Reductive Transformation of Aqueous Pollutants Using Heterogeneous Photocatalysis: A Review

2022 ◽  
Author(s):  
Bhaumik R. Shah ◽  
Upendra D. Patel
Keyword(s):  
Heterogeneous Photocatalysis ◽  
Reductive Transformation

Polycaprolactone based membranes for the degradation of diclofenac present in water samples using ZnO nanoparticles as the active agent

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3153-3161
Author(s):  
Marco Antonio Juárez Sánchez ◽  
Miguel Ángel Meléndez Lira ◽  
Celestino Odín Rodríguez Nava
Keyword(s):  
Zno Nanoparticles ◽  
Wastewater Treatment Plants ◽  
Active Agent ◽  
Heterogeneous Photocatalysis ◽  
Nano Particles ◽  
Electrical Characteristics ◽  
Unit Operation ◽  
Fields Of Study ◽  
Drug Contamination ◽  
Positive Results

AbstractDrug contamination in water is one of the current fields of study. Since 1990, the presence of drugs in drinking water has been a concern to scientists and public. In Mexico, these organic compounds are not efficiently removed in wastewater treatment plants; therefore, alternative methodologies have been studied that allow these compounds to have a high percentage of degradation or be completely degraded. One example of these techniques is heterogeneous photocatalysis which has obtained positive results in the degradation of drugs using ZnO nanoparticles. These are commonly selected for their electrical characteristics, even though they disperse in water and an additional unit operation is required to separate them from the liquid medium. To eliminate drugs with nano particles in a single stage, polycaprolactone-based membranes with adhered ZnO nanoparticles, by means of electrospinning, were prepared to degrade drugs such as diclofenac. The technique used has shown to efficiently break down diclofenac in 4 hours according to the capillary electrophoresis readings.

Reductive transformation of tetrachloroethylene to ethylene and ethane by an anaerobic filter

1997 ◽  
Vol 36 (6-7) ◽  
pp. 125-132 ◽  
Author(s):  
Toshiya Komatsu ◽  
Jun Shinmyo ◽  
Kiyoshi Momonoi
Keyword(s):  
Electron Donor ◽  
Laboratory Scale ◽  
Groundwater Contaminants ◽  
Reductive Transformation ◽  
Filter System ◽  
Anaerobic Filter ◽  
Anaerobic Microorganisms ◽  
Chlorinated Ethylenes ◽  
Start Up ◽  
Low Concentrations

Tetrachloroethylene (PCE) is one of the most common groundwater contaminants in Japan. PCE can be completely dechlorinated to ethylene (ETY) and ethane (ETA) by anaerobic microorganisms in the presence of a suitable electron donor. This study was conducted to examine the feasibility of using an anaerobic filter for the degradation of PCE in a bioremediation process. Laboratory-scale anaerobic filters were operated at 25°C using ethanol as the electron donor. Rapid start-up of the reactors was achieved by using anaerobic completely PCE-dechlorinating enrichment cultures as the inoculum. During the continuous operating periods, low concentrations (2.8 mg/L) of PCE were almost completely dechlorinated to ETY and ETA at hydraulic retention times of 49-15 hours with 100 mgCOD/L of ethanol. PCE concentrations as high as 80 mg/L was dechlorinated to ETY with a relatively low supply (200 mgCOD/L) of ethanol. Results of this study suggest that the anaerobic filter system is a feasible bioremediation process for the cleanup of groundwater which is contaminated by chlorinated ethylenes.

Treatment of ethylmercury chloride by heterogeneous photocatalysis with TiO2

2021 ◽  
Vol 411 ◽  
pp. 113205
Author(s):  
Emmanuel M. de la Fournière ◽  
Jorge M. Meichtry ◽  
Eduardo A. Gautier ◽  
Ana G. Leyva ◽  
Marta I. Litter
Keyword(s):  
Heterogeneous Photocatalysis

Toluene degradation by heterogeneous photocatalysis assisted with ozone in a tubular reactor: analysis over the reactor length

2021 ◽  
Author(s):  
Bárbara Maria Borges Ribeiro ◽  
Renato Carajelescov Nonato ◽  
Tânia Miyoko Fujimoto ◽  
Bianca Gvozdenovic Medina Bricio ◽  
Ursula Luana Rochetto Doubek ◽  
...  
Keyword(s):  
Tubular Reactor ◽  
Heterogeneous Photocatalysis ◽  
Toluene Degradation ◽  
Reactor Length

scholarly journals Heterogeneous Photocatalysis

2021 ◽  
Vol 5 (2) ◽  
pp. 26
Author(s):  
Mario J. Muñoz-Batista ◽  
Rafael Luque
Keyword(s):  
Heterogeneous Photocatalysis ◽  
Chemical Processes

Heterogeneous photocatalysis is a subtype of catalysis that refers to chemical processes catalysed by a semiconductor solid under proper illumination conditions [...]

scholarly journals A Review of Photoelectrocatalytic Reactors for Water and Wastewater Treatment

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1198
Author(s):  
Stuart McMichael ◽  
Pilar Fernández-Ibáñez ◽  
John Anthony Byrne
Keyword(s):  
Chemical Compounds ◽  
Research Area ◽  
Heterogeneous Photocatalysis ◽  
Semiconducting Materials ◽  
Electron Hole ◽  
Water And Wastewater Treatment ◽  
Aqueous Environments ◽  
Different Types ◽  
Water And Wastewater ◽  
Electrical Bias

