Monopeptide-Based Powder Gelators for Instant Phase-Selective Gelation of Aprotic Aromatics and for Toxic Dye Removal

Abstract

Through a combinatorial screening of 35 possible phase-selective monopeptide-based organogelators readily made at low cost, we identified five of them with high gelling ability toward aprotic aromatic solvents in the powder form. The best of them (Fmoc-V-6) is able to instantly and phase-selectively gel benzene, toluene, and xylenes in the presence of water at room temperature at a gelator loading of 6% w/v. This enables the gelled aromatics to be separated by filtration and both aromatics and the gelling material to be recycled by distillation. We also identified Fmoc-I-16 as the best gelator for benzyl alcohol, and the corresponding organogel efficiently removes toxic dye molecules by 82−99% from their highly concentrated aqueous solutions. These efficient removals of toxic organic solvents and dyes from water suggest their promising applications in remediating contaminated water resources.

Fabrication of a Nanoporous Silica Hydrogel by Cross-Linking of SiO2–H3BO3–Hexadecyltrimethoxysilane for Excellent Adsorption of Azo Dyes from Wastewater

“…During the last decade, there has been a great interest in developing dye-adsorbent hydrogels with high adsorption and regeneration capacity to meet the ever-increasing demands of industrial wastewater treatment due to water insufficiency. − Generally, organic dyes applied in various manufacturing units, namely, leather, wood and paper, textile, cosmetics, drugs, and other industries, are released into water, resulting in severe water pollution. − Therefore, the efficient removal of dyes from industrial wastewater has raised significant attention in the past few years. − Among various synthetic dyes released in effluents from industries, azo dyes are more harmful due to their several azo groups (−NN−), aromatic rings, and amino groups. − Moreover, the cyclic aromatic structures of azo dyes are highly carcinogenic and stable in the environment, creating colossal damage to the living beings and the surrounding environment . It is necessary to eliminate azo dyes from wastewater to reduce the worldwide water problems faced by society.…”

Unnatural Amino Acid: 4-Aminopyrazolonyl Amino Acid Comprising Tri-Peptides Forms Organogel With Co-Solvent (EtOAc:Hexane)

“…The process of gelation by ultrasound could involve breaking the larger aggregates or disordered aggregates to induce the formation of well-defined larger uniform aggregates which may lead to the formation of gels ( Chatterjee and Maitra, 2017 ). The peptide-based organogels are biocompatible materials and considered promising biomaterials for various applications such as drug delivery ( Couffin-Hoarau et al, 2004 ; Baral et al, 2014 ; Rouse et al, 2017 ), oil recovery in the petroleum industry ( Chetia et al, 2020 ), and removal of toxic dyes ( Li et al, 2020 ). Recently, the sequence-specific small peptides are explored to prepare thermally stable reversible/irreversible organogel biomaterials from natural/unnatural/hybrid peptides ( Chakraborty et al, 2002 ; Banerjee et al, 2008 ; Maity et al, 2015 ; Wang and Yan, 2018 ).…”

Cholesterol‐Modified Quinazoline: Gelation, Ag+ and Al3+ Ion Detection under Different Conditions and Phase Selective Dye Removal with an Ag‐gel

“…Exploitation of this technique in removal of dyes from wastewater also draws attention for the ease of process. [48][49][50][51] In this regard, a reasonably high mechanical strength of the gel-material as well as its high temporal stability makes the gelator suitable for such application.…”

“…Importantly, phase selective gelation is unique in removal of oil or water‐immiscible solvents from a biphasic mixture. Exploitation of this technique in removal of dyes from wastewater also draws attention for the ease of process [48–51] . In this regard, a reasonably high mechanical strength of the gel‐material as well as its high temporal stability makes the gelator suitable for such application.…”