scholarly journals Enhanced Photocatalytic Reduction of Cr(VI) by Combined Magnetic TiO2-Based NFs and Ammonium Oxalate Hole Scavengers

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 72 ◽  
Author(s):  
Yin-Hsuan Chang ◽  
Ming-Chung Wu
Keyword(s):  
Organic Contaminants ◽  
High Efficiency ◽  
Ammonium Oxalate ◽  
Reaction Rate Constant ◽  
Electron Hole ◽  
Tio2 Nanofibers ◽  
Tio2 Photocatalysts ◽  
Survival And Development ◽  
Hole Scavenger ◽  
Separation Behavior

Heavy metal pollution of wastewater with coexisting organic contaminants has become a serious threat to human survival and development. In particular, hexavalent chromium, which is released into industrial wastewater, is both toxic and carcinogenic. TiO2 photocatalysts have attracted much attention due to their potential photodegradation and photoreduction abilities. Though TiO2 demonstrates high photocatalytic performance, it is a difficult material to recycle after the photocatalytic reaction. Considering the secondary pollution caused by the photocatalysts, in this study we prepared Ag/Fe3O4/TiO2 nanofibers (NFs) that could be magnetically separated using hydrothermal synthesis, which was considered a benign and effective resolution. For the photocatalytic test, the removal of Cr(VI) was carried out by Ag/Fe3O4/TiO2 nanofibers combined with ammonium oxalate (AO). AO acted as a hole scavenger to enhance the electron-hole separation ability, thereby dramatically enhancing the photoreduction efficiency of Cr(VI). The reaction rate constant for Ag/Fe3O4/TiO2 NFs in the binary system reached 0.260 min−1, 6.95 times of that of Ag/Fe3O4/TiO2 NFs in a single system (0.038 min−1). The optimized Ag/Fe3O4/TiO2 NFs exhibited high efficiency and maintained their photoreduction efficiency at 90% with a recyclability of 87% after five cycles. Hence, taking into account the high magnetic separation behavior, Ag/Fe3O4/TiO2 NFs with a high recycling capability are a potential photocatalyst for wastewater treatment.

Pre-Industrial Experience in Solar Photocatalytic Mineralization of Real Wastewaters. Application to Pesticide Container Recycling

1999 ◽  
Vol 40 (4-5) ◽  
pp. 123-130 ◽  
Author(s):  
S. Malato ◽  
J. Blanco ◽  
C. Richter ◽  
B. Milow ◽  
M. I. Maldonado
Keyword(s):  
Organic Contaminants ◽  
Toxic Waste ◽  
Experimental Plant ◽  
Electron Hole ◽  
Particulate Suspensions ◽  
Photocatalytic System ◽  
Commercial Pesticide ◽  
Pesticide Container ◽  
By Products ◽  
Hole Recombination

Particulate suspensions of TiO2 irradiated with natural solar tight in a large experimental plant catalyse the oxidation of organic contaminants. The problem in using TiO2 as a photocatalyst is electron/hole recombination. One strategy for inhibiting e−/h+ recombination is to add other (irreversible) electron acceptors to the reaction. In many highly toxic waste waters where degradation of organic pollutants is the major concern, the addition of an inorganic anion to enhance the organic degradation rate may be justified. For better results, these additives should fulfil the following criteria: dissociate into harmless by-products and lead to the formation of ·OH or other oxidising agents. In this paper, we attempt to demonstrate the optimum conditions for the treatment of commercial pesticide rinsates found in the wastewater produced by a pesticide container recycling plant. The experiments were performed in one of the pilot plants of the largest solar photocatalytic system in Europe, the Detoxification Plants of the Plataforma Solar de Almería (PSA), in Spain. After testing ten different commercial pesticides, results show that peroxydisulphate enhances the photocatalytic miniralization of all of them. This study is part of an extensive project focused on the design of a solar photocatalytic plant for decontamination of agricultural rinsates in Almería (Spain).

