AgCO-halloysite nanotubes composite with enhanced removal efficiency for water soluble dyes.

The release of water soluble dyes into the environment is an utmost concern in many countries. This paper presents the effects of AgCO-halloysite composites on the efficient removal of water soluble dyes. In this study, NaHCO solution was added dropwisely to halloysite nanotubes (HNTs) dispersed in aqueous AgNO to form AgCO-HNTs composite. The synthesized AgCO-HNTs composite was characterized with Diffused Reflectance Spectroscopy (DRS), X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDX) and Fourier Transform Infra-Red (FT-IR) spectroscopy. The photocatalytic activity and the adsorption capacity of AgCO-HNTs on methylene blue and rhodamine b dyes were dependent on pH and the amount of HNTs used in the synthesis. The photodegradation efficiency of AgCO was lower when compared with that of the composite material. This observation is due to the reduction in the electron-hole recombination with the HNTs acting as electron trapping site and the enhanced aqueous dispersity of AgCO-HNTs. The enhanced adsorption of water soluble dyes by the AgCO-HNTs resulted from the electrostatic attraction of cationic dyes to the surface of the HNTs (negatively charged). The AgCO-HNTs therefore removed dye pollutants through a combination of photocatalytic and adsorption processes. The results obtained during the study confirmed the potential application of AgCO-HNTs composite in water treatment technologies.