Removal of Toxic 2, 4-Dinitrophenol (2, 4-DNP) and 2, 4, 6-Trinitrophenol (2, 4, 6-TNP) through Adsorptive Interaction with Metal Ferrocyanides

Antimony, cadmium and zirconium hexacyanoferrates (II) were synthesized and characterized by
elemental and spectral studies. Interaction of 2, 4-dinitrophenol (2, 4-DNP) and 2, 4, 6-trinitrophenol
(2, 4, 6-TNP) with antimony, cadmium and zirconium hexacyanoferrates (II) have been studied at
neutral pH (7.00 ± 0.01) and a temperature of 30 ± 1°C. The progress of adsorption was followed
spectrophotometrically by measuring the absorbance of substituted phenols at their corresponding
λmax. The nature of adsorption has been interpreted from the shape of adsorption isotherms. The
Langmuir type of adsorption is followed in the concentration range of 10-3 – 10-4 M of 2, 4-DNP and 2,
4, 6-TNP solutions. The 2, 4, 6 -TNP was found to have greater affinity for the antimony, cadmium
and zirconium hexacyanoferrates (II) than 2, 4 – DNP. High adsorption capacity has been observed
for cadmium hexacyanoferrate (II) while it is minimum with zirconium hexacyanoferrate (II), which
indicate highly porous characteristics of cadmium hexacyanoferrate (II) in comparison to other metal
hexacyanoferrates (II) studied. Removal of toxic phenol is necessary for the protection of our
environment. Phenols react with soil to reduce their fertility therefore its removal from soil is also
important for our food security. The p-nitrophenol was found to have greater affinity for the antimony,
cadmium and zirconium ferrocyanides than the p-aminophenol. The adsorption of 2, 4-DNP and 2,
4,6- TNP on copper, zinc, molybdenum and chromium ferrocyanides was studied at different pH and
temperature. The thermodynamic parameters for adsorption od 2, 4- DNP and 2, 4, 6- TNP on metal
ferrocyanides is reported.