Using Chlorine Dioxide to Remove the Fouling of Ultrafiltration Membrane and Control Disinfection By‐Products

Ultrafiltration (UF) can remove natural organic matter (NOM) effectively. Moreover, chlorine dioxide (ClO₂) has been an alternative disinfectant as it forms fewer disinfection by‐products with NOM than chlorination does. Therefore, combining ClO₂ with UF may improve conventional purification processes. In this study, feed water containing humic acid with 4.07 mg/L total organic carbon (TOC) was dosed directly with various amounts of ClO₂ (0, 2, 5, 10, and 15 mg/L) before being filtered through a 5‐kDa UF membrane. With a low dose (2 mg/L ClO₂), UF removed humic acid effectively, as TOC was not detected in the permeate, and the permeate flux increased to about 80% of the initial permeate flux by cross flow. Moreover, the concentrations of ClO, ClO, and trihalomethanes in the permeate were below the United States Environmental Protection Agency guidelines.     

鄂尔多斯白垩系盆地地下水的形成与演化：来自Cl及其同位素36Cl的证据

鄂尔多斯自垩系地下水盆地地处中国西部干旱-半干旱地区,其南部和北部分别被黄土和沙漠覆盖,地下水水化学组成在区域上差异显著,北部以淡水为主,南部以微咸-半咸水为主.在沙漠区和黄土区的深层含水层中(埋深大于400 m)分别采集了5组和3组水化学同位素样品.T和14C的分析结果表明,地下水的滞留时间在20343 a内,并且未...     

静电自组装制备斜发沸石负载纳米TiO2吸附及光催化降解甲基橙染料研究

为了实现纳米TiO2的固定化负载,提高材料对污染物的光催化效率,采用静电自组装方法制备了天然斜发沸石负载纳米TiO2光催化材料。采用硅烷偶联剂(OCH3)3Si(CH2)3SH干法改性斜发沸石,采用30%H2O2/HOAc氧化剂将偶联剂巯基基团(—SH)氧化为易电离的磺酸基基团(—SO3H),带负电荷的沸石与钛聚合阳离子在静电引力的作用下自发地组装在一起,经一定温度的焙烧得到斜发沸石负载纳米TiO2光催化材料。采用XRD和SEM对材料进行分析和表征,采用甲基橙染料评价材料的吸附和光催化性能,结果表明:沸石负载纳米TiO2对甲基橙染料具有吸附与光催化的协同作用,静电自组装方法制备的材料的光催化性能较传统方法有所提高。     

Effects of residual chlorine on the mortality, grazing and respiration of Labidocera euchaeta (Copepoda)

In this study,the authors investigated the effects of residual chlorine on mortality,grazing and respiration of Labidocera euchaeta in laboratory.The grazing rate was evaluated by subtraction method of food concentration and respiration rate was measured using oxygen electrode.It was found that the lethal effect of residual chlorine on L.euchaeta increased with enhanced concentration and prolonged duration.The medium lethal concentration (LC 50 ) of chlorine for L.euchaeta in 24 h was about 0.58 mg/L and the safe concentration was about 0.21 mg/L.However,the grazing and respiration of L.euchaeta decreased by 32.6% and 18.9% when exposed to 0.2 mg/L residual chlorine for 4 h.It indicated that the physiological activities of zooplankton could be suppressed by the residual chlorine less than the safety concentration.Therefore,both survival and physiological activities of the organisms living in the thermal (nuclear) power plant discharging waters should be considered when carrying out the ecological risks assessment.     

Calculation of CO2 column heights in depleted gas fields from known pre-production gas column heights

Depleted gas fields have been identified as potential targets for CO₂ storage. In order to maximise storage capacity, a target field must be deep enough to ensure that the CO₂ is in a dense phase (either liquid or supercritical). Accurate assessment of the storage capacity also requires an estimation of the amount of CO₂ that can be safely stored beneath the reservoir seal which can be estimated in several ways. In this paper we develop a methodology to convert known pre-production gas column heights into CO₂ column heights in order to estimate storage capacities. Several authors have correctly identified that the differences in interfacial tension and wettability act to reduce the threshold capillary entry pressure for CO₂ compared to natural gas, consequently reducing column height estimates. However, under reservoir conditions the density of CO₂ is substantially higher than natural gas so the buoyancy force on the seal for a fixed column height is much lower for dense phase CO₂ increasing column height estimates; we investigate the effects of this trade off on storage estimates and apply it to a typical dataset, in this case the UK North Sea.     

