Catalytic activity and mechanism of ordered mesoporous iron oxides on hydrogen peroxide for degradation of norfloxacin in water at neutral pH

2017 ◽  
Vol 14 (6) ◽  
pp. 361 ◽  
Author(s):  
Zhen Yuan ◽  
Minghao Sui ◽  
Jianrui Yang ◽  
Pan Li ◽  
Zhiran Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Specific Surface Area ◽  
High Catalytic Activity ◽  
Water And Wastewater Treatment ◽  
H2o2 Decomposition ◽  
Neutral Ph ◽  
Treatment Techniques ◽  
Ordered Mesoporous ◽  
H2o2 Oxidation ◽  
Decomposition Of H2o2

Environmental contextNorfloxacin is widely used as a human and veterinary medicine for its broad-spectrum antibacterial activity. It is chemically stable, rendering it difficult to remove from water using the traditional water and wastewater treatment techniques. We investigate the use of iron oxide catalysts for the degradation of norfloxacin in water prior to its release into the environment. AbstractThe catalytic activity of ordered mesoporous Fe2O3 (om-Fe2O3) on H2O2 oxidation of norfloxacin (NOR) under neutral pH conditions in water was investigated. Using non-ordered-mesoporous Fe2O3 as a reference (nom-Fe2O3), om-Fe2O3 with high specific surface area of 176.4m2g−1 and a uniform pore structure exhibited high catalytic activity in the decomposition of H2O2 as well as the degradation of NOR at neutral pH. Compared with nom-Fe2O3, om-Fe2O3 promoted the decomposition of H2O2 differently. The adsorption capacity of om-Fe2O3 for NOR was much higher than that of nom-Fe2O3. The adsorption efficiency of NOR on om-Fe2O3 accounted for 60.2–64.9% of the degradation efficiency in om-Fe2O3/H2O2. tert-Butanol (TBA), which is resistant to adsorption by om-Fe2O3, had no effect on the degradation of NOR by om-Fe2O3/H2O2. However, the presence of tromethamine (TMA), which was favourable to adsorption by om-Fe2O3, inhibited the degradation of NOR significantly. Based on the different effects of TBA and TMA on the degradation of NOR, it is proposed that the catalytic degradation of NOR may occur on the surface of om-Fe2O3. Hydroxyl radicals (·OH) generated may be bound on the surface of om-Fe2O3 without diffusing into aqueous solution. It is proposed that the adsorption of target organic pollutants must be considered when assessing the suitability of the om-Fe2O3/H2O2 process. The mechanism of om-Fe2O3 in promoting H2O2 decomposition into OH was also investigated.

The Influence of Fe/Al Molar Ratio on Microreactor-Based Catalyst Preparation and Carbon Nanotube Preparation

2021 ◽  
Vol 1036 ◽  
pp. 130-136
Author(s):  
Ting Qun Tan ◽  
Lei Geng ◽  
Yan Lin ◽  
Yan He
Keyword(s):  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Small Diameter ◽  
High Specific Surface Area ◽  
Detection Methods ◽  
Molar Ratio ◽  
High Catalytic Activity

In order to prepare carbon nanotubes with high specific surface area, small diameter, low resistivity, high purity and high catalytic activity, the Fe-Mo/Al2O3 catalyst was prepared based on the microreactor. The influence of different Fe/Al molar ratios on the catalyst and the carbon nanotubes prepared was studied through BET, SEM, TEM and other detection methods. Studies have shown that the pore structure of the catalyst is dominated by slit pores at a lower Fe/Al molar ratio. The catalytic activity is the highest when the Fe/Al molar ratio is 1:1, reaching 74.1%. When the Fe/Al molar ratio is 1:2, the catalyst has a higher specific surface area, the maximum pore size is 8.63 nm, and the four-probe resistivity and ash content of the corresponding carbon nanotubes are the lowest. The higher the proportion of aluminum, the higher the specific surface area of the catalyst and the carbon nanotubes, and the finer the diameter of the carbon nanotubes, which gradually tends to relax. The results show that when the Fe/Al molar ratio is 1:2, although the catalytic activity of the catalyst is not the highest, the carbon nanotubes prepared have the best performance.

Pyrite cinder as a cost-effective heterogeneous catalyst in heterogeneous Fenton reaction: decomposition of H2O2 and degradation of Acid Red B

2014 ◽  
Vol 70 (9) ◽  
pp. 1548-1554 ◽  
Author(s):  
Deli Wu ◽  
Yanxia Liu ◽  
Dong Duan ◽  
Luming Ma
Keyword(s):  
Catalytic Activity ◽  
Metal Ions ◽  
Cost Effective ◽  
High Catalytic Activity ◽  
Order Kinetic ◽  
Pyrite Cinder ◽  
Heterogeneous Fenton ◽  
Kinetic Rate Constant ◽  
Heterogeneous Fenton Reaction ◽  
Decomposition Of H2o2

