Molecules

Research

13 pages, 24084 KiB

Open AccessArticle

Upcycling Waste Polyethylene Terephthalate to Produce Nitrogen-Doped Porous Carbon for Enhanced Capacitive Deionization

by Hui Yu, Haiyan Duan, Liang Chen, Weihua Zhu, Daria Baranowska, Yumeng Hua, Dengsong Zhang and Xuecheng Chen

Molecules 2024, 29(20), 4934; https://doi.org/10.3390/molecules29204934 - 18 Oct 2024

Viewed by 581

Abstract

Porous carbon with a high surface area and controllable pore size is needed for energy storage. It is still a significant challenge to produce porous carbon in an economical way. Nitrogen-doped porous carbon (N-PC) was prepared through carbonization of a mixture of waste [...] Read more.

Porous carbon with a high surface area and controllable pore size is needed for energy storage. It is still a significant challenge to produce porous carbon in an economical way. Nitrogen-doped porous carbon (N-PC) was prepared through carbonization of a mixture of waste PET-derived metal–organic frameworks (MOFs) and ammonium. The obtained N-PC exhibits a large surface area and controlled pore size. When utilized as an electrode material for supercapacitors, the N-PC exhibits a specific capacitance of 224 F g⁻¹, significantly surpassing that of commercial activated carbon (AC), which has a capacitance of 111 F g⁻¹. In the subsequent capacitive deionization (CDI) tests, the N-PC demonstrated a maximum salt adsorption capacity of 19.9 mg g⁻¹ at 1.2 V in a NaCl electrolyte (0.5 g L⁻¹), and the salt adsorption capacity increased to 24.7 mg g⁻¹ at 1.4 V. The N-PC electrode also exhibited superior regeneration. The present work not only presents a potential approach to develop cost-effective electrodes for seawater purification but also paves the way for recycling of waste plastics into high value-added products. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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13 pages, 1818 KiB

Open AccessArticle

Effects of Polyethylene Terephthalate Microplastics on Anaerobic Mono-Digestion and Co-Digestion of Fecal Sludge from Septic Tank

by Tingting Ma, Nana Liu, Yuxuan Li, Ziwang Ye, Zhengxian Chen, Shikun Cheng, Luiza C. Campos and Zifu Li

Molecules 2024, 29(19), 4692; https://doi.org/10.3390/molecules29194692 - 3 Oct 2024

Viewed by 832

Abstract

Anaerobic digestion (AD) is one of the most significant processes for treating fecal sludge. However, a substantial amount of microplastics (MPs) have been identified in septic tanks, and it remains unclear whether they impact the resource treatment of feces. To investigate this, polyethylene [...] Read more.

Anaerobic digestion (AD) is one of the most significant processes for treating fecal sludge. However, a substantial amount of microplastics (MPs) have been identified in septic tanks, and it remains unclear whether they impact the resource treatment of feces. To investigate this, polyethylene terephthalate (PET) was used as an indicator of MPs to study their effect on the anaerobic digestion of fecal sludge (FS). Two digestion systems were developed: FS mono-digestion and FS co-digestion with anaerobic granular sludge. The results indicated that the effects of PET varied between the two systems. PET inhibited volatile fatty acid synthesis in both systems, but the inhibition period differed. During mono-digestion, PET slightly increased gas and methane production, in contrast to the co-digestion system, where PET reduced methane production by 75.18%. Furthermore, in the mono-digestion system, PET increased soluble chemical oxygen demand and ammonia nitrogen concentrations while blocking phosphorus release, whereas the co-digestion system showed the opposite effects. Ultimately, the choice of digestion method is crucial for the resource utilization of septic tank sludge, and the impact of MPs on AD cannot be ignored. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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32 pages, 7907 KiB

Open AccessArticle

Degradation Efficiency and Mechanism of Tetracycline in Water by Activated Persulfate Using Biochar-Loaded Nano Zero-Valent Iron

by Bojiao Yan, Xueqi Li, Xiaoyan Wang, Ping Yang, Hai Lu and Xiaoyu Zhang

Molecules 2024, 29(16), 3875; https://doi.org/10.3390/molecules29163875 - 15 Aug 2024

Viewed by 1117

Abstract

Tetracycline (TC) contamination in water is one of the key issues in global environmental protection, and traditional water treatment methods are difficult to remove antibiotic pollutants.Therefore, efficient and environmentally friendly treatment technologies are urgently needed. In this study, activated persulfate (PS) using a [...] Read more.

