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AOP Processes for Organics Removal in Water and Wastewater

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

Deadline for manuscript submissions: closed (15 January 2022) | Viewed by 35830

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Special Issue Editors

Prof. Dr. Jiangyong Hu

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Guest Editor

Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
Interests: emerging contaminants removal; advanced oxidation process; water treatment and reuse
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Say Leong Ong

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Guest Editor

Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
Interests: water quality enhancement; water reclamation and reuse, biotreatment processes
Special Issues, Collections and Topics in MDPI journals

Dr. Wenjun Sun

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Guest Editor

School of Environment, Tsinghua University, Beijing 100084, China
Interests: UV disinfection; UV advanced oxidation process; advanced treatment process for water and wastewater
Special Issues, Collections and Topics in MDPI journals

Dr. Weiling Sun

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Guest Editor

College of Environmental Science and Engineering, Peking University, Beijing, China
Interests: environmental chemistry; water treatment technology; fate and transformation of PPCPs and EDCs

Special Issue Information

Dear Colleagues,

Water and wastewater contain varying levels of recalcitrant and potentially toxic organic compounds, which necessitates effective treatment prior to final disposal or reuse. At present, advanced oxidation processes (AOP) have gained considerable attention from water professionals due to their ability to rapidly and effectively remove organics and transform them into harmless products.

In view of the above observation, this Special Issue will focus on manuscripts (research papers, reviews, short communications) related to the research and development, policy, implementation, and management of AOP for organics removal in water and wastewater treatment.

Manuscripts in this Special Issue are expected to interpret the results of water quality and cost analysis of AOP process studies within the context of organic pollutant removal and control by evaluating such issues as treatment performance, novel materials and process development, transformation products and pathways, and any other potential impacts in water and wastewater management.

Prof. Dr. Jiangyong Hu
Prof. Dr. Say Leong Ong
Dr. Wenjun Sun
Dr. Weiling Sun
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Advanced oxidation process
Organics removal
Transformation products
Toxicity evaluation
Pre- and post- process
Water and wastewater treatment
Cost-Effectiveness analysis
Policy and management

Published Papers (12 papers)

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Research

Jump to: Review

14 pages, 3501 KiB

Open AccessFeature PaperArticle

Prediction of Second-Order Rate Constants of Sulfate Radical with Aromatic Contaminants Using Quantitative Structure-Activity Relationship Model

by Han Ding and Jiangyong Hu

Water 2022, 14(5), 766; https://doi.org/10.3390/w14050766 - 28 Feb 2022

Cited by 3 | Viewed by 2296

Abstract

Predicting the second-order rate constants between aromatic contaminants and a sulfate radical (

k_{{SO}_{4}^{• -}}

) is vital for the screening of pollutants resistant to sulfate radical-based advanced oxidation processes. In this study, a quantitative structure-activity relationship (QSAR) model was [...] Read more.

Predicting the second-order rate constants between aromatic contaminants and a sulfate radical (

k_{{SO}_{4}^{• -}}

\log k_{{SO}_{4}^{• -}}

and three molecular descriptors (electron density, steric energy, and ratio between oxygen atoms and carbon atoms) was built through multiple linear regression. The goodness-of-fit, robustness, and predictive ability of the model were characterized statistically with indicators showing that the model was reliable and applicable. Electron density was found to be the most influential descriptor that contributed the most to

\log k_{{SO}_{4}^{• -}}

. All data points fell within the applicability domain, and no outliers existed in the training set. The comparison with other models indicates that the QSAR model performs well in elucidating the mechanism of the reaction between aromatic compounds and sulfate radicals. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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10 pages, 1585 KiB

Open AccessArticle

Advance Oxidation Process (AOP) of Bisphenol A Using a Novel Surface-Functionalised Polyacrylonitrile (PAN) Fibre Catalyst

by Jiafan Wang, Jorgelina Farias, Abhishek Tiwary, George Chi Tangyie and Katherine Huddersman

