城市再生水景观利用水华识别和预警方法探讨

城市再生水景观回用的主要问题是水体富营养化导致水华的暴发。为了抑制藻类的大规模生长,需要提前采取预防措施,以便将有可能爆发水华的藻类及时杀死或除去。目前,人们已经对景观水体中常见藻类的生长规律做了深入的研究,发现水体中藻数量(藻密度)的多少与水体的pH值和DO值的变化有密切而相对稳定的关系。通过在线实时监控pH值和DO值,找到△pH、△DO与藻类生长之间的关系,并结合pH、DO、温度、正磷酸盐和总氮等指标,实现实时识别和预测水华爆发的目的。     

基于高铁酸钾同步氧化-絮凝技术在污水处理中的研究进展

Fe(Ⅵ)具有较高的氧化还原电位,Fe(OH)3具有良好的絮凝效果,废水处理中高铁酸钾发挥同步氧化和絮凝作用。介绍高铁酸钾处理各种难降解废水的机理,同时分析高铁酸钾投加量、pH、反应温度、反应时间等因素对各种废水去除效果的影响。并提出基于高铁酸钾同步氧化絮凝技术处理污水的局限性和未来的发展方向。     

道路交通噪声不同预测模型之比较

目前,我国在进行道路交通噪声环境影响评价工作中主要使用的预测模型有2009声导则模型、2006规范模型,此外,也有部分噪声评价工作采用了德国的CadnaA软件。因各种模型在使用条件和参数选取等方面存在不同,导致预测结果存在差异。如何选取合适的预测模型,一直是国内学者不断研究想解决的问题。本文对已有道路交通噪声进行现场实测,通过设计不同的预测模式进行模型验证,将预测结果与实测值进行比较,结果表明这五种噪声预测模式中,模式一、模式四、CadnaA软件的噪声预测值与实际情况最相符,模式一绝对预测误差昼间在3.3-6.0 dB(A)之间,夜间在-3.4-0.2 dB(A)之间。使用2009声导则模型、2006规范模型相结合的预测模式更为准确。     

丽江盆地地表-地下水的水化学特征及其控制因素

2008年11月～2009年10月在丽江盆地-玉龙雪山地区采集白水河、三束河、哥吉河、束河河水及流域内地下水样品,使用离子色谱法分析了样品主要阴阳离子含量,研究了岩溶地区地表及地下水体的水化学特征、季节变化及其控制因素.结果表明,研究区水体均呈现弱碱性,主要离子组成以Ca2+和HCO3-为主,分别占阳离子和阴离子总量的54.8%和92.4%;不同季节河水的离子浓度差别较大,季风期离子浓度仅为西风期离子浓度的80%左右,表明季风期丰沛的大气降水输入对河水离子特征有较为显著的影响;河水离子浓度普遍低于盆地地下水主要阴阳离子浓度;河水和地下水的无机离子浓度都呈现出从高海拔到低海拔离子含量递增的规律.碳酸盐的风化溶解作用是水体离子的主要来源,季风期降水对水体的离子特征也有一定的影响,人类活动对人类聚居区部分天然水体已造成轻度污染.     

Ammonia volatilization and availability of Cu, Zn induced by applications of urea with and without coating in soils

Ammonia volatilization and the distribution of Cu and Zn were investigated in two types of soil treated with coated and uncoated urea. The rate of ammonia volatilization in two weeks after fertilizing with coated urea was 8% in soil 1 (soil derived from river alluvial deposits in Dongting Lake Plain) and 5.15% in soil 2 (red soil derived from quaternary red clay), about half the rates observed when fertilizing with common urea, implying that the hydrolysis speed of the coated urea was lower than for common urea, and that the coated urea can increase nitrogen use efficacy. As for the availability of Cu and Zn, their concentrations decreased in the first week after fertilization, and then increased, which was contrary to the effect of treatment on soil pH. For example, when the pH was 7.99, there was 0.79 mg/kg exchangeable Cu and 0.85 mg/kg exchangeable Zn in the soil derived from river alluvial deposits in Dongting Lake Plain. However, the concentrations of exchangeable Cu and Zn were generally lower for the common urea treatments than those with the coated urea because the peak pH for the common urea treatment was greater. The concentrations of these elements correlated well with pH in the range 4-8 in second order polynomial fits.     

Theoretical study on the reaction mechanism of ozone addition to the double bonds of keto-limonene

The reaction mechanism of ozone (O₃) addition to the double bonds of gas phase keto-limonene was investigated using ab initio methods. Two different possibilities for O₃ addition to the double bond were considered and two corresponding van derWaals complexes (Complex 1 and Complex 2) were found for 1-endo and 2-endo. The rate constants were calculated using the transition state theory at the CCSD(T)/6-31G(d) + CF//B3LYP/6-31G(d,p) level. The high-pressure limit of the total rate constant at 298 K was 3.51 × 10^-16 cm³/(molecule sec), which was in a good agreement with the experimental data.     

柱型水力旋流器对硅切割废砂浆分离性能的研究

为了研究废砂浆中碳化硅粉和硅粉的分离情况,选用混合模型对柱型水力旋流器多相流流场进行数值模拟。模拟结果表明:柱型水力旋流器的分离效率与入口速度、进口浓度等因素有关,并分析出一定条件下当主、次相的入口速度均为1.1m/s时颗粒分离效果较好,分离效率较高,实验检测分离性能较好,为进一步实验研究提供一定的指导。     

Particle number size distribution and new particle formation: New characteristics during the special pollution control period in Beijing

New particle formation is a key process in shaping the size distribution of aerosols in the atmosphere.We present here the measurement results of number and size distribution of aerosol particles (10-1...     

Mechanism of lead immobilization by oxalic acid-activated phosphate rocks

Lead (Pb) chemical fixation is an important environmental aspect for human health. Phosphate rocks (PRs) were utilized as an adsorbent to remove Pb from aqueous solution. Raw PRs and oxalic acid-activated PRs (APRs) were used to investigate the effect of chemical modification on the Pb-binding capacity in the pH range 2.0-5.0. The Pb adsorption rate of all treatments above pH 3.0 reached 90%. The Pb binding on PRs and APRs was pH-independent, except at pH 2.0 in activated treatments. The X-ray diffraction analysis confirmed that the raw PRs formed cerussite after reacting with the Pb solution, whereas the APRs formed pyromorphite. The Fourier Transform Infrared spectroscopy analysis indicated that carbonate (CO₃^2-) in raw PRs and phosphate (PO₄^3-) groups in APRs played an important role in the Pb-binding process. After adsorption, anomalous block-shaped particles were observed by scanning electron microscopy with energy dispersive spectroscopy. The X-ray photoelectron spectroscopy data further indicated that both chemical and physical reactions occurred during the adsorption process according to the binding energy. Because of lower solubility of pyromorphite compared to cerussite, the APRs are more effective in immobilizing Pb than that of PRs.     

氨法烟气脱硫循环液沉降试验研究

通过湿法烟气脱硫副产硫酸铵生产工艺中的循环母液混凝试验,讨论母液的沉降性能,初步探讨母液被循环浓缩的程度对混凝处理效果的影响。