Tetracycline (TC) contamination in water is one of the key issues in global environmental protection, and traditional water treatment methods are difficult to remove antibiotic pollutants.Therefore, efficient and environmentally friendly treatment technologies are urgently needed. In this study, activated persulfate (PS) using a biochar-loaded nano zero-valent iron (BC-nZVI) advanced oxidation system was used to investigate the degradation effect, influencing factors, and mechanism of TC. BC-nZVI was prepared using the liquid-phase reduction method, and its structure and properties were analyzed by various characterization means. The results showed that nZVI was uniformly distributed on the surface or in the pores of BC, forming a stable complex. Degradation experiments showed that the BC-nZVI/PS system could degrade TC up to 99.57% under optimal conditions. The experiments under different conditions revealed that the iron-carbon ratio, dosing amount, PS concentration, and pH value all affected the degradation efficiency. Free radical burst and electron paramagnetic resonance (EPR) experiments confirmed the dominant roles of hydroxyl and sulfate radicals in the degradation process, and LC–MS experiments revealed the multi-step reaction process of TC degradation. This study provides a scientific basis for the efficient treatment of TC pollution in water. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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21 pages, 1532 KiB

Open AccessArticle

Water Hyacinth Leaves Are an Efficient, Green, and Cost-Effective Biosorbent for the Removal of Metanil Yellow from Aqueous Solution: Kinetics, Isotherm, and Thermodynamic Studies

by Erick Aranda-García, Imelda Guerrero-Coronilla and Eliseo Cristiani-Urbina

Molecules 2024, 29(14), 3409; https://doi.org/10.3390/molecules29143409 - 20 Jul 2024

Viewed by 749

Abstract

Excessive water hyacinth growth in aquatic environments and metanil yellow (MY) dye in industrial wastewater pose severe environmental and public health challenges. Therefore, this study evaluated the effects of various process factors on batch MY biosorption onto water hyacinth leaves (LECs) and MY [...] Read more.

Excessive water hyacinth growth in aquatic environments and metanil yellow (MY) dye in industrial wastewater pose severe environmental and public health challenges. Therefore, this study evaluated the effects of various process factors on batch MY biosorption onto water hyacinth leaves (LECs) and MY biosorption kinetics, equilibrium, and thermodynamics. The optimal pH for MY biosorption by LECs was 1.5–2.0. The initial MY concentration affected the equilibrium MY biosorption capacity but not the LEC particle size and solution temperature. However, the LEC particle size and solution temperature affected the MY biosorption rate; the biosorption rate was higher at a lower particle size (0.15–0.3 mm) and a higher temperature (62 °C) than at higher particle sizes and lower temperatures. The pseudo-second-order model adequately described the biosorption kinetics of MY by LECs at the different levels of the process factors, whereas the Sips and Redlich–Peterson models satisfactorily represented the biosorption isotherm of MY. The Sips model predicted a maximum MY biosorption capacity of 170.8 mg g⁻¹. The biosorption of MY by LECs was endothermic and not spontaneous. These findings demonstrate that LECs exhibit great potential for bioremediating MY-contaminated wastewater, thereby providing valuable insights for effective water treatment and pollution control strategies. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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21 pages, 4626 KiB

Open AccessArticle

Effect of Bi₂MoO₆ Morphology on Adsorption and Visible-Light-Driven Degradation of 2,4-Dichlorophenoxyacetic Acid

by Thi Thanh Hoa Duong, Shuoping Ding, Michael Sebek, Henrik Lund, Stephan Bartling, Tim Peppel, Thanh Son Le and Norbert Steinfeldt

Molecules 2024, 29(14), 3255; https://doi.org/10.3390/molecules29143255 - 10 Jul 2024

Cited by 2 | Viewed by 1195

Abstract

The development of highly efficient and stable visible-light-driven photocatalysts for the removal of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from water is still a challenge. In this work, Bi₂MoO₆ (BMO) materials with different morphology were successfully prepared via a simple hydrothermal method [...] Read more.

