scholarly journals Photocatalytic treatment of textile dyehouse effluents with simulated and natural solar light

2013 ◽  
Vol 15 (1) ◽  
pp. 21-28 ◽  

In the present study, the photocatalytic treatment of two synthetic textile dyehouse effluents was investigated. The first synthetic effluent (SE1) is a Remazol Black B aqueous solution, while the second one (SE2) is an aqueous mixture of sixteen dyes and auxiliary chemicals that are usually employed in the textile industry. Various illumination sources were studied, while emphasis was given on the use of simulated and natural solar light. Results indicated that the use of solar irradiation can constitute an advantageous treatment strategy, due to its energy efficient and environmentally friendly operation, for textile dyehouse effluents. Specifically, it was observed that total decolorization and mineralization of SE1 occurred after about 120 min and 300 min, respectively, in the presence of at least 2 g L-1 TiO2, under natural sunlight. On the other hand, total decolorization of SE2 was achieved only after 300 min of photocatalytic treatment, while COD removal practically remained unchanged, at about 20%, regardless the applied operating parameters, due to the presence of other organic and inorganic substances. Furthermore, it was found that process efficiency was significantly affected by the catalyst loading.

2021 ◽  
Vol 9 (2) ◽  
pp. 19-22
Author(s):  
Salihu Yahuza ◽  
Ibrahim Alhaji Sabo ◽  
Hadiza Aliyu Biu

Azo dyes, such as Remazol Black B, are different from conventional dyes in that they establish covalent bonds with textile fibers like cotton. They are widely utilized in the textile industry because of their favorable properties of bright color, water resistance, simple application procedures, and low energy consumption. Their discharge into receiving streams has major environmental consequences, such as reducing photosynthesis in aquatic life due to lower light penetration. The biosorption isotherm data of Remazol Black B dye biosorption by Aspergillus flavus were investigated using two models—pseudo-1st order and pseudo-2nd order—and fitted using non-linear regression. The pseudo-1st order model was found to be the best by statistical analysis using root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian Information Criterion (BIC), and Hannan–Quinn information criterion (HQC). At 250 mg/L, kinetic analysis using the pseudo-1st order model yielded an equilibrium sorption capacity qe of 4.61 mg/g (95 % confidence interval from 4.54 to 4.68) and a pseudo-1st-order rate constant, k1 of 0.15 (95% C.I. from 0.128 to 0.164).


2011 ◽  
Vol 9 (5) ◽  
pp. 867-876 ◽  
Author(s):  
Monika Wawrzkiewicz ◽  
Zbigniew Hubicki

AbstractIn this study, the use of the weakly basic anion exchange resins of phenol-formaldehyde (Amberlyst A 23), polyacrylate (Amberlite IRA 67) and polystyrene (Lewatit MonoPlus MP 62) matrices for removal of the reactive dye Remazol Black B (RBB) from aqueous solution and wastewater were investigated. RBB sorption on the anion exchangers was a time dependent process. Color reduction percentiles of 75.2, 33.9 and 25.1% in wastewater treatment were found after 216 h of phase contact time with Lewatit MonoPlus MP 62, Amberlyst A 23 and Amberlite IRA 67, respectively. Inorganic salts and anionic surfactant action influenced RBB uptake by the anion exchangers. The amounts of dye retained by the anion exchangers increased with a rise in temperature. The maximum sorption capacities calculated from the Langmuir model were 66.4, 282.1 and 796.1 mg g−1 for Amberlite IRA 67, Amberlyst A 23 and Lewatit MonoPlus MP 62, respectively. Regeneration of phenol-formaldehyde and polystyrene resins were possible using 1 M NaOH, 2 M KSCN, 1M KSCN in 40–60% methanol as well as 1 M NaOH in 60% methanol.


2012 ◽  
Vol 455-456 ◽  
pp. 1339-1344 ◽  
Author(s):  
Zhe Qi Li ◽  
Jing Yu Liu

Photodegradation ofp-nitrophenol catalyzed by ZnO/MWCNTs composite in water was investigated. The effects of pH, irradiation time, catalyst loading, initial substrate concentration and MWCNTs content on the degradation were investigated. Experiment results revealed that the optimal conditions were ap-nitrophenol concentration of 60.0 mg/L at pH 5.0 with catalyst loading of 10.0 g/L under solar irradiation for the illumination of 180 min. The highest efficiency on photodegradation ofp-nitrophenol can be achieved with an optimal MWCNTs/ZnO mass ratio of 0.16%. Possible decomposing mechanisms were also discussed. The repeatability of photocatalytic activity was tested. The photocatalyst was used ten cycles with degradation efficiency still higher than 95%. The results of the study showed the feasible and potential use of ZnO/MWCNTs composite in degradation of toxic organic pollutants.


