Simultaneous degradation of cephalexin, ciprofloxacin, and clarithromycin from medical laboratory wastewater by electro-Fenton process

https://doi.org/10.1016/j.jece.2020.104666Get rights and content

Highlights

  • Antibiotics removed from real medical laboratory wastewater by electro-Fenton.

  • Process parameters were optimized with central composite design.

  • Over 98 % of removal efficiencies were achieved at optimum conditions.

  • Electro-Fenton is effective in antibiotic removal from medical laboratory wastewater.

Abstract

This study aimed to investigate antibiotic removal from medical laboratory wastewater by the electro-Fenton (EF) process. The central composite design was applied as the statistical and mathematical method to determine the optimum process conditions. The system responses were Cephalexin, Ciprofloxacin, and Clarithromycin removal while initial pH, current, reaction time, and H2O2/COD ratio were independent variables. The correlation coefficients of all responses were above 80 % and they were sufficient and acceptable. Optimum operation conditions were pH 2.99, current 3.93 A, reaction time 35.3 min, and H2O2/COD ratio 1.09. The removal efficiencies obtained in validation experiments conducted at optimum conditions were 99.12 %, 98.65 %, and 99.38 % for Cephalexin, Ciprofloxacin, and Clarithromycin, respectively. As a result, it was determined that the response surface methodology is a suitable method for the optimization and design of electro-Fenton process parameters and the EF process is an efficient technology for removing antibiotics from medical laboratory wastewater.

Introduction

Health care facilities utilize a huge amount of water and generate wastewater including domestic wastes as well as medical and hazardous wastes based on the service provided by the facility [1]. Various laboratory services are provided in health care facilities depending on the class and extent of the establishment. The wastewater produced in these laboratories is rich in antibiotics, diagnostic materials, disinfectants, laboratory chemicals, and micropollutants [2,3]. Traditional treatment applications are usually not sufficient for the degradation of antibiotics present in the wastewater [4]. Therefore, they are released into the environment, which has become an emerging issue in the last decade [5]. The existence of antibiotics in the environment due to their persistence and stability may have toxic effects on human health [6]. Thus, novel technologies should be applied for the effective treatment of wastewaters containing antibiotics.

Numerous treatment techniques including coagulation, flocculation, filtration, sedimentation, adsorption, ultrasonication, and biological processes have been applied for the removal of emerging chemicals from water and wastewater [7]. Nonetheless, alternative methods are needed due to low removal efficiencies and high costs of some of these applications [8]. On the other hand, advanced oxidation processes (AOPs) which are effective to remove recalcitrant pollutants have gained increasing attention in antibiotic removal considering their strong oxidation capability and fast reaction rate [8]. AOPs such as Fenton, ozonation, photocatalytic oxidation, and electrooxidation have been used for the removal of antibiotics from water or wastewater [8,9].

Various types of antibiotics including fluoroquinolones, macrolides, and cephalosporin have been detected in wastewater globally [10]. Among these groups, Ciprofloxacin (CIP) and Clarithromycin (CLA) were implemented in the priority substances list and watch list for water bodies in the Directive 2013/39/EU [11] and Decision 2015/495/EU [12] while Cephalexin (CEX) is one of the most frequently prescribed antibiotics [13]. Biological treatment [14,15], adsorption [[16], [17], [18]], Fenton process [19,20], photochemical degradation [21], membrane biological reactor [22], and sonochemical treatment [23] are among the applied methods for the removal of CIP, CLA, and CEX from aqueous media. Besides, to the best of authors’ knowledge, there were no studies on the removal of CEX, CIP, and CLA by the EF process from hospital wastewater or wastewater from health care facilities. Thus, there is a need for researches considering alternative treatment methods including EF for antibiotic removal from such kind of wastewater.

The traditional approach for the optimization of process variables is performing the experiments by changing one parameter at each time. However, this causes a loss of materials, time, and human labor. Thus, using a statistical tool such as response surface methodology (RSM) has gain importance since it provides the optimization of process variables with a minimum number of experiments. RSM has been applied for the optimization of process variables in antibiotic removal from various wastewaters [[24], [25], [26], [27]]. Besides, it was applied for the optimization of CEX removal by sono-Fenton [28] and CIP removal by the EF [29] from synthetic water. However, there is a lack of a study on the removal and process optimization of CEX, CIP, and CLA from real medical laboratory wastewater by the EF process.

