Microwave-Assisted Rapid Synthesis of Reduced Graphene Oxide-Based Gum Tragacanth Hydrogel Nanocomposite for Heavy Metal Ions Adsorption

Abstract

Reduced graphene oxide (RGO) was synthesized in this research via Tour’s method for the use of filler in the hydrogel matrix. The copolymerization of N,N-dimethylacrylamide (DMA) onto the gum tragacanth (GT) was carried out to develop gum tragacanth-cl-N,N-dimethylacrylamide (GT-cl-poly(DMA)) hydrogel using N,N'-methylenebisacrylamide (NMBA) and potassium persulfate (KPS) as cross-linker and initiator correspondingly. The various GT-cl-poly(DMA) hydrogel synthesis parameters were optimized to achieve maximum swelling of GT-cl-poly(DMA) hydrogel. The optimized GT-cl-poly(DMA) hydrogel was then filled with RGO to form reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide (GT-cl-poly(DMA)/RGO) hydrogel composite. The synthesized samples were used for competent adsorption of Hg2+ and Cr6+ ions. Fourier transform infrared, X-ray powder diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy were used to characterize the gum tragacanth-cl-N,N-dimethylacrylamide hydrogel and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide hydrogel composite. The experiments of adsorption-desorption cycles for Hg2+ and Cr6+ ions were carried out to perform the reusability of gum tragacanth-cl-N,N-dimethylacrylamide hydrogel and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide hydrogel composite. From these two samples, reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide exhibited high adsorption ability. The Hg2+ and Cr6+ ions adsorption by gum tragacanth-cl-N,N-dimethylacrylamide and reduced graphene oxide incorporated gum tragacanth-cl-N,N-dimethylacrylamide were best suited for pseudo-second-order kinetics and Langmuir isotherm. The reported maximum Hg2+ and Cr6+ ions adsorption capacities were 666.6 mg g-1 and 473.9 mg g-1 respectively.

Spinel Ferrite Based Nanomaterials for Water Remediation Application

“…For example, spinel ferrite nanoparticles have a greater positive charge at a lower pH and a greater negative charge at a higher pH. This statement supports anion adsorption at lower pH and cation adsorption at higher pH [61]. For example, the best adsorption of Mo(VI) 33.4 mg g -1 on γ-Fe2O3 nanoparticles between pH 4 and 6.…”

A Short Review on the N,N-Dimethylacrylamide-Based Hydrogels

“…At low pH values, the amine group protonates and easily adsorbs the Cr 6+ ions in the form of HCrO 4 − ( Figure 3 a). The mechanism of the adsorption is given in Figure 3 [ 44 ].…”

“…The adsorption kinetics and isotherms of Cd 2+ were calculated [ 48 ]. The same procedure was used for the synthesis of gum tragacanth-cl-N,N-dimethylacrylamide (GT-cl-poly(DMAA)) hydrogel [ 44 ]. In similar way, starch-grafted poly(N,N-dimethyl acrylamide) hydrogel was synthesized.…”

ZrO2 Nanoparticles and Poly(diallyldimethylammonium chloride)-Doped Graphene Oxide Aerogel-Coated Stainless-Steel Mesh for the Effective Adsorption of Organophosphorus Pesticides

“…Graphene aerogel (GA) has attracted more and more attention in different fields since its emergence in 2013 towing to the super large specific surface area, excellent mechanical properties, high porosity, and low density [ 21 , 22 , 23 ]. As a desirable sorbent, porous and amphiphilic GA was designed and prepared for the adsorption and preconcentration of environmental pollutants [ 24 , 25 , 26 , 27 ]. Although the 3D frame structure of GA can provide many adsorption sites, it has the disadvantage of a single structure with the poor adsorption selectivity for OPPs.…”