The development of highly efficient and stable visible-light-driven photocatalysts for the removal of herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) from water is still a challenge. In this work, Bi₂MoO₆ (BMO) materials with different morphology were successfully prepared via a simple hydrothermal method by altering the solvent. The morphology of the BMO material is mainly influenced by the solvent used in the synthesis (H₂O, ethanol, and ethylene glycol or their mixtures) and to a lesser extent by subsequent thermal annealing. BMO with aggregated spheres and nanoplate-like structures hydrothermally synthesized in ethylene glycol (EG) and subsequently calcined at 400 °C (BMO-400 (EG)) showed the highest adsorption capacity and photocatalytic activity compared to other synthesized morphologies. Complete degradation of 2,4-D on BMO upon irradiation with a blue light-emitting diode (LED, λ_max = 467 nm) was reached within 150 min, resulting in 2,4-dichlorophenol (2,4-DCP) as the main degradation product. Holes (h⁺) and superoxide radicals (⋅O₂⁻) are assumed to be the reactive species observed for the rapid conversion of 2,4-D to 2,4-DCP. The addition of H₂O₂ to the reaction mixture not only accelerates the degradation of 2,4-DCP but also significantly reduces the total organic carbon (TOC) content, indicating that hydroxyl radicals are crucial for the rapid mineralization of 2,4-D. Under optimal conditions, the TOC value was reduced by 84.5% within 180 min using BMO-400 (EG) and H₂O₂. The improved degradation performance of BMO-400 (EG) can be attributed to its particular morphology leading to lower charge transfer resistance, higher electron–hole separation, and larger specific surface area. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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23 pages, 2961 KiB

Open AccessArticle

Equilibrium, Kinetic, and Diffusion Mechanism of lead(II) and cadmium(II) Adsorption onto Commercial Activated Carbons

by Joanna Lach and Ewa Okoniewska

Molecules 2024, 29(11), 2418; https://doi.org/10.3390/molecules29112418 - 21 May 2024

Viewed by 1167

Abstract

The adsorption of Pb(II) and Cd(II) on three commercial microporous activated carbons was analysed. Adsorption kinetics and statistics were investigated, and the results were described with different models. The highest values of the correlation coefficient R² were obtained for the pseudo-second-order kinetics [...] Read more.

The adsorption of Pb(II) and Cd(II) on three commercial microporous activated carbons was analysed. Adsorption kinetics and statistics were investigated, and the results were described with different models. The highest values of the correlation coefficient R² were obtained for the pseudo-second-order kinetics model for all ions tested and all sorbents used. The adsorption process was found to be determined by both diffusion in the liquid layer and intraparticle diffusion. The adsorption equilibrium is very well described by Langmuir, Temkin, Thoth or Jovanovic isotherm models. Based on the values of n from the Freundlich isotherm and K_L from the Langmuir isotherm, the adsorption of cadmium and lead ions was found to be favourable. The highest monolayer capacities were obtained during the adsorption of lead ions (162.19 mg/g) and for cadmium (126.34 mg/g) for activated carbon WG-12. This carbon is characterised by the highest amount of acid functional groups and the largest specific surface area. The adsorption efficiency of the tested ions from natural water is lower than that from a model solution made from deionised water. The lowest efficiencies are obtained when the process occurs from highly mineralised water. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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16 pages, 5734 KiB

Open AccessArticle

Enhanced Chromium (VI) Removal by Micron-Scale Zero-Valent Iron Pretreated with Aluminum Chloride under Aerobic Conditions

by Xuejun Long, Rui Li, Jun Wan, Zhenxing Zhong, Yuxuan Ye, Jiazhi Yang, Jun Luo, Jin Xia and Yaomeng Liu

Molecules 2024, 29(10), 2350; https://doi.org/10.3390/molecules29102350 - 16 May 2024

Cited by 1 | Viewed by 943

Abstract

Micron-scale zero-valent iron (ZVI)-based material has been applied for hexavalent chromium (Cr(VI)) decontamination in wastewater treatment and groundwater remediation, but the passivation problem has limited its field application. In this study, we combined aluminum chloride solution with ZVI (pcZVI-AlCl₃) to enhance [...] Read more.

