Novel Superadsorbent Highly Porous Hydrogel Based on Arabic Gum and Acrylamide Grafts for Fast and Efficient Methylene Blue Removal

Abstract

Environmental pollution with dyes released from industrial effluent is one of the major and most critical problems in the world. To alleviate this issue, advanced and safe materials with fast and highly efficient dye removal should be designed. Great attention has been paid recently to hydrogels based on polysaccharides such as Arabic Gum (AG) grafted with polyacrylamide (PAM) and polyacrylic acid (PAA). These materials combine the merits of natural polymers such as biodegradability and non-toxicity with the high adsorption ability of PAM and PAA towards cationic dyes such as methylene blue (MB). Many previous works have been done to enhance three-dimensional (3D) structure and swelling ability of the graft copolymers by using a crosslinking agent or even adding nanomaterials as a filler inside the hydrogel matrix. However, these additives may negatively affect the adsorption ability, and few previous studies could reach 2000 mg/g of maximum MB capacity removal within a good period of time. In our work, we synthesized partially hydrolyzed polyacrylamide grafted Arabic gum (AG-g-PAM/PAA) to have both amide and carboxylate groups. The modified water dissolved graft product undergoes water in oil (W/O) emulsion using paraffin oil as the continuous phase and Triton X-100 as a stabilizing agent; then, the system was inversed to oil in water (O/W) emulsion by increasing the shear mixing rate and cross-linked using Epichlorohydrin (ECH). The precipitated graft product showed hierarchically interconnected micro and macropores’ sponge like shape with fast water swelling and high MB adsorption capacity (2300 mg g−1) after 45 min at near neutral pH conditions.

Nanoporous Sodium Carboxymethyl Cellulose-g-poly (Sodium Acrylate)/FeCl3 Hydrogel Beads: Synthesis and Characterization

“…Hydrogels are gaining significant attention of the researchers due to their application in various research fields, such as wastewater treatment, agriculture, tissue engineering, drug delivery and electroactive applications [ 1 , 2 , 3 , 4 ]. Currently, researchers have focused on the development of polysaccharide-based hydrogels due to their cost effectiveness, biodegradability and higher ability to remove pollutants as compared to synthetic polymeric hydrogels [ 5 , 6 , 7 ]. As polysaccharide, sodium carboxymethyl cellulose (CMC) is a high-molecular weight anionic polymeric material that contains numerous hydroxyl (–OH) and carboxylate (–COO – ) groups [ 8 ].…”

Hydroxyethyl cellulose hydrogel modified with tannic acid as methylene blue adsorbent

“…However, the strongly cross‐linked rigid structure obstructed network expansion of the gels in water with further increasing the TA content, it leaded to the decrease of the swelling rate 49 . In generally, the high swelling ratio can increase the surface area, allowing more adsorption sites to be completely exposed to MB dye 50 …”

“…49 In generally, the high swelling ratio can increase the surface area, allowing more adsorption sites to be completely exposed to MB dye. 50 3.4 | Factors affecting the MB adsorption…”

Cellulose-Based Hydrogels for Wastewater Treatment: A Concise Review

“…This HG showed the adsorption of Methylene Blue (MB) with a capacity of 200 mg/g from an aqueous solution. The results revealed an ability of the novel porous HG to adsorb 99% of dye in only 10 min [ 96 ]. In addition to that, HGs based on sodium carboxymethyl cellulose and acrylic acid were prepared by inverse emulsion polymerization using potassium persulfate as an initiator and N,N′-methylenebisacrylamide as a crosslinker.…”