scholarly journals The Comparison of Photocatalytic Degradation and Decolorization Processes of Dyeing Effluents

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ewa Adamek ◽  
Wojciech Baran ◽  
Justyna Ziemiańska ◽  
Andrzej Sobczak
Keyword(s):  
Photocatalytic Degradation ◽  
Azo Dyes ◽  
Cationic Dyes ◽  
Photocatalytic Process ◽  
Anionic Dyes ◽  
Degradation Of Dyes ◽  
Textile Dyeing ◽  
High Concentrations ◽  
Very High ◽  
Photocatalytic Processes

Treatment of dye effluents resulting from the industrial scale dyeing of cotton, polyacrylic fibres, leather, and flax fabrics by photocatalytic methods was investigated. Photocatalytic processes were initiated by UV-a light (λmax366 nm) and were conducted in the presence of TiO2, TiO2/FeCl3, or FeCl3as photocatalysts. It was found that the photocatalytic process carried out with TiO2and TiO2/FeCl3was the most effective method for decolorization of textile dyeing effluents and degradation of dyes, except for effluents containing very high concentrations of stable azo dyes. During the photocatalytic degradation of anionic dyes, a mixture of TiO2/FeCl3was more effective, while in the case of cationic dyes, more suitable seems to be TiO2alone.

scholarly journals Preparation of TiO2-Poly(3-Chloro-2-Hydroxypropyl Methacrylate) Nanocomposite for Selective Adsorption and Degradation of Dyes

Technologies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 92 ◽  
Author(s):  
M. Hossan ◽  
Bungo Ochiai
Keyword(s):  
Uv Irradiation ◽  
Selective Adsorption ◽  
Industrial Effluents ◽  
Cationic Dyes ◽  
Adsorption Efficiency ◽  
Anionic Dyes ◽  
Propyl Methacrylate ◽  
Accelerated Degradation ◽  
Hydroxypropyl Methacrylate ◽  
Degradation Of Dyes

We report a new nanocomposite TiO2-poly(3-chloro-2-hydroxypropyl methacrylate) (TiO2-PCHPMA) for selective adsorption/degradation of cationic dyes and degradation of anionic dyes. TiO2-PCHPMA was prepared by free radical polymerization of CHPMA in the presence of TiO2 modified with 3-(trimethoxysilyl)propyl methacrylate. TiO2-PCHPMA adsorbed cationic methylene blue (MB), but did not adsorb anionic methyl orange (MO) in their aqueous solutions. The adsorption efficiency for MB reached 99% within 5 min at 28 °C, and adsorbed MB could be recycled in 96% efficiency. The adsorption accelerated degradation of MB under UV irradiation. The degradation of anionic MO proceeded completely with TiO2-PCHPMA under UV irradiation, and the efficiency was not affected by the PCHPMA layer. TiO2-PCHPMA is potentially applicable as a material capable of selective removal and recovery of cationic dyes, and degradation of other dyes from industrial effluents.

scholarly journals Rapid Photocatalytic Degradation of Methylene Blue under High Photon Flux UV Irradiation: Characteristics and Comparison with Routine Low Photon Flux

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Qian Zhang ◽  
Chaolin Li ◽  
Ting Li
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Uv Irradiation ◽  
Irradiation Time ◽  
Photon Flux ◽  
Photocatalytic Process ◽  
Toc Removal ◽  
High Photon Flux ◽  
Degradation Of Dyes ◽  
Photonic Efficiency

This study examined the photocatalytic degradation efficiency under high UV photon flux (intensity normalized by photon energy) irradiation; the incident UV photon flux was einstein   made by a super high-intensity UV apparatus. A comparative study between high photon flux photocatalytic process and routine low photon flux photocatalytic process for methylene blue degradation has been made in aqueous solution. The experimental results showed that under the best conditions of high UV photocatalytic reaction 99% decolorization and 95% TOC removal of 20 mg L−1methylene blue could be achieved in 30 s and 120 s of UV irradiation time, respectively. To the best of our knowledge, photocatalytic decolorization and photocatalytic degradation of dyes in such a short time has not been reported. Aiming at the low photonic efficiency in high photon flux photocatalytic process, we found that reducing the density of excited electron-hole appropriately could improve initial apparent photonic efficiency effectively. The TOC experiments under high UV photon flux showed a faster mineralization rate and a different mineralization process compared to that under low UV photon flux.