The electro-Fenton (EF) process, which is a combination of electrocoagulation, and traditional Fenton process is an effective oxidation method, especially in high strength wastewaters. During the EF process, Fe2+ ions are provided from sacrificial iron anodes [30,31] and more OH· radicals are generated which provides an advantage of both electrocoagulation and Fenton processes [[30], [31], [32], [33], [34]]. EF has been used for the degradation of various antibiotics in water [[35], [36], [37], [38]]. On the other hand, there were only a few studies concerning the removal of CEX [39], CIP [[40], [41], [42]], and CLA [43] by electro-Fenton or Fenton based treatments. The encountered studies were conducted by synthetic water and to the best of authors’ knowledge; there were no studies on CEX, CIP, and CLA removal from hospital wastewater or such a kind of wastewater by the EF process. The present study is among the first attempts to remove CEX, CIP, and CLA from medical laboratory wastewater by the EF process. The EF process becomes prominent in terms of ease of application, high pollutant removal efficiency, and comparatively moderate cost at optimized conditions. The present study will provide an insight into the usage of the EF process for the removal of CEX and CLA as well as contribute to the limited researches on CIP removal by the EF process. In this study, removal of Cephalexin, Ciprofloxacin, and Clarithromycin from medical laboratory wastewater by the electro-Fenton process was investigated. This study provides both the application of the EF process for CEX, CIP and CLA removal in wastewater with high toxic strength and optimization of process parameters. The process variables were optimized with central composite design and the optimum conditions for antibiotics removal by the electro-Fenton process were determined.

Section snippets

Wastewater characterization

The wastewater used in this study was taken from a medical laboratory's wastewater tank in İstanbul, Turkey. The medical laboratory serves 11 different health care facilities. Approximately 4−5 m3 day−1 of wastewater is generated in the laboratory which is collected in a 25 m3 capacity tank and no domestic wastewater is mixed in this wastewater tank. The wastewater used in the present study was taken when the volume of wastewater in the tank was about 10 m3, which represents a composite sample

Results and discussion

The suitability of the experimental data to the polynomial model representing Cephalexin, Ciprofloxacin, and Clarithromycin removal efficiencies (%) (response Y) as a function of pH, current, reaction time, and H2O2/COD ratio were analyzed using the Statgraphics Centurion XVI.I software and the model equations are given below.CEXremoval,%=+97.82-0.5417pH+0.5167Current+0.9250Reactiontime+1.35H2O2/COD-0.45pHCurrent-0.15pHReactiontime+0.4125pHH2O2/COD+0.4750CurrentReactiontime-

Conclusions

In this study, wastewater occurring in a medical laboratory serving 11 different health care facilities was treated with the EF process. The removal performance of antibiotics was evaluated and process parameters were optimized applying central composite design. The optimized process variables were pH 2.99, current 3.93 A, reaction time 35.3 min, and H2O2/COD ratio 1.09. Among the linear parameters, the H2O2/COD ratio has the highest effect on CEX, CIP, and CLA removal by the EF process. The

CRediT authorship contribution statement

Irfan Basturk: Methodology, Validation, Investigation. Gamze Varank: Conceptualization, Investigation, Methodology, Supervision, Writing - original draft. Selda Murat-Hocaoglu: Conceptualization, Investigation, Methodology, Supervision. Senem Yazici-Guvenc: Software, Formal analysis, Visualization. Emine Can-Güven: Investigation, Writing - original draft. Elmas Eva Oktem-Olgun: Methodology, Validation. Oltan Canli: Methodology, Validation.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This research was supported by the Ministry of Environment and Urbanization with the project entitled “Treatment and Management of Liquid Wastes and Wastewater from Healthcare Facilities” and by Yildiz Technical University-The Scientific Research Projects Coordinatorshipwith the research project number of FDK-2018-3426.

References (85)

  • M. Bizi et al.

    Evaluation of the ciprofloxacin adsorption capacity of common industrial minerals and application to tap water treatment

    Powder Technol.

    (2020)
  • A. Hassani et al.

    Preparation of magnetite nanoparticles by high-energy planetary ball mill and its application for ciprofloxacin degradation through heterogeneous Fenton process

    J. Environ. Manage.

    (2018)
  • D. Dolar et al.

    Removal of emerging contaminants from municipal wastewater with an integrated membrane system, MBR--RO

    J. Hazard. Mater.

    (2012)
  • J.C. Murillo-Sierra et al.

    Sulfamethoxazole mineralization by solar photo electro-Fenton process in a pilot plant

    Catal. Today

    (2018)
  • J. Wu et al.

    Application of response surface methodology to the removal of the antibiotic tetracycline by electrochemical process using carbon-felt cathode and DSA (Ti/RuO2--IrO2) anode

    Chemosphere.

    (2012)
  • M. Shoorangiz et al.

    Optimized electro-Fenton process with sacrificial stainless steel anode for degradation/mineralization of ciprofloxacin

    Process Saf. Environ. Prot.

    (2019)
  • A. Akyol et al.

    A comparative study of electrocoagulation and electro-Fenton for treatment of wastewater from liquid organic fertilizer plant

    Sep. Purif. Technol.

    (2013)
  • J. Virkutyte et al.

    Optimisation of Electro-Fenton denitrification of a model wastewater using a response surface methodology

    Bioresour. Technol.

