Degradation of trace aqueous 4-chloro-2-nitrophenol occurring in pharmaceutical industrial wastewater by ozone

Abstract

ABSTRACT:Degradation of 4-chloro-2-nitro phenol by ozonation in aqueous solution was studied in a semi batch reactor under constant ozone dosage and variable pH conditions. The effectiveness of the process was estimated based on the degree of conversion of 4-chloro-2-nitro phenol. It was observed that ozonation is more effective at alkaline reaction of medium than other conditions. The degree of conversion achieved (at the first 5 minutes of the process)at pH 9 was 99.64% compared to 99.03% and 77.35% at pH 7 and 3, respectively. Another parameter used to quantify the 4-chloro-2-nitrophenol during ozonation was the pseudo first order rate constant k [min -1 ]. Results showed that the rate constant of the process was approximately much higher at the alkaline pH compared to acidic ones. A considerable improvement in chemical oxygen demand removal was observed at pH above 7. At pH 9, the reduction in chemical oxygen demand at the end of the process reached 56.9 %. The degree of organically bounded nitrogen conversion to nitrate was higher at pH 3. Of the total organic carbon reduction, 15.89 % was observed at pH 9. The 4-chloro-2-nitro phenol degradation intermediate products were analyzed by mass-spectrometry. The main intermediate product was chlorophenol.

Treatment options for wastewater effluents from pharmaceutical companies

“…Chlorination and ozonation when compared for the removal of bisphenol A, 17β-estradiol, and 17α-ethinylestradiol and byproduct estrogenicity from distilled water showed comparable results with ozonation resulting in 75-99 % removal (Alum et al, 2004). Residual chlorine and ozone was found to be low with > 99 % loss of the parent compound (Gharbani et al, 2010). Lee and Von Gunten (2009) achieved 90 % conversion of estrogen, 17α-Ethinylestradiol with chlorine and increased the rate of 17β-Ethinylestradiol transformation by a factor of 3 with the addition of 0.25 mM Br -.…”

Neutral solar photo-Fenton degradation of 4-nitrophenol on iron-enriched hybrid montmorillonite-alginate beads (Fe-MABs)

“…Both photochemical (without beads) and photocatalytic experiments were carried out in two Pyrex glass reactors, each containing 25 mL of 2.8 mM (10 ppm) aqueous nitrophenol solution, resembling the typical concentration of this micropollutant class in pharmaceutical industries wastewater [33]. Initial pH was adjusted at 7.0 ± 0.1, and the solution was irradiated in batch mode in a solar simulator Suntest CPS (Atlas GmbH) at 290-600 nm under continuous stirring (300 rpm).…”

Photocatalytic, Sonolytic and Sonophotocatalytic Degradation of 4-Chloro-2-Nitro Phenol

“…Conventional wastewater treatment technologies have limitations to treat the wastewater containing these kinds of biorecalcitrant compounds, hence demanding advanced research to tackle complex wastewater treatment [7]. One of the promising technologies could be the use of single chemical oxidants, or the more effective destruction by the use of advanced oxidation processes (AOPs).…”