Hygroscopic properties of sodium and potassium salts as related to saline mineral dusts and sea salt aerosols

Mineral dust, soil, and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere, and their hygroscopicity affects the hydrological cycle and global climate. We investigated the hygroscopic behaviors of six Na- and K-containing salts commonly found in those primary organic aerosols. Their hygroscopic growths as a function of relative humidity (RH) agree well with thermodynamic model prediction. Temperature dependence of deliquescence RH (DRH) values for five of those salts was also investigated, which are comparable to those in literature within 1%–2% RH, most showing negative dependence on temperature. Hygroscopic growth curves of real-world soil and sea salt samples were also measured. The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition. The substantial amounts of water-soluble ions, including Na⁺ and K⁺, in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH (>80%) conditions. For three less-hygroscopic dust samples, however, measurements showed higher water uptake ability than that predicted by the thermodynamic model. The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH. The results of this study provide a comprehensive characterization of the hygroscopicity of Na- and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.     

高效除砷分子筛新型材料制备及其吸附特性研究

为提高4A分子筛(MS)对水溶液中砷的吸附性能,以MS为载体,采用浸渍法制备载铁分子筛(FMS)和铁锰分子筛(FMMS)作为除砷吸附剂,利用扫描电镜(SEM)、傅里叶红外光谱(FT-IR)、比表面积测试法(BET)等手段对MS和FMS微观结构特点进行表征,并开展批次试验考察FMS和FMMS对水中五价砷(As5+)和三价砷(As3+)的吸附效果,对FMS吸附As5+过程进行吸附动力学、等温吸附试验和吸附热力学等拟合.结果表明:①铁盐浸渍改性能有效提高MS比表面积、改善其表面结构,改性后FMS是一种窄孔径、尺寸均匀的介孔材料,比表面积和孔体积分别从27.38 m2/g和0.068 cm3/g增至281.25 m2/g和0.16 cm3/g,平均孔径由9.93 nm减至2.21 nm;MS微观结构由密实粗糙颗粒转变为疏松多孔隙结构.②FT-IR表明,铁盐浸渍形成的铁氧化物主要与MS结构中O—H、Al—O和Si—O结合;批次试验设定ρ(As5+)为4 mg/L,与MS相比FMS对As5+的去除率约提高70%.③吸附动力学结果显示,FMS对As5+的吸附过程符合准二级动力学模型,相关系数(R2)达0.99,反应过程中化学吸附起主要作用.④等温吸附试验表明,FMS对As5+吸附过程与Freundlich等温吸附模型拟合程度较高,相关系数(R2)达0.98,计算最大吸附容量为9.9 mg/g.⑤热力学参数ΔG、ΔH和ΔS计算表明,温度升高有利于FMS吸附砷,反应过程中FMS表面固体与溶液的混乱度上升.⑥与FMS相比,FMMS对As3+吸附性能有效提高,ρ(As3+/As5+)(As3+与As5+共存条件下溶液质量浓度)分别为2.0、4.0、6.0 mg/L下,FMMS去除率分别约提高26.34%、28.06%和28.09%.研究显示,利用铁盐浸渍法对MS改性可有效提升其对As5+和As3+的吸附容量,发挥材料的实际运用价值.      

模拟南海大气环境下耐候钢腐蚀性能研究

目的通过室内模拟南海大气环境加速腐蚀试验,对比分析几种钢腐蚀性能优劣,为开发耐南海大气腐蚀用钢提供数据支撑和理论依据。方法分别选用Q235B,Q355和Q500q E三种材料作为研究对象,采用中性盐雾试验方法模拟南海苛刻大气环境对试样进行耐蚀性测试,通过试样表面形貌观察、腐蚀质量损失计算和电化学分析等手段研究其腐蚀行为机制。结果 Q235B表面最先被腐蚀产物完全覆盖,腐蚀速率始终大于另外两种材料。Q355和Q500q E表面膜初期起到延缓腐蚀作用,其中以Q500q E极化阻抗最大,腐蚀表面最为平整。结论模拟南海大气环境下三种试验钢耐蚀性能排序为Q500q EQ355Q235B。     

7A52铝合金等离子弧焊接头盐雾腐蚀行为研究

目的研究7A52装甲铝合金等离子弧焊接接头耐海洋大气环境的腐蚀特征和规律。方法通过盐雾加速腐蚀试验进行腐蚀评估,并在腐蚀后利用扫描电子显微镜(SEM)观察腐蚀产物微观形貌,并分析腐蚀时间对腐蚀性能的影响,通过能谱(EDS)分析腐蚀产物的元素组成。结果 7A52铝合金焊接接头盐雾腐蚀初期(8 h)热影响区首先出现点蚀,随着腐蚀时间延长(12 h),母材和焊缝发生点蚀,热影响区腐蚀产物层氧的含量最多。结论 7A52装甲铝合金等离子弧焊接接头处热影响区是腐蚀敏感区,热影响区比焊缝区和母材区耐蚀性稍差。     

