电感耦合等离子体发射光谱法测定膨润土中的交换性阳离子钙镁钾钠

对膨润土交换性阳离子和阳离子交换容量的测试是评价膨润土矿的主要指标之一,传统的测定膨润土交换性阳离子通常采用原子吸收光谱法或容量法,操作手续复杂繁琐。本文用氯化铵-乙醇交换液交换出试样中的可交换性阳离子钙、镁、钾、钠,分取蒸至湿盐状,制备成盐酸介质的溶液,电感耦合等离子体发射光谱法测定。通过正交试验确定了最佳实验条件为交换1次,加入25 mL交换液,搅拌30 min,沉淀洗涤2次。分别选择315.887 nm、279.079 nm、766.490 nm、589.592 nm作为钙、镁、钾、钠的分析谱线,绘制的标准曲线中钾、钠的浓度在0～0.6 mmol/L,钙、镁的浓度在0～3.0 mmol/L呈良好的线性关系。方法检出限为0.012～0.048 mmol/100 g。经国家标准物质验证,测定值与标准值吻合,精密度为0.5%～2.5%(RSD,n=11),准确度为-6.1%～10%,加标回收率为97.0%～100.0%。本方法样品处理方法程序简单快速,分析重现性好,克服了传统分析方法测定手续繁琐、时间冗长且成本高等缺点,适用于批量样品的分析。     

四酸溶样-电感耦合等离子体原子发射光谱法测定铁、铜、锌、铅等硫化物矿石中22个元素

本实验应用四酸(硝酸,盐酸,氢氟酸,高氯酸)混合溶矿,电感耦合等离子体原子发射光谱法(ICP-AES)同时测定了铁矿石、铜矿石、铅矿石、锌矿石及多金属矿石样品中Al、Fe、Cu、Pb、Zn、Ca、Mg、K、Na、Sb、Mn、Ti、Li、Be、Cd、Ag、Co、Ni、Sr、V、Mo和S 22个元素量。实验确定了方法的分解条件以及测定元素的检出限及干扰条件。用国家一级标准物质GBW07162(多金属贫矿石)和GBW07163(多金属矿石)进行精密度实验,统计数据显示,结果精密度(RSD)和准确度(RE)都小于10%,而且大多数元素的精密度和准确度在5%范围内。通过标准物质进行方法验证,非单矿物或精矿的一般硫化物矿石的检测结果基本都在标准值的范围内,符合地质矿产开发的要求。本方法具有同时测定元素多、线性范围宽、检出限低等优点,实际使用性强,结果满意。     

Characterization of dissolved organic matter fluorescence in the South Atlantic Bight with use of PARAFAC model: Interannual variability

Systematic water sampling for characterization of chromophoric dissolved organic matter (CDOM) in the coastal South Atlantic Bight, was conducted as part of the long term Coastal Ocean Research and Monitoring Program (CORMP). Water samples were collected during a 3.5 year period, from October 2001 until March 2005, in the vicinity of the Cape Fear River (CFR) outlet and in adjacent Onslow Bay (OB). During this study there were two divergent hydrological and meteorological conditions in the CFR drainage area: a severe drought in 2002, followed by the very wet year of 2003. CDOM was characterized optically by the absorption coefficient at 350 nm, the spectral slope coefficient (S), and by Excitation Emission Matrix (EEM) fluorescence. Parallel Factor Analysis (PARAFAC) was used to assess CDOM composition from EEM spectra and six components were identified: three terrestrial humic-like components, one marine humic-like component and two protein-like components. Terrestrial humic-like components contributed most to dissolved organic matter (DOM) fluorescence in the low salinity plume of the CFR. The contribution of terrestrial humic-like components to DOM fluorescence in OB was much smaller than in the CFR plume area. Protein-like components contributed significantly to DOM fluorescence in the coastal ocean of OB and they dominated DOM fluorescence in the Gulf Stream waters. Hydrological conditions during the observation period significantly impacted both concentration and composition of CDOM found in the estuary and coastal ocean. In the CFR plume, there was an order of magnitude difference in CDOM absorption and fluorescence intensity between samples collected during the drought compared to the wet period. During the drought, CDOM in the CFR plume was composed of equal proportions of terrestrial humic-like components (ca. 60% of the total fluorescence intensity) with a significant contribution of proteinaceous substances (ca. 20% of the total fluorescence). During high river flow, CDOM was composed mostly of humic substances (nearly 75% of total fluorescence) with minor contributions by proteinaceous substances. The impact of changes in fresh water discharge patterns on CDOM concentration and composition was also observed in OB, though to a lesser degree.     

