Feng Shuyue, Zhang Wenjuan, Che Jianyong, Wang Chengyan, Chen Yongqiang
State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China.
State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China; School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Sci Total Environ. 2024 Nov 15;951:175507. doi: 10.1016/j.scitotenv.2024.175507. Epub 2024 Aug 13.
Industrial wastewater containing high levels of fluoride and phosphate poses significant environmental challenges and results in the waste of non-renewable resources. This study investigates the use of La(OH) as a precipitating agent to selectively remove and separate fluoride from phosphate in such wastewater. The findings indicate that fluoride removal efficiency is highly dependent on the pH level and La(OH) dosage. Using Response Surface Methodology, the optimal conditions for fluoride precipitation were identified as a pH range of 1.0 to 2.5, a reaction time of 60-80 min, a La/3F molar ratio of 2.0, and reaction temperature of 25 °C. Under these parameters, the fluoride removal efficiency exceeded 96.9 %, while phosphate removal remained around 7.2 %. Further Density Functional Theory calculations and characterization confirmed La(OH) has a strong affinity for fluoride than phosphate under acidic conditions, leading to the formation of a LaF precipitate without forming LaPO, effectively separating fluoride from phosphate. These results demonstrate an efficient strategy for treating wastewater with high fluoride and phosphate content, enabling the selective precipitation and recovery of these elements for sustainable management.
含有高浓度氟化物和磷酸盐的工业废水对环境构成了重大挑战，并导致不可再生资源的浪费。本研究探讨了使用氢氧化镧作为沉淀剂，以选择性地从这类废水中去除和分离氟化物与磷酸盐。研究结果表明，氟化物去除效率高度依赖于pH值和氢氧化镧用量。采用响应面法，确定了氟化物沉淀的最佳条件为pH范围1.0至2.5、反应时间60 - 80分钟、镧与氟的摩尔比为2.0以及反应温度25℃。在这些参数下，氟化物去除效率超过96.9%，而磷酸盐去除率约为7.2%。进一步的密度泛函理论计算和表征证实，在酸性条件下，氢氧化镧对氟化物的亲和力比对磷酸盐强，导致形成氟化镧沉淀而不形成磷酸镧，从而有效地将氟化物与磷酸盐分离。这些结果展示了一种处理高氟和高磷含量废水的有效策略，能够实现这些元素的选择性沉淀和回收，以进行可持续管理。