Author(s):  
Basma Ghazal ◽  
Saad Makhseed

Novel composites of zinc oxide (ZnO) and copper phthalocyanines (CuTriPc and CuPc) were synthesized as efficient natural solar light photocatalysts for the photodegradation of organic wastewater pollutants. Spectroscopic and analytical measurements confirmed that both bulky triazolo copper phthalocyanine (CuTriPc) and unsubstituted planer (CuPc) were successfully coupled with ZnOnanoparticles. The synthesized nanocomposites were investigated as natural solar radiation photocatalysts toward the photodegradation of methylene blue (MB) analogue dye. The prepared CuTriPc/ZnO nanocomposite was proven to be an efficient solar light photocatalyst compared to pure ZnO and the unsubstituted CuPc/ZnO.


Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1157 ◽  
Author(s):  
Erika Pia Vergura ◽  
Sara Garcia-Ballestreros ◽  
Rosa Francisca Vercher ◽  
Lucas Santos-Juanes ◽  
Alessandra Bianco Prevot ◽  
...  

In the present work, the photo-Fenton degradation of pentachlorophenol (PCP, 1 mg/L) has been studied under simulated and natural solar irradiation; moreover, the effect on the process efficiency of urban waste-derived soluble bio-based substances (SBO), structurally comparable to humic acids, has been investigated. Experiments showed a crucial role of PCP photolysis, present in the solar pilot plant and hindered by the Pyrex® filter present in the solar simulator. Indeed, the SBO screen negatively affects PCP degradation when working under natural solar light, where the photolysis of PCP is relevant. In contrast, in the absence of PCP photolysis, a significant improvement of the photo-Fenton process was observed when added to SBO. Furthermore, SBO were able to extend the application of the photo-Fenton process at circumneutral pH values, due to their ability to complex iron, avoiding its precipitation as oxides or hydroxides. This positive effect has been observed at higher concentration of Fe(II) (4 mg/L), whereas at 1 mg/L, the degradation rates of PCP were comparable in the presence and absence of SBO.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Pham Dinh Du ◽  
Huynh Thi Minh Thanh ◽  
Thuy Chau To ◽  
Ho Sy Thang ◽  
Mai Xuan Tinh ◽  
...  

In the present paper, the synthesis of metal-organic framework MIL-101 and its application in the photocatalytic degradation of Remazol Black B (RBB) dye have been demonstrated. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption isotherms at 77 K. It was found that MIL-101 synthesized under optimal conditions exhibited high crystallinity and specific surface area (3360 m2·g-1). The obtained MIL-101 possessed high stability in water for 14 days and several solvents (benzene, ethanol, and water at boiling temperature). Its catalytic activities were evaluated by measuring the degradation of RBB in an aqueous solution under UV radiation. The findings show that MIL-101 was a heterogeneous photocatalyst in the degradation reaction of RBB. The mechanism of photocatalysis was considered to be achieved by the electron transfer from photoexcited organic ligands to metallic clusters in MIL-101. The kinetics of photocatalytic degradation reaction were analyzed by using the initial rate method and Langmuir-Hinshelwood model. The MIL-101 photocatalyst exhibited excellent catalytic recyclability and stability and can be a potential catalyst for the treatment of organic pollutants in aqueous solutions.


2018 ◽  
Vol 13 ◽  
pp. 117739011876336 ◽  
Author(s):  
Eman Alzahrani

Fast Green (FCF) dye is commonly used in both cytology and histology applications. Previous studies have found that it can cause mutagenic and tumorigenic effects in experimental human and animal populations. It can also be a source of skin, eye, respiratory, and digestive irritation. The purpose of this study was to examine the use of thin film membranes to degrade FCF. A thin film membrane of chitosan (CS) was fabricated and subsequently filled with zinc oxide nanoparticles (ZnO) or ZnO/CuO-heterostructured nanocomposites. The CS membrane was used as a matrix, and the nanomaterials were used as photocatalysts. The prepared membranes were characterised by four analytical techniques: atomic force microscopy, scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray analyses. The photocatalytic activity of the fabricated membranes was evaluated by performing experiments in which aqueous solutions of FCF dye that contained the fabricated membrane were irradiated with solar light or UV light. The photodegradation percentage was spectrophotometrically determined by monitoring the maximum wavelengths (λmax) of FCF at 623 nm for different irradiation times. The decolourisation percentages of the dye under solar light were 57.90% and 60.23% using the CS-ZnO and CS-ZnO/CuO membranes, respectively. When UV light irradiation was employed as the source of irradiation, the photodegradation percentages of FCF were 71.45% and 91.21% using the CS-ZnO and CS-ZnO/CuO membranes, respectively. These results indicated that the best photocatalytic system for the degradation of FCF dye was CS-ZnO/CuO membrane in combination with UV light irradiation. The study also found that it was easy to separate the prepared membranes after the reaction without the need for a centrifuge or magnet. The results demonstrate the potential for CS-ZnO and CS-ZnO/CuO membranes for use as effective sorbents during the process of photodegradation of harmful dyes within waste water recycling practices.


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