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12 pages, 3159 KiB

Open AccessArticle

Efficiency of Orange Yellow II Degradation by Synergistic Hydroxylamine with Fe²⁺ to Activate Peroxymonosulfate Oxidation: Machine Learning Prediction and Performance Optimization

by Runjuan Zhou, Kuo Zhang and Ming Zhang

Water 2023, 15(10), 1931; https://doi.org/10.3390/w15101931 - 19 May 2023

Cited by 1 | Viewed by 1628

Abstract

A back-propagation neural network (BPNN) was used to model and optimize the process of hydroxylamine (HA)-enhanced Fe²⁺ activating peroxymonosulfate (PMS). Using HA-enhanced Fe²⁺ to activate PMS is a cost-effective method to degrade orange II (AO7). We investigated the individual and interactive [...] Read more.

A back-propagation neural network (BPNN) was used to model and optimize the process of hydroxylamine (HA)-enhanced Fe²⁺ activating peroxymonosulfate (PMS). Using HA-enhanced Fe²⁺ to activate PMS is a cost-effective method to degrade orange II (AO7). We investigated the individual and interactive effects of the concentrations of Fe²⁺, HA, and PMS on the degradation of AO7. The R² of the BPNN model was 0.99852, and the data were distributed around y = x. Sensitivity analysis showed that the relative importance of each factor was as follows: HA > Fe²⁺ > PMS. The optimized results obtained by the genetic algorithm were as follows: the concentration of Fe²⁺ was 35.33 μmol·L⁻¹, HA was 0.46 mmol·L⁻¹, and PMS was 0.93 mmol·L⁻¹. Experiments verified that the AO7 degradation effect within 5 min was 95.7%, whereas the predicted value by the BPNN was 96.2%. The difference between predicted and experimental values is 0.5%. This study provides a new tool (machine learning) to accurately predict the concentrations of HA, Fe²⁺, and PMS to degrade AO7 under various conditions. Full article

(This article belongs to the Special Issue Advanced Oxidation/Reduction and Biological Processes for Water and Wastewater)

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21 pages, 7505 KiB

Open AccessArticle

Photocatalytic Removal of Ciprofloxacin in Water by Novel Sandwich-like CuFe₂O₄ on rGO/Halloysite Material: Insights into Kinetics and Intermediate Reactive Radicals

by Ha-Son Ngo, Thi-Linh Nguyen, Ngoc-Tuan Tran and Hanh-Chi Le

Water 2023, 15(8), 1569; https://doi.org/10.3390/w15081569 - 17 Apr 2023

Cited by 7 | Viewed by 2279

Abstract

In this study, the CuFe₂O₄ on rGO/halloysite material was made in an uncomplicated manner. The catalyst has a sandwich-like shape with a uniform coating of the active phase on the rGO sheets and halloysite tubes. The catalyst’s large specific surface [...] Read more.

In this study, the CuFe₂O₄ on rGO/halloysite material was made in an uncomplicated manner. The catalyst has a sandwich-like shape with a uniform coating of the active phase on the rGO sheets and halloysite tubes. The catalyst’s large specific surface area (130 m²/g) and small band gap energy (1.9 eV) allow it to adsorb photons and photocatalyze organic contaminants effectively. In approximately 1 h of light, the catalyst showed high performance in achieving almost complete conversion in photodegrading CIP for an initial CIP concentration of 20 ppm. A pseudo-first-order rate law was followed by the process, as revealed by the experimental results. In addition, the pH effect and the contribution of intermediate reactive radicals that emerged during the photochemical process were explored. The results indicated that hydroxyl radicals and holes had a major impact on CIP decomposition, suggesting that the addition of these radicals could enhance CIP degradation efficiency at a larger scale. This study also confirmed the superiority of catalysis and photochemical processes in environmental treatments by the neutral pH values. Full article

(This article belongs to the Special Issue Advanced Oxidation/Reduction and Biological Processes for Water and Wastewater)

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21 pages, 2392 KiB

Open AccessArticle

Application of Advanced Oxidation Processes for the Treatment of Color and Chemical Oxygen Demand of Pulp and Paper Wastewater

by Tariq Javeed, Rab Nawaz, Sami A. Al-Hussain, Ali Irfan, Muhammad Atif Irshad, Sajjad Ahmad and Magdi E. A. Zaki

Water 2023, 15(7), 1347; https://doi.org/10.3390/w15071347 - 31 Mar 2023

Cited by 8 | Viewed by 3843

Abstract

The present study was conducted in order to investigate the efficiency of different advanced oxidation processes both individually and in combination with the biological method for the removal of color and chemical oxygen demand (COD) from wastewater in the pulp and paper industry. [...] Read more.

