Submitted to: Waste and Biomass Valorization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/2013
Publication Date: 8/1/2014
Citation: Fitzmorris, K.F., Lima, I.M., Marshall, W.E. 2014. Cation and anion release from broiler litter and cake activated carbons and the role of released anions in copper ion uptake. Waste and Biomass Valorization. 5(4):689-697.
Interpretive Summary: The importance of removing toxic metals from water sources has increased over the last ten years due to the link established between the presence of these metals and negative health effects. We have in the past evaluated the capabilities of activated carbons made from poultry manure to absorb select metals. The next step is finding the mechanism that enables these carbons to adsorb metals. In this study, we placed the carbons in acid solutions to remove the ash particles and any other negative species. We then tested the acid solution to determine what was removed. We also tested this carbon that had been washed with the acid to determine if its ability to adsorb copper had changed. Our results showed that we removed a large amount of calcium, magnesium, and phosphorus, and of these we believe phosphorus to be the most important. We also noted the carbon’s ability to remove copper from solution was significantly decreased by this acid washing procedure. The release of phosphorus and also sulfur from the carbons corresponded with the amount of copper adsorbed. Since the presence of phosphorus was about 10 times greater than of sulfur, phosphorus as phosphate was most likely involved in the binding of copper. These results show a potential benefit for the phosphorus found in the poultry manure which is currently only a liability.
Technical Abstract: The development of activated carbons from broiler litter and broiler cake results in a large ash fraction that can be removed by acid treatment. The primary use for these carbons is in the removal of metal cations from aqueous solution. The objectives of this study were 1) to determine the extent that select cations (calcium, copper, iron, magnesium and zinc) and select anions (phosphorus and sulfur) were released from litter and cake carbons under conditions of varying acid strength, and 2) to determine which of the elements in the ash fraction may contribute to metal (copper) ion binding. In order to accomplish this, both litter and cake activated carbons were placed in solutions of hydrochloric acid at concentrations of 0.05M, 0.1M, 0.5M, 1.0M and 2.0M for 30 minutes to 4 hours. The resulting solutions were analyzed for the release of the seven select cations and anions. Calcium, phosphorus and magnesium were present in the greatest concentration. Of these seven species, phosphorus and sulfur were of particular interest due to their potential for binding copper ions. The release of phosphorus and sulfur from the carbons corresponded with the amount of copper adsorbed. Since the presence of phosphorus was about 10 times greater than of sulfur, phosphorus as the anion, presumably phosphate was most likely involved in copper ion binding.