Degradation of 2,4-dichlorophenol using combined approach based on ultrasound, ozone and catalyst

Abstract

The present work investigates the application of ultrasound and ozone operated individually and in combination with catalyst (ZnO and CuO) for establishing the possible synergistic effects for the degradation of 2,4-dichlorophenol. The dependency of extent of degradation on the operating parameters like temperature (over the range of 30-36°C), initial pH (3-9), catalyst as ZnO (loading of 0.025-0.15g/L) and CuO (loading of 0.02-0.1g/L) and initial concentration of 2,4-DCP (20-50ppm) has been established to maximize the efficacy of ultrasound (US) induced degradation. Using only US, the maximum degradation of 2,4-DCP obtained was 28.85% under optimized conditions of initial concentration as 20ppm, pH of 5 and temperature of 34°C. Study of effect of ozone flow rate for approach of only ozone revealed that maximum degradation was obtained at 400mg/h ozone flow rate. The combined approaches such as US+O, US+ZnO, US+CuO, O+ZnO, O+CuO, US+O+ZnO and US+O+CuO have been subsequently investigated under optimized conditions and observed to be more efficient as compared to individual approaches. The maximum extent of degradation for the combined operation of US+O (400mg/h)+ZnO (0.1g/L) and US+O (400mg/h)+CuO (0.08g/L) has been obtained as 95.66% and 97.03% respectively. The degradation products of 2,4-DCP have been identified using GC-MS analysis and the toxicity analysis has also been performed based on the anti-microbial activity test (agar-well diffusion method) for the different treatment strategies. The present work has conclusively established that the combined approach of US+O+CuO was the most efficient treatment scheme resulting in near complete degradation of 2,4-DCP with production of less toxic intermediates.

Hybrid Treatment Strategies Based on Hydrodynamic Cavitation, Advanced Oxidation Processes, and Aerobic Oxidation for Efficient Removal of Naproxen

“…The maximum extent of degradation of 28.9% was obtained at 10 ppm, with the rate constant being 3.1 × 10 –3 min –1 , whereas only 13.7% degradation with rate constant being 1.2 × 10 –3 min –1 was obtained for an initial NAP concentration of 50 ppm (Figure b). The observed results are attributed to the fact that an increase in the initial concentration increases the number of pollutant molecules, whereas the total generated OH radicals remains the same, which ultimately reduces the extent of degradation . A similar trend of decrease in the extent of degradation with an increase in initial concentration was reported by Jawale at al .…”

“…The observed results are attributed to the fact that an increase in the initial concentration increases the number of pollutant molecules, whereas the total generated OH radicals remains the same, which ultimately reduces the extent of degradation. 32 A similar trend of decrease in the extent of degradation with an increase in initial concentration was reported by Jawale at al. 33 for the case of potassium ferrocyanide over the range of initial concentration as 20−200 ppm.…”

Effect of the Precursor on the Synthesis of ZnO and Its Photocatalytic Activity

“…Macías-Sánchez et al [86] used an aqueous solution of a mixture of 20 mg L −1 2,4-D and 5 mg L −1 picloram adjusted to pH 7 under visible light radiation ≥ 400 nm and found a mineralization efficiency of 0.2%. Barik and Gogate [87] investigated sonocatalytic degradation of 2,4-DCP using the process of ultrasonic irradiation in combination with ZnO nanoparticles and reported achieving, under conditions of initial concentration of 20 mg L −1 of pollutant and with a dose of 0.1 g L −1 of ZnO, a TOC removal of 24.6%.…”

Bioinspired Synthesis of Carbon Dots/g-C3N4 Nanocomposites for Photocatalytic Application

“…Endocrine disrupting chemicals (EDCs) are chemical compound which might disrupt the endocrine system, eventually causing harmful effects in an intact organism [1]. Among all EDCs, 2,4-dichlorophenol (2,4-DCP) is regarded as one of the main pollutants in varied industrial effluents owing to its wide usage in pesticides, herbicides, insecticide, and antiseptic manufacturing process [2]. 2,4-DCP is very recalcitrant and difficult to remove especially in contaminated groundwater.…”