The present study was conducted in order to investigate the efficiency of different advanced oxidation processes both individually and in combination with the biological method for the removal of color and chemical oxygen demand (COD) from wastewater in the pulp and paper industry. Advanced oxidation processes include ozone, Fenton, hydrogen peroxide, and photo-Fenton. Biologically treated wastewater was successively subjected to advanced oxidation processes (AOPs). The optimum conditions for the ozone treatment of raw wastewater were found to be a contact time of 9 min and a pH of 5 at a fixed dose of ozone for a removal efficiency of 41.22% for color and 88.53% for COD. Similar optimum conditions for the ozone treatment of biologically treated wastewater showed a removal efficiency of 46.36% for color and 95.92% for COD. The photo-Fenton process also showed an efficiency comparable to the ozone treatment for both raw wastewater and biologically treated wastewater, resulting in a removal efficiency of 39.85% (color) and 90.13% (COD) for raw wastewater, and of 41.34% (color) and 94.29% (COD) for biologically treated wastewater. Each had a contact time of 12 h. The Fenton oxidation of raw wastewater showed a removal efficiency of more than 26.30% for color and 86.33% for COD. Fenton oxidation, however, showed an efficiency of 26.62% for color and 84.49% for COD removal from biologically treated wastewater. Hydrogen peroxide showed an efficiency of 28.45% for color and 85.13% for COD removal from raw wastewater, and 39.48% for color and 86.53% for COD removal from biologically treated wastewater. The results for the raw wastewater treatments indicated that higher removal efficiencies can be achieved when they are used as pre-treatments. Biological treatment is a cost-effective method but it has less efficiency for color removal. In combination with one of the AOPs, either as a pre- or post-treatment under a controlled time and dose, biological treatment increased the efficiency, making treatment feasible at larger scales. Full article

(This article belongs to the Special Issue Advanced Oxidation/Reduction and Biological Processes for Water and Wastewater)

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13 pages, 2026 KiB

Open AccessArticle

Influence of Sediment Dredging on the Distribution of Chlorinated Paraffin

by Tao Yang, Bangping Deng and Chenyong Miao

Water 2022, 14(21), 3461; https://doi.org/10.3390/w14213461 - 29 Oct 2022

Viewed by 1907

Abstract

To study the influence of dredged sediment transportation on the distribution of short-chain chlorinated paraffins (SCCPs, C10-13), medium-chain chlorinated paraffins (MCCPs, C13-17), and long-chain chlorinated paraffins (LCCPs, C18-28), 62 surficial sediment samples were collected from the Huangpu River and the Shanghai offshore areas, [...] Read more.

To study the influence of dredged sediment transportation on the distribution of short-chain chlorinated paraffins (SCCPs, C10-13), medium-chain chlorinated paraffins (MCCPs, C13-17), and long-chain chlorinated paraffins (LCCPs, C18-28), 62 surficial sediment samples were collected from the Huangpu River and the Shanghai offshore areas, East China. A high-performance liquid chromatograph coupled with a quadrupole time-of-flight mass spectrometry system (HPLC-QTOF MS) was employed to measure CPs. The concentrations of CPs in sediment samples ranged from 8.76 to 1270.7 ng g⁻¹ for SCCPs, from 22.03 to 1730.78 ng g⁻¹ for MCCPs, and from undetected (ND) to 236.86 ng g⁻¹ for LCCPs. The concentrations were lower than those that can be toxic to organisms. Furthermore, the influence of sediment dredging activity on the distribution of CPs was also investigated. The concentrations of CPs in sediment discarding areas were significantly higher than those in the surrounding areas, but this result is consistent with the concentrations in the Huangpu River sediments where CPs originated. Also, the SCCP congener group in the discarding area was similar to that in the Huangpu River. These findings indicated that CPs exhibited lower migration in the discarding area and had limited environmental impacts. Full article

