Key flocculated-species is the pivotal factor influencing the effectiveness of flocculants, which in turn directly determines the performance of mainstream wastewater treatment processes. Recovery of titanium-coagulated sludge and high-efficiency of titanium-coagulation have made titanium-coagulants an attractive hot point. However, the separation of key titanium-based flocculated-species remains a critical bottleneck limiting the advancement of titanium-based flocculant chemistry in water treatment. This study developed an efficient method for separating the key flocculated-species, named the sulfate precipitation method, which enables the effective purification of the key titanium-based flocculated-species. The electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) results demonstrated the successful separation of medium and large titanium-hydrolyzed-species. Ti-Ferron synchronous analysis was employed to indicate the separation of hydrolyzed products with different degrees of polymerization, including large, medium, and small species. The distribution of [OH-]/[Ti4+] (basicity) molar ratios was verified to confirm the reorganization of hydrolysis products after the reaction, resulting in varied basicities. Zeta potential results showed that species rich in medium and large hydrolyzed products had fewer positive charges, which was likely attributed to their superior flocculation efficiency, possibly due to sweep flocculation. The inductively coupled plasma mass spectrometry (ICP-MS) indicated that sulfur was present in the separated products. It was speculated that, on the one hand, the introduction of sulfate ions might have directly participated in the re-polymerization of titanium-hydrolyzed-species, potentially resulting in sulfate-doped titanium-based hydrolysis products. On the other hand, sulfate ions might have been involved in a substitution reaction with Cl- at active sites. Co-existence of these two pathways was deemed highly probable. The removal efficiency of organic matter was improved by approximately 20%, possibly owing to the rough surface (Ra = 16.2 nm). Additionally, larger flocs were generated, significantly shortening the sedimentation time in practical applications. This research presents a strategy for isolating key Ti-based flocculated species and establishes a base for their practical application.

中文翻译：

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从钛基絮凝剂中分离关键絮凝物质的硫酸盐沉淀法的开发和评价


关键的絮凝物质是影响絮凝剂有效性的关键因素，而絮凝剂又直接决定了主流废水处理工艺的性能。钛凝固污泥的回收和钛凝结的高效使钛凝结剂成为一个有吸引力的热点。然而，关键钛基絮凝物质的分离仍然是限制钛基絮凝剂化学在水处理中发展的关键瓶颈。本研究开发了一种分离关键絮凝物质的有效方法，称为硫酸盐沉淀法，该方法能够有效纯化关键的钛基絮凝物质。电喷雾电离飞行时间质谱 （ESI-TOF-MS） 结果表明，中大型钛水解物质的成功分离。采用 Ti-Ferron 同步分析来指示具有不同聚合度的水解产物的分离，包括大、中和小物种。验证了 [OH-]/[Ti4+]（碱度）摩尔比的分布，以确认反应后水解产物的重组，从而产生不同的碱度。Zeta 电位结果表明，富含中大型水解产物的物质具有较少的正电荷，这可能归因于它们卓越的絮凝效率，可能是由于扫掠絮凝。电感耦合等离子体质谱 （ICP-MS） 表明分离产物中存在硫。 据推测，一方面，硫酸根离子的引入可能直接参与了钛水解物质的再聚合，从而可能产生硫酸盐掺杂的钛基水解产物。另一方面，硫酸根离子可能参与了活性位点与 Cl- 的取代反应。这两种途径共存被认为是极有可能的。有机物的去除效率提高了约 20%，这可能是由于表面粗糙 （Ra = 16.2 nm）。此外，还产生了更大的絮凝体，大大缩短了实际应用中的沉降时间。本研究提出了一种分离关键 Ti 基絮凝物质的策略，并为其实际应用奠定了基础。