Water 2022, 14(4), 640; https://doi.org/10.3390/w14040640 - 18 Feb 2022

Cited by 2 | Viewed by 1937

Abstract

Bisphenol A (BPA) is a well-known endocrine disruptor in the environment which is not readily oxidised during wastewater treatment at Municipal Authorities. The aim of this work is to evaluate the environmental value of the wastewater treatment of a novel heterogeneous oxidation catalyst by means of the degradation of BPA, avoiding sewage sludge and its post-treatments. A surface-functionalised polyacrylonitrile (PAN) mesh has been produced by reaction of the cyano group of PAN with hydrazine and hydroxylamine salts. This surface-functionalised PAN is then exposed to iron (III) salt solution to promote the ligation of Fe(III) to the functional groups to form the active catalytic site. The experiments were set up in two different batch reactors at laboratory scale at different temperatures and initial pH. The degradation of BPA was detected by measuring the absorbance of BPA in Reverse Phase High Performance Liquid Chromatography at 280 nm. A total elimination of 75 ppm of BPA in less than 30 min was achieved under 300 ppm H₂O₂, 0.5 g PAN catalyst, initial pH 3 and 60 °C. Almost no adsorption of BPA on the catalyst was detected and there was no significant difference in activity of the catalyst after use for two cycles. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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12 pages, 2635 KiB

Open AccessArticle

Oxidation of Aqueous Dexamethasone Solution by Gas-Phase Pulsed Corona Discharge

by Liina Onga, Eneliis Kattel-Salusoo, Marina Trapido and Sergei Preis

Water 2022, 14(3), 467; https://doi.org/10.3390/w14030467 - 04 Feb 2022

Cited by 1 | Viewed by 1701

Abstract

The most widely used anti-inflammatory corticosteroid dexamethasone (DXM), frequently detected in waterbodies due to its massive consumption and incomplete removal in wastewater treatment processes, was experimentally studied for oxidation with gas-phase pulsed corona discharge (PCD) varied in pulse repetition frequency, pH, DXM initial concentration and additions of surfactant sodium dodecyl sulphate (SDS) and tert-butyl alcohol (TBA). The experimental study also included ozonation as compared to PCD in energy efficiency. The advantageous energy efficiency of PCD was observed in wide spans of pH and DXM initial concentrations surpassing ozonation by about 2.4 times. Identified transformation by- and end-products (fluoride and acetate), as well as the impact of radical scavengers, point to the prevalent radical oxidation of DXM. Somewhat increased toxicity observed on the course of PCD-treatment of high DXM concentrations presents a subject for further studies. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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15 pages, 5164 KiB

Open AccessArticle

Degradation of Reactive Brilliant Red X-3B by Photo-Fenton-like Process: Effects of Water Chemistry Factors and Degradation Mechanism

by Gong Cheng, Jing Wan, Qin Li, Lei Sun, Yibo Zhang, Zhang Li, Chenyuan Dang and Jie Fu

Water 2022, 14(3), 380; https://doi.org/10.3390/w14030380 - 27 Jan 2022

Cited by 9 | Viewed by 2535

Abstract

Azo dye wastewater belongs to the highly concentrated organic wastewater, which is difficult to be treated by traditional biological processes. The oxidation efficiency of a single physicochemical method is not considerable. Recent research indicated that the advanced oxidation processes (AOPs) based on the highly reactive hydroxyl radical (∙OH) became one of the preferred methods in dealing with such dye wastewater. In this paper, the typical azo dye, reactive brilliant red X-3B, was employed as the target pollutant, and the transition metal Mn and hydrogen peroxide as the catalysts. A photo-Fenton-like process, UV/Mn²⁺-H₂O₂ system, was established, which enables a combination of various technologies to improve azo dye degradation efficiency while reducing disposal costs. The results indicated that the UV/Mn²⁺-H₂O₂ system had the synergism of Mn²⁺/H₂O₂ and UV/H₂O₂, which was 2.6 times greater than the sum of the two individual effects. And the degradation of X-3B reached the optimum under the conditions of 0.59 mmol/L of the Mn²⁺, 10 mmol/L of the H₂O₂, pH = 6 and a high level of DO. The ∙OH, generated from chem-catalytic and photocatalytic decomposition of H₂O₂, played the predominant role in the decolorization of X-3B and mineralization of its intermediates. The ∙OH tended to attack and break the chromophore group, resulting in the rapid decolorization of X-3B. The azo bond in X-3B was easy to be decomposed in the form of N₂, while the triazinyl group was recalcitrant for ring opening. The degradation process of the UV/Mn²⁺-H₂O₂ system preferred to be conducted at an acidic condition and appropriate concentrations of Mn²⁺ and H₂O₂. The alkaline condition would decrease the utilization of H₂O₂, and excessive H₂O₂ would also quench the ∙OH. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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11 pages, 3394 KiB

