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Frontiers of Environmental Science & Engineering 2019年第4期13卷 45-55页

作者： Xiaomeng Wang Ning Li Jianye Li Junjun Feng Zhun Ma Yuting Xu Yongchao Sun Dongmei Xu Jian Wang Xueli Gao Jun Gao College of Chemical and Environmental Engineering Shandong University of Science and TechnologyQingdao 266590China School of Chemical and Environmental Engineering Weifang University of Science & TechnologyShouguang 262700China Key Laboratory of Marine Chemistry Theory and Technology(Ministry of Education)/College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China The Institute of Seawater Desalination and Multipurpose Utilization SOATianjin 300192China

Response surface methodology was utilized to model and optimize the operational variables for defluoridation using an electrodialysis process as the treatment of secondary effluent of the graphite industry. Experiments were conducted using a Box-Behnken surface statistical design in order to evaluate the effects and the interaction of the influential variables including the operational voltage, initial fluoride concentration and flow rate. The regression models for defluoridation and energy consumption responses were statistically validated using analysis of variance (ANOVA);high coefficient of determination values (R^2 = 0.9772 and R^2 = 0.9814;respectively) were obtained. The quadratic model exhibited high reproducibility and a good fit of the experimental data. The optimum values of the initial fluoride concentration, voltage and flow rate were found to be 13.9 mg/L, 13.4 V, 102.5 L/h, respectively. A fluoride removal efficiency of 99.69% was observed under optimum conditions for the treatment of the secondary effluent of the graphite industry.

关键词： Response surface methodology fluoride removal Electrodialysis Box-Behnken design

fluoride removal from coal mining water using novel polymeric aluminum modified activated carbon prepared through mechanochemical process

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Journal of Environmental Sciences 2024年第12期146卷 226-236页

作者： Yixiang Bao Yonghui Qi Qiao Li Lei Wang Zhiguo Cao Jie Li Min Wu Jun Chen Haiqin Zhang Qiang Guo Binbin Jiang Jinkui Zhong Jingfeng Li State Key Laboratory of Water Resource Protection and Utilization in Coal Mining National Institute of Clean and Low Carbon EnergyBeijing 102209China School of Environmental and Municipal Engineering Lanzhou Jiaotong UniversityLanzhou 730070China China Coal Society Chaoyang DistrictBeijing 100013China Guoneng Shendong Coal Technology Research Institute Yulin 719315China Bulianta Coal Mine Shendong Coal Group Co.Ltd.Erdos 017209China

Defluoridation of coal mining water is of great significance for sustainable development of coal industry in western China.A novel one-step mechanochemical method was developed to prepare polymeric aluminum modified powder activated carbon(PAC)for effective fluoride removal from coal mining *** was stably loaded on the PAC through facile solid-phase reaction between polymeric aluminum(polyaluminum chloride(PACl)or polyaluminum ferric chloride(PAFC))and PAC(1:15 W/W).fluoride adsorption on PACl and PAFC modified PAC(C-PACl and C-PAFC)all reached equilibrium within 5 min,at rate of 2.56 g mg^(-1)sec^(-1)and 1.31 g mg^(-1)sec^(-1)*** increase of binding energy of Al on C-PACl(Al–F bond:76.64 eV and Al–FOH bond:77.70 eV)relative to that of Al on C-PAFC(Al–F bond:76.52 eV)explained higher fluoride uptake capacity of *** chloride was released from C-PACl than that from C-PAFC due to its higher proportion of covalent chlorine and lower proportion of ionic *** elements mapping and atomic composition proved the stability of Al loaded on the PAC as well as the enrichment of fluoride on both CPACl and *** Bader charge,formation energy and bond length obtained from DFT computational results explained the fluoride adsorption mechanism *** carbon emission was 7.73 kg CO_(2)-eq/kg adsorbent prepared through mechanochemical process,which was as low as 1:82.3 to 1:8.07×10^(4)compared with the ones prepared by conventional hydrothermal methods.

