Removal of yttrium (III) from aqueous solution using surface metal sequestration methodology by 3‑azo‑phenolate salicylic acid

Abstract

Surface metal sequestration methodology (SMSM) has been explored for efficacious static removal of yttrium ions using 3‑azo‑phenolate salicylic acid (3APSA) as a sequestering reagent. The validity of SMSM was confirmed by monitoring and optimizing the cycle number, pH, reaction time, initial yttrium ions concentration, surface area and temperature. The successive deposition of yttrium on a solid glass substrate-deposited-3APSA was confirmed from the FT-IR, SEM and TGA analyses. The chemical structure of assembled film material was Y(III)-(3APSA)·2H2O complex. The maximum surface coverage value was found 2400 μg/cm2 via application of 10 dipping cycles, 5 min reaction time and pH 6.0. The gathered adsorption data of yttrium (III) by SMSM were fitted to the Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models and the superior suitability was achieved by the Freundlich model (R2 = 0.9914, Kf = 0.52 L/mg). The kinetic studies illustrated that the deposition process of Y(III)-(3APSA)·2H2O complex was identified to follow up the pseudo-second order model with R2 = 0.9968 and the rate constant was corresponding to 1.31 g/mg min. The thermodynamic parameters for removal of yttrium ions were monitored by applying five different temperatures and the outlined results proved the removal of yttrium (III) ions by SMSM via spontaneous processes. The positive value of ΔH° (9.08 kJ/mol) confirmed the endothermic nature of deposition process.