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Very Green Photosynthesis of Gold Nanoparticles by a Living Aquatic Plant: Photoreduction of Au III by the Seaweed Ulva armoricana
Author(s) -
Mukhoro Ofhani C.,
Roos Wiets D.,
Jaffer Mohammed,
Bolton John J.,
Stillman Martin J.,
Beukes Denzil R.,
Antunes Edith
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201704448
Subject(s) - colloidal gold , algae , chloroplast , green algae , photosynthesis , thallus , chemistry , catalysis , aqueous solution , nanoparticle , chlorophyta , nanotechnology , environmental chemistry , nuclear chemistry , materials science , botany , biology , organic chemistry , biochemistry , gene
Abstract Light‐assisted in vivo synthesis of gold nanoparticles (NPs) from aqueous solutions of dilute Au III salts by a living green marine seaweed ( Ulva armoricana) is reported for the first time. NPs synthesised using typical procedures have many associated environmental hazards. The reported methods involve green, nontoxic, eco‐friendly synthetic procedures. The formation of AuNPs was extremely rapid (≈15 min) following illumination of the living U. armoricana, while the rate of NP formation in the dark was very slow (over 2 weeks). The properties of the AuNPs formed were confirmed using a battery of spectroscopic techniques. U. armoricana were found to be very efficient in Au 0 uptake, and this, together with the rapid formation of AuNPs under illumination, indicated that the seaweed remained living during NP formation. The TEM images supported this, revealing that the thylakoid membranes and cell structure remained intact. The AuNPs formed on the surface of U. armoricana thallus, along the cell walls and in the chloroplasts. Without further workup, the dried, U. armoricana ‐supported AuNPs were efficient in the catalytic reduction of 4‐nitrophenol, demonstrating the completely green cycle of AuNP formation and catalytic activity. The results mean that an aquatic plant growing in water rich in gold salts could bio‐accumulate AuNPs from its aquatic environment, simply with the activation of sunlight.