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Hao L, Ma H, Xing B. Surface characteristics and adsorption properties of polypropylene microplastics by ultraviolet irradiation and natural aging. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 944:173962. [PMID: 38876352 DOI: 10.1016/j.scitotenv.2024.173962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/23/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
The vast application and deep integration of plastic commodity with our human lives raise a great concern about the ubiquitous microplastics (MPs) in nature, yet the environmental behavior of MPs remain unclear. As a main type and candidate of MPs, pristine polypropylene MPs (PP-MP-Pris), as well as the influence of ultraviolet (UV) irradiation on the degree of aging and surface characteristics, were characterized quantitatively by Fourier infrared spectroscopy, scanning electron microscopy, contact angle meter, automatic specific surface area and pore analyzer and laser particle analyzer, with natural aged PP-MPs (PP-MP-Age) as comparison. The carbonyl index (CI) of UV aged PP-MPs (PP-MP-U) was increased with extension of exposure time, while biofilm with abundant functional groups and the maximum CI value were the characteristics of PP-MP-Age. Moreover, the adsorption capacity of PP-MP-U for crystal violet (CV) was increased and reached the maximum after 30 days, while that of PP-MP-Age was weakened, probably due to the enhanced hydrophilicity and the shedding of calcium carbonate (CaCO3) during the natural aging process, which was demonstrated by hydrochloric acid treatment, indicating the vital involvement of CaCO3. Moreover, the better fitting to PSO kinetics and Freundlich isotherm models indicated that the multilayered and non-homogeneous surface adsorption was acted as the rate-controlling step. Furthermore, the positive values of ΔGθ, ΔHθ and ΔSθ indicated that the adsorption was a non-spontaneous, endothermic process with increased degree of the freedom on the interface of PP-MPs and CV solution. The presence of divalent salts inhibited CV adsorption, demonstrating that electrostatic attraction played a major role in CV capture. The hydrophobic interaction, micropore filling, hydrogen bonding, and π - π conjugation were possible involved. This study is of great significance for better understanding the complex pollution of MPs and its potential environmental risks in the future.
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Affiliation(s)
- Lin Hao
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'An, Shaanxi 710119, PR China
| | - Hongzhu Ma
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'An, Shaanxi 710119, PR China.
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA
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2
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Jeong SS, Park BJ, Yoon JH, Kirkham MB, Yang JE, Kim HS. Mechanistic Evidence for Hg Removal from Wastewater by Biologically Produced Sulfur. TOXICS 2024; 12:278. [PMID: 38668501 PMCID: PMC11053473 DOI: 10.3390/toxics12040278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/03/2024] [Accepted: 04/08/2024] [Indexed: 04/29/2024]
Abstract
A significant quantity of biologically produced sulfur (BPS) is generated as a by-product of chemical and biological desulfurization processes applied to landfill gas treatment. The beneficial upcycling of BPS has seen limited use in the environmental context. The effectiveness and underlying mechanism of BPS as an adsorbent for removing Hg2+ from both solution and wastewater were elucidated based on experiments encompassing surface characterization, adsorption isotherms, kinetics, and thermodynamics. The BPS exhibited remarkable efficacy in removing Hg2+ from solution, with the Langmuir model accurately describing the adsorption process and showing a maximum adsorption capacity of 244 mg g-1. Surface analysis through X-ray photoelectron spectroscopy and scanning electron microscopy revealed that Hg2+ complexed with sulfide on BPS surfaces, forming stable HgS. The adsorbed Hg was strongly retained in BPS, with less than 0.2% of the adsorbed Hg desorbed by strong acids. Adsorption kinetics followed the double-exponential first-order model, showing an initial rapid adsorption phase wherein 75% of the initial Hg2+ was removed within 5 min, followed by a slower adsorption rate. The thermodynamic parameters suggested that adsorption of Hg2+ by BPS was a spontaneous and endothermic process. Additionally, BPS effectively removed Hg2+ from wastewater, showing preference for Hg over other co-existing metals. These findings underscore the potential of BPS as an effective adsorbent for Hg2+ removal from wastewater.
