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1 – 10 of 65Wei Zhang, Mengdi Zhang, Zhijie Huangfu, Jiming Yao and Yuan Xie
This study aims to explore suitable anode materials used in the electrochemical system for indigo dyeing wastewater, to achieve optimal treatment performances.
Abstract
Purpose
This study aims to explore suitable anode materials used in the electrochemical system for indigo dyeing wastewater, to achieve optimal treatment performances.
Design/methodology/approach
The single factor experiment was used to explore the optimum process parameters for electrochemical decolorization of indigo dyeing wastewater by changing the applied voltage, electrolysis time and electrolyte concentration. At the voltage of 9 V, the morphology of flocs with different electrolytic times was observed and the effect of electrolyte concentration on decolorization rate in two electrolyte systems was also investigated. Further analysis of chemical oxygen demand (COD) removal rate, anode weight loss and sediment quantity after electrochemical treatment of indigo dyeing wastewater were carried out.
Findings
Comprehensive considering the decolorization degree and COD removal rate of the wastewater, the aluminum electrode showed the best treatment effect among several common anode materials. With aluminum electrode as an anode, under conditions of applied voltage of 9 V, electrolysis time of 40 min and sodium sulfate concentration of 6 g/L, the decolorization percentage obtained was of 94.59% and the COD removal rate reached at 84.53%.
Research limitations/implications
In the electrochemical treatment of indigo dyeing wastewater, the aluminum electrode was found as an ideal anode material, which provided a reference for the choice of anodes. The electrodes used in this study were homogenous material and the composite material anode needed to be further researched.
Practical implications
It provided an effective and practical anode material choice for electrochemical degradation of indigo dyeing wastewater.
Originality/value
Combined with the influence of applied voltage, electrolysis time and electrolyte concentration and anode materials on decolorization degree and COD removal rate of indigo dyeing wastewater, providing a better electrochemical treatment system for dyehouse effluent.
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Wei Zhang, Weiwei Lv, Xiaoyan Li and Jiming Yao
In this study, the oxidative degradation performance of indigo wastewater based on electrochemical systems was explored. The decolourization degrees, removal rate of chemical…
Abstract
Purpose
In this study, the oxidative degradation performance of indigo wastewater based on electrochemical systems was explored. The decolourization degrees, removal rate of chemical oxygen demand and biochemical oxygen demand of the indigo wastewater after degradation were evaluated and optimized treatment conditions being obtained.
Design/methodology/approach
The single factor method was first used to select the electrolyte system and electrode materials. Then the response surface analysis based on Box–Behnken Design was chosen to determine the influence of four independent variables such as FeCl3 concentration, NaCl concentration, decolourization time and voltage on the degradation efficiency.
Findings
On the basis of single factor experiment, the electrode material of stainless steel was selected in the double cell, and the indigo wastewater was electrolyzed with FeCl3 and NaCl electrolytes. The process conditions of electrochemical degradation of indigo wastewater were optimized by response surface analysis: the concentration of FeCl3 and NaCl was of 16 and 9 g/L, respectively, with a decolourization time of 50 min, voltage of 10 V and decolourization percentage of 98.94. The maximum removal rate of chemical oxygen demand reached 75.46 per cent. The highest ratio of B/C was 3.77, which was considered to be more biodegradable.
Research limitations/implications
Dyeing wastewater is bringing out more and more pollution problems to the environment. However, there are some shortcomings in traditional technologies such as adsorption and filtration. As a kind of efficient and clean water treatment technology, electrochemical oxidation has been applied to the treatments of various types of wastewater. The decolourization and degradation of indigo wastewater is taken as an example to provide reference for the treatment of wastewater in actual plants.
Practical implications
The developed method provided a simple and practical solution for efficiently degrading indigo wastewater.
Originality/value
The method for the electrochemical oxidation technology was novel and could find numerous applications in the degradation of printing and dyeing wastewater.
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Qin Xiaoxuan, Hui’e Liang, Xuzhong Su and Xinjin Liu
As a natural fiber, yakwool has attracted much attention in textile processing due to its excellent properties and wearabilities. However, the main colors of yakwool are black and…
Abstract
Purpose
As a natural fiber, yakwool has attracted much attention in textile processing due to its excellent properties and wearabilities. However, the main colors of yakwool are black and brown. Therefore, for extending the application scopes of the fiber, the decolorization of the yakwool fiber is usually needed, especially for the black fiber. The paper aims to discuss this issue.
