Contamination status of dioxins in sediment cores from the Three Gorges Dam area, China

In order to screen dioxin pollution in sediment of Three Gorges Dam (TGD) area, three sediment cores were obtained from two sites in 2010~2011; each core was divided into different samples with every 10 cm depth. Sediment dating determined by radiometry (¹³⁷Cs, ²¹⁰Pb) and concentrations of dioxins were analyzed by high-resolution gas chromatography/mass spectrometry. The results indicated: Sediment dating showed no significant difference among all the samples from the same core and the two locations (ANOVA, p?>?0.05). The total amount of polychlorinated dibenzo-p-dioxins (PCDD)/Fs in all sample ranged from 30.7 to 371 pg/g dry weight (d.w.), with the mean value of 66.2 pg/g d.w. PCDDs occupied 60.33~85.22 % of dioxins in each sample, and PCDFs contributed to a very small extend. There was no significant difference in the dioxin concentration between 2010 and 2011 and in the two locations (t test, p?>?0.05), but the vertical distribution of dioxins showed significant different in different depths. Toxic equivalent (TEQ) (WHO 2005, Humans) of samples ranged from 0.15 to 1.60 pg/g d.w.; the mean was 0.41 pg/g d.w. No significant difference was found in TEQ between 2010 and 2011(t test, p?>?0.05). It could be concluded that the distribution of dioxins showed the spatial heterogeneous which resulted from the strong mixing and sediment deposition characteristics. Dioxin concentration in sediment cores was low with very low environmental risk potential. Dioxins at the two sites had the same origin, and exogenous input was the main source. It is the first report on the dioxins concentrations in sediment cores in the TGD area.     

低压稳流过滤器的研制及在油田污水处理中的应用

为了解决大庆油田现有核桃壳、石英砂过滤器反冲洗憋压、跑料和滤料再生困难等问题,在对原有过滤装置分析的基础上,根据反冲洗特性,对过滤器进行了改造,开发出低压稳流核桃壳过滤器和低压稳流石英砂过滤器。经现场测试,核桃壳过滤器反冲洗压力由原来的0.15～0.5 MPa降低到0.03～0.08 MPa,石英砂过滤器反冲洗压力由原来的0.27～0.46 MPa降低到0.17～0.20 MPa,且均能实现罐群水反冲洗。改造后核桃壳过滤器出水油平均含量13.4 mg/L,平均去除率为78.1%;出水悬浮物平均含量20.5 mg/L,平均去除率为55%。改造后石英砂过滤器出水油平均含量5 mg/L以下,平均去除率达到75%以上;出水悬浮物平均含量为9.8 mg/L,去除率达到80%以上。为了进一步提高过滤效果,在二级滤前投加絮凝剂形成微絮凝过滤工艺,出水悬浮物可达到3 mg/L,通过两级过滤达到特低渗透地层回注水标准。     

冠醚-离子液体体系对水相中铀酰离子的萃取

以二环己基-18-冠醚-6（DCH18C6）为萃取剂,一系列离子液体为溶剂的冠醚-离子液体萃取体系对水相中铀酰离子（UO22+）进行萃取实验。结果表明：UO22+在1-丁基-3-甲基咪唑双三氟磺酰亚胺盐（NTf2）体系的去除效率明显高于六氟磷酸盐类（PF6-）离子液体。在水相中当硝酸浓度在3 mol·L-1左右时萃取效率最高,体系的萃取效率随着萃取剂浓度的增加而变大,共存离子的加入会降低体系的萃取效率,但是当加入的是硝酸根离子时,萃取率会相应增大。根据实验结果分析可以判断此萃取体系主要为阳离子交换过程。     

碳纳米管电极原位产生过氧化氢及其对亚甲基蓝脱色效果简

将碳纳米管固定化制成多孔疏水性导电薄膜构建电化学阴极还原体系,实现过氧化氢在阴极的原位产生。电极特性研究表明,电极在较宽的电压范围内均具有较好的活性。考察了阴极电位、电极成分、氧气流量和电解质浓度对过氧化氢原位产生的影响,在优化条件下经过120 min后过氧化氢达到66.17 mg/L,并探讨过氧化氢原位产生的机理。在此基础上考察原位过氧化氢氧化工艺下对亚甲基蓝的脱色效果,并分析其脱色机理。     

GO/PAN复合正渗透膜制备的影响因素及性能分析

以聚丙烯腈(PAN)为制膜基材,采用界面聚合法制备复合正渗透膜,研究了不同基膜组成、界面聚合条件对复合膜性能的影响及抗污染性能,并进一步添加氧化石墨烯(GO)进行共混改性,优化复合正渗透膜性能。结果表明,最佳基膜组成为,以16%的PAN为聚合物,以N,N-二甲基甲酰胺(DMF)为溶剂。最佳界面聚合条件为,将基膜浸没在2%的间苯二胺(MPD)水相溶液(pH=9)中120 s,然后与0.1%的均苯三甲酰氯(TMC)进行界面聚合反应60 s从而生成活性层,且活性层正面附着,最后于60 ℃下热处理3 min,所得复合膜具有较好的渗透性能。此外,经GO改性后,复合膜表面形成一种具有不同含氧官能团的层层堆叠式GO片层,导致膜的水通量上升了26%,截留率依然保持在99.90%以上,并且复合膜的抗污染能力得到明显提高。     

Synergistic effects of liquid and gas phase discharges using pulsed high voltage for dyes degradation in the presence of oxygen

The technology of combined liquid and gas phase discharges (LGD) using pulsed high voltage for dyes degradation was developed in this study. Apparent synergistic effects for Acid orange II (AO) degradation in the presence of oxygen were observed. The enhancement of AO degradation rate was around 302%. Furthermore, higher energy efficiency was obtained comparing with individual liquid phase discharge (LD) or gas phase discharge process (GD). The AO degradation in the presence of oxygen by LGD proceeded through the direct ozone oxidation and the ozone decomposition induced by LD. Important operating parameters such as electrode distance, applied voltage, pulse repetition rate, and types of dyes were further investigated.     

铁改性海泡石除锑的影响因素研究

选择廉价海泡石, 用氯化铁对其改性。研究铁改性海泡石对锑的吸附特性。结果表明,氯化铁浓度、吸附时间、初始锑浓度以及温度等因素对锑的吸附影响较大,溶液初始pH影响不明显。在初始锑浓度50 mg/L,pH 6.8,5%氯化铁改性海泡石投加量为2 g/L,吸附90 min, 温度35℃下,吸附量可达21.6 mg/g。海泡石对吸附锑具有缓冲特性,溶液的初始pH值在3.1～10.1范围时,吸附后溶液的最终pH值为8～8.5。IMS吸附锑是放热过程。改性后海泡石比表面积增大,表面羟基数量增加,导致其吸附能力增强。通过XRD谱图并未发现铁晶体的存在。     

Study of water quality response to water transfer patterns in the receiving basin and surrogate model

Environmental Science and Pollution Research - The spatio-temporal response of water quality in the receiving basins to water transfer remains unclear when considering more practical factors....     

原位铁氧化物载铁活性炭的制备及其对水中As(Ⅲ)的去除性能

针对水中三价砷As(Ⅲ)毒害大、难去除的问题,本研究采用FeSO4/K2FeO4组合处理方式以恒温浸润法对活性炭进行改性,制备获得原位铁氧化物载铁活性炭(AFPAC),利用负载的铁氧化物的吸附性能,耦合活性炭的吸附和有效的固液分离功能,实现了As(Ⅲ)的高效去除.结果表明,当AFPAC投加量1g·L-1时,对初始质量浓...