scholarly journals Superior Degradation Performance of Nanoporous Copper Catalysts on Methyl Orange

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 913
Author(s):  
Jinyi Wang ◽  
Sen Yang
Keyword(s):  
Activation Energy ◽  
Methyl Orange ◽  
High Efficiency ◽  
Low Cost ◽  
Degradation Process ◽  
Copper Catalysts ◽  
Reaction Rate Constant ◽  
Nanoporous Structure ◽  
Intra Particle Diffusion ◽  
Different Temperatures

The development of low-cost and high-efficiency catalysts for wastewater treatment is of great significance. Herein, nanoporous Cu/Cu2O catalysts were synthesized from MnCu, MnCuNi, and MnCuAl with similar ligament size through one-step dealloying. Meanwhile, the comparisons of three catalysts in performing methyl orange degradation were investigated. One of the catalysts possessed a degradation efficiency as high as 7.67 mg·g−1·min−1. With good linear fitting by the pseudo-first-order model, the reaction rate constant was evaluated. In order to better understand the degradation process, the adsorption behavior was considered, and it was divided into three stages based on the intra-particle diffusion model. Three different temperatures were applied to explore the activation energy of the degradation. As a photocatalytic agent, the nanoporous structure of Cu/Cu2O possessed a large surface area and it also had low activation energy, which were beneficial to the excellent degradation performance.

scholarly journals Photocatalytic Liquid-Phase Selective Hydrogenation of 3-Nitrostyrene to 3-vinylaniline of Various Treated-TiO2 Without Use of Reducing Gas

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 329 ◽  
Author(s):  
Okorn Mekasuwandumrong ◽  
Saknarin Chaitaworn ◽  
Joongjai Panpranot ◽  
Piyasan Praserthdam
Keyword(s):  
Selective Hydrogenation ◽  
Consumption Rate ◽  
Rutile Phase ◽  
Optimum Amount ◽  
Electron Hole ◽  
Tio2 Photocatalysts ◽  
Reducing Gas ◽  
Pl Intensity ◽  
Different Gases ◽  
Hole Recombination

In this work, we investigate the effect of TiO2 properties on the photocatalytic selective hydrogenation of 3-nitrostyrene (3-NS) to 3-vinylaniline (3-VA). The P25-TiO2 photocatalysts were calcined at 600–900 °C using different gases (Air, N2, and H2) and characterized by XRD, N2 physisorption, XPS, UV-Vis, and PL spectroscopy. In the photocatalytic hydrogenation of 3-nitrostyrene in isopropanol, the selectivity of 3-vinylaniline of the treated TiO2 was almost 100%. A linear correlation between the 3-NS consumption rate and PL intensity was observed. Among the catalysts studied, P25-700-air, which possessed the lowest PL intensity, exhibited the highest photocatalytic activity due to the synergistic effect that resulted from its high crystallinity and the optimum amount of anatase/rutile phase content, leading to the reduction of the electron-hole recombination process.

scholarly journals Microcystis aeruginosa Synergistically Facilitate the Photocatalytic Degradation of Tetracycline Hydrochloride and Cr(VI) on PAN/TiO2/Ag Nanofiber Mats

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 628 ◽  
Author(s):  
Lei Wang ◽  
Changbo Zhang ◽  
Rong Cheng ◽  
Jafar Ali ◽  
Zhenbo Wang ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
High Efficiency ◽  
Reaction Rate Constant ◽  
Active Species ◽  
Harmful Algae ◽  
Cyanobacterial Blooms ◽  
Tetracycline Hydrochloride ◽  
Algae Blooms ◽  
Secondary Pollutants ◽  
Nanofiber Mats

