Kinetics of adsorption of methylene blue and rhodamine 6G on acrylic acid‐based superabsorbents

Abstract

Superabsorbent polymers (SAPs) of acrylic acid, sodium acrylate, and acrylamide (AM), crosslinked with ethylene glycol dimethacrylate, were synthesized by inverse suspension polymerization. The equilibrium swelling capacities of the SAPs were determined and these decreased with increasing AM content. The adsorption of the two cationic dyes, methylene blue and rhodamine 6G, on the dry as well as equilibrium swollen SAPs was investigated. The amount of the dye adsorbed at equilibrium per unit weight of the SAPs and the rate constants of adsorption were determined. The amount of the dye adsorbed at equilibrium by the SAPs decreased with increasing mol % of AM in the SAPs. The amount of the dye adsorbed at equilibrium was almost equal for the dry and equilibrium swollen SAPs. However, the equilibrium swollen SAPs adsorbed dyes at a higher rate than the dry SAPs. The higher rate of adsorption was attributed to the availability of all the anionic groups present in the fully elongated conformation of the SAPs in the equilibrium swollen state. The effect of initial dye concentration on the adsorption was also investigated and the adsorption was described by Langmuir adsorption isotherms.

Isotherm Analysis on the Removal of Ni (II) ION from Wastewater using APANC

“…Adsorption isotherm [4][5][6][7][8] describes the relation between the amount or concentration of adsorbate that accumulates on the adsorbent and the equilibrium concentration of the dissolved adsorbate. Equilibrium studies were carried out by agitating a series of beakers containing 50 mL of Ni (II) solutions of initial concentration 20 mg/L with 0.025 g of activated nano carbon at 30 0 C with a constant agitation.…”

“…Which, can be linearized as 1 ln q =lnK + lnC e F e n F (4) Where, q e is the amount of Ni(II) adsorbed at equilibrium (mg/g) and C e is the concentration of Ni(II) in the aqueous phase at equilibrium (ppm). K F (L/g) and 1/n F are the Freundlich constants related to adsorption capacity and sorption intensity, respectively.…”

“…These include oxidation and reduction, chemical precipitation, filtration, electrochemical treatment, ion exchange, membrane separation, reverse osmosis, adsorption, evaporation and electrolysis [2]. However, adsorption has been proven to be one of the best options available for the removal of heavy metals from aqueous solution [3,4]. In view of the above, several researches have been conducted using various materials as adsorbents [5][6][7].…”

Adsorption Isotherm, Kinetic, Thermodynamic and Breakthrough Curve Models of H2S Removal Using CeO2/NaOH/PSAC

“…2 This equilibrium data is crucial and required in the process design of the adsorption systems. 3 There are various models developed such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms.…”

A Study on the Removal Characteristics of Nickel Ion from Wastewater by Low-Cost Nano Adsorbent

“…However, adsorption has been proven to be one of the best options available for the removal of heavy metals from aqueous solution [3]. In view of the above, several researches have been conducted using various materials as adsorbents [4]. However, some of these adsorbents also contain other toxicants; some are expensive and are characterized with limited surface area for adsorption.…”