Adsorptive removal of gallium from aqueous solution onto biogenic elemental tellurium nanoparticles

This study investigated the adsorption of gallium onto chemical and biogenic elemental tellurium nanoparticles. Biogenic elemental tellurium nanoparticles (BioTeNPs) were found to be a good adsorbent for the removal and recovery of gallium from aqueous solution with an adsorption capacity of 74 mg of Ga3+ per g BioTeNPs. The adsorption mechanism followed pseudo second order kinetics (R-2 = 0.999) and the experimental data fitted the monolayer adsorption theory-based Langmuir model. BioTeNPs had a size of 5.30-86.1 nm, a negative zeta potential (-32 mV) and were coated with a layer of extracellular polymeric substances (EPS). Further, a high desorption efficiency of 99% from Ga3+ adsorbed onto the BioTeNPs was achieved using oxalic acid (0.1 M) as eluent. This study proposes a novel removal and recovery method for Ga3+ by adsorption on BioTeNPs produced in bioreactors treating tellurium oxyanion rich wastewaters.

Automated summary

This study found that biogenic elemental tellurium nanoparticles are effective adsorbents for the removal and recovery of gallium, with high adsorption capacity and desorption efficiency.