Cyanobacterial blooms can cause serious damage to aquatic ecosystems. However, we have demonstrated that typical algae-blooming species Microcystis aeruginosa (M. aeruginosa) combined with photocatalysts could synergistically facilitate the photodecontamination of tetracycline hydrochloride (TC) and Cr(VI). In this study, for the first time, harmful algae were successfully converted into photoreactive bionano hybrid materials by immobilizing M. aeruginosa cells onto polyacrylonitrile (PAN)-TiO2/Ag hybrid nanofibers, and their photocatalytic activity was evaluated. The addition of M. aeruginosa significantly improved the photodecontamination, and the reaction rate constant (k) values of TC and Cr(VI) degradation by M. aeruginosa-PAN/TiO2/Ag nanofiber mats were 2.4 and 1.5-fold higher than that of bare PAN/TiO2/Ag nanofiber. Photoreaction caused damage to algae cells, but no microcystin was found that had been photodegraded simultaneously. The effects of various active species were also investigated, and the photodegradation mechanism was proposed. Recycling tests revealed that this flexible M. aeruginosa-PAN/TiO2/Ag hybrid mat had potential application in the removal of mixed organic and inorganic pollutants with high efficiency and without secondary pollutants. Thus, harmful algae blooms could serve as an efficient materials to remove toxic pollutants in a sustainable way under visible light irradiation.

scholarly journals Solar-driven photocatalytic decomposition of microcystin-LR: from laboratory development to on-site demonstration

2017 ◽  
Vol 17 (6) ◽  
pp. 1722-1729 ◽  
Author(s):  
Hesam Zamankhan Malayeri ◽  
Mallikarjuna Nadagouda ◽  
Hyeok Choi
Keyword(s):  
Visible Light ◽  
Real Time ◽  
Tio2 Film ◽  
Organic Contaminants ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
High Efficiency ◽  
Sol Gel ◽  
Photocatalytic Decomposition ◽  
Sol Gel Synthesis

Abstract Harmful algal blooms (HABs) found in various water bodies worldwide have been a huge concern due to their adverse impacts on human health and ecosystems. In particular, HABs associated with cyanobacteria have been of great interest because of their potential to generate and release biological toxins, especially, lethal microcystins (MCs). The overall goal of this study was to develop a new sustainable approach to decompose MCs, preferably on-site and in real-time with minimal effort, fewer chemicals, and low energy inputs. To achieve the goal, a high efficiency nitrogen-doped TiO2 photocatalytic film immobilized onto a glass substrate was fabricated via integrated sol-gel synthesis employing nitrogen-containing surfactants as pore-templating agent and nitrogen-dopant. The film exhibited visible light-activated, nanoporous, and transparent properties. Effects of surfactant type, calcination temperature, coating layers, and reaction pH on the photocatalytic decomposition of microcystin-LR (MC-LR) were investigated under visible light. Eventually, the TiO2 film was able to successfully decompose MC-LR on-site in a lake under solar radiation in real-time. This study implies the high potential of the TiO2 film for on-site and real-time decomposition of many organic contaminants in water by using sustainable solar energy.

Novel three-dimensional macroporous PbO2 foam electrode for efficient electrocatalytic decolorization of dyes

RSC Advances ◽  
2015 ◽  
Vol 5 (109) ◽  
pp. 89363-89367 ◽  
Author(s):  
Tigang Duan ◽  
Ye Chen ◽  
Qing Wen ◽  
Yupeng Cong ◽  
Ying Duan ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
High Efficiency ◽  
Three Dimensional ◽  
Porous Architecture ◽  
Binder Free ◽  
Highly Porous ◽  
Decolorization Of Dyes

3D macroporous PbO2 foam electrode possesses a binder-free and highly-porous architecture, and ensures a high efficiency for degrading organic contaminants.

scholarly journals Enhancement in the rate of nitrate degradation on Au- and Ag-decorated TiO2 photocatalysts

2020 ◽  
Vol 10 (7) ◽  
pp. 2082-2091
Author(s):  
Thomas Caswell ◽  
Mbongiseni W. Dlamini ◽  
Peter J. Miedziak ◽  
Samuel Pattisson ◽  
Philip R. Davies ◽  
...  
Keyword(s):  
Tio2 Photocatalysts ◽  
Hole Scavenger ◽  
Nitrate Degradation

