Special Issue "Wastewater Engineering and Environmental Catalysis"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Wastewater Treatment and Reuse".

Deadline for manuscript submissions: closed (31 December 2020).

Special Issue Editor

Dr. Zacharias Frontistis
E-Mail Website
Guest Editor

Special Issue Information

Dear Colleagues,

In recent years, the use of physicochemical methods, such as advanced oxidation processes (AOPs), for the treatment of waste water has consistently been gaining ground. These processes are based on the in situ production of very reactive oxygen species (mainly, but not exclusively, hydroxyl radicals, including technologies such as semiconductor photocatalysis, photon Fenton and Fenton like processes, ozonation, wet air oxidation, sonochemistry, electrochemical oxidation, gamma ray, etc.). At the same time, research into hybrid processes has been steadily growing over the past few years, involving more than one process, resulting in synergy effects, leading to a higher efficiency, which will lead to the implementation of these processes on a large scale. Under this perspective, this Special Issue of Water welcomes the application of various advanced oxidation processes for the treatment of highly resistant compounds, as well as for disinfection. Articles dealing with the application of new catalytic materials for environmental protection, as well as the experimental and modeling of pilot plants and hybrid processes, are particularly welcome.

Prof. Dr. Zacharias Frontistis
Guest Editor

Manuscript Submission Information

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Keywords

  • advanced oxidation processes
  • hybrid processes
  • disinfection
  • micropollutants
  • environmental catalysis
  • photocatalysis
  • radicals
  • pharmaceuticals
  • industrial wastewaters
  • pilot plant

Published Papers (10 papers)

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Editorial

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Editorial
New Trends in Environmental Catalytic Technologies for Water Remediation
Water 2021, 13(4), 571; https://0-doi-org.brum.beds.ac.uk/10.3390/w13040571 - 23 Feb 2021
Viewed by 524
Abstract
Due to climate change, industrialization, and overpopulation, water resources management is becoming a crucial sector [...] Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)

