Mechanistic Understanding of Heterogeneous Photocatalysis for the Dye Degradation in Wastewater

2020 ◽  
pp. 283-304
Author(s):  
Sahil Thareja
Keyword(s):  
Dye Degradation ◽  
Heterogeneous Photocatalysis ◽  
Mechanistic Understanding

scholarly journals Titanium dioxide immobilization in recycled aluminum net for degradation of textile dye by Heterogeneous Photocatalysis trough neural networks

2019 ◽  
Vol 23 ◽  
pp. 27
Author(s):  
Ingrid Larissa da Silva Santana ◽  
Ada Azevedo Barbosa ◽  
Marina Gomes Silva ◽  
Ramon Vinicius Santos de Aquino ◽  
Naiana Santos da Cruz Santana Neves ◽  
...  
Keyword(s):  
Dye Degradation ◽  
Film Formation ◽  
Supported Catalyst ◽  
Absolute Error ◽  
Heterogeneous Photocatalysis ◽  
Textile Dye ◽  
Degradation Kinetic ◽  
Tio2 Anatase ◽  
Degradation Rates ◽  
Golden Yellow

In this work, aluminum net crafted (recycled) were used as TiO2 support for the treatment of textile dye Remazol golden yellow (RGY 150). The immobilization of 200mg of TiO2 was accomplished after aluminum net calcination. The following experiments were carried out in a photocatalytic bench reactor: preliminary tests, a 23 factorial experimental design with best system and the degradation kinetic in systems with TiO2 supported on aluminum net.It was observed characteristic peaks of aluminum and TiO2 (anatase and rutile) by XRD and the catalyst film formation was verified by SEM. The system UV/H2O2/TiO2 performed higher efficiency, with 99% of dye degradation in 50 minutes, followed by the system UV/H2O2/TiO2sp with 93% of dye degradation. Whereas the supported catalyst presents execution advantages and high degradation rates, the factorial design was realized for this system, displaying best degradation (100% degradation in 35 minutes). It was obtained k = 0.114 min-1 and R² = 0.994 in a pseudo-first-order model adjustment system. The use of artificial neural network was proven to be efficient to predict the degradation of a textile dye, with an absolute error of 0.0181. After treatment, there was a decrease of dye toxicity.

scholarly journals Dye Degradation Enhanced by Coupling Electrochemical Process and Heterogeneous Photocatalysis

2015 ◽  
Author(s):  
Lidiaine M. Santos ◽  
Kamila P. de Amorim ◽  
Leonardo S. Andrade ◽  
Paulo S. Batista ◽  
Alam G. Trovó ◽  
...  
Keyword(s):  
Dye Degradation ◽  
Heterogeneous Photocatalysis ◽  
Electrochemical Process

Decolorization and mineralization of reactive dyes by a photocatalytic process using ZnO and UV radiation

2012 ◽  
Vol 66 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Wilson N. Almeida Guerra ◽  
Joana M. Teixeira Santos ◽  
Lucia R. Raddi de Araujo
Keyword(s):  
Dye Degradation ◽  
Research Work ◽  
Reactive Dyes ◽  
Textile Wastewater ◽  
Heterogeneous Photocatalysis ◽  
Crystal Field Theory ◽  
Zero Order Kinetics ◽  
Vis Spectroscopy ◽  
Effective Option ◽  
Low Efficiency

Reactive dyes are one of the major pollutants in textile wastewater and a concern because they are not easily degraded by conventional wastewater treatments. Heterogeneous photocatalysis has been considered an effective option for treating wastewater containing those dyes. This research work assesses the photocatalytic degradation of reactive dyes using UV irradiation and pure or impregnated ZnO. In addition to photocatalysis, separate photolysis and adsorption experiments were conducted but showed low efficiency. The dye degradation was monitored by UV–Vis spectroscopy and mineralization was determined by total organic carbon (TOC) analyses. Total color removal was achieved after 30 min of irradiation using pure ZnO. The Black 5 dye photocatalytic decolorization reaction followed first-order kinetics, while Yellow 145, Red 4 and Blue 21 dyes followed zero-order kinetics. TOC removals in the range of 70–80% were achieved after 240 min of individual photocatalytic treatment with ZnO. The performance of each photocatalyst was also compared when the four dyes were mixed together and the order of efficiency in the mineralization process was as follows: Fe/ZnO > ZnO > Co/ZnO. This result was explained by the crystal field theory.

Kinetic-invariant analysis of dye degradation in an annular slurry bubble-column photo reactor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guncha Munjal ◽  
Ashok N. Bhaskarwar ◽  
Amita Chaudhary
Keyword(s):  
Bubble Column ◽  
Dye Degradation ◽  
Heterogeneous Photocatalysis ◽  
Aeration Rate ◽  
Bubble Column Reactor ◽  
Catalyst Loading ◽  
Semiconductor Surface ◽  
Reactor Performance ◽  
Photocatalytic Reactor ◽  
Slurry Bubble Column

