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

水溶液中铝和镉的形态：草酸盐和丙二酸盐络合物的缔合商

• 批准号: 9317075
• 负责人: Richard Kettler
• 金额: $ 7.05万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-01-15 至 1996-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9317075&HistoricalAwards=false
• 关键词: Speciation; Al; Cd; Aqueous; Solutions

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.

小行星9317075 尽管铝和镉化学在地质科学中具有重要意义，但它们的草酸盐和丙二酸盐络合物的缔合物的测量却很少。 研究者将在离子强度范围为0.1 - 5 m和温度范围为0-125 ℃的溶液中测量铝-草酸盐、铝-丙二酸盐、镉-草酸盐和镉-丙二酸盐络合物的缔合物。 这些测量将使用电位滴定法通过滴定草酸盐或丙二酸盐溶液到镉或铝的水溶液。钠-三氟甲磺酸盐将被用作非络合支持电解质。 在这些滴定过程中获得的数据将回归和方程相关的缔合常数的温度和离子强度将推导出来。 铝是地壳中第三丰富的元素。 与硅酸盐矿物的溶解和酸雨对环境和公众健康的影响有关的问题是水溶液中铝形态的根本问题。 虽然镉是一种微量金属，但它的毒性及其在垃圾填埋场渗滤液、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。 草酸根和丙二酸根是与金属形成强络合物的双官能羧酸阴离子。 这些酸性阴离子普遍存在于土壤和强化采油和合成燃料作业过程中产生的副产物沃茨中。 它们也可能大量存在于某些沉积盆地卤水中。 这项工作应该是感兴趣的各种各样的研究人员在地质和环境科学。