Preparations of TiO2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni^2＋ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.     

大型钢铁企业典型工序碳排放系数的确定方法探讨

为准确合理地确定适合于钢铁行业实际的碳排放系数,通过碳平衡算法求出了各工序的碳排放量,然后按碳排放系数的定义反算出了各工序的碳排放系数.同时,通过对某大型钢铁企业焦化、烧结、炼铁3个典型工序的原料产能的实测数据调查,首先基于碳平衡方程计算出典型工序的碳排放量,然后由碳排放量计算其碳排放系数.最后以该大型钢铁企业2009年的调查数据为例,按本方法计算出的焦化、烧结、炼铁工序的碳排放系数分别为0.518、0.210、1.375,与IPCC提供的默认值(0.56、0.20、1.35)极为吻合.这一结果表明,该方法用于我国钢铁行业碳排放系数体系的建立是可行的.     

POST‐HARVEST RIPARIAN BUFFER RESPONSE: IMPLICATIONS FOR WOOD RECRUITMENT MODELING AND BUFFER DESIGN1

Despite the importance of riparian buffers in providing aquatic functions to forested streams, few studies have sought to capture key differences in ecological and geomorphic processes between buffered sites and forested conditions. This study examines post‐harvest buffer conditions from 20 randomly selected harvest sites within a managed tree farm in the Cascade Mountains of western Washington. Post‐harvest wind derived treefall rates in buffers up to three years post‐harvest averaged 268 trees/km/year, 26 times greater than competition‐induced mortality rate estimates. Treefall rates and stem breakage were strongly tied to tree species and relatively unaffected by stream direction. Observed treefall direction is strongly biased toward the channel, irrespective of channel or buffer orientation. Fall direction bias can deliver significantly more wood recruitment relative to randomly directed treefall, suggesting that models that utilize the random fall assumption will significantly underpredict recruitment. A simple estimate of post‐harvest wood recruitment from buffers can be obtained from species specific treefall and breakage rates, combined with bias corrected recruitment probability as a function of source distance from the channel. Post‐harvest wind effects may reduce the standing density of trees enough to significantly reduce or eliminate competition mortality and thus indirectly alter bank erosion rates, resulting in substantially different wood recruitment dynamics from buffers as compared to unmanaged forests.     

基于硫酸根自由基的高级氧化对头孢氨苄的降解特性

采用高级氧化(advanced oxidation processes, AOPs)技术去除水体中的头孢类抗生素。选取头孢类抗生素中的典型物质头孢氨苄(CFX)为研究对象,探讨了其在UV/过硫酸盐(UV/PS)体系中的降解特性。结果表明,pH=7.0时,UV/PS体系中SO4-·和·OH均对CFX有降解作用,且其与CFX反应的二阶速率常数分别为9.8±0.4×109L?(mol?s)-1、1.05±0.7×1010L?(mol?s)-1。PS投加量的增加可加速CFX的降解和矿化,且酸性条件可促进CFX降解。水体基质Cl-的存在对CFX的降解起到了低浓度抑制高浓度促进的作用,HCO3-和自然有机质(NOM)的存在对CFX的降解稍有抑制。在实际水样中的应用研究表明,UV/PS体系可以有效降解和矿化实际地表水样(SW)和实际废水样(WW)中的CFX,具有较好的应用前景。     

UV/O3降解水样中COD的动力学建模

建立动力学模型可以对UV/O3降解有机物的过程进行有效的分析和预测,帮助改进水处理工艺以提高有机物的降解效率和降低能源消耗。然而,已有的方法无法满足实际水样中未知有机物降解过程的建模需求。在化学反应机理的基础上,结合对有机物降解生成CO2浓度演化规律的分析,建立了一种可预测未知有机物降解反应的数学模型。通过改变氧化消解的条件,从理论上检验了该模型的灵敏度;同时,实验采用了含有葡萄糖、尿素和邻苯二甲酸氢钾的混合溶液作为测试水样,考察了模型的准确性,实验值与预测值的趋势一致。     

How do different process options and evaluation settings affect economic and environmental assessments? A case study on methyl methacrylate (MMA) production processes

We present an investigation on how economic and environmental assessment results change when different process options or evaluation settings are considered. As the main case study the production technology of methyl methacrylate (MMA) is investigated. Six commercial processes using different reaction routes are modelled and evaluated with respect to their economic and environmental performance. On these six base case models different process options and evaluation settings are considered and the resulting impacts on the assessment results are quantified. Major findings of the study are that the more decision-variables become fixed, the smaller becomes the impact of the decisions still to be taken—but not only with respect to the economic performance but also with regard to the environmental assessment result. Along the process development steps the potential impacts on the economic and environmental performance decrease to the same degree. The results obtained for the evaluation settings do not show such a systematic pattern as those for the process options. This finding indicates that decision makers face many options in the economic and especially the environmental assessment of chemical processes which might lead to quite different magnitudes in variability due to either the choice of method or the choice of method parameters. This paper demonstrates that the resulting variability might be crucial with respect to the decision making outcome.     

景观带尺度高寒区水文特征时空变化规律研究

目前高寒区景观带尺度水文规律的研究还非常薄弱.同位素技术被用来甄别高寒区不同景观带冰川、积雪、冻土、地表水、地下水和降雨等对径流的贡献组合及其时空变化规律,旨在揭示各景观带的水文规律.结果表明马粪沟流域雨季降雨量大,温度效应显著,易发生再次蒸发,致使各水体δ18O和δD较高.干季气温低,降水多为固态,蒸发弱,不易受到再次蒸发和周围水汽交换影响,致使各水体δ18O和δD相对偏负.降雨和各水体在雨季富集重D和18O,干季较贫重同位素,存在季节效应.降雨存在高程效应,δ18O=-0.005 2 H-8.951,R=-0.917 2;δD=-0.018 5 H-34.873,R=-0.876 3.流域各景观带各水体在雨季和干季均不存在高程效应,是因为出山径流均非以降雨直接补给为主,受冰川、积雪和冻土等冻融过程影响,降水、融水、地表水与地下水等相互转化,导致同位素特征发生变化,混合和蒸发效应是其同位素变化的主要控制因素.     

苯酚液相臭氧氧化和复合氧化反应动力学

推导了苯酚液相臭氧氧化和复合氧化（O3/H2O2）反应动力学模型,研究了苯酚液相臭氧氧化和复合氧化过程的降解,得出了苯酚液相臭氧氧化和复合氧化在温度288～313K和pH3.2～9.8条件下的反应动力学,探讨了反应机理,认为：在酸性(pH3.2）及弱酸性（pH6.2～6.5）时,苯酚的臭氧化和复合氧化降解反应均为O3分子的直接氧化过程;在碱性（pH9.8）条件下,苯酚复合氧化降解机理以自由基反应为主。     

钻井废弃泥浆随钻处理技术应用

介绍了钻井废弃泥浆随钻（边钻边处理）处理技术应用的过程及效果。现场应用情况表明,钻井废弃泥浆随钻处理技术是一种科学有效的钻井废液处理技术,在钻井工程施工过程中可以减少临时土地占用、减少土壤污染、保护环境。