Recovery of Acrylic Acid Using Calcium Peroxide Nanoparticles: Synthesis, Characterisation, Batch Study, Equilibrium, and Kinetics

Recovery of acrylic acid from aqueous solution using low-cost Ca[O.sub.2] nanoparticles was investigated. Ca[O.sub.2] nanoparticles were synthesized by co-precipitation technique and characterised using XRD and FTIR. A mechanism was proposed for adsorption of acrylic acid onto Ca[O.sub.2] nanoparticles based on FTIR analysis. Acrylic acid recovery is highly dependent on contact time, Ca[O.sub.2] 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 ([R.sup.2] = 0.9998) as compared to other isotherms. Kinetic studies revealed pseudo-second-order kinetics ([k.sup.2] = 1.962 10 4 g [mg.sup.-1] [min.sup.-1]) for adsorption of acrylic acid onto Ca[O.sub.2] nanoparticles. Ca[O.sub.2] 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.Keywords: acrylic acid, adsorption, calcium peroxide nanoparticles, equilibrium, kinetics, batch study