Open AccessArticle

Role of Borate Buffer in Organic Degradation by Peroxymonosulfate in the Presence of Metal Oxides

by Saerom Park, Sungjik Oh and Ilho Kim

Water 2021, 13(19), 2698; https://doi.org/10.3390/w13192698 - 29 Sep 2021

Viewed by 2018

Abstract

The effects of borate ions on the reactivity of peroxymonosulfate (PMS) during organic degradation in the presence of metal oxides were examined. The metal oxides exhibited catalytic abilities for the degradation of carbamazepine (CBZ) but not for phenol (PN). Scavenging experiments revealed the absence of radical generation during PN degradation in the presence of the various metal oxides and borate buffer. This indicated that the borate buffer hindered the catalytic abilities of the metal oxides for producing radicals via the PMS oxidant, especially during the faster degradation of compounds such as PN. Various concentrations of borate ions were assessed for enabling pH control and permitting catalytic activity. Fe₂O₃ was found to accelerate and inhibit PN degradation at borate-ion concentrations of 2 mM and 5–20 mM, respectively. Only the 20 mM borate-ion solutions were successful at maintaining the initial pH for 2 d. Phosphate buffer, which was examined as an alternative, also disrupted radical formation but not as considerably as that of the borate ions with metal oxides. This study demonstrates the significance of enabling pH control and permitting the catalytic activity for ensuring the effective use of oxyanions as buffers. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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17 pages, 2625 KiB

Open AccessEditor’s ChoiceArticle

Advanced Oxidation Processes Based on Sulfate Radicals for Wastewater Treatment: Research Trends

by Lizeth Urán-Duque, Julio César Saldarriaga-Molina and Ainhoa Rubio-Clemente

Water 2021, 13(17), 2445; https://doi.org/10.3390/w13172445 - 06 Sep 2021

Cited by 18 | Viewed by 3768

Abstract

In this work, the recent trends in the application of the sulfate radical-based advanced oxidation processes (SR-AOPs) for the treatment of wastewater polluted with emerging contaminants (ECs) and pathogenic load were systematically studied due to the high oxidizing power ascribed to these technologies. Additionally, because of the economic benefits and the synergies presented in terms of efficiency in ECs degradation and pathogen inactivation, the combination of the referred to AOPs and conventional treatments, including biological processes, was covered. Finally, the barriers and limitations related to the implementation of SR-AOPs were described, highlighting the still scarce full-scale implementation and the high operating-costs associated, especially when solar energy cannot be used in the oxidation systems. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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15 pages, 3943 KiB

Open AccessArticle

Degradation of Diclofenac in Urine by Electro-Permanganate Process Driven by Microbial Fuel Cells

by Xuxu Wang, Ying Wang, Jian Zhang, Pengbo Duanmu, Liushi Zheng, Shabi UI Hasson, Andrew Baldwin, Irene Wong and Chun Zhao

Water 2021, 13(15), 2047; https://doi.org/10.3390/w13152047 - 27 Jul 2021

Cited by 9 | Viewed by 2327

Abstract

A novel microbial fuel cell-assisted electro-permanganate process (MFC-PM) was proposed for enhanced diclofenac degradation compared to that of the permanganate oxidation process. By utilizing eco-friendly bio-electricity in situ, the MFC-PM process could activate the simultaneous anodic biological metabolism of urea and the cathodic electro-permanganate process. Density functional analysis and experimental evidence revealed the reactive manganese species (Mn(VII)_aq, Mn(VI)_aq, Mn(V)_aq, and Mn(III)_aq), generated via single electron transfer, contributed to diclofenac degradation in the cathodic chamber. The sites of diclofenac with a high Fukui index were preferable to be attacked by reactive manganese species, and diclofenac degradation was mainly accomplished through the ring hydroxylation, ring opening, and decarboxylation processes. Biological detection revealed clostridia were the primary electron donor in the anode chamber in an anaerobic environment. Furthermore, maximum output power density of 1.49 W m⁻³ and the optimal removal of 94.75% diclofenac were obtained within 20 min under the conditions of pH = 3.0, [DCF]₀ = 60 µM, and [PM]₀ = 30 µM. Diclofenac removal efficiency increased with external resistance, higher PM dosage, and lower catholyte pH. In addition, the MFC-PM process displayed excellent applicability in urine and other background substances. The MFC-PM process provided an efficient and energy-free bio-electricity catalytic permanganate oxidation technology for enhancing diclofenac degradation. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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13 pages, 14233 KiB

