Degradation of malachite green by a pulsed light/H2O2 process

2019 ◽  
Vol 79 (2) ◽  
pp. 260-269 ◽  
Author(s):  
Patricia Navarro ◽  
Jean Pier Zapata ◽  
Gemma Gotor ◽  
Rafael Gonzalez-Olmos ◽  
Vicente M. Gómez-López

Abstract Pulsed light (PL) is a type of photonic technology characterized by intense short light pulses that enhance the speed of photochemical reactions, and which might be useful as light source in advanced oxidation processes. This work aimed to test PL as light source for the degradation of the dye malachite green (MG) by combining PL with H2O2. To this end, the effect of dye and H2O2 concentrations and pH on the degradation rate of MG was studied and a degradation pathway was proposed. Dye degradation followed a pseudo-first order kinetics; it increased with low initial dye concentration, high H2O2 concentration and low pH. Complete decolourization was achieved after 35 light pulses (75 J/cm2), with a degradation rate of 0.0710 cm2/J. The degradation was initiated by the attack of hydroxyl radicals to the central carbon of MG generating 4-(dimethylamino)benzophenone (DLBP) followed by the addition of hydroxyl radicals to the non-amino aromatic ring of DLBP and the demethylation of the amino group. Results indicate that PL technology has potential to be implemented to decrease the environmental impact of dyeing industries.

2014 ◽  
Vol 587-589 ◽  
pp. 578-581
Author(s):  
Jin Zhu ◽  
Chang Ping Zhu ◽  
Bin Wang ◽  
Run Hang Gong ◽  
Qing Gong Ren ◽  
...  

The degradation of chlorpyrifos is investigated with the treatments of sonolysis, ozonolysis, and sonolytic ozonolysis at various frequencies. Results show that there exists frequency effect in sonolytic ozonolysis. In sonolytic ozonolysis, the maximum degradation rate is obtained at 495 kHz, and the degradation kinetics is fitted to the first-order kinetics model well. However, the most significant synergistic effect between ultrasonic and ozone is at 124 kHz. The kinetics parameters indicate that chlorpyrifos is much more labile to ultrasonic at 495 kHz, while ozone is much more soluble at 124 kHz. The hydrolysis and oxidation are deduced to contribute to the degradation reaction and the degradation pathway for chlorpyrifos degradation is proposed.


2013 ◽  
Vol 67 (5) ◽  
pp. 1097-1104 ◽  
Author(s):  
P. Manoj Kumar Reddy ◽  
B. Ramaraju ◽  
Ch. Subrahmanyam

Oxidative decomposition of aqueous organic pollutant malachite green (MG) was studied in a dielectric barrier discharge reactor operated under ambient conditions. Total organic carbon content analysis confirmed the mineralization of the pollutant leading to the formation of carbon dioxide, which was confirmed by an infrared analyzer. Typical results indicated that the degradation rate increases with increasing applied voltage and decreases with increasing concentration. Dye degradation followed first order kinetics. The intermediate products formed during the degradation of MG were identified by a high resolution mass spectrometer (HR-MS) and proposed a plausible mechanism for the mineralization process.


TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 167-178 ◽  
Author(s):  
Xin Tong ◽  
Jiao Li ◽  
Jun Ma ◽  
Xiaoquan Chen ◽  
Wenhao Shen

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.


Author(s):  
Manmeet Kaur ◽  
Suman Prajapati ◽  
Samneek Cholia ◽  
Jaskeet Singh Mann ◽  
Gurpreet Singh