二氧化碳—水体系的拉曼光谱研究

研究了使用石英管熔融封闭法分别在酸性、中性以及碱性条件下,采用ＣａＣＯ３或Ｎａ２ＣＯ３与ＨＣｌ反应制备不同浓度的ＣＯ２标准系列,并对气相、液相中的ＣＯ２进行拉曼光谱研究,得出了定量分析气相ＣＯ２所遵循的规律,即ＣＯ２的浓度与拉曼位移（１３８８．９ｃｍ－１）强度呈线性相关,为定量分析流体包裹体中ＣＯ２的含量奠定了基础。     

Soil acidification stimulates the emission of ethylene from temperate forest soils

Soil acidification via acid precipitation is recognized to have detrimental impacts on forest ecosystems, which is in part associated with the function of ethylene released from the soil. However, the impacts of acidification on the cycling of ethylene in forest soils have not been fully taken into consideration in global change studies. Forest topsoils (0--5 cm) under four temperate forest stands were sampled to study the effects of a pH change on the emissions of ethylene and carbon dioxide from the soils and concentrations of dissolved organic carbon (DOC) released into the soils. Increasing acidification or alkalinization of forest soils could increase concentrations of DOC released into the soils under anoxic and oxic conditions. The ethylene emission from these forest topsoils could significantly increase with a decreasing pH, when the soils were acidified experimentally to a pH<4.0, and it increased with an increasing concentration of DOC released into the soils, which was different from the carbon dioxide emission from the soils. Hence, the short-term stimulating responses of ethylene emission to a decreasing pH in such forest soils resulted from the increase in the DOC concentration due to acidification rather than carbon mineralization. The results would promote one to study the effects of soil acidification on the cycling of ethylene under different forest stands, particularly under degraded forest stands with heavy acid depositions.     

世界油气储层二氧化碳埋存量计算研究

二氧化碳减排问题备受世界瞩目,由于温室气体大量排放而引起的全球气候变暖问题日趋严峻,必须采取积极有效措施.应用CO2提高采收率是埋存CO2的重要途径,CO2提高采收率项目分为混相驱油和非混相驱油,CO2的埋存量决定于储层的性质和提高的采收率数值.通过对二氧化碳埋存计算方法的研究,实现CO2埋存和提高原油产量最大化,改善开发效果.必将为全球生态保护,石油资源的高水平、高效益开发和可持续发展提供理论及实践依据.     

煤中氯赋存形态的试验研究

采用艾氏卡熔样—硫氰酸钾滴定法,对我国41个煤中氯的含量进行测定,并研究了煤中氯含量与挥发分、固定碳、灰分以及碱金属的关系。结果表明,我国煤中氯含量普遍较低,一般为0.1%~0.2%;煤中氯含量与煤的煤化程度有明显关系,煤的变质程度越高,煤中氯的含量越少。煤中氯含量与煤中水分和氟的含量无关。随着煤中碱金属含量的增加,煤中氯含量呈下降趋势,煤中氯与碱金属(Na,K,Ca,Mg)等存在负相关性。煤中氯主要以有机形式存在。     

高分辨率海水表层二氧化碳分压重构以大西洋为例

海洋是自然界中重要的碳汇,海−气二氧化碳通量通常利用大气和海水表层的二氧化碳分压（pCO₂）差进行估算。受制于时空分布不均匀的观测样本和预测数据,目前已有海水表层二氧化碳分压的重构结果在空间分辨率上仍有较大可提升空间。为在高空间分辨率下更好地拟合时空变化,基于表层大洋二氧化碳地图（SOCAT）的海水表层二氧化碳逸度（f CO₂）数据集和遥感卫星等多源数据,利用XGBoost模型建立了海水表层二氧化碳分压值与海洋物理、生物、光学等要素的非线性关系,并根据样本时空频率构建权重模型,最终重构了2000−2018年大西洋0.041 7°×0.041 7°下月度海水表层二氧化碳分压分布。预测结果的相关系数为0.966,均方根误差为8.087 μatm,平均偏差为4.012 μatm,与同类重构结果相比,海水表层二氧化碳分压的时空变化趋势一致性强,且在空间分辨率上具有优势。