Design/methodology/approach
In the paper, the properties of the yakwool fiber were tested first, especially the melanin granules in the fiber. Then, the decolorization of the yakwool fiber was studied using the oxidation–reduction decolorization method, and corresponding optimal process of the decolorization was given. Then, the properties of the decolorized yakwool fiber were tested and compared with those of the original fiber.
Findings
It is shown that, after decolorization, the physical and mechanical properties of the fiber were deteriorated, especially in terms of the strength and elongation. Therefore, the fiber became shorter and thinner, and the scales were damaged. When compared with the yarn spun from the original yakwool fiber, it was observed that the properties of the yarn spun from the decolorized yakwool fiber deteriorated because of the deterioration in the properties of the original fiber.
Originality/value
In the paper, for extending the application scopes of the yakwool fiber, the decolorization of the yakwool fiber was studied.
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In this study, the removal of a series of acid dyes by hybrid polymer adsorbent was investigated. Textile industry wastewater is mainly consisted of suspended solid particles and…
Abstract
Purpose
In this study, the removal of a series of acid dyes by hybrid polymer adsorbent was investigated. Textile industry wastewater is mainly consisted of suspended solid particles and organic compounds with complex and nondecomposable structures. Treatment of such wastewaters has received much attention by researchers because of high water consumption and the presence of various chemical compounds, especially dyes. The use of polymers has recently attracted much attention for the treatment of textile wastewaters. According to the literature, hybrid polymers are highly capable of adsorbing dyes. In this research work, polyacrylamide/iron sulfate (PAM-FeSO4) hybrid polymer was successfully synthesized through solution polymerization of acrylamide with ammonium persulfate and sodium thiosulfate and gradual addition of iron sulfate. The hybrid polymeric adsorbent was then used for removing acidic dyes with different chemical structures.
Design/methodology/approach
The effects of various experimental conditions and parameters, such as initial concentrations of dye and adsorbent, on the adsorption capacity of the adsorbent were investigated. The dye concentration was measured by an UV–vis spectrophotometer. The adsorption equilibrium was studied by plotting adsorption isotherms. The experimental data was fitted to Langmuir and Freundlich isotherms.
Findings
The adsorption experiments indicated that the PAM-FeSO4 hybrid polymer has a high adsorption capacity (117.64 mg g−1 for the Orange ІІ and 80.64 mg g−1 for the Sunset Yellow [SY]) when 80 mg of adsorbent was immersed in the dye solution (1 g L−1) with a pH of 11 at 25°C. The analysis of the equilibrium isotherms using the Langmuir and Freundlich isotherms indicated that the Langmuir model fit well to the experimental data.
Originality/value
To the best of the authors’ knowledge, this study is original. The removal of acid dyes such as Sunset Yellow and Methyl Orange using PAM-FeSO4 hybrid polymer as flocculant was done for the first time.
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Shu-Hao Deng, Xi Yang, Mao Wang and Jiao Wang
– The purpose of this paper is to improve anti-corrosion, self-cleaning, hydrophily and sterilization properties of aluminum (Al) alloy.
Abstract
Purpose
The purpose of this paper is to improve anti-corrosion, self-cleaning, hydrophily and sterilization properties of aluminum (Al) alloy.
Design/methodology/approach
A multifunctional coating for medical external application on Al alloy had been prepared by anodic oxidation, electrolytic coloring silver (Ag) and sealed in boiling water with nano-sized titanium dioxide (TiO2) particles. The multifunctional coating was characterized by X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy. Other properties such as corrosion-resistance, wipe-resistance, hydrophilicity, photochemical decomposition and bactericidal antiseptic effect were also investigated.
Findings
The results demonstrate that a golden film with multi-function had been obtained for medical external application. The main phase of coating is amorphous Al2O3, and nano-sized silver particle is electrodeposited in bottom of film hole, while nano-sized TiO2 is sealed on the external surface of coating. The properties of film, such as anti-corrosion, self-cleaning, hydrophily, sterilization are better than those of Al alloy substrate.
