夏季玉龙雪山地区不同水体常规阴离子特征及其来源分析

依据Dionex-3000型离子色谱仪和Dionex-600型离子色谱仪测定的云南省丽江市玉龙雪山地区2005年7月22日～7月28日不同水体的阴离子数据及同期降水中的无机离子数据,运用系统聚类、海盐示踪、后推气流模型分析等方法,分析了人类活动、岩石岩性、大气干湿沉降对我国云南省丽江市玉龙雪山地区不同水体阴离子构成和浓...     

Effectiveness of vegetation on phosphorus removal from reclaimed water by a subsurface flow wetland in a coastal area

This work was conducted to evaluate the effectiveness and influence factors of vegetation on phosphorus (P) removal from reclaimed water in constructed wetlands. Comparisons were conducted between one pilot scale subsurface flow wetland (P-SSFW) and two demonstration subsurface flow wetlands, which were series-wound and named as first subsurface flow wetland (F-SSFW), and second subsurface flow wetland (S-SSFW), respectively. The three wetlands had the same vegetation and substrate, but different pH values, total dissolved solids (TDS) and P loads. Results showed that the P content in the vegetation shoots of the F-SSFW was 2.16 mg/g, while 2.31 mg/g in the S-SSFW and 2.69 mg/g in the P-SSFW. These differences were likely caused by the higher pH and TDS in the reclaimed water. The P content also differed among the tissues of the plant, which were 5.94-6.44 mg/g, 2.20-2.77 mg/g, 1.31-1.46 mg/g and 1.53-1.88 mg/g in the flowers, leaves, stems, and roots, respectively. The greatest discrepancy was observed in the leaves, indicating that the environment of the wetlands had the greatest influence on the leaves. When the total phosphorus (TP) load was lower, the proportion of P removed by vegetation assimilation was 16.17% in the P-SSFW, 12.90% in the F-SSFW and 13.29% in the S-SSFW. However, the relative removal efficiency by vegetation among the three wetlands did not vary greatly from that observed in other studies. Moreover, the influence of pH, TDS and TP load was not as great as the influence of the vegetation species, type of substrate, influent style or climate.     

典型区域地下水硝酸盐污染及来源分析

地下水的硝酸盐污染日趋严重.本文通过对典型区域地下水取样调查以及水化学和氮同位素分析,确定了研究区域地下水硝酸盐污染程度并对污染源进行了分析,结果表明:研究区地下水中的无机氮化合物主要以NO3-形式存在,浅层地下水中NO3- -N含量变化范围在2.94～28 mg/L之间,有4个水样的NO3- -N含量超过了我国《地下...     

Impact of energy structure adjustment on air quality: a case study in Beijing, China

Energy consumption is a major cause of air pollution in Beijing, and the adjustment of the energy structure is of strategic importance to the reduction of carbon intensity and the improvement of air quality. In this paper, we explored the future trend of energy structure adjustment in Beijing till 2020, designed five energy scenarios focusing on the fuel substitution in power plants and heating sectors, established emission inventories, and utilized the Mesoscale Modeling System Generation 5 (MM5) and the Models-3/Community Multiscale Air Quality Model (CMAQ) to evaluate the impact of these measures on air quality. By implementing this systematic energy structure adjustment, the emissions of PM₁₀, PM_2.5, SO₂, NO _x , and non-methane volatile organic compounds (NMVOCs) will decrease distinctly by 34.0%, 53.2%, 78.3%, 47.0%, and 30.6% respectively in the most coalintensive scenario of 2020 compared with 2005. Correspondingly, MM5-Models-3/CMAQ simulations indicate significant reduction in the concentrations of major pollutants, implying that energy structure adjustment can play an important role in improving Beijing’s air quality. By fuel substitution for power plants and heating boilers, PM₁₀, PM_2.5, SO₂, NO _x , and NMVOCs will be reduced further, but slightly by 1.7%, 4.5%, 11.4%, 13.5%, and 8.8% respectively in the least coal-intensive scenario. The air quality impacts of different scenarios in 2020 resemble each other, indicating that the potential of air quality improvement due to structure adjustment in power plants and heating sectors is limited. However, the CO₂ emission is 10.0% lower in the least coal-intensive scenario than in the most coal-intensive one, contributing to Beijing’s ambition to build a low carbon city. Except for energy structure adjustment, it is necessary to take further measures to ensure the attainment of air quality standards.     

