β-Cyclodextrin Polymers on Microcrystalline Cellulose as a Granular Media for Organic Micropollutant Removal from Water
β-Cyclodextrin Polymers on Microcrystalline Cellulose as a Granular Media for Organic Micropollutant Removal from Water
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DOI：
10.1021/acsami.8b22100
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发表时间：
2019-02-27
影响因子：
9.5
通讯作者：
Dichtel, William R.
中科院分区：
文献类型：
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作者：
Alzate-Sanchez, Diego M.;Ling, Yuhan;Dichtel, William R.
被称为微污染物的低浓度有机污染物对水资源的威胁日益严重。在填充床吸附过程中实现能够去除微污染物的新型吸附剂对于快速水净化和其他有效分离是理想的。我们之前开发了基于环糊精的多孔聚合物，在批量实验中证明了对数十种微污染物（MPs）的快速吸收和高亲和力。然而，这些聚合物通常以粉末的形式生产，其颗粒尺寸分布在几十微米的范围内。在这种粉状形式中，环糊精聚合物不能在填充床吸附过程中实现，因为可变粒度会导致孔隙度不足，从而产生高背压。在这里，我们展示了一种简单的方法，通过将环糊精聚合物网络聚合到纤维素微晶体上，以提供核/壳结构，以连续的方式去除水中的微污染物。批量吸附实验表明，该吸附材料对污染物的吸附速度快，对环糊精的可及性高。同样，柱式实验证明了在最小背压下快速吸收模型污染物，证明了在填充床吸附过程中使用的潜力。此外，污染物饱和柱使用甲醇再生和重复使用三次，性能几乎没有变化。用环境相关浓度的15种微污染物混合物进行的柱实验表明，去除是由每种微污染物对环糊精聚合物的亲和力决定的。与环糊精和未修饰的纤维素晶体相比，接枝到纤维素微晶体上的环糊精聚合物更耐厌氧和好氧生物降解，可能是由于芳香交联剂，表现出持久性。总的来说，本研究的结果证明了将新型环糊精吸附剂结合到纤维素基质上的一般策略，可以在填充床吸附过程中快速有效地去除微污染物，以及它们有希望的长期稳定性和再生能力。
Organic contaminants at low concentrations, known as micropollutants, are a growing threat to water resources. Implementing novel adsorbents capable of removing micropollutants during packed-bed adsorption is desirable for rapid water purification and other efficient separations. We previously developed porous polymers based on cyclodextrins that demonstrated rapid uptake and high affinity for dozens of micropollutants (MPs) in batch experiments. However, these polymers are typically produced as powders with irregular particle size distributions in the range of tens of micrometers. In this powdered form, cyclodextrin polymers cannot be implemented in packed-bed adsorption processes because the variable particle sizes yield insufficient porosity packing and consequently generate high back-pressure. Here we demonstrate a facile approach to remove micropollutants from water in a continuous manner by polymerizing cyclodextrin polymer networks onto cellulose microcrystals to provide a core/shell structure. Batch adsorption experiments demonstrate rapid pollutant uptake and high accessibility of the cyclodextrins on the adsorbent. Similarly, column experiments demonstrate rapid uptake of a model pollutant with minimal back-pressure, demonstrating potential for use in packed-bed adsorption processes. Furthermore, the pollutant-saturated columns were regenerated using methanol and reused three times with almost no change in performance. Column experiments conducted with a mixture of 15 micropollutants at environmentally relevant concentrations demonstrated that removal was determined by the affinity of each micropollutant for cyclodextrin polymers. The cyclodextrin polymer grafted onto cellulose microcrystals is more resistant to both anaerobic and aerobic biodegradation as compared to cyclodextrins and unmodified cellulose crystals, presumably due to the aromatic cross-linkers, demonstrating persistence. Collectively, the findings from this study demonstrate a general strategy to incorporate novel cyclodextrin adsorbents onto cellulose substrates to enable rapid and efficient removal of micropollutants during packed-bed adsorption as well as their promising long-term stability and regeneration capabilities.