Effects of ultraviolet radiation on toad early life stages

Background  Exposure to harmful levels of ultraviolet-B radiation (UVB), a component of solar radiation, has been suggested as a potential cause of amphibian declines. Methods  We measured solar radiation (UVB, ultraviolet-A, and visible) wavebands in breeding ponds of Bufo boreas (boreal toad, a montane species that has undergone severe population declines) and Bufo woodhousii (Woodhouse’s toad, a plains toad that has not experienced declines) and examined tolerances of these species to simulated solar UVB exposures in the laboratory. Results  We found larvae of both species to be tolerant of simulated solar UVB in excess of solar UVB levels observed in their breeding ponds. B. boreas tadpoles were more tolerant of simulated solar UVB exposure than B. woodhousii tadpoles, possibly because of greater amounts of photoprotective melanin in B. boreas skin. Conclusions  UVB levels observed in B. boreas habitats do not currently appear to constitute a threat to the survival of these animals; however, long-term (>1 month) exposure to UVB levels comparable to levels associated with the water interface appears to reduce survival in B. woodhousii tadpoles. Therefore, future increases in surface and water column UVB radiation in bufonid habitats might pose significant survival risks to B. boreas or B. woodhousii populations.     

复合电化学法处理含盐有机废水

研究了复合电化学法处理含盐，酚废水的可行性及处理效果，实验结果表明，在110－160℃，PH3-3.5，处理电压5V，电流密度6-9mA/cm^2,H2O2/苯酚（质量比）＞0．06时，200mg/L的苯酚溶液经处理后，酚去除率大于98％，CODCr去除率大于70％，该法电能消耗低，是一种适合于含盐有机废水处理的新方法。     

膜蒸馏-结晶技术的研究现状和发展前景

膜蒸馏-结晶工艺是一种新的回收纯物质方法，尤其从废水中分离出晶体。对于膜蒸馏-结晶技术进行了综述，介绍了膜蒸馏-结晶技术的优点，以及工艺控制的关键技术。概述了膜蒸馏-结晶的起源和国内外研究现状，指出了膜蒸馏-结晶在高浓度无机盐废水中应用的优势，预测其在该方向上很好的发展前景。     

EFFECTS OF URBAN LAKES ON QUANTITY AND QUALITY OF BASEFLOW1

ABSTRACT: Man-made lakes have significant impacts on the hydrologic conditions in the watershed in which they are built. This paper examines the nature of the impact upon baseflow by comparing baseflow conditions at the outlet of the lakes with those elsewhere in the watershed. Situated in the upper reaches of a small watershed, the lakes studied have only a minor effect upon the magnitude of baseflow discharge, increasing it slightly from October to January, and decreasing it from May to September. Baseflow quality is substantially affected. Natural dissolved ions, as represented by magnesium, are generally decreased in concentration and total load by the lakes. Road salt related inons are substantially increased in both concentration and total load in the baseflow. Surface runoff stored in the lakes is extremely enriched in salt in the winter, and the storage capacity of the lakes is sufficient to maintain winter salt concentrations in the baseflow near the lakes until summer. The storage effect also tends to damp out seasonal fluctuations in baseflow chloride content which are extreme in suburban watersheds. The difference in quality between the lake and non-lake baseflows and the linear distance needed for complete mixing are used as measures of the magnitude and distal extent of the lake effect on baseflow quality.     

分段重铬酸钾法测定高氯离子废水COD方法研究

通过对高盐废水COD测定时氯离子干扰与氧化剂浓度的关系研究发现:氧化剂浓度对氯离子干扰程度有较大的影响。根据研究结果,提出了用分段重铬酸钾法测定高盐废水COD的设想,并对此设想进行了验证。验证结果表明:用分段重铬酸钾法测定高盐废水COD的设想是完全可行的;而且方法的准确度较好,相对误差<9%,实际废水加有机物的回收率>92%。     

华北城市地区潜水中主要离子含量变化的反应途径模拟

近三十年来，由于污染，华北城市地区潜水中主要离子如Ｃａ￣（２＋）、Ｍｇ￣（２＋）等含量逐年升高，影响工农业生产，本文采用反应途径模拟的方法对上述情况进行了研究，作者共设计了７种反应途径，分别模拟了含碳酸盐或硅酸盐、铝硅酸盐较丰富地区地下水中盐效应和ＣＯ＿２分压升高对其主要离子含量的影响．模拟过程中考虑了２２种化学反应，３３种存在形式（包括气体、固体）。结果表明，盐效应和ＣＯ＿２分压升高对地下水中Ｃａ￣（２＋）、Ｍｇ￣（２＋）浓度的升高有明显影响，上述两种因素对Ｃａ、Ｍｇ硅酸盐、铝硅酸盐溶解的影响更为明显。