Detection of thiourea from electrorefining baths using silver nanoparticles-based sensors.

I. PEDRE; F. BATTAGLINI; G. LABRADA-DELGADO; M.G. SÁNCHEZ LOREDO; G.A. GONZALEZ

SENSORS AND ACTUATORS B-CHEMICAL

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2015 vol. 212 p. 515 - 522

0925-4005

tA novel and easy-to-use colorimetric thiourea (TU) sensor based on immobilized polyvinylpyrrolidone-stabilized silver nanoparticles (PVP-AgNPs) is reported. The new sensor is aimed for its direct applicationin copper electrorefinery baths. Quantitative analysis was carried out by adding different thioureaamounts into a synthetic bath and monitoring the absorption changes of the surface plasmon resonanceband (SPRB) by UV?Vis spectrophotometry. A linear correlation between the absorbance change andthiourea concentration was obtained, ranging from 0.125 mg/L to 1 mg/L. Our technique has the advan-tage of working in acidic and high ionic concentrated solutions as those used in electrorefinery baths. Theinfluence of the nanoparticles synthesis conditions on the thiourea sensing was analyzed; particularly,the effect of using different silver concentrations and the same amount of borohydride ions as reducingagent ([Ag+]/[BH4−] ratios of 2:1, 8:1, 10:1 and 20:1 during the synthesis). The proposed system providesa simple, economical, easy-to-handle and rapid measurement tool for monitoring hydrometallurgicalprocesses for optimizing the reconditioning of thiourea solutions, reducing its environmental impact.