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Coprecipitation mechanisms of Zn by birnessite formation and its mineralogy under neutral pH conditions

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Journal of Environmental Sciences 2022年第11期34卷 136-147页

作者： Shota Tajima Shigeshi Fuchida Chiharu Tokoro Graduate School of Creative Science and Engineering Waseda University3-4-1 OkuboShinjuku-kuTokyo 169-8555Japan Faculty of Science and Engineering Waseda University3-4-1 OkuboShinjuku-kuTokyo 169-8555Japan Faculty of Engineering The University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-8656Japan

Birnessite(δ-Mn(IV)O_(2))is a great manganese(Mn)adsorbent for dissolved divalent metals.In this study,we investigated the coprecipitation mechanism of δ-MnO_(2) in the presence of Zn(II)and an oxidizing agent(sodium hypochlorite)under two neutral pH values(6.0 and 7.5).Themineralogical characteristics and Zn–Mn mixed products were compared with simple surface complexation by adsorption modeling and structural analysis.Batch coprecipitation experiments at different Zn/Mn molar ratios showed a Langmuir-type isotherm at pH 6.0,which was similar to the result of adsorption experiments at pH 6.0 and 7.5.X-ray diffraction and X-ray absorption fine structure analysis revealed triple-corner-sharing innersphere complexation on the vacant sites was the dominant Zn sorption mechanism on δ-MnO_(2) under these experimental conditions.A coprecipitation experiment at pH 6.0 produced some hetaerolite(ZnMn(Ⅲ)_(2)O_(4))and manganite(γ-Mn(Ⅲ)OOH),but only at low Zn/Mn molar ratios(surface,and that the pH is an important controlling factor for the crystalline structures and thermodynamic stabilities.

关键词： δ-MnO2 Zinc removal surface complexation X-ray absorption fine structure

Enhanced adsorption and colorimetric detection of tetracycline antibiotics by using functional phosphate/carbonate composite with nanoporous network coverage

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Journal of Environmental Sciences 2023年第4期126卷 365-377页

作者： Pratchayaporn Yukhajon Titikan Somboon Sira Sansuk Materials Chemistry Research Center Department of Chemistry and Center of Excellence for Innovation in ChemistryFaculty of ScienceKhon Kaen UniversityKhon Kaen 40002Thailand Department of Chemistry Faculty of EngineeringRajamangala University of Technology IsanKhon Kaen CampusKhon Kaen 40000Thailand

This work presents efficient tetracycline(TC) antibiotics adsorption using a functional porous phosphate/carbonate composite(PCC). The PCC was fabricated by anion-exchange of phosphate on the surface of vaterite-phase calcium carbonate particle scaffolds. The PCC,having dense nanoporous network coverage with large surface area and pore volume, exhibited excellent TC adsorption in solution. Its adsorption isotherm fitted well to the Freundlich model, with a maximum adsorption capacity of 118.72 mg/g. The adsorption process was spontaneous, endothermic, and followed pseudo-second-order kinetics. From the XPS analysis, the hydrogen bonding and surface complexation were the key interactions in the process. In addition, a colorimetric TC detection method was developed considering its complexation with phosphate ions, originating from PCC dissolution, during adsorption.The method was used to detect TC in mg/L concentrations in water samples. Thus, the multifunctional PCC exhibited potential for use in TC removal and environmental remediation.

关键词： Porous composite Calcium carbonate Tetracycline Adsorption Colorimetric detection surface complexation

The role of organic and inorganic substituents of roxarsone determines its binding behavior and mechanisms onto nano-ferrihydrite colloidal particles

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Journal of Environmental Sciences 2023年第7期129卷 30-44页

作者： Ming Lei Yayuan Huang Yimin Zhou Caleb Oppong Mensah Dongning Wei Bingyu Li College of Resource&Environment Hunan Agricultural UniversityChangsha 410128China Hunan Engineering&Technology Research Center for Irrigation Water Purification Changsha 410128China Key Laboratory of Southern Farmland Pollution Prevention and Control Ministry of AgricultureChangsha 410128China

