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An insight into aggregation kinetics of polystyrene nanoplastics interaction with metal cations

Chinese Chemical Letters 2022年第12期33卷 5213-5217页

作者： Yucheng Zhang Xiaotong Su Nora FYTam Xiaolan Lao Meiling Zhong Qihang Wu Huifang Lei Zihui Chen Zhang Li Jie Fu Key Laboratory for Water Quality and Conservation of the Pearl Stream Delta Ministry of EducationSchool of Environmental Science and EngineeringGuangzhou UniversityGuangzhou 510006China State Key Laboratory of Marine Pollution and Department of Chemistry City University of Hong KongHong KongChina School of Science and Technology Open University of Hong KongHong KongChina School of Environmental Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

Once inevitably released into the aquatic environment,polystyrene nanoplastics(PS-NPs)will present complicated environmental behaviors,of which the aggregation is a key process determining their environmental fate and impact.In this study,the aggregation kinetics of different sizes(30 nm and 100 nm)of PS-NPs with metal cations(Na^(+),K^(+),Ca^(2+),Mg^(2+)and Pb^(2+))at different solution pH(3,6 and 8)were investigated.The results showed that the aggregation of PS-NPs increased with cation concentration.Taking Pb^(2+)as an example,the adsorption behavior of cations onto PS-NPs was determined by transmission electron microscopy(TEM)and energy dispersive X-ray(EDX)spectroscopy,which demonstrated Pb^(2+)could be adhered onto the surface of PS-NPs with the effect of charge neutralization.The critical coagulation concentrations(CCC)of smaller PS-NPs were higher than that of larger PS-NPs for monovalent cations,whereas a different pattern is observed for divalent cations.It was suggested that there were other factors that DLVO theory does not consider affect the stability of NPs with different particle sizes.In addition,it should be noted that PS-NPs had the capacity of adsorbing large amounts of heavy metal cations and carried them transport to a long distance,and the corresponding ecological risks need to further elucidate.

关键词： Polystyrene nanoplastics Lead cation aggregation kinetics Critical coagulation concentration Size effect

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Influence of extracellular polymeric substances from activated sludge on the aggregation kinetics of silver and silver sulfide nanoparticles

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Frontiers of Environmental Science & Engineering 2022年第2期16卷 13-24页

作者： Wanpeng Chen Jiahui Song Shaojie Jiang Qiang He Jun Ma Xiaoliu Huangfu Key Laboratory of Eco-environments in Three Gorges Reservoir Region(Ministry of Education) College of Environment and EcologyChongqing UniversityChongqing 400044China Sichuan Education Press Chengdu 610200China State Key Laboratory of Urban Water Resource and Environment School of Municipal and Environmental EngineeringHarbin Institute of TechnologyHarbin 150090China

Extracellular polymeric substances(EPS)in activated sludge from wastewater treatment plants(WWTPs)could affect interactions between nanoparticles and alter their migration behavior.The influence mechanisms of silver nanoparticles(Ag NPs)and silver sulfide nanoparticles(Ag_(2)S NPs)aggregated by active EPS sludge were studied in monovalent or divalent cation solutions.The aggregation behaviors of the NPs without EPS followed the Derjaguin-Landau-Verwey-Overbeek(DLVO)theory.The counterions aggravated the aggregation of both NPs,and the divalent cation had a strong neutralizing effect due to the decrease in electrostatic repulsive force.Through extended DLVO(EDLVO)model analysis,in NaNO3 and low-concentration Ca(NO_(3))_(2)(aggregation behaviors of Cit-Ag NPs and Ag_(2)S NPs due to the enhancement of steric repulsive forces.At high concentrations of Ca(NO_(3))_(2)(10‒100 mmol/L),exopolysaccharide macromolecules could promote the aggregation of Cit-Ag NPs and Ag_(2)S NPs by interparticle bridging.As the final transformation form of Ag NPs in water environments,Ag_(2)S NPs had better stability,possibly due to their small van der Waals forces and their strong steric repulsive forces.It is essential to elucidate the surface mechanisms between EPS and NPs to understand the different fates of metal-based and metal-sulfide NPs in WWTP systems.