The photoexcitation of suitable semiconducting materials in aqueous environments can lead to the production of reactive oxygen species (ROS). ROS can inactivate microorganisms and degrade a range of chemical compounds. In the case of heterogeneous photocatalysis, semiconducting materials may suffer from fast recombination of electron–hole pairs and require post-treatment to separate the photocatalyst when a suspension system is used. To reduce recombination and improve the rate of degradation, an externally applied electrical bias can be used where the semiconducting material is immobilised onto an electrically conducive support and connected to a counter electrode. These electrochemically assisted photocatalytic systems have been termed “photoelectrocatalytic” (PEC). This review will explain the fundamental mechanism of PECs, photoelectrodes, the different types of PEC reactors reported in the literature, the (photo)electrodes used, the contaminants degraded, the key findings and prospects in the research area.

scholarly journals Turning Carbon Dioxide and Ethane into Ethanol by Solar-Driven Heterogeneous Photocatalysis over RuO2- and NiO-co-Doped SrTiO3

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 461
Author(s):  
Larissa O. Paulista ◽  
Josep Albero ◽  
Ramiro J. E. Martins ◽  
Rui A. R. Boaventura ◽  
Vítor J. P. Vilar ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Maximum Yield ◽  
Ruthenium Oxide ◽  
Photogenerated Electron ◽  
Band Gap Energy ◽  
Heterogeneous Photocatalysis ◽  
Solar Irradiation ◽  
Batch Mode ◽  
Molar Ratios ◽  
Co Doped

The current work focused on the sunlight-driven thermo-photocatalytic reduction of carbon dioxide (CO2), the primary greenhouse gas, by ethane (C2H6), the second most abundant element in shale gas, aiming at the generation of ethanol (EtOH), a renewable fuel. To promote this process, a hybrid catalyst was prepared and properly characterized, comprising of strontium titanate (SrTiO3) co-doped with ruthenium oxide (RuO2) and nickel oxide (NiO). The photocatalytic activity towards EtOH production was assessed in batch-mode and at gas-phase, under the influence of different conditions: (i) dopant loading; (ii) temperature; (iii) optical radiation wavelength; (vi) consecutive uses; and (v) electron scavenger addition. From the results here obtained, it was found that: (i) the functionalization of the SrTiO3 with RuO2 and NiO allows the visible light harvest and narrows the band gap energy (ca. 14–20%); (ii) the selectivity towards EtOH depends on the presence of Ni and irradiation; (iii) the catalyst photoresponse is mainly due to the visible photons; (iv) the photocatalyst loses > 50% efficiency right after the 2nd use; (v) the reaction mechanism is based on the photogenerated electron-hole pair charge separation; and (vi) a maximum yield of 64 μmol EtOH gcat−1 was obtained after 45-min (85 μmol EtOH gcat−1 h−1) of simulated solar irradiation (1000 W m−2) at 200 °C, using 0.4 g L−1 of SrTiO3:RuO2:NiO (0.8 wt.% Ru) with [CO2]:[C2H6] and [Ru]:[Ni] molar ratios of 1:3 and 1:1, respectively. Notwithstanding, despite its exploratory nature, this study offers an alternative route to solar fuels’ synthesis from the underutilized C2H6 and CO2.

scholarly journals Control of Selectivity in Heterogeneous Photocatalysis by Tuning TiO2 Morphology for Water Treatment Applications

10.5772/62296 ◽  
2016 ◽  
Vol 6 ◽  
pp. 12 ◽  
Author(s):  
Ahmed A. Farghali ◽  
Ayman H. Zaki ◽  
Mohamed H. Khedr
Keyword(s):  
Water Treatment ◽  
Heterogeneous Photocatalysis

scholarly journals Factors influencing the adsorption and photocatalysis of direct red 80 in the presence of a TiO2: Equilibrium and kinetics modeling

2021 ◽  
pp. 174751982198996
Author(s):  
Moussa Abbas
Keyword(s):  
Elimination Rate ◽  
Threshold Value ◽  
Heterogeneous Photocatalysis ◽  
Order Kinetic ◽  
Batch Mode ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Equilibrium And Kinetics ◽  
Order Kinetic Model ◽  
Charge Point

Among the different photocatalysts, TiO2 ( Eg = 3.1 eV, zero charge point (pHpzc = 6.3), and surface = 55 m2/g) is currently the most efficient and the most studied semiconductor due to its strong photocatalytic activity, non-toxicity, and chemical stability. The elimination of DR-80 on TiO2 is studied by adsorption in batch mode and by application of heterogeneous photocatalysis onto TiO2 under UV irradiation. The effects of contact time (0–60 min), initial pH (3–11), dose of the adsorbent (0.5–3 g L−1), and DR-80 concentration (40–60 mg L−1) on the adsorption of DR-80 by TiO2 are studied for optimization of these parameters. The kinetic parameters, rate constants, and equilibrium adsorption capacities are calculated and discussed for each applied theoretical model. The adsorption of DR-80 is well described by the pseudo-first-order kinetic model. The fitting of the adsorption isotherms shows that the models of Langmuir and Temkin offering a better fit and an adsorption 64.102 mg/g at 25 °C of DR-80 are eliminated. The results showed that the photocatalytic efficiency strongly depends on the pH while the initial rate of photodegradation is proportional to the catalyst dose, and becomes almost constant above a threshold value. It was found that the photodegradation is favored at low DR-80 concentrations in accordance with the Langmuir–Hinshelwood model with the constants Kad = 6.5274 L/mg and KL–H = 0.17818 mg L−1 min. However, the adsorption is improved for high DR-80 concentrations. It is found that the degradation depends on both the temperature and the pH with a high elimination rate at high temperature. The photocatalyst TiO2 has a better activity for the degradation of DR-80, compared to some commercial catalysts that have been described in the literature.

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