de Lourdes Ballinas Ma, Rodríguez de San Miguel Eduardo, de Jesús Rodríguez Ma Teresa, Silva Orlando, Muñoz María, de Gyves Josefina
Departamento de Química Analítica, Facultad de Química, UNAM, Ciudad Universitaria, 04510 México, D.F. México.
Environ Sci Technol. 2004 Feb 1;38(3):886-91. doi: 10.1021/es030422j.
Polymer inclusion membranes (PIMs) based on cellulose triacetate (CTA) and dibutyl butyl phosphonate (DBBP) were tested for arsenic(V) separation from H2SO4 for its recovery from copper electrolytes. Solvent extraction experiments allowed the determination of the As(V)-DBBP and H2SO4-DBBP complexes formed in the organic phase. Application of a transient model to membrane transport experiments in solutions containing only arsenic or H2SO4 indicated that it occurred under a kinetically controlled regime by formation of H3AsO4[DBBP]2 and H2SO4[DBBP] species, respectively. When arsenic and H2SO4 are simultaneously present, the existence of a third species, H3AsO4[DBBP][H2SO4], explains well the fact that As(V) flux decreases and that H2SO4 flux increases. In both cases, a limiting 50% recovery value was obtained. However, active arsenic transport (>50%) is achieved if the H2SO4 concentration gradient is assured (e.g., using a triple-cell configuration). In this way, high arsenic recovery factors (90% in 800 min) were obtained with initial concentrations of 5000 mg/L As(V) and 220 g/L H2SO4. In all membrane systems tested, good As(V) selectivity over copper (up to 30000 mg/L) was attained.
对基于三醋酸纤维素（CTA）和丁基膦酸二丁酯（DBBP）的聚合物包容膜（PIMs）进行了测试，以从硫酸中分离砷（V），用于从铜电解液中回收砷。溶剂萃取实验确定了有机相中形成的As（V）-DBBP和H2SO4-DBBP络合物。将瞬态模型应用于仅含砷或硫酸的溶液中的膜传输实验表明，传输分别是通过形成H3AsO4[DBBP]2和H2SO4[DBBP]物种在动力学控制机制下发生的。当砷和硫酸同时存在时，第三种物种H3AsO4[DBBP][H2SO4]的存在很好地解释了As（V）通量降低和H2SO4通量增加的现象。在这两种情况下，回收率极限值均为50%。然而，如果确保硫酸浓度梯度（例如，使用三室配置），则可实现活性砷传输（>50%）。通过这种方式，在初始浓度为5000 mg/L As（V）和220 g/L H2SO4的情况下，在800分钟内获得了高达90%的高砷回收率。在所有测试的膜系统中，对铜（高达30000 mg/L）具有良好的As（V）选择性。
