Adsorption of selected environmentally important metals by poultry manure‐based granular activated carbons

Water quality and public health impacts of mass produced poultry manure have prompted the need for viable conversion and reuse solutions. Conversion of poultry manure to value‐added granular activated carbons for environmental remediation can be such a solution. The objective of this study was to compare the effectiveness of poultry manure‐based carbons for the adsorption of selected metal ions (copper, cadmium, nickel, zinc) from solutions containing individual ions or the four metal ions present together. Adsorption properties for poultry manure‐based carbons were compared with those of two commercial carbons, PūR RF and Minotaur, and carbons from three traditional precursors, coal, coconut and wood. Pelletized samples were pyrolyzed at 700 °C for 1 h followed by 800 °C steam activation at 1, 3 and 5 mL min^?1 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, in the presence of a single metal solution. Saturation conditions were achieved at 20 mM and, at 5 mM , almost all metal ion in solution was adsorbed, except for nickel. Carbons showed similar affinity towards copper, cadmium and zinc, individually. However, when in competition, at 5 mM of each metal, manure‐based carbons showed a preference for Cu²⁺ followed by Zn²⁺ and Cd²⁺. Poultry manure‐based carbons outperformed all reference carbons and PūR RF, and, except for Ni²⁺, Minotaur was also outperformed. 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^?1, with 93.1%, 50.9% and 85.2% for copper, cadmium and zinc ions, respectively. Published in 2005 for SCI by John Wiley & Sons, Ltd.