mg/L时,致癌风险相差最高为15%,在中性和偏碱性环境中,Cu2+影响THMs生成,产生的致癌风险高。     

高炉渣对Cd~(2+)的吸附性能

采用包头钢铁集团炼铁厂的高炉渣为吸附剂(粒径0.154 nm)对Cd2+进行吸附,运用SEM技术对吸附剂进行了表征,研究了初始Cd2+质量浓度、吸附剂加入量、吸附时间、吸附温度和废水pH对Cd2+去除率的影响,并探讨了吸附机理。表征结果显示:高炉渣吸附剂具有疏松多孔的特点,表面十分粗糙,比表面积较大。实验结果表明:当吸附温度为室温(28℃)、废水pH为7、初始Cd2+质量浓度为10 mg/L、吸附剂加入量为8 g/L、吸附时间为60 min时,Cd2+去除率达到98.55%;高炉渣对Cd2+的吸附符合拟二级动力学方程和Langmuir等温吸附模型,且吸附反应易发生。     

碱熔融—微波晶化法合成粉煤灰沸石及其对Cd2+的吸附

以粉煤灰为主要原料,采用碱熔融—微波晶化法合成粉煤灰沸石。采用XRD,SEM,TEM等技术表征了粉煤灰沸石的微观结构,并对其吸附Cd²⁺的性能进行了研究。表征结果显示,粉煤灰沸石主要由X型沸石、P型沸石和铝组成,粉煤灰沸石中有排列规则、呈蜂窝状的孔穴和孔道存在,其孔穴和孔道大小分布均匀,致密。粉煤灰沸石的比表面积为108.49 m²/g,平均孔径为3.779 nm,孔体积为0.221 mL/g。实验结果表明,在溶液pH为7、吸附时间30 min的最佳吸附条件下,Cd²⁺去除率均大于94%。粉煤灰沸石对Cd²⁺的吸附可很好地用二级动力学方程进行拟合,相关系数为0.999 99。可用Langmuir等温吸附模型描述该吸附过程,该吸附过程是单分子层吸附,主要是化学吸附,粉煤灰沸石对Cd²⁺的饱和吸附量为49.261 mg/g。     

贵阳市一居民区大气颗粒态汞的污染状况

2004年4、7、8、11、12月采用微型捕集管-冷原子荧光光谱法对贵阳市一个居民区大气中的痕量颗粒态总汞(TPM)进行了测定。结果表明:TPM日均浓度范围是0.149~4.853 ng.m-3,平均值是1.091 ng.m-3,显著高于背景参考值1~86 pg.m-3;TPM浓度采暖期大于非采暖期,夜间通常大于白昼;TPM与大气气态总汞(TGM)可能具有同源性;燃煤、垃圾焚烧以及周边工厂排放的含尘烟气可能是居民区大气颗粒态汞的主要人为来源。     

贵阳市区大气降水中有机酸的研究

利用ICS-90常规离子色谱结合RFC-30型淋洗液在线发生器,对贵阳市区大气降水中的小分子有机酸进行了系统研究。测得贵阳市降水中的有机酸主要以甲酸[质量分数为(0.2-4.5)×10-6]、乙酸[质量分数为(0.6-5.3)×10-6]、草酸[质量分数为(0.1-4.9)×10-6]为主,其次是乳酸和丙酮酸,及少量丙酸和甲烷磺酸;有机酸对降水自由酸平均贡献为23.2%,占总阴离子的1.4%;通过比较贵阳市区有机酸前后二十年的变化,得出现阶段可能至少有近1/2乙酸和3/4甲酸来源于人类的活动,这说明有机酸人为源是其来源的重要组成部分。     

淮南深部山西组煤中汞的含量分布及赋存特征研究

以淮南煤田深部山西组煤为研究对象,分别采集研究区张集煤矿和新集二矿二叠系山西组1煤层的煤样品,测试了样品中总汞的含量,分析汞的空间分布特征,采用浮沉实验、逐级化学提取实验以及相关性分析研究了煤中汞的赋存状态,并结合沉积环境探讨了深部山西组煤中汞的富集成因.结果 表明:(1)研究区煤样中汞含量介于0.03～0.93 μg...