In Situ Removal of 2-Chlorophenol from Unsaturated Soils by Ozonation

Abstract

A mathematical model considering mass transfer process at the gas-liquid interface in soil ozonation was developed and validated with laboratory column experiments. Experimental data, specifically, concentration profiles of the organic contaminant and the ozone breakthrough curves, were obtained. In this model, the mass flux of ozone transferred from the gas phase into the liquid phase was described by the two-film theory incorporated with an enhancement factor approach as to account for chemical reactions. With the enhancement factor, the ozone gas transport in the experimental column can be described by an advection-dispersion-reaction equation with pseudo-second-order kinetics in the liquid film. This greatly simplifies the governing equations of the system. Results show that parameters such as degradation yield factor, diffusion coefficients, thickness of liquid film, ozone gas concentration, and gas-liquid interfacial area play an important role on the soil ozonation process. Using the scaled model, important universal dimensionless variables were obtained. The Stanton number (St) is the most important parameter in controlling the performance of system. When St approaches zero, the process is reaction-controlled. Conversely, when St is large, it is convection-controlled. Only when the system is convection-controlled (i.e., large St values) can an increase of ozone flow rate enhance the removal of soil contaminants such as 2-chlorophenol.

In situ ozonation of anthracene in unsaturated porous media

“…Recently, in situ chemical oxidation (ISCO) was proposed as an innovative treatment technology to remove PAHs and other organic pollutants in the subsurface [1]. In situ ozonation is such an ISCO that has been employed to clean up soils contaminated by PAHs [2,3], diesel fuel [4], 2-chlorophenol [5], aniline and trifluralin [6]. It was also employed as a pre-oxidation step for enhancing bioremediation of PAHs contaminated soils [7,8].…”

Monitoring of petroleum hydrocarbon degradative potential of indigenous microorganisms in ozonated soil

“…In ozonation, removal efficiency of chemicals depends on soil characteristics such as soil texture, moisture content, and SOM content Sung & Huang 2002). When different ozonation times were applied to the homogenized soil in this study, the initial amounts (kg soil À1 ) of TPH (2651.5 mg) and aromatics (278.6 mg) in the soil decreased with increased ozonation time ( Figure 2) and initial fast removal and subsequent slow removal patterns were observed.…”

“…Many studies have shown that ozonation is effective in removing contaminants such as petroleum hydrocarbons (PH) from soil (Hus & Masten 1997;Lim et al 2002;Nelson & Brown 1994;Stehr et al 2001;Sung & Huang 2002). Molecular ozone or its decomposition products (e.g., hydroxyl radicals) react with organic compounds to convert them into oxidized products.…”

Synthesis of akageneite (beta-FeOOH)/reduced graphene oxide nanocomposites for oxidative decomposition of 2-chlorophenol by Fenton-like reaction

“…The pH of initial suspension was adjusted to 4 or 9 by 0.1 M NaOH or HNO 3 . The reaction was initiated by 0.1 M H 2 O 2 , and the suspension was vibrated at a speed of 200 r min −1 .…”

“…Chlorophenols are aromatic compounds with chlorine, which are widely used in chemical industries, such as pesticides and dyes manufactures [1,2], as a consequence, leading to the exposure of chlorophenols in sediment of lakes and rivers [3], aerosols, and hazardous waste [4]. They are toxic and hardly biodegradable due to the stable C C bond in the chlorinated compounds [5].…”