†Graduate School of EEWS (Energy, Environment, Water and Sustainability), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
‡Department of Applied Chemistry, University of Johannesburg Johannesburg, Republic of South Africa.
Environ Sci Technol. 2015 Aug 18;49(16):9431-42. doi: 10.1021/acs.est.5b01594. Epub 2015 Aug 10.
Advances in industrial ecology, desalination, and resource recovery have established that industrial wastewater, seawater, and brines are important and largely untapped sources of critical metals and elements. A Grand Challenge in metal recovery from industrial wastewater is to design and synthesize high capacity, recyclable and robust chelating ligands with tunable metal ion selectivity that can be efficiently processed into low-energy separation materials and modules. In our efforts to develop high capacity chelating membranes for metal recovery from impaired water, we report a one-pot method for the preparation of a new family of mixed matrix polyvinylidene fluoride (PVDF) membranes with in situ synthesized poly(amidoamine) [PAMAM] particles. The key feature of our new membrane preparation method is the in situ synthesis of PAMAM dendrimer-like particles in the dope solutions prior to membrane casting using low-generation dendrimers (G0 and G1-NH2) with terminal primary amine groups as precursors and epichlorohydrin (ECH) as cross-linker. By using a combined thermally induced phase separation (TIPS) and nonsolvent induced phase separation (NIPS) casting process, we successfully prepared a new family of asymmetric PVDF ultrafiltration membranes with (i) neutral and hydrophilic surface layers of average pore diameters of 22-45 nm, (ii) high loadings (∼48 wt %) of dendrimer-like PAMAM particles with average diameters of ∼1.3-2.4 μm, and (iii) matrices with sponge-like microstructures characteristics of membranes with strong mechanical integrity. Preliminary experiments show that these new mixed matrix PVDF membranes can serve as high capacity sorbents for Cu(II) recovery from aqueous solutions by ultrafiltration.
工业生态学、海水淡化和资源回收方面的进展表明，工业废水、海水和卤水是重要的、尚未充分开发的关键金属和元素来源。从工业废水中回收金属的一个重大挑战是设计和合成具有高容量、可回收和稳健的螯合配体，其金属离子选择性可调，可高效地加工成低能耗的分离材料和模块。在我们努力开发用于从受污染水中回收金属的高容量螯合膜的过程中，我们报告了一种用于制备新型混合基质聚偏二氟乙烯（PVDF）膜的一锅法，该膜具有原位合成的聚（酰胺-胺）[PAMAM]颗粒。我们新的膜制备方法的关键特点是，在使用末端伯胺基团作为前体和表氯醇（ECH）作为交联剂的低代树突状分子（G0 和 G1-NH2）在铸膜液中原位合成 PAMAM 树突状颗粒。通过采用热诱导相分离（TIPS）和非溶剂诱导相分离（NIPS）相结合的铸膜工艺，我们成功地制备了具有以下特征的新型不对称 PVDF 超滤膜：（i）具有 22-45nm 平均孔径的中性和亲水性表面层；（ii）负载量高（约 48wt%）的具有 1.3-2.4μm 平均直径的树突状 PAMAM 颗粒；（iii）具有海绵状微观结构的基质，这些结构是具有强机械完整性的膜的特征。初步实验表明，这些新型混合基质 PVDF 膜可用作通过超滤从水溶液中回收 Cu(II)的高容量吸附剂。
