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The thermodynamic parameters (▵ G°, ▵H° and ▵S°) for adsorption of acrylic acid on CaO2 nanoparticle were estimated in the temperature range of 300.15 - 313.15 K, which helps to evaluate the feasibility of adsorption process, nature of adsorption process and affinity of adsorbent toward solute molecule. A dynamic adsorption study in a fixed-bed column was performed using CaO2 nanoparticle for the recovery of acrylic acid from aqueous stream. The breakthrough curves of adsorption system were obtained for different process variables, such as initial acrylic acid concentration (2882-7206 mg L-1), flow rate (5-9 mL min-1) and bed height (10-20 cm). The bed-depth service time model, Thomas model, Yoon-Nelson model and deactivation kinetic model were applied to the experimental data to predict the column performance. The data were in good agreement with the deactivation kinetic model. The presented results may be useful for the design of adsorption system using nanoparticles, which can be further extended to other systems. [ABSTRACT FROM AUTHOR]

Recovery of acrylic acid from aqueous solution using low-cost CaO2 nanoparticles was investigated. CaO2 nanoparticles were synthesized by co-precipitation technique and characterised using XRD and FTIR. A mechanism was proposed for adsorption of acrylic acid onto CaO2 nanoparticles based on FTIR analysis. Acrylic acid recovery is highly dependent on contact time, CaO2 nanoparticle dosage, initial acrylic concentration and temperature. Langmuir, Freundlich, Dubinin-Radushkevich, Tempkin, Hill, Redlich-Peterson, Sips and Toth isotherms were used and well represented by Redlich-Peterson isotherm (R2 = 0.9998) as compared to other isotherms. Kinetic studies revealed pseudo-second-order kinetics (k2 = 1.962·10-4 g m-1 min-1) for adsorption of acrylic acid onto CaO2 nanoparticles. CaO2 nanoparticles exhibited high acrylic acid recovery over varied concentration ranges. The acrylic acid can be regenerated by desorption from the surface of adsorbent and utilised for numerous applications. The presented results may be useful for the design of adsorption system using nanoparticles, which can be extended to other systems. [ABSTRACT FROM AUTHOR]