Pyrite cinder (PyC) was employed as a heterogeneous Fenton-like catalyst, and its catalytic activity was evaluated in view of the effects of catalyst dosage, pH and leaching metal ions. PyC showed significant reactivity, and the pseudo-first-order kinetic rate constant for decomposition of H2O2 and degradation of Acid Red B (ARB) were 3.4 and 14.89 (10−3 min−1) respectively when pH = 5. When 20 g/L PyC was added into 10 mM H2O2 solution in neutral pH, H2O2 could be completely degraded within 4 h, and more than 90% ARB was removed. Leaching metal ions from PyC were found to have little effect on decomposition of H2O2 or on degradation of ARB. PyC still had high catalytic activity after five successive runs. The decomposition mechanism of H2O2 was analyzed and the Haber–Weiss mechanism was employed in this paper. The electron spin resonance image showed •OH was produced and increased between 3 and 5 min in the PyC catalyzing H2O2 reaction, which demonstrated that PyC had a durable ability to produce •OH.

scholarly journals Biodiesel Production over Niobium-Containing Catalysts: A Review

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5506
Author(s):  
Daniel Carreira Batalha ◽  
Márcio José da Silva
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Raw Materials ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Main Reaction ◽  
High Catalytic Activity

Nowadays, the synthesis of biofuels from renewable raw materials is very popular. Among the various challenges involved in improving these processes, environmentally benign catalysts compatible with an inexpensive feedstock have become more important. Herein, we report the recent advances achieved in the development of Niobium-containing heterogeneous catalysts as well as their use in routes to produce biodiesel. The efficiency of different Niobium catalysts in esterification and transesterification reactions of lipids and oleaginous raw materials was evaluated, considering the effect of main reaction parameters such as temperature, time, catalyst load, and oil:alcohol molar ratio on the biodiesel yield. The catalytic performance of Niobium compounds was discussed considering the characterization data obtained by different techniques, including NH3-TPD, BET, and Pyr-FT-IR analysis. The high catalytic activity is attributed to its inherent properties, such as the active sites distribution over a high specific surface area, strength of acidity, nature, amount of acidic sites, and inherent mesoporosity. On top of this, recycling experiments have proven that most Niobium catalysts are stable and can be repeatedly used with consistent catalytic activity.

scholarly journals Heterogeneous Fenton-like degradation of EDTA in an aqueous solution with enhanced COD removal under neutral pH

2020 ◽  
Author(s):  
Junfeng Hua ◽  
Mei Huang
Keyword(s):  
Catalytic Activity ◽  
Ethylenediaminetetraacetic Acid ◽  
Oxygen Demand ◽  
Morphological Characterization ◽  
Cod Removal ◽  
High Catalytic Activity ◽  
Heterogeneous Fenton ◽  
Neutral Ph ◽  
Effects Of Ph ◽  
Fe3o4 Mnps

Abstract By providing the key carbon and nitrogen elements needed for eutrophication, the potential toxicity of ethylenediaminetetraacetic acid (EDTA) prompts the exploration of effective treatment methods to minimize the amount of EDTA released into the environment. In this study, Fe3O4 magnetic nanoparticles (MNPs) were prepared and used as catalysts to study the mineralization of EDTA in Fenton-like reactions under neutral pH. Fe3O4 MNPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET). The effects of pH, ferric ion leaching, and H2O2 concentration on chemical oxygen demand (COD) removal of EDTA were investigated. The morphological characterization of the nanoparticles suggests a quasi-spherical structure with small particle size and a surface area of 49.9 m2/g. The results show that Fe3O4 MNPs had good catalytic activity for the mineralization of EDTA under pH 5.0–9.0. The optimum conditions for the COD removal of 45% at pH 7.0 were: 40 mM H2O2, 10 mM Fe3O4, and 1 g/L EDTANa2·2H2O at 303 K. Fe3O4 MNPs maintained high catalytic activity after five cycles of continuous degradation of EDTA. According to reactive oxidizing species measurements obtained by electron spin resonance (ESR), it was confirmed that HO· free radicals, presented in the H2O2/Fe3O4 MNPs heterogeneous Fenton-like reaction, were the primary active group in the removal of EDTA. These features can be considered beneficial to the application of Fe3O4 MNPs towards industrial wastewater treatment.

Effects of preparation method and Sm2O3 promoter on CO methanation by a mesoporous NiO–Sm2O3/Al2O3 catalyst

2018 ◽  
Vol 42 (15) ◽  
pp. 13096-13106 ◽  
Author(s):  
Qing Liu ◽  
Hongyuan Yang ◽  
Hao Dong ◽  
Wei Zhang ◽  
Bing Bian ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Preparation Method ◽  
High Catalytic Activity ◽  
Co Methanation ◽  
Methanation Reaction ◽  
Ordered Mesoporous ◽  
Al2o3 Catalyst

Well-dispersed Ni and Sm2O3 nanoparticles embedded in an ordered mesoporous Al2O3 material simultaneously exhibit high catalytic activity and stability for the CO methanation reaction.