Originality/value
Considering about this usage for medical external application, a multifunctional coating which has the properties such as decoration, anti-corrosion, sterilize and self-cleaning has been first prepared on Al alloy surface in the study. This coating would meet the requirements of medical external using and provide theoretical and practical foundation about Al alloy for medical use.
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Shahin Ahmadi, Bahaaddin Mahmoodi, Mohammad Kazemini and Niyaz Mohammad Mahmoodi
Environmental issues and lack of drinking water have forced researchers to find some alternatives to wastewater treatment. Because dyes are used in a variety of industrial…
Abstract
Purpose
Environmental issues and lack of drinking water have forced researchers to find some alternatives to wastewater treatment. Because dyes are used in a variety of industrial applications such as textile and pharmaceutical, wastewater of these factories leads to several environmental problems. Using catalysis under ultraviolet-irradiation (photocatalysis) is one of the cases that is used in wastewater treatment. The purpose of this work is the photocatalytic degradation of dye (Reactive Red 198) and pharmaceutical (tetracycline) using MIL-53(Fe) and MIL-100(Fe).
Design/methodology/approach
In this work, Reactive Red 198 (RR198), an anionic dye and tetracycline as a pharmaceutical are tested with two catalysts, MIL-53(Fe) and MIL-100(Fe). Catalyst synthesis method and characterization were discussed by X-ray diffraction, scanning electron microscopy and Fourier Transform Infrared analyses, and their results are described in detail.
Findings
Dye concentration varies among 15, 20, 30 and 40 mg/L for MIL-100(Fe) for which the removal percent is 97%, 94%, 89% and 58% and for MIL-53(Fe), dye concentration increases from 20 to 40, 60 and 80 mg/L, the removal percent of which is 98%, 88%, 75% and 50%. Pharmaceutical degradation by MIL-53(Fe) and MIL-100(Fe) was 75% and 80%, respectively.
Originality/value
Photocatalytic degradation of RR198 and tetracycline using MIL-53(Fe) and MIL-100(Fe) was not studied in detail.
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Amal A. Aly, Safia A. Mahmoud and Morsy Ahmed El-Apasery
This paper aims to decolorize the effluents of textile Reactive Orange 5 and Reactive Red 195 dyes by using cationized sugarcane bagasse.
Abstract
Purpose
This paper aims to decolorize the effluents of textile Reactive Orange 5 and Reactive Red 195 dyes by using cationized sugarcane bagasse.
Design/methodology/approach
Cationized sugarcane bagasse was prepared and used as an adsorbent for both reactive and hydrolyzed reactive dyes. Characterization of the sugarcane bagasse structure resulted by cationization was monitored using Fourier transform–infrared, while morphologically was detected using scanning electron microscopy and X-ray powder diffraction.
Findings
The maximum adsorption capacities are 805, 1,664, 1,772 and 1,596 mg/g for Hydrolyzed Red 195, Hydrolyzed Orange 5, Reactive Red 195 and Reactive Orange 5 dyes, respectively.
Research limitations/implications
Factors affecting the percentage of dye removal were optimized on different parameters such as adsorbent dose and treatment time. The data were discussed using the Langmuir and Freundlich Models of adsorption.
Practical implications
The reuse of hydrolyzed reactive dyebaths gives reasonably good fastness properties on nylon fabrics.
Social implications
The study has enabled the production of an eco-friendly and less expensive method of reactive dye effluent decolorization.
Originality/value
The study provides a potentially simple approach to decolorize dye effluents of Reactive Orange 5, Red 195 dyes and also the reuse of hydrolyzed reactive dyebaths for dyeing nylon.
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Alireza Khataee, Leila Moradkhannejhad, Vahid Heydari, Behrouz Vahid and Sang Woo Joo
This paper aims to study the Improvements in self-cleaning property of the white acrylic water-based paint by addition of different percentages of three commercially available…
Abstract
Purpose
This paper aims to study the Improvements in self-cleaning property of the white acrylic water-based paint by addition of different percentages of three commercially available titanium dioxide (TiO2) nanoparticles as additives. Then, due to the risk of destruction of polymeric materials in the presence of nanoparticles, degradation of dry paint film samples was investigated for 15 days using two important chalking and yellowing factors. Finally, the TiO2-modified paint sample with the best performance and optimum percentage of TiO2 nanoparticles that produced desired self-cleaning and dry film properties was introduced.
