Elements of Carbon Balance in Oligotrophic Bogs

Elements of carbon balance of oligotrophic bogs were studied using an example of the landscape profile of the Klyuch River in 1998–2000. Carbon balance was preliminarily calculated taking into account the biological productivity, release of carbon dioxide and methane, and carbon outflow with bog waters. Based on the data obtained on the carbon inflow and outflow, the conclusion was made concerning the progressive peat formation in the region studied.     

Preparation and performance of photocatalytic regenerationable activated carbon prepared via sol-gel TiO2

Preparation of photocatalytic regenerationable activated carbon （AC） is the key step for the practical application of in situ regeneration of exhausted AC. A novel photocatalytic regenerationable AC was prepared by sol-gel TiO2 in this work. The adsorption and regeneration performance of TiO2/AC were evaluated using phenol as model compound. Scanning electron microscope （SEM） and nitrogen （77 K） adsorption isotherm were used to determine the surface area, pore structure and the distribution of TiO2. The results showed that with the increase of TiO2 loading, adsorption capacity of TiO2/AC decreased and the regeneration efficiency increased. The photocatalytic regenerationable AC with suitable TiO2 loading （2 wt%） exhibited suitable adsorption capacity and regeneration efficiency. TiO2 located mainly in the entrance of macro-pore of carbon. The prepared TiO2/AC exhibited similar surface structure and pore structure with material carbon.     

Arsenic contamination in the Kanker district of central-east India: geology and health effects

This paper identifies newer areas of arsenic contamination in the District Kanker, which adjoins the District Rajnandgaon where high contamination has been reported earlier. A correlation with the mobile phase episodes of arsenic contamination has been identified, which further hinges on the complex geology of the area. Arsenic concentrations in both surface and groundwater, aquatic organisms (snail and water weeds) soil and vegetation of Kanker district and its adjoining area have been reported here. The region has been found to contain an elevated level of arsenic. All segments of the ecoysystem are contaminated with arsenic at varying degrees. The levels of arsenic vary constantly depending on the season and location. An analysis of groundwater from 89 locations in the Kanker district has shown high values of arsenic, iron and manganese (mean: 144, 914 and 371 μg L⁻¹, respectively). The surface water of the region shows elevated levels of arsenic, which is influenced by the geological mineralised zonation. The most prevalent species in the groundwater is As(III), whereas the surface water of the rivers shows a significant contamination with the As(V) species. The analysis shows a bio-concentration of the toxic metals arsenic, nickel, copper and chromium. Higher arsenic concentrations (groundwater concentrations greater than 50 μg L⁻¹) are associated with sedimentary deposits derived from volcanic rocks, hence mineral leaching appears to be the source of arsenic contamination. Higher levels of arsenic and manganese in the Kanker district have been found to cause impacts on the flora and fauna. A case study of episodic arsenical diarrhoea is presented.     

Photochemical oxidation of reduced sulfur compounds in an urban location based on short time monitoring data

This study examines the oxidation of reduced sulfur compounds (RSCs) in urban ambient air. The photochemical conversions of RSC (such as DMS, CS₂, H₂S, DMDS, and CH₃SH) to a further oxidized form (e.g., SO₂, MSA, and H₂SO₄) were assessed using a photochemical box model. For our model simulation of RSC oxidation, measurements were taken at an urban monitoring station in Seoul, Korea (37.6° N, 127° E) during three separate time periods (e.g., Sept. 17–18, Oct. 23, and Oct. 27–28, 2003). The results indicate that DMS and H₂S were the dominant RSCs with concentrations of 370 ± 140 and 110 ± 60 pptv, respectively. The photochemical conversion of DMDS to SO₂ was found to occur more efficiently than other RSCs. The overall results of our study suggest that photochemical conversion of RSCs accounted for less than 15% of the observed SO₂ during the measurement period. The SO₂ production from DMS oxidation (mainly by the reaction with OH) was found to be affected primarily by the abstraction channel due to high NO_x levels during the experimental conditions.     