硫自养反硝化饮用水脱氮：悬浮填料与硫源作用效果评估

针对饮用水硝酸盐污染和固定床硫自养反硝化脱氮负荷低等问题,开展流化床型硫自养反硝化脱氮研究,探究聚乙烯醇-海藻酸钠-活性炭悬浮填料对硫自养反硝化的影响,并对比了不同硫源(升华硫、硫代硫酸钠和生物硫)对反硝化效果的影响.结果表明,悬浮填料可显著提升反硝化脱氮效果,升华硫与硫代硫酸钠效果优于生物硫.在最佳条件下,TN去除率可稳定保持在98.49%,TN脱氮负荷达2.84 g·L^-1·d^-1.机理分析表明,悬浮填料中海藻酸钠可作为异养反硝化的有机碳源,实现自养与异养反硝化相结合,减少了副产物NO₂^-和SO₄^2-的生成,并提供碱度,保持体系pH的稳定.加入悬浮填料后,反硝化微生物生长得到促进,优势菌属为Thauera(兼性自养反硝化菌)和Brachymonas(异养反硝化菌).     

煤矿天然制冰降温技术的可行性分析

借鉴国内外天然制冰的相关资料,提出了用于矿井降温制冷的天然制冰降温技术.通过建立冰池喷淋制冰和蓄冰模型,从理论上分析了天然制冰技术的可行性.通过对制冰费用与矿井当前降温费用的比较,突出了该技术研究的经济效益.同时,对该技术存在的相关问题进行了分析,对研究前景进行了展望.     

红外法测定皮革行业油类物质过程中几个关键技术问题的探讨

红外分光光度法测定皮革行业油类物质时,样品的采集、测试条件的选择、萃取剂的用量、萃取的次数等等对测定结果的准确性有很大的影响,在实际工作中应把握几个关键技术环节,以保证监测结果的准确可靠。     

小麦赤霉病气象环境成因研究进展

综述了国内外有关小麦赤霉病发生流行的气象环境成因方面的研究成果及其最新进展,包括小麦赤霉病发生流行的单一、多个气象因子和大尺度气候因子及其对小麦赤霉病发生流行的可能影响。结果表明:温度、雨湿条件、光照、风等气象要素在一定程度上决定了小麦赤霉病的发生流行程度;当温、湿等气象要素,菌源数量与花期在一定程度吻合时,会导致该病的大流行;El Nino和SST异常对赤霉病的发生流行有前兆性指示作用;结合地面气象因子、海温和500HPa高空环流建立的预测模型能够较好地预测赤霉病。还指出了目前研究中存在的不足,对该领域未来研究的发展方向进行了展望。     

基于氯化BiOBr/TiO2的新式臭氧转化反应

利用溶胶凝胶法制备了BiOBr/TiO₂复合型光催化剂并进行氯化改性,紫外照射下表现出了较高的臭氧转化能力.随后利用XRD、UV-Vis DRS、TEM、EPR、电化学等方法对催化材料进行表征,分析其光催化反应原理.结果表明,BiOBr/TiO₂对臭氧的转化率提升至61%,这是由于二者形成了半导体异质结,光生电子传递降低了载流子复合率,羟基自由基生成量增加;氯化材料的转化率进一步大幅提升至99%,这是由于氯元素在光照条件下生成氯自由基,进而驱动了一种效率更高的链式传递反应.该反应体系在较高湿度下未见明显失活,优于传统α-MnO₂,具有应用潜力.     

Colonization of Penicillium oxalicum SL2 in Pb-contaminated paddy soil and its immobilization effect on soil Pb

Penicillium oxalicum SL2 (SL2) is a previously screened Pb-tolerant fungus that can promote crops growth. The relationship between SL2 colonization and Pb immobilization was studied to provide a theoretical basis for microbial remediation of Pb-contaminated paddy soil. In this study, green fluorescent protein (GFP) labeled SL2 was inoculated into different Pb-contaminated paddy soils (S1-S6). The Pb extracted from the soil by HNO₃, EDTA and CaCl₂ were used to characterize the available Pb. The results showed that the colonization of SL2 was divided into lag phase (0-7 days), growth phase (7-30 days), and mortality phase (30-90 days). SL2 colonized well in sandy soils rich in clay and total phosphorus with initial pH of 4.5-7.0. In addition, SL2 increased soil pH and decreased soil Eh, which was beneficial to immobilize Pb. In different soils, the highest percentages of CaCl₂-Pb, EDTA-Pb, and HNO₃-Pb immobilized by SL2 were 34.34%-40.53%, 17.05%-20.11%, and 7.39%-15.62%, respectively. Pearson correlation analysis showed that the percentages of CaCl₂-Pb and EDTA-Pb immobilized by SL2 were significantly positively correlated with the number of SL2 during the growth phase. SL2 mainly immobilized Pb in the growth phase and a higher peak number of SL2 was beneficial to the immobilization of Pb.