PORTABLE COLORIMETRIC DETECTION OF Hg2+ IN WATER USING ECO-FRIENDLY PAPER-BASED SENSOR

Abstract

Mercury is among the most hazardous heavy metals in aquatic systems due to its toxicity, persistence, and bioaccumulation, posing significant risks to ecosystems and human health. This study presents a sustainable, and low-cost approach for Hg2+ detection based on green-synthesized silver nanoparticles (AgNPs). AgNPs were prepared using an ethanolic extract of Juglans regia as a natural reducing and stabilizing agent and immobilized onto filter paper to fabricate a portable colorimetric sensor for Hg2+ detection. The sensing mechanism is based on the specific interaction between Hg2+ and AgNPs, producing a distinct color change visible to the naked eye. The sensor exhibited a linear detection range from 1×10-3 to 1×10-8 mol dm-3, with a limit of detection of 1.065×10-8 mol dm-3. The proposed platform offers eco-friendly synthesis, low production cost, portability, and instrument-free operation, making it a promising candidate for rapid on-site monitoring of Hg2+ contamination in water.