Novel salep-based chelating hydrogel for heavy metal removal from aqueous solutions

Abstract

A novel optimized chelating hydrogel was synthesized via graft copolymerization of acrylamide and 2-hydroxyethyl methacrylate (as two-dentate chelating co-monomer) onto salep (a multicomponent polysaccharide obtained from dried tubers of certain natural terrestrial orchids) using N,N′-methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. Reaction parameters (N,N′-methylenebisacrylamide and ammonium persulfate amounts as well as acrylamide/2-hydroxyethyl methacrylate weight ratio) affecting the water absorption of the chelating hydrogel were optimized using a systematic method to achieve a hydrogel with high swelling capacity as possible. Heavy metal ion adsorption capacity of the optimized hydrogel for metal ions [Cu (II), Pb (II), Cd (II), and Cr (III)] were investigated in aqueous media containing different concentrations of these ions (5-50 ppm). The results showed that the hydrogel have great potential for heavy metal removal from aqueous solutions. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy, and surface morphology study of the hydrogel was performed by scanning electron microscope.

Hydrogel Adsorbents for the Removal of Hazardous Pollutants—Requirements and Available Functions as Adsorbent

“…Many hydrogels, including poly(acrylic acid) [88], poly(N-isopropyl acrylamide) [89][90][91][92][93][94], poly(N,N-dimethylacetamide-co-2-hydroxyethyl methacrylate) [95], amidoximated poly (methacrylic-co-acrylonitrile) [71], poly(2-hydroxyethyl methacrylate)-grafted copolymer [96], poly(glycidyl methacrylate-glycine) [97], poly(1-vinyl-2-pyrrolidone-co-sodium acrylate) [98], and poly(maleic acid) with cyclic groups of poly (1, 4-dioxa-7, 12-diazacyclotetradecane-8, 11-dione) and poly (1,4-diazocane-5,8-dione) [99,100] have been studied in the last decade to investigate their adsorption properties over various targets. As typical adsorption characteristics of hydrogels, Sammaddar et al (2019) [5] and Qi et al (2021) [64] reviewed the adsorption capacity of the hydrogel adsorbents such as acrylic acid, amine, alginic acid, cellulose and its derivatives, pectin, and chitosan gels for the removal of pollutants from the aqueous system.…”

Natural Salep/PEGylated Chitosan Double Layer toward a More Sustainable pH-Responsive Magnetite Nanocarrier for Targeted Delivery of DOX and Hyperthermia Application

“…So far, different polysaccharides such as chitosan, ,, starch, hyaluronic acid, dextran, and so forth have been used in different types of drug nanocarriers such as core–shell nanoparticles, hydrogels, , micelles, , vesicles, and nanocapsules . Salep, a commonly used additive in the food industries, is a low-cost and newfound polysaccharide in DDSs. , A few researchers have reported on the use of salep in the design and synthesis of smart, responsive drug nanocarriers. − …”

“…39 Salep, a commonly used additive in the food industries, is a low-cost and newfound polysaccharide in DDSs. 40,41 A few researchers have reported on the use of salep in the design and synthesis of smart, responsive drug nanocarriers. 42−45 In the past decade, there has been increasing exploration of core−shell nanocarriers so that they have emerged as a unique class of nanocarriers, which is along with the concept of "surface engineering".…”

Adsoption of Cationic Dye on Anionic Hydrogel and Its Second Use for Drug Delivery with Antibacterial Properties

“…[1][2][3][4]. Stimuli-sensitive polymers have gained great interest recently in the design of intelligent materials for multi purposes such as controlled drug delivery systems, adsorbent for dye removal, heavy metal adsorption, solute separation, artificial organs and enzyme immobilization [5][6][7][8][9][10]. Typical examples of these polymers involve poly(acrylic acid), poly(Nisopropylacrylamide), poly(2-acrylamido-2methyl-1-propanesulfonic acid)(PAMPS), poly(2-(dimethylamino) ethylmethacrylate) [11][12][13].…”