scholarly journals Photooxidation Contribution Study on the Decomposition of Azo Dyes in Aqueous Solutions by VUV-Based AOPs

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Chih-Ming Ma ◽  
Gui-Bing Hong ◽  
Hua-Wei Chen ◽  
Nguyen-Thi Hang ◽  
Yung-Shuen Shen
Keyword(s):  
Azo Dyes ◽  
Ph Value ◽  
Reaction Rates ◽  
Degradation Of Dyes ◽  
Degradation Rates ◽  
Effects Of Ph ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
High Concentrations ◽  
Acid Blue

The effects of pH value, VUV intensity, initial dye concentration, initial H2O2concentration, and TiO2loading dose on the degradation of three azo dyes: acid Orange 8, acid Blue 29, and acid Blue 113 were studied to explore and compare the treatment efficiencies among the adopted AOPs. It was found that pH played an important role in the degradation of dyes using VUV irradiation. For VUV/H2O2, VUV/TiO2, and VUV/TiO2/H2O2processes, the decoloration rates of the three azo dyes were more efficient under acidic conditions relative to alkaline conditions. The degradation rates of dyes increased with increasing concentrations of H2O2, but reaction rates were retarded at high concentrations of H2O2because the H2O2compound acted as a scavenger of the hydroxyl radical. In this paper, three azo dyes were decomposed efficiently by VUV irradiation only demonstrating the effectiveness of VUV direct photolysis.

scholarly journals Orange-derived and lemon-derived adsorbents with controlled grain for an efficient elimination of some cationic and anionic dyes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Gemma Pascual ◽  
Josep García-Raurich ◽  
José M. Canal ◽  
Marta Riba-Moliner
Keyword(s):  
Cationic Dyes ◽  
Dyeing Wastewater ◽  
Anionic Dyes ◽  
Efficient Treatment ◽  
Content Type ◽  
Chemically Modified ◽  
Textile Dyeing ◽  
The One ◽  
Acid Blue ◽  
Textile Dyeing Wastewater

Purpose This study aims to demonstrate that orange-derived and lemon-derived systems can be used in continuous processes as efficient adsorbents to the entrapment of some anionic and cationic dyes in the textile dyeing wastewater effluents. Design/methodology/approach Physically and chemically modified orange and lemon mesocarps are used as natural adsorbents for the cationic dyes Basic Blue 3, Basic Yellow 21, Basic Red 18 and Basic Green 4 and the anionic dyes Acid Blue 264, Acid Yellow 49 and Acid Red 337, all commonly used in the textile dyeing industry. Adsorption capacities of the orange-derived and lemon-derived adsorbents on the dyes are studied simulating a batch and continuous industrial processes. Findings Results demonstrate that treated orange mesocarp (orange-derived adsorbent) can adsorb up to 97% of cationic Basic Green 4 in 30 min, whereas the lemon mesocarp (lemon-derived adsorbent) can retain up to 88% within the same time. In the case of anionic, 91% Acid Blue 264 is adsorbed by the orange mesocarp in 15 min, whereas 92% is adsorbed by the lemon homologue within the same time. Originality/value As far as the authors know, physically and chemically modified orange and lemon mesocarps have not been used on the removal of cationic (Basic Blue 3, Basic Yellow 21, Basic Red 18 and Basic Green 4) and anioinic (Acid Blue 264, Acid Yellow 49 and Acid Red 337) dyes of textile dyeing wastewater industry. It is a costless and efficient treatment that supposes, on the one hand, an eco-friendly and feasible process for discolouration of wastewater and, on the other, a valorisation (upcycling) of orange and lemon peels, which are not currently used.

