Photobiological synthesis of noble metal nanoparticles using Hydrocotyle asiatica and application as catalyst for the photodegradation of cationic dyes

Abstract

Solar light induced photo catalysis by plasmonic nanoparticles such as Au and Ag is an important field in green chemistry. In this study an environmental benign method was investigated for the rapid synthesis of colloidal Ag and AuNPs using the extract of Hydrocotyle asiatica, as a reducing and stabilizing agent under sunlight irradiation. The nanoparticles were formed in few seconds and were characterized by UV-Vis., FT-IR, TEM, EDAX, XRD, DLS and Zetasizer. The nanoparticles were stable in aqueous solution for more than 6 months. TEM analysis established that the Ag and AuNPs were predominantly spherical with average size of 21 and 8 nm, respectively. The flavonoids and glycosides from the extract of H. asiatica were proved to be responsible for the reduction and capping through FT-IR analysis. The antimicrobial studies of AgNPs showed effective inhibitory activity against the clinical strains of gram-negative and positive bacteria. The localized surface plasmon resonance of AgNPs was used for the photo-driven degradation of cationic dyes (malachite green and methylene blue). Thus, this green technique can be used for bulk production of AgNPs, and thus prepared nanoparticles may be used for removal of dyes from effluent. Graphical Abstract

Rapid Green Synthesis of Silver Nanoparticles (AgNPs) Using (Prunus persica) Plants extract: Exploring its Antimicrobial and Catalytic Activities

“…It was found that the adsorption rate is rapid at the initial stages (Figure 8) because of the high vacant site to adsorb heavy metal and the system reaches equilibrium after 120 min and 150 min respectively. After equilibrium time, removal process became slow because of pore diffusion or saturation of adsorbent with heavy metals [5][6][7]. The degree of removal was very high for heavy metal by using AgNPs, more than 80% of Cd and Pd removal was achieved in 120 and 150 min respectively and after equilibrium time, the removal rate became slow [9].…”

“…Recently, a simple and eco-friendly green approach for synthesis of silver nanoparticles by various plant extracts have drawn the attention of academician and researcher because of its advantage over physical and chemical methods [4][5][6][7][8][9][10][11][12]. Synthesis of nanoparticles by green approach is emerging field because of its various advantages over the other process like nontoxic, ecofriendly and low cost.…”

“…Antibacterial activity was performed against all the two bacterial strains as per guidelines by Clinical and Laboratory Standards Institute (CLSI, M02-A12). These were grown overnight and diluted in Mueller-Hinton broth (MHB) to a cell density of 10 5 Colony Forming Unit (CFU)/mL. 100 µl of this culture was spread on the Mueller-Hinton Agar (MHA) plate and allowed to dry in a sterile condition.…”

Antioxidant, antimicrobial and cytotoxic activities of silver and gold nanoparticles synthesized using Plumbago zeylanica bark

“…Different fungi like Fusarium oxysporum [10], Cladosporium cladosporioides [11], Fusarium semitactum [12], plants like Syzygium aromaticum [13], Medicago sativa [14], Azadirachta indica [15], Terminalia cuneata [16], and Trignellafoenum graecum seeds [17] have been employed to synthesize metal nanoparticles. Recently, sunlight-induced rapid synthesis of silver nanoparticles has been reported by our group [18,19]. Biosynthesis of silver nanoparticles using bark of Cinnamon zeylanicum [20], Piper nigrum [21], Breynia rhamnoides [22], Avicennia marina [23], Callicarpa maingayi [24], Cissus quadrangularis [25], Artocarpus elasticus [26], and Saraca indica [27] has also been reported.…”

Eco-friendly seeded Fe3O4-Ag nanocrystals: a new type of highly efficient and low cost catalyst for methylene blue reduction

“…It is worthy to note that the calculated rate constant is much higher than those previously reported values for the degradation of MB by using semiconductor photocatalysts, [66][67][68] moreover, the rate constant for the Fe 3 O 4 -Ag seeds nanocrystals is signicantly higher than the previous works by utilizing noble metal catalysts. [69][70][71] It can been noticed that the time required to catalytic reduce decreases with the increase of the amount of silver seeds deposited on the Fe 3 O 4 surfaces. It is generally accepted that the catalytic reaction of silver nanocrystals occurs through electron transfer.…”