Speciation of Al and Cd in Aqueous Solutions: Association Quotients of Oxalate and Malonate Complexes

9317075凯特勒尽管铝和镉的化学对地质科学很重要，但对它们的草酸盐和丙二酸络合物的缔合商的测量很少。研究人员将测量草酸铝、丙二酸铝、Cd-草酸盐和Cd-丙二酸络合物在离子强度从0.1到5m的溶液中和在0-125℃的温度范围内的缔合商。这些测量将使用电位滴定方法，将草酸盐或丙二酸盐溶液滴定到Cd或Al的水溶液中。采用三氟甲磺酸钠作为非络合支持电解质。在这些滴定过程中获得的数据将被回归，并将推导出相关的缔合常数与温度和离子强度之间的关系式。铝是地壳中第三丰富的元素。与硅酸盐矿物的溶解以及酸雨对环境和公众健康的影响有关的问题从根本上说是水溶液中铝的形态问题。虽然Cd是一种痕量金属，但它的毒性及其在垃圾渗滤液、污水污泥、硫化物矿床和化石贝壳中的普遍存在，使其具有重要的环境和地质意义。草酸和丙二酸是双官能团的羧酸阴离子，与金属形成强烈的络合物。这些酸性阴离子普遍存在于土壤和提高采油和合成燃料作业过程中产生的副产品水中。它们也可能大量存在于一些沉积盆地卤水中。这项工作应该会引起地质和环境科学中各种研究人员的兴趣。

9317075 Kettler Despite the importance of Al and Cd chemistry to the geological sciences there are few measurements of the association quotients of their oxalate and malonate complexes. The investigator will measure the association quotients of Al-oxalate, Al-malonate, Cd-oxalate, and Cd-malonate complexes in solutions with ionic strengths ranging from 0.1 to 5m and at temperatures ranging from 0-125 C. These measurements will be made using potentiometric methods by titrating oxalate or malonate solutions into aqueous solutions of Cd or Al. Na-trifluoromethanesulfonate will be used as a non-complexing supporting electrolyte. The data obtained during these titrations will be regressed and equations relating the relevant association constants to temperature and ionic strength will be derived. Al is the third most abundant element in the earth's crust. Problems related to the dissolution of silicate minerals and the environmental and public health effects of acid rain are fundamentally problems of al speciation in aqueous solutions. Although Cd is a trace metal, its toxicity and its ubiquity in landfill leachates, sewage sludge, sulfide ore deposits, and fossil shells give it great environmental and geologic importance. Oxalate and malonate are difunctional carboxylic acid anions that form strong complexes with metals. These acid anions are ubiquitous in soils and the by-product waters produced during enhanced oil recovery and synthetic fuels operations. They may also be present in large amounts in some sedimentary basin brines. This work should be of interest to a wide variety of researchers in the geological and environmental sciences.