Development and application of a nano-coated selective electrode for detection of iron in wastewater

Abstract

This study investigates the possibility of determining iron in wastewater by green chemistry method, including developing an iron selective electrode coated with nano CG-FeO- NPs extracted from mint leaves. The developed electrode was characterised using AFM, SEM, XRD and IR technologies. The performance of the new electrode was optimised for the effects of the pH, temperature and response time. The results showed that the electrode works efficiently in a pH range of 5-8, a temperature range of 20-30 <sup>o</sup>C, and a response time of 6-88 seconds. The calibration curve was range line response from 10<sup>-1</sup> to 10<sup>-11</sup> with a slope of -28.727 mV/decade, a correlation coefficient of 0.9997, a detection limit of 2.4×10<sup>-10</sup> M, a lifetime of 48 days and a recovery percentage of 98.5-99,80 for concentrations of 10<sup>-2</sup>,10<sup>-3</sup> and 10<sup>-4</sup>. A selectivity test was also carried out to ensure no interferences with other elements such as zinc, potassium, sulfate, lead, calcium and manganese. Measurements proved that the electrode has high selectivity towards iron ions only and not other elements. Applications were carried out using the standard addition method on an industrial water model and gave a correlation coefficient of 0.9999.