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Article
Publication date: 2 August 2021

Wei 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.

Details

Pigment & Resin Technology, vol. 51 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 13 November 2020

Zhijie Huangfu, Wei Zhang, Shang Hao, Mengdi Zhang and Jiming Yao

This study aims to evaluate the efficiency of metal electrode and electrolytes on the electroflocculation of indigo wastewater, produced by printing and dyeing factory, and to…

Abstract

Purpose

This study aims to evaluate the efficiency of metal electrode and electrolytes on the electroflocculation of indigo wastewater, produced by printing and dyeing factory, and to optimize the treatment system.

Design/methodology/approach

For effective purging, various types of metal electrodes (graphite, pure aluminum and stainless steel) and supporting electrolytes (sodium chloride and sodium sulfate) were selected for electroflocculation experiments. The decolorization rate and chemical oxygen demand (COD) removal rate were characterized.

Findings

The treatment effects of stainless steel and aluminum were similar, but the dissolution loss of aluminum and the production of flocs greatly limit its application. Electrolytes gave obvious effects to these systems. Sodium sulfate was better than sodium chloride, the decolorization rate was increased by 3.31%, the removal rate of COD in the solution was increased by 28.65% and the weight of flocculation precipitation was reduced by 0.214 g.

Research limitations/implications

The electrochemical treatment system was constructed to compare and analyze the influence of experimental parameters and to provide a reference for the actual treatment of indigo wastewater.

Practical implications

Electrochemical flocculation can remove the insoluble indigo solids and it plays a key role in wastewater treatment.

Originality/value

It is novel to optimize the combination of electrode and electrolyte to improve the efficiency of electroflocculation, which can be widely used in the actual wastewater treatment process.

Details

Pigment & Resin Technology, vol. 50 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 20 May 2020

Weiwei Lv, Zhijie Huangfu, Kangkang Wang, Wei Zhang and Jiming Yao

Indirect electrochemical oxidation and electro-flocculation were combined to degrade indigo wastewater.

Abstract

Purpose

Indirect electrochemical oxidation and electro-flocculation were combined to degrade indigo wastewater.

Design/methodology/approach

The degradation efficiency of indigo wastewater in single-cell and double-cell were investigated. Based on the previous single factor experiments, the oxidative degradation conditions of indigo wastewater in single cell were optimized by response surface methodology (RSM). The decolorization rate, chemical oxygen demand (COD) removal rate, the contents of flocculation precipitation and indigo were measured and analyzed.

Findings

The degradation efficiency in single cell was higher than in double cell. The electrolysis conditions were optimized by RSM and the decolorization rate was 99.01% with COD removal rate of 60.34% and conductivity of 89.75 mS/cm. The amount of flocculated precipitation decreased by 53.33% and the indigo increased by 86.34%. The content of Na and S decreased by 12.13 and 6.49%, respectively. The ratio of Fe3+ to Fe2+ in the solution was 4.62:1, indicating that most of the iron dropped on the electrode sheet was converted to Fe3+.

Research limitations/implications

The one-step electrochemical oxidation and flocculation method with the advantages of simple operation and environmental protection, provided a reference for the actual treatment of dyeing wastewater.

Practical implications

Combining the electrochemical flocculation and oxidation provided an efficient and practical solution for degradation of indigo wastewater.

Originality/value

Combining the advantages of electrochemical oxidation and electroflocculation, the application of electrochemistry in printing and dyeing wastewater treatment technology has been expanded.

Details

Pigment & Resin Technology, vol. 50 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 15 October 2019

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.

Details

Pigment & Resin Technology, vol. 49 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 12 July 2021

Xiaoyan Li, Zhihui Zhang, Jiming Yao, MengQian Wang and Na Yang

To improve the problems as the heavy burden of sewage treatment and environmental pollution caused by the traditional sodium hydrosulfite reduction dyeing of indigo, this study…

Abstract

Purpose

To improve the problems as the heavy burden of sewage treatment and environmental pollution caused by the traditional sodium hydrosulfite reduction dyeing of indigo, this study aims to carry out the direct electrochemical reduction dyeing for indigo with the eco-friendly Cu(II)/sodium borohydride reduction system under normal temperature and pressure conditions.

Design/methodology/approach

The electrochemical behavior of Cu(II)/sodium borohydride reduction system was investigated by cyclic voltammetry. And, the dyeing performance of the Cu(II)/sodium borohydride reduction system was developed by optimizing the concentration of copper sulfate in the anode electrolyte, applied voltage and reduction time via single-factor and orthogonal integrated analysis.

