高氯废水中化学需氧量的测定

文章研究了一种适用于高氯废水的无汞测定化学需氧量的方法。水样中加入10 mL重铬酸钾和15 mL浓硫酸,消解0.5h,冷却至室温再加入0.3 g硫酸银,消解1.5 h,测得其COD测定值,根据COD Cl-Cl-的关系曲线得到由氯离子产生的COD Cl-,将COD测定值减去C OD Cl-即为水样的COD真实值。实验证明,该方法适用于氯离子浓度不超过5 000 mg/L废水COD的测定。     

桂西北峰丛洼地泉水和溪流在降雨过程中的水化学动态变化特征

通过对中国科学院环江喀斯特农业生态系统观测研究站所在区域的泉水和溪流在降雨时的连续采集,发现二者的水化学特征对降雨的响应较快,但变化却不同。降雨时泉水的pH值在降雨时降低,电导率和主要离子浓度升高,SI降低,pCO2升高,而溪流的电导率和主要离子浓度降低,碳酸盐矿物饱和指数(SI)降低,水中二氧化碳分压(pCO2)降低。降雨时泉水和溪流的溶质输移速率明显增加,但没有表现出在连续降雨中因为降雨强度大输移速率就高的现象,从而推断,除了雨水的稀释作用和"土壤CO2效应"外,土壤包气带的"前水"以及土壤中可交换态离子也影响了降雨时峰丛洼地水体中溶质的运移。     

持久性有机污染物的水污染控制:吸附富集、生物降解与过程分析

介绍了持久性有机污染物(POPs)的定义、来源以及我国涉及POPs的工业生产与数量分布,明确氯碱工业、有机氯工业等精细化工业与垃圾焚烧厂产生的POPs成为未来的主要污染源;对统计数据进行分析指出,由于历史上POPs的应用以及排放,我国工业发达地区河段水体中普遍检出POPs,浓度为几到几十ng·L-1范围,部分流域超标;...     

新化工装置风险评价方法的研究

回顾了中国与欧美化工新装置风险评价技术的发展,分析了中国与欧美风险评价的异同、中国风险评价存在的问题。结合作者的实践,介绍与讨论了新化工装置设立安全评价阶段的风险评价方法,推荐和介绍了物理化学方法作为评价方法应用的实例。专家分析评议法、物理化学方法、评价软件模拟等评价方法的综合使用,尽可能地做到根据经验、专业知识从已建装置分析拟建装置、利用物化方法较系统地分析装置反应过程、利用评价软件直观地模拟风险,各种评价方法互补、定性与定量互补,从而较系统、完整地完成化工新装置的安全评价工作,以减少装置的安全隐患,有助于使装置顺利地投入运行。     

基于SPEI的西南地区近53 a干旱时空特征分析

论文基于标准化降水蒸散指数（SPEI）,统计分析西南地区128 个测站1960-2012 年的气象数据,从干旱年际变化趋势、四季变化趋势、干旱强度、干旱事件频次、干旱频率以及与ENSO的关系,对西南地区近半个世纪的干旱时空特征进行了分析。结果表明：①西南地区及子区域近53 a 来呈干旱化趋势,21 世纪初干旱发生最频繁,干旱强度、极端干旱及中等干旱的频次均呈增加趋势;②四季大部分区域呈干旱化趋势,以秋季最为突出;③春季,干旱发生频率最高且集中在横断山地、四川盆地东部和云贵高原中部,夏季,横断山地北部、若尔盖高原和广西丘陵西北部易发生干旱,秋季,云贵高原、广西丘陵及四川盆地部分区域干旱频率较高,冬季,干旱易发区集中在若尔盖高原、四川盆地西南部一线;④各区域四季的干旱指数与ENSO指数相关性不同,并且ENSO事件强度与四川盆地和横断山地的SPEI 在年变化趋势方面存在明显负相关,与其他区域呈正相关。此外,西南地区在厄尔尼诺年和拉尼娜年都会出现干旱,但前者爆发干旱灾害的概率比后者高。而且各区域存在差异,四川盆地、若尔盖高原在厄尔尼诺年易发生干旱,而云贵高原在拉尼娜年发生频率较高,广西丘陵、横断山地没有明显规律和特征。     

某化工企业内操职业心理现状分析与改进

通过对某化工企业室内操作人员(以下简称内操)职业心理现状进行的调查分析,追踪内操职业心理成因并提出建议与指导,通过一系列措施的制定和落实,改进管理,改善内操心境,引导内操健康生活、快乐工作。     

