北方典型岩溶泉域地下水水文地球化学特征分析——以鹤壁许家沟泉域为例

近年来,受采矿活动、气候变化等因素影响,包括鹤壁许家沟泉域在内的北方多数岩溶泉域水化学场发生了改变,但其演变规律及现状条件下的水文地球化学特征仍不明晰。为揭示现状条件下许家沟泉域地下水水文地球化学特征及其控制因素,本文在调查取样分析的基础上,采用数理统计、离子比例系数、Gibbs图及相关性分析等方法进行了研究。结果表明:泉域内岩溶地下水水化学类型主要为HCO_3-Ca·Mg和HCO_3·SO_4-Ca·Mg型。地下水主要水化学组分演化过程的主控因素是岩石风化作用,地下水中的Ca~(2+)、Mg~(2+)、SO_4~(2-)和HCO_3~-主要来源于含方解石(CaCO_3)、白云石(CaMg(CO_3)_2)的碳酸盐岩以及硫酸盐岩(CaSO_4·2H_2O)的溶解,一部分SO_4~(2-)来自黄铁矿氧化。脱白云石化作用致使泉域枯水期地下水中Mg~(2+)明显高于丰水期。阳离子吸附交替使地下水中Na~+、K~+含量降低。稳定同位素特征表明,泉域岩溶地下水主要接受西部裸露区大气降雨的入渗补给,泉域南部岩溶地下水还受淇河河水渗漏的影响,枯水期岩溶地下水中δ~(18)O存在漂移现象。研究成果为泉域内岩溶地下水的合理开发与保护提供了依据。     

Ex-ante environmental assessments of novel technologies - Improved caprolactam catalysis and hydrogen storage

Utrecht University has conducted a pilot sustainability assessment for the executive board of the chemistry program ACTS (Advanced Chemical Technologies for Sustainability) of the Netherlands’ Organization for Scientific Research (NWO). These assessments represent prospective, i.e. ’ex-ante’ studies on the production of caprolactam by an improved catalyst and on different hydrogen storage options (i.e. compressed and liquefied hydrogen, storage in metal hydrides and storage in a metal organic framework). The pilot sustainability assessments followed the principles of environmental life cycle assessment (LCA), thereby focusing on non-renewable energy use (NREU) and climate change (GWP100). It was found that caprolactam with the novel catalyst has lower impacts than petrochemical caprolactam production from benzene but higher impacts than bio-based caprolactam produced via fermentation. Regarding hydrogen storage, it was found that compressed and liquid hydrogen have the highest impacts. The impacts of the metal hydrides and the metal organic frameworks show by far the lowest environmental impacts. The main reason is that these materials can be reused up to 1500 times (refilling of tank), while for compressing and liquefaction of hydrogen energy is needed each time a tank needs to be refilled. The study demonstrates the successful application of ex-ante technology assessment.     

Survival in an extreme habitat: the roles of behaviour and energy limitation

Extreme habitats challenge animals with highly adverse conditions, like extreme temperatures or toxic substances. In this paper, we report of a fish (Poecilia mexicana) inhabiting a limestone cave in Mexico. Several springs inside the cave are rich in toxic H₂S. We demonstrate that a behavioural adaptation, aquatic surface respiration (ASR), allows for the survival of P. mexicana in this extreme, sulphidic habitat. Without the possibility to perform ASR, the survival rate of P. mexicana was low even at comparatively low H₂S concentrations. Furthermore, we show that food limitation affects the survival of P. mexicana pointing to energetically costly physiological adaptations to detoxify H₂S.     

双氧化剂光催化降解水中邻苯二甲酸酯类污染物

采用过硫酸钠/双氧水双氧化体系光催化氧化降解水中邻苯二甲酸酯类有机污染物,考察了过硫酸钠/双氧水的投加比例、紫外光强、溶液pH以及邻苯二甲酸二辛酯(DOP)的初始浓度等因素对降解率的影响,并在优化条件下对降解反应的动力学进行了考察。结果表明:室温下,过硫酸钠和双氧水浓度均为0.2mol/L且体积比为1:1,pH=7.0,光照距离为0.5cm,反应80min,DOP降解率达98%以上,反应动力学研究表明,过硫酸钠/双氧水双氧化体系光催化氧化降解水中DOP反应为表观一级。优于相同条件下两种氧化剂单独使用对DOP的降解效果。     

浸锌废水中氰化物和络合镍的处理研究与应用

电镀在表面前处理过程中产生一股浸锌废水,该浸锌废水中含有氰化物和高浓度的络合镍,采用常规的碱性氯化法难以使氰化物和镍达标;本文采用双氧水辅以硫酸铜为催化剂对某灯头电镀厂产生的浸锌废水进行处理研究。     