关键词： fluoride Adsorption Mechanochemistry Polymeric aluminum Powder activated carbon

Distribution of Aluminum and fluoride in Tea Plant and Soil of Tea Garden in Central and Southwest China

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Chinese Geographical Science 2007年第4期17卷 376-382页

作者： XIE Zhonglei CHEN Zhuo SUN Wentian GUO Xiaojing YIN Bo WANG Jinghua College of Environment and Resources Jilin University Changchun 130012 China

The distribution of Al and F contents and the relationship between Al and F in tea plants and soils of 12 tea gardens in Central and Southwest China were investigated from October 31 to November 14, 2006. The results show that there were differences in pH, CEC, the contents of organic matter （OM）, Al and F in the different soils of the tea gardens. The Al content ranged from 1196 to 7976mg/kg for old leaf, 370 to 2681mg/kg for young leaf and 285 to 525mg/kg for stem, whereas the content of F ranged from 221 to 1504mg/kg for old leaf, 49 to 602mg/kg for young leaf and 13.5 to 77.5mg/kg for stem. The concentrations of labile Al varied obviously in the different soils, but the distribution law of labile Al content for the same garden was Alexchangeable≈*** oxide〉Alorganic〉***. The contents of different labile F fractions varied slightly in the different soils and the different soil layers, though the exchangeable F content was lowest among the labile F in the soils. The concentrations of Al and F in tea plants increased with increasing amount of water-soluble Al or F, especially the amount of water-soluble fractions in the soil layer of 0-20cm. The correlation between Al content and F content in the tea leaf was more significant than that in the tea stem. Furthermore, the correlation between Al content and F content in whole tea plant was strongly significant （r=0.8763, p〈0.01, n=36）. There were evident tendency that Al concentration increased with the increase of F concentration in different soil layers. The correlation of water-soluble Al with water-soluble F in all soils was also strongly significant （r=0.7029, p〈0.01, n=34）. The results may provide a proof that Al and F are jointly taken up by tea plants to some extent in natural tea gardens.

关键词： tea garden soil tea plant aluminum fluoride

fluoride contamination in groundwater:A global review of the status,processes,challenges,and remedial measures

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Geoscience Frontiers 2024年第2期15卷 1-29页

作者： E.Shaji K.V.Sarath M.Santosh P.K.Krishnaprasad B.K.Arya Manisha S.Babu Department of Geology University of KeralaKariavattom CampusThiruvananthapuramKerala 695581India School of Earth Sciences and Resources China University of Geosciences(Beijing)29 Xueyuan RoadBeijing 100083China Department of Earth Science University of AdelaideAdelaideSA 5005Australia Department of Geology Central University of KeralaTejaswini HillsPeriyeKasaragodKerala 671316India

Groundwater pollution by fluoride is one of the prime concerns of the world population due to its toxicity,which results in adverse health *** this paper,we review the current scenario of the fluoride contamination of groundwater in various countries across the globe and its impact on human *** the last decade,several newly affected regions have been reported all over the world,with more than 100 countries affected by fluoride contamination in groundwater(concentration exceeding the acceptable limit of 1.5 mg/L defined by the World Health Organization).fluoride poisoning is mainly due to the unsupervised ingestion of products for dental and oral hygiene and over-fluoridated drinking *** is estimated that more than 200 million people from different countries are affected by fluoriderelated groundwater issues and health *** highest among these are from the countries in Africa(38),Asia(28),and Europe(24),followed by countries like South America(5),North America(3),and Australia(2).The source of fluoride in drinking water is primarily geogenic,together with forage,grasses and grains,tea,and anthropogenic *** countries affected were correlated with climatic zones and geological factors to gain insights into geospatial *** analyses show that most of the fluoride pollution-prone zones are located in high-grade metamorphic terranes with granitoid or alkaline intrusions,geothermal hot springs,and volcanic regions with arid or semi-arid climatic *** study also finds that children across the globe are more vulnerable than adults to fluoride *** review finds that,although there are efficient fluoride removal techniques,including filters with next-generation nanomaterials,to date,there has not been a single technique developed that can claim to be a practically robust solution for fluoride removal from drinking ***,we suggest developing next-generation filters that can retain essential miner

关键词： fluoride Groundwater Water contamination WHO standards Climate zones Remediation Sustainable Development Goals

fluoride ions in groundwater of the Turkana County, Kenya, East Africa

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Acta Geochimica 2021年第6期40卷 945-960页

