Photocatalytic oxidation of high concentrated dye solutions enhanced by hydrodynamic cavitation in a pilot reactor

Abstract Tests for the photocatalytic degradation of solutions of three reactive dyes, Red M-5B, Procion Blue MX-R and Procion Black H-N, in the presence of H2O2 were carried out. When the solutions of the three reactive dyes were irradiated by UV or solar light, the colour of the solutions disappeared gradually. A statistical analysis of the test results indicated a linear relation between the concentration of dyes and the time of irradiation. The discolouration reaction of the solutions was of the first order. Rate equations for the discolouration reactions of dye solutions were developed. The dark reactions or the dye solutions containing H2O2 were very slow, illustrating that the photochemical reaction played a very important role. It was demonstrated that UV light and solar light (300 to 380 nm) photolyzes the HO and that the resulting OH radical reacts with the dye molecules and destroys the chromophore.

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Treatment of fish processing industry wastewater using hydrodynamic cavitational reactor with biodegradability improvement

Water Science & Technology ◽

10.2166/wst.2020.049 ◽

2019 ◽

Vol 80 (12) ◽

pp. 2310-2319 ◽

Cited By ~ 2

Author(s):

Prashant Dhanke ◽

Sameer Wagh ◽

Abhijeet Patil

Keyword(s):

Organic Matter ◽

New Technology ◽

Oxygen Demand ◽

Operating Conditions ◽

Hydrodynamic Cavitation ◽

Inlet Pressure ◽

Fish Processing ◽

Processing Industry ◽

Cavitation Effect ◽

Processing Plants

Abstract Water generated from the fish processing industry is contaminated with organic matter. This organic matter present in wastewater increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD). A new technology, hydrodynamic cavitation (HC) is used to deal with this wastewater produced in fish processing plants. The orifice plate is used in the HC reactor to generate a cavitation effect. The intensification of this technique was carried out with the help of hydrogen peroxide (H2O2) and TiO2. The treatment of this wastewater is reported in terms of percent degradation in BOD and COD and in biodegradability index (BI). Operating parameters like inlet pressure, pH, operating temperature and H2O2 doses were used to find the optimum condition. 15 g/L of H2O2 gave 69.5% reduction of COD in the 120 min of treatment that also increases BI value to 0.93 at inlet pressure 8 bar, Plate-5, temperature (30 °C), and pH 4. In the ultrasonic cavitation (UC) reactor, COD reduction is 68.7% without TiO2 and with TiO2 it is 71.2%. Also, this HC and UC reactor reduced CFU count to a great extent at the same operating conditions.

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Modeling of photocatalytic oxidation reactor for methyl ethyl ketone removal from indoor environment: Systematic model development and validation

Chemical Engineering Journal ◽

10.1016/j.cej.2020.128265 ◽

2021 ◽

Vol 409 ◽

pp. 128265

Author(s):

Mojtaba Malayeri ◽

Chang-Seo Lee ◽

Fariborz Haghighat

Keyword(s):

Methyl Ethyl Ketone ◽

Indoor Environment ◽

Photocatalytic Oxidation ◽

Model Development ◽

Methyl Ethyl ◽

Oxidation Reactor ◽

Development And Validation

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Photocatalytic Pretreatment of Commercial Lignin Using TiO2-ZnO Nanocomposite-Derived Advanced Oxidation Processes for Methane Production Synergy in Lab Scale Continuous Reactors

Catalysts ◽

10.3390/catal11010054 ◽

2021 ◽

Vol 11 (1) ◽

pp. 54

Author(s):

Yu-Ming Chu ◽

Hafiz Muhammad Asif Javed ◽

Muhammad Awais ◽

Muhammad Ijaz Khan ◽

Sana Shafqat ◽

...

Keyword(s):

Photocatalytic Oxidation ◽

Advanced Oxidation Processes ◽

Synergistic Effects ◽

Oxidation Products ◽

Methane Yield ◽

Zno Nanoparticle ◽

Coumaric Acid ◽

Stirred Tank Reactors ◽

Lignin Oxidation ◽

Constant Operation

The photocatalytic pretreatment of lignocellulosic biomass to oxidize lignin and increase biomass stability has gained attention during the last few years. Conventional pretreatment methods are limited by the fact that they are expensive, non-renewable and contaminate the anaerobic digestate later on. The present study was focused to develop a metal-derived photocatalyst that can work with visible electromagnetic spectra light and oxidize commercial lignin liquor. During this project the advanced photocatalytic oxidation of lignin was achieved by using a quartz cube tungsten T3 Halogen 100 W lamp with a laboratory manufactured TiO2-ZnO nanoparticle (nanocomposite) in a self-designed apparatus. The products of lignin oxidation were confirmed to be vanillic acid (9.71 ± 0.23 mg/L), ferrulic acid (7.34 ± 0.16 mg/L), benzoic acid (6.12 ± 0.17 mg/L) and p-coumaric acid (3.80 ± 0.13 mg/L). These all products corresponded to 85% of the lignin oxidation products that were detectable, which is significantly more than any previously reported lignin pretreatment with even more intensity. Furthermore, all the pretreatment samples were supplemented in the form of feedstock diluent in uniformly operating continuously stirred tank reactors (CSTRs). The results of pretreatment revealed 85% lignin oxidation and later on these products did not hinder the CSTR performance at any stage. Moreover, the synergistic effects of pretreated lignin diluent were seen that resulted in 39% significant increase in the methane yield of the CSTR with constant operation. Finally, the visible light and nanoparticles alone could not pretreat lignin and when used as diluent, halted and reduced the methane yield by 37% during 4th HRT.

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