2001~2019年气象条件对江苏省PM2.5分布的影响

利用区域在线空气质量模式WRF-Chem模拟研究了2001～2019年气象条件对江苏省PM_2.5浓度分布的影响.在排放源不变的情况下,气象条件引起的江苏省PM_2.5年均浓度的最强正、负异常分别出现在2008和2001年,它们的异常值相对于多年平均值分别占比10.5%和-14.3%,表明气象条件对PM_2.5浓度年际变化有明显影响.经验正交函数分解的结果表明,气象条件对江苏省PM_2.5浓度的空间分布的影响具有一致性.边界层高度、温度、相对湿度、风速和降水整体上都与江苏省PM_2.5浓度呈现显著负相关关系.以上气象因子所构建的线性回归方程能较好地描述PM_2.5浓度和气象条件之间的关系,其拟合值与模拟值相关性为0.73,通过了99%的信度水平检验.     

Response of soil CO2 efflux to precipitation manipulation in a semiarid grassland

Soil CO_2efflux(SCE) is an important component of ecosystem CO_2 exchange and is largely temperature and moisture dependent, providing feedback between C cycling and the climate system. We used a precipitation manipulation experiment to examine the effects of precipitation treatment on SCE and its dependences on soil temperature and moisture in a semiarid grassland. Precipitation manipulation included ambient precipitation, decreased precipitation(- 43%), or increased precipitation(+ 17%). The SCE was measured from July2013 to December 2014, and CO_2 emission during the experimental period was assessed.The response curves of SCE to soil temperature and moisture were analyzed to determine whether the dependence of SCE on soil temperature or moisture varied with precipitation manipulation. The SCE significantly varied seasonally but was not affected by precipitation treatments regardless of season. Increasing precipitation resulted in an upward shift of SCE–temperature response curves and rightward shift of SCE–moisture response curves,while decreasing precipitation resulted in opposite shifts of such response curves. These shifts in the SCE response curves suggested that increasing precipitation strengthened the dependence of SCE on temperature or moisture, and decreasing precipitation weakened such dependences. Such shifts affected the predictions in soil CO_2 emissions for different precipitation treatments. When considering such shifts, decreasing or increasing precipitation resulted in 43 or 75% less change, respectively, in CO_2 emission compared with changes in emissions predicted without considering such shifts. Furthermore, the effects of shifts in SCE response curves on CO_2 emission prediction were greater during the growing than the non-growing season.     

超声波诱导催化氧化处理有机化学实验室废水的初步试验

采用超声波诱导催化氧化处理有机化学实验室废水,探讨了超声辐射时间等因素对有机化学实验室废水处理效果的影响,获得了最佳工艺条件：100mLCOD为4632mg／L的废水（初始pH值=3）在超声辐射反应时间50min,Fe^2＋离子浓度为100mg/L,H2O2浓度为800mg／L的条件下,COD去除率达到79％。     

Four storms with sub-events: sampling and analysis

Analysis of ion concentration of samples taken sequentially during a storm event is important in order to reveal the relation between the atmospheric conditions and ion concentrations in each sub-event. This study presents the interrelationship among the chemical composition parameters and atmospheric variables for four storm events that were sampled in Istanbul during a) January 21-23, 2004 b) November 9-11, 2003 c) February 12-13, 2004 and d) October 27-28, 2003. These events lasted 53.3, 47.9, 27.5 and 13.2 h and the number of collected samples for each event was 22, 14, 7 and 4, in order. Generally values of pH and concentrations of ions in the first sub-events for all four cases were found higher than those of the other sub-event samples taken in sequence owing to the strong initial washout of the atmosphere by raindrops. Precipitation events a and c include rain and snow together where precipitation started as rain and continued as snow after 16th and 3rd sub-events. Higher concentration of ions in the snow in comparison with that of rain sub-events samples can be explained by more efficient below cloud scavenging of atmospheric constituents, especially aerosol particles, by snowflakes. In general, all of the ions sampled in the sub-events for four storms have variability similar to each other, with high correlation coefficient among themselves. Cl(-) and SO(4)(2-) were found to be the dominant ions in average overall sub-events. Calculated NSS concentration values of ions indicated that the main source of SO(4)(2-) was industrial and domestic emissions, most of the Ca(2+) and K(+) came from soil, nearly half of the Mg(2+) and all of the Cl(-) originated from sea.