Sustainable Synthesis of Metal–Organic Frameworks from Waste Material for Electrochemical Sensing of Heavy Metal Ions in Aqueous Media

High Resolution Image Download MS PowerPoint Slide A civilization cannot exist without pure water, but due to urbanization, industrialization, and ecosystem imbalance, people face clean water scarcity. To tackle this situation, recycling and reusing nonbiodegradable waste can become efficient steps both for humans and the environment. So, this research focused on the ecofriendly synthesis of a calcium-based metal–organic framework (Ca-MOF) using terephthalic acid (source: waste plastic (PET)) and a calcium source, enabling the detection of heavy metal (Pb 2+ ) ions while integrating plastic recycling with environmental sensing. Several sophisticated instruments, such as FESEM, FTIR, XRD, TGA, and DSC, were utilized to characterize the synthesized sample. The XRD data confirmed the formation of terephthalic acid and the Ca-MOF. The FTIR spectrum assured the presence of aryl (aromatic) groups and the −COOH group for terephthalic acid, whereas the presence of O–H, O–C–O, and Ca–O was assured for the Ca-MOF. The TG analysis of the Ca-MOF revealed the five stages of mass change as a function of temperature. The particles of the Ca-MOF exhibited a layered, sheetlike structure, as observed through FESEM analysis. In addition, the dielectric properties were examined for the synthesized Ca-MOF. The sensitivity of the Ca-MOF-modified glassy carbon working electrode was explored utilizing potassium ferrocyanide. An electrochemical technique was applied to detect the heavy metal (Pb 2+ ) with a concentration range of 10–0.0001 ppm, along with the surface area calculation. The efficacy of the Ca-MOF-fabricated electrode was explored by utilizing the Laviron and Randles–Sevcik equations.