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Affiliation(s)
- Seok-Soon Jeong
- Department of Biological Environment, Kangwon National University, Chuncheon 24341, Republic of Korea; (S.-S.J.); (B.-J.P.); (J.-H.Y.); (J.-E.Y.)
| | - Byung-Jun Park
- Department of Biological Environment, Kangwon National University, Chuncheon 24341, Republic of Korea; (S.-S.J.); (B.-J.P.); (J.-H.Y.); (J.-E.Y.)
| | - Jung-Hwan Yoon
- Department of Biological Environment, Kangwon National University, Chuncheon 24341, Republic of Korea; (S.-S.J.); (B.-J.P.); (J.-H.Y.); (J.-E.Y.)
| | - Mary Beth Kirkham
- Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA;
| | - Jae-E. Yang
- Department of Biological Environment, Kangwon National University, Chuncheon 24341, Republic of Korea; (S.-S.J.); (B.-J.P.); (J.-H.Y.); (J.-E.Y.)
| | - Hyuck-Soo Kim
- Department of Biological Environment, Kangwon National University, Chuncheon 24341, Republic of Korea; (S.-S.J.); (B.-J.P.); (J.-H.Y.); (J.-E.Y.)
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3
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Du T, Qian L, Shao S, Xing T, Li T, Wu L. Comparison of sulfide-induced transformation of biodegradable and conventional microplastics: Mechanism and environmental fate. WATER RESEARCH 2024; 253:121295. [PMID: 38354663 DOI: 10.1016/j.watres.2024.121295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/31/2024] [Accepted: 02/08/2024] [Indexed: 02/16/2024]
Abstract
Biodegradable plastics have been massively produced and used as potential substitutes for conventional plastics, resulting in their inevitable entry into the environment and generation of biodegradable microplastics (MPs). The sulfidation transformation of MPs is an important process for their transformation in anoxic environments (e.g., sediments, anaerobic activated sludges) that can alter their environmental effects and risks. However, how sulfides induce the transformation of biodegradable MPs and whether they are similar to conventional MPs remains unknown. In the present study, we compared the transformation and mechanism of conventional polyethylene (PE) MPs and biodegradable poly(butylene adipate-co-terephthalate) (PBAT) MPs during sulfidation. The results demonstrated that sulfidation resulted in oxidation of PE MPs, whereas PBAT MPs underwent reduction and had higher physical damage, as evidenced by fragmentation, chain scission and organic compound release. Besides, reactive oxygen species and sulfide species played important roles in the sulfidation of PE and PBAT MPs, respectively. The presence of ester groups in PBAT MPs led to their hydrolysis, causing chain scission and further reduction. Furthermore, sulfidation caused a higher degree of adsorption and toxicity alterations in PBAT MPs than in PE MPs. This work uncovers critical abiotic transformation behaviors of biodegradable microplastics and highlights the necessity of considering microplastic structural features to accurately predict microplastic occurrence.
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Affiliation(s)
- Tingting Du
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China.
| | - Liwen Qian
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Song Shao
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Tianran Xing
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Tong Li
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China.
| | - Lijun Wu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
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Li X, Guo S, Shen D, Shentu J, Lv L, Qi S, Zhu M, Long Y. Microplastic release and sulfate reduction response in the early stage of a simulated landfill. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 175:22-29. [PMID: 38150952 DOI: 10.1016/j.wasman.2023.12.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 12/16/2023] [Accepted: 12/18/2023] [Indexed: 12/29/2023]
Abstract
Landfills are essential facilities for treating and disposing municipal solid waste. They emit sulfur-containing odors and serve as an important sink for a new type of pollutant called microplastics (MPs). This study focused on the initial stage of anaerobic degradation to establish the relationship between the release of MPs and odor generation. Our findings show the rapid release of MPs into the leachate in the early stage of landfill and their predominant accumulation in the leachate sediment. The circulating leachate contained 1.45 times higher concentrations of MPs than the noncirculating leachate, with a peak concentration of 39 items·L-1. In addition, fragmentation of MPs occurred. The percentage of MPs with particle sizes of 2.5-5 mm decreased from 66.70 % to 22.32 %, while those measuring 0.1-0.5 mm increased by 33.12 %. A positive correlation was observed between MP release and sulfate reduction. Although leachate circulation increased the release of MPs, it also reduced the overall release time and total amount of MPs exported from the landfill. Compared with the initial landfill waste, the leachate operation mode, regardless of circulation, resulted in a 6.15-8.93-fold increase in MP release. These findings provide a valuable foundation for the simultaneous regulation of traditional pollutant odor and new pollutants (MPs) in landfills.