Micron-scale zero-valent iron (ZVI)-based material has been applied for hexavalent chromium (Cr(VI)) decontamination in wastewater treatment and groundwater remediation, but the passivation problem has limited its field application. In this study, we combined aluminum chloride solution with ZVI (pcZVI-AlCl₃) to enhance Cr(VI) removal behavior under aerobic conditions. The optimal pre-corrosion conditions were found to be 2.5 g/L ZVI, 0.5 mM AlCl₃, and a 4 h preconditioning period. Different kinds of techniques were applied to detect the properties of preconditioned ZVI and corrosion products. The ⁵⁷Fe Mössbauer spectra showed that proportions of ZVI, Fe₃O₄, and FeOOH in pcZVI-AlCl₃ were 49.22%, 34.03%, and 16.76%, respectively. The formation of Al(OH)₃ in the corrosion products improved its pH_pzc (point of zero charge) for Cr(VI) adsorption. Continuous-flow experiments showed its great potential for Cr(VI) removal in field applications. The ZVI and corrosion products showed a synergistic effect in enhancing electron transfer for Cr(VI) removal. The mechanisms underlying Cr(VI) removal by pcZVI-AlCl₃ included adsorption, reduction, and precipitation, and the contribution of adsorption was less. This work provides a new strategy for ZVI pre-corrosion to improve its longevity and enhance Cr(VI) removal. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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18 pages, 6062 KiB

Open AccessArticle

Unraveling the Impact of Adsorbed Molecules on Photocatalytic Processes: Advancements in Understanding Facet-Controlled Semiconductor Photocatalysts

by Anna Kusior, Kinga Michalec, Anna Micek-Ilnicka and Marta Radecka

Molecules 2024, 29(10), 2290; https://doi.org/10.3390/molecules29102290 - 13 May 2024

Viewed by 826

Abstract

This work aims to demonstrate that the Fe₂O₃ nanocrystals’ adsorptive and photocatalytic properties can be adjusted by exposing the crystal facets that are functionalized. To this end, cube- and disc-like structures were synthesized using a metal ion-mediated hydrothermal route. Thereafter, [...] Read more.

This work aims to demonstrate that the Fe₂O₃ nanocrystals’ adsorptive and photocatalytic properties can be adjusted by exposing the crystal facets that are functionalized. To this end, cube- and disc-like structures were synthesized using a metal ion-mediated hydrothermal route. Thereafter, some of the samples were annealed at 500 °C for 3 h. Our paper combines the experimental part with theoretical calculations of the obtained materials’ band edge positions. The results reveal that—aside from hematite—the as-synthesized discs also contain γ-FeOOH and β-Fe₂O₃ phases, which transform into α-Fe₂O₃ during annealing. The hydrodynamic diameter, zeta potential, and adsorption kinetics measurements show that the cube-like samples exhibit the highest affinity for cationic, whereas the discs have an affinity for anionic dye. Measurements of the wall zeta potential also reveal that annealing the discs modifies their surface state and ability to adsorb molecules. Photocatalytic tests show that the as-synthesized powders have better photocatalytic performance toward methylene blue decomposition than the annealed ones. The observed small changes in the concentration of the MO during illumination result from the energy band structure of the cube-like crystal orientation. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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13 pages, 17650 KiB

Open AccessArticle

The Simultaneous Efficient Recovery of Ammonia Nitrogen and Phosphate Resources in the Form of Struvite: Optimization and Potential Applications for the Electrochemical Reduction of NO₃⁻

by Liping Li, Jingtao Bi, Mengmeng Sun, Shizhao Wang, Xiaofu Guo, Fei Li, Jie Liu and Yingying Zhao

Molecules 2024, 29(10), 2185; https://doi.org/10.3390/molecules29102185 - 8 May 2024

Viewed by 1103

Abstract

In response to the need for improvement in the utilization of ammonium-rich solutions after the electrochemical reduction of nitrate (NO₃⁻–RR), this study combined phosphorus-containing wastewater and adopted the electrochemical precipitation method for the preparation of struvite (MAP) to simultaneously recover [...] Read more.

