物理化学学报

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由单层薄水铝石制备的活性氧化铝处理水中氟离子

孙建川1, 王旭辉1, 陈帅奇1, 廖艳清1, 郜阿旺1, 胡雨昊1, 杨涛1, 徐向宇1, 王颖霞2, 宋家庆1   

  1. 1 北京化工大学, 化工资源有效利用国家重点实验室, 北京 100029;
    2 北京大学化学与分子工程学院无机化学研究所, 北京 100871
  • 收稿日期:2019-11-05 修回日期:2019-12-13 录用日期:2019-12-14 发布日期:2019-12-20
  • 通讯作者: 宋家庆 E-mail:songjq@126.com
  • 基金资助:
    华东师范大学上海绿色化学与化学过程重点实验室(H2016107)资助项目

Defluoridation of Water Using Active Alumina Derived from Single-Layer Boehmite

Jianchuan Sun1, Xuhui Wang1, Shuaiqi Chen1, Yanqing Liao1, Awang Gao1, Yuhao Hu1, Tao Yang1, Xiangyu Xu1, Yingxia Wang2, Jiaqing Song1   

  1. 1 State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China;
    2 Institute of Inorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
  • Received:2019-11-05 Revised:2019-12-13 Accepted:2019-12-14 Published:2019-12-20
  • Supported by:
    The project was supported by the Shanghai Key Laboratory of Green Chemistry and Chemical Processes, East China Normal University, China (H2016107).

摘要: 合成高效低成本的氟离子吸附剂仍是具有挑战的研究课题。本文采用无有机物的方法制备了单层结构的薄水铝石,并以此薄水铝石得到大比表面积的活性氧化铝。活性氧化铝的大比表面积保证了很高的吸附效率,合成过程无有机表面活性剂或模板剂的使用,控制了成本。采用X射线衍射(XRD)及扫面电镜(SEM)等方法对样品进行了表征,发现制备的氧化铝前体为单层结构的薄水铝石,其比表面积为789.4 m2·g-1,焙烧后得到活性氧化铝的比表面积为678.4 m2·g-1,孔体积为3.20 cm3·g-1。并系统研究了吸附剂用量、吸附时间等因素对活性氧化铝吸附水中氟离子的影响。研究结果表明,本文制备活性氧化铝对水中氟离子的吸附量可达67.6 mg·g-1。仅分别需0.6、1.0或2.6 g·L-1活性氧化铝就可将10、20或50 mg·L-1的氟离子溶液处理至中国饮用水标准(1.0 mg·L-1)以下。并且此活性氧化铝在pH=4–9的范围内均可用于水中氟离子的处理,对吸附有较大影响的共存离子为SO42-及PO43-,进一步研究表明,活性氧化铝对氟离子的吸附遵循准二级模型和朗格缪尔等温模型。

关键词: 除氟, 活性氧化铝, 单层, 大比表面积, 吸附, 高吸附量, 无有机物

Abstract: The preparation of high-efficiency and low-cost adsorbents for the defluoridation of drinking water remains a huge challenge. In this study, single-layer and multi-layer boehmite were first synthesized via an organicfree method, and active alumina used for fluoride removal from water was obtained from the boehmite. The advantage of a single layer is that more aluminum is exposed to the surface, which can provide more adsorption sites for fluoride. The active alumina adsorbent derived from single-layer boehmite exhibits a high specific surface area and excellent adsorption capacity. The high surface area ensures a high adsorption capacity, and the organic-free synthesis method lowers the preparation cost. The asprepared adsorbent was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FTIR) and nitrogen adsorption-desorption analysis. The single-layer structure of boehmite was determined from the simulated XRD diffraction pattern of single-layer boehmite. The disappearance of the (020) diffraction peak of boehmite illustrates that the dimensions in the b direction are extremely small, and according to the XRD simulation results, the single-layer structure of boehmite could be determined. Single-layer boehmite with a surface area of 789.4 m2·g-1 was formed first. The active alumina obtained from the boehmite had a surface area of 678.4 m2·g-1, and the pore volume was 3.20 cm3·g-1. The fluoride adsorption of the active alumina was systematically studied as a function of the adsorbent dosage, contact time, concentration, co-existing anions, and pH. The fluoride adsorption capacity of the active alumina obtained from the single-layer boehmite reached up to 67.6 mg·g-1, which is higher than those of most alumina adsorbents reported in the literature. The adsorption capacities of the active alumina are related to the specific surface area and the number of hydroxyl groups on the surface. Dosages of 0.6, 1.0, and 2.6 g·L-1 of active alumina were able to lower the 10, 20, and 50 mg·L-1 fluoride solutions, respectively, below the maximum permissible limit of fluoride in drinking water in China (1.0 mg·L-1), suggesting that the active alumina synthesized in this work is a promising adsorbent for defluoridation of drinking water. In addition, the fluoride adsorption is applicable in a wide pH range from 4 to 9 and is mainly interfered by SO42- and PO43-. Further investigation suggested that the fluoride adsorption of the active alumina follows the pseudo second-order model and Langmuir isotherm model.

Key words: Defluoridation, Active alumina, Single layer, High surface area, Adsorption, High adsorption capacity, Organic-free

MSC2000: 

  • O647