Selective adsorption of Ag+ by silica nanoparticles modified with 3-Amino-5-mercapto-1,2,4-triazole from aqueous solutions

A novel adsorbent was synthesized via modifying silica nanoparticles with 3-Amino-5-mercapto-1,2,4-triazole and was used to selectively adsorb silver ions from aqueous solutions. The adsorbent was confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscope and Brunauer-Emmett-Teller (BET) surface area analysis. Batch adsorption experiments were carried out to evaluate the adsorption conditions, reusability and selectivity. The results showed that the optimum pH is 5 and the maximum adsorbability was 124.52 mg/g. The adsorption rate was very high and equilibrium was achieved within 20 min. The total adsorption process preferably followed the pseudo-second order kinetics and the Langmuir isotherm model. The sorbent was stable and efficient. After used five times, the adsorbability was 98.72% of the initial adsorbability. Moreover, the adsorbent adsorb selectively Ag+ from coexisting ions in aqueous solution.