Coordination configurations of cupric tartrate in electronic industry wastewater
(1. Key Laboratory of Hunan Province for Clean and Efficient Utilization of Strategic Calcium-containing Mineral Resources, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;
2. Suzhou Dongfang Environmental Engineering Co., Ltd., Suzhou 215110, China;
3. Key Laboratory of Hunan Province for Comprehensive Utilization of Complex Copper-Lead Zinc Associated Metal Resources, Hunan Research Institute for Nonferrous Metals, Changsha 410100, China;
4. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China)
2. Suzhou Dongfang Environmental Engineering Co., Ltd., Suzhou 215110, China;
3. Key Laboratory of Hunan Province for Comprehensive Utilization of Complex Copper-Lead Zinc Associated Metal Resources, Hunan Research Institute for Nonferrous Metals, Changsha 410100, China;
4. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China)
Abstract: The coordination structure of cupric tartrate (Cu-TA) complex was investigated by ultraviolet-visible (UV-Vis) and liquid chromatography/mass spectrometer (LC-MS) firstly; furthermore, effective coordination configurations and electronic properties of Cu-TA in aqueous solution were systematically revealed by density functional theory (DFT) calculations. Consistently, Job plots show the possible existence of [Cu(TA)] and [Cu(TA)2]2- at 230 and 255 nm based on UV-Vis results. LC-MS results confirm the existence of the single and high coordination complexes [Cu2(TA)2]+, [Cu(TA)2]+ and [Cu2(TA)3(H2O)2(OH)2]2+. DFT calculation results show that carboxylic oxygen and hydroxyl oxygen of tartaric acid (TA) are preferred sites for Cu(II) coordination. [Cu(TA)] (1H, 3H sites O of TA coordinated with Cu(II)), [Cu(TA)2]2- (two 1C, 2H sites O of TA coordinated with Cu(II)), and [Cu(TA)3]4- (three 2H, 3H sites O of TA coordinated with Cu(II)) should be dominant coordination configurations of Cu-TA. The corresponding Gibbs reaction energies are -170.1, -136.2, and -90.2 kJ/mol, respectively.
Key words: electronic industry wastewater; copper; tartaric acid; cupric tartrate complex; coordination configuration; density functional theory