Green synthesized silver nanoparticles for selective colorimetric sensing of Hg2+ in aqueous solution at wide pH range

Abstract

In the present study, the syntheses of crystalline silver and gold nanoparticles (NPs) has been demonstrated in a green and environmentally friendly approach using citrus fruit extracts (lemon, Citrus limon (Cl-1) and sweet orange, Citrus limetta (Cl-2)). In addition, potentially hazardous metal ion sensing properties of these NPs in aqueous solution has been explored. Cl-1 and Cl-2 that predominantly contained citric and ascorbic acid, exhibited different reducing abilities towards silver and gold ions into NPs. Cl-1 reduces silver ions into AgNPs only in the presence of sunlight whereas AuNPs from gold ions were formed without exposure to sunlight. In contrast, Cl-2 converts both silver and gold ions into the corresponding NPs in the absence of sunlight. The colorimetric sensor studies of these green synthesized AgNPs (Cl-1-AgNPs) showed selective sensing of the potentially hazardous Hg(2+) ion in water at micromolar concentrations. More importantly, green synthesized Cl-1-AgNPs sensor systems detected Hg(2+) ions in water in a wide pH range (3.2 to 8.5).

Rapid colorimetric detection of Hg2+ ion by green silver nanoparticles synthesized using Dahlia pinnata leaf extract

“…However, no significant change was observed in the efficacy of the suspension of Ag nanoparticles for detecting Hg 2+ ions throughout the whole range of pH. Therefore, these stable biogenic silver nanoparticles can be used successfully for detection of hazardous Hg 2+ ions in water and further protect the environment from hazardous mercury pollution [38,42].…”

“…The mechanism of Hg 2+ detection by suspension of Ag nanoparticles can be explained by the electrochemical differences between these two metal ions: Hg 2+ and Ag + . The reduction potential of Ag + is +0.80 V (Ag + +e = Ag) whereas the standard reduction potential for Hg 2+ is +0.92 V (2Hg 2+ +2e = Hg 2 2+ ) [38]. According to the electrochemical series, the higher reduction potential of the metals signifies better oxidizing abilities [39].…”

Application of Starch-Stabilized Silver Nanoparticles as a Colorimetric Sensor for Mercury(II) in 0.005 mol/L Nitric Acid

“…This way, detection of very low environmentally relevant Hg contents is possible. Several sensing systems have been already reported based on the interaction between AgNPs and Hg(II) ions [23][24][25][26][27][28][29][30][31][32]; however, detailed study of Hg behavior in the presence of another competitive oxidant is rarely performed and discussed. A dual functional sensor for determination of Hg and H 2 O 2 has been developed based on a similar approach: addition of H 2 O 2 to a mixture of AgNPs and Hg(II) ions [33].…”

Biosynthesis of silver nanoparticles using aqueous leaf extract of Thevetia peruviana Juss and its antimicrobial activities

“…In its nanoscale form, silver exhibits unique physicochemical and biological activities. This has made them useful as sensor, vector control, antimicrobial, anticancer, and antiplasmodial agents, catalysts, among others (Elemike et al 2014;Ashokkumar et al 2013;Vinod et al 2014;Ravi et al 2013;Kathiravan et al 2014;Raju et al 2012;Saraschandra and Sivakumar 2014;Rajakumar and Abdul Rahuman 2011;Namita and Soam 2014). Biological/green method of synthesizing silver nanoparticles uses various plants, plant parts or microorganisms to reduce silver ion to silver nanoparticles.…”