Rational Design of High-Performance Cationic Organic Network Adsorbents

Abstract

Development of high-performance ionic organic network (ION) adsorbents is of great importance for water remediation. However, the research on IONs is still nascent, especially, the design philosophy regarding contaminant adsorption has rarely been explored. In this contribution, we optimized the adsorption efficiency of IONs by increasing the density of charged sites and improving their accessibility. We first produced a new cationic organic network (CON), CON-LDU4, with a high density of positive sites via synthesis from tetra­(4-pyridyl)­ethene. Compared to the analogue CON-LDU2 that synthesized from tetra­(4-(4-pyridyl)­phenyl)­ethene, CON-LDU4 exhibited higher efficiency in adsorption of methyl blue, indicating that the higher ionic density results in the higher adsorption efficiency. To further improve the accessibility of the active sites, another new CON material (CON-LDU5) was synthesized by employing a hard template. CON-LDU5 exhibited a larger specific surface area than CON-LDU4, with clearly enhanced adsorption efficiency. Finally, CON-LDU5 was used to capture CrO4 2– ions in water with fast adsorption kinetics (k 2 = 0.0328 g mg–1 min–1) and high adsorption capacity (369 mg g–1).

Triptycene-Based Cationic Porous Organic Polymer for the Swift and Effective Removal of Organic and Inorganic Anionic Water Pollutants

“…The relatively low surface area recorded is due to the presence of bromide counteranions in the pores of TP_iPOP-2. 32 The presence of micro-and mesopores in the skeleton of TP_iPOP-2 is revealed by the pore size distribution of TP_iPOP-2 (Figure S6). Field emission scanning electron microscopy (FE-SEM) data are useful to understand the morphology associated with a given material.…”

“…The BET surface area of TP_iPOP-2 was estimated to be 56 m 2 /g (Figures S4 and S5). The relatively low surface area recorded is due to the presence of bromide counteranions in the pores of TP_iPOP-2 . The presence of micro- and mesopores in the skeleton of TP_iPOP-2 is revealed by the pore size distribution of TP_iPOP-2 (Figure S6).…”

“…In the context of the use of iPOPs for water purification, it is anticipated that a cationic porous organic polymer (cPOP) will be most effective for the efficient capture of harmful anionic contaminants present in polluted water via a facile anion-exchange process. A literature survey indicated that only a handful of examples of cPOP have been reported to date and their use as adsorbents for the removal of toxic anions dissolved in aqueous solutions is largely underrepresented in the scientific literature. − …”

Porous organic polymers (POPs) for environmental remediation

“…303,304 In this regard, due to its affordability, simplicity of use, and ability to produce less harmful secondary species, POP-based adsorption (by chelation or ion-exchange) of these toxic oxoanions from wastewater has attracted increasing interest. 138,168,[305][306][307] In some cases, it is also found to be superior to other porous materials towards decontamination application. A few representative examples of POP based oxoanion capture studies are discussed below.…”

Tuning inter‐wall spacing and structural properties of double‐walled gallium arsenide nanotubes

“…GaAsNTs are considered as suitable options instead of carbon nanotubes [2, 3, 5]. GaAs are good materials for optoelectronic and electronic usages [15–17]. In addition, these nanotubes are more suitable for specific applications in mechanical and electronic devices than carbon nanotubes.…”