矿用救生舱内二氧化碳净化特性研究

煤矿救生舱是在矿井下发生事故后保护被困矿工生存、等待救援的密闭舱室设备。在救援过程中,二氧化碳的处理是舱内空气净化系统的一项主要功能。本文对救生舱内二氧化碳净化装置的功率、吸收效率、药剂床层厚度等因素进行了一系列试验,确定了救生舱二氧化碳的最优净化方式,并通过救生舱内真人生存试验对其进行了验证。最终得出救生舱内处理二氧化碳最佳反应条件为:药剂量20kg,最佳功率为100W;间歇式工作的运行时间与停机时间比例为2:3;在救生舱内8人生存模拟实验中,得出8kg药剂可供8人使用6.1h,平均吸收速率为1.34L/min。     

伊宁市空气中硫酸盐化速率与二氧化硫相关性研究

对伊宁市1999-2002年空气中硫酸盐化速率和二氧化硫监测值进行回归分析,结果表明,二者之间存在显著的线性正相关关系,但对各年度回归方程斜率和截距进行统计检验,则表现出显著的差异。     

膜吸收器吸收CO2的影响因素研究

采用聚丙烯中空纤维膜吸收器,用水、NaOH和K2CO3 水溶液作为吸收剂进行高浓度CO2 吸收试验,考察了气体流率、吸收剂流率、质量分数以及流动方式对吸收率、传质系数和传质速率的影响.结果表明,随着气体流率增大,CO2的吸收率递减,总传质系数和总传质速率增加.在一定的气体流率下,吸收液流率增大,CO2的吸收率、总传质系数和总传质速率增大;吸收液浓度提高,吸收率增大,总传质系数和总传质速率提高.在气体流率较低时,质量分数为5%和8%的NaOH水溶液为吸收剂时的吸收率、总传质系数和总传质速率比较接近.随着气体流率增大,NaOH质量分数为8%时的吸收率、总传质系数和总传质速率增加的值大大超过NaOH质量分数为5%时增加的值.以水为吸收剂时,气体与吸收剂的流动方式为逆流时的吸收率、总传质系数和总传质速率高于并流时的值.     

光活性二氧化钛膜的制备方法

近二十年来发展起来的光催化技术可利用太阳光能对水体中的多种有机污染物进行降解．这符合可持续发展的长远需要,具有诱人的发展前景。光催化技术利用可再生的清洁资源,氧化能力强．适用于广谱有机物,能使难被一般氧化剂氧化、又难生物降解的污染物降解．是当前太阳能利用及水污染控制方面开辟的前沿领域．在治理环境污染方面具有明显的发展优势。本文以溶胶-凝胶法、金属有机化学气相淀积、煅烧沉淀法等多种方法制备光活性二氧化钛膜。     

Accounting for the effect of concentration fluctuations on toxic load for gaseous releases of carbon dioxide

In Great Britain, advice on land-use planning decisions in the vicinity of major hazard sites and pipelines is provided to Local Planning Authorities by the Health and Safety Executive (HSE), based on quantified risk assessments of the risks to the public in the event of an accidental release. For potential exposures to toxic substances, the hazard and risk is estimated by HSE on the basis of a “toxic load”. For carbon dioxide (CO₂), this is calculated from the time-integral of the gas concentration to the power eight. As a consequence of this highly non-linear dependence of the toxic load on the concentration, turbulent concentration fluctuations that occur naturally in jets or plumes of CO₂ may have a significant effect on the calculated hazard ranges. Most dispersion models used for QRA only provide estimates of the time- or ensemble-averaged concentrations. If only mean concentrations are used to calculate the toxic load, and the effects of concentration fluctuations are ignored, there is a danger that toxic loads and hence hazard ranges will be significantly under-estimated.This paper explores a simple and pragmatic modification to the calculation procedure for CO₂ toxic load calculations. It involves the assumption that the concentration fluctuates by a factor of two with a prescribed square-wave variation over time. To assess the validity of this methodology, two simple characteristic flows are analysed: the free jet and the dense plume (or gravity current). In the former case, an empirical model is used to show that the factor-of-two approach provides conservative estimates of the hazard range. In the latter case, a survey of the literature indicates that there is at present insufficient information to come to any definite conclusions.Recommendations are provided for future work to investigate the concentration fluctuation behaviour in dense CO₂ plumes. This includes further analysis of existing dense gas dispersion data, measurements of concentration fluctuations in ongoing large-scale CO₂ release experiments, and numerical simulations.     

基于ARCGIS的水泥行业碳排放点源分布与变化分析

首先对水泥行业产能与产量数据进行调研,对不同的工艺采用不同的CO2排放因子系统地计算了2000—2009年各点源企业水泥生产的CO2排放量,在点源企业排放量数据的基础上分析计算了各省份及全国总排放量的年度增长趋势。其次利用ARCGIS绘制了全国水泥行业排放点源年度分布图并分析了其空间分布特征,调查分析了我国水泥企业CO2排放源点源分布与变化规律,对水泥工业节能减排、发展低碳经济的工作具有重要的意义。