In response to the need for improvement in the utilization of ammonium-rich solutions after the electrochemical reduction of nitrate (NO₃⁻–RR), this study combined phosphorus-containing wastewater and adopted the electrochemical precipitation method for the preparation of struvite (MAP) to simultaneously recover nitrogen and phosphorus resources. At a current density of 5 mA·cm⁻² and an initial solution pH of 7.0, the recovery efficiencies for nitrogen and phosphorus can reach 47.15% and 88.66%, respectively. Under various experimental conditions, the generated struvite (MgNH₄PO₄·6H₂O) exhibits a typical long prismatic structure. In solutions containing nitrate and nitrite, the coexisting ions have no significant effect on the final product, struvite. Finally, the characterization of the precipitate product by X-ray diffraction (XRD) revealed that its main component is struvite, with a high purity reaching 93.24%. Overall, this system can effectively recover ammonium nitrogen from the NO₃⁻–RR solution system after nitrate reduction, with certain application prospects for the recovery of ammonium nitrogen and phosphate. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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17 pages, 3638 KiB

Open AccessArticle

Efficient Recovery of Phosphate from Water Media by Iron-Magnesium Functionalized Lignite: Adsorption Evaluation, Mechanism Revelation and Potential Application Exploration

by Wenbo An, Qiqi Wang, He Chen, Yifan Liu, Xuechun Hu and Junzhen Di

Molecules 2024, 29(6), 1252; https://doi.org/10.3390/molecules29061252 - 12 Mar 2024

Viewed by 1381

Abstract

Selective phosphorus removal from aquatic media has become an ideal strategy to mitigate eutrophication and meet increasingly stringent discharge requirements. To achieve phosphorus control and resource utilization of low-calorific-value lignite, iron and magnesium salts were used to functionalize lignite, and iron–magnesium functionalized lignite [...] Read more.

Selective phosphorus removal from aquatic media has become an ideal strategy to mitigate eutrophication and meet increasingly stringent discharge requirements. To achieve phosphorus control and resource utilization of low-calorific-value lignite, iron and magnesium salts were used to functionalize lignite, and iron–magnesium functionalized lignite (called IM@BC) was prepared for phosphate recovery from water media. The adsorption properties of IM@BC were systematically evaluated, especially the influence of ambient pH and co-existing ions. The kinetic, isothermal, and thermodynamic adsorption behaviors of IM@BC were analyzed. The adsorption mechanism was revealed by microscopic characterization. The potential application of phosphate-containing IM@BC (P-IM@BC) was explored. The results show that IM@BC has a strong phosphate adsorption capacity, and the maximum adsorption capacity is 226.22 mgP/g at pH = 3. Co-existing CO₃²⁻ inhibits phosphate adsorption, while coexisting Ca²⁺ and Mg²⁺ enhance the effect. At the initial adsorption stage, the amount of phosphate adsorbed by IM@BC continues to increase, and the adsorption equilibrium state is gradually reached after 24 h. The adsorption process conforms to the pseudo-second-order kinetic model (PSO) and Langmuir isothermal adsorption model, and the adsorption process is mainly chemical adsorption. The phosphate absorption capacity is positively correlated with temperature (283.15 K~313.15 K), and the adsorption process is spontaneous, endothermic, and entropy-increasing. Its adsorption mechanism includes electrostatic attraction, ion exchange, surface precipitation, and coordination exchange. IM@BC can efficiently recover phosphate from actual phosphorus-containing wastewater with a recovery efficiency of up to 90%. P-IM@BC slowly releases phosphate from pH 3 to 11. Plant growth experiments showed that P-IM@BC could be used as a slow-release fertilizer to promote the root growth of cowpeas. The novelty of this work lies in the development of a highly efficient phosphate recovery adsorbent, which provides a feasible method of phosphorus control in water media and resource utilization of lignite. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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Review

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26 pages, 2118 KiB

Open AccessReview

Role of Clay Minerals in Natural Media Self-Regeneration from Organic Pollution-Prospects for Nature-Inspired Water Treatments

by Abdelkrim Azzouz, David Dewez, Amina Benghaffour, Robert Hausler and René Roy

Molecules 2024, 29(21), 5108; https://doi.org/10.3390/molecules29215108 - 29 Oct 2024

Viewed by 481

Abstract

Pollution from organic molecules is a major environmental issue that needs to be addressed because of the negative impacts of both the harmfulness of the molecule structures and the toxicity that can spread through natural media. This is mainly due to their unavoidable [...] Read more.

