Green chemistry approach for the synthesis of gold nanoparticles with gum kondagogu: characterization, catalytic and antibacterial activity

Abstract

Gold nanoparticles (AuNPs) were prepared from HAuCl 4 using gum kondagogu, by adopting green synthesis, which is a simple, low cost and ecofriendly technique. The gum kondagogu (Cochlospermum gossypium) serves as both reducing agent and stabilizer. The formation of the AuNPs was identified through the change in the color of the solution from yellow to red. The synthesized AuNPs were characterized by various techniques. The green synthesized AuNPs were found to be stable in the pH range pH 2-12 and up to the concentration of 5 M NaCl. The stabilized AuNPs demonstrated the excellent catalytic activity in reducing p-nitrophenol to p-aminophenol in the presence of a reducing agent, NaBH 4 . The effects of catalyst dose and temperature were studied. The synthesized, new gum-based catalyst was very efficient, easy to prepare, stable, cost-effective and ecofriendly. The synthesized AuNPs showed good antibacterial activity.

Microwave-irradiated green synthesis of gold nanoparticles for catalytic and anti-bacterial activity

“…Figure 1 shows the role of papaya leaf extract concentration on the formation of AuNPs, studied by microwaving the different concentrations (0.1 to 1%) of papaya leaf extract containing 1 mM of HAuCl 4 for 2 min of time. With an increase in the concentration of papaya leaf extract, there is an enhancement in the concentration of AuNPs (Reddy et al 2015b). Figure 2 shows the synthesis of nanoparticles by changing the concentration of HAuCl 4 and the reduction was studied with 1% papaya leaf extract.…”

“…Several biological systems such as fruit extract, fungi, plants and bacteria can actively reduce metal ions to form metal nanoparticles in environmentally friendly conditions. Recently, green syntheses of gold nanoparticles by using Zizyphus mauritiana extract, palm oil mill effluent, enzymes, garlic extract, gum kondagogu and acacia nilotica are reported (Gan et al 2012;WhiteII et al 2012;Adelere and Lateef 2016;Reddy et al 2015b;Majumdar et al 2013).…”

Microwave-assisted synthesis of silver nanoparticles and their application in catalytic, antibacterial and antioxidant activities

“…After the addition of AgNPs, the intensity decrease was monitored using UV-Vis spectrophotometer. The electron transfer reaction was performed at different temperatures between 30 and 70 °C [36,45].…”

“…We also examined the effect of concentration of AgNO 3 for the synthesis of AgNPs by keeping the concentration of CMGK (0.5%) constant. Figure 1b clearly suggested that with increase of AgNO 3 concentration, more and more number of Ag + ions become available in the solution, which further reduced and effectively capped by CMGK molecules to produce more number of AgNPs [36,39,46,47].…”

“…It is a broadly utilized alteration technique in light of its simplicity of handling, bring down cost of chemicals and versatility of the product obtained. Many natural gums such as Cassia tora gum, gellan, guar gum, and gum karaya were investigated using the carboxymethylation process [34][35][36][37].…”