(This article belongs to the Special Issue Advanced Oxidation/Reduction and Biological Processes for Water and Wastewater)

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16 pages, 3381 KiB

Open AccessArticle

Assessment of Glucocorticoid Removal by UVA/Chlorination and Ozonation: Performance Comparison in Kinetics, Degradation Pathway, and Toxicity

by Ai Zhang, Xinyuan Jiang, Qiancheng Wang, Siyu Hao, Dahai Zhu, Jie Wang, Ce Wang and Mingyan Liu

Water 2022, 14(16), 2493; https://doi.org/10.3390/w14162493 - 13 Aug 2022

Cited by 1 | Viewed by 2160

Abstract

Glucocorticoids (GCs) have drawn great concern due to widespread contamination in the environment and application in treating COVID-19. This work aimed to compare the performance of UVA/chlorination and ozonation on GC removal in terms of removal efficiency, degradation pathway, and toxicity change, with [...] Read more.

Glucocorticoids (GCs) have drawn great concern due to widespread contamination in the environment and application in treating COVID-19. This work aimed to compare the performance of UVA/chlorination and ozonation on GC removal in terms of removal efficiency, degradation pathway, and toxicity change, with fluocinolone acetonide (FA), triamcinolone acetonide (TA), and clobetasol propionate (CP) as target compounds. The results showed that both UVA/chlorination and ozonation could degrade GCs. Compared with UVA/chlorination (removal efficiency of 89% for FA, 86% for TA, and 90% for CP at 7 h), ozonation (removal efficiency of 90% for FA, 96% for TA, and 98% for CP at 15 min) was more effective in GC removal. Photodegradation contributed most to GC removal during UVA/chlorination, while O₃ molecules were the main functional species during ozonation. H-abstraction, dechlorination, carbon–carbon bond cleavage, and ester hydrolysis were proposed for both UVA/chlorination and ozonation based on the identification of intermediates. However, ozone tended to attack C=C double bonds, resulting in the cracked benzene ring of GCs, while chlorine was more likely to attack alcohol and ketone groups. Although most GCs were removed during ozonation and UVA/chlorination, their acute toxicities slightly declined. Compared with UVA/chlorination, ozonation was more effective in toxicity reduction. Full article

(This article belongs to the Special Issue Advanced Oxidation/Reduction and Biological Processes for Water and Wastewater)

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10 pages, 2625 KiB

Open AccessArticle

Removal of Trichloroethylene from Water by Bimetallic Ni/Fe Nanoparticles

by Xiaonan Liu, Minghong Wu and Jian Zhao

Water 2022, 14(10), 1616; https://doi.org/10.3390/w14101616 - 18 May 2022

Cited by 10 | Viewed by 2378

Abstract

Chlorinated organic solvents (COSs) are a significant threat to human beings. In this study, nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride (NaBH₄) with the reduction of Ni²⁺ and Fe²⁺ in an aqueous solution. The [...] Read more.

Chlorinated organic solvents (COSs) are a significant threat to human beings. In this study, nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride (NaBH₄) with the reduction of Ni²⁺ and Fe²⁺ in an aqueous solution. The synthesized nanoscale zero-valent iron (nZVI) and Ni-nZVI were characterized by SEM (scanning electron microscopy), XRD (X-ray diffractometer), Brunauer–Emmett–Teller (BET), and transmission electron microscopy (TEM). The removal performance of trichloroethylene (TCE) over the nZVI catalyst and Ni-nZVI was evaluated. Ni-nZVI with different Ni contents exhibited good reactivity towards the dechlorination of TCE over a 1h period, and the pseudo-first-order rate constant for TCE dechlorination by Ni-nZVI was 1.4–3.5 times higher than that of nZVI. Ni-nZVI with 5 wt% Ni contents exhibited the best dechlorination effect; the removal rates of TCE and its by-product dichloroethylene (DCE) were 100% and 63.69%, respectively. These results indicated that the Ni nanoparticles as the second dopant metal were better than nZVI for TCE degradation. This determination of the optimal Ni-NZVI load ratio provides a factual and theoretical basis for the subsequent application of nano-metal binding in the environment. Full article