Pollution from organic molecules is a major environmental issue that needs to be addressed because of the negative impacts of both the harmfulness of the molecule structures and the toxicity that can spread through natural media. This is mainly due to their unavoidable partial oxidation under exposure to air and solar radiation into diverse derivatives. Even when insoluble, the latter can be dispersed in aqueous media through solvatation and/or complexation with soluble species. Coagulation–flocculation, biological water treatments or adsorption on solids cannot result in a total elimination of organic pollutants. Chemical degradation by chlorine and/or oxygen-based oxidizing agents is not a viable approach due to incomplete mineralization into carbon dioxide and other oxides. A more judicious strategy resides in mimicking natural oxidation under ambient conditions. Soils and aqueous clay suspensions are known to display adsorptive and catalytic properties, and slow and complete self-regeneration can be achieved in an optimum time frame with a much slower pollution throughput. A deep knowledge of the behavior of aluminosilicates and of oxidizing species in soils and aquatic media allows us to gain an understanding of their roles in natural oxidative processes. Their individual and combined contributions will be discussed in the present critical analysis of the reported literature. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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17 pages, 9043 KiB

Open AccessReview

Composite 2D Material-Based Pervaporation Membranes for Liquid Separation: A Review

by Roberto Castro-Muñoz

Molecules 2024, 29(12), 2829; https://doi.org/10.3390/molecules29122829 - 13 Jun 2024

Viewed by 1186

Abstract

Today, chemistry and nanotechnology cover molecular separations in liquid and gas states by aiding in the design of new nano-sized materials. In this regard, the synthesis and application of two-dimensional (2D) nanomaterials are current fields of research in which structurally defined 2D materials [...] Read more.

Today, chemistry and nanotechnology cover molecular separations in liquid and gas states by aiding in the design of new nano-sized materials. In this regard, the synthesis and application of two-dimensional (2D) nanomaterials are current fields of research in which structurally defined 2D materials are being used in membrane separation either in self-standing membranes or composites with polymer phases. For instance, pervaporation (PV), as a highly selective technology for liquid separation, benefits from using 2D materials to selectively transport water or other solvent molecules. Therefore, this review paper offers an interesting update in revising the ongoing progress of PV membranes using 2D materials in several applications, including solvent purification (the removal of water from organic systems), organics removal (the removal of organic molecules diluted in water systems), and desalination (selective water transport from seawater). In general, recent reports from the past 3 years have been discussed and analyzed. Attention has been devoted to the proposed strategies and fabrication of membranes for the inclusion of 2D materials into polymer phases. Finally, the future trends and current research gaps are declared for the scientists in the field. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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12 pages, 2360 KiB

Open AccessReview

Research Progress of Ozone/Peroxymonosulfate Advanced Oxidation Technology for Degrading Antibiotics in Drinking Water and Wastewater Effluent: A Review

by Hai Lu, Xinglin Chen, Qiao Cong, Qingpo Li, Xiaoyan Wang, Shuang Zhong, Huan Deng and Bojiao Yan

Molecules 2024, 29(5), 1170; https://doi.org/10.3390/molecules29051170 - 6 Mar 2024

Cited by 3 | Viewed by 1881

Abstract

Nowadays, antibiotics are widely used, increasing the risk of contamination of the water body and further threatening human health. The traditional water treatment process is less efficient in degrading antibiotics, and the advanced oxidation process (AOPs) is cleaner and more efficient than the [...] Read more.

