Organogel-Derived Covalent–Noncovalent Hybrid Polymers as Alkali Metal-Ion Scavengers for Partial Deionization of Water

Abstract

We show that crown ethers (CEs) 1-5 congeal both polar and nonpolar solvents via their self-assembly through weak noncovalent interactions (NCIs) such as CH···O and CH···π interactions. Diisopropylidene-mannitol (6) is a known gelator that self-assembles through stronger OH···O H bonding. These two gelators together also congeal nonpolar solvents via their individual self-assembly. Gelator 6 self-assembles swiftly to fibers, which act as templates and attract CE to their surface through H bonding and thereby facilitate their self-assembly through weak NCI. Polymerization of styrene gels made from CE and 6, followed by the washing off of the sacrificial gelator 6, yields robust porous polystyrene-crown ether hybrid matrices (PCH), having pore-exposed CEs. These PCHs not only were efficient in sequestering alkali metal ions from aqueous solutions but also can be recycled. This novel use of organogels for making solid sorbents for metal-ion scavenging might be of great interest.

Sugar-Based Organogelators for Various Applications

“…Proposal for the preparation of porous metal scavenging hybrid polymer. Reprinted with permission from ref . Copyright 2018 American Chemical Society.…”

“…Exploiting their properties, various applications of physical gels in interdisciplinary areas are being explored. Hydrogels have mainly found applications in biomedical areas such as tissue engineering and drug delivery. , The application of organogels in the field of medicine, , oil-spill recovery, − pesticides, pollutants removal, and supramolecular electronics, − and for developing functional materials such as soft-optics, CO 2 sorbents, conducting cloths, chemical sensors, metal ion scavengers, etc., have been demonstrated. The development of novel gelators, the study of the mechanism of gelation, and the exploration of new applications of gelators are a timely area of research.…”

In2S3‐Polymer Hybrid Gels Derived from In(III) Metal–Organic Gels for Dye Adsorption, Photodegradation, and Bacteria Removal

“…Some researchers have reported the use of functional gels as adsorbents due to their large specific surface area, [34][35][36] and notably, Sureshan and co-workers prepared a kind of hybrid gel as a dyestuff scavenger by gel template synthesis. [37] However, the amount of adsorption is always limited by the efficiency of the adsorbent. On the other hand, photocatalysis is an efficient process for water treatment, and the development of photocatalytic materials has attracted a considerable amount of attention.…”

EDTA-Inspired Polydentate Hydrogels with Exceptionally High Heavy Metal Adsorption Capacity as Reusable Adsorbents for Wastewater Purification

“…Polymeric hydrogels with a three-dimensional cross-linked network structure and appropriate functional groups may be ideal heavy metal ion adsorbents with potential for achieving high binding capacity, mechanical integrity, and reusability. Hydrogels based on a variety of natural and synthetic homopolymers/copolymers, such as chitosan, cellulose, carboxymethyl cellulose (CMC), CMC- grafted -poly­( N -isopropyl acrylamide- co -acrylic acid), crown ether derivative of polystyrene, and poly­(acrylamide- co -4-vinyl pyridine), have been evaluated for scavenging heavy metal ions. These polymeric structures share some common functional groups, including hydroxyl (−OH), thiol (−SH), carboxyl (−COO−), and amines (−NH 2 , −RNH–, and −R 2 N), which are responsible for the binding of heavy metal ions .…”