Alkaline Hydrolysis of TNT in Micellar System S. M. Solyman, 1 S. Shaban, 1 S. Morsy, 2 A. Y. El-Naggar, 2 A. M. Badawi, 1 and S. M. Ahmed 1 1 Egyptian Petroleum Research Institute, Nasr City, Cairo, Egypt 2 Taif University, Faculty of Science, Taif, Kingdom of Saudi Arabia The influence of micellar and Ca(OH) 2 water system on the rates of alkaline hydrolysis of 2,4,6-trinitrotoluene (TNT) was studied and evaluated quantitatively via capillary gas chromato- graphy (CGC) and high performance liquid chromatography (HPLC). The critical micelle con- centrations and rate constants of reactions in the micellar phase were determined in micellar solutions of cationic, anionic or nonionic systems. An increase in the rates of alkaline hydrolysis of TNT was observed. Alkaline hydrolysis of TNT using mixture of nonionic surfactant micelles and anionic surfactant showed higher degradation than that with a cationic surfactant. Keywords Alkaline hydrolysis, gas chromatography, high performance liquid chromatography, micellar solutions, trinitrotoluene INTRODUCTION 2,4,6-Trinitrotoluene (TNT) and its metabolites are major pollutants of soil and water encountered at mili- tary installations. TNT is the most extensively produced nitro aromatic explosives and, therefore, has been present most abundantly in the environments. [1] Due to the adverse natural receptors, [2,3] a low cost means of decon- taminating these areas of contamination is needed. Sev- eral treating methods of TNT contaminated water have been developed. Among them, carbon adsorption has often been used for the effective treatment of munitions plant wastewater. [4] However, the spent carbon constitu- tes a hazardous waste and, if allowed to dry, may also become explosive. However, spent carbon adsorption must be treated and can dramatically increase treatment costs. Bioremediation of explosives has been widely and successfully studied over the past decade. However, it is still faced with several challenges. For instance, under aerobic conditions TNT is resistant to biodegradation due to the presence of electron withdrawing nitro groups that inhibit electrophillic attack by oxygenase enzymes. [5] Batch alkaline hydrolysis has been reported to be a potential alternative remediation technology for alkaline TNT hydrolysis in the laboratory using a continuous flow stirred-tank reactor reduced TNT to 99% at pH 12 and the hydraulic retention time (HRT) of one day. A conceptual cost analysis indicated that alkaline TNT hydrolysis was more economical than granular activated carbon GAC adsorption for long treatment periods (30 years or more). [6,7] Degradation of 2,4,6-trinitrotoluene (TNT) was investigated in presence of different oxidants (Fenton’s reagent, sodium persulfate, peroxymonosulfate and potassium permanganate) and Electro-Fenton’s reagents in aqueous solution. [8,9] The effects of additives (i.e., methanol, EDTA, mannitol, thiourea, nitrous oxide, oxygen, and ozone) on gamma irradiation of TNT were investigated. [10] Treatment of munitions wastewater for the removal of TNT using various surfactant, it was decided to extend such surfactant-explosive experiments to the cyclic polynitramine explosives RDX and HMX. Results obtained with the aqueous surfactant-TNT sys- tems indicated initial formation of a TNT addition com- plex (Janovsky reaction) with a subsequent precipitation from solution of a surfactant-TNT complex salt. [11] Like- wise cationic surfactants are found to cause hydrolysis for explosives. For example, hexadecyltrimethylammo- nium bromide has been used to catalyze the hydrolysis of RDX and TNT in water. [12] Freeman [13] applied sur- factants to accelerate alkaline hydrolysis of RDX in was- tewater and reported high reaction rates at high pH values (10–12) and temperatures above 50  C. Products, reaction pathways, and the kinetics of RDX alkaline hydrolysis have been studied intensively. [14] After the complete disappearance of RDX, the hydrolysis products were identified as NO  2 ,N 2 , NH 3 ,N 2 O, HCOO  , CH 2 O, and H 2 . In our study, the alkaline hydrolysis of TNT in presence of micellar systems: anionic, cationic nonionic, and mixed surfactants were investigated. Received 10 February 2010; accepted 7 March 2010. Address correspondence to S. M. Ahmed, Egyptian Petroleum Research Institute, 1 Ahmed E-Zomor St., Nasr City, Cairo, Egypt. E-mail: saharahmed92@hotmail.com Journal of Dispersion Science and Technology, 32:731–736, 2011 Copyright # Taylor & Francis Group, LLC ISSN: 0193-2691 print=1532-2351 online DOI: 10.1080/01932691.2010.480867 731