Design and synthesis of colorimetric sensor based on dithizone@TiO2/poly (tert-butyl acrylate-acrylic acid) nanocomposite for fast visual detection of mercury, lead and cadmium ions in aqueous media

Abstract

This paper presents the selective detection of Hg(II), Pb(II) and Cd(II) in aqueous solution via applications of dithizone(DTZ)@TiO2/poly (tert-Butyl acrylate(TBA)-acrylic acid(AA)) nanocomposites as fast colorimetric sensor. The ion sensing polymeric nanocomposite was prepared by incorporating DTZ as chromoionophore in the polymeric nanocomposite membrane containing TBA as leaving groups. This nanostructured composite with DTZ loaded polymeric shell was utilized as a fast, sensitive and selective sensor for detection of Hg(II), Pb(II) and Cd(II) in aqueous solution at optimum condition. The adsorption of Hg(II), Pb(II) and Cd(II) increased with increasing pH until it reached at around pH = 8.0, pH = 6.0 and pH = 7.0, respectively. The proposed sensor displays a wide linear range of [(10 ppb–10 ppm)], [(20 ppb)] and [(10 ppb)] with a low detection limit of 10 ppb, 20 ppb and 10 ppb for Hg(II), Pb(II) and Cd(II) solutions, respectively, and also this sensor has a relatively quick response time less than 1 min. The DTZ-anchored polymeric nanocomposite is appropriate to use a repeated measures (for more than four cycles) without any noticeable capacity loss. The outstanding properties of synthesized chemosensor are the fast, selective, easy-to-use, portable and inexpensive screening-test for recognizing Hg(II), Pb(II) and Cd(II) contamination in aqueous solution to avoid time-consuming and costly determination using instrumental techniques. The prepared colorimetric sensor were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) analysis, transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and X-ray powder diffraction (XRD).