Total peroxides in rainwater at two mountainous sites and in Mexico City,Mexico

Rainwater samples were collected in the western sector of Mexico City (MC) and at Rancho Viejo (RV), 80 km west-south-west of MC, from 2001 to 2005, and Orizaba City (OC), about 90 km from the Gulf of Mexico, where rainwater collections were only possible on some weekends in 2001. Rainwater samples were treated in the field, and analysed by fluorescence at the laboratory. The volume-weighted mean concentration (VWMC) of H₂O₂ was 13.2 μM at RV, and 11.2 μM in MC, for the period 2001–2005. The highest VWMC was observed in OC (21.6 μM). The VWMCs for each year were 9.5, 14.4, 11.5, 16.7, and 14.3 μM at RV, and 12.2, 12.2, 14.3, 11.8, and 9.9 μM in MC, for 2001–2005, respectively. Hydrogen peroxide in rainwater correlated significantly and negatively with sulfate in both MC and RV, but not, however, in OC. This study confirmed that H₂O₂ concentration in rainwater is controlled by a complex combination of rain intensity, washout processes and in-cloud formation of H₂O₂, acting simultaneously. This was suggested by the fact that rain intensity seemed to predominate in certain rain fractions of a rain event, while washout processes seemed to predominate in other fractions of the same rain event.     

Hydrogen sulfide removal by iron containing activated carbon

Activated carbon modified by impregnation with iron (III) chloride solution (Fe‐ACs) were studied to try to raise their adsorption capacity for hydrogen sulfide, a malodorous substance.

The surface area and pore volume of activated carbon were decreased by impregnation, but the amount of hydrogen sulfide adsorbed onto Fe‐AC was larger than that onto raw activated carbon (R‐AC). In particular, a large increase of the amount adsorbed onto Fe‐AC was noted at low equilibrium pressure. It was assumed that the increase of amount of hydrogen sulfide adsorbed onto Fe‐AC was due to the chemical interaction between iron (III) chloride on the pores in addition to the physical adsorption onto pores of activated carbon. Fe‐AC shows a high selectivity for hydrogen sulfide.     

Investigation of hydrogen generation from municipal solid waste incineration fly ash

Hydrogen generation from municipal solid waste incineration fly ash was investigated to understand the influences of contacting method, kinds of contact solution, liquid to solid ratio, and particle size distribution of materials. Redox properties of materials and hydrogen generation were also studied. The largest quantity of gas generated in contact with water was 29.1 ml/g-ash, most of which was hydrogen. Fluidized bed fly ash generated more gas than stoker fly ash. In order to calculate the hydrogen generation potential (the maximum quantity of gas generated in contact with water), a novel system using a Y-shaped test tube and NaOH was utilized. This method gives values which are related to the quantity of generated gas in contact with water. A relationship between the aluminum content and hydrogen generation potential was observed, especially for fluidized bed fly ash. The reducing potential of fluidized bed fly ash was higher than that of stoker fly ash. Only fluidized bed fly ash showed a positive correlation between aluminum content and reducing potential, and between reducing potential and hydrogen generation potential. These results suggest that fluidized bed fly ash contains more Al⁰ than stoker fly ash. Received: September 11, 1998 / Accepted: March 19, 1999     

Prediction and minimization of vertical migration of DNAPLS using surfactant enhanced aquifer remediation at neutral buoyancy

Surfactant enhanced aquifer remediation (SEAR) had previously been thought to require a capillary barrier below the contaminated zone to prevent the vertical migration of a microemulsion containing solubilized DNAPL. This paper shows the vertical migration of the dense microemulsion is described and predicted by the value of three dimensionless scaling groups. Embedded within these scaling groups are four design parameters. The value of these parameters can be manipulated in order to reduce the amount of vertical migration anticipated for a given remediation design. Plots have been constructed that illustrate the relationship between vertical migration and the value of the scaling groups; such plots can be used to predict vertical migration and to determine appropriate screen intervals of extraction wells to ensure full capture of the contaminants. This predictive capability has been verified in laboratory experiments. Predicted migration of the microemulsion agreed within about 2% of that observed. Development of the scaling groups is presented, remediation design implications are discussed, and laboratory verification is shown. Additional discussion of the laboratory work is given in a companion paper [Kostarelos, K., Pope, G.A., Rouse, B.A., Shook, G.M., 1998. A new concept: the use of neutrally-buoyant microemulsions for DNAPL remediation, J. Contam. Hydro., this edition].     

催化极谱法测定降水中微量过氧化氢

在０．６ｍｏｌ／Ｌ磷酸介质中,钒５－Ｂｒ－ＰＡＤＡＰ与Ｈ２Ｏ２形成三元络合物,于０．０５Ｖ处产生一极灵敏的极谱波。过氧化氢浓度在０．０６－１７μｇ／２５ｍＬ范围内,峰电流与其含量呈良好线性关系。