Open AccessFeature PaperArticle

Research about Organic Matter Removal and Biofilms Development of Pilot-Scale UV/H₂O₂-BAC Process

by Wuchang Song, Congcong Li, Zhenqi Du, Jiangang Yue, Wenjun Sun, Lian Hou, Jianguang Liu and Ruibao Jia

Water 2021, 13(4), 565; https://doi.org/10.3390/w13040565 - 23 Feb 2021

Cited by 4 | Viewed by 2496

Abstract

As a green advanced process for drinking water treatment, the UV/hydrogen peroxide (UV/H₂O₂) process has been gradually applied in China. To study the effect and mechanism of organic matter removal and the development of microbial communities in the UV/H₂O₂-biological activated carbon (UV/H₂O₂-BAC) process, a pilot-scale UV/H₂O₂-BAC system was built and operated over one year. Low water temperature affects the UV/H₂O₂ process efficiency, the biofilms in the BAC system were mature and stable after 240 days, and the contribution rate of BAC adsorption to dissolved organic carbon (DOC) removal was approximately 14.2% after one year of operation. The liquid chromatography-organic carbon detection (LC-OCD) analysis shows that UV/H₂O₂ process can increase the amounts of Low Molecular Weight (LMW) neutrals, and the specific UV absorbance (SUVA₂₅₄) value is not suitable for predicting Trihalomethanes (THMs) precursor contents in water after UV/H₂O₂ treatment. High-throughput sequencing results prove that microbial species in the middle section are the most abundant compared to those in the influent and effluent sections, hydrogen peroxide has lower inhibition on the development of microbial community than ozone and the low concentration of hydrogen peroxide (<0.25 mg/L) promotes the development of the microbial communities, hydrogen peroxide can reduce Proteobacteria abundance by inhibiting the growth of anaerobes. Acidobacteria may have a certain contribution to the degradation of soil organic matter (SOM), and the effluent section of BAC with low DOC concentration cannot form the dominant species of Rhodobacter. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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17 pages, 2845 KiB

Open AccessArticle

Treatment of Bio-Treated Coking Wastewater by Catalytic Ozonation with Semi-Batch and Continuous Flow Reactors

by Can He, Jianbing Wang, Heng Xu, Xiangyu Ji, Weiyi Wang and Xieyang Xu

Water 2020, 12(9), 2532; https://doi.org/10.3390/w12092532 - 10 Sep 2020

Cited by 2 | Viewed by 2402

Abstract

In this work, the treatment of bio-treated coking wastewater (BCW) by catalytic ozonation was conducted in semi-batch and continuous flow reactors. The kinetics of chemical oxygen demand (COD) removal were analyzed using BCWs from five coking plants. An integral reactor with catalytic ozonation stacked by ozone absorption (IR) was developed, and its efficiency was studied. The catalyst of Mn_xCe_1-xO₂/γ-Al₂O₃ was efficient in the catalytic ozonation process for the treatment of various BCWs. The chemical oxygen demand (COD) removal efficiencies after 120 min reaction were 64–74%. The overall apparent reaction rate constants were 0.0101–0.0117 min⁻¹, which has no obvious relationship with the initial COD of BCW and pre-treatment biological process. The IR demonstrated the highest efficiency due to the enhancement of mass transfer and the utilization efficiency of ozone. Bypass internal circulation can further improve the reactor efficiency. The optimal results were obtained with the ozone absorption section accounting for 19% of the valid water depth in the reactor and 250% of circulation flow ratio. The long-term and full-scale application of the novel reactor in a continuous mode indicated stable removal of COD and polycyclic aromatic hydrocarbons (PAHs). The results showed that the system of IR is a promising reactor type for tertiary treatment of coking wastewater by catalytic ozonation. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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12 pages, 3592 KiB

