Separation and Recycling of Functional Nanoparticles Using Reversible Boronate Ester and Boroxine Bonds
Separation and Recycling of Functional Nanoparticles Using Reversible Boronate Ester and Boroxine Bonds
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DOI：
10.1021/acs.iecr.9b00253
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发表时间：
2019-03-20
影响因子：
4.2
通讯作者：
Ye, Lei
中科院分区：
文献类型：
--
作者：
Liu, Chen;Gong, Haiyue;Ye, Lei
可持续和绿色化学理念要求有效分离和回收有价值的功能纳米颗粒。在这项工作中，建立了一种无需重型仪器即可分离和回收合成纳米颗粒的可行方法。通过使用硼酸官能化纳米颗粒与聚（乙烯醇）之间以及纳米颗粒本身之间形成的可逆硼酸酯和环硼氧烷键，实现了纳米颗粒的分离。可逆共价键通过简单调节溶剂pH值来控制。为了证明该方法的可行性，使用两种类型的纳米颗粒（无机二氧化硅纳米颗粒和表面用硼酸功能化的有机分子印迹纳米颗粒）作为模型。添加聚乙烯醇并调节至碱性 pH 值后，纳米颗粒形成聚集体并容易从溶液中沉降。更换为酸性溶剂后，硼酸功能化纳米颗粒和聚（乙烯醇）之间形成的硼酸酯键被水解，聚（乙烯醇）从纳米颗粒聚集体中释放出来。由于新的颗粒间环硼氧烷键的形成，颗粒保持为聚集体。通过使用 pH 控制的动态颗粒聚集，普萘洛尔印迹纳米颗粒可以轻松回收并重复使用，无需离心。这项工作为潜在的大规模工业应用提供了一种回收有价值的功能纳米材料的新方法。
The sustainable and green chemistry concept calls for effective separation and recycling of valuable functional nanoparticles. In this work, a viable approach to separate and recover synthetic nanoparticles without involving heavy-duty instruments was established. The nanoparticle separation was enabled by using reversible boronate ester and boroxine bonds formed between boronic acid-functionalized nanoparticles and poly(vinyl alcohol) and between the nanoparticles themselves. The reversible covalent bonds were controlled by simple adjustment of solvent pH. To demonstrate the viability of the approach, two types of nanoparticles-inorganic silica nanoparticles and organic molecularly imprinted nanoparticles functionalized with boronic acid on their surface-were used as models. Upon addition of poly(vinyl alcohol) and adjustment to basic pH, the nanoparticles formed aggregates and readily settled from solution. After changing to an acidic solvent, the boronate ester bonds formed between boronic acid-functionalized nanoparticles and poly(vinyl alcohol) were hydrolyzed, and poly(vinyl alcohol) was released from the nanoparticle aggregates. The particles remained as aggregates due to the formation of new, interparticle boroxine bonds. By use of pH-controlled dynamic particle aggregation, propranolol-imprinted nanoparticles could be easily recovered and used repetitively without centrifugation. This work provides a new approach for recovery of valuable functional nanomaterials for potentially large-scale industrial applications.