Nowadays, antibiotics are widely used, increasing the risk of contamination of the water body and further threatening human health. The traditional water treatment process is less efficient in degrading antibiotics, and the advanced oxidation process (AOPs) is cleaner and more efficient than the traditional biochemical degradation process. The combined ozone/peroxymonosulfate (PMS) advanced oxidation process (O₃/PMS) based on sulfate radical (SO₄^•−) and hydroxyl radical (•OH) has developed rapidly in recent years. The O₃/PMS process has become one of the most effective ways to treat antibiotic wastewater. The reaction mechanism of O₃/PMS was reviewed in this paper, and the research and application progress of the O₃/PMS process in the degradation of antibiotics in drinking water and wastewater effluent were evaluated. The operation characteristics and current application range of the process were summarized, which has a certain reference value for further research on O₃/PMS process. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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29 pages, 8326 KiB

Open AccessReview

Efficient Adsorption of Nitrogen and Phosphorus in Wastewater by Biochar

by Xichang Wu, Wenxuan Quan, Qi Chen, Wei Gong and Anping Wang

Molecules 2024, 29(5), 1005; https://doi.org/10.3390/molecules29051005 - 26 Feb 2024

Cited by 6 | Viewed by 3835

Abstract

Nitrogen and phosphorus play essential roles in ecosystems and organisms. However, with the development of industry and agriculture in recent years, excessive N and P have flowed into water bodies, leading to eutrophication, algal proliferation, and red tides, which are harmful to aquatic [...] Read more.

Nitrogen and phosphorus play essential roles in ecosystems and organisms. However, with the development of industry and agriculture in recent years, excessive N and P have flowed into water bodies, leading to eutrophication, algal proliferation, and red tides, which are harmful to aquatic organisms. Biochar has a high specific surface area, abundant functional groups, and porous structure, which can effectively adsorb nitrogen and phosphorus in water, thus reducing environmental pollution, achieving the reusability of elements. This article provides an overview of the preparation of biochar, modification methods of biochar, advancements in the adsorption of nitrogen and phosphorus by biochar, factors influencing the adsorption of nitrogen and phosphorus in water by biochar, as well as reusability and adsorption mechanisms. Furthermore, the difficulties encountered and future research directions regarding the adsorption of nitrogen and phosphorus by biochar were proposed, providing references for the future application of biochar in nitrogen and phosphorus adsorption. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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Other

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17 pages, 2354 KiB

Open AccessPerspective

Research Progress on the Degradation of Organic Pollutants in Water by Activated Persulfate Using Biochar-Loaded Nano Zero-Valent Iron

by Hai Lu, Xiaoyan Wang, Qiao Cong, Xinglin Chen, Qingpo Li, Xueqi Li, Shuang Zhong, Huan Deng and Bojiao Yan

Molecules 2024, 29(5), 1130; https://doi.org/10.3390/molecules29051130 - 3 Mar 2024

Cited by 1 | Viewed by 2174

Abstract

Biochar (BC) is a new type of carbon material with a high specific surface area, porous structure, and good adsorption capacity, which can effectively adsorb and enrich organic pollutants. Meanwhile, nano zero-valent iron (nZVI) has excellent catalytic activity and can rapidly degrade organic [...] Read more.

Biochar (BC) is a new type of carbon material with a high specific surface area, porous structure, and good adsorption capacity, which can effectively adsorb and enrich organic pollutants. Meanwhile, nano zero-valent iron (nZVI) has excellent catalytic activity and can rapidly degrade organic pollutants through reduction and oxidation reactions. The combined utilization of BC and nZVI can not only give full play to their advantages in the adsorption and catalytic degradation of organic pollutants, but also help to reduce the agglomeration of nZVI, thus improving its efficiency in water treatment and providing strong technical support for water resources protection and environmental quality improvement. This article provides a detailed introduction to the preparation method and characterization technology, reaction mechanism, influencing factors, and specific applications of BC and nZVI, and elaborates on the research progress of BC-nZVI in activating persulfate (PS) to degrade organic pollutants in water. It has been proven experimentally that BC-nZVI can effectively remove phenols, dyes, pesticides, and other organic pollutants. Meanwhile, in response to the existing problems in current research, this article proposes future research directions and challenges, and summarizes the application prospects and development trends of BC-nZVI in water treatment. In summary, BC-nZVI-activated PS is an efficient technology for degrading organic pollutants in water, providing an effective solution for protecting water resources and improving environmental quality, and has significant application value. Full article

(This article belongs to the Special Issue Wastewater Treatment: Functional Materials and Advanced Technology, 2nd Edition)

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