氧化还原条件下有机物料对酸性土壤pH、铁形态和铜吸附解吸的影响

研究了添加有机物料对水稻土、红壤和砖红壤在干湿交替一次以后土壤pH、铁的形态和对铜吸附解吸行为的影响。结果表明,添加有机物料使得土壤pH升高,且随着有机物料加入量的增加而升高。与对照相比,添加有机物料可使水稻土、红壤和砖红壤的pH分别上升1.55、0.8和1.33个pH单位。红壤和砖红壤中无定形氧化铁含量增加,而水稻土中变化不大。在铜的平衡浓度为0.2 mmol/L时,添加有机物料培养可使水稻土、红壤和砖红壤铜的吸附量分别增加6.7、10.3和3.6 mmol/kg。

Scandium recovery from raffinate copper leach solution as potential new source with ion exchange method

Raffinate copper leach solution of the Iran Sarcheshmeh copper complex has up to 3 mg/L scandium(Sc),which is significantly better than many existing sources,making it a possible source for the recovery of Sc using the ion exchange method.Visual Minteq software was employed to ascertain the ionic species likely to be formed under operational conditions in the mine and for selecting the suitable ion exchange resin.The cationic resin thus chosen was employed statically with ions-bearing synthesized solutions and statically/dynamically for actual copper mining raffinate solution.Room temperature and pH of 1.5 showed the highest Sc adsorption.The dynamic tests established the full saturation of the resin at 450 BV of the raffinate solution flow.Using sodium carbonate for elution,desorption of Sc,Y and Ce from the resin during static elution tests at constant duration was higher than that of Fe,Al and Cu.The results from the dynamic tests followed similar trends for the priority and the extent of the elution process.Desorption results from specimens of dynamic tests show a 60:1 concentration ratio leading to a 186 mg/L Sc-rich solution.

Research of Adsorption and Desorption Characteristics of Cu and Pb in Typical Paddy Soils in Jiangxi Province

[Objective] This study was conducted to investigate the adsorption and desorption characteristics of Cu and Pb in typical paddy soils in Jiangxi Province. [Method] Two kinds of typical paddy soils （Gley type, Waterloggogenic type） in Jiangxi Province were chosen as test materials. The single and competitive adsorption behaviors of Cu and Pb in paddy soils were investigated with batch equilibrium method, and the environmental risk under coexistence of Cu and Pb in these soils was estimated with distribution coefficient. The results showed that under equal proportion, the adsorption affinity of Pb was greater than that of Cu in the two paddy soils, and the adsorption capacities in waterloggogenic paddy soil （WPS） were significantly higher than those in gley paddy soil （GTPS）, but the desorption capacities of Cu were greater than those of Pb in the two paddy soils, and the desorption capacities in GTPS were significantly higher than those in the WPS. The adsorption capacities of Cu and Pb ions under competitive condition were obviously lower than those in single system, while the desorption rates significantly increased. The potential environmental risk of Cu pollution was greater than that of Pb in paddy soils, and their environmental risk decreased with the increase of pH, but increased significantly under coexistence of lead and copper. [Conclusion] This research suggests that when Cu and Pb ions coexist in the paddy soils, compared with lead pollution, we should pay attention to the pollution of Cu.

Adsorption of H2O, OH, and O on CUCl（111） Surface： A Density Functional Theory Study

The adsorption of H2O molecule and its dissociation products, O and OH, on CuCl（111） surface was studied with periodic slab model by PW91 approach of GGA within the framework of density functional theory. The results of geometry optimization indicate that the top site is stable energetically for H2O adsorbed over the CuCl（111） surface. The threefold hollow site is found to be the most stable adsorption site for OH and O, and the calculated adsorption energies are 309.5 and 416.5 kJ/mol, respectively. Adsorption of H20 on oxygen-precovered CuCl（111） surface to form surface hydroxyl groups is predicted to be exothermic by 180.1 kJ/mol. The stretching vibrational frequencies, Mulliken population analysis and density of states analysis are employed to interpret the possible mechanism for the computed results.