scholarly journals Selective oxidation and direct decolorization of cationic dyes by persulfate without activation

2021 ◽  
Author(s):  
Bing Yang ◽  
Qiuping Luo ◽  
Qinman Li ◽  
Yuan Meng ◽  
Li Lingli ◽  
...  
Keyword(s):  
Selective Oxidation ◽  
Organic Dyes ◽  
Direct Electron Transfer ◽  
Cationic Dyes ◽  
Dye Wastewater ◽  
Oxidation Treatment ◽  
Radical Oxidation ◽  
Decolorization Rate ◽  
Plausible Mechanism ◽  
Ph Conditions

Abstract The aim of this work was to investigate the selective oxidation and direct decolorization of selected organic dyes (Methylene Blue (MB), Rhodamine B (RhB) and Orange II (OrgII)) by persulfate (PDS) without activation. Results show that the decolorization rate of MB was up to 58.0% within 10 minutes, while those of RhB and OrgII were only about 29.6% and 3.0% after 80 minutes, respectively. In comparison with the negligible impacts of pH from 2.0 to 9.0 on MB and OrgII decolorization, RhB decolorization rate obviously varied with the pH changes, and acid pH condition was beneficial for RhB decolorization. Quenching tests implied that the decolorization of dyes by PDS without activation was a nonradical oxidation processes rather than sulfate radical oxidation. A plausible mechanism is that the decolorization process is attributed to the charged states of the dyes at different pH conditions, and thus direct electron transfer from dyes to PDS may occur, which is responsible for the bleaching of dyes. This study points out the potential bleaching capability of PDS without activation on cationic dyes, which may have important implications for selective oxidation treatment of dye wastewater.

scholarly journals Enhancing the activation of persulfate using nitrogen-doped carbon materials in the electric field for the effective removal of p-nitrophenol

RSC Advances ◽  
2021 ◽  
Vol 11 (60) ◽  
pp. 38003-38015
Author(s):  
Mengdi Tang ◽  
Yonggang Zhang
Keyword(s):  
Electron Transfer ◽  
Free Radical ◽  
Electric Field ◽  
Carbon Materials ◽  
Direct Electron Transfer ◽  
Free Radical Oxidation ◽  
Radical Oxidation ◽  
Nitrogen Doped ◽  
Effective Removal ◽  
Nitrogen Doped Carbon

In the process of electro-activation of PDS by carbon cathode, PNP was removed from water mainly through SO4˙− produced by cathode, ˙OH and 1O2 produced indirectly, direct electron transfer and non-free radical oxidation of anode.

Nanomaterial Surface Modifications for Enhancement of the Pollutant Adsorption From Wastewater

2019 ◽  
pp. 143-170 ◽  
Author(s):  
Hamidreza Sadegh ◽  
Gomaa A. M. Ali ◽  
Hamid Jafari Nia ◽  
Zahra Mahmoodi
Keyword(s):  
Membrane Filtration ◽  
Organic Dyes ◽  
Low Cost ◽  
Aquatic Organisms ◽  
Chemical Degradation ◽  
Photochemical Degradation ◽  
Dye Wastewater ◽  
Biological Degradation ◽  
Operation Costs ◽  
Global Concern

With the development of dyeing, textile, leather, paper, and other chemical industries, an increasing amount of dye wastewater containing refractory organic dyes is discharged. Undoubtedly, much high content dye wastewater will lead to serious environmental issues such as color pollution, light penetration interference, and virulence to aquatic organisms, even endanger human health. Therefore, it is an imminent problem and has become a global concern to degrade dye wastewater efficiently. So far, many techniques have been used to degrade dyeing wastewater, such as chemical degradation, biological degradation, photochemical degradation, coagulation, membrane filtration, and combined methods. These methods have certain impacts on the degradation of dye wastewater, but usually with slow degradation rate, complex and high operation costs, as well as easily causing secondary pollution. The adsorption process is a simple, effective, and low-cost way to remove dyes.

scholarly journals Preparation Method of Iron Oxyhydroxide Nanosheets for Treating Organic Dyes

2022 ◽  
Vol 2152 (1) ◽  
pp. 012043
Author(s):  
Weijie Lian ◽  
Lan Ma ◽  
Bo Chen ◽  
Yuxin Zhai ◽  
Yibo Wen
Keyword(s):  
Congo Red ◽  
Preparation Method ◽  
Organic Dyes ◽  
Molar Ratio ◽  
Dye Wastewater ◽  
Iron Oxyhydroxide ◽  
Adsorption Efficiency ◽  
Strong Adsorption ◽  
Efficiency Increase ◽  
Low Dosage

