dye pollutants
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2022 ◽  
Vol 2022 ◽  
pp. 1-18
Author(s):  
Avvaru Praveen Kumar ◽  
Dinesh Bilehal ◽  
Tegene Desalegn ◽  
Shalendra Kumar ◽  
Faheem Ahmed ◽  
...  

Degradation of dye pollutants by the photocatalytic process has been regarded as the most efficient green method for removal organic dyes from contaminated water. The current research work describes the synthesis of Fe3O4@SiO2@Ru hybrid magnetic composites (HMCs) and their photocatalytic degradation of two azo dye pollutants, methyl orange (MO) and methyl red (MR), under irradiation of visible light. The synthesis of Fe3O4@SiO2@Ru HMCs involves three stages, including synthesis of Fe3O4 magnetic microspheres (MMSs), followed by silica (SiO2) coating to get Fe3O4@SiO2 MMSs, and then incorporation of presynthesized Ru nanoparticles (~3 nm) onto the surface of Fe3O4@SiO2 HMCs. The synthesized HMCs were characterized by XRD, FTIR, TEM, EDS, XPS, BET analysis, UV-DRS, PL spectroscopy, and VSM to study the physical and chemical properties. Furthermore, the narrow band gap energy of the HMC photocatalyst is a significant parameter that provides high photocatalytic properties due to the high light adsorption. The photocatalytic activity of synthesized Fe3O4@SiO2@Ru HMCs was assessed by researching their ability to degrade the aqueous solution of MO and MR dyes under visible radiation, and the influence of various functional parameters on photocatalytic degradation has also been studied. The results indicate that the photocatalytic degradation of MO and MR dyes is more than 90%, and acid media favors better degradation. The probable mechanism of photodegradation of azo dyes by Fe3O4@SiO2@Ru HMC catalysts has been proposed. Furthermore, due to the strong ferromagnetic Fe3O4 core, HMCs were easily separated from the solution after the photocatalytic degradation process for reuse. Also, the photocatalytic activity after six cycles of use is greater than 90%, suggesting the stability of the synthesized Fe3O4@SiO2@Ru HMCs.


Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 64
Author(s):  
Yuanzhi Min ◽  
Gao Song ◽  
Ling Zhou ◽  
Xinyue Wang ◽  
Pingying Liu ◽  
...  

Nanostructured noble metal-semiconductor materials have been attracting increasing attention because of their broad application in the field of environmental remediation, sensing and photocatalysis. In this study, a facile approach for fabricating silver@mesoporousanataseTiO2 (Ag@mTiO2) core-shell nanoparticles employing sol-gel and hydrothermal reaction is demonstrated. The Ag@mTiO2nanoparticles display excellent surface-enhanced Raman scattering (SERS) sensitivity and they can detect the methylene blue (MB) molecules with the concentration of as low as 10−8 M. They also exhibit outstanding photocatalytic activity compared with mTiO2, due to the efficient separation and recombination restrain of electron–hole pairs under ultraviolet light. The Ag@mTiO2nanoparticles also present good stability and they can achieve recyclable photocatalytic degradation experiments for five times without loss of activity. Subsequently, the nanoparticles with dual functions were successfully used to in situ monitor the photodegradation process of MB aqueous solution. These results, demonstrating the multifunctional Ag@mTiO2 nanoparticles, hold promising applications for simultaneous SERS analysis and the removal of dye pollutants in environmental field.


Author(s):  
Zahra Salmanzadeh-Jamadi ◽  
Aziz Habibi-Yangjeh ◽  
Shima Rahim Pouran ◽  
Xuefei Xu ◽  
Chundong Wang

Abstract The emergence of persistent organic pollutants such as dyes and pharmaceuticals in the aquatic environment has created drastic concerns worldwide due to their toxicity and potential hazards to the environment. Accordingly, non-stoichiometric TiO2/Bi5O7Br nanocomposites were prepared by stirring method as a visible-light-effective photocatalyst for degradation of amoxicillin (AMX) and tetracycline (TC), as antibiotic pollutants, and Rhodamine B (RhB), methylene blue (MB), and malachite green (MG), as dye pollutants. The physiochemical properties of the samples were studied using FESEM, TEM/HRTEM, XRD, EDX, UV–vis DRS, FT-IR, XPS, BET, PL, photocurrent, and EIS analyses. The TiO2/Bi5O7Br (40%) photocatalyst performed superior to TiO2, Bi5O7Br, and TiO2/BiOBr (40%) in photodegradation of the studied contaminants. The degradation rate constants of AMX, TC, MG, RhB, and MB over the TiO2/Bi5O7Br (40%) photocatalyst were 18.2‒32.5-folds greater than pure TiO2, 1.6‒17.3 times higher than pure Bi5O7Br, and 1.4‒13 times larger than TiO2/BiOBr (40%), respectively. Quenching studies showed that superoxide anion radicals and holes had major roles in photocatalytic elimination of TC. Importantly, TiO2/Bi5O7Br (40%) nanocomposite showed robust reusability with high degree of TC removal after four successive photocatalytic recycles. This research introduces a cost-effective, efficient, and reusable visible-light-triggered binary system based on TiO2 for decontamination of medicinal and dye polluted wastewaters.