Research

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Article
Removal of Polycyclic Aromatic Hydrocarbons in a Heterogeneous Fenton Like Oxidation System Using Nanoscale Zero-Valent Iron as a Catalyst
Water 2020, 12(9), 2430; https://0-doi-org.brum.beds.ac.uk/10.3390/w12092430 - 29 Aug 2020
Cited by 4 | Viewed by 1153
Abstract
Oil and gas effluents contains highly toxic and harmful organic pollutants. Therefore, it is necessary to eliminate and/or reduced the concertation of organic pollutants to a technologically acceptable levels before their discharge into water streams. This study investigates the application of nanoscale zero-valent [...] Read more.
Oil and gas effluents contains highly toxic and harmful organic pollutants. Therefore, it is necessary to eliminate and/or reduced the concertation of organic pollutants to a technologically acceptable levels before their discharge into water streams. This study investigates the application of nanoscale zero-valent iron (nZVI), and hydrogen peroxide (H2O2) for removal of organic pollutants from real oily produced water. Batch studies were performed and effect of different operating parameters, including concentration of nZVI and H2O2, pH and reaction time were studied. Moreover, optimization of independent variables was performed using central composite design (CCD) in response surface methodology (RSM). The experimental set up provided maximum removal efficiencies of 89.5% and 75.3% for polycyclic aromatic hydrocarbons (PAHs) and chemical oxygen demand (COD), respectively. The optimum values of independent variables such as concentrations of nZVI, and H2O2, contact time and pH were obtained as 4.35 g/L, 1.60 g/L, 199.9 min and 2.9, respectively. Predicted PAHs and COD removal efficiencies at the optimum values of independent variables were found as 89.3% and 75.7%, respectively which are in line with the experimental values. The study indicates that application of heterogeneous Fenton like oxidation system using nZVI as a catalyst is an efficient treatment method for removal of organic pollutants from real produced water. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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Article
The Improvement Effects of Different Treatment Methods of Soil Wastewater Washing on Environmental Pollution
Water 2020, 12(9), 2329; https://0-doi-org.brum.beds.ac.uk/10.3390/w12092329 - 19 Aug 2020
Cited by 3 | Viewed by 570
Abstract
This paper focus on how to treat the wastewater after soil washing since water pollution is a severe threat to the water security of China. Ca (OH)2 and two kinds of biochars (biochar and ZnCl2 modified biochar) were tested to treat [...] Read more.
This paper focus on how to treat the wastewater after soil washing since water pollution is a severe threat to the water security of China. Ca (OH)2 and two kinds of biochars (biochar and ZnCl2 modified biochar) were tested to treat the waste FeCl3 washing effluent. Two kinds of biochars (biochar and ZnCl2-modified biochar) were prepared from maize straws. Soil samples were collected near a smelter for adsorption experiments. ICP-OES was used to determine the concentration of metal ions in the samples, as well as calculating their adsorption capacity and removal rate. As to Ca(OH)2 treatment, the maximum removal rates of Cd, Pb, Cu, and Zn could exceed 99%, and the concentrations of Cd, Pb, Cu, and Zn in solution could reduce to 0.08, 0.018, 0.15, 0.44 mg/dm3, respectively. However, both of the two biochars had relatively low removal rates compared with Ca (OH)2 treatment. The wastewater shows significantly lower environmental implications after the two treatments, and the lime precipitation method has better effects than biochar adsorption. The activated carbon adsorption method discussed can significantly improve the environmental pollution caused by soil washing wastewater, which is suitable for environmental treatment projects. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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Article
Electro-Oxidation of Humic Acids Using Platinum Electrodes: An Experimental Approach and Kinetic Modelling
Water 2020, 12(8), 2250; https://0-doi-org.brum.beds.ac.uk/10.3390/w12082250 - 10 Aug 2020
Cited by 6 | Viewed by 819
Abstract
Humic acids (HA) are a potential hazard to aquatic ecosystems and human health. Because biological treatment of contaminated water does not satisfactorily remove these pollutants, novel approaches are under evaluation. This work explores electrochemical oxidation of HA in aqueous solution in a lab-scale [...] Read more.
Humic acids (HA) are a potential hazard to aquatic ecosystems and human health. Because biological treatment of contaminated water does not satisfactorily remove these pollutants, novel approaches are under evaluation. This work explores electrochemical oxidation of HA in aqueous solution in a lab-scale apparatus using platinum-coated titanium electrodes. We evaluated the effects of HA concentration, current density, chloride concentration and ionic strength on the rate of HA oxidation. The initial reaction rate method was used for determining the rate law of HA degradation. The results showed that the reaction rate was first-order relative to HA concentration, chloride concentration and current density. An appreciable effect of ionic strength was also observed, most likely due to the polyanionic character of HA. We propose a kinetic model that satisfactorily fits the experimental data. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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Article
Sulfamethoxazole and Trimethoprim Degradation by Fenton and Fenton-Like Processes
Water 2020, 12(6), 1655; https://0-doi-org.brum.beds.ac.uk/10.3390/w12061655 - 09 Jun 2020
Cited by 6 | Viewed by 978
Abstract
In this work, the degradation of sulfamethoxazole (SMX) and trimethoprim (TMP) via Fenton and Fenton-like processes was evaluated using Mn2+ as supporting catalyst in the Fenton reaction. The optimum conditions of degradation were also evaluated. Besides that, the effect of independent factors [...] Read more.
