In2S3 incorporated into CO32−@Ni/Fe/Zn trimetallic LDH as a bi-functional novel nanomaterial for enzymatic urea sensing and removal of sulfur-containing pharmaceutical from aqueous streams

Abstract

The Ni/Fe/Zn trimetallic LDH intercalated with carbonate ions grown over In2S3 nanoparticles to form a novel In2S3/LDH nanocomposite fabricated with the combined efforts of the solvothermal and in-situ precipitation processes, as well as its enzymatic sensing and visible light-induced degradation ability, were thoroughly investigated in this study. The urease-immobilized In2S3/LDH/ITO electrode showed high-performance electrochemical sensing over a wide range of 1–240 µM with a lower limit of detection (LOD) of 0.246 µM and enhanced sensitivity of 2.29 × 10−7 A μM−1 cm−2 in phosphate buffer solution (50 mM, pH 7.5, 0.9 % NaCl) at a scan rate of 50 mV s−1. The fabricated electrode was reusable for up to 15 scans and demonstrated very high selectivity towards urea, as it showed an insignificant change in current, even in the introduction of various interferences. Furthermore, the synthesized In2S3/LDH nanocomposite demonstrated enhanced photocatalytic ability for degradation of 15 ppm of emerging sulfur-containing pollutant pantoprazole with an impressive efficiency of 98.25 ± 1.51 % in 35 min of visible light irradiation, with a high rate constant of 0.1 min−1. The H2O2-assisted AOP process showed improved COD removal of up to 87.31 ± 1.43 %, with high stability and reusability up to 7 consecutive cycles. Moreover, the as-prepared In2S3/LDH nanocomposite also showed significant degradation of other emerging pollutants with a more than 70 % degradation efficiency. As a result, this composite is a potential electrocatalyst for urea sensors in practical analysis, and it also has outstanding photodegradation of pantoprazole under visible light irradiation.