Ž . Journal of Hazardous Materials B70 1999 117–138 www.elsevier.nlrlocaterjhazmat Immobilization of phenol in cement-based solidifiedrstabilized hazardous wastes using regenerated activated carbon: leaching studies Vikram M. Hebatpuria a , Hassan A. Arafat b , Hong Sang Rho c , Paul L. Bishop a, ) , Neville G. Pinto b , Relva C. Buchanan c a Department of CiÕil and EnÕironmental Engineering, UniÕersity of Cincinnati, PO Box 210071, Cincinnati, OH 45221, USA b Department of Chemical Engineering, UniÕersity of Cincinnati, Cincinnati, OH 45221, USA c Department of Material Science and Engineering, UniÕersity of Cincinnati, Cincinnati, OH 45221, USA Received 20 November 1998; received in revised form 25 May 1999; accepted 26 May 1999 Abstract In this research, we investigated the use of an inexpensive thermally regenerated activated carbon as a pre-adsorbent in the solidificationrstabilization of phenol-contaminated sand. Our Ž results show that even the addition of very low amounts of regenerated activated carbon 1%–2% . wrw sand resulted in the rapid adsorption of phenol in the Chemical solidificationrstabilization Ž . SrS matrix, with phenol leaching reduced by as much as 600%. Adsorption studies indicated that the adsorption of phenol on the reactivated carbon was found to be partially irreversible over time in the SrS waste form, indicating possible chemical adsorption. Pore-fluid analyses of the cement paste containing phenol suggested the formation of a calcium–phenol complex, which further reduced the amount of free phenol present in the pores. Studies using several micro-struct- ural techniques, including field emission scanning electron microscopy, X-ray diffraction, fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy, indicated significant morphological changes in the cement matrix upon the addition of phenol and reactivated carbon. The hydration of cement in the presence of phenol was retarded concomitant with formation of amorphous portlandite. q 1999 Elsevier Science B.V. All rights reserved. Keywords: Solidificationrstabilization; Organics; Activated carbon; Scanning electron microscopy; Infra-red spectroscopy ) Corresponding author. Tel.: q1-513-556-3675; fax: q1-513-556-2599; e-mail: paul.bishop@uc.edu 0304-3894r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S0304-3894 99 00128-4