The metachor as a characteristic of the association of electrolytes in aqueous solutions

1984 ◽  
Vol 49 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
Jiří Čeleda ◽  
Stanislav Škramovský
Keyword(s):  
Aqueous Solutions ◽  
Apparent Volume ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
The Difference ◽  
High Concentrations ◽  
Experimental Values ◽  
Suitable Characteristic ◽  
Association Of Ions ◽  
Very High

Based on the earlier paper introducing a concept of the apparent parachor of a solute in the solution, we have eliminated in the present work algebraically the effect which is introduced into this quantity by the additivity of the apparent molal volumes. The difference remaining from the apparent parachor after substracting the contribution corresponding to the apparent volume ( for which the present authors suggest the name metachor) was evaluated from the experimental values of the surface tension of aqueous solutions for a set of 1,1-, 1,2- and 2,1-valent electrolytes. This difference showed to be independent of concentration up to the very high values of the order of units mol dm-3 but it was directly proportional to the number of the free charges (with a proportionality factor 5 ± 1 cm3 mol-1 identical for all studied electrolytes). The metachor can be, for this reason, a suitable characteristic for detection of the association of ions and formation of complexes in the solutions of electrolytes, up to high concentrations where other methods are failing.

scholarly journals Nitrification Process in a Nuclear Wastewater with High Load of Nitrogen, Uranium and Organic Matter under ORP Controlled

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1607
Author(s):  
Mariano Venturini ◽  
Ariana Rossen ◽  
Patricia Silva Paulo
Keyword(s):  
Ammonia Oxidation ◽  
High Load ◽  
Nuclear Fuels ◽  
Monod Model ◽  
Nernst Equation ◽  
Nitrification Process ◽  
Real Wastewater ◽  
High Concentrations ◽  
Wastewater Samples ◽  
Very High

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.

scholarly journals Halogenated Volatile Organic Compounds in Water Samples and Inorganic Elements Levels in Ores for Characterizing a High Anthropogenic Polluted Area in the Northern Latium Region (Italy)

2021 ◽  
Vol 18 (4) ◽  
pp. 1628
Author(s):  
Mario Vincenzo Russo ◽  
Ivan Notardonato ◽  
Alberto Rosada ◽  
Giuseppe Ianiri ◽  
Pasquale Avino
Keyword(s):  
Organic Compounds ◽  
Mean Value ◽  
Greenhouse Crops ◽  
River Waters ◽  
Liquid Liquid Extraction ◽  
Volatile Organic ◽  
High Concentrations ◽  
Very High ◽  
Inorganic Fraction

This paper shows a characterization of the organic and inorganic fraction of river waters (Tiber and Marta) and ores/soil samples collected in the Northern Latium region of Italy for evaluating the anthropogenic/natural source contribution to the environmental pollution of this area. For organic compounds, organochloride volatile compounds in Tiber and Marta rivers were analyzed by two different clean-up methods (i.e., liquid–liquid extraction and static headspace) followed by gas chromatography–electron capture detector (GC-ECD) analysis. The results show very high concentrations of bromoform (up to 1.82 and 3.2 µg L−1 in Tiber and Marta rivers, respectively), due to the presence of greenhouse crops, and of chloroform and tetrachloroethene, due to the presence of handicrafts installations. For the qualitative and quantitative assessment of the inorganic fraction, it is highlighted the use of a nuclear analytical method, instrumental neutron activation analysis, which allows having more information as possible from the sample without performing any chemical-physical pretreatment. The results have evidenced high levels of mercury (mean value 88.6 µg g−1), antimony (77.7 µg g−1), strontium (12,039 µg g−1) and zinc (103 µg g−1), whereas rare earth elements show levels similar to the literature data. Particular consideration is drawn for arsenic (414 µg g−1): the levels found in this paper (ranging between 1 and 5100 µg g−1) explain the high content of such element (as arsenates) in the aquifer, a big issue in this area.

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