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Affiliation(s)
- Xianghang Li
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Shuli Guo
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Dongsheng Shen
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Jiali Shentu
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Li Lv
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Shengqi Qi
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Min Zhu
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China
| | - Yuyang Long
- Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
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Zhou X, Wang Y, Liu R, Mo B, Li D, He L, Wang Y, Wang Y, Zheng H, Li F. Adsorption and desorption of Hg(II) by four aged microplastics and its effects on gaseous elemental mercury production in seawater. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 272:116036. [PMID: 38325271 DOI: 10.1016/j.ecoenv.2024.116036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/16/2024] [Accepted: 01/26/2024] [Indexed: 02/09/2024]
Abstract
Microplastics (MPs) weather after entering the environment gradually, and the interaction with metal ions in the aqueous environment has received extensive attention. However, there are few studies on Hg(Ⅱ), especially the effect of MPs on the release of Hg0(DEM) in water after entering the aqueous environment. In this study, four types of MPs (PP, PE, PET, PVC) were selected to study the adsorption and desorption behavior of Hg(Ⅱ) after photoaging and to explore the influence of MPs on the release of DEM in seawater under different lighting conditions. The results showed that the specific surface area, negative charges, and oxygen-containing functional group of MPs increased after aging. The adsorption capacity of aged MPs for Hg(Ⅱ) was significantly improved, which was consistent with the pseudo-first-order and pseudo-second-order model, indicating that the adsorption process was a chemical and physical adsorption. The fitting results of the in-particle diffusion model indicated that the adsorption was controlled by multiple steps. Hg(Ⅱ) was easier to desorb in the simulated gastric fluid environment. Because the aged MPs had the stronger binding force to Hg(Ⅱ), their desorption rate is lower than new MPs. Under visible light and UVA irradiation, MPs inhibited the release of Hg0. Under UVA, the mass of DEM produced in seawater with aged PE and PVC was higher than that of new PE and PVC. The aged PE and PVC could produce more ·O2-, which was conducive to the reduction of mercury. However, in UVB irradiation, the addition of MPs promoted the release of DEM, and ·O2- also played an important contribution in affecting the photochemical reaction of mercury. Therefore, the presence of aged MPs will significantly affect the water-air exchange of Hg in water. Compared with new MPs, aged MPs improved the contribution of free radicals in Hg transformation by releasing reactive oxygen species. This study extends the understanding of the effects of MPs on the geochemical cycle of Hg(Ⅱ) in seawater, better assesses the potential combined ecological risks of MPs and Hg(Ⅱ), and provides certain guidance for the pollution prevention and control of MPs.
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Affiliation(s)
- Xuyuan Zhou
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yan Wang
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Ruhai Liu
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
| | - Bing Mo
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Dongting Li
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Likun He
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yudong Wang
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Yunxu Wang
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Hao Zheng
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Fengmin Li
- Key Laboratory of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
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Li L, Xue B, Lin H, Lan W, Wang X, Wei J, Li M, Li M, Duan Y, Lv J, Chen Z. The adsorption and release mechanism of different aged microplastics toward Hg(II) via batch experiment and the deep learning method. CHEMOSPHERE 2024; 350:141067. [PMID: 38163463 DOI: 10.1016/j.chemosphere.2023.141067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/03/2024]
Abstract
Aged microplastics are ubiquitous in the aquatic environment, which inevitably accumulate metals, and then alter their migration. Whereas, the synergistic behavior and effect of microplastics and Hg(II) were rarely reported. In this context, the adsorptive behavior of Hg(II) by pristine/aged microplastics involving polystyrene, polyethylene, polylactic acid, and tire microplastics were investigated via kinetic (pseudo-first and second-order dynamics, the internal diffusion model), Langmuir, and Freundlich isothermal models; the adsorption and desorption behavior was also explored under different conditions. Microplastics aged by ozone exhibited a rougher surface attached with abundant oxygen-containing groups to enhance hydrophilicity and negative surface charge, those promoted adsorption capacity of 4-20 times increment compared with the pristine microplastics. The process (except for aged tire microplastics) was dominated by a monolayer chemical reaction, which was significantly impacted by pH, salinity, fulvic acid, and co-existing ions. Furthermore, the adsorbed Hg(II) could be effectively eluted in 0.04% HCl, simulated gastric liquids, and seawater with a maximum desorption amount of 23.26 mg/g. An artificial neural network model was used to predict the performance of microplastics in complex media and accurately capture the main influencing factors and their contributions. This finding revealed that aged microplastics had the affinity to trap Hg(II) from freshwater, whereafter it released the Hg(II) once transported into the acidic medium, the organism's gastrointestinal system, or the estuary area. These indicated that aged microplastics could be the sink or the source of Hg(II) depending on the surrounding environment, meaning that aged microplastics could be the vital carrier to Hg(II).
