The strongly acidic wastewater containing fluoride [F(-I)] is generally neutralized using lime, producing massive hazardous solid waste, which may present serious environmental risks. In this study, a novel precipitant, N,N'-Bis(3-(triethoxysilyl)propyl)thiourea, was developed for the selective removal of F(-I) from strongly acidic wastewater. The precipitant was synthesized using (3-aminopropyl)triethoxysilane and thiourea at a molar ratio of 2:1 under 160 ℃. More than 90% of initial F(-I) was removed by the prepared precipitant from strong acidic wastewater produced by nonferrous metal smelting industry, and the residual F(-I) concentration decreased to below 100 mg/L. The F(-I) removal performance is almost free from the interference of coexisting ions. Only 6 kg/m³ of fluoride slag, which can be recycled as a concrete waterproofing agent, was produced. The F(-I) removal mechanism including substitution, polycondensation, ion exchange and complexation was clarified: -OH on Si atoms in the hydrolysis product of BTPT was substituted by F(-I), and a fluoro-substituted product formed; the polycondensation of BTPT and fluoro-substituted product produced polymer precipitates; the specific adsorption of F(-I) on the polymer precipitates occurred through ion exchange with -OH and complexation with -NH₂⁺-.

含有氟化物[F（-I）]的强酸性废水通常使用石灰中和，产生大量的危险固体废物，这可能会带来严重的环境风险。在这项研究中，开发了一种新型沉淀剂N，N'-双（3-（三乙氧基甲硅烷基）丙基）硫脲，用于从强酸性废水中选择性去除F（-I）。在160℃下，摩尔比为2：1的（3-氨基丙基）三乙氧基硅烷和硫脲合成了沉淀剂。所制备的沉淀剂从有色金属冶炼行业产生的强酸性废水中去除了超过90％的初始F（-I），残留F（-I）浓度降至100 mg / L以下。F（-I）去除性能几乎不受共存离子的干扰。仅6 kg / m ³制成了可作为混凝土防水剂回收的氟化物渣。阐明了包括取代，缩聚，离子交换和络合的F（-I）去除机理：BTPT水解产物中Si原子上的-OH被F（-I）取代，形成氟取代产物；BTPT和氟代产物的缩聚反应产生了聚合物沉淀; F（-I）在聚合物沉淀上的特异性吸附是通过与-OH进行离子交换并与-NH ₂ ⁺ -络合而发生的。