Climate change and changes in global precipitation patterns: what do we know?

The objective of this paper is to synthesize the large literature recording changing patterns of precipitation in the observed data, thus indicating that climate change is already a reality. Such a synthesis is required not only for environmental researchers but also for policy makers. The key question is the broad picture at major regional and continental levels. Some interesting conclusions for this survey are emerging. For example, the review shows increased variance of precipitation everywhere. Consistent with this finding, we observe that wet areas become wetter, and dry and arid areas become more so. In addition, the following general changing pattern is emerging: (a) increased precipitation in high latitudes (Northern Hemisphere); (b) reductions in precipitation in China, Australia and the Small Island States in the Pacific; and (c) increased variance in equatorial regions. The changes in the major ocean currents also appear to be affecting precipitation patterns. For example, increased intensity and frequency of El Ni?o and ENSO seem associated with evidence of an observed "dipole" pattern affecting Africa and Asia, although this time series is too short so far. But the changing pattern calls for renewed efforts at adaptation to climate change, as the changing precipitation pattern will also affect the regional availability of food supply.     

Removal of Ni(II) from strongly acidic wastewater by chelating precipitation and recovery of NiO from the precipitates

Strongly acidic wastewater produced in nonferrous metal smelting industries often contains high concentrations of Ni(II), which is a valuable metal. In this study, the precipitation of Ni(II) from strongly acidic wastewater using sodium dimethyldithiocarbamate (DDTC) as the precipitant was evaluated. The effects of various factors on precipitation were investigated, and the precipitation mechanism was also identified. Finally, the nickel in the precipitates was recovered following a pyrometallurgical method. The results show that, under optimised conditions (DDTC:Ni(II) molar ratio = 4:1; temperature = 25 °C), the Ni(II) removal efficiency reached 99.3% after 10 min. In strongly acidic wastewater, the dithiocarbamate group of DDTC can react with Ni(II) to form DDTCNi precipitates. Further recovery experiments revealed that high-purity NiO can be obtained by the calcination of DDTCNi precipitates, with the nickel recovery efficiency reaching 98.2%. The gas released during the calcination process was composed of NO₂, CS₂, H₂O, CO₂, and SO₂. These results provide a basis for an effective Ni(II) recovery method from strongly acidic wastewater.     

因子分析法用于降水化学组分地域分布的探讨

本文对成都市区降水化学组分进行了因子分析。通过研究因子计量的空间分布,得到各因子的主要作用区域及降承化学组分的区域分布特征;因子所反映的离子组合关系可能代表某种大气污染源性质或影响降水化学组分的某种物理化学过程。     

味精废水的预处理试验研究

针对味精废水的“五高二低”问题,对其进行了高速离心分离菌体、加石灰水中和沉淀SO24-、离子交换回收谷氨酸联合处理及絮凝沉降+石灰水中和沉淀处理等方法的试验研究,得出采用上述两种联合预处理后,能大部分去除废水中的SS、NH3-N、SO24-,可以满足后续生化处理的要求。在实际应用中如何选用,需结合经济效益与处理效果进行综合分析。     

大气样品中阳离子的离子色谱法测定

用单往离子色谱法测定了降水、TSP、降尘中的一价和二价阳离子(水溶物),方法精密度实验的变异系数≥2.02％;改进了ZIC—ⅡA型离子色谱仪的原流路系统。     

南充炼油化工总厂污水处理技改及运行综述

南充炼油化工总厂污水处理装置从2004年开始进行技术改造，于2005年8月实现了已改设施一次开车成功，各项水质指标均达到并超过设计要求。对技术改造的情况、采用的新技术新工艺做全面介绍，对装置改造后的运行效果进行分析。     

ClO_2氧化,混凝沉降法处理煤气洗涤水的研究

根据煤气洗涤水的性质,用ClO2 氧化除酚,SL和PAM混凝沉降除悬浮物的方法处理煤气洗涤水。实验结果表明,经处理后废水中的主要污染物酚、焦油和悬浮物等去除率都很高,该水完全可以满足回用要求。     

Effect of TiO2 surface properties on the SCR activity of NOx emission abatement catalyst

NOx emission abatement catalysts V2O5 supported on various TiO2 including anatase, rutile and mixture of both were investigated with various physico-chemical measurements such as BET, NH3-TPD, NARP, XRD and so on, and the effect of TiO2 surface properties on the SCR (selective catalytic reduction) activity of V20s/TiO2 catalysts was studied. It was found that the TiO2 surface properties had strong affect on the SCR activity of V2Os/TiO2 catalysts. The stronger acidic property resulted in the higher exposure of active sites as well as the higher SCR activity.     

酸性硫酸盐土的酸度类型及其测定方法

酸性硫酸盐土是一种广泛分布于沿海低地和矿区的污染源土壤，对生态环境和人类健康具有潜在或实际的负面影响。酸性硫酸盐土中各类酸度是评估酸性硫酸盐土环境风险最重要的指标。酸性硫酸盐土的酸度可分为水溶性酸度、吸持性酸度和金属硫化物起源潜在酸度等3种类型。文章根据最新的研究结果，简要地介绍酸性硫酸盐土的酸度类型及其测定方法。     

苯系物Lewis酸碱性定量及其应用

本文以正丁醚／水和环己烷／水分配系数的对数差值Ａ作为酸性指数，以氯仿／水和四氯化碳／水分配系数的对数差值Ｂ作为碱性指数来度量苯系物的Ｌｅｗｉｓ酸碱性，阐明Ａ、Ｂ两指数的物理意义，并表征其相互作用的Ｌｅｗｉｓ酸、碱间的分子作用力的大小，定量分析其与Ｋａｍｌｅｔ等人提出了溶剂化显色参数π，α，β间的关系，研究了各种分子间的对酸，碱性的相对贡献，氢键的贡献是主要的，其次是偶极作用的贡献，色散力引起的贡献