(Merck) solution (0.25%) in 50% acetone was prepared.
Though some other reagents such as dithizone, diphenylcarbazide
, di-2-pyridylketone benzoylhydrazone , and 3-butan-2-oneoxime  have sensitive, these reagents are time consuming, requiring labor intensive and consuming large quantity of organic solvents.
From the mentioned studies, it is obvious that Cr(VI) has a high affinity for amine functional groups, and it is this narrative that led to the present study where Macadamia nutshells were functionalized, for the first time, with 1,5'diphenylcarbazide
for the eradication of hexavalent chromium from aqueous solution.
The effluent containing Cr(VI) ions was taken away with diphenylcarbazide
as masking agent creates the reddish purple color in the solution.
The photocatalyst was centrifugally separated (9500 rpm, 2 min), and the Cr(VI) concentration was determined by diphenylcarbazide
Cr(VI) was analysed by diphenylcarbazide
method, and Cd(II) by dithizone method.
Khorasani-Motlagh, "Specific extraction of chromium as tetrabutylammonium-chromate and spectrophotometric determination by diphenylcarbazide
: speciation of chromium in effluent streams," Analytical Sciences, vol.
spectrophotometrically at 540 nm using diphenylcarbazide
as the complexion agent (Rand et al.
Adsorption Experiments: Estimation of Chromium by Diphenylcarbazide
After adsorption equilibrium was achieved, aqueous phase was separated by centrifuging (at 5000 rpm), and equilibrium concentration of U(VI) complex with arsenazo III was determined in a strongly acidic medium (5 M HN[O.sub.3]); concentration of Cr(VI) complex with diphenylcarbazide
was determined by spectrophotometry [11,12], and concentration of heavy metals was determined by using C-115-M1 atomic absorption spectrophotometer at the wavelength of [lambda] = 232.0 nm for Ni(II), [lambda] = 240.7 nm for Co(II), [lambda] = 283.3 nm for Pb(II), and [lambda] = 324.7 nm for Cu(II).
The concentration of Cr(VI) was determined using diphenylcarbazide
colorimetric method at a wavelength of 540nm.
Reduction of hexavalent chromium by bacteria In order to determine the ability of bacterial isolates to reduce Cr6+ (100 ug/ml) to Cr3+, diphenylcarbazide
method was used (Fulladosa et al., 2006).