Combining fluidized metal-impregnated granular activated carbon in three-dimensional electrocoagulation system: Feasibility and optimization test of color and COD removal from real cotton textile wastewater

https://doi.org/10.1016/j.seppur.2015.03.043Get rights and content

Highlights

  • Color and COD removal from cotton textile wastewater was performed.

  • Metal (Al and Fe) impregnated GAC was applied as a moving particle electrode.

  • MIGAC-TEC system exhibited high color and COD removal efficiencies.

  • Optimal key parameters were determined by RSM with a CCD.

  • Decolorization and COD removal efficiency were statistically maximized.

Abstract

The present study focused on the treatment of real cotton textile wastewater by combining metal (Al/Fe)-impregnated granular activated carbon (MIGAC) as moving particle electrodes in electrocoagulation, referred to here as the MIGAC-TEC system. The feasibility test clearly indicated that MIGAC significantly accelerated the decolorization and COD removal efficiency. The effects of four parameters: applied voltage, initial pH, MIGAC dosage, and reaction time on the percentage of color and COD removal were investigated using response surface methodology with a central composite design. As results, it was found that the decolorization (R2 = 0.9576) and COD removal (R2 = 0.9395) were well fitted by a developed quadratic polynomial models and the initial pH was the most influential factor. Through numerical optimization, highly acceptable removal performances of 99.13 ± 0.21% decolorization and 97.01 ± 0.18% COD removal efficiency were achieved under statistically optimized conditions, and suggested that the developed system is a very suitable technique for the enhancement of electrocoagulation-based cotton textile wastewater treatment.

Introduction

The wastewater from textile and dyeing industries has serious negative effects on both the aquatic ecosystems and human health, raising wide concerns and also causes problems at conventional biological wastewater treatment plants due to their various organic and inorganic chemical compounds. Cotton textile processing alone consumes and discharges huge amounts of water, estimated to be about 40–65 L per kg cloth produced [1]. Cotton textile industry wastewater is generated from cotton fiber, washing, dyeing and finishing stages. Considering both volume generated and effluent properties, such as chemical stability, non-biodegradability, and toxic and carcinogenic characteristics, textile industry wastewater is ranked as the most polluting sector [2], [3], [4]. Therefore, treatment of textile wastewater is a prerequisite to its release into water streams. Various treatment methods have been widely applied to remove color and organic pollutants from textile wastewater using biological, physical, chemical methods, and their combination. However, up to the present, most of these have been insufficient in terms of removal efficiency and economic burden [5], [6], [7], [8]. On the other hand, in recent years, the electrocoagulation process has attracted great attention as one of the promising and powerful ways to treat pollutants from wastewater, due to its unique advantages, such as its lack of chemical additives, simple operation, high efficiency, reduced sludge production, and robustness to various wastewaters [9], [10], [11], [12].

In the conventional electrocoagulation technique, the single electrodes such as Fe–Fe and Al–Al, or combined electrodes such as Al–Fe or Fe–Al, which are called a two-dimensional electrode system, have been widely applied to water and wastewater treatment [13]. It has been reported that the combined Al–Fe or Fe–Al electrodes exhibit better performance, removing pollutants at higher efficiencies than the single electrode systems [14]. The electrocoagulation process is based on the electrochemical formation of metal ions such as Al and Fe, which act as destabilizing agents and lead to the neutralization of electric charge for removing pollutants. In combination electrocoagulation using Al and Fe electrode, the isomorphous substitution of Fe3+ ions by Al3+ ions in iron oxides also disrupts crystallization, resulting in a larger surface area of the total adsorbents (oxide mineral), which can increase removal performance [15]. However, during electrocoagulation with a two-dimensional electrode system, the target pollutant removal efficiency strongly depends on the distance between the electrodes and the conductivity between the electrode and target pollutant, because the electric field technique involves heterogeneous electron transfer. That means that a higher electron transfer rate and higher electric field are required to achieve acceptable removal efficiency for the application of a large scale electrocoagulation system [16].

Recently, as an alternative technique, a three-dimensional electrode process combining with carbon particles, has been recommended and has been proven to be an effective way to significantly enhance the specific surface area of the working electrode [8], [17], [18], [19], [20]. It is thus expected that three-dimensional electrocoagulation would be an ideal choice for textile wastewater treatment. However, to our best knowledge, there are no reported data in the literature on the use of metal (a combination of Al and Fe) impregnated granular activated carbon (MIGAC) in a three-dimensional electrocoagulation system, which in this investigation is called a MIGAC-TEC (Metal Impregnated Granular Activated Carbon-Three dimensional ElectroCoagulation) system. This system was created based on the idea of using metal (Al or Fe and both Al/Fe) impregnated carbon particles as adsorbent and metal-support [21], [22]. In addition, the MIGAC-TEC system was basically constructed as a fluidized bed reactor, combining DC power with stirred granular activated carbon (GAC) particles as a moving electrode. This configuration provides some advantages as compared with a fixed or packed bed reactor, including simple construction, low capital cost, and a high contact rate between particles and pollutants [23]. We hypothesized that the metal impregnation of the GAC may create an interesting way to achieve efficient color and COD removal from cotton textile wastewater by employing the collaborative action of Al and Fe. In this paper, we present results showing that MIGAC containing mixed Al and Fe oxides exhibited more effective and efficient decolorization and COD removal than raw GAC addition in both batch and repeat recycling test. The textural properties of MIGAC were monitored and operational parameters of the MIGAC-TEC system (i.e., applied voltage, initial pH, MIGAC dosage, and reaction time) were statistically and mathematically optimized using response surface methodology (RSM).

