Synthesis and Application of Mesoporous Silica Based Particles for Dechlorination of Trichloroehylene

Abstract

Chlorinated organic compounds are released to the environment as a result of production, use and inefficient handling of these compounds. Such compounds are highly stable, toxic toward living organisms including humans and causes cancer and other disorders. Trichloroethylene (TCE), a representative of chlorinated organic compounds is largely used in various industries and its release impacts adversely on environment. To control its damaging effects, removal and decomposition of TCE is highly desirable. The current study is focused on synthesis of novel Iron loaded spherical mesoporous silica particles (SMSPs) and its application as adsorbent for dechlorination of TCE. The silica was synthesized using modified Stöber’s method at varying temperatures (20-70 °C) to study its effect on the size and porosity of the synthesized particles. Loading of iron into silica follows two routes to carry out pre and post modification of mesoporous silica particles through sol gel and reduction process. During the synthesis, ratio of silica to Iron is varied from 1:10 to 1:5 to study its impact on loaded iron and porosity of the Iron loaded spherical mesoporous silica particles (Fe-SMSPs). The synthesized particles were characterized using a range of techniques including fourier transformed Infrared spectroscopy (FTIR), raman spectroscopy, Energy dispersive X-ray spectroscopy (EDX), dcanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and BET surface area measurement. The results show that synthesized SMSPs have mean diameter of 627±140 nm at room temperature and decreases to 408±156 nm at 60 °C. SMSPs also exhibited high BET surface area (627 m2/g) that determines its high efficiency for uptake of iron into the mesoporous structure. However, loss of spherical structure is also witnessed on increasing silica to iron ratio (1:3) during synthesis. Series of batch experiments were carried out to test dechlorination efficiency of the synthesized Fe-SMSPs against TCE. HPLC data indicated rapid decrease and removal of 25 ppm TCE in two hours at room temperature. Mass spectrometry revealed formation of hydrocarbons as dechlorination products. The present research concludes that the synthesized Fe-SMSPs have a promising potential to be used for dechlorination of TCE contaminated water. This has special preference for underground water treatment. Future prospects determine applicability of these materials for dechlorination of other chlorinated organic compounds than TCE.