Adsorption of cadmium by a high-capacity adsorbent composed of silicate-titanate nanotubes embedded in hydrogel chitosan beads. Issue 23 (14th October 2020)

• Record Type: Journal Article
• Authors: Quiroga-Flores, Roxana; Noshad, Asma; Wallenberg, Reine; Önnby, Linda
• Is Part Of: Environmental technology. Volume 41:Issue 23(2020)
• Page Start: 3043
• Page End: 3054
• Publication Date: 2020-10-14
• Subjects: Silicate-titanate nanotubes -- chitosan beads -- cadmium -- adsorption -- reuse; Environmental engineering -- Periodicals; Environmental protection -- Periodicals; 628.05
• DOI: 10.1080/09593330.2019.1596167
• Languages: English
• ISSNs: 0959-3330

Abstract

ABSTRACT: In this study, we developed a nanoparticle-based mesoporous composite that consisted of silicate-titanate nanotubes (STNTs) supported in hydrogel chitosan beads (STNTs-Ch beads) and was studied for Cd 2+ adsorption. By using Fourier-transform infrared spectroscopy, transmission and scanning electron microscopy coupled to an energy-dispersive X-ray spectrometer, we could determine that the hollow STNTs were highly dispersed in the walls of the hollow beads. The dispersion was attributed to the effect of pH when the composite was prepared and we observed a non-interaction between STNTs and chitosan. The adsorption studies of Cd 2+ showed that the kinetic rate ( k 2 ) increased 3-fold and that the diffusion rate ( K d ) increased 2-fold after the embedment. Moreover, the maximum capacity of adsorption of STNTs-Ch beads was 2.3 times higher than that of STNTs alone. The treatment of a synthetic Cd 2+ solution and a real leachate in continuous mode showed two phases in which it was observed higher removed fractions of transition metal ions (Cd 2+, Co 2+, Ni 2+, Zn 2+ and Cu 2+ ) and the post-transition metal ion Pb 2+, in comparison to the removed fractions of alkali and alkali-earth metal ions (Ca 2+, K +, Mg 2+ ). The composite was successfully reused four times when adsorbing Cd 2+, saving three times the needed amounts of TiO2, SiO2 and chitosan for the production of the material. This composite was produced in a simple way and shows the potential for wastewater treatment. GRAPHICAL ABSTRACT: UF0001