A novel understanding of residual nano-Al-13 formation and degradation during coagulation and flocculation: a proof based on ESI-TOF-MS
A novel understanding of residual nano-Al-13 formation and degradation during coagulation and flocculation: a proof based on ESI-TOF-MS
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对混凝和絮凝过程中残留纳米 Al-13 形成和降解的新认识：基于 ESI-TOF-MS 的证明
DOI：
10.1039/c8en00921j
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发表时间：
2018
影响因子：
7.3
通讯作者：
Feng Chenghong
中科院分区：
文献类型：
--
作者：
Tian Chenhao;Wu Yuehan;Wei Mingzhi;Feng Chenghong
纳米Al 13团簇有可能在混凝过程中形成和保留，但不能通过传统的仪器技术在真实的时间内直接追踪，因为在投加后仅存在痕量浓度。在这项研究中，首次引入了优化的电喷雾电离质谱（ESI-MS）方法，以确定使用AlCl 3（单体Al，即，Alm）和聚合氯化铝（PAC 1）作为混凝剂。通过统计分析和实时跟踪实验，阐明了Alm、Alo、Al 13和Alts等Al团簇的转变机制.在以AlCl 3为混凝剂进行的混凝批实验中，可以检测到纳米Al 13团簇。此外，使用统计方法，在PAC混凝剂中的Al 13团簇和由AlCl 3混凝形成的Al 13团簇被证实是有效的混凝剂物种。在实时跟踪实验中，添加凝聚剂后立即观察到Alm、Alo、Al 13和Alts簇之间的可逆转化（即，在凝固过程中）。在随后的过程中（即，絮凝过程），仅发生絮体聚集，四种类型的Al团簇之间没有明显的转化。絮凝体的不断聚集和增加主要归因于颗粒与Al团簇的聚并。矿物-水界面被推断为有利于Alm和Alo聚集体转化为Al 13以及逆反应（例如，Al 13的降解）。
Nano-Al13 clusters have the potential to form and remain in a coagulation process, but cannot be directly traced by traditional instrumental techniques in real time since there is only a trace concentration after being dosed. In this study, an optimized electrospray ionization mass spectrometry (ESI-MS) method was introduced for the first time to determine the coagulation pathways when using AlCl3 (monomeric Al, i.e., Alm) and polymeric aluminum chloride (PACl) as coagulants. The transformation mechanisms of Al clusters, including Alm, oligomeric Al (Alo), Al13 and transient Al (Alts), were clearly elucidated using statistical analysis and a real-time tracking experiment. The nano-Al13 clusters could be detected in the coagulation batch experiment conducted using AlCl3 as the coagulant. Moreover, using a statistical method, the Al13 clusters in the PACl coagulant and the Al13 clusters formed by AlCl3 coagulation were confirmed to be an efficient coagulant species. In the real-time tracking experiments, the reversible transformations among Alm, Alo, Al13 and Alts clusters were instantly observed after the addition of the coagulant (i.e., during the coagulation process). In the subsequent process (i.e., the flocculation process), only floc aggregation occurred, and no obvious transformations among the four types of Al clusters were observed. The continuous aggregation and increase in floc were mainly attributed to particle coalescence with the Al clusters. The mineral–water interface was inferred to favor the transformation of Alm and Alo aggregates into Al13 as well as the reverse reaction (e.g., the degradation of Al13).