Findings

The dyeing performance of the Cu(II)/sodium borohydride reduction system is superior to that of the traditional reduction dyeing with sodium hydrosulfite. In the case of the optimized condition, the soaping fastness and dry/wet rubbing fastness of the dyed fabric in the two reduction dyeing processes were basically comparable, the K/S value of electrocatalytic reduction of indigo by Cu(II)/NaBH4 is 11.81, which is higher than that obtained by traditional sodium hydrosulfite reduction dyeing of indigo.

Originality/value

The innovative electrocatalytic reduction system applied herein uses sodium borohydride as the hydrogen source combined with Cu(II) complex as the catalyst, which can serve as a medium for electron transfer and active the dye molecule to make it easier to be reduced. The electrochemical dyeing strategy presented here provides a new idea to improve the reduction dyeing performance of indigo by sodium borohydride.

Details

Pigment & Resin Technology, vol. 51 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 24 October 2023

Raphael Kanyire Seidu, Benjamin Eghan, Emmanuel Abankwah Ofori, George Kwame Fobiri, Alex Osei Afriyie and Richard Acquaye

The purpose of this study is to investigate the physical, ultraviolet (UV), colour appearance and colour fastness properties of selected fabrics dyed with natural dyes from Daboya…

Abstract

Purpose

The purpose of this study is to investigate the physical, ultraviolet (UV), colour appearance and colour fastness properties of selected fabrics dyed with natural dyes from Daboya and Ntonso communities of Ghana. The study further highlights the rich cultural heritage of traditional dyeing from these two communities. Craftsmen in West Africa especially Ghana, have sustained the traditional dyeing methods to produce textile products for consumers.

Design/methodology/approach

In this study, two sample fabrics were purchased from craftsmen at Ntonso and Daboya communities in Ghana. These fabrics were analysed at the laboratory under standard test methods for their physical, UV, colour appearance and colour fastness properties.

Findings

Results showed that all the sample fabrics have good UV shielding performance (ratings above 50+). Daboya sample fabrics (dyed with indigo dyes) produced more colour stains than the sample fabrics from Ntonso (dyed with black “kuntunkuni” dyes). The K/Ssum value or colour yield reduced after washing but that alternatively increased the calculated ultraviolet protection factor.

Practical implications

Findings from this study exposed the unique UV performance of dyed traditional fabrics (using natural dyes) from Ntonso and Daboya communities in Ghana. This inspires and enforces the need for craftsmen to improve their production cycle to produce these fabrics in different sizes which provides the necessary UV shielding abilities for consumers in the wake of climate changes.

Originality/value

This study demonstrated that the natural dyeing process at the two communities produced relatively good UV and colour fastness properties of the sample fabrics. These eco-friendly dyeing practices have survived over time to maintain and promote the concept of sustainability within the textile and fashion industry in Ghana.

Details

Research Journal of Textile and Apparel, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1560-6074

Keywords

Article
Publication date: 8 December 2020

Xiaoyan Li, MengQian Wang, Gang Wu and Jiming Yao

The purpose of this study is to improve the performance of sodium borohydride in reducing indigo at room temperature, the divalent copper ion complex was combined with…

Abstract

Purpose

The purpose of this study is to improve the performance of sodium borohydride in reducing indigo at room temperature, the divalent copper ion complex was combined with electrochemical technology for the reduction of indigo by sodium borohydride.

Design/methodology/approach

According to the K/S value of the dyed cloth sample, find a more suitable ligand for the copper ion in the catholyte. Response surface analysis tests were performed to evaluate the effects of sodium borohydride concentration, sodium hydroxide concentration and copper sulfate pentahydrate concentration on the reduction potential of the dye solution and the K/S value of the dyed fabric samples.

Findings

Sodium gluconate was found to be a more suitable ligand for copper ions in catholyte. The effects of NaOH concentration as well as the interaction of NaBH4 and NaOH on the reduction potential of the catholyte and the K/S value of the dyed fabric samples were extremely significant. The optimal concentrations of NaBH4, NaOH and CuSO4•5H2O were 0.5, 2.5 and 0.65 g/L. In the case of the optimized condition, the absolute value of the reduction potential was 968, and the K/S value was 11.92, which is comparable with that of the conventional reduction process with sodium dithionite.

