A Cu(II)-interference-resistant SPE/UiO-66 integrated with a portable electrochemical device for detection of Cd(II)...

Cd(II) in electroplating wastewater can cause serious harm to the environment and human health. Although portable electrochemical equipment enables rapid on-site detection, the interference of Cu(II) affects the detection accuracy of Cd(II). To address this issue, we developed a novel sensor (SPE/UiO-66) with anti-Cu(II) interference properties and integrated it with portable electrochemical equipment. Experiments indicate that when both Cd(II) and Cu(II) concentrations are at 100 µg/L, the signal of Cd(II) on screen-printed electrode (SPE) is completely suppressed, whereas SPE/UiO-66 maintains 91% of the Cd(II) signal intensity. The SPE/UiO-66 exhibits excellent performance: a detection range of 50-200 µg/L and a limit of detection of 17 µg/L. Even if the electroplating wastewater contains a high concentration of Cu(II) (500 and 1000 µg/L), the recovery of Cd(II) after pretreatment with potassium ferricyanide can still reach 96% and 108%, respectively. The experiments and theory calculations revealed that UiO-66 enhances the adsorption capacity for Cu(II), causing Cu(II) to preferentially adsorb on UiO-66 rather than replace nearby Cd, thereby effectively alleviating the interference from Cu(II). This study provides a reliable portable electrochemical device for detecting Cd(II) in electroplating wastewater, which is of significant importance for environmental pollution prevention and control.