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Affiliation(s)
- Lianghong Li
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
| | - Bin Xue
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
| | - Haiying Lin
- School of Resources, Environment and Materials, Guangxi University, Nanning, China; Guangxi Key Laboratory of Emerging Contaminants Monitoring, Early Warning and Environmental Health Risk Assessment, Guangxi University, Nanning, China.
| | - Wenlu Lan
- Beibu Gulf Marine Ecological Environment Field Observation and Research Station of Guangxi, Beihai, Guangxi, China; Marine Environmental Monitoring Centre of Guangxi, Beihai, Guangxi, China.
| | - Xinyi Wang
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
| | - Junqi Wei
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
| | - Mingen Li
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
| | - Mingzhi Li
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
| | - Yu Duan
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
| | - Jiatong Lv
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
| | - Zixuan Chen
- School of Resources, Environment and Materials, Guangxi University, Nanning, China
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Gao Z, Cizdziel JV, Wontor K, Olubusoye BS. Adsorption/desorption of mercury (II) by artificially weathered microplastics: Kinetics, isotherms, and influencing factors. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 337:122621. [PMID: 37757936 DOI: 10.1016/j.envpol.2023.122621] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 09/29/2023]
Abstract
While both mercury (Hg) and microplastics (MPs) are well-studied global pollutants, comparatively little is known about the interactions between them and the mobilization of Hg from MPs into organisms. We examined the affinity of Hg(II) to artificially weathered MPs, including polyamide (w-PA), polyethylene (w-PE), polyethylene terephthalate (w-PET), polyester fibers (w-PEST), polyvinyl chloride (w-PVC), and polylactic acid (w-PLA), along with crumb rubber (CR) and PE collected from a wastewater treatment plant (WWTP-PE). WWTP-PE, CR, and w-PEST had particularly high Hg(II) affinities, which can be attributed to electrostatic interaction and pore filling. The adsorption followed a pseudo-second-order kinetic process and fitted the Freundlich model, suggesting multi-step (mass transfer and intraparticle diffusion) and heterogeneous adsorptions. Hydrochemical conditions (pH, dissolved organic matter (DOM), salinity and co-existent metal ions) all impacted Hg-MP behavior. Changes in Hg speciation and MP surface properties contributed to the different Hg(II) adsorption capacities for the MPs. Weathering of MPs generally increased the adsorption of Hg(II) onto MPs, but CR, PET and PEST did not follow this trend. Less than 3% of adsorbed Hg(II) was mobilized from the MPs in freshwater, but that increased up to 73% under simulated avian digestive conditions, suggesting increased bioavailability of Hg(II) from ingested MPs. Overall, weathered MPs adsorb and retain Hg(II) under environmentally relevant conditions but desorb much of it in simulated avian digestion fluid, suggesting that birds that ingest MPs may have increased Hg(II) exposure.
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Affiliation(s)
- Zhiqiang Gao
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS, 38677, USA
| | - James V Cizdziel
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS, 38677, USA.
| | - Kendall Wontor
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS, 38677, USA
| | - Boluwatife S Olubusoye
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS, 38677, USA
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Qiu Y, Li Z, Zhang T, Zhang P. Predicting aqueous sorption of organic pollutants on microplastics with machine learning. WATER RESEARCH 2023; 244:120503. [PMID: 37639990 DOI: 10.1016/j.watres.2023.120503] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/31/2023]
Abstract
Microplastics (MPs) are ubiquitously distributed in freshwater systems and they can determine the environmental fate of organic pollutants (OPs) via sorption interaction. However, the diverse physicochemical properties of MPs and the wide range of OP species make a deeper understanding of sorption mechanisms challenging. Traditional isotherm-based sorption models are limited in their universality since they normally only consider the nature and characteristics of either sorbents or sorbates individually. Therefore, only specific equilibrium concentrations or specific sorption isotherms can be used to predict sorption. To systematically evaluate and predict OP sorption under the influence of both MPs and OPs properties, we collected 475 sorption data from peer-reviewed publications and developed a poly-parameter-linear-free-energy-relationship-embedded machine learning method to analyze the collected sorption datasets. Models of different algorithms were compared, and the genetic algorithm and support vector machine hybrid model displayed the best prediction performance (R2 of 0.93 and root-mean-square-error of 0.07). Finally, comparison results of three feature importance analysis tools (forward step wise method, Shapley method, and global sensitivity analysis) showed that chemical properties of MPs, excess molar refraction, and hydrogen-bonding interaction of OPs contribute the most to sorption, reflecting the dominant sorption mechanisms of hydrophobic partitioning, hydrogen bond formation, and π-π interaction, respectively. This study presents a novel sorbate-sorbent-based ML model with a wide applicability to expand our capacity in understanding the complicated process and mechanism of OP sorption on MPs.
