Catalytic Degradation of Methyl Orange and Selective Sensing of Mercury Ion in Aqueous Solutions Using Green Synthesized Silver Nanoparticles from the Seeds of Derris trifoliata

In the present study, bio-augmented silver nanoparticles with Derris trifoliata seed extract (AgNP-DT) have been developed. Formation of AgNP-DT has been confirmed with X-ray diffraction (XRD), High resolution transmission electron microscopy (HRTEM) and Fourier-transform infrared spectroscopy (FTIR). Even though introduced for the first time as a catalyst owing to high surface area, the as-prepared nanoparticles showed one of the best catalytic activity in the reduction of a water soluble azo dye-methyl orange. An incredible pseudo-first order rate constant (0.3208min(-1)) and activity parameter (1086s(-1)g(-1)) were obtained for the catalytic reduction of methyl orange with 4.9g AgNP-DT. Furthermore, AgNP-DT exhibits a good selectivity and sensitivity towards mercury(II) ions over other metals in aqueous solution. Absorbance of AgNP-DT exhibits a good linear relationship against concentration of Hg2+ with a limit of detection (LOD) of 1.55M. The mechanism of sensing activity of AgNP-DT was elucidated by measuring the variation in the zeta potential of the system with increasing concentration of Hg2+. Moreover the proposed method could be practicably applied for the detection of Hg2+ in real water samples with a percentage recovery in range of 91.41-108.07%. [GRAPHICS] .