未来不同排放情景下气候变化预估研究进展

概述未来不同排放情景下气候变化预估研究的主要进展。首先,对用于开展气候变化预估研究的不同复杂程度的气候系统及地球系统模式及其模拟能力进行了简要的介绍,指出虽然目前气候系统模式在很多方面存在着较大的不确定性,但大体说来可提供当前气候状况的可信模拟结果;进而介绍了IPCC不同的排放情景,以及不同排放情景下全球与东亚区域气候变化预估的主要结果。研究表明,尽管不同模式对不同情景下未来气候变化预估的结果存有差异,但对未来50～100年全球气候变化的模拟大体一致,即全球将持续增温、降水出现区域性增加。在此基础上,概述了全球气候模式模拟结果的区域化技术,并重点介绍了降尺度方法的分类与应用。同时对气候变化预估的不确定性进行了讨论。最后,对气候变化预估的研究前景进行了展望,并讨论了未来我国气候变化预估研究的重点发展方向。     

氨水提取-电感耦合等离子体发射光谱法测定海洋沉积物中的氯

氯的电离能高,在等离子体中难于解离,通常的电感耦合等离子体发射光谱(ICP-AES)光路不能彻底地将空气排出,使得氯的光波被强烈吸收,很难找出相应的特征谱线因而无法准确测定地质样品中的氯。本文对海洋沉积物样品用10%的氨水在超声振荡器中振荡30 min,即可完全提取其中的氯,用ICP-AES测定,选择分析谱线为725.670 nm,方法检出限为50 μg/g(10σ,稀释因子=100)。用海洋沉积物标准物质GBW 07313、GBW 07315、GBW 07316验证,方法精密度(RSD,n=7)为4.3%~8.6%,测定值与标准值的相对误差为2.9%~4.9%。方法简单快速,准确度高,实现了地质样品中氯的准确测定,能够满足海洋地球化学研究的需要。     

电感耦合等离子体发射光谱法同时测定卤水中锂钠钾钙镁硼硫氯

建立了电感耦合等离子体发射光谱法(ICP-AES)同时测定碳酸盐型、硫酸盐型、氯化物型三种类型卤水中Li、Na、K、Ca、Mg、B、S、Cl等高低含量元素的分析方法。选择仪器最佳的工作条件为射频功率1400W,炬管位置位于-3,载气流量0.60 L/min。确定了各元素测定谱线,使用ICP-AES的双向观测模式、轴向观测模式测定Li、Ca、B、S、Cl以及低含量的K、Mg,径向观测模式测定高含量的Na、K、Mg,可确保卤水中不同含量的元素同时检出。Li、Na、K、Ca、Mg、B、S的检测下限为0.07～3.00 mg/L,Cl的测定下限为165mg/L。方法精密度(RSD,n=10)均小于5%,回收率为92.4%～109.7%。其中Na、K、Mg、S、Cl测定结果与传统方法测定结果基本吻合。     

提高光谱分析微量钽铌结果准确度研究

发射光谱法简单、快速测定矿样中微量钽铌时,主要伴生元素锡对准确测定微量钽铌有辅助作用。改进在钨、铁等元素干扰存在时,钽铌分析线对选择。与化学分析测试结果比对验证后,发现光谱分析微量钽铌准确度得到很大提高,可满足地质找矿品位0.01%的需要。     

Greenhouse gas emissions from global cities under SSP/RCP scenarios, 1990 to 2100