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Affiliation(s)
- Ye Qiu
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macau SAR
| | - Zhejun Li
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macau SAR
| | - Tong Zhang
- College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, 38 Tongyan Rd., Tianjin 300350, China
| | - Ping Zhang
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macau SAR.
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9
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Qiu Y, Zhang T, Zhang P. Fate and environmental behaviors of microplastics through the lens of free radical. JOURNAL OF HAZARDOUS MATERIALS 2023; 453:131401. [PMID: 37086675 DOI: 10.1016/j.jhazmat.2023.131401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Microplastics (MPs), as plastics with a size of less than 5 mm, are ubiquitously present in the environment and become an increasing environmental concern. The fate and environmental behavior of MPs are significantly influenced by the presence of free radicals. Free radicals can cause surface breakage, chemical release, change in crystallinity and hydrophilicity, and aggregation of MPs. On the other hand, the generation of free radicals with a high concentration and oxidation potential can effectively degrade MPs. There is a limited review article to bridge the fate and environmental behaviors of MP with free radicals and their reactions. This paper reviews the sources, types, detection methods, generation mechanisms, and influencing factors of free radicals affecting the environmental processes of MPs, the environmental effects of MPs controlled by free radicals, and the degradation strategies of MPs based on free radical-associated technologies. Moreover, this review elaborates on the limitations of the current research and provides ideas for future research on the interactions between MPs and free radicals to better explain their environmental impacts and control their risks. This article aims to keep the reader abreast of the latest development in the fate and environmental behaviors of MP with free radicals and their reactions and to bridge free radical chemistry with MP control methodology.
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Affiliation(s)
- Ye Qiu
- College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, 38 Tongyan Rd., Tianjin 300350, China; Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macao Special Administrative Region of China
| | - Tong Zhang
- College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, 38 Tongyan Rd., Tianjin 300350, China.
| | - Ping Zhang
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macao Special Administrative Region of China.
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Xia Y, Niu S, Wang T, Wu J. Aging dependent plastic bag derived-microplastics as a vector of metals in lake water. MARINE POLLUTION BULLETIN 2023; 187:114588. [PMID: 36652863 DOI: 10.1016/j.marpolbul.2023.114588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
The adsorption of microplastics (MPs) for metals in aquatic environment remains poorly understood due to the use of either commercial MPs, which have different property from the MPs in environments, or artificial solutions, which have not only the significantly higher concentration of metals than natural aqueous environment but also the different natures. In this study, we elaborated the adsorption throughout the aging process of plastic bag derived-MPs (initially 1-2 mm) by potassium persulfate (K2S2O8) solution to metals in lake water. Comparatively, plastic bag derived-MPs had the highest adsorption capacity for Zn2+ followed by Fe3+, Pb2+, Mn2+, Cr6+, Ni2+, Cu2+ and Cd2+, which is not completely consistent with the literature. Both the adsorption capacity and distribution coefficients of Cu2+, Ni2+, Zn2+, Mn2+ and Pb2+ had significant linear correlation with carbonyl index (p < 0.05). Although the aging overall enhanced the adsorption, the adsorption capacities of MPs might fluctuate depending on metal.
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Affiliation(s)
- Yanrong Xia
- Department of Environmental Science and Engineering, School of Energy and Environment, Anhui University of Technology, Ma'anshan 243002, People's Republic of China
| | - Siping Niu
- Department of Environmental Science and Engineering, School of Energy and Environment, Anhui University of Technology, Ma'anshan 243002, People's Republic of China.
| | - Tiantian Wang
- Department of Environmental Science and Engineering, School of Energy and Environment, Anhui University of Technology, Ma'anshan 243002, People's Republic of China
| | - Jing Wu
- Department of Environmental Science and Engineering, School of Energy and Environment, Anhui University of Technology, Ma'anshan 243002, People's Republic of China
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