Ws. Rader et al., PHOTOCHEMISTRY OF AQUEOUS-SOLUTIONS OF DICYANOMERCURY(II) AND POTASSIUM TETRACYANOMERCURATE(II), Journal of solar energy engineering, 116(3), 1994, pp. 125-129
Photochemically induced reactions of dicyanomercury(II) and potassium
tetracyanomercurate(II) in alkaline aqueous solutions were investigate
d in detail. The studies were conducted in the presence or absence of
a titanium (IV) oxide semiconductor photocatalyst utilizing sunlight a
s the irradiation source. It was established that the cyanide ion libe
rated from the thermodynamically stable mercury-cyano species can be p
hotocatalytically oxidized via cyanate and nitrite to nitrate. In addi
tion, the process removes over 99 mol% of mercury from the solution. I
n the absence of the photocatalyst, no photoproducts were detected and
mercury remained in solution. The results obtained may have ramificat
ions for the use of solar power for the efficient treatment of large q
uantities of precious metals mill tailings wastes containing various c
yanide species. In addition, in order to follow the fate of cyanide in
these experiments, a novel gas-diffusion flow injection analysis syst
em for the determination of cyanide from the thermodynamically stable
mercury-cyano complexes was utilized.