Originality/value

The divalent copper ion complex combined with electrochemical technology was applied in the process of reducing indigo with NaBH4 at room temperature.

Details

Pigment & Resin Technology, vol. 50 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 2 February 2024

Dawu Shu, Shaolei Cao, Yan Zhang, Wanxin Li, Bo Han, Fangfang An and Ruining Liu

This paper aims to find a suitable solution to degrade the C.I. Reactive Red 24 (RR24) dyeing wastewater by using sodium persulphate to recycle water and inorganic salts.

Abstract

Purpose

This paper aims to find a suitable solution to degrade the C.I. Reactive Red 24 (RR24) dyeing wastewater by using sodium persulphate to recycle water and inorganic salts.

Design/methodology/approach

The effects of temperature, the concentration of inorganic salts and Na2CO3 and the initial pH value on the degradation of RR24 were studied. Furthermore, the relationship between free radicals and RR24 degradation effect was investigated. Microscopic routes and mechanisms of dye degradation were further confirmed by testing the degradation karyoplasmic ratio of the product. The feasibility of the one-bath cyclic dyeing in the recycled dyeing wastewater was confirmed through the properties of dye utilization and color parameters.

Findings

The appropriate conditions were 0.3 g/L of sodium persulphate and treatment at 95°C for 30 min, which resulted in a decolorization rate of 98.4% for the dyeing wastewater. Acidic conditions are conducive to rapid degradation of dyes, while ·OH or SO4· have a destructive effect on dyes under alkaline conditions. In the early stage of degradation, ·OH played a major role in the degradation of dyes. For sustainable cyclic dyeing of RR24, inorganic salts were reused in this dyeing process and dye uptake increased with the times of cycles. After the fixation, some Na2CO3 may be converted to other salts, thereby increasing the dye uptake in subsequent cyclic staining. However, it has little impact on the dye exhaustion rate and color parameters of dyed fabrics.

Originality/value

The recommended technology not only reduces the quantity of dyeing wastewater but also enables the recycling of inorganic salts and water, which meets the requirements of sustainable development and clean production.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 12 January 2021

Abhijit Majumdar and Sanjib Kumar Sinha

It has been long debated whether the three bottom lines of sustainability (economic, environmental and social) can be achieved simultaneously or whether achieving one adversely…

Abstract

Purpose

It has been long debated whether the three bottom lines of sustainability (economic, environmental and social) can be achieved simultaneously or whether achieving one adversely affects the others. This paper analyses the economic sustainability of an environmental initiative, namely, effluent treatment plant (ETP), adopted by an Indian textile industry.

Design/methodology/approach

Two situations have been considered for the analysis. First, pure economic view with the operating and installed capacities has been considered. Second, combined economic-environmental view using shadow prices of undesirable outputs (biological oxygen demand, chemical oxygen demand, total nitrogen, total phosphorous, etc.) has been analysed.

Findings

It has been found that when pure economic view is considered, the net present value (NPV) of the ETP with present operating capacity (10,200 kL/day) is negative, implying that it is not economically sustainable. However, if the ETP is operated with the full installed capacity (17,000 kL/day), it becomes economically sustainable except in the case of very high cost of capital (13%). Finally, when shadow prices of undesirable outputs are considered, the NPV becomes positive, bolstering the economic-environmental sustainability of ETP.

Research limitations/implications

In future, multiple case studies should be conducted in similar organisations to extend the general applicability of the outcome of this study. This research considers the economic and environmental aspects of ETP. However, social benefits have not been considered in this research work, which can definitely be addressed in future endeavours.

Practical implications

Though very high capital investment of ETP acts as a barrier, the results of this study imply that the top management of textile and clothing organisations should look at it from the holistic economic-environmental viewpoint. The use of ETP also leads to social benefits by improving the health of local community and by reducing their hospitalisation, medical expenditure and absenteeism from school and workplace. The outcome of this research may enthuse the entrepreneurs to adopt environmental initiatives.

Originality/value

The paper provides a framework to evaluate the economic feasibility of ETP by considering the time value of money. It is demonstrated with a real case that the environmental initiatives can be economically rewarding.

Details

Benchmarking: An International Journal, vol. 28 no. 6
Type: Research Article
ISSN: 1463-5771

Keywords

Content available
Article
Publication date: 1 December 2003

101

Abstract

Details

Pigment & Resin Technology, vol. 32 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

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