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作者： Xiaoxia Lii gerard j. M. Versteegh j.nming Song Xuegang Li Huamao Yuan Ning Li Faculty of Marine Sciences China University of Geosciences State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Heisenberg Group on Marine Kerogen Center for Marine Environmental Sciences (MARUM) Bremen University Institute of Oceanology Chinese Academy of Sciences

From a large number of case studies on terrestrial deposits we know that Late Holocene climate fluctuations have an important impact on the terrestrial environments. However, it is hitherto not clear how the marine sediments can be used to shed light on the environment and climate change of the catchment. To provide such insight, we used the maj.r element, trace element and rare earth element（REE） compositions in the southern Yellow Sea（SYS） sediments to reconstruct the changes in weathering and erosion of their source regions. The sediments originate predominantly from the upper crust of East China and are transported into the basin especially by the Yellow River（Huanghe） and to a lesser extent by the Yangtze River（Changj.ang）. The chemical index of alteration（CIA; 53.7–59.7） suggests low chemical weathering of the source rocks since the Middle Holocene. This is consistent with the relatively cool and arid climate in North China after the Holocene Megathermal. Comparison of element ratios, including Al/Ca, K/Ca, Al/Na, K/Na, Rb/Sr, Li/Ba and the CIA shows that we can use the latter as a robust proxy for climate change. The CIA-based mean annual precipitation and mean annual temperature show a series of climate fluctuations in the catchment. A relatively warm and humid Period I（5.3–2.9 cal. ka BP）, a relatively cool and dry Period II（2.9–0.9 cal. ka BP） and an increasingly cool and dry Period III（0.9–0.3 cal. ka BP）. These periods can be linked to climate intervals recognized elsewhere.

关键词： geochemical composition elemental ratio climate change provenance South YellowSea sediment.

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Reactive Extraction of Alcohols from Apolar Hydrocarbons with Aqueous Solutions

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Tsinghua Science and Technology 2006年第2期11卷 222-227页

作者： Boris Kuzmanovi Norbert j. M. Kuipers André B. de Haan gerard Kwant Akzo Nobel Chemicals Research Arnhem The Netherlands University of Twente Enschede The Netherlands DSM Research Geleen The Netherlands

The aqueous solutions are evaluated as sustainable reactive extraction solvents for the recovery of monohydroxyl alcohols （benzyl alcohol, 1-hexanol, cyclohexanol） present in few-percent concentrations in apolar hydrocarbons （toluene, n-hexane, and cyclohexane） by considering two approaches. An aqueous solution containing a reactive extractant, like borate salts, borate complexes, a monosalt of dicarboxylic acid, hydroxypropyl-cyclodextrins, and silver nitrate, shows limited potential to be used. Another approach, in which the alcohol is chemically modified prior to the extraction into an easy-extractable form, in this case a monoester/carboxylic acid, shows much more potential. An environmentally benign aqueous solution of sodium hydrogen carbonate can provide a distribution ratio of benzyl alcohol up to 200, leaving the solubility of the organic solvent in the aqueous solution unchanged relative to pure water and therefore increasing the selectivity with two orders of magnitude. The modification of aromatic, cyclo-aliphatic, and linear aliphatic alcohols can be performed efficiently in the apolar organic solvent without need for a catalyst. The recovery of the modified alcohol can be performed by back-extraction in combination with a spontaneous hydrolysis.

关键词： reactive extraction alcohol polar hydrocarbons

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