关键词： Silver nanoparticles Silver sulfide nanoparticles Extracellular polymeric substances aggregation kinetics Influence mechanisms

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The aggregation kinetics of Colloidal Particles of Basic Yttrium Carbonate

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Chinese Chemical Letters 1998年第12期9卷 0-0,0-0页

作者： Hui WANG Zun Sheng CAI Yin Ming PAN Xue Zhuang ZHAO(Department of Chemistry,)Ying Li AN (The State Key Laboratory of Functional Polymer Meterials for Absorption and Separation,)Shi Yi GUO (The Electron Microscope Labrotory of College of Life ScienceNa Department of Chemistry Nankai University Tianjin 300071 China State Key Lab. Funct. Poly. M.A./S. Nankai University Tianjin 300071 China Electron Microscope Labrotory College of Life Science Nankai University Tianjin 300071 China

The aggregation kinetics of basic yttrium carbonate pericles in aqueous solution havebeen studied using dynamic light-scattering techniques. In 1.00mol/l NaCl solution fast diffusionlimited aggregation behavior was observed with an increase in aggregate size over time describedby a power law. The aggregates are characterized by a fractal dimension D=1.82. Smoluchowskiand fractal theories were used to characterize the aggregation mechanism and to obtain theaggregation rate constant.

关键词： Basic yttrium carbonate fractal aggregate aggregation kinetics

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Formation and aggregation kinetics of Mixed Metal Hydroxides Agglomerates

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Chinese Chemical Letters 2005年第6期16卷 835-838页

作者： ZhiLinJIN WanGuoHOU XueWeiLI DeJunSUN ChunGuangZHANG KeyLaboratoryforColloid＆InterfaceChemistryofEducationMinistry ShandongUniversityJinan250100 TheCenterforSoftwareResearchandDevelopment TianjinUniversityTianjin300072

The aggregation and fractal structure of mixed metal hydroxides (MMH) agglomerates with increasing ionic strength have been studied by dynamic light scattering (DLS) and SEM techniques. The experiments indicate that the MMH agglomerates have two different structures in RLA regime and DLA regime, and also give the proof that the transition region between RLA and DLA may occur.

关键词： aggregation kinetics fractal structure the mixed metal hydroxides ( MMH ).

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Effects of humic acid and surfactants on the aggregation kinetics of manganese dioxide colloids

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Frontiers of Environmental Science & Engineering 2015年第1期9卷 105-111页

作者： Xiaoliu HUANGFU Yaan WANG Yongze LIU Xixin LU Xiang ZHANG Haijun CHENG Jin JIANG Jun MA Key Laboratory of Urban Water Resource and Environment School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China

The aggregation of common manganese diox- ide （MnO2） colloids has great impact on their surface reactivity and therefore on their fates as well as associated natural and synthetic contaminants in engineered （e.g. water treatment） and natural aquatic environments. Nevertheless, little is known about the aggregation kinetics of MnO2 colloids and the effect of humic acid （HA） and surfactants on these. In this study, the early stage aggregation kinetics of MnO2 nanoparticles in NaNO3 and Ca（NO3）2 solutions in the presence of HA and surfactants （i.e., sodium dodecyl sulfate （SDS）, and polyvinylpyrrolidone （PVP）） were modeled through time-resolved dynamic light scattering. In the presence of HA, MnO2 colloids were significantly stabilized with a critical coagulation concentration （CCC） of-300mmol · L-1 NaNO3 and 4 mmol.L-1 Ca（NO3）2. Electrophoretic mobility （EPM） measurements confirmed that steric hindrance may be primarily responsible for increasing colloidal stability in the presence of HA. Moreover, the molecular and/or chemical properties of HA might impact its stabilizing efficiency. In the case of PVP, only a slight increase of aggregation kinetics was observed, due to steric reactions originating from adsorbed layers of PVP on the MnO2 surface. Consequently, higher CCC values were obtained in the presence of PVP. However, there was a negligible reduction in MnO2 colloidal stability in the presence of 20 mg·L-1SDS.

