Synthesis of New Hydrogels Involving Acrylic Acid and Acrylamide Grafted Agar-Agar and Their Application in the Removal of Cationic Dyes from Wastewater

Abstract

Polyacrylic Acid grafted Agar-agar (AAc-graf-Agar), and polyacrylamide grafted Agar-Agar (AAm-graf-Agar) have been synthesised by free radical polymerisation route initiated by ammonium peroxodisulphate (APS), the grafted polymers were characterised by FTIR, TGA and SEM methods. The swelling properties were studied in deionised water and saline solution at room temperature. The prepared hydrogels were examined by removing cationic methylene blue (MB) dye from the aqueous solution, in which the adsorption kinetics and isotherms models were also investigated. It was found that the pseudo-second-order and Langmuir equations are the most suitable for the different sorption processes. The maximum dye adsorption capacity was 1035.96 mg∙g−1 for AAc-graf-Agar in pH medium 12 and 1015.7 mg∙g−1 for AAm-graf-Agar in neutral pH medium. This indicates that the AAc-graf-Agar hydrogel could be an excellent adsorbent for removing MB from aqueous solutions.

Removal of Malachite Green by Poly(acrylamide-co-acrylic acid) Hydrogels: Analysis of Coulombic and Hydrogen Bond Donor–Acceptor Interactions

“…Betraoui et al [49] conducted a study on the swelling degree of AAc-graf-Agar and AAm-graf-Agar hydrogels in both deionized water and salt water containing 0.9 wt % NaCl. The AAc-graf-Agar hydrogel reached a swelling equilibrium of 6000 wt % and 2800 wt % in deionized water and salt water, respectively.…”

Agar Graft Modification with Acrylic and Methacrylic Acid for the Preparation of pH-Sensitive Nanogels for 5-Fluorouracil Delivery

“…Examples of anionic monomers are acrylic acid, methacrylic acid, propionic acid, ethylenesulfonic acid, styrenesulfonic acid, and cationic monomers include acrylamide, aminoethyl methacrylate, N,N′-dimethylaminomethylacrylamide, N,N′-dimethylaminoethyl methacrylate, N,N′-dimethylaminopropyl methacrylate, N,N′-diethylaminoethyl methacrylate, diallyldimethylammonium chlorid [ 18 ]. Acrylic and methacrylic acid have been employed to graft modification of agar for various purposes including waste water treatment, antimicrobial properties, or drug delivery [ 19 , 20 , 21 , 22 ]. Agar is a natural unbranched hydrophilic polysaccharide.…”