In this work, the degradation of sulfamethoxazole (SMX) and trimethoprim (TMP) via Fenton and Fenton-like processes was evaluated using Mn2+ as supporting catalyst in the Fenton reaction. The optimum conditions of degradation were also evaluated. Besides that, the effect of independent factors pH, [H2O2], [Fe2+], [Mn2+] and reaction time (t) on the efficiency of the SMX and TMP degradation were assessed. Box–Behnken was the experimental design adopted, delineating the relative concentration (C/Co) of antibiotics after treatments as response variable. The inferences were conducted using variance analysis, Pareto chart, response surface methodology, and desirability function. Due to the lack of adjustment of the SMX degradation model, there are no more inferences about it. The significant variables (p ≤ 0.05) on TMP degradation were: reaction time quadratic and linear effect, [Fe2+] linear effect, [Mn2+] linear effect, interaction pH vs. [Mn2+]. The Mn2+ addition aided TMP degradation in environments with lower pH values. However, the addition may harm the efficiency of the antibiotic degradation at higher pH. The optimum condition for TMP degradation in the conventional process (without the addition of Mn2+) is: pH 5, [H2O2] equal to 4.41 mmol L−1, [Fe2+] equal to 0.81 mmol L−1 and 90 min reaction time. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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Article
Coupling Persulfate-Based AOPs: A Novel Approach for Piroxicam Degradation in Aqueous Matrices
Water 2020, 12(6), 1530; https://0-doi-org.brum.beds.ac.uk/10.3390/w12061530 - 27 May 2020
Cited by 6 | Viewed by 907
Abstract
The activated persulfate degradation of piroxicam, a non-steroidal anti-inflammatory drug (NSAID) belonging to oxicams, was investigated. Persulfate was activated with thermal energy or (UV-A and simulated solar) irradiation. Using 250 mg/L sodium persulfate at 40 °C degraded almost completely 0.5 mg/L of piroxicam [...] Read more.
The activated persulfate degradation of piroxicam, a non-steroidal anti-inflammatory drug (NSAID) belonging to oxicams, was investigated. Persulfate was activated with thermal energy or (UV-A and simulated solar) irradiation. Using 250 mg/L sodium persulfate at 40 °C degraded almost completely 0.5 mg/L of piroxicam in 30 min. Increasing piroxicam concentration from 0.5 to 4.5 mg/L decreased its removal. The observed kinetic constant was increased almost ten times from 0.077 to 0.755 min−1, when the temperature was increased from 40 to 60 °C, respectively. Process efficiency was enhanced at pH 5–7. At ambient conditions and 30 min of irradiation, 94.1% and 89.8% of 0.5 mg/L piroxicam was removed using UV-A LED or simulated solar radiation, respectively. Interestingly, the use of simulated sunlight was advantageous over UV-A light for both secondary effluent, and 20 mg/L of humic acid solution. Unlike other advanced oxidation processes, the presence of bicarbonate or chloride in the range 50–250 mg/L enhanced the degradation rate, while the presence of humic acid delayed the removal of piroxicam. The use of 0.5 and 10 g/L of methanol or tert-butanol as radical scavengers inhibited the reaction. The coupling of thermal and light activation methods in different aqueous matrices showed a high level of synergy. The synergy factor was calculated as 68.4% and 58.4% for thermal activation (40 °C) coupled with either solar light in 20 mg/L of humic acid or UV-A LED light in secondary effluent, respectively. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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Article
Photocatalytic Evaluation of Ag2CO3 for Ethylparaben Degradation in Different Water Matrices
Water 2020, 12(4), 1180; https://0-doi-org.brum.beds.ac.uk/10.3390/w12041180 - 20 Apr 2020
Cited by 7 | Viewed by 1092
Abstract
The present study examines the photocatalytic properties of silver carbonate (Ag2CO3) for ethyl paraben (EP) degradation under simulated solar irradiation. Ag2CO3 was prepared according to a solution method and its physicochemical characteristics were studied by means [...] Read more.
The present study examines the photocatalytic properties of silver carbonate (Ag2CO3) for ethyl paraben (EP) degradation under simulated solar irradiation. Ag2CO3 was prepared according to a solution method and its physicochemical characteristics were studied by means of X-ray diffraction (XRD), the Brunauer–Emmett–Teller (BET) method, diffuse reflectance spectroscopy (DRS), and transmission electron microscopy (TEM). Complete EP (0.5 mg/L) removal was achieved after 120 min of irradiation with the use of 750 mg/L Ag2CO3 in ultrapure water (UPW), with EP degradation following pseudo-first-order kinetics. The effect of several experimental parameters was investigated; increasing catalyst concentration from 250 mg/L to 1000 mg/L led to an increase in EP removal, while increasing EP concentration from 0.25 mg/L to 1.00 mg/L slightly lowered kapp from 0.115 min−1 to 0.085 min−1. Experiments carried out with the use of UV or visible cut-off filters showed sufficient EP degradation under visible irradiation. A series of experiments were performed in real water matrices such as bottled water (BW) and wastewater (WW), manifesting Ag2CO3’s equally high photocatalytic activity for EP degradation. To interpret these results different concentrations of inorganic anions (bicarbonate 100–500 mg/L, chloride 100–500 mg/L) present in aqueous media, as well as 10 mg/L organic matter in the form of humic acid (HA), were added sequentially in UPW. Results showed accelerating effects on EP degradation for the lowest concentrations tested in all cases. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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Article
Eggshell-supported Catalysts for the Advanced Oxidation Treatment of Humic Acid Polluted Wastewaters
Water 2020, 12(1), 100; https://0-doi-org.brum.beds.ac.uk/10.3390/w12010100 - 27 Dec 2019
Cited by 3 | Viewed by 1526
Abstract
Metal nanoparticles have been reported as effective catalysts for the removal of refractory compounds from industrial wastewaters in advanced oxidation processes. Additionally, hundreds of thousands of tons of eggshells are discarded worldwide each year. In this work, this waste has been evaluated as [...] Read more.
Metal nanoparticles have been reported as effective catalysts for the removal of refractory compounds from industrial wastewaters in advanced oxidation processes. Additionally, hundreds of thousands of tons of eggshells are discarded worldwide each year. In this work, this waste has been evaluated as support for the synthesis of nanomaterials by wet impregnation method. Four supported catalysts, with a load of iron or copper of 5% and 15%, were prepared and thoroughly characterized by means of different techniques (elemental analysis, XRF, XRD, FTIR, N2 adsorption-desorption, SEM, TEM and TGA). The catalysts performance was evaluated in wet oxidation tests to degrade humic acids, analyzing the evolution with time of COD, biodegradability index (BOD5/COD), color number and pH. The best results were achieved with 15% Cu and 5% Fe catalysts (COD reduction being 82.3% and 75.1%, respectively), whereas a COD reduction of 58% was obtained employing non-impregnated eggshell. This can be mainly attributed to the metal loading and the good metal distribution on the surface of the support. The BOD5 value of humic acids was initially null and, in all assays, the oxidation treatment enhanced the biodegradability. Therefore, eggshell has proved to be an interesting material to be employed as support in nanoparticles preparation. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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Article
Photocatalytic Treatment of Pharmaceuticals in Real Hospital Wastewaters for Effluent Quality Amelioration
Water 2019, 11(10), 2165; https://0-doi-org.brum.beds.ac.uk/10.3390/w11102165 - 17 Oct 2019
Cited by 12 | Viewed by 1304
Abstract
The presence of pharmaceutically active compounds (PhACs) in the wastewater effluents has confirmed that conventional wastewater treatment technologies are not sufficiently effective in the pharmaceuticals’ removal. The objective of the present study was to evaluate and compare the photocatalytic degradation of PhACs using [...] Read more.
The presence of pharmaceutically active compounds (PhACs) in the wastewater effluents has confirmed that conventional wastewater treatment technologies are not sufficiently effective in the pharmaceuticals’ removal. The objective of the present study was to evaluate and compare the photocatalytic degradation of PhACs using TiO2-P25, graphitic carbon nitride (g-C3N4, CN) and a heterojunction of perovskite strodium titanate and graphitic carbon nitride SrTiO3/g-C3N4 (20% g-C3N4, 20CNSTO) photocatalytic materials, in hospital wastewater effluents, by simulated solar irradiation. The experiments were performed by using real wastewater samples collected from the university hospital wastewater treatment plant (WWTP) effluent of Ioannina city (Northwestern Greece) and inherent pharmaceutical concentration levels. The analysis of the samples was accomplished by solid phase extraction followed by liquid chromatography-Orbitrap high-resolution mass spectrometry. In the cases of TiO2 and CN, more than 70% of the initial concentration (e.g., venlafaxine) was degraded after 90 min, while 20CNSTO presented lower photocatalytic performance. Furthermore, some compounds were sporadically detected (e.g., fluoxetine) or their concentrations remained stable during the photocatalytic treatment time period (e.g., trimethoprim). In total 11 transformation products (TPs) were formed along the degradation processes and were identified by using liquid chromatography high resolution mass spectrometry. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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Article
Enhanced Photo-Catalytic Performance of Activated Carbon Fibers for Water Treatment
Water 2019, 11(9), 1794; https://0-doi-org.brum.beds.ac.uk/10.3390/w11091794 - 29 Aug 2019
Cited by 5 | Viewed by 1211
Abstract
The synthesis, characterization, and performance of composite photocatalytic adsorbents are investigated in this work using the dip-coating and the electrophoretic coating methods for the deposition of titanium dioxide (TiO2) on porous activated carbon fiber (ACF) substrates. The adsorption and photocatalytic efficiency [...] Read more.
The synthesis, characterization, and performance of composite photocatalytic adsorbents are investigated in this work using the dip-coating and the electrophoretic coating methods for the deposition of titanium dioxide (TiO2) on porous activated carbon fiber (ACF) substrates. The adsorption and photocatalytic efficiency of the synthesized catalytic adsorbents were compared using phenol as the model pollutant. Both immobilization techniques resulted in composite ACF/TiO2 adsorbents characterized by large surface area (844.67 ± 45.58 m2 g−1), uniform distribution of TiO2 nanoparticles on the activated carbon fibers, and high phenol adsorption. The method and the treatment time affected the phenol adsorption, while the highest sorption was determined in the case of the ACF/TiO2 sample prepared by the electrophoretic coating method (at 20 V) for an electrolysis time of 120 s (7.93 mgphenol g−1ACF/TiO2). The UV-A irradiation of most ACF/TiO2 samples led to a faster removal of phenol from water as a result of the combined sorption and heterogeneous photocatalysis. The stability and the effective regeneration of the most promising composite photocatalytic adsorbent was proved by multiple filtration and UV-A irradiation cycles. Full article
(This article belongs to the Special Issue Wastewater Engineering and Environmental Catalysis)
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