Mesoporous nanosensors for sensitive monitoring and removal of copper ions in wastewater samples

Abstract

In this report, we employ a simple, fast and in situ assessment method for the sensing and uptake of copper in wastewater. The monitoring and uptake of copper ion concentration with a highly selective, sensitive, accurate, rapid and simple protocol in wastewater were successfully investigated. Ball like structures of uniform mesoporous silica nanospheres (MSN) with multi-diffused spaces were utilized as a platform in the fabrication of optical chemosensors in the determination of the Cu²⁺ ions in wastewater samples. The nanosphere carriers are fabricated via ammonia catalytic hydrolysis in the presence of a templating agent in a mixed solvent at ambient temperature. The high surface area of the sphere like structure allows for the loading of the Cu²⁺ ion chromophore in fluorescein hydrazine salicylaldehyde (FHS). The fabricated chemosensors are prepared in a simple process via direct immobilization without any agent. The fluorescein hydrazine derivative immobilized onto the mesoporous silica nanosphere that carries FHNS allows for the monitoring of Cu²⁺ ions and the colour changes from yellow to brown in a few seconds. The engineering of FHNS optical chemosensors shows a high sensitivity and lower limit of detection than the permissible limits in wastewater (2.7 × 10⁻¹⁰ mol L⁻¹). The removal features of the fabricated FHNS were analysed and the adsorption capacity was calculated (581.4 mg g⁻¹) for capturing Cu²⁺ ions. Our findings show strong evidence that the optical chemosensors will be utilized as a promising industrial means for the sensing and adsorption of copper ions.