Gong Huichun, Ke Pingchao, Zhou Yipeng, Xu Lingling, He Guang, Jian Peng
School of Water Resources and Environmental Engineering, East China University of Technology, Nanchang, 330013, Jiangxi, People's Republic of China.
State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, 330013, Jiangxi, People's Republic of China.
Environ Geochem Health. 2024 Dec 18;47(1):21. doi: 10.1007/s10653-024-02331-6.
Fluoride contamination is a serious environmental problem in lepidolite hydrometallurgy wastewater. The treatment of fluoride-bearing wastewater is challenging because of the presence of coexisting ions including lithium (Li), rubidium (Rb), silicate (SiO), sulfate radical (SO). However, aluminum-modified zeolite (Al@zeolite) with sufficient hydroxyl groups and high adaptability has unique advantages for eliminating fluoride from lepidolite hydrometallurgy wastewater. Al@zeolite was prepared on natural zeolite by an atmospheric process and then used for the adsorption of fluorine from fluoride-bearing wastewater produced by the lepidolite hydrometallurgy process. The results of material characterization confirmed the successful immobilization of aluminum within the zeolite pores and indicated the formation of zeolite-Al-OH. The zeolite host significantly enhanced the chemical stability of Al@zeolite against pH changes for a wide pH range of 2.0-10.0. The adsorbent had a surface area of 33.46 m/g and demonstrated excellent capacity and selectivity for fluoride adsorption. Notably, a maximum adsorption of 98.6% was observed at a pH value of 6.0 for a duration of 20 min with a fluoride content of 20 mg/L, and the equilibrium concentration decreased to 0.4 mg/L. The results of fluorine adsorption showed that fluoride uptake onto Al@zeolite agreed well with the pseudo-second-order kinetic model and the Langmuir isotherm model. The reusability of the substance was evaluated for up to eight cycles following consecutive regeneration with 0.2 mol/L AlCl. The exhausted Al@zeolite was effectively regenerated through simple alkaline treatment for recycling. The above results verified that Al@zeolite is a new kind of efficient defluoridation adsorbent for lepidolite hydrometallurgy wastewater with practical application prospects.
在锂云母湿法冶金废水中，氟化物污染是一个严重的环境问题。由于存在包括锂（Li）、铷（Rb）、硅酸盐（SiO）、硫酸根（SO）在内的共存离子，含氟废水的处理具有挑战性。然而，具有足够羟基和高适应性的铝改性沸石（Al@沸石）在去除锂云母湿法冶金废水中的氟方面具有独特优势。通过常压法在天然沸石上制备了Al@沸石，然后将其用于吸附锂云母湿法冶金过程产生的含氟废水中的氟。材料表征结果证实了铝成功固定在沸石孔内，并表明形成了沸石 - Al - OH。在2.0 - 10.0的宽pH范围内，沸石主体显著提高了Al@沸石对pH变化的化学稳定性。该吸附剂的表面积为33.46 m²/g，对氟吸附表现出优异的容量和选择性。值得注意的是，在pH值为6.0、吸附20分钟、氟含量为20 mg/L的情况下，最大吸附率达到98.6%，平衡浓度降至0.4 mg/L。氟吸附结果表明，Al@沸石对氟的吸附符合准二级动力学模型和朗缪尔等温线模型。用0.2 mol/L AlCl连续再生后，对该物质的可重复使用性进行了多达八个循环的评估。通过简单的碱处理可有效再生耗尽的Al@沸石以进行循环利用。上述结果证实，Al@沸石是一种新型高效的锂云母湿法冶金废水除氟吸附剂，具有实际应用前景。
