Chemical Engineering & Technology, Vol.25, No.9, 921-924, 2002
The potential use of low-grade phosphate rocks as adsorbent
This study evaluates the suitability of using low-grade phosphate for Cu2+ removal. The study also investigates the effects of the presence of ethylene-diamine-tetra-acetic acid (EDTA), citric acid, tartaric acid and sodium chloride in a solution containing u on the adsorption capacity of Cu onto low-grade phosphate. For aqueous solutions with 100 ppm Cu, the percentage removal of Cu2+ at pH 4 onto 0.2 g of 0.063 mm low-grade phosphate was found to be 96.6% after one hour. Using one mmol of either Cu2+, Cu-NaCl, Cu-tartaric acid, Cu-EDTA, or Cu-citric acid aqueous solutions, the present work shows trend of the percentage removal of Cu2+ at equilibrium time: Cu2+ > Cu-NaCl > Cu-tartaric acid > Cu-EDTA > Cu-citric acid. It is also found that increasing the concentration of ligand to copper ratio decreases the percentage removal of Cu2+ significantly. This means that the adsorption capacity is ligand type and concentration dependent.