(This article belongs to the Special Issue Advanced Oxidation/Reduction and Biological Processes for Water and Wastewater)

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Review

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15 pages, 712 KiB

Open AccessReview

Occurrence, Bioaccumulation, and Risk Assessment of Microplastics in the Aquatic Environment: A Review

by Xuemei Li, Liangwen Bao, Yuan Wei, Wensi Zhao, Fanfan Wang, Xuesong Liu, Hailei Su and Ruiqing Zhang

Water 2023, 15(9), 1768; https://doi.org/10.3390/w15091768 - 4 May 2023

Cited by 10 | Viewed by 6201

Abstract

Microplastics (MPs) are emerging as environmental pollutants and are widely distributed in aquatic environments. They are characterized by long life cycles, ease of migration, ability to adsorb other environmental pollutants, small size, and ease of ingestion by aquatic organisms, thereby threatening the growth, [...] Read more.

Microplastics (MPs) are emerging as environmental pollutants and are widely distributed in aquatic environments. They are characterized by long life cycles, ease of migration, ability to adsorb other environmental pollutants, small size, and ease of ingestion by aquatic organisms, thereby threatening the growth, life, and health of aquatic organisms. MPs are biologically transferable and can accumulate in organisms at high trophic levels via food chains, thereby negatively impacting the ecological environment and human health. Moreover, the bioaccumulation of MPs is an important parameter for scientific risk assessments. This paper reviews the current status of MP pollution and its bioaccumulation in marine, freshwater, and other water environments. Furthermore, it proposes relevant recommendations for future research on the bioaccumulation of MPs in conjunction with previous studies to provide basic support for risk assessment and environmental management. Full article

(This article belongs to the Special Issue Advanced Oxidation/Reduction and Biological Processes for Water and Wastewater)

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18 pages, 714 KiB

Open AccessReview

Comparison between Conventional Treatment Processes and Advanced Oxidation Processes in Treating Slaughterhouse Wastewater: A Review

by Jen Xen Yeoh, Siti Nurul Ain Md. Jamil, Fadhil Syukri, Mitsuhiko Koyama and Mohsen Nourouzi Mobarekeh

Water 2022, 14(22), 3778; https://doi.org/10.3390/w14223778 - 21 Nov 2022

Cited by 16 | Viewed by 6698

Abstract

The blooming of the world’s human population and the transition of the human diet into a more westernized, high-protein diet has accelerated the production of slaughterhouse wastewater (SWW) as the number of meat processing plants (MPP) has increased in the past few decades. [...] Read more.

The blooming of the world’s human population and the transition of the human diet into a more westernized, high-protein diet has accelerated the production of slaughterhouse wastewater (SWW) as the number of meat processing plants (MPP) has increased in the past few decades. Conventional treatment processes (CTP) used in treating SWW, such as anaerobic processes, membrane processes, and electrocoagulation, have significant limitations, such as low treatment efficiency, tendency to foul, and high energy consumption, respectively. While advanced oxidation processes (AOPs) appear promising in replacing the former, they lack economic feasibility when used as a single process. In this paper, the limitations and disadvantages of the CTPs used in treating SWW influents are evaluated. The idea of utilising AOPs as a “complementary” step rather than a single process is also discussed. The review paper further explores the variability of different AOPs, such as Fenton, Electro-Fenton, Sono-Fenton, etc., and their respective strengths and weaknesses in counteracting the limitations of CTPs. The idea of incorporating resource recovery into wastewater treatment is also discussed towards the end of the paper as a means of generating additional revenue for the industry players to compensate for the high operation and maintenance costs of SWW treatment. The integration of a new-generation treatment process such as AOP into CTP while being able to carry out resource recovery is a future hurdle that must be overcome by scientists in order to produce a versatile, powerful, sustainable, yet financially feasible and operationally pragmatic treatment system. Full article

(This article belongs to the Special Issue Advanced Oxidation/Reduction and Biological Processes for Water and Wastewater)

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