Complex multiphase waste metalworking emulsions, which contain large amounts of surfactants and mineral oil, are difficult to treat efficiently by traditional molecular demulsifiers. We synthesized one type of functionalized magnetic nanoparticles grafted with amino groups ([email protected]₂) to treat waste metalworking emulsions from different mechanical processing factories and investigated the demulsification mechanism. The [email protected]₂ showed an excellent demulsification performance, achieving 85–97% chemical oxygen demand (COD) removal for most of the waste metalworking emulsions. The results indicated the advantage of the three-step demulsification process (adsorption of [email protected]₂ on droplets, droplet coalescence, and the magnetic transfer of droplets in the magnetic field) over traditional two-step demulsification (adsorption of MNPs on droplets and the transfer of droplets in the magnetic field). In addition, electrostatic interactions between [email protected]₂ and surfactants were confirmed as the driving force of demulsification. Isothermal titration calorimeter quantified the interactions at the molecular level; the enthalpy was 1.83 kJ/mol, affinity coefficient between [email protected]₂ and the surfactant was 1.5 × 10³, and the stoichiometric number of the surfactant and [email protected]₂ was 11.5. This research provides a new perspective for the treatment of waste metalworking emulsions.

中文翻译：

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可循环利用的功能性磁性纳米粒子，用于静电相互作用驱动的废金属加工乳液的快速破乳

含有大量表面活性剂和矿物油的复杂的多相废金属加工乳液很难用传统的分子破乳剂有效地处理。我们合成了一种类型的功能化磁性纳米粒子，其接枝有氨基（[email protected] ₂）以处理来自不同机械加工工厂的废金属加工乳液，并研究了破乳机理。受[电子邮件保护] ₂具有出色的破乳性能，对于大多数废金属加工乳液，化学需氧量（COD）去除率达到85-97％。结果表明了三步破乳过程的优势（吸附[受电子邮件保护] ₂传统的两步破乳法（MNP在液滴上的吸附和液滴在磁场中的转移）上的分离，液滴的聚结，液滴在磁场中的磁转移）。另外，[电子邮件保护的] ₂和表面活性剂之间的静电相互作用被确认为破乳的驱动力。等温滴定热量计在分子水平上定量了相互作用。焓为1.83kJ / mol，[受电子邮件保护的] ₂与表面活性剂之间的亲和系数为1.5×10 ³，表面活性剂与[受电子邮件保护的] ₂的化学计量数为11.5。该研究为废金属加工乳液的处理提供了新的视角。