关键词： manganese dioxide colloids humic acid,surfactant aggregation kinetics drinking water

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Effects of low molecular weight organic acids on aggregation behavior of biochar colloids at acid and neutral conditions

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Biochar 2022年第1期4卷 852-863页

作者： Yang Wang Changxi Wang Jiayi Xiong Qianru Zhang Jianying Shang College of Land Science and Technology China Agricultural UniversityKey Laboratory of Plant-Soil InteractionsMinistry of EducationKey Laboratory of Arable Land Conservation(North China)Ministry of AgricultureBeijing 100193China Key Laboratory of Nonpoint Source Pollution Control Ministry of Agriculture and Rural AffairsInstitute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China

Low molecular weight organic acids(LMWOAs),as active components in the rhizosphere carbon cycling,may influence the environmental behaviors of biochar colloids.This study selected the pine-wood and wheat-straw biochars(PB and WB)as two typical biochars.The effects of typical LMWOAs(oxalic acid,citric acid,and malic acid)on aggregation kinetics of PB and WB colloids were investigated under pH 4 and 6 conditions.Critical coagulation concentrations(CCCs)of both PB and WB colloids were decreased with the LMWOAs regardless of the types of biochar and the solution pH,and the most significant effect occurred in pH 4 due to more LMWOAs sorption on the biochar colloids.The different types of LMWOAs caused various CCCs changes.For example,the CCC values of PB colloids decreased from 75 mM to 56,52,and 47 mM in the pH 4 NaCl solutions when 1 mM oxalic acid,citric acid,and malic acid were present in the suspensions,respectively.The chemical structure(functional groups)and molecular weight of LMWOAs,solution pH,and the electrophoretic mobility(EPM)of biochar co-influence the interactions between biochar colloids and LMWOAs,thus affecting the stability of biochar colloids in the presence of LMWOAs.The presence of LMWOAs accelerated the aggregation of colloidal biochar by increasing the interaction of surface bridging bonds(hydrogen bonding)and decreasing the repulsive force between colloidal biochar particles.This study showed that LMWOAs could accelerate the aggregation of biochar colloids in acidic or neutral environments and reduce the mobility of biochar colloids in soil rhizosphere.

关键词： Biochar colloids aggregation kinetics Low molecular weight organic acids(LMWOAs) Critical coagulation concentrations(CCCs)

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Biochemical and biophysical characterization of pathological aggregation of amyloid proteins

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Biophysics Reports 2022年第1期8卷 42-54页

作者： Houfang Long Shuyi Zeng Yunpeng Sun Cong Liu Interdisciplinary Research Center on Biology and Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Bio-X Institutes Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders Ministry of Education Shanghai Jiao Tong University University of Chinese Academy of Sciences Bio-X-Renji Hospital Research Center Renji Hospital School of Medicine Shanghai Jiao Tong University

Protein amyloid fibrillation, a process of liquid to solid phase transition, is involved in the pathogenesis of a variety of human diseases. Several amyloid proteins including α-synuclein(α-syn), Tau, amyloid β(Aβ) protein, and TAR DNA-binding protein 43 k Da(TDP-43) form pathological fibrils and deposit in patient brains of different neurodegenerative diseases(NDs) such as Parkinson’s disease(PD),Alzheimer’s disease(AD) and Amyotrophic lateral sclerosis(ALS). Preparation and characterization of amyloid fibrils in vitro are essential for studying the molecular mechanism underlying the dynamic amyloid aggregation and its pathogenesis in diseases. In this protocol, we take PD-associated α-syn as an example, and describe amyloid protein purification and fibrillation approaches. We then introduce biochemical and biophysical characterization of amyloid fibrils by Thioflavin-T(Th T) fluorescence kinetics assay, transmission electron microscopy(TEM), atomic force microscopy(AFM) and multiple fibril stability measurement assays. The approaches described here are applicable to different amyloid proteins, and are of importance for further study on the structure determination of amyloid fibrils and their pathological function in cells and animal models.

关键词： Amyloid protein Pathological fibrillation Transmission electron microscopy α-Synuclein aggregation kinetics Neurodegenerative diseases Parkinson’s disease

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