Abstract Heterogeneous photocatalysis refers to the series of oxidation and reduction reactions on a semiconductor surface by the electrons and holes generated by absorption of light by the catalyst. This method is widely used for the degradation of dyes and their mixtures present in the textile effluent, and involves two main aspects, viz. a photocatalyst, and a photoreactor. TiO2 nanoparticles are well explored and among the best known photocatalysts used worldwide. Annular slurry bubble-column reactor is a commonly used photoreactor for dye(s) degradation. This research paper explores the effects of different parameters like air-flow rate, photocatalyst loading, and initial dye concentration on the dye degradation in an annular slurry bubble-column photoreactor. The results showed that the best dye degradation efficiencies were reported at an aeration rate of 1.7 × 10−4 m3/s and at a catalyst loading of 1.5 kg/m3. Higher the initial concentration of dye, the greater is the time taken for complete degradation and mineralization. A kinetic-invariant method, which is based on the dimensionless representation of existing data to predict the new experimental results, is used to develop a semi-empirical reactor performance equation. It can be used to predict the concentration of dye undergoing degradation in the photocatalytic reactor at any time without a need for further experimentation.

scholarly journals An Overview: Recent Development of Titanium Oxide Nanotubes as Photocatalyst for Dye Degradation

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Chin Wei Lai ◽  
Joon Ching Juan ◽  
Weon Bae Ko ◽  
Sharifah Bee Abd Hamid
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Textile Industry ◽  
Organic Dyes ◽  
Dye Degradation ◽  
High Surface ◽  
High Surface Area ◽  
Living Organism ◽  
Heterogeneous Photocatalysis ◽  
Titanium Oxide Nanotubes

Today, organic dyes are one of the largest groups of pollutants release into environment especially from textile industry. It is highly toxic and hazardous to the living organism; thus, the removal of these dyes prior to discharge into the environment is essential. Varieties of techniques have been employed to degrade organic dyes and heterogeneous photocatalysis involving titanium dioxide (TiO2) appears to be the most promising technology. In recent years, TiO2nanotubes have attracted much attention due to their high surface area and extraordinary characteristics. This paper presents a critical review of recent achievements in the modification of TiO2nanotubes for dye degradation. The photocatalytic activity on dye degradation can be further enhanced by doping with cationic or anionic dopant.

scholarly journals Degradation of Malachite green using heterogeneous nanophotocatalysts (NiO/TiO2, CuO/TiO2) under solar and microwave irradiation

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Chafia Djebbari ◽  
Emna zouaoui ◽  
Nesrine Ammouchi ◽  
Chafika Nakib ◽  
Daoiya Zouied ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Malachite Green ◽  
Photocatalytic Oxidation ◽  
Advanced Oxidation Process ◽  
Dye Degradation ◽  
Aqueous Suspension ◽  
Heterogeneous Photocatalysis ◽  
Solar Irradiation ◽  
Wide Range ◽  
Catalyst Type

AbstractHeterogeneous photocatalysis is an advanced oxidation process (AOP). This technique is used to degrade a wide range of pollutants in water. In this study, photocatalytic oxidation and mineralization of malachite green in an aqueous suspension containing nickel-based catalysts and copper supported on TiO2 prepared by wet diffusional impregnation was studied using two sources of irradiation: solar and microwave. Photodegradation kinetics were studied according to several parameters, such as catalyst type, dye concentration, photocatalyst mass and microwave power. The results showed that the photodegradation of malachite green is faster in the presence of CuO/TiO2 catalyst than NiO/TiO2 catalyst than TiO2. Dye degradation by microwave irradiation is faster than that by solar irradiation.

scholarly journals Performance Evaluation of the SrZrxSn1-xO3 Photocatalytic System for Remazol Yellow Dye Degradation Employing Box-Behnken Design

2021 ◽  
Vol 10 (2) ◽  
pp. e48610212328
Author(s):  
Yohanna Ribeiro Klafke ◽  
Mayara Macedo da Mata ◽  
Ieda Maria Garcia dos Satos ◽  
Mary Cristina Ferreira Alves ◽  
Simone da Silva Simoes
Keyword(s):  
Dye Degradation ◽  
Large Family ◽  
Heterogeneous Photocatalysis ◽  
Textile Dyes ◽  
Chemical Processes ◽  
Box Behnken Design ◽  
Structural Modifications ◽  
Photocatalytic System ◽  
Golden Yellow ◽  
By Products

Contamination of effluents often occurs due to improper disposal of textile dyes or their by-products. These can often be carcinogenic and/or mutagenic to the biome. Given the above, the need for effective methods for treating effluents is clear. This treatment occurs by biological, physical, and/or chemical processes. Regarding chemical processes, heterogeneous photocatalysis stands out, mainly because it guarantees an effective degradation of contaminants. In this sense, mixed metal oxides, act as photocatalysts and constitute structures capable of producing a large family of solids with physical properties suitable for the degradation of many pollutants. Modified ABO3 perovskites, as in the case of the SrZrxSn1-xO3 semiconductor system, are effective in the degradation of textile dyes in effluents. The present work aimed to use the Box-Behnken model to evaluate the performance of the oxides resulting from the structural modifications of the perovskite SrZrxSn1-xO3 system, concerning the discoloration of the golden yellow dye remazol. The synthesized oxides were characterized by instrumental techniques and a Box-Behnken 34 project was developed. From this, the influence of some factors such as structural modification, oxide mass, exposure time, and the number of UVC lamps was evaluated. The discoloration of the dye was monitored from the attenuation of the absorbance at the wavelength 411 nm. According to the results obtained, the highest percentage of discoloration was obtained using the modified oxide SrZr0,25Sn0,75O3 for an approximate time of 6 hours in contact with 1 UVC lamp.

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