Retention behavior of hydrophobic organic chemicals as a function of temperature in soil leaching column chromatography

To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in soil/solvent system, a soil leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20-40 degrees C was carried out, which utilized a reference soil (SP 14696) packed column and a methanol-water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 degrees C (k'30/k'40) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability-dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former.     

Implications of rhizospheric heavy metals and nutrients for the growth of alfalfa in sludge amended soil

Rhizospheric distribution of nutrients and heavy metals in sludge amended soil was investigated using the rhizobag technique to give an indication of the release of metals from wastewater sludge. DTPA-extractable Zn, Cd, Ni and Mn, and available P, K and NH4+-N in the rhizosphere were markedly depleted when soil was amended with sludge. There was no conspicuous depletion or accumulation of DTPA-extractable Cu in the rhizosphere when the soil was amended with sewage sludge but DTPA-extractable Fe accumulated in the rhizosphere when the soil was amended with increasing amounts of sludge. The pH value in the rhizosphere increased with distance from the roots when soil was amended with larger amounts of sludge. The exchangeable fraction of Cu in the rhizosphere was depleted whether or not the soil was treated with sludge. Carbonate, oxide, organic and residual fractions of Cu and Zn were depleted in the rhizosphere at a distance of 0-2 mm from the roots when soil was amended with 50% sludge. Application of sewage sludge had a positive effect on alfalfa growth. With an increase in sludge amounts, the concentrations of Fe, Cu and Zn in alfalfa shoots did not change. Soil amendments with less than 25% sludge did not increase the availability or mobility of heavy metals. The depletion in rhizospheric DTPA-extractable Zn, Cd and Ni indicates that with the sole exception of Cu, release of metals from sludge amended soil was very limited.     

垃圾渗滤液烟气脱硫体系的实验研究

利用垃圾渗滤液中较高的碱度吸收二氧化硫是垃圾渗滤液湿法烟气脱硫工艺的第一阶段。试验证明 ,垃圾渗滤液可高效吸收二氧化硫 (去除率可达 90 %以上 ) ;同时垃圾渗滤液中氨氮浓度由 133mmol L降至 78mmol L。实验结果证实了所建立的垃圾渗滤液烟气脱硫体系的互补性     

Role of cupric ions in the H2O2/UV oxidation of humic acids

The purpose of this study is to reveal the role of cupric ions as a natural water contaminant in the H2O2/UV oxidation of humic acids. Humic acids are naturally occurring organic matter and exhibit a strong tendency of complexation with some transition metal ions. Chlorination of humic acids causes potential health hazards due to formation of trihalomethane (THM). The removal of THM precursors has become an issue of public concern. The H2O2/UV process is capable of mineralizing humic acids due to formation of a strong oxidant, hydroxyl radicals, in reaction solution. Experiments were conducted in a re-circulated photoreactor. Different cupric concentrations (0-3.8 mg/l) and different pH values (4-9) were controlled to determine their effects on the degradation of humic acids, UV light absorbance at 254 nm, and H2O2. The presence of cupric ions inhibits humic mineralization and decreases the rate of destruction of humic acids which absorb UV light at 254 nm. On the other hand, the higher the cupric concentration, the lower the H2O2 decomposition rate. In the studied pH range, the minimum of total organic carbon (TOC) removal occurs at pH = 6 in the presence of 2.6 mg/l of cupric ions; both acidification (pH = 4) and alkaline condition (pH = 9) lead to a better removal of TOC. It is inferred from this study that the cupric-complexed form of humic acids is more refractory than the non-complexed one.     

The resistance of Crassostrea rhizophorae to starvation and asphyxia

Experiments were performed on the oyster Crassostrea rhizophorae in order to determine the degree of its resistance to conditions of starvation and asphyxia imposed by longlasting transportation. The most favorable results were obtained by lowering the environmental temperature to about 15°C, and keeping the oysters in air, with a daily bath in hypercalcic seawater (Ca content double that of seawater). In this way mortality decreases and energetic reserves are not impaired. Oysters kept in water at their normal environmental temperature, without nutrition, reveal a noticeable increase in mortality and a decrease of about 40% in the glycogen and lipid reserves, during a 15 day starvation period. The normal values of some metabolic and compositional indexes in this species are: oxygen consumption 104±6 cm³ O₂/kg living body weight/h; water content 81±1%; protein content 7.4±0.4%; lipid content 1.6±0.1%; glycogen content 6.0±0.5%. The glycogen is distributed almost uniformly throughout all visceral organs. The oxygen consumption shows no circadial or tidal rhythmicity.With the technical assistance of the students A. Areces, A. Olaechea, M. Oliva, A. Otaso, M. Rodríguez.     

复合絮凝剂在治理棉纤维生产废水中的应用

运用正交实验设计的方法，对化纤厂生产棉浆粕过程中产生的黑液，进行了絮凝剂各类和用量的选择研究。据此，可以为确定工艺中絮凝剂的投加量提供初步数据。同时给出了化学耗氧量（COD）和总有机碳（TOC）之间的线性关系方程。     

Practical field application of a novel BOD monitoring system

A biochemical oxygen demand (BOD) monitoring system, based on electrochemically-active bacteria in combination with a microbial fuel cell, has been developed for the purpose of on-site, on-line and real-time monitoring of practical wastewater. A microbial fuel cell that had been enriched with electrochemically-active bacteria was used as the basis of the measurement system. When synthetic wastewater was fed to the system, the current generation pattern and its Coulombic yield were found to be dependent on the BOD5 of the synthetic wastewater. A linear correlation between the Coulombic yields and the BOD5 of the synthetic wastewater were established. Real wastewater obtained from a sewage treatment plant also produced a highly linear correlation between the Coulombic yield and BOD5 in the system. To examine on-site, on-line and real-time monitoring capability, the BOD monitoring system was installed at a sewage treatment plant. Over 60 days, the measurement system was successfully operated with high accuracy and good stability with the measuring period for a sample being 45 min. This application showed that the application of the measurement system was a rapid and practical way for the determination of BOD5 in water industries.     

环境监测数据法律地位的思考

概述了监测数据的法律地位，对指导当前的环境保护执法工作具有重要的现实意义．     

基于物联网的智能化安全仿真实训研究

结合物联网技术,介绍一种智能化安全仿真实训技术,通过对培训关键控制指标的筛选以及感知元件的应用,研发了安全仿真实训项目的感知层设计方案,以及多项目间的培训状态数据匹配技术,形成了系统的智能化安全仿真实训技术方案。通过与当前普遍应用的安全仿真实训技术进行对比,该技术方案能够有效提升培训考核的客观性,提高安全仿真实训实施效率,更好满足企业需求。     

基于生态型城市圈的西安大城市圈一体化交通运输体系发展研究

生态型城市圈应是按照生态学原理构建的,人居与自然和谐的新型城市圈发展模式。城市圈一体化交通运输体系通过综合方式解决城市圈交通运输问题,促进城市圈规划目标的实现。以生态型城市圈的内涵作为研究的出发点。对生态型城市圈的基本内容进行了分析,同时基于生态型城市圈的西安大城市圈发展目标,提出与之相契合的西安大城市圈一体化交通运输体系发展构架。。