Radiation synthesis of copolymers for adsorption of dyes from their industrial wastes

Abstract

Copolymer hydrogels were prepared by ␥-radiation copolymerization of N-vinyl-2-pyrrolidone (NVP) and methylmethacrylate (MMA) or acrylonitrile (AN). The effect of NVP/MMA and NVP/AN compositions and irradiation dose on the gel fraction yield in the prepared hydrogels was determined. It was found that as the content of NVP increased, the gel fraction yield decreased. The increase in irradiation dose resulted in increasing the crosslinked network structure and, consequently, the gel percentage increased. The thermal stability and swelling properties were also investigated as a function of comonomer composition. The nitrile groups (-CN) in the prepared copolymer were converted into their respective amidoxime groups by treating with NH 2 OH-hydrochloride. Such a process resulted in improving both the swelling behavior and adsorption capacity. Characterization and some selected properties of the prepared hydrogels were studied and accordingly the possibility of its practicable use in the treatment of industrial waste dyes was determined. The thermodynamic parameters for the adsorption process were calculated. The effect of treatment time, pH of feed solution, effect of initial feed concentration, and temperature on the dye uptake was also investigated. The maximum uptake for investigated dyes was higher for treated NVP/AN hydrogel than that for untreated NVP/AN and NVP/MMA ones.

Adsorption of cationic dyes on poly(acrylic acid‐co‐sodium acrylate‐co‐acrylamide) superabsorbents

“…The ability to absorb large amount of water and other liquids and stimuli responsive behaviour depending on the swelling medium makes them useful in the biomedical field as drug delivery devises4 and contact lenses 5. They are also used for food packaging, water retention of soil6 and water purification 7–9…”

“…In the field of water purification, SAPs have been widely used for the removal of metal ions7, 10, 11 and dyes8, 9, 12, 13 from industrial wastes. The adsorption characteristics of SAPs depend on the nature of the charge on the adsorbent and the adsorbate, fraction of ionic repeat units in the SAPs, initial concentration of the adsorbate, pH and temperature of the medium, and the crosslink density of the polymer.…”

“…Rodriguez and Katime7 have studied the effect of pH and concentration on the uptake of metal ions by acrylic‐acid itaconic acid hydrogels. The effect of treatment time, pH and temperature of the feed solution and effect of initial feed concentration on the dye uptake has been investigated for the radiation synthesized N ‐vinyl‐2‐pyrrolidone/methyl methacrylate and N ‐vinyl‐2‐pyrrolidone/acrylonitrile hydrogels 8. In the study of adsorption of cationic dyes by acrylamide‐maleic acid hydrogels, the effect of crosslinking agents trimethylolpropane triacrylate (TMPTA) and 1,4‐butanediol dimethacrylate (BDMA) and the maleic acid content has been explored 9.…”

Photo, thermal, and ultrasonic degradation of EGDMA‐crosslinked poly(acrylic acid‐co‐sodium acrylate‐co‐acrylamide) superabsorbents

“…They find applications as controlled drug delivery devices2 and contact lenses3 in the biomedical field. They are also used for food packaging, water purification,4–6 and improvement of water retention of soil 7…”

“…They find applications as controlled drug delivery devices 2 and contact lenses 3 in the biomedical field. They are also used for food packaging, water purification, [4][5][6] and improvement of water retention of soil. 7 Some important characteristics of the SAPs are their equilibrium swelling capacity, swelling rate, reversible swelling/deswelling behavior depending on the sur-rounding medium, and ability to adsorb oppositely charged materials.…”