2021 ◽  
Author(s):  
Imene Hocini ◽  
Khaled Benabbas ◽  
Nabila Khellaf ◽  
Hayet Djelal ◽  
Abdeltif Amrane

Abstract We report the biodegradation of dye pollutants by a green process that combines the microbial activity of activated sludge with phytoremediation ability of the aquatic plant L. gibba. The obtained results showed that the combination of the two processes when the pollutant was present at concentration of 50 mg/L, lead to a dye removal of 95 and 70% for VB-20 and DR-89, respectively. The biodegradability index based on COD and BOD5 measurement was equal to 3.1 for DR-89 and 2.0 for VB-20, confirming that DR-89 was removed by biosorption phenomena and only VB-20 was transformed into biodegradable compounds. UV-visible, FT-IR and LC/MS analysis were used as a tool for the monitoring of the biodegradation metabolite and the results showed that VB-20 biodegradation occurred by the cleavage of anthraquinone cycle and transformation of aromatic compounds to light hydrocarbon chain; this was further confirmed by the calculation of Fukui index using DFT method. This study highlighted the synergy between the phytoremediation and biodegradation process for organic dye removal.


Author(s):  
Qin Li ◽  
Deshuai Yu ◽  
Chaoyu Fan ◽  
Qiaoling Huang ◽  
Yonghua Tang ◽  
...  

2021 ◽  
Vol 55 (9-10) ◽  
pp. 1143-1152
Author(s):  
NUREDIN MUHAMMED ◽  
◽  
GASHAW AZENE ◽  
MELKIE GETNET ◽  
◽  
...  

Water hyacinth (Eichhornia crassipes) (WH) is an invasive plant floating freely on the water, which is widely spread in tropical and subtropical regions. The plant is characterized by high porosity and a high number of functional groups, such as hydroxyl (-OH), carboxyl (–COOH), and amino groups (–NH2). Activated carbon, which is widely accepted on an industrial level for the adsorption of dyes from wastewaters, is a highly expensive material. Thus, in this research, a bioadsorbent material was prepared based on WH biomass and investigated as an alternative tool for water quality remediation, in the case of dye pollutants (RR HE3B). The WH plants were collected from the nearby Lake Tana and used as an adsorbent material without chemical treatment. The batch adsorption test was performed by varying the pH of the solution, adsorbent dosage and initial dye concentration. The powdered WH and RR HE3B dye loaded WH were characterized using FTIR, revealing the emergence of new stretching vibration peaks in the range from 2800 to 3000 cm-1 on the spectrum of Reactive Red HE3B (RR HE3B) dye loaded WH, confirming that -CH and -CH2 were responsible for the adsorption. The analysis of the adsorption isotherm and of the suitability of different models for describing it has led to the following order: Freundlich > Langmuir > Temkin > Dubinin-Radushkevich, based on their correlation coefficient value. This implies that the WH adsorbent surface is heterogeneous and the adsorption of the dye onto it depends not only on the specific reaction sites, as the n-value of the Freundlich constant confirms that the physical adsorption process might be favored. Therefore, WH could be a potential alternative adsorbent to remove the RR HE3B dye from dye polluted wastewaters.


2021 ◽  
Vol 400 (1) ◽  
pp. 2100201
Author(s):  
Arjun S. Chavan ◽  
Bhagvan V. Jadhav ◽  
Mohan R. Kadam ◽  
Akush V. Mali ◽  
C. B. Mane ◽  
...  

Author(s):  
xiaojiao yu ◽  
Qinggong Ji ◽  
Yuchen Wei ◽  
Zongbin Liu ◽  
Ningning Zhao ◽  
...  

Abstract IIn this paper, a codeposition method is used to prepare ZnO/Cu2O composite film with a heterojunction structure in one step. The microstructure and photoelectric properties of the prepared ZnO/Cu2O composite film are characterized and analyzed, and its photocatalytic performance is evaluated. Compared with pure the Cu2O film, the composite film exposes more (111) crystal planes, and has a smaller impedance and a larger photocurrent and open circuit voltage value. These findings indicate that the ZnO/Cu2O composite film exhibits excellent photogenerated carrier separation and migration efficiencies. Among the prepared samples, M2 demonstrates the highest photocatalytic and recycling performance. The calculation of the band position shows that the Fermi level of the composite film exhibits a significant shift compared to that of the pure Cu2O film. The analysis shows that the decrease in the recombination probability of photogenerated carriers caused by the shift of the Fermi level and formation of an internal electric field is the main factor for the significant enhancement in the Cu2O photocatalytic performance. This article provides a novel method and idea to realize the efficient removal of organic dye pollutants in sewage.


Author(s):  
Ali Soltani ◽  
Mehdi Faramarzi ◽  
Seyed Aboutaleb ◽  
Mousavi Parsa

Abstract Industrial effluents are usually one of the major industries polluting the environment and surface water. It is estimated that the worldwide production of dyes is about 70 tons/year. To overcome this problem, innovative processes are suggested for the treatment of industrial effluents containing dyes and heavy metals. The goal of the processes is often to reduce the toxicity of these pollutants in order to meet treatment standards. Recently, great attention has been paid to innovative processes for physical and chemical removal techniques such as adsorption on new adsorbents, biomass adsorption, membrane filtration, irradiation, and electrochemical coagulation. In this study, the application of adsorbents in the adsorption process to remove dye pollutants from industrial effluents has been studied. Factors affecting dye adsorption such as pH, temperature, initial dye concentration, and adsorbent amount are also presented. The obtained results revealed that more than 80% of the dye adsorption on the surface of adsorbents are endothermic processes and more than 95% of the processes obey the pseudo-second-order kinetic model.


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