The solar-driven reduction of nitrate to nitrogen has been studied in the presence of a formate hole scavenger, over a series of Au- and Ag-decorated TiO2 catalysts.

scholarly journals Electroporation and genetic supply of Cas9 increase the generation efficiency of CRISPR/Cas9 knock-in alleles in C57BL/6J mouse zygotes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Samy Alghadban ◽  
Amine Bouchareb ◽  
Robert Hinch ◽  
Polinka Hernandez-Pliego ◽  
Daniel Biggs ◽  
...  
Keyword(s):  
Mouse Models ◽  
High Efficiency ◽  
Genetically Modified ◽  
Delivery Methods ◽  
Embryo Survival ◽  
Guide Rnas ◽  
Standard Tool ◽  
Survival And Development ◽  
Effective Delivery ◽  
Mouse Zygotes

Abstract CRISPR/Cas9 machinery delivered as ribonucleoprotein (RNP) to the zygote has become a standard tool for the development of genetically modified mouse models. In recent years, a number of reports have demonstrated the effective delivery of CRISPR/Cas9 machinery via zygote electroporation as an alternative to the conventional delivery method of microinjection. In this study, we have performed side-by-side comparisons of the two RNP delivery methods across multiple gene loci and conclude that electroporation compares very favourably with conventional pronuclear microinjection, and report an improvement in mutagenesis efficiency when delivering CRISPR via electroporation for the generation of simple knock-in alleles using single-stranded oligodeoxynucleotide (ssODN) repair templates. In addition, we show that the efficiency of knock-in mutagenesis can be further increased by electroporation of embryos derived from Cas9-expressing donor females. The maternal supply of Cas9 to the zygote avoids the necessity to deliver the relatively large Cas9 protein, and high efficiency generation of both indel and knock-in allele can be achieved by electroporation of small single-guide RNAs and ssODN repair templates alone. Furthermore, electroporation, compared to microinjection, results in a higher rate of embryo survival and development. The method thus has the potential to reduce the number of animals used in the production of genetically modified mouse models.

scholarly journals Microfluidic Reactors for Plasmonic Photocatalysis Using Gold Nanoparticles

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 869 ◽  
Author(s):  
Huaping Jia ◽  
Yat Lam Wong ◽  
Aoqun Jian ◽  
Chi Chung Tsoi ◽  
Meiling Wang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Visible Light ◽  
Tio2 Film ◽  
Low Cost ◽  
Field Tests ◽  
Reaction Rate Constant ◽  
Strong Absorption ◽  
Electron Hole ◽  
Protective Function ◽  
Potential Applications

This work reports a microfluidic reactor that utilizes gold nanoparticles (AuNPs) for the highly efficient photocatalytic degradation of organic pollutants under visible light. The bottom of microchamber has a TiO2 film covering a layer of AuNPs (namely, TiO2/AuNP film) deposited on the F-doped SnO2 (FTO) substrate. The rough surface of FTO helps to increase the surface area and the AuNPs enables the strong absorption of visible light to excite electron/hole pairs, which are then transferred to the TiO2 film for photodegradation. The TiO2 film also isolates the AuNPs from the solution to avoid detachment and photocorrosion. Experiments show that the TiO2/AuNP film has a strong absorption over 400–800 nm and enhances the reaction rate constant by 13 times with respect to the bare TiO2 film for the photodegradation of methylene blue. In addition, the TiO2/AuNP microreactor exhibits a negligible reduction of photoactivity after five cycles of repeated tests, which verifies the protective function of the TiO2 layer. This plasmonic photocatalytic microreactor draws the strengths of microfluidics and plasmonics, and may find potential applications in continuous photocatalytic water treatment and photosynthesis. The fabrication of the microreactor uses manual operation and requires no photolithography, making it simple, easy, and of low cost for real laboratory and field tests.

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