Terbium Removal from Aqueous Solutions Using a In2O3 Nanoadsorbent and Arthrospira platensis Biomass

Terbium is a rare-earth element with critical importance for industry. Two adsorbents of different origin, In(2)O(3)nanoparticles and the biological sorbent Arthrospira platensis, were applied for terbium removal from aqueous solutions. Several analytical techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy, were employed to characterize the adsorbents. The effect of time, pH, and terbium concentration on the adsorption efficiency was evaluated. For both adsorbents, adsorption efficiency was shown to be dependent on the time of interaction and the pH of the solution. Maximum removal of terbium by Arthrospira platensis was attained at pH 3.0 and by In2O3 at pH 4.0-7.0, both after 3 min of interaction. Several equilibrium (Langmuir, Freundlich, and Temkin) and kinetics (pseudo-first order, pseudo-second order, and Elovich) models were applied to describe the adsorption. The maximum adsorption capacity was calculated from the Langmuir model as 212 mg/g for Arthrospira platensis and 94.7 mg/g for the In2O3 nanoadsorbent. The studied adsorbents can be regarded as potential candidates for terbium recovery from wastewater.

Automated summary

In this study, In2O3 nanoparticles and Arthrospira platensis were used as adsorbents for terbium removal from aqueous solutions. The adsorption efficiency of both adsorbents was found to be dependent on the time and pH, with Arthrospira platensis showing the highest removal at pH 3.0 and In2O3 at pH 4.0-7.0. The maximum adsorption capacity calculated from the Langmuir model was 212 mg/g for Arthrospira platensis and 94.7 mg/g for In2O3 nanoadsorbent. These adsorbents have potential for terbium recovery from wastewater.