The retention and fate of Roxarsone(ROX)onto typical reactive soil minerals were crucial for evaluating its potential environmental risk.However,the behavior and molecular-level reaction mechanism of ROX and its substituents with iron(hydr)oxides remains unclear.Herein,the binding behavior of ROX on ferrihydrite(Fh)was investigated through batch experiments and in-situ ATR-FTIR techniques.Our results demonstrated that Fh is an effective geo-sorbent for the retention of ROX.The pseudo-second-order kinetic and the Langmuir model successfully described the sorption process.The driving force for the binding of ROX on Fh was ascribed to the chemical adsorption,and the rate-limiting step is simultaneously dominated by intraparticle and film diffusion.Isotherms results revealed that the sorption of ROX onto Fh appeared in uniformly distributed monolayer adsorption sites.The twodimensional correlation spectroscopy and XPS results implied that the nitro,hydroxyl,and arsenate moiety of ROX molecules have participated in binding ROX onto Fh,signifying that the predominated mechanisms were attributed to the hydrogen bonding and surface complexation.Our results can help to better understand the ROX-mineral interactions at the molecular level and lay the foundation for exploring the degradation,transformation,and remediation technologies of ROX and structural analog pollutants in the environment.

关键词： Ferrihydrite 2D-COS surface complexation Electrostatic interaction Roxarsone

Extraction of rare earth elements from a South American ionic clay

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稀土学报:英文版 2023年第9期41卷 1408-1418,I0005页

作者： John Anawati Gisele Azimi Laboratory for Strategic Materials Department of Chemical Engineering and Applied ChemistryUniversity of Toronto200 College StreetTorontoOntarioM5S3E5Canada Department of Materials Science and Engineering University of Toronto184 College StreetTorontoOntarioM5S 3E4Canada

Ionic clays,formed by the natural weathering of REE-bearing minerals and the adsorption of the resulting liberated REE ions onto the clay surface,are an important resource for critical rare earth elements(REEs).Here,a two-step desorption process using ammonium sulfate with active pH adjustment using sulfuric acid was developed to extract REEs from a South American clay.The desorption process was optimized using response surface methodology approach and the optimum operating conditions were determined to be 0.15 mol/L ammonium sulfate,pH 3,liquid to solid ratio of 3/1,and 25℃ with20 min residence time.It is shown that this ionic clay is significantly different from previously reported clays,e.g.,from southern China,as it consists of three modes of REEs,including ion-exchanged REEs physically adsorbed on the clay surface,hydrolyzed REEs chemically adsorbed on the clay surface,and mineralized(non-desorbable) REEs within the clay.Mechanistic investigations through progressive acidification during desorption and adsorption isotherms show that REE desorption/adsorption occurs due to the combined action of physical ion exchange adsorption and surface complexation chemical adsorption,with their relative importance depending on the pH of the system and the amount of sulfate anions present within the solution.This work supports overall efforts to utilize ionic clays as a relatively new resource for REEs to empower the development and adoption of modern green technologies such as wind turbines and electric vehicles.

关键词： Ionic clay Ion-exchange desorption surface complexation Ammonium sulfate leaching Rare earths

Interactions of organic phosphorus with soil minerals and the associated environmental impacts: A review

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Pedosphere 2023年第1期33卷 74-92页

作者： Yupeng YAN Biao WAN Rui JIANG Xiaoming WANG Hui WANG Shuai LAN Qin ZHANG Xionghan FENG Key Laboratory of Poyang Lake Watershed Agricultural Resources and Ecology of Jiangxi Province College of Land Resources and EnvironmentJiangxi Agricultural UniversityNanchang 330045China Key Laboratory of Arable Land Conservation(Middle and Lower Reaches of Yangtze River) Ministry of Agriculture and Rural AffairsCollege of Resources and EnvironmentHuazhong Agricultural UniversityWuhan 430070China Geomicrobiology Center for Applied GeosciencesUniversity of TuebingenTuebingen 72076Germany Soil and Fertilizer Institute Anhui Academy of Agricultural SciencesHefei 230001China

