Departamento de Química, Universidade Estadual de Londrina, Rod. Celso Garcia Cid-PR445, Londrina, Paraná, 86051-990, Brazil.
Departamento de Engenharia Elétrica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid-PR445, Londrina, Paraná, 86051-990, Brazil.
Chemosphere. 2017 Aug;181:627-634. doi: 10.1016/j.chemosphere.2017.04.071. Epub 2017 Apr 19.
Selenate and selenite are considered emerging contaminants and pose a risk to living organisms. Since selenium anion species are at low concentration in aquatic environments, materials for its retention are required to enable monitoring. Herein, hydrotalcite was calcined and characterised to investigate sorption and desorption of selenite and selenate in competition with nitrate, sulfate and phosphate. Sorption experiments were carried out in batch system and desorption by sequential dilution. Selenite and selenate concentration remaining after N desorption steps was determined by mass balance. The isotherms were adjusted to the dual-mode Langmuir-Freundlich model (R > 0.99). Maximum sorption capacity ranged from 494 to 563 meq kg for selenite and from 609 to 659 meq kg for selenate. Sulfate and phosphate ions showed greater competitive effect on the sorption of selenate and selenite, respectively. Low mobilization factors and high sorption efficiency (MF<3%; SE ≈ 100%) indicated that calcined hydrotalcite has the wanted characteristics for retention of relevant selenium anion species in aqueous media.
硒酸盐和亚硒酸盐被认为是新兴污染物，对生物体构成风险。由于硒阴离子在水生环境中的浓度较低，因此需要保留材料以进行监测。在此，煅烧水滑石并进行了表征，以研究其与硝酸盐、硫酸盐和磷酸盐竞争时对亚硒酸盐和硒酸盐的吸附和解吸作用。吸附实验在分批系统中进行，解吸通过顺序稀释进行。通过质量平衡确定 N 解吸步骤后剩余的亚硒酸盐和硒酸盐浓度。等温线被调整为双模式朗缪尔-弗伦德利希模型（R > 0.99）。亚硒酸盐的最大吸附容量范围为 494 至 563 meq kg，而硒酸盐的最大吸附容量范围为 609 至 659 meq kg。硫酸盐和磷酸盐离子对硒酸盐和亚硒酸盐的吸附分别表现出更大的竞争作用。低迁移因子和高吸附效率（MF<3%；SE ≈ 100%）表明煅烧水滑石具有在水介质中保留相关硒阴离子的理想特性。
