Author
 |
Lima, Isabel |
|
Marshall, Wayne |
|
Submitted to: Journal of Chemical Technology & Biotechnology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/25/2005 Publication Date: 8/30/2005 Citation: Lima, I.M. and Marshall, W.E. 2005. Adsorption of select environmentally important metals by poultry manure-based granular activated carbons. Journal of Chemical Technology and Biotechnology. 80(9):1054-1061. Interpretive Summary: Water quality and public health impacts of poultry manure produced at large concentrated animal facilities have prompted the need for viable solutions for their conversion and reuse. The conversion of poultry manure to value-added activated carbons for environmental remediation can be such a solution. The objective of this study was to compare the effectiveness of poultry manure-based granular activated carbons for the adsorption of select metal ions individually and in a competition mode. The carbon's ability to adsorb the metals was influenced by the activation strategy, increasing for longer activation times and higher water flow rates. Manure-based carbons outperformed coal, coconut shell and wood-based carbons as well as the commercial carbon PUR RF; and with the exception of Ni2+ manure-based carbons also outperformed the commercial carbon Minotaur. Experiments showed that the highest removal rate in a competition situation was obtained for broiler cake carbon activated for 45 min at 3 ml/min, with 93.1% for copper ion, 50.9% for cadmium ion, and 85.2% for zinc ion. The manure-based carbons appear to be promising as potentially inexpensive sources of carbon for adsorbing selected metal ions. Technical Abstract: Water quality and public health impacts of poultry manure produced at large concentrated animal facilities have prompted the need for viable solutions for their conversion and reuse. The conversion of poultry manure to value-added activated carbons for environmental remediation can be such a solution. The objective of this study was to compare the effectiveness of poultry manure-based granular activated carbons for the adsorption of select metal ions (copper, cadmium, nickel, zinc) from solutions containing either individual ions at 5 and 20 mM concentrations or the four metal ions present together at 5 mM concentrations for each ion. Adsorption properties for manure-based carbons were compared to the adsorption properties of two commercial carbons and carbons from three "traditional" carbon precursors, namely, coal, coconut and wood. Pelletized manure samples and common carbon precursors were pyrolyzed at 700°C for 1 hr followed by activation in an inert atmosphere under steam at 1, 3 and 5 ml/min water flow rate, for 30 and 45 min, under nitrogen. The carbon's ability to adsorb the metals was influenced by the activation strategy, increasing for longer activation times and higher water flow rates. Saturation conditions were achieved at 20 mM and, at 5 mM almost all metal ion in solution was adsorbed, with the exception of nickel. Competition studies were carried out by exposing activated carbons to a solution containing a set of four metals (Cd2+, Cu2+, Ni2+, and Zn2+). With a few exceptions, the carbon showed similar affinity towards copper, cadmium and zinc, individually. However, when all metals were present in solution, manure based carbons showed a preference for Cu2+ followed by Zn2+ and Cd2+. Manure-based carbons outperformed coal, coconut shell and wood based carbons as well as the commercial carbon P'R RF; and with the exception of Ni2+ manure-based carbons also outperformed the commercial carbon Minotaur. Experiments showed that the highest removal rate in a competition situation was obtained for broiler cake carbon activated for 45 min at 3 ml/min, with 93.1% for copper ion, 50.9% for cadmium ion, and 85.2% for zinc ion. The manure-based carbons appear to be promising as potentially inexpensive sources of carbon for adsorbing selected metal ions. |
