Ionic Dendrimer Based Polyamide Membranes for Ion Separation

Abstract

Separating low/high-valent ions with sub-nanometer sizes is a crucial yet challenging task in various areas (e.g., within environmental, healthcare, chemical, and energy engineering). Satisfying high separation precision requires membranes with exceptionally high selectivity. One way to realize this is constructing well-designed ion-selective nanochannels in pressure-driven membranes where the separation mechanism relies on combined steric, dielectric exclusion, and Donnan effects. To this aim, charged nanochannels in polyamide (PA) membranes are created by incorporating ionic polyamidoamine (PAMAM) dendrimers via interfacial polymerization. Both sub-10 nm sizes of the ionic PAMAM dendrimer molecules and their gradient distributions in the PA nanofilms contribute to the successful formation of defect-free PA nanofilms, containing both internal (intramolecular voids) and external (interfacial voids between the ionic PAMAM dendrimers and the PA matrix) nanochannels for fast transport of water molecules. The external nanochannels with tunable ionizable groups endow the PA membranes with both high low/high-valent co-ion selectivity and chemical cleaning tolerance, while the ion sieving/transport mechanism was analyzed by employing the Donnan steric pore model with dielectric exclusion.

Toward Enhancing Desalination and Heavy Metal Removal of TFC Nanofiltration Membranes: A Cost-Effective Interface Temperature-Regulated Interfacial Polymerization

“…Obviously, the surface membrane pores of the substrate became invisible for all of the NF membranes (Figure ), proving that the IP reaction had been successfully carried out and the newly generated PA layer covered the original pores. For TFCM@–15, a very smooth surface was obtained (Figure a), which was totally different from the rough surface features of typical NF membranes fabricated at room temperature . It is widely accepted that the rough surface of the TFC membranes is greatly linked to the interface heat-induced nanobubble releasing during the IP reaction .…”

“…For TFCM@−15, a very smooth surface was obtained (Figure 2a), which was totally different from the rough surface features of typical NF membranes fabricated at room temperature. 38 It is widely accepted that the rough surface of the TFC membranes is greatly linked to the interface heat-induced nanobubble releasing during the IP reaction. 39 Cooling the organic solution could effectively neutralize the heat generated by IP, thus inhibiting the release of the nanobubbles existing in the aqueous solution.…”

Angstrom-scale ion channels towards single-ion selectivity

“…Li + ions selectively permeate through the membrane from multi-metal ions mixed feed solution to permeate solution, leading to a Li + permeation rate up to 0.08 mol m À2 h À1 , and the selectivities of Li + /K + , Li + /Na + , and Li + /Mg 2+ are 12.7, 15.5, and 28, respectively. In other instances, membranes with high water flux and ion selectivity [249][250][251] have enabled simultaneous water treatment and ion recovery by integrating the ion-selective membranes with a forward osmosis system.…”

Application of Dendrimers in Anticancer Diagnostics and Therapy

“…The synthesis of dendrimers makes it possible to control each stage of generation, resulting in a strictly defined structure [ 8 ]. There are various types of dendrimers, including phosphorus (P-dendrimers) [ 9 ], polyamidoamines (PAMAM) [ 10 ], polyamines [ 11 ], polyamides [ 12 ], polypeptides [ 13 ], polyesters [ 14 ], carbosilicates (CBS) [ 15 ], poly(L-lysine) dendrimers (PLL) [ 16 ], polyesters (PGLSA-OH) [ 17 ], poly (2,2) acid dendrimers -bis (hydroxymethyl) propionic (bis-MPA) [ 18 ], and peptide dendrimers [ 19 ]. In addition, we also distinguish dendrimers based on sugar units and oligonucleotides.…”