The press-cake (PC) of oleaginous species (Brassica napus, Moringa oleifera, Glycine max) has been investigated as a biosorbent for metals removal from contaminated water.
Sorption isotherms for copper (Cu) have been established for different pH values and fitted with Langmuir isotherms. The maximum sorption capacity was observed at pH 5 (qmax=11.5 mg/g). The press-cake has been fractionated into water- soluble components, husks and the remaining solid residue. From these fractions the husks are responsible for the largest part of the sorption activity (qmax=36.6 mg/g). The sorption mechanism was shown to be complex, involving proton exchange, chemisorption and calcium exchange. FTIR experiments showed that hydroxyl groups are involved in the metal binding.
The findings show that in the removal of toxic metals, the use of oleaginous seed by-products represent a low cost, domestic and environmentally friendly technology, from which the metals, in concentrated form, may be readily recovered.