Consecutive removal of heavy metals and dyes by a fascinating method using titanate nanotubes

Abstract

Titanate nanotubes TNT are promising materials for water treatment due to properties. Sodium titanate nanotubes (Na-TNT) were hydrothermally synthesized and characterized using XRD, FESEM, HRTEM, Zeta potential, nitrogen adsorption and desorption, and FT-IR spectra techniques. The efficiency of Na-TNT for adsorption of Ni(II) from water was tested through different conditions including pH, Na-TNT dose, initial metal concentration, and contact time. The results showed efficient adsorption performance with rapid removal of 90 % of Ni(II) ions within the first 15 min and after 30 min, the equilibrium was attained with removal efficiency close to 100 % at pH = 7 and with an adsorption capacity of 181.2 mg/g. Ni-TNT was collected and recycled for the removal of methylene blue (MB) by combined adsorption and photocatalytic degradation. The adsorption efficiency reached (99.5 %) and the equilibrium adsorption capacity was 916 mg/g and 330 mg/g for Ni-TNT and Na-TNT respectively. The correlation coefficient R2, error function Chi2, SSE, and MSE were used to evaluate the best fit models to the experimental data. The adsorption mechanism was explored using density functional theory and Monte Carlo simulation. The photocatalytic activity of Ni-TNT was tested through two different types of experiments. More attention was paid to the effect of the light path length through the dye solution and the effect of the experiment container dimensions on the photocatalytic degradation process. Also, both Na-TNTs and Ni-TNTs showed potent antifungal and antimicrobial activity. This work successfully represents TNT as a multifunctional material.