Insight into mechanisms of fluoride removal from contaminated groundwater using lanthanum-modified bone waste
Insight into mechanisms of fluoride removal from contaminated groundwater using lanthanum-modified bone waste
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DOI：
10.1039/c7ra10713g
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发表时间：
2017-11
期刊：
影响因子：
3.9
通讯作者：
Lanting Wang;Yanhua Xie;Yang Jinglong;Xueqiang Zhu;Qili Hu;Xiaoyun Li;Zhuang Liu
中科院分区：
文献类型：
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作者：
Lanting Wang;Yanhua Xie;Yang Jinglong;Xueqiang Zhu;Qili Hu;Xiaoyun Li;Zhuang Liu
目前全球地下水中的氟污染问题已导致对高效吸附剂的需求增加。与此同时，骨料的丢弃和填埋也造成了环境污染。为了实现废骨料的资源化利用，提高除氟效率，合成了一种镧改性废骨料复合材料，并对其进行了除氟试验。用扫描电子显微镜、比表面积、X射线衍射仪、红外光谱和X射线光电子能谱对其进行了表征。通过批量实验评价了其对氟的吸附性能。扫描电子显微镜和比表面积分析表明，La的引入改变了吸附剂的孔结构，提高了其比表面积。LBW复合材料的pH值为11.4，在较宽的pH范围(2.5-10.0)内，溶液的pH值对氟的吸附几乎没有影响。常见共存氧阴离子在0~100mgL−-1范围内对测定结果无显著影响。氟的吸附是典型的化学吸附过程，符合粒子群算法和F-L粒子群优化方程。Fver模型能更准确地预测氟吸附初期的平衡表面复盖度较大。等温线研究表明，该反应符合朗缪尔模型，表明该过程为单分子层吸附。提出了可能的除氟和再生方法。氟的吸附主要受LBW表面带正电荷的静电吸引和氟与氢氧化物离子之间的离子交换过程控制。本研究为实际应用中去除受污染地下水中的氟提供了一种替代方法。
The current worldwide issue of fluoride contamination in groundwater has resulted in an increased demand for efficient adsorbents. Meanwhile discard and landfill of bone waste has led to environmental pollution. In order to achieve bone waste recycling and enhance the efficiency of fluoride removal, a lanthanum-modified bone waste (LBW) composite was synthesized and tested to remove fluoride from contaminated groundwater. The adsorbent characterization was conducted by SEM, BET, XRD, FTIR and XPS. The fluoride adsorption performance was evaluated by batch experiments. SEM and BET revealed that the introduction of lanthanum could modify the porous structure of the adsorbent and enhance its specific surface area. The LBW composite had a high pHzpc of 11.4 and the fluoride adsorption was barely affected by the solution pH over a wide pH range of 2.5–10.0. The influence of common co-existing oxygen anions in the range of 0–100 mg L−1 was not significant. The fluoride adsorption was a typical chemisorption process and followed PSO and F-L PSO equations. The FVER model provided a more accurate prediction of a larger surface coverage degree with respect to equilibrium at the initial stage during adsorption of fluoride. Isotherm studies revealed that the reaction obeyed the Langmuir model, indicating that this process was monolayer adsorption. Possible defluoridation and regeneration were proposed. The fluoride adsorption was mainly controlled by the processes of electrostatic attraction on the LBW surface with a positive charge and ion exchange between fluoride and hydroxide ions. This research provides an alternative method for fluoride removal from contaminated groundwater in practical applications.