Background: In the recent years, the green synthesis of nanoparticles has taken a lead role over the conventional chemical and physical approach due to its non-toxic, cost effective parameters and has found its place in various applications. Objectives: The major objectives of this study was to synthesise and characterize the copper nanoparticles using the rose extract at different set of conditions and analyse these nanoparticles as a source of dye degradation agent under sunlight conditions. Methods: Present study was conducted with the aim to synthesis the copper nanoparticle using the rose petal extract. The components present the in the extract act as the reduction and stabilization agents for the synthesis of CuNPs. The synthesized nanoparticles were characterized by using UV-VIS, FTIR, XRD and SEM analysis. Photocatalytic degradation of two dyes (Malachite Green and Carbol fuchsin) was analysed using double beam spectroscopic analysis Results: UV-Vis analysis indicated the presence of a peak at around 630 nm. The FT-IR analysis indicated the involvement of various biomolecules during the synthesis of nanoparticles. The structure and the conformation was elucidated using XRD and SEM showed the agglomerated form of the synthesized nanoparticles with the size range of about 60-90 nm. The synthesised copper nanoparticles was used for degradation of malachite green and carbol fuchsin dye using photocatalytic under sunlight irradiation. UV-Vis spectral analysis indicated that synthesised copper nanoparticle act more effective in degradation of malachite green (around 95%) whereas carbol fuchsin showed a maximum degradation by 52% therefore suggesting that CuNPs act as an efficient photo catalyst in dye degradation. Conclusion: The results obtained from this study indicates that rose extract has the potential of synthesis of copper nanoparticles which is non-toxic and convenient approach as compared to physical and chemical synthesis. These nanoparticles can be effectively employed as dye decolourization agents to treat industrial effluent and prevent the environmental pollution.


2020 ◽  
Vol 10 (6) ◽  
pp. 849-859
Author(s):  
Radwa A. El-Salamony ◽  
Abeer A. Emam ◽  
Nagwa A. Badawy ◽  
Sara F. El-Morsi

Objective: ZnO nanoparticles were synthesized using wet impregnation method, and activated carbon from rice straw (RS) prepared through chemical route. Methods: The nano-composites ZnO-AC series were prepared with different ZnO:AC ratio of 10, 20, 50, and 70% to optimize the zinc oxide nanoparticles used. The obtained composites were characterized by FE-SEM, XRD, SBET, and optical techniques then used for the photo-degradation of Malachite green dye (MG) under visible light. Results: It was found that 10ZnO-AC exhibited excellent visible light photo-catalytic performance. The ·OH radicals’ formation is matching with photo-activity of the prepared composites. The photo-degradation efficiency of MG increased from 63% to 93%, when the 10ZnO-AC photocatalyst amount was increased from 0.5 to 6 g/L. Conclusion: The GC-MS technique was used to analyze the intermediates formed; up to 15 kinds of chemicals were identified as the degradation products.


2018 ◽  
Vol 6 (4) ◽  
pp. 327-331
Author(s):  
Dipesh Shahi ◽  
Rajiv Sapkota

The use of different dyes and pigments is increasing with the increase in industrialization leading to the high production of effluent. The effluent contaminated with dyes and dye-stuff has harmful effects on public health and the environment. Thus, the treatment of effluent is essential. Biological approaches are gaining much interest due to their cost-effective and eco-friendly nature over various physicochemical methods for the treatment of dye-contaminated wastewater. This study highlights on the biodegradation of congo red and malachite green by using leaf and root extracts of Parthenium hysterophorus. The extract and the dye were mixed in the ratio of 1:2 and incubated at 40ºC for 90 minutes. Decolorization assay was performed using UV visible spectrophotometer which indicated that decolorization was due to degradation of dyes into non-colored metabolites. The leaves extract exhibited higher decolorizing activity than roots extract. The maximum decolorization for leaves extract was 55.8% (congo red) and 51.6% (malachite green). Furthermore, phytotoxicity test was carried out to determine the effect of dyes and their degradation metabolites on seed germination and seedling growth of chickpea (Cicer arietinum L). The germination percentage and seedling growth were more in degradation metabolites than untreated dyes, indicating less toxic nature of degradation metabolites. Hence, it can be inferred that P. hysterophorus extracts can be used to treat dye wastewater and treated wastewater can be used for irrigation. Int. J. Appl. Sci. Biotechnol. Vol 6(4): 327-331


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