Electrochemical Remediation Technologies for Waters Contaminated by Pharmaceutical Residues
01 Jan 2012-pp 297-346
TL;DR: In this article, the authors present an overview on electrochemical methods devised for the removal of pharmaceutical residues from both synthetic solutions and real pharmaceutical wastewaters, and discuss the routes for the complete degradation of the initial pollutants.
Abstract: The presence of pharmaceutical micropollutants in the environment has become of major concern in the last decades. Many electrochemical technologies are currently available for the remediation of waters contaminated by refractory organic pollutants. They are mainly defined as eco-friendly water treatments since the main reagent involved is a clean species, the electron. Recent reviews have focused on the destruction of pharmaceutical residues by the application of methods like ozonation and advanced oxidation processes. Here, we present an overview on electrochemical methods devised for the removal of pharmaceutical residues from both synthetic solutions and real pharmaceutical wastewaters. The fundamentals and experimental set-ups involved in different technologies such as electrocoagulation, anodic oxidation, electro-oxidation with active chlorine, electro-Fenton, photoelectro-Fenton, and photoelectrocatalysis, among others, are discussed. Progress on the promising solar photoelectro-Fenton process devised and further developed in our laboratory is especially highlighted and documented. The destruction of the individual pharmaceuticals and the abatement of total organic carbon or reduction of chemical oxygen demand allow the comparison between the different methods. In some cases, the routes for the complete degradation of the initial pollutants are discussed.
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TL;DR: In this paper, an alternative strategy to dispose and reuse spent inorganic adsorbents is proposed, where the authors synthesized CoO/CuFe2O4 mixed metal oxide from layered double hydroxides by a modified co-precipitation and calcination method at 500°C for 5h.
Abstract: Health concerns have been raised over the excessive occurrences of antibiotics such as tetracycline in aquatic environments. Adsorption is a simple and cheap technique for the removal of pharmaceuticals from industrial wastewater. To date, limited information exists on the fate, economical treatment and safe disposal of spent adsorbents in the environment, and this is often considered as the main drawback of adsorption. In this article, an alternative strategy to dispose and reuse spent inorganic adsorbents is proposed. We synthesized CoO/CuFe2O4 mixed metal oxide from layered double hydroxides by a modified co-precipitation and calcination method at 500 °C for 5 h. CoO/CuFe2O4 has a 348.5 m2/g surface area, pH point zero charge of 5.8 and an average pore diameter of 5.8 nm. Results show that the tetracycline removal efficiency at pH 6 reached 96.6% and 84–87.3% in the absence and in the presence of 4 g/L competing ions (Cl− and NO3−), respectively. Moreover, CoO/CuFe2O4 retained stable activities, of about 90%, over five consecutive recycling runs. Spent CoO/CuFe2O4 was reused as a catalyst in the presence of sunlight for degradation of azo dye, and this is the first report of achieving ~ 77% discolouration of eriochrome black T dye using a recycled adsorbent.
52 citations
Cites background from "Electrochemical Remediation Technol..."
...A substantial number of antibiotics have been frequently detected in sludge, soil and different types of waters (drinking water, wastewater, groundwater, surface water) (Brillas and Sirés 2012; Cizmas et al. 2015; Tijani et al. 2016; Oladipo et al. 2018a)....
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...A substantial number of antibiotics have been frequently detected in sludge, soil and different types of waters (drinking water, wastewater, groundwater, surface water) (Brillas and Sirés 2012; Cizmas et al....
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TL;DR: Oxidation of gray water on mixed metal oxide anodes could not be recommended as a post-treatment step for gray water treatment according to the results of this study.
Abstract: Electrochemical conversion of micropollutants in real gray water effluent was studied for the first time. Six compounds that are frequently found in personal care and household products, namely methylparaben, propylparaben, bisphenol A, triclosan, galaxolide, and 4- methylbenzilidene camphor (4-MBC), were analyzed in the effluent of the aerobic gray water treatment system in full operation. The effluent was used for lab-scale experiments with an electrochemical cell operated in batch mode. Three different anodes and five different cathodes have been tested. Among the anodes, Ru/Ir mixed metal oxide showed the best performance. Ag and Pt cathodes worked slightly better than Ti and mixed metal oxide cathodes. The compounds that contain a phenolic ring (parabens, bisphenol A, and triclosan) were completely transformed on this anode at a specific electric charge Q = 0.03 Ah/L. The compounds, which contain a benzene ring and multiple side methyl methyl groups (galaxolide, 4-MBC) required high energy input (Q ≤...
36 citations
01 Jan 2016
TL;DR: In this paper, a review of physico-chemical techniques applied to pollutants for their removal from wastewater is given, where a particular focus is given to coagulation-flocculation, chemical precipitation, ion exchange, adsorption, membrane filtration and electrochemical treatments.
Abstract: This chapter reviews various physico–chemical techniques applied to pollutants for their removal from wastewater. A particular focus is given to coagulation–flocculation, chemical precipitation, ion exchange, adsorption, membrane filtration and electrochemical treatments. The main particularities, advantages and disadvantages of the described techniques are presented. Coagulation–flocculation and chemical precipitation can be applied for the treatment of wastewater with metal concentrations higher than 1000 mg/L. Ion exchange and adsorption are recognized as effective and economic methods of pollutant removal from wastewaters at pollutants concentrations in the range of <10–100 mg/L. Membrane filtration and electrochemical treatment can only be feasible for special technological tasks because of their high costs.