Surface Functionalization of Ordered Mesoporous Hollow Carbon Spheres with Ru Organometallic Compounds as Supports of Low-Pt Content Nanocatalysts for Alkaline Hydrogen and Oxygen Evolution Reactions

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2973-2989
Author(s):  
J.C. Martínez-Loyola ◽  
I.L. Alonso-Lemus ◽  
M.E. Sánchez-Castro ◽  
B. Escobar-Morales ◽  
J.R. Torres-Lubián ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Performance ◽  
Pt Nanoparticles ◽  
Organometallic Compounds ◽  
High Catalytic Activity ◽  
Carbon Spheres ◽  
Ordered Mesoporous ◽  
Electrochemical Water Splitting ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

AbstractHerein, we report a methodology that leads to the formation of Ru metallic sites, followed by the development and anchorage of Pt-Ru alloyed nanoparticles on the surface of Ordered Mesoporous Hollow Carbon Spheres (OMHCS). Along with the Ru sites, it is demonstrated that the functionalization promotes the formation of functional groups on the surface of the OMHCS. In a first stage, OMHCS are functionalized with the [(η6-C6H5OCH2CH2OH)RuCl2]2 (Ru-dim) and [(η6-C6H4CH(CH3)2CH3)RuCl2]2 (Ru-cym) organometallic compounds. Afterwards, Pt nanoparticles are dispersed by the microwave-assisted polyol method over the functionalized supports obtaining the low-metal content 5 wt. % Pt/OMHCSRu-dim and Pt/OMHCSRu-cym nanocatalysts. The degree of Ru alloyed is found to be around 35%. The low-Pt content Pt/OMHCSRu-cym and Pt/OMHCSRu-dim exhibit a higher catalytic activity for the Oxygen (OER) and the Hydrogen (HER) Evolution Reactions than the Pt/C benchmark and the Pt/OMHCS nanocatalysts. The overpotential for the OER at 10 mA cm-2 (ηOER) is 300 mV and 210 mV smaller at Pt/OMHCSRu-cym and Pt/OMHCSRu-dim compared to Pt/C, respectively. The corresponding values of the HER at -10 mA cm-2 (ηHER) are 14 and 18 mV smaller, respectively. The high catalytic activity of Pt/OMHCSRu-cym and Pt/OMHCSRu-dim has been attributed in part to the presence of Ru0 and RuO2 species from organometallic functionalization, and the modification of the d-valence band of Pt. Their high performance for the OER and the HER opens new lines of research for the design of nanocatalysts for alkaline electrochemical water splitting.

Highly Ordered Mesoporous WO3 with Excellent Catalytic Performance and Reusability for Deep Oxidative Desulfurization

NANO ◽  
2015 ◽  
Vol 10 (05) ◽  
pp. 1550075 ◽  
Author(s):  
Zhenghua Li ◽  
Heon Jong Jeong ◽  
Kumarsrinivasan Sivaranjani ◽  
Byung Jin Song ◽  
Su Bin Park ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Oxidative Desulfurization ◽  
High Catalytic Activity ◽  
Ordered Mesoporous ◽  
Model Oil ◽  
Sulfur Containing ◽  
Sulfur Containing Compounds

Highly ordered mesoporous tungsten trioxide ( WO 3) with high surface area (75 m2/g) and well-defined mesopores were successfully prepared through a hard templating method using a mesoporous silica KIT-6 as a template and ( NH 4)6 H 2 W 12 O 40 ⋅ x H 2 O as a tungsten precursor. Oxidative desulfurization of a model oil with H 2 O 2 as the oxidant was carried out at 50°C under atmospheric pressure in order to analyze the catalytic activity. The desulfurization reactions were optimized by various kinds of reaction parameters such as H 2 O 2/ S molar ratio, reaction temperatures and series of sulfur-containing compounds [dibenzothiophene (DBT), benzothiophene (BT) and 4,6-dimethyl dibenzothiophene (4,6-DMBT)]. Excellent catalytic activity for the removal of the sulfur-containing compounds from the model oil was observed with mesoporous WO 3 catalyst, where the activity was maintained during 5 recycle tests without any regeneration process. The high catalytic activity and durability is mainly attributed to well-defined mesopores and high surface area of mesoporous WO 3 catalyst.

Methanation of carbon monoxide on ordered mesoporous NiO–TiO2–Al2O3 composite oxides

RSC Advances ◽  
2016 ◽  
Vol 6 (25) ◽  
pp. 20971-20978 ◽  
Author(s):  
Qing Liu ◽  
Yuanyu Tian ◽  
Hongmei Ai
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Confinement Effect ◽  
High Catalytic Activity ◽  
Composite Oxides ◽  
Al2o3 Composite ◽  
Ordered Mesoporous

An ordered mesoporous NiO–TiO2–Al2O3 catalyst can simultaneously exhibit high catalytic activity and stability, due to the confinement effect of the mesopore channels and the incorporation of the TiO2 species.

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