作者： Piotr Rusiniak Klaudia Sekuła Ondra Sracek Piotr Stopa Department of Hydrogeology and Engineering Geology Faculty of GeologyGeophysics and Environmental ProtectionAGH University of Science and TechnologyMickiewicza 30 Av30-059 KrakòwPoland Department of Geology Faculty of SciencePalacky University Olomouc17.listopadu 1277146 OlomoucCzech Republic

Groundwater samples were evaluated throughout Turkana County(Kenya,East Africa)while looking for drinking water *** samples showed high concentrations of fluoride with values in the range of 0.15–5.87 mg/*** 50%of the samples exceeded the WHO and Kenyan potable water standard guideline value of 1.5 mg/L for drinking water *** hydrogeochemical studies revealed that the dominant cation in water is Na^(+)and the dominant anion is HCO_(3)^(-)resulting in Na-HCO_(3) type of groundwater,followed by Ca/Mg-HCO_(3) or Na-SO_(4) and Na-Cl in a few *** modelling revealed that the groundwater is undersaturated with respect to gypsum and anhydrite,mostly undersaturated with respect to fluorite(6 samples are at equilibrium),and supersaturated or at equilibrium with respect to calcite(CaCO_(3)).Precipitation of calcite favours the dissolution of F-rich minerals in the alkaline ***,groundwater is enriched with sodium and bicarbonate,probably as a result of chemical weathering of *** groundwater can be presumably used for drinking purposes from 17 wells,but a detailed investigation of other trace element concentrations is necessary.

关键词： Africa Kenya fluoride Groundwater Drinking water Speciation calculation

fluoride-assisted synthesis of anatase TiO_2 nanocrystals with tunable shape and band gap via a solvothermal approach

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Chinese Chemical Letters 2016年第12期27卷 1801-1804页

作者： Zhe-Ming Liu Lan Peng Ai-Wei Tang Department of Chemistry School of Science Beijing Jiaotong University

A simple solvothermal approach employing oleic acid has been developed to prepare anatase TiO2 nanocrystals with different shapes, which were tuned from nanorods to nano-ellipsoids by increasing the amount of NaF from 0 to 0.5 retool, and the optical band gap decreased from 3.47 eV to 3.29 eV accordingly. However, when the fluoride was changed to NH4F, the resultant TiO2 nanocrystals possessed an anatase phase but were made up of smaller-sized nanocrystals and nanorods, and the band gap was increased to 3.53 eV. The X-ray photoelectron spectroscopy （XPS） results illustrated an increase of fluorine content with an increasing amount of NaF could account for the variation of the shape and optical band gap of TiO2 nanocrystals. Moreover, the absence of fluorine content brought about less change of shape and increase of optical band gap of the product synthesized in the presence of NH4F. This result may offer another way to alter the shape and band gap of metal oxide nanocrystals with the assistance of fluoride.

关键词： Anatase TiO2 fluoride Synthesis Optical band gap Solvothermal approach

Residual fluoride self-activated effect enabling upgraded utilization of recycled graphite anode

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Journal of Energy Chemistry 2024年第6期93卷 24-31,I0002页

作者： Shuzhe Yang Qingqing Gao Yukun Li Hongwei Cai Xiaodan Li Gaoxing Sun Shuxin Zhuang Yujin Tong Hao Luo Mi Lu School of Materials Science and Engineering Xiamen University of TechnologyXiamen 361024FujianChina Faculty of Physics University of Duisburg-EssenDuisburg D-47057Germany

Recycling graphite anode from spent lithium-ion batteries(SLIBs)is regarded as a crucial approach to promoting sustainable energy storage ***,the recycled graphite(RG)generally presents degraded structure and ***,the residual fluoride self-activated effect is proposed for the upgraded utilization of *** and low-energy water immersion treatment not only widens the interlayer spacing,but also retains appropriate fluoride on the surface of *** analysis and experiments demonstrate that the residual fluoride can optimize Li~+migration and deposition kinetics,resulting in better Li~+intercalation/deintercalation in the interlayer and more stable Li metal plating/stripping on the surface of RG,As a result,the designed LFP||RG full cells achieve ultrahigh reversibility(~100%Coulombic efficiency),high capacity retention(67%after 200 cycles,0.85 N/P ratio),and commendable adaptability(stable cycling without short-circuiting,0.15 N/P ratio).The energy density is improved from 334 Wh kg^(-1)of 1.1 N/P ratio to 367 Wh kg^(-1)of 0.85 N/P ratio(total mass based on cathode and anode).The exploration of RG by residual fluoride self-activated effect achieves upgraded utilization beyond fresh commercial graphite and highlights a new strategy for efficient reuse of SLIBs.