Abstract Considering the promoted purification requirement for industry sewage, the discharge of azo dye wastewater will have a serious impact on the environment, iron oxyhydroxide nanosheets were designed and prepared, and the purification effects and application conditions were investigated in this work. We have used its structural advantages to perform adsorption tests on Congo red (CR). It found that it has very excellent properties. It has strong adsorption capacity for Congo red under the condition of low dosage and no adjustment of PH. By employing iron oxyhydroxide nanosheets with optimized molar ratio of reducing agent to Fe, it was found that the adsorption efficiency increase in the removal percentage for CR from industry sewage could be achieved at the large specific surface area and pore volume of B-Fe Nanosheets.

scholarly journals Ce-doped UiO-67 nanocrystals with improved adsorption property for removal of organic dyes

RSC Advances ◽  
2019 ◽  
Vol 9 (47) ◽  
pp. 27674-27683 ◽  
Author(s):  
Xue Dong ◽  
Yongcen Lin ◽  
Yuqin Ma ◽  
Lang Zhao
Keyword(s):  
Adsorption Capacity ◽  
Hydrothermal Method ◽  
Negative Charge ◽  
Organic Dyes ◽  
Adsorption Property ◽  
Cationic Dyes ◽  
High Adsorption ◽  
One Step ◽  
High Adsorption Capacity

The Ce-doped UiO-67 nanocrystals were successfully synthesized via a one-step hydrothermal method. Ce doping increases the negative charge on the surface of the material, thus the adsorbent exhibits high adsorption capacity to cationic dyes.

Rational synthesis of isomorphic rare earth metal-organic framework materials for simultaneous adsorption and photocatalytic degradation of organic dyes in water

CrystEngComm ◽  
2021 ◽  
Author(s):  
Meng-Ting Hang ◽  
Yi Cheng ◽  
Yi-Tong Wang ◽  
Huan Li ◽  
Meng-Qi Zheng ◽  
...  
Keyword(s):  
Active Sites ◽  
Organic Dyes ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Earth Metal ◽  
Dye Wastewater ◽  
Porous Structures ◽  
Framework Materials ◽  
Metal Organic ◽  
Ordered Porous

In recent years, the treatment of dye wastewater has attracted widespread attention. Metal-organic frameworks (MOFs) adopt ordered porous structures and abundant active sites, which endorses them promising photocatalysts for the...

Encapsulation of tungstophosphoric acid into harmless MIL-101(Fe) for effectively removing cationic dye from aqueous solution

RSC Advances ◽  
2016 ◽  
Vol 6 (85) ◽  
pp. 81622-81630 ◽  
Author(s):  
Ting-Ting Zhu ◽  
Zhi-Ming Zhang ◽  
Wei-Lin Chen ◽  
Zhu-Jun Liu ◽  
En-Bo Wang
Keyword(s):  
Aqueous Solution ◽  
Composite Material ◽  
Organic Dyes ◽  
Tungstophosphoric Acid ◽  
Cationic Dyes ◽  
Cationic Dye ◽  
Adsorption Performance

H3PW12O40 was incorporated into cages of harmless MIL-101(Fe). The composite material exhibited excellent adsorption performance for the cationic dyes MB and RhB, can be utilized in the selective capture and separation of organic dyes in water and is reusable and stable.

Treatment of Cationic Dye Wastewater with Hybrid Sorbent Generated by Anionic Dye Wastewater Hybridization with Calcium Fluoride

2013 ◽  
Vol 652-654 ◽  
pp. 1571-1579
Author(s):  
Dan Hua Zhao ◽  
Xiu Lian Zhang ◽  
Wei Yin ◽  
Xiao Jun Liu
Keyword(s):  
Ionic Strength ◽  
Calcium Fluoride ◽  
Low Cost ◽  
Methyl Violet ◽  
Cationic Dyes ◽  
Maximum Adsorption Capacity ◽  
Cationic Dye ◽  
Dye Wastewater ◽  
Anionic Dye ◽  
Hybrid Sorbent

CaF2/AG25 (CFA) hybrid sorbent formed by hybrid reaction with activated calcium fluoride of low cost and anionic dye wastewater-Acid Green 25 (AG25) was used for the treatment of cationic dye wastewater. The adsorption of two cationic dyes methyl violet (MV) and Neutral Red (NR) from aqueous solutions was examined using a batch sorption technique. The effects of time, pH, ionic strength and temperature on the adsorption were also examined. It exhibited a faster adsorption to cationic dyes and hardly affected in pH over 3.5, ionic strength low 0.04 mol/L and temperature between 20 oC and 60 oC. The adsorption behavior of the NR and MV on CFA is in good agreement with the Langmiur isotherms model with the correlation coefficients of R 0.9948 for NR and 0.9992 for MV and the maximum adsorption capacity of NR (39.22 mg/g) and MV (48.78 mg/g). Finally, this sorbent was used in treatment of two practical cationic dye wastewaters with satisfactory results.

Surface-functionalized silica gel adsorbents for efficient remediation of cationic dyes

2014 ◽  
Vol 86 (7) ◽  
pp. 1177-1188 ◽  
Author(s):  
Aleeza Farrukh ◽  
Attia Akram ◽  
Abdul Ghaffar ◽  
Eylül Tuncel ◽  
Zehra Oluz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silica Gel ◽  
Photoelectron Spectroscopy ◽  
Organic Dyes ◽  
Water Soluble ◽  
Cationic Dyes ◽  
Functionalized Silica ◽  
Design And Synthesis ◽  
Effective Removal ◽  
Adsorption Desorption

AbstractThe toxic and non-biodegradable nature of organic dyes necessitates the design and synthesis of novel adsorbents for their effective removal from the environment. This study reports an effective remediation behavior of surface-functionalized silica gel against water-soluble cationic dyes (up to 98 % removal). Thiol groups were functionalized at the surface of silica gel (SiO2–SH). The surface-tethered –SH groups were further oxidized to sulfonic acid groups to generate the negatively charged moieties at the surface of silica gel (SiO2–SO3 H). The morphology of the developed adsorbents and the surface modifications were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Uptake study of three cationic dyes, namely, rhodamine B (Rh B), rhodamine 6G (Rh 6G), and crystal violet (CV) with SiO2–SH and SiO2–SO3 H adsorbents was performed by varying the adsorbent amount, contact time, pH of solution, and temperature. The presence of negatively charged species at the surface of SiO2–SO3 H results in an increased electrostatic interaction with the cationic dyes, which leads to better remediation characteristics for SiO2–SO3 H as compared to SiO2–SH. The reusability of the developed adsorbents was also assessed by investigating adsorption/desorption of dyes. The simple fabrication process provides a facile avenue to the adsorbents with efficient remediation towards cationic dyes.

Preparation and Application of CA/BaSO4 -CR Composite Gel Ball in Cationic Dye Wastewater Treatment

2014 ◽  
Vol 955-959 ◽  
pp. 38-46
Author(s):  
Da Mei Yu ◽  
Yun Lin ◽  
Yi Min Zhang ◽  
Wen Juan Zhou ◽  
Dan Hua Zhao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Calcium Alginate ◽  
Cationic Dyes ◽  
Potential Candidate ◽  
Cationic Dye ◽  
Dye Wastewater ◽  
Adsorption Selectivity ◽  
Adsorption Performance ◽  
Treatment Processes ◽  
Composite Gel

A new hybrid adsorbent of calcium-alginate encapsulated BaSO4-CR (CABSC) has been prepared. The adsorption selectivity and mechanism were studied by investigating the adsorption performance of two anionic and two cationic dyes. The adsorption of two cationic dyes (EV and MB) from aqueous solutions was examined using a batch sorption technique. The effects of time, pH, temperature and ionic strength on the adsorption were examined. Besides, this material was applied in the treatment of two practical cationic dye wastewaters. Our study shows that the sorbent could be a potential candidate for utilization in dye wastewater treatment processes.

scholarly journals Selective Oxidation of Transient Organic Radicals in the Presence of Gold Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 727
Author(s):  
Viacheslav Shcherbakov ◽  
Sergey A. Denisov ◽  
Mehran Mostafavi
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Selective Oxidation ◽  
Room Temperature ◽  
Catalytic Effect ◽  
Organic Dyes ◽  
Organic Radicals ◽  
Species Concentration ◽  
Reactive Oxygen Species Concentration

The ability of gold nanoparticles (AuNPs) to catalyze reactions involving radicals is poorly studied. However, AuNPs are used in applications where chemical reactions involving transient radicals occur. Herein, we investigate AuNPs’ catalytic effect on 2-propanol oxidation and acetanilide hydroxylation in aqueous solutions under ionizing radiation at room temperature. In both cases, the presence of AuNPs led to selective oxidation of organic radicals, significantly changing the products’ composition and ratio. Based on these observations, we stress how AuNPs’ catalytic activity can affect the correctness of reactive oxygen species concentration determination utilizing organic dyes. We also provide a discussion on the role of AuNPs’ catalytic activity in the radiosensitization effect actively studied for radiotherapy.

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