Design/methodology/approach
Self-cleaning and dry film properties of white acrylic water-based paint were investigated by addition of three various types of commercial available TiO2 nanoparticles (SSP-25, STA-100 and KA-100). X-ray diffraction, transmission electron microscopy and Brunauer–Emmett–Teller were used for characterization of TiO2 samples. Colorimetric tests in decolourization of C.I. Basic Red 46 (BR46) were used for determination of self-cleaning properties of TiO2-modified paints in comparison with unmodified paint sample. Also, paints defects such as chalking and yellowing were tested along two weeks.
Findings
The results indicated that, in all types of TiO2 nanoparticles, by increasing the amount of TiO2 in modified paint, self-cleaning property of the samples was enhanced. The paint containing SSP-25 indicated better self-cleaning properties than others due to its larger surface area. However, its usage above 3.5 weight per cent caused yellowing and chalking defects in dried paint film.
Practical implications
In this research, TiO2-modified paint sample with the best performance in both self-cleaning and mechanical properties was selected among the nine sets of prepared paint samples. All the materials used in this research such as acrylic resin and three types of TiO2 nanoparticles are of industrial grade. Therefore, the introduced TiO2-modified paint sample has the potential for the commercial production as a building exterior paint.
Originality/value
In the present study, an attempt at introducing a self-cleaning paint sample with acceptable mechanical properties using three types of commercially available TiO2 nanoparticles as additives and industrial grade of acrylic resin which is the most commonly used water-based resin in building paints, as binder. As far as it was searched in the literatures, the parallel study of the self-cleaning and mechanical properties of paints has not been reported as noteworthy. Self-cleaning property of the acrylic water-based paint samples was investigated by adding three types of the commercially available TiO2 nanoparticles. Also considering the possible detrimental effects of TiO2 nanoparticles on polymeric materials and consequently on physical properties of the paint, chalking and yellowing factors in dried paint samples were evaluated.
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Maja Radetic, Darinka Radojevic, Vesna Ilic, Darka Mihailovic and Petar Jovancic
The purpose of this paper is to investigate the possible application of recycled wool‐based nonwoven material (RWNM) for removal of different dyes that are used in textile dye…
Abstract
Purpose
The purpose of this paper is to investigate the possible application of recycled wool‐based nonwoven material (RWNM) for removal of different dyes that are used in textile dye houses.
Design/methodology/approach
The sorption kinetics, the influence of initial dye concentration, pH and temperature are analyzed. Basic, reactive, direct and metal complex dyes are studied.
Findings
The sorption properties are highly influenced by the type of the dye owing to differences in their chemical structure and thus, the mechanism of binding to wool. Modification of material with chitosan and hydrogen peroxide improves the sorption capacities and sorption rates but no general trend can be established. Consequently, the sorption behaviour is analyzed separately for each type of the dye.
Originality/value
The results indicate that RWNM can be used as an efficient, low‐cost sorbent for decolorisation of effluents.
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N.M. Abdel Monem, N.M. Al‐Mansi and M.S. El‐Nawasra
The removal of Ismative SHR blue (reactive dye) using a very cheap cement factory waste called by‐pass kiln dust has been investigated in batch mode. The effects of initial dye…
Abstract
The removal of Ismative SHR blue (reactive dye) using a very cheap cement factory waste called by‐pass kiln dust has been investigated in batch mode. The effects of initial dye solution concentration, particle size, agitation rate, amount of by‐pass kiln dust, and dye solution temperature were studied. A 95.5 per cent removal was achieved. Some pretreatment of by‐pass kiln dust, such as washing by distilled water or rinsing with HCL solution, has been done. By using the washed by‐pass kiln dust the values of total dissolved solids, alkalinity, and efficiency of colour removal were reduced. A very rapid irreversible chemical reaction may occur in addition to the adsorption process. Ferric chloride was used as a coagulant after settling to complete the separation of the dust from the clear solution. A removal of 96 per cent from the initial colour of the industrial coloured wastewater was achieved.
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