30 citations
TL;DR: In this article, the effects of three parameters such as pH (4-10), current density (i=20-80 mA/cm), and time of reaction (t=10-30 min) were evaluated using a response surface methodology and in particular a full factorial central composite face-centered (CCF) design.
Abstract: The present work was conducted to optimize operating parameters for electrocoagulation treatment of a pharmaceutical effluent. Chemical oxygen demand (COD) and turbidity removals were monitored for each experiment since they are good indicators of wastewater quality. The effects of three parameters such as pH (4-10), current density (i=20-80 mA/cm), and time of reaction (t=10-30 min) were evaluated using a response surface methodology (RSM) and in particular a full factorial central composite face-centered (CCF) design. The obtained experimental data were fit to a second-order polynomial equation using multiple regressions and were also analyzed by variance analysis (ANOVA). The contour plots derived from the mathematical models were applied to determine the optimal conditions (pH of 5.31, current density of 46.83 mA/cm, and electrolysis time of 17.99 min). Under these conditions, the experimental COD and turbidity removals were found equal to 75.64 and 96.34%, respectively, which were in agreement with the values predicted by the models. The electrocoagulation mechanism was modeled using Freundlich and Dubinin-Radushkevich isotherms. The obtained results showed that the Freundlich isotherm correctly predicted the experimental data. Operating costs included energy and electrode consumption as performed for the process of treatment. It was noted that the general cost varied from 0.1053-2.8289 US$ for current densities ranging from 20-80 mA/cm and electrolysis times from 10-30 min. Under optimal conditions, the general cost was found equal to 0.8113 US$/m.
27 citations
Cites background from "Electrochemical Remediation Technol..."
...Brillas and Sires [19] presented an overview on the electrochemical methods devised for the treatment of pharmaceutical residues from both synthetic solutions and real pharmaceutical wastewaters....
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...At pH ≥10, where TC presents as TC and penicillin is in the anionic form, Al (OH)4̄ is dominant and consequently the coagulation rapidly decreases [19, 40-44]....
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TL;DR: The role of the supporting electrolyte in electrochemical oxidation process is crucial since it strongly influence degradation rate, by-products, and acute toxicity.
Abstract: In this work, the effect of supporting electrolytes on the simultaneous electrochemical oxidation of the pharmaceuticals sulfamethoxazole (SMX), propranolol (PRO), and carbamazepine (CBZ) in aqueous solutions has been studied. Based on the identified by-products, the degradation mechanisms were proposed and the acute toxicity was evaluated for each electrolyte. Assays were carried out in batch mode in a 2 L undivided reactor using a niobium coated with boron-doped diamond (Nb/BDD) mesh anode and Ti cathode at 2.5 A in presence of different supporting electrolytes (Na2SO4, NaCl, or NaBr) at the same concentration of 7 mM. The degradation rates were higher in the assays with NaCl and NaBr. Reaction by-products were identified by gas chromatography–mass spectrometry. Indirect oxidation by electrogenerated reactive halogen species (RHS) was the main mechanism when halide ions were used as electrolytes. Ten by-products were detected using Na2SO4 as electrolyte, while 19 (12 non-halogenated and 7 halogenated) and 20 (10 non-halogenated and 10 halogenated) using NaCl and NaBr respectively. The proposed degradation pathways involve transformation (hydroxylation, deamination, desulfonation, and halogenation) and bond rupture to produce less molecular weight compounds and their further transformation until total degradation. Chlorinated and brominated by-products confirm halogenation reactions. The electrogenerated RHS presented a significant inhibition effect on Vibrio fischeri; nevertheless, acute toxicity was not presented using Na2SO4 as electrolyte and a pharmaceutical concentration of 5 μg/L. In this view, the role of the supporting electrolyte in electrochemical oxidation process is crucial since it strongly influence degradation rate, by-products, and acute toxicity.
25 citations
Cites background from "Electrochemical Remediation Technol..."
...89 V for ClO ) (Brillas and Sirés 2012); also, at pH 4, HBrO is the dominant and the most reactive bromide specie....
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...powerful oxidant capable of oxidizing and modifying the structure of organic molecules (Brillas and Sirés 2012)....
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...In addition, at pH 4, the preponderant active chlorine specie is HClO which presents the highest E° among active chlorine species (1.49 V for HClO, 1.36 V for Cl2, and 0.89 V for ClO −) (Brillas and Sirés 2012); also, at pH 4, HBrO is the dominant and the most reactive bromide specie....
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...(12), sulfate ions can be oxidized on Nb/BDD anodes and form persulfate, which is a powerful oxidant capable of oxidizing and modifying the structure of organic molecules (Brillas and Sirés 2012)....
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References
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TL;DR: In this paper, a review of the electrochemical methods used at lab and pilot plant scale to decontaminate synthetic and real effluents containing dyes, considering the period from 2009 to 2013, as an update of our previous review up to 2008.
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3,112 citations
TL;DR: Electro-Fenton (EF) Process 6585 4.2.1.
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