Synthesis of Silver Nanoparticles Using o-Hydroxybenzoic, p-Hydroxybenzoic, and o,p-Dihydroxybenzoic Acids as Reducing Agents

Abstract

Synthesis of silver nanoparticles (AgNPs) by reduction of AgNO3 with o-hydroxybenzoic, p-hydroxybenzoic and o,p-dihydroxybenzoic acids as reducing agents was investigated. This research was conducted to determine the effect of the position and number of hydroxyl groups towards the size, shape and stability of the resulted AgNPs. Surface Plasmon Resonance (SPR) of AgNPs was characterized by UV/Vis spectrophotometer, the shape and size of AgNPs was determined by Transmission Electron Microscope (TEM). The results showed that the reducing agent that has substituents in the para position (p-hydroxybenzoic acid) has the higher reduction ability than the others. AgNPs were yielded by all types of reducing agents in alkaline system. Reducing agents which have greater number of substituents (o,p-dihydroxybenzoic acid) could produce AgNPs with smaller concentration of AgNO3 than the others. AgNPs that was produced by reducing agent having substituents on the para position (p-hydroxybenzoic acid) was more stable and smaller particle size, i.e. 34 ± 1.78 nm than reducing agent that has substituent on the ortho para positions (with particle size 45 + 3.67 nm) and ortho positions (with particle size 70 ± 4.96 nm).

The Performance of p-Aminosalicylic Acid As Reducing and Stabilizing Agent in Silver Nanoparticles Synthesis

“…The average particle sizes counted from the TEM image are 14.55±7.13 nm. Compared to the previous study, AgNPs synthesized using p-aminosalicylic acid has smaller size compared with AgNPs synthesized by using hydroxybenzoic acid 16,17 and dihydroxybenzoic acid 18 . However, AgNPs in this research are still not uniform, some particles stick to each other because the reduction process had not finished and kept going on even under room condition.…”

“…The same optimum pH was also obtained for several reducing agents, which are the derivatives of the benzoic acid, such as hydroxybenzoic acid 16,17 , dihydroxybenzoi acid 18 , and aminobenzoic acid 21 . The synthesis of AgNPs by using derivatives of benzoic acid is usually conducted under basic conditions.…”

“…The same mole ratio was also used by Susanthy et al, (2017) which used dihydroxybenzoic acid as reducing and stabilizing agent in AgNPs synthesis 18 . But this result was a little bit different with the effective mole ratio of AgNO 3 to the p-hydroxybenzoic acid which has value 1:20 16 .…”

“…both reducing and stabilizing agent is preferable than using two different chemicals. Some previous study had been conducted by using benzoic acid derivatives with hydroxy phenolic group as reducing and stabilizing agent in the AgNPs synthesis 16,17,18 . However, the use of benzoic acid derivatives with amino and hydroxyl phenolic groups has not been performed yet.…”

Synthesis of Gold Nanoparticles Using <i>p</i>-Aminobenzoic Acid and <i>p</i>-Aminosalicylic Acid as Reducing Agent

“…Hydroxyl group and an amino group in reducing agent acted as the lone pair electron donor for gold ion, especially Au 3+ . The presence of hydroxyl group in reducing agent can give more lone pair electron to the gold ion, so it can react more easily with gold ion [23]. Therefore, apart from the amino group, hydroxyl group in p-aminosalicylic acid could also enhance the reduction ability of this reducing agent.…”