    (2010)
  • Z. Qiang et al.

    Electrochemical regeneration of Fe2+ in Fenton oxidation processes

    Water Res.

    (2003)
  • A.F. Martins et al.

    Nonylphenol polyethoxylate degradation by means of electrocoagulation and electrochemical Fenton

    Sep. Purif. Technol.

    (2006)
  • H. Liu et al.

    Kinetic modeling of electro-Fenton reaction in aqueous solution

    Water Res.

    (2007)
  • C. Annabi et al.

    Degradation of enoxacin antibiotic by the electro-Fenton process: optimization, biodegradability improvement and degradation mechanism

    J. Environ. Manage.

    (2016)
  • X. Liu et al.

    Insight into electro-Fenton and photo-Fenton for the degradation of antibiotics: mechanism study and research gaps

    Chem. Eng. J.

    (2018)
  • A. Ledezma Estrada et al.

    Biodegradability enhancement of wastewater containing cefalexin by means of the electro-Fenton oxidation process

    J. Hazard. Mater.

    (2012)
  • A. Huang et al.

    Effect of Fe2+, Mn2+ catalysts on the performance of electro-Fenton degradation of antibiotic ciprofloxacin, and expanding the utilizing of acid mine drainage

    Sci. Total Environ.

    (2020)
  • X. Mi et al.

    Electro-Fenton degradation of ciprofloxacin with highly ordered mesoporous MnCo2O4-CF cathode: enhanced redox capacity and accelerated electron transfer

    Chem. Eng. J.

    (2019)
  • X. Zhu et al.

    Optimization of fenton and electro-fenton oxidation of biologically treated coking wastewater using response surface methodology

    Sep. Purif. Technol.

    (2011)
  • K. Yetilmezsoy et al.

    Response surface modeling of Pb (II) removal from aqueous solution by Pistacia vera L.: box--behnken experimental design

    J. Hazard. Mater.

    (2009)
  • S. Ahmadzadeh et al.

    Modeling and kinetics study of electrochemical peroxidation process for mineralization of bisphenol A; a new paradigm for groundwater treatment

    J. Mol. Liq.

    (2018)
  • A. Babuponnusami et al.

    A review on Fenton and improvements to the Fenton process for wastewater treatment

    J. Environ. Chem. Eng.

    (2014)
  • P. Bansal et al.

    Synergistic effect of dual process (photocatalysis and photo-Fenton) for the degradation of Cephalexin using TiO2 immobilized novel clay beads with waste fly ash/foundry sand

    J. Photochem. Photobiol. A: Chem.

    (2017)
  • P. Karaolia et al.

    Reduction of clarithromycin and sulfamethoxazole-resistant Enterococcus by pilot-scale solar-driven Fenton oxidation

    Sci. Total Environ.

    (2014)
  • I. Kim et al.

    Performance of UV and UV / H 2 O 2 processes for the removal of pharmaceuticals detected in secondary effluent of a sewage treatment plant in Japan

    J. Hazard. Mater.

    (2009)
  • Y. Lee et al.

    Prediction of micropollutant elimination during ozonation of a hospital wastewater effluent

    Water Res.

    (2014)
  • A. Gupta et al.

    Degradation of ciprofloxacin using Fenton’s oxidation: effect of operating parameters, identification of oxidized by-products and toxicity assessment

    Chemosphere.

    (2018)
  • M. Salari et al.

    Degradation of ciprofloxacin antibiotic by Homogeneous Fenton oxidation: hybrid AHP-PROMETHEE method, optimization, biodegradability improvement and identification of oxidized by-products

    Chemosphere.

    (2018)
  • A.S. Giri et al.

    Decomposition of drug mixture in Fenton and photo-Fenton processes: comparison to singly treatment, evolution of inorganic ions and toxicity assay

    Chemosphere

    (2015)
  • S.K. Mondal et al.

    Removal of ciprofloxacin using modified advanced oxidation processes: kinetics, pathways and process optimization, J. Clean

    Prod.

    (2018)
  • M.S. Yahya et al.

    Oxidative degradation study on antimicrobial agent ciprofloxacin by electro-fenton process: kinetics and oxidation products

    Chemosphere.

    (2014)
  • Y. Li et al.

    Synergistic degradation of antimicrobial agent ciprofloxacin in water by using 3D CeO2/RGO composite as cathode in electro-Fenton system

    J. Electroanal. Chem. Lausanne (Lausanne)

    (2017)
  • V. Rani et al.

    Fabrication of reduced graphene oxide-graphite paste electrode for H2O2 formation and its implication for ciprofloxacin degradation

    Surf. Interfaces

    (2017)
  • G. Divyapriya et al.

    Ferrocene functionalized graphene based electrode for the electro−Fenton oxidation of ciprofloxacin

    Chemosphere.

    (2018)
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