关键词： Spent lithium-ion batteries Recycled graphite anode fluoride Self-activated effect Upgraded utilization

Mechanism of aluminum complexation in oxidative activity of leaching bacteria in a fluoride-containing bioleaching system

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Rare Metals 2019年第1期38卷 87-94页

作者： Xiang Li Jian-Kang Wen Xiao-Lan Mo Wu Biao Dian-Zuo Wang Hong-Ying Yang National Engineering Laboratory of Biohydrometallurgy General Research Institute for Nonferrous Metals School of Metallurgy Northeastern University

Accumulation of toxic ions in leachate is one factor limiting bioleaching applications. The effect of fluoride ions on the growth of bioleaching microorganisms has been extensively emphasized. In this study, HF is found to be the toxic form of fluoride that affects the bacterial activity under acidic conditions. The added aluminum could compete with H^+ to complex with F-, thus significantly decrease the concentration of HF and finally reduce the toxicity of fluoride to bacteria. When F^-/Al^(3+)concentration ratio is 0.5:1.0, Fe^(2+) oxidation rate could reach 0.167 g·L^(-1)·h^(-1), close to that of the biotic control group(0.195 g·L^(-1)·h^(-1)). The competitive complexation mechanism of fluoride by AlF_n^(3-n) results in stability constants of AlF_n^(3-n) complex(7.00) that are larger than those of HF(3.18). The F^-/Al^(3+) concentration ratio in the medium could affect the speciation of AlF_n^(3-n) *** the decrease in F^-/Al^(3+) concentration ratio, the coordination numbers of AlF_n^(3-n) decrease. Finally, the feasibility of fluoride detoxification by aluminum ion is verified. This work has meaningful implications for fluoride-containing bacterial bioleaching systems.

关键词： Competitive complexation Detoxification fluoride Aluminum Bioleaching

Immobilization and leaching characteristics of fluoride from phosphogypsumbased cemented paste backfill

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International Journal of Minerals,Metallurgy and Materials 2021年第9期28卷 1440-1452页

作者： Qiu-song Chen Shi-yuan Sun Yi-kai Liu Chong-chong Qi Hui-bo Zhou Qin-li Zhang School of Resources and Safety Engineering Central South UniversityChangsha 410083China Department of Geosciences University of PadovaPadova 35131Italy

Phosphogypsum(PG)is a typical by-product of phosphoric acid and phosphate fertilizers during acid *** application of cemented paste backfill(CPB)has been feasibly investigated for the remediation of *** present study evaluated fluorine immobilization mechanisms and attempted to construct a related thermodynamic and geochemical modeling to describe the related stabilization ***-chemical and mineralogical analyses were performed on PG and hardened PG-based CPB(PCPB).The correlated macro-and micro-structural properties were obtained from the analysis of the combination of unconfined compressive strength and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy ***/base-dependent leaching tests were performed to ascertain fluoride *** addition,Gibbs Energy Minimization Software and PHREEQC were applied as tools to characterize the PCPB hydration and deduce its geochemical *** results proved that multiple factors are involved in fluorine stabilization,among which the calcium silicate hy-drate gel was found to be associated with *** the quantitative comparison with the experimental data shows that further modi-fication should be introduced into the simulation before being used as a predictive implement to determine PG management options,the im-portance of acid/base concentration in regulating the leaching behavior was ***,the modeling enabled the identification of the impurity phases controlling the stability and leachability.

关键词： cemented paste backfill phosphogypsum leaching behavior fluoride

Characteristics and model studies for fluoride and arsenic adsorption on goethite

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Journal of Environmental Sciences 2010年第11期22卷 1689-1694页

作者： Yