Water recovery from yarn fabric dyeing wastewater using electrochemical oxidation and membrane processes

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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Osmotically and thermally driven membrane processes for enhancement of water recovery in desalination processes

Desalination and Water Treatment ◽

10.5004/dwt.2010.1760 ◽

2010 ◽

Vol 15 (1-3) ◽

pp. 279-286 ◽

Cited By ~ 35

Author(s):

Tzahi Y. Cath

Keyword(s):

Water Recovery ◽

Membrane Processes ◽

Thermally Driven

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Optimization of the electrochemical oxidation of textile wastewater by graphite electrodes by response surface methodology and artificial neural network

Water Science & Technology ◽

10.2166/wst.2021.240 ◽

2021 ◽

Author(s):

Mohammed Saleh ◽

Rabia Yildirim ◽

Zelal Isik ◽

Ahmet Karagunduz ◽

Bulent Keskinler ◽

...

Keyword(s):

Neural Network ◽

Artificial Neural Network ◽

Response Surface Methodology ◽

Response Surface ◽

Electrochemical Oxidation ◽

Experimental Results ◽

Dyeing Wastewater ◽

Optimum Conditions ◽

Graphite Electrodes ◽

Artificial Neural

Abstract In this study, electrochemical oxidation of combed fabric dyeing wastewater was investigated using graphite electrodes. The response surface methodology (RSM) was used to design the experiments via the central composite design (CCD). The planned experiments were done to track color changes and chemical oxygen demand (COD) removal. The experimental results were used to develop optimization models using RSM and the artificial neural network (ANN) and they were compared. The developed models by the two methods were in good agreement with the experimental results. The optimum conditions were found at 150 A/m2, pH 5, and 120 min. The removal efficiencies for color and COD reached 96.6% and 77.69%, respectively. The operating cost at the optimum conditions was also estimated. The energy and the cost of 1 m3 of wastewater required 34.9 kWh and 2.58 US$, respectively. The graphite electrodes can be successfully utilized for treatment of combed fabric dyeing wastewater with reasonable cost.

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Membrane Crystallization and Membrane Condenser: Two Membrane Contactor Applications

10.47890/jcsce/2020/mfrappa/10082116 ◽

2020 ◽

Vol 1 (3) ◽

Author(s):

Frappa M ◽

◽

Li X ◽

Drioli E ◽

Macedonio F ◽

...

Keyword(s):

Membrane Distillation ◽

Current Status ◽

Water Recovery ◽

Membrane Processes ◽

Gas Streams ◽

Development Direction ◽

Salt Crystals ◽

Industrial Gases ◽

Pre Treatment ◽

Application Fields

In recent years different new membrane processes have been designed and developed. In this paper two innovative processes (i.e., membrane condenser and membrane crystallization) will be described and discussed. Membrane crystallization can be used in desalination in combination with membrane distillation and pressure driven membrane processes (such as nanofiltration or reverse osmosis) to achieve high recovery factor combined to salt crystals production.The innovative membrane condenser can be used for the selective recovery of evaporated waste water and contaminants from industrial gases. This process can be also used for pre-treating gas streams that require further separation for the recovery of a defined species (such as pre-treatment of flue gas when used for CO2 capture, biogas for bio methane production, etc.). The current status, the separation principle, the utilized membrane materials and membrane configurations, and the application fields are described and discussed. The future development direction of these two processes is also given. Keywords: Membrane Crystallization; Membrane Condenser; Water recovery; Membrane Technologies;

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