氯化钡废液联产氢氧化钙和氯化钡

讨论了氯化钡废液联产氢氧化钙及高纯氯化钡的方法和主要影响因素。通过复盐共沉淀、热滤、结晶、精制纯化等工序,用氯化钡的蒸发残液制得了工业级的氢氧化钙和高纯度氯化钡,其纯度分别达95％和99．92％以上。采用有机溶剂析出法精制氯化钡,无需重结晶工序,是对传统工艺的一种改进。     

Influence of ionic strength and pH on the limitation of latex microsphere deposition sites on iron-oxide coated sand by humic acid

This study, for the first time, investigates and quantifies the influence of slight changes in solution pH and ionic strength (IS) on colloidal microsphere deposition site coverage by Suwannee River Humic Acid (SRHA) in a column matrix packed with saturated iron-oxide coated sand.Triple pulse experimental (TPE) results show adsorbed SRHA enhances microsphere mobility more at higher pH and lower IS and covers more sites than at higher IS and lower pH. Random sequential adsorption (RSA) modelling of experimental data suggests 1 μg of adsorbed SRHA occupied 9.28 ± 0.03 × 10⁹ sites at pH7.6 and IS of 1.6 mMol but covered 2.75 ± 0.2 × 10⁹ sites at pH6.3 and IS of 20 mMol. Experimental responses are suspected to arise from molecular conformation changes whereby SRHA extends more at higher pH and lower ionic strength but is more compact at lower pH and higher IS. Results suggest effects of pH and IS on regulating SRHA conformation were additive.     

土壤氮素及其环境效应

本文概述了土壤中含氮化合物的排放源、通量及其对环境的主要影响 ,并就这些氮素污染物与土壤理化因子和氮肥施用量之间的关系进行了简要的分析     

战略环境评价的几个基本问题

阐述了战略、环境效应与环境影响、战略环境评价等基本概念，分析了战略环境影响发生机理，提出战略环境评价的三种类型，即预测型ＳＥＡ、监控型ＳＥＡ和回顾型ＳＥＡ，并探讨了三类ＳＥＡ的区别和联系。     

安全政策评估分析与研究

分析了安全政策评估的内涵和主要内容及安全政策评估的必要性;对安全政策评估的类型进行了分类与阐述,着重对安全政策评估系统构成的5个要素,即评估者、评估对象、评估目的、评估标准和评估方法进行了分析和研究;最后,对安全政策评估的步骤和基本方法进行了初步的探讨。认为:提出及早开展安全政策评估工作,对指导新政策的制定、已实施政策的修订、把握政策执行方向以及控制安全生产形势均有重要作用。     

新型复合无机高分子混凝剂——聚硅氯化铝(PASC)的净水效果研究

采用共聚方法制备了系列具有不同碱化度（B）和Al/Si摩尔比的聚硅氯化铝（PASC），比较了它们与聚合氯化铝（PAC）的混凝效果及在处理后水中的残留铝含量，研究了B值和pH值对其残留铝含量的影响情况。探讨了PASC的混凝效果和残留铝含量与Al/Si摩尔比之间的关系。结果表明，PASC较PAC具有更好的混凝效果和较低的残留铝含量。对于高浊度水而言，具有适宜Al/Si摩尔比的PASC才具有良好的混凝效果，但对中、低浊度的地表水和含油废水而言，在实验的Al/Si摩尔比范围内，其值越小，混凝效果就越好。PASC在水体中的残留铝含量随着Al/Si摩尔比的降低和B值的升高而下降。PASC和PAC在中性pH条件下具有最低的残留铝含量。     

Ordering effects and choice set awareness in repeat-response stated preference studies

We present an experiment designed to investigate the presence and nature of ordering effects within repeat-response stated preference (SP) studies. Our experiment takes the form of a large sample, full-factorial, discrete choice SP exercise investigating preferences for tap water quality improvements. Our study simultaneously investigates a variety of different forms of position-dependent and precedent-dependent ordering effect in preferences for attributes and options and in response randomness. We also examine whether advanced disclosure of the choice tasks impacts on the probability of exhibiting ordering effects of those different types. We analyze our data both non-parametrically and parametrically and find robust evidence for ordering effects. We also find that the patterns of order effect in respondents' preferences are significantly changed but not eradicated by the advanced disclosure of choice tasks a finding that offers insights into the choice behaviors underpinning order effects.     

Photodegradation of the antibiotic spiramycin studied by high-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry

The degradation of spiramycin induced by ultraviolet (UV) irradiation was studied at pH 3–4, 6–7 and 8–9 using high-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry. Furthermore, the influence of hydrogen peroxide and oxygen on the photodegradation was investigated. Three degradation products were observed in the presence of oxygen and four in the absence of oxygen. The degradation kinetics were monitored as mass area-time curves, analyzed and described using subsequent follow-up reaction first-order models. The m/z values of the degradation products were determined to be 160, 322 and 366, the latter representing two separate products, the sugar moieties of spiramycin. Remainders of the macrocycle or the intact lactone ring of spiramycin were not observed, since the conjugated π-electron system was assumed photoexcited and thus undergoing photodegradation and fast destruction of the ring. The kinetic of the degradation of spiramycin itself was described using a first-order model. The degradation was accelerated upon addition of hydrogen peroxide. In contrast, systematic acceleration depending on pH could not be found. The absence of oxygen did not lead to any significant acceleration. The findings are interpreted in terms of the effectiveness of advanced oxidation processes and their potential use as a fourth purification step in wastewater treatment plants.     

两种评价森林资源生态环境效益计量方法的比较

对评价森林资源生态环境效益的 2种方法进行了比较 ,阐述了这 2种方法的优缺点 ,通过案例分析可知 :森林资源环境效果评价法获得的评价值大 ,而意愿调查法的评价值小 ,并说明了导致这 2种方法评价值不同的原因。     

丝瓜对食品废水的净化功能及经济效益

本文研究了丝瓜（Ｌｕｆｆａｃｙｌｉｎｄｒｉｃａ）在水面上的水培技术，对食品工业废水（啤酒废水）的净化功能及其经济效益。其试验结果表明：采用水培技术将丝瓜栽种在水面上是完全成功的。该法已经被应用到无锡市酿酒总厂食品工业废水净化处理。在５月份，丝瓜对啤酒废水中污染物ＴＮ的净化率为７８．６％，ＴＰ７８．０％，ＮＨ＋＿４－Ｎ９９．６％，ＣＯＤ２２．５％，浊度８０．９％。在６月份，丝瓜的净化率为ＴＮ８９．１％，ＴＰ９０．４％，ＮＨ＋＿４－Ｎ９９．２％，ＣＯＤ４４．１％和浊度８６．４％。由此可见，丝瓜是一种对食品废水净化的优良植物，其经济效益也很显著，每亩水面丝瓜（果实）可达２０００ｋｇ～２５００ｋｇ，经济价值达２０００元～２５００元。