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Biosynthesis of silver nanoparticles (AgNPs) from seaweed extracts is currently under exploitation. Seaweed extracts are cost effective and eco-friendly and thus can be an economic and efficient alternative for large-scale synthesis of nanoparticles. The present study reports the synthesis of AgNPs from silver precursor, silver nitrate using aqueous extract of seaweed Gracilaria corticata ( G. corticata ). The organic compounds present in the filtrate of G. corticata were mainly responsible for reduction of silver ions to AgNPs. The filtrate when added to 1 mM aqueous silver nitrate solution at 121°C changed to dark brown colour solution within ten minutes, which confirms the bioreduction. These extremely stable AgNPs were characterised by UV-Vis spectrophotometer, FTIR, XRD, TEM, and EDS analysis. The nanoparticles exhibited maximum absorbance at 424 nm in the UV spectrum. The presence of proteins was identified by FTIR. TEM micrograph revealed the formation of polydispersed and spherical shaped nanoparticles with the size range of 10–50 nm and the presence of elemental silver were confirmed by EDS analysis. These nanoparticles showed cytotoxic activity against Hep2 cells.

Antimony, in both its trivalent and pentavalent states may be detrimental to the electrochemical deposition of zinc. Ideally, therefore antimony should be monitored in both oxidation states throughout an electrolytic zinc plant. At hydrochloric acid concentrations ( > 4 M) both antimony(III) and (V) present in zinc plant electrolyte can be reduced at a hanging mercury drop electrode (HMDE) to form an antimony amalgam, Sb(Hg). Consequently a very sensitive analytical signal is obtained for the determination of total antimony by differential pulse anodic stripping voltammetry (DPASV) using a 1:1 mixture of plant electrolyte and concentrated hydrochloric acid. In contrast, at low acid concentrations (0.1 M) predominantly only antimony(III) can be reduced and therefore determined in zinc plant electrolyte by DPASV at a HMDE by use of a 1:1 mixture of plant electrolyte and 0.2 M hydrochloric acid. The antimony(V) concentration is calculated by the method of subtraction of antimony(III) from total antimony. Consequently, simple addition of high and low concentrations of hydrochloric acid to zinc plant electrolyte can be used to provide a suitable electrolyte for both off‐line and on‐line methods for determining the concentration of total antimony, antimony(III) and antimony(V). The method described in this article has been applied to a wide range of zinc electrolyte samples and an on‐stream analyzer technique has been successfully used for several years at the Pasminco Metals‐BHAS electrolytic zinc plant in Port Pirrie, Australia.