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 ◽  
...  

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.

2013 ◽  
Vol 67 (6) ◽  
pp. 1260-1271 ◽  
Author(s):  
I. Michael ◽  
E. Hapeshi ◽  
C. Michael ◽  
D. Fatta-Kassinos

The overall aim of this work was to examine the degradation of trimethoprim (TMP), which is an antibacterial agent, during the application of two advanced oxidation process (AOP) systems in secondary treated domestic effluents. The homogeneous solar Fenton process (hv/Fe2+/H2O2) and heterogeneous photocatalysis with titanium dioxide (TiO2) suspensions were tested. It was found that the degradation of TMP depends on several parameters such as the amount of iron salt and H2O2, concentration of TiO2, pH of solution, solar irradiation, temperature and initial substrate concentration. The optimum dosages of Fe2+ and H2O2 for homogeneous ([Fe2+] = 5 mg L−1, [H2O2] = 3.062 mmol L−1) and TiO2 ([TiO2] = 3 g L−1) for heterogeneous photocatalysis were established. The study indicated that the degradation of TMP during the solar Fenton process is described by a pseudo-first-order reaction and the substrate degradation during the heterogeneous photocatalysis by the Langmuir–Hinshelwood kinetics. The toxicity of the treated samples was evaluated using a Daphnia magna bioassay and was finally decreased by both processes. The results indicated that solar Fenton is more effective than the solar TiO2 process, yielding complete degradation of the examined substrate within 30 min of illumination and dissolved organic carbon (DOC) reduction of about 44% whereas the respective values for the TiO2 process were ∼70% degradation of TMP within 120 min of treatment and 13% DOC removal.


2021 ◽  
Vol 16 (2) ◽  
Author(s):  
Satish Chandra Sati ◽  
Ankit Singh Bartwal ◽  
Sumit Ringwal ◽  
Gurpreet Kour ◽  
Rashmi Rawat ◽  
...  

Nowadays, silver nano-compounds mediated by plant materials are widely used material in daily life chemistry as well as across the industries, medical, electronics, ceramics, and in all research fields, because it has some specific characteristics such as non-toxic, inexpensive, nature-friendly, heat resistant, catalytic activity, high electric conductivity and so on. In the present work we reported the photo-catalytic dye degradation of green synthesized silver nanoparticles of size 43.75 nm by using the flowers extract of Rhododendron campanulatum tree. Synthesized AgNPs have worked as a strong nano-catalyst for the degradation of toxic dyes such as malachite green (MG), and acridine orange (AO). As a catalyst, synthesized AgNPs degraded the malachite green (MG) dye 47.22 % within 90 min, and acridine orange (AO) dye 66.16 % in 4 h of solar irradiation, while in the absence of nanocatalyst, MG and AO dye degraded upto 22.13 % in 90 min and 46.75 % in 4 h of photo-irradiation respectively. Synthesized nano material (AgNPs) may be applicable as a strong catalytic agent for the degradation of toxic dyes, water purifying agent as well as a good antioxidant agent.


Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 242
Author(s):  
Idrees Khan ◽  
Khalid Saeed ◽  
Ivar Zekker ◽  
Baoliang Zhang ◽  
Abdulmajeed H. Hendi ◽  
...  

The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.


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.


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 ◽  
...  

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.


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


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xiujuan Qin ◽  
Li Cui ◽  
Guangjie Shao

Ti-doped ZnO sol-composite films were prepared on the glass substrate by the two-step sol-gel technique. X-ray diffraction, Uv-Vis spectrophotometer, and FS spectrum of composite films were used to help make structure characterization and optical performance testing. The results showed that the composite was a mixture of ZnO + Zn2TiO4. Because of synergistic effect of both semiconductor oxides, composite films had a wide range of spectral response in the visible region, and the absorption band edge was about 510 nm, and the Green Belt of composite films luminous significantly enhanced. Photocatalytic oxidation experiments showed that using the composite films treatment (16.5 ml, l0 mg/L methyl orange aqueous solution)/cm2, the decolorization rate of methyl-orange was 90% after 3 hours irradiation.


Author(s):  
Amaia Menendez ◽  
Jose Ignacio Lombraña ◽  
Ana de Luis

AbstractSynthetic dyes are extensively used in textile dyeing, paper printing, colour photography, pharmaceuticals, food, cosmetics and other industries. In spite of their diversity there are a certain number of properties common to many dye compounds, such as aromatic constitution, chromophore groups and others. Similarly to other dyes and due to the formation of colour intermediates, in the case of Rhodamine 6G colour capacity is maintained in the initial steps of dye degradation. For this reason in the degradation of a dye it is necessary to distinguish between two processes that take place simultaneously: dye removal and decolourization. This study was conducted by using a water solution of 50 mg/L of Rhodamine 6G (Rh-6G), as a model of a dye wastewater, in the hydrogen peroxide/UV system. The kinetic model proposed in this paper for the removing of Rh- 6G is a sequential first-order reaction. This model describes acceptably the changes in two kinds of compound for a wide interval of H


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