Preparation of Nitrate Bilayer Membrane Ion-Selective Electrode Modified by Pericarpium Granati-Derived Biochar and Its Application in Practical Samples

• Published in: Electrocatalysis Vol. 14; no. 4; pp. 534 - 545
• Main Authors: Fozia, Zhao, Guangyao, Nie, Yanhong, Jiang, Jianrong, Chen, Qian, Wang, Chaogang, Xu, Xu, Ying, Ming, Hu, Zhangli, Xu, Hong
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.07.2023; Springer Nature B.V
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Electrochemistry; Electrodes; Electron transfer; Energy Systems; Environmental monitoring; Laboratories; Membranes; Nitrates; Nitrogen dioxide; Open circuit voltage; Phosphoric acid; Photoelectrons; Physical Chemistry; Polypyrroles; Selectivity; Wastewater; Nitrate detection; Biochar; Bilayer membrane ion-selective electrode
• ISSN: 1868-2529; 1868-5994
• DOI: 10.1007/s12678-023-00812-3

In this study, a pericarpium granati -derived biochar with phosphoric acid activation (PGCP) was prepared, characterized, and applied together with polypyrrole (PPy) to modify a glass carbon electrode (GCE) to construct a bilayer membrane nitrate ion-selective electrode (ISE, PPy/PGCP/GCE). The morphological results showed that PGCP possessed a porous structures. X-ray photoelectron spectroscopy analysis indicated that phosphorus added in PGCP was in the forms of P-O and P–C. The electrochemical impedance spectrum of the fabricated nitrate ISE showed a very low impedance, suggesting that PGCP can be used as an effective electron transfer mediator. The open circuit potential experiments indicated that the fabricated nitrate ISE exhibited a good linear potentiometric response to nitrate over a wide concentration range of 1 × 10 −5 to 5 × 10 −1  mol·L −1 with Nernstian slope of 50.86 mV·dec −1 at pH range of 3.5–9.5 and a short response time of less than 7.3 s. Its limit of detection (LOD) was determined to be 4.64 × 10 −6  mol·L −1 . Both detection range and LOD are comparable or better than those of reported similar modified electrodes. The fabricated nitrate ISE exhibited a high selectivity with a good repeatability and stability. The selectivity sequence was determined as NO 3 −  > NO 2 −  > Cl −  > H 2 PO 4 −  > CH 3 COO −  > CO 3 2−  > SO 4 2− . The fabricated nitrate ISE was validated by the nitrate detections of real samples from Shenzhen OCT wetland and laboratory wastewater, respectively, with the obtained detection discrepancy of less than 4% (RSD). This study provides useful reference information for the development of novel ISE in clinical laboratories and environmental monitoring.