Development of nanomaterial chemosensors for toxic metal ions sensing

Abstract

Heavy metal ions are harmful to aquatic life and humans owing to their high toxicity and non-biodegradability, so their removal from wastewater is an important task. Therefore, this work focuses on designing suitable, simple and economical nanosensors to detect and remove these metal ions with high selectivity and sensitivity. Based on this idea, different types of mesoporous materials such as hexagonal SBA-15, cubic SBA-16 and spherical MCM-41, their chloro-functionalized derivatives, as well as 4-(4-nitro-phenylazo)naphthalen-1-ol (NPAN) azo dye have been synthesized, with the aim of designing some optical nanosensors for metal ions sensing applications. The mentioned azo dye has been anchored into the chloro-functionalized mesoporous materials. The designed nanosensors were characterized using scanning and transmission electron microscopy as well as Fourier transform infrared and UV-visible spectral analysis, nitrogen adsorption-desorption isotherms, low-angle X-ray diffraction and thermogravimetric analyses. Their optical sensing to various toxic metal ions such as Cd (II), Hg (II), Mn (II), Fe (II), Zn (II) and Pb (II) at different values of pH (1.1, 4.9, 7 and 12) was investigated. The optimization of experimental conditions, including the effect of pH and metal ion concentration, was examined. The experimental results showed that the solution pH had a major impact on metal ion detection. The optical nanosensors respond well to the tested metal ions, as reflected by the enhancement in both absorption and emission spectra upon adding different concentrations of the metal salts and were fully reversible on adding ethylene diamine tetra acetic acid or citric acid to the formed complexes. High values of the binding constants for the designed nanosensors were observed at pHs 7 and 12, confirming the strong chelation of different metals to the nanosensor at these pHs. Also, high binding constants and sensitivity were observed for NPAN-MCM-41 as a nanosensor to detect the different metal ions. From the obtained results, we succeeded in transforming the harmful azo dye into an environmentally friendly form via designing of the optical nanosensors used to detect toxic metal ions in wastewater with high sensitivity.

Sudan Blue II Dye loaded modified MCM-48: Colorimetric, Paper Strip, and Fluorescent Sensor for Cu 2+ ion

“…After chlorofunctionalization and the anchoring of SB dye, the adsorption branches were signi cantly shifted toward lower relative pressure (p/p o ). The decrease in surface area, pore volume and pore diameter (Table 1) con rm the presence of SB dye on the surface and pores of the mesoporous materials which partially leads to blockage of N 2 molecules [33]. The SEM image of MCM-48 (Fig.…”

Mercaptosuccinic-Acid-Functionalized Gold Nanoparticles for Highly Sensitive Colorimetric Sensing of Fe(III) Ions

“…In this regard, the development of rapid and cost-effective methods for Fe(III) determination is still an urgent task. To date, a variety of chemosensors for on-site heavy metal ion determination with high sensitivity and ease of use were reported [10][11][12]. Fluorescent techniques are proposed, which are based on the interaction of Fe(III) ions with carbon nanodots [13,14], metal-organic frameworks [15], copper nanoclusters capped with BSA [16], or fluorescent dyes [17,18].…”

Rosaniline Hydrochloride Encapsulated MCM-48: Fluorescent and Electrochemical Sensor for Dopamine

“…Another chitosan@MCM-48 nanocomposite was developed as adsorbent for removing phenol from aqueous waste water [39]. A new study has been reported for metal ion sensing via anchoring an azo dye namely 4-(4-nitro-phenylazo)-naphthalen-1-ol (NPAN) into hexagonal SBA-15, cubic SBA-16 and spherical MCM-41 [40]. Anchoring of another azo dye 1-(2pyridylazo)-2-naphthol (PAN) into functionalised MCM-48 has also been reported for trace determination of copper, cadmium, lead and nickel in water and sea food samples [41].…”