Section snippets

Cotton textile wastewater

Cotton textile wastewater was collected from the wastewater storage tank of a local cotton textile wastewater treatment plant in Seoul, Republic of Korea, and then directly stored at below 4 °C in a dark condition to avoid any change in physico-chemical characteristics before use. Before conducting the electrochemical experiments, the relatively large suspended particles in the colloidal ranges were removed from the wastewater by screening with 45 um in pore diameter mesh. The cotton textile

Textural properties of MIGAC

The measured nitrogen adsorption and desorption isotherms for raw GAC and MIGAC are plotted together in Fig. 1(A), for comparison of those textural properties. As can be seen in Fig. 1(A), a steep increase of nitrogen adsorption at very low P/P0 values (≈0.0) was observed, which proves a significant presence of narrow microporosity in the both raw GAC and MIGAC. According to the IUPAC (International Union of Pure and Applied Chemistry) classification, it follows that their shape these isotherms

Conclusion

This present study mainly focused on the application of the MIGAC-TEC system for decolorization and COD removal from cotton textile wastewater, and its statistical optimization. A comparison of GAC-TEC and MIGAC-TEC systems in the feasibility and repeat test clearly confirmed that the use of MIGAC as a moving particle electrocoagulation electrode in a three-dimensional electrocoagulation process provides an effective alternative method. The XRD analysis of byproducts revealed that the increase

Acknowledgement

This work was supported by Grants from the Korea Research Council of Fundamental Science and Technology (Project No. 2N38090).

References (58)

  • J. Racyte et al.

    Combining fluidized activated carbon with weak alternating electric field for disinfection

    Carbon

    (2011)
  • L. Xu et al.

    Electrolytic treatment of C.I. Acid Orange 7 in aqueous solution using a three-dimensional electrode reactor

    Dyes Pigments

    (2008)
  • E. Fockedey et al.

    Coupling of anodic and cathodic reactions for phenol electro-oxidation using three-dimensional electrodes

    Water Res.

    (2002)
  • F. Tisa et al.

    Applicability of fluidized bed reactor in recalcitrant compound degradation through advanced oxidation processes: a review

    J. Environ. Manage.

    (2014)
  • A.R. Khataee et al.

    Photocatalytic treatment of a dye solution using immobilized TiO2 nanoparticles combined with photoelectron-Fenton process: optimization of operational parameters

    J. Electroanal. Chem.

    (2010)
  • K.W. Jung et al.

    Application and optimization of electric field-assisted ultrasonication for disintegration of waste activated sludge using response surface methodology with a Box–Behnken design

    Ultrason. Sonochem.

    (2015)
  • M. Olivares-Marín et al.

    Preparation of activated carbon from cherry stones by physical activation in air. Influence of the chemical carbonization with H2SO4

    J. Anal. Appl. Pyrol.

    (2012)
  • A. Barroso-Bogeat et al.

    Preparation of activated carbon-metal oxide hybrid catalysts: textural characterization

    Fuel Process. Technol.

    (2014)
  • J.S. Choi et al.

    Direct synthesis of phenol from benzene on iron-impregnated activated carbon catalysts

    Appl. Catal., A

    (2005)
  • V. Gaur et al.

    Catalytic oxidation of toluene and m-xylene by activated carbon fiber impregnated with transition metals

    Carbon

    (2005)
  • J. Ren et al.

    Granulation and ferric oxides loading enable biochar derived from cotton stalk to remove phosphate from water

    Bioresour. Technol.

    (2015)
  • C.J. Israilides et al.

    Olive oil wastewater treatment with the use of an electrolysis system

    Bioresour. Technol.

    (1997)
  • S.H. Lin et al.

    Saline wastewater treatment by electrochemical method

    Water Res.

    (1998)
  • A.G. Vlyssides et al.

    Electrochemical treatment of vinasse from beet molasses

    Water Sci. Technol.

    (1997)
  • J.A.G. Gomes et al.

    Aresenic removal by electrocoagulation using combined Al–Fe electrode system and characterization of products

    J. Hazard. Mater.

    (2007)
  • N.S. Abuzaid et al.

    Ground water coagulation using soluble stainless steel electrodes

    Adv. Environ. Res.

    (2002)
  • M.Y.A. Mollah et al.

    Fundamentals, present and future perspectives of electrocoagulation

    J. Hazard. Mater.

    (2004)
  • O.T. Can et al.

    Treatment of the textile wastewater by combined electrocoagulation

    Chemosphere

    (2006)
  • N. Daneshvar et al.

    Decolorization of basic dye solutions by electrocoagulation: an investigation of the effect of operational parameters

    J. Hazard. Mater.

    (2006)
  • Cited by (52)

    • In-situ preparation of biochar-loaded particle electrode and its application in the electrochemical degradation of 4-chlorophenol in wastewater

      2021, Chemosphere
      Citation Excerpt :

      The surfaces of the filled conductive particles are charged. As a result, the mass transfer efficiency is improved, and the treatment of pollutants is enhanced (Zhang C et al., 2013; Jung K.W et al., 2015; Palma-Goyes R E et al., 2015). Activated carbon is most commonly used in the filling materials of three-dimensional electrode systems.

    • Preparation of Sn/Mn loaded steel slag zeolite particle electrode and its removal effect on rhodamine B(RhB)

      2020, Journal of Water Process Engineering
      Citation Excerpt :

      ii) with the increase of current intensity, the reactor can polarize more particle electrodes, thereby enhancing the redox process and electrical adsorption capacity of the particle electrode surface, and promoting the heterogeneous catalysis of the particle electrode surface [31]. In addition, the larger the number of microelectrodes, the wider the reaction area, and the stronger the free radicals produced [32]. Therefore, 0.500 A was selected as the optimal current intensity in this experiment.

    View all citing articles on Scopus
    View full text