As an important part of the soil phosphorus(P)pool,organic P(OP)is widely found in terrestrial and aquatic environments(e.g.,soils and sediments).The interfacial behavior of OP on natural minerals affects the transport,transformation,and bioavailability of P in the environment.This paper reviews the processes involving adsorption-desorption,dissolution-precipitation,and enzymatic/mineral-mediated hydrolysis of OP at the mineral-water interface,and their subsequent effects on OP speciation and mineral colloidal stability/reactivity.The sorption mechanisms of OP on natural minerals mainly include surface complexation and precipitation,which are controlled by factors such as mineral identity and crystallinity,the relative molecular weight of OP,reaction pH,ionic strength,temperature,and co-existing ligands or ions.The desorption amount and rate of OP from minerals are determined by the mineral identity,desorbent type,pre-sorption time,OP species,reaction pH,number of desorption cycles,and redox status.The interactions between OP and minerals affect the sorption of co-existing metal ions and the stability of the minerals.The effect of minerals on the enzymatic hydrolysis of OP sorbed on mineral surfaces depends on the mineral identity and OP species.Some minerals also exhibit catalytic activity to promote the cleavage of C–O–P bonds and OP hydrolysis.We provide an overview of state-of-the-art techniques currently applied in environmental OP research.The main challenges and future research directions are also summarized to further explore OP interactions with natural minerals in complex environmental settings.

关键词： hydrolysis interfacial reactions natural minerals sorption surface complexation surface precipitation

Spectroscopic study on variations in illite surface properties after acid-base titration

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Journal of Environmental Sciences 2003年第4期15卷 456-463页

作者： LIUWen-xin COVENEYR.M. TANGHong-xiao SKLEAC ResearchCenterforEco-EnvironmentalSciencesChineseAcademyofSciencesBeijing100085China DepartmentofGeosciences UniversityofMissouri-KansasCity420DRobertH.FlarsheimHall5100HockhillRoadKansasCityMissouri64110-2499)

FT IR, Raman microscopy, XRD, 29 Si and 27 Al MAS NMR, were used to investigate changes in surface properties of a natural illite sample after acid base potentiometric titration. The characteristic XRD lines indicated the presence of surface Al Si complexes, preferable to Al(OH) 3 precipitates. In the microscopic Raman spectra, the vibration peaks of Si O and Al O bonds diminished as a result of treatment with acid, then increased after hydroxide back titration. The varied ratio of signal intensity between IV Al and VI Al species in 27 Al MAS NMR spectra, together with the stable BET surface area after acidimetric titration, suggested that edge faces and basal planes in the layer structure of illite participated in dissolution of structural components. The combined spectroscopic evidence demonstrated that the reactions between illite surfaces and acid leaching silicic acid and aluminum ions should be considered in the model description of surface acid base properties of the aqueous illite.

关键词： natural illite acid base titration spectroscopic information surface Al Si species surface complexation

Two-dimensional correlation spectroscopic analysis on the interaction between humic acids and aluminum coagulant

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Journal of Environmental Sciences 2018年第2期30卷 181-189页

作者： Pengkang Jin Jina Song Xiaochang C.Wang Xin Jin School of Environmental and Municipal Engineering Xi'an University of Architecture and Technology College of Energy and Environmental Engineering Hebei University of Engineering

In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagulant at slightly acidic and neutral p H. Higher fluorescence quenching was produced for fulvic-like and humic-like fractions at p H 5. At p H 5, the humic-like fractions originating from the carboxylic acid, carboxyl and polysaccharide compounds were bound to aluminum first, followed by the fulvic-like fractions originating from the carboxyl and polysaccharide compounds. This finding also demonstrated that the activated functional groups of HA were involved in forming the Al-HA complex, which was accompanied by the removal of other groups by co-precipitation.Meanwhile, at p H 7, almost no fluorescence quenching occurred, and surface complexation was observed to occur, in which the activated functional groups were absorbed on the amorphous Al（OH）3. Two-dimensional FT-IR correlation spectroscopy indicated the sequence of HA structural change during coagulation with aluminum, with IR bands affected in the order of COOH〉 COO-〉NH deformation of amide Ⅱ〉 aliphatic hydroxyl C／OH at p H 5, and COO-〉aliphatic hydroxyl C／OH at p H 7. This study provides a promising pathway for analysis and insight into the priority of functional groups in the interaction between organic matters and metal coagulants.

