A novel Fe-Chitosan-coated carbon electrode sensor for in situ As(III) detection in mining wastewater and soil leachate

A novel As(III) sensor was developed by co-electrodepositing a Fe-Chitosan composite to a screen-printed carbon electrode sensor. The newly developed Fe-Chitosan-coated carbon electrode sensor exhibited successful As(III) detection in mining wastewater and soil leachate using square wave anodic stripping voltammetry (SWASV). A noticeable peak was observed at +0.15 V associated with stripping current of As(III) for both real wastewater samples. The calibration curves showed strong correlations with respect to As(III) with the limit of detection (LOD) of 1.12 ppb for mining wastewater and 1.01 ppb for soil leachate, respectively. Lower relative standard deviations (RSD) were obtained with 2.91% for mining wastewater and 4.54% for soil leachate during repeated measurements (n=8), respectively, indicating enhanced stability for As(III) detection in the real wastewater application. The interference from copper and other metal ions (e.g., Zn(II), Pb(II) and Cd(II)) was found negligible for As(III) detection using the polymer modified Fe-coated electrode sensor, which suggests that the Fe-chitosan composite imparted the selectivity in the presence of other metal ions to As(III) detection in complex water matrix. These results demonstrate the applicability of a novel Fe-Chitosan-coated carbon electrode sensor to real wastewater As(III) pollution monitoring with the acceptable range of characteristics.