Assessment of enhanced nitrite removal and monitoring using ligand modified stable conjugate materials

Abstract

Abstract In this study, stable conjugate material was fabricated by functional organic ligand embedded onto the porous silica for efficient detection and adsorption of toxic nitrite (NO2−) ions from contaminated water. The detection method was obviously detected the NO2− ions even in the ultra-trace amount with significant color formation. Several experimental frameworks, including pH effect, reaction time, low limit detection, competing ions effect, maximum removal capacity and reuses were investigated systematically both in the detection and removal operations. The low limit of detection was 0.16 µg/L, which was compiled the high-sensitivity detection of the NO2− ions. The solution pH was displayed a key factor, and it was optimized carefully. The optimum pH was 5.50 both in the detection and adsorption mode in this study. The contact time showed that the kinetics performance was slow compared with previous several nanomaterials. This was postulated that the NO2− ions removed as monovalent and consisted in wastewater as anions. The adsorption trend was highly competent according to Langmuir isotherms, and the highest removal capacity was 119.22 mg/g by the conjugate materials for NO2− ions. Several cations and anions were tested as the competing ions, however, these were not affected the NO2− ion in both operations as the strong affinity of the conjugate materials functionality was expected to the NO2− ions at suitable conditions. The data also emphasized that the conjugate material has potentiality under the suitable experimental protocol for the NO2− ions capturing from the polluted waters. Thus the conjugate materials will attract the scientific community in as promising material in nanotechnology for NO2− ions capturing.