Journal of Hazardous Materials, Vol.156, No.1-3, 156-162, 2008
Utilization of steel-making slag for the uptake of ammonium and phosphate ions from aqueous solution
Steel-making slag, a waste by-product of the Steel Industry, constitutes a major disposal problem. In the present study, excellent adsorbent materials for reducing eutrophication in wastewaters have been prepared from this slag. Heated samples of acid-treated slag and mixtures of slag with kaolinite and Al(OH)(3) were examined to determine their uptake capacities for NH4+ and PO43- from aqueous solutions. In general, the equilibrium pH of the solution increased in comparison to initial pH with the uptake of target ions, the sample activated slag-Al(OH)(3) showing the smallest change. The highest PO43-uptake capacity was obtained with the slag-Al(OH)(3) mixture heated at 900 degrees C whereas the highest uptake of NH4+ was found in the slag-Al(OH)(3) mixture heated at 800 degrees C. The uptake rates for PO43- and NH4+ by the slag-Al(OH)(3) mixture heated at 900 degrees C were 2.91 and 0.65 mu mol/(g min), respectively. It was shown that heating slag composites prior to incorporation into wastewater treatment filters resulted in an increased degree of NH4+ and PO43-uptake. (C) 2007 Elsevier B.V. All rights reserved.