%0 Journal Article %1 Pettine1998 %A Pettine, M. %A Barra, I. %A Campanella, L. %A Millero, F. J. %D 1998 %J WATER RESEARCH %K H2S KINETICS; MEDIA; OXIDATION; SEAWATER; SPECIATION; %N 9 %P 2807--2813 %T Effect of metals on the reduction of chromium (VI) with hydrogen sulfide %V 32 %X The influence of an extended set of metals (Ca2+, Mg2+, Pb2+, Cu2+, Cd2+ Ni2+, Zn2+ Mn2+, Fe3+) on the reduction rates of chromium (VI) with H2S have been measured in NaCl solutions. Ca2+ and Zn2+ (0.01 to 0.02 M and 0.5 to 3.0 mu M) did not show any significant effect. Mg2+ and Mn2+ (0.05 to 0.2 M and 1.8 to 14.2 mu M) produced only moderate increases in the rates in 0.5 M NaCl that were not proportional to the metal concentrations. The metals studied (Pb2+, Cu2+, Cd2+ Ni2+) caused large increases in the reduction rates at micromolar concentrations. The effect was attributed to the formation of MeCrO4 complexes which react faster with sulfide than free chromate. From measurements of the rates as a function of the added metal the rate constants for the metal chromate complexes were determined. The rates increased in the order k(NiCrO4)>k(PbCrO4)>(CuCrO4)>k(CdCrO4). The addition of Fe(III) (0.2 to 1.8 mu M) increased the rates considerably due to the catalytic cycling of the redox reactions of iron. (C) 1998 Elsevier Science Ltd. All rights reserved.

@article{Pettine1998, abstract = {The influence of an extended set of metals (Ca2+, Mg2+, Pb2+, Cu2+, Cd2+ Ni2+, Zn2+ Mn2+, Fe3+) on the reduction rates of chromium (VI) with H2S have been measured in NaCl solutions. Ca2+ and Zn2+ (0.01 to 0.02 M and 0.5 to 3.0 mu M) did not show any significant effect. Mg2+ and Mn2+ (0.05 to 0.2 M and 1.8 to 14.2 mu M) produced only moderate increases in the rates in 0.5 M NaCl that were not proportional to the metal concentrations. The metals studied (Pb2+, Cu2+, Cd2+ Ni2+) caused large increases in the reduction rates at micromolar concentrations. The effect was attributed to the formation of MeCrO4 complexes which react faster with sulfide than free chromate. From measurements of the rates as a function of the added metal the rate constants for the metal chromate complexes were determined. The rates increased in the order k(NiCrO4)>k(PbCrO4)>(CuCrO4)>k(CdCrO4). The addition of Fe(III) (0.2 to 1.8 mu M) increased the rates considerably due to the catalytic cycling of the redox reactions of iron. (C) 1998 Elsevier Science Ltd. All rights reserved.}, added-at = {2009-11-03T20:21:25.000+0100}, author = {Pettine, M. and Barra, I. and Campanella, L. and Millero, F. J.}, biburl = {https://www.bibsonomy.org/bibtex/280f96d9414cce1e1c908a080a2236b0c/svance}, citedreferences = {*AM PUBL HLTH ASS, 1985, STAND METH EX WAT WA, P201 ; ELDERFIELD H, 1970, EARTH PLANET SC LETT, V9, P10 ; EMERSON S, 1979, DEEP SEA RES A, V26, P859 ; ESPENSON JH, 1963, J AM CHEM SOC, V85, P3328 ; HERSHEY JP, 1988, GEOCHIM COSMOCHIM AC, V52, P2047 ; KIEBER RJ, 1992, ENVIRON SCI TECHNOL, V26, P307 ; MILLERO FJ, 1987, GEOCHIM COSMOCHIM AC, V51, P707 ; PETTERSSON C, 1988, TRENDS ANAL CHEM, V7, P209 ; PETTINE M, 1990, LIMNOL OCEANOGR, V35, P730 ; PETTINE M, 1991, MAR CHEM, V34, P29 ; PETTINE M, 1994, MAR CHEM, V46, P335 ; SALEH FY, 1989, SCI TOTAL ENVIRON, V86, P25 ; STUMM W, 1981, AQUAT CHEM, P656 ; VAZQUEZ F, 1989, GEOPHYS RES LETT, V16, P1363 ; YAO WS, 1996, MAR CHEM, V52, P1}, interhash = {2d6b09b288d29e214e66dc44eeb8fd6d}, intrahash = {80f96d9414cce1e1c908a080a2236b0c}, journal = {WATER RESEARCH}, keywords = {H2S KINETICS; MEDIA; OXIDATION; SEAWATER; SPECIATION;}, number = 9, owner = {svance}, pages = {2807--2813}, timestamp = {2009-11-03T20:22:10.000+0100}, title = {Effect of metals on the reduction of chromium (VI) with hydrogen sulfide}, volume = 32, year = 1998 }