Projections of greenhouse gas (GHG) emissions are critical to enable a better understanding and anticipation of future climate change under different socio-economic conditions and mitigation strategies. The climate projections and scenarios assessed by the Intergovernmental Panel on Climate Change, following the Shared Socioeconomic Pathway (SSP)-Representative Concentration Pathway (RCP) framework, have provided a rich understanding of the constraints and opportunities for policy action. However, the current emissions scenarios lack an explicit treatment of urban emissions within the global context. Given the pace and scale of urbanization, with global urban populations expected to increase from about 4.4 billion today to about 7 billion by 2050, there is an urgent need to fill this knowledge gap. Here, we estimate the share of global GHG emissions driven by urban areas from 1990 to 2100 based on the SSP-RCP framework. The urban consumption-based GHG emissions are presented in five regional aggregates and based on a combination of the urban population share, 2015 urban per capita CO₂eq carbon footprint, SSP-based national CO₂eq emissions, and recent analysis of urban per capita CO₂eq trends. We find that urban areas account for the majority of global GHG emissions in 2015 (61.8%). Moreover, the urban share of global GHG emissions progressively increases into the future, exceeding 80% in some scenarios by the end of the century. The combined urban areas in Asia and Developing Pacific, and Developed Countries account for 65.0% to 73.3% of cumulative urban consumption-based emissions between 2020 and 2100 across the scenarios. Given these dominant roles, we describe the implications for potential urban mitigation in each of the scenario narratives in order to meet the goal of climate neutrality within this century.     

Removal of Aromatic Volatile Organic Compounds in the Sequencing Batch Reactor of Petroleum Refinery Wastewater Treatment Plant

This paper presents a field investigation of aromatic volatile organic compounds (AVOCs) emissions from a sequence batch reactor (SBR) with powdered activated carbon (PAC) to treat the wastewater in a large petroleum refinery plant. AVOC with high Henry's constant preferred to transfer from liquid‐phase into air‐phase so that might cause the emission and odor problem. During SBR operation, AVOC concentrations and distributions in wastewater, sludge and off‐gas were analyzed. The total AVOC removal from wastewater was >99% under the kinetic parameters of SBR operated. Batch experiments were carried out in the laboratory to obtain the adsorptive characteristic of AVOC onto PAC, but the results showed that bio‐degradation was the main removal mechanism (85%). Nevertheless, off‐gas emission (<1%) and AVOC in the sludge (<0.1%) remained a stable level. Oxidation/reduction potential (ORP) was correlated to the logarithm of the dissolved oxygen (DO) concentration in a linear relationship so that ORP profile could indirectly reflect the DO and biomass concentrations. Since the influent AVOC concentration was varied and difficultly to measure, ORP could be used as real‐time parameter for optimizing SBR operation. The results provided useful information for future evaluation of AVOC emissions from wastewater treatment plants.     

IPCC emission scenarios: How did critiques affect their quality and relevance 1990–2022?

Long-term global emission scenarios enable the analysis of future climate change, impacts, and response strategies by providing insight into possible future developments and linking these different climate research elements. Such scenarios play a crucial role in the climate change literature informing the Intergovernmental Panel on Climate Change’s (IPCC) Assessment Reports (ARs) and support policymakers. This article reviews the evolution of emission scenarios, since 1990, by focusing on scenario critiques and responses as published in the literature. We focus on the issues raised in the critiques and the possible impact on scenario development. The critique (280) focuses on four areas: 1) key scenario assumptions (40%), 2) the emissions range covered by the scenarios and missing scenarios (25%), 3) methodological issues (24%), and 4) the policy relevance and handling of uncertainty (11%). Scenario critiques have become increasingly influential since 2000. Some areas of critique have decreased or become less prominent (probability, development process, convergence assumptions, and economic metrics). Other areas have become more dominant over time (e.g., policy relevance & implications of scenarios, transparency, Negative Emissions Technologies (NETs) assumptions, missing scenarios). Several changes have been made in developing scenarios and their content that respond to the critique.