Controlled polyethylene glycol and activated carbon interaction with nanoscale zerovalent iron for trichloroethylene degradation

Abstract

Nanoscale zerovalent iron (Fe0) on carbon materials was successfully synthesized via a simple one-step pyrolysis of coir pith with iron precursor. The Fe0 dispersion over activated carbon (AC) and stability was amended by adding polyethylene glycol (PEG)/carboxymethyl cellulose (CMC). The transmission electron microscopy results reveal the homogeneous distribution of Fe0 (~20 nm) on the surface of AC. In addition, the crystal patterns and valence states of Fe0 nanoparticles were evaluated by X-ray diffraction, and X-ray photoelectron spectroscopy, respectively. Trichloroethylene (TCE), one common pollutant in the groundwater, was used to understand the catalytic ability of Fe/AC. The pseudo-first-order kinetic model was applied for TCE removal rate. Fe/AC shows 80% TCE removal in 24 h reaction time, due to its porous structure and large surface area. PEG-Fe/AC composite demonstrated 90.4% TCE dechlorination efficiency in 45 min (kobs 0.29 min−1). The enhanced dechlorination was recorded due to perfect PEG and Fe0 ratio, in which PEG restricted the arial oxidation of Fe0. The as-synthesized nanocomposite was further evaluated for its high stability and efficacy by consecutive eight successive TCE removal cycles. This study demonstrates that one-pot synthesized PEG-Fe/AC composite can effectively remove chlorinated compounds in water, which can be beneficial to the future research applications.