© by PSP Volume 27 ｱ No. 11/2018 pages 7332-7339 Fresenius Environmental Bulletin 7332 IRON LOADED SPHERICAL MESOPOROUS SILICA PARTICLES FOR DECHLORINATION OF TRICHLOROETHYLENE IN WATER Afshan Urooj 1,* , Saima Nasreen 2 , Uzaira Rafique 3 , Ryan Felix 4 , Yujia Liang 4 , Sheryl Ehrman 4,5 1 Department of Environmental Sciences, GC Women University Sialkot, Kuchery Road, Sialkot, Pakistan 2 Department of Environmental Sciences, Women University Multan, Kuchery Chowk, Multan, Pakistan 3 Department of Environmental Sciences, Fatima Jinnah Women University, The Mall, Rawalpindi 46000, Pakistan 4 Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA 5 Charles W. Davidson College of Engineering, San Jose State University, San Jose, CA 95192, USA ABSTRACT Iron loaded spherical mesoporous silica parti- cles were synthesized to prevent agglomeration of iron particles. By carrying out sol-gel process in presence of dissolved ferric salt and subsequent re- duction of the obtained particles yielded zero valent iron loaded spherical mesoporous silica particles. The results indicated that mean diameter of the par- ticles reduced from 627 nm to 229 nm on increasing the iron content from 0.00 mmol to 1.25 mmol, de- picting an inverse relationship between the particle size and molar ratio of the iron salt. The surface area analysis at lower iron loading revealed surface area of the particles significantly high (417 m 2 /g). In batch experiments, the synthesized particles success- fully removed 95% of trichloroethylene in short du- ration (60 min). The results of this study illustrate the potential use of iron loaded spherical mesoporous silica particles for dechlorination of chlorinated or- ganic compounds in underground waters and con- taminated soil. KEYWORDS: Mesoporous Silica, Dechlorination, Trichloroethylene, Sol-Gel INTRODUCTION Chlorinated organic compounds have been widely introduced in environment due to human and industrial activities [1]. Trichloroethylene (TCE) is among the most prevalent pollutants present in envi- ronment [2]. TCE has been linked with occurrence of skin rashes, liver problems, hearing impairments, liver problems, blood and urinary tract disorders and different forms of cancer [3, 4]. Therefore, serious and immediate coordinated efforts are required at global scale to address the environmental challenge [5]. Among different methods and techniques to re- move TCE from the environment, zero valent iron (ZVI) particles to reductively dechlorinate the pollutant has been of particular interest [6, 7]. Mainly due to low toxicity of iron, ZVI particles has been studied for dechlorination of the contaminant from ground water [8-10]. Iron in its zero valent state act as reducing agent and donate electrons for reduc- tive dechlorination of the chlorinated contaminant, and converts it to non-halogenated products and chloride irons [11]. Due to rapid dechlorination and convenient application, ZVI particles has been shown to effectively treat underground water [12, 13]. Nano sized zero valent iron (nZVI) particles of- fer higher surface area and have shown improved dechlorination compared to microscale ZVI [12, 11]. It is well known fact that nanoparticles tend to ag- glomerate due to interactions between colloidal na- noparticles and increased surface to volume ratio. Therefore, this results in a challenging task to stabi- lize colloidal particles by avoiding agglomeration, otherwise agglomeration results in loss of peculiar properties that are displayed at nano-scale [14]. Mes- oporous silica is a good candidate to be used as sup- port material for nanoparticles due to its high surface area (~500-1000 m 2 /g) and desirable pore size (2-50 nm), thus having potential to stabilize the nanoparti- cles while maintaining their high activity [15]. The present study focuses on synthesis and characteriza- tion of iron loaded spherical mesoporous silica par- ticles (Fe-SMSPs) and their demonstration for dechlorination of trichloroethylene in water. MATERIALS AND METHODS Chemicals and materials. Hexadecyltrime- thylammonium bromide (CTAB) 98%, tetraethyl or- thosilicate (TEOS) 98%, ethanol (absolute, anhy- drous), 28-30 % ammonia, iron (III) nitrate nonahy- drate 99.9%, n-hexane 95%, trichloroethylene (TCE) 99.5% and sodium borohydride 99% were purchased from Sigma-Aldrich. Deionized water (18.2 0FP ZDV REWDLned from a MilliQ water purifica- tion system. Procedures. For synthesis of SMSPs, the mo- lar ratio of the reagents TEOS:CTAB:NH3: