College of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China; Shaanxi Key Laboratory of Green Preparation and Functionalization of Inorganic Materials, Xi'an 710021, China.
College of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China; Shaanxi Key Laboratory of Green Preparation and Functionalization of Inorganic Materials, Xi'an 710021, China.
Sci Total Environ. 2020 Jun 10;720:137391. doi: 10.1016/j.scitotenv.2020.137391. Epub 2020 Feb 19.
Ethylenediaminetetraacetic acid modified attapulgite (EDTA-ATP) was developed as a novel and promising adsorbent for removal of aqueous Cr(Ш). The structure and surface properties of EDTA-ATP were characterized and the results indicated that EDTA moieties have been successfully anchored on the surface of ATP. Adsorption of Cr(III) on EDTA-ATP and aminopropyl-modified attapulgite (APTES-ATP) monotonously reduced with decreasing pH, and Cr(III) adsorption on EDTA-ATP is substantially higher than APTES-ATP in tested pH range, especially at lower pH. Presence of citric acid and gelatin had no obvious influence on Cr(III) adsorption to EDTA-ATP, but significantly reduced Cr(III) adsorption on APTES-ATP. Coexisting cations resulted in decreased Cr(III) adsorption on EDTA-ATP by competition with Cr(III) for surface-bound EDTA groups of the adsorbent. Adsorption isotherm of Cr(III) on EDTA-ATP followed the Langmuir model and the maximum adsorption capacity of the adsorbent for Cr(III) was 131.37 mg/g at 25 °C and pH 3.0. Cr(Ш) loaded adsorbent could be regenerated easily in HCl solution and the regenerated adsorbent still exhibited high adsorption capacity for Cr(III). XPS analysis confirmed that the enhanced Cr(III) adsorption on EDTA-ATP was ascribed to form the stable complexes between Cr(III) and surface-bound carboxyl and amino groups of the adsorbents.
乙二胺四乙酸修饰凹凸棒石（EDTA-ATP）被开发为一种新型且有前途的吸附剂，用于去除水溶液中的 Cr(Ш)。对 EDTA-ATP 的结构和表面性质进行了表征，结果表明 EDTA 部分已成功锚定在 ATP 的表面上。Cr(III)在 EDTA-ATP 和氨丙基修饰凹凸棒石（APTES-ATP）上的吸附随 pH 的降低而单调降低，在测试的 pH 范围内，Cr(III)在 EDTA-ATP 上的吸附显著高于 APTES-ATP，尤其是在较低的 pH 下。柠檬酸和明胶的存在对 EDTA-ATP 上 Cr(III)的吸附没有明显影响，但显著降低了 APTES-ATP 上 Cr(III)的吸附。共存阳离子通过与 Cr(III)竞争吸附剂表面结合的 EDTA 基团，导致 EDTA-ATP 上 Cr(III)的吸附减少。Cr(III)在 EDTA-ATP 上的吸附等温线符合 Langmuir 模型，在 25°C 和 pH 3.0 下，该吸附剂对 Cr(III)的最大吸附容量为 131.37mg/g。Cr(Ш)负载的吸附剂可在 HCl 溶液中容易再生，并且再生的吸附剂仍对 Cr(III)具有高吸附容量。XPS 分析证实，EDTA-ATP 上 Cr(III)吸附增强归因于 Cr(III)与吸附剂表面结合的羧基和氨基之间形成稳定的配合物。
