The Potential Use of Low-Grade Phosphate Rocks as Adsorbent

摘要

This study evaluates the suitability of using low-grade phosphate for Cu~(2+) removal. The study also investigates the effects of the presence of ethylene-diamine-tetra-acetic acid (EDTA), eitric acid, tartaric acid and sodium chloride in a solution containing Cu~(2+) on the adsorption capacity of Cu~(2+) onto low-grade phosphate. For aqueous solutions with 100 ppm Cu~(2+), the percentage removal of Cu~(2+) 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 Cu~(2+), Cu-NaCl, Cu-tartaric acid, Cu-EDTA, or Cu-citric acid aqueous solutions, the present work shows trend of the percentage removal of Cu~(2+) at equilibrium time: Cu~(2+) > 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 Cu~(2+) significantly. This means that the adsorption capacity is ligand type and concentration dependent.