Mechanism for catalytic ozonation of p-nitrophenol in water with titanate nanotube supported manganese oxide

RSC Advances ◽  
2015 ◽  
Vol 5 (123) ◽  
pp. 101975-101981 ◽  
Author(s):  
Shengtao Xing ◽  
Xiaoyang Lu ◽  
Xinjian Zhang ◽  
Yiyao Zhang ◽  
Zichuan Ma ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Organic Pollutants ◽  
Hydroxyl Radicals ◽  
Acid Sites ◽  
Catalytic Ozonation ◽  
Titanate Nanotube

A support with acid sites favored the adsorption of ozone, while the supported MnOx accelerated the decomposition of ozone into hydroxyl radicals for the mineralization of organic pollutants.

Preparation of Manganese Oxide Supported on Activated Carbon and its Application in Catalytic Ozonation of 4-Chlorophenol

2012 ◽  
Vol 538-541 ◽  
pp. 2285-2288 ◽  
Author(s):  
Bing Liu ◽  
Ai Min Li ◽  
Ming Fang Xia ◽  
Zhao Lian Zhu
Keyword(s):  
Waste Water ◽  
Activated Carbon ◽  
Manganese Oxide ◽  
Organic Pollutants ◽  
Granular Activated Carbon ◽  
Catalytic Ozonation ◽  
Synergic Effect ◽  
Highly Dispersed ◽  
Refractory Organic Pollutants

Catalyst with manganese oxide highly dispersed on granular activated carbon (MnOx/GAC) was fabricated by impregnating GAC in MnCl2 solution and characterized by several techniques. The performance of manganese catalyst was investigated in catalytic ozonation of 4-chlorophenol in water. Manganese catalyst exhibits better efficiency than the original granular activated carbon, due to the synergic effect between activated carbon and manganese oxide. MnOx/GAC, produced by a simple methodin situ, is promising in catalytic ozonation of refractory organic pollutants in waste water.

Catalytic ozonation of fenofibric acid over alumina-supported manganese oxide

2010 ◽  
Vol 183 (1-3) ◽  
pp. 271-278 ◽  
Author(s):  
Roberto Rosal ◽  
María S. Gonzalo ◽  
Antonio Rodríguez ◽  
Eloy García-Calvo
Keyword(s):  
Manganese Oxide ◽  
Catalytic Ozonation ◽  
Fenofibric Acid

Oxidation of Organic Pollutants of Water to Mineralization by Catalytic Ozonation

2005 ◽  
Vol 27 (2) ◽  
pp. 115-128 ◽  
Author(s):  
V. Fontanier ◽  
V. Farines ◽  
J. Albet ◽  
S. Baig ◽  
J. Molinier
Keyword(s):  
Organic Pollutants ◽  
Catalytic Ozonation

scholarly journals Comparative study on heterogeneous and homogeneous catalytic ozonation efficiency in micropollutants' removal

2021 ◽  
Author(s):  
S. Psaltou ◽  
E. Kaprara ◽  
M. Mitrakas ◽  
A. Zouboulis
Keyword(s):  
Catalytic Activity ◽  
Organic Compounds ◽  
Hydroxyl Radicals ◽  
Ozone Concentration ◽  
Oxidation Reaction ◽  
Physicochemical Characteristics ◽  
Catalytic Ozonation ◽  
Experimental Conditions ◽  
Kinetic Rate ◽  
Kinetic Rate Constants

Abstract Catalytic ozonation was applied for the removal of small concentrations (4 μM) of micropollutants benzotriazole, carbamazepine, p-CBA from aqueous solutions at pH 7. These compounds present different physicochemical characteristics and different kinetic rate constants, when reacting with ozone or hydroxyl radicals in range of <0.15–3 × 105, 5.2 × 109, and 8.8 × 109 M−1s−1, respectively. Calcite was used as heterogeneous catalyst and its catalytic activity evaluated, by applying (and optimized) different experimental conditions (i.e., pH, temperature, ozone concentration), concerning the removal efficiency of p-CBA. Study of micropollutants' removal showed all examined organic compounds can be sufficiently removed by application of catalytic ozonation either by use of calcite, or by presence of Co(II) or Fe(II) (applied as homogeneous catalysts), while the optimum catalyst between them was found to be calcite. Carbamazepine with kO3 = 3 × 105 M−1s−1 can be easily removed, even by application of single ozonation, while benzotriazole and p-CBA resulted in 50% and 68.2% higher removal after application of catalytic ozonation within 3 min of oxidation reaction, due to acceleration of hydroxyl radicals' production by presence of calcite in the ozonation system. The contribution of hydroxyl radicals in removal of all three micropollutants was evaluated by extraction of Rct and f•OH parameters.

scholarly journals Photochemical Degradation of Short-Chain Chlorinated Paraffins in Aqueous Solution by Hydrated Electrons and Hydroxyl Radicals

2022 ◽  
Author(s):  
Brian DiMento ◽  
Cristina Tusei ◽  
Christoph Aeppli
Keyword(s):  
Organic Pollutants ◽  
Hydroxyl Radicals ◽  
Surface Waters ◽  
Rate Constants ◽  
Degradation Rate ◽  
Chlorine Content ◽  
Photochemical Degradation ◽  
Model Compounds ◽  
Chlorinated Paraffins ◽  
Hydrated Electrons

Short-chain chlorinated paraffins (SCCPs) are a complex mixture of polychlorinated alkanes (C10-C13, chlorine content 40-70%), and have been categorized as persistent organic pollutants. However, there are knowledge gaps about their environmental degradation, particularly the effectiveness and mechanism of photochemical degradation in surface waters. Photochemically-produced hydrated electrons (e-(aq)) have been shown to degrade highly chlorinated compounds in environmentally-relevant conditions more effectively than hydroxyl radicals (·OH), which can degrade a wide range of organic pollutants. This study aimed to evaluate the potential for e-(aq) and ·OH to degrade SCCPs. To this end, the degradation of SCCP model compounds was investigated under laboratory conditions that photochemically produced e-(aq) or ·OH. Resulting SCCP degradation rate constants for e-(aq) were on the same order of magnitude as well-known chlorinated pesticides. Experiments in the presence of ·OH yielded similar or higher second-order rate constants. Trends in e-(aq) and ·OH SCCP model compounds degradation rate constants of the investigated SCCPs were consistent with that of other chlorinated compounds, with higher chlorine content producing in higher rate constants for e-(aq) and lower for ·OH. Above a chlorine:carbon ratio of approximately 0.6, the e-(aq) second-order rate constants were higher than rate constants for ·OH reactions. Results of this study furthermore suggest that SCCPs are likely susceptible to photochemical degradation in sunlit surface waters, facilitated by dissolved organic matter that can produce e-(aq) and ·OH when irradiated.

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