关键词： Two-dimensional correlation spectroscopy Al-HA complex surface complexation Interaction sequence

Impact of crystalline and amorphous iron-and aluminum hydroxides on mechanisms of phosphate adsorption and desorption

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Journal of Environmental Sciences 2018年第8期30卷 175-189页

作者： Stella Gypser Florian Hirsch Anja M.Schleicher Dirk Freese Brandenburg University of Technology Cottbus-Senftenberg Faculty of Environment Process Engineering Biotechnology and Chemistry Department of Soil Protection and Recultivation Brandenburg University of Technology Cottbus-Senftenberg Faculty of Environment Process Engineering Biotechnology and Chemistry Department of Geopedology and Landscape Development German Research Centre for Geosciences Section 3.1 Inorganic and Isotope Geochchemistry

Fourier-transform infrared（FT-IR） spectroscopic experiments were carried out during phosphate adsorption on highly crystalline gibbsite, poorly crystalline 2-line-ferrihydrite and amorphous iron–aluminum–hydroxide mixtures in the molar ratio 1：0, 10：1, 5：1, 1：1, 1：5, 1：10 and 0：1. The OH stretching vibrational bands were utilized to analyze changes in structural and surface OH groups during adsorption, because the position of characteristic P／O vibrational bands can shift depending on reaction conditions, pH or adsorbed phosphate content.Adsorption and desorption kinetics were studied at pH6 and different initial phosphate concentrations to achieve varying phosphate coverage on the mineral surfaces. For gibbsite the formation of AlHPO4 and Al2HPO4 can be assumed, while for ferrihydrite, a FeHPO4 or Fe2PO4 complex and the precipitation of FePO4 with longer equilibration time were proposed.Fe2HPO4 or a Fe2PO4 surface complex was deduced for Fe-hydroxides, an AlH2PO4 surface complex was identified for Al-hydroxide, and both displayed either hydrogen bonds to neighboring hydroxyl groups or hydrogen bonds to outer-sphere complexes. Fe：Al-hydroxide mixtures with high Al ratios showed a low phosphate desorption rate, while ferrihydrite and the Fe：Al-hydroxide mixtures with high Fe ratios had almost negligible desorption rates. It was concluded that within the weakly associated amorphous FeO（OH） materials, FePO4 precipitated, which was bound by outer-sphere hydrogen bonds. With high Al ratios, desorption increased, which indicated weaker phosphate binding of both inner-sphere and outer-sphere complexes and hence, either no or minor quantities of precipitate. Ferrihydrite showed a more rigid structure and a lower extent of precipitation compared to amorphous Fe-hydroxide.

关键词： Phosphate Adsorption Desorption surface complexation Precipitation FT-IR

Intrinsic surface Reaction Constant in 1-pK Model of Mg-Fe Hydrotalcite-like Compounds

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Chinese Journal of Chemistry 2004年第3期22卷 268-270页

作者：侯万国韩书华李东祥张高勇 Key Laboratory of Colloid and Interface Chemistry (Shandong University) Ministry of Education Jinan Shandong 250100 China Key Laboratory of Colloid and Interface Chemistry (Shandong University) Ministry of Education Jinan Shandong 250100 China China Research Institute of Daily Chemical Industry Taiyuan Shanxi 030001 China

The relationship among intrinsic surface reaction constant (K) in 1-pK model, point of zero net charge (PZNC) and structural charge density (st) for amphoteric solid with structural charges was established in order to investigate the effect of st on pK. The theoretical analysis based on 1-pK model indicates that the independent PZNC of electrolyte concentration (c) exists for amphoteric solid with structural charges. A common intersection point (CIP) should appear on the acid-base titration curves at different c, and the pH at the CIP is pHPZNC. The pK can be expressed as pK=-pHPZNC+log[(1+2aPZNC)/(1-2aPZNC)], where aPZNC≡st/eNANs, in which e is the elementary charge, NA the Avogadro抯 constant and Ns the total density of surface sites. For solids without structural charges, pK=-pHPZNC. The pK values of hydrotalcite-like compounds (HTlc) with general formula of [Mg1-xFex(OH)2](Cl, OH)x were evaluated. With increasing x, the pK increases, which can be explained based on the affinity of metal cations for H+ or OH- and the electrostatic interaction between charging surface and H+ or OH-.

关键词： surface complexation electric double layer points of zero charge acid-base chemistry structurally charged material