Open AccessFeature PaperArticle

Removal of 17β-Estradiol by Activated Charcoal Supported Titanate Nanotubes (TNTs@AC) through Initial Adsorption and Subsequent Photo-Degradation: Intermediates, DFT calculation, and Mechanisms

by Taobo Huang, Baozhu Pan, Haodong Ji and Wen Liu

Water 2020, 12(8), 2121; https://doi.org/10.3390/w12082121 - 26 Jul 2020

Cited by 7 | Viewed by 3105

Abstract

A low-cost composite of activated charcoal supported titanate nanotubes (TNTs@AC) was developed via the facile hydrothermal method to remove the 17β-estradiol (E2, a model of pharmaceutical and personal care products) in water matrix by initial adsorption and subsequent photo-degradation. Characterizations indicated that the modification occurred, i.e., the titanate nanotubes would be grafted onto the activated charcoal (AC) surface, and the micro-carbon could modify the tubular structure of TNTs. E2 was rapidly adsorbed onto TNTs@AC, and the uptake reached 1.87 mg/g from the dual-mode model fitting. Subsequently, the adsorbed E2 could be degraded 99.8% within 2 h under ultraviolet (UV) light irradiation. TNTs@AC was attributed with a unique hybrid structure, providing the hydrophobic effect, π−π interaction, and capillary condensation for E2 adsorption, and facilitating the electron transfer and then enhancing photocatalytic ability for E2-degradation. In addition, the removal mechanism of E2 was elucidated through the density functional theory calculation. Our study is expected to provide a promising material for environmental application. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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10 pages, 2455 KiB

Open AccessFeature PaperArticle

Photolytic Degradation of Tetracycline in the Presence of Ca(II) and/or Humic Acid

by Si Li, Yiyan He, Fanguang Kong, Weiling Sun and Jiangyong Hu

Water 2020, 12(8), 2078; https://doi.org/10.3390/w12082078 - 22 Jul 2020

Cited by 8 | Viewed by 2874

Abstract

Photolytic degradation of tetracycline (TC) was investigated in mono- and binary solute systems of Ca(II) and humic acid (HA) under UVA light emitting diode (UVA-LED) light irradiation. TC photolysis proceeded via pseudo-first-order reaction kinetics. The presence of Ca(II) significantly accelerated the degradation rate constants of TC, with the highest value at 0.0314 ± 0.0019 min⁻¹ when the Ca(II) concentration was 5.0 mM. The promoted degradation was attributed to complexation of TC with Ca(II), which increased the light absorption. Absorbance and fluorescence measurements revealed that the strong complexation between TC and Ca(II) likely occurred via the C11 and C12 oxygen groups in the phenolic-diketone moiety of TC in nearly neutral solutions. The formation of HA-Ca(II) complex was found in the binary solute system of HA and Ca(II). Thus, the promotional effect of Ca(II) on photolysis was diminished by HA addition. The largest reduction of 32.5% in rate constants was observed with the highest Ca(II) concentration. Scavenger studies revealed that TC could undergo direct photolysis and self-sensitization by ¹O₂. These results suggest that the coexistence of HA and Ca(II) greatly influences the fate of TC in natural waters, which has important implications for understanding the behavior of antibiotics coexisting with other metal species and ligands. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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Review

Jump to: Research

38 pages, 1907 KiB

Open AccessFeature PaperReview

Emerging Contaminants: An Overview of Recent Trends for Their Treatment and Management Using Light-Driven Processes

by Brandon Chuan Yee Lee, Fang Yee Lim, Wei Hao Loh, Say Leong Ong and Jiangyong Hu

Water 2021, 13(17), 2340; https://doi.org/10.3390/w13172340 - 26 Aug 2021

Cited by 18 | Viewed by 6443

Abstract

The management of contaminants of emerging concern (CECs) in water bodies is particularly challenging due to the difficulty in detection and their recalcitrant degradation by conventional means. In this review, CECs are characterized to give insights into the potential degradation performance of similar compounds. A two-pronged approach was then proposed for the overall management of CECs. Light-driven oxidation processes, namely photo/Fenton, photocatalysis, photolysis, UV/Ozone were discussed. Advances to overcome current limitations in these light-driven processes were proposed, focusing on recent trends and innovations. Light-based detection methodology was also discussed for the management of CECs. Lastly, a cost–benefit analysis on various light-based processes was conducted to access the suitability for CECs degradation. It was found that the UV/Ozone process might not be suitable due to the complication with pH adjustments and limited light wavelength. It was found that E_EO values were in this sequence: UV only > UV/combination > photocatalyst > UV/O₃ > UV/Fenton > solar/Fenton. The solar/Fenton process has the least computed E_EO < 5 kWh m⁻³ and great potential for further development. Newer innovations such as solar/catalyst can also be explored with potentially lower E_EO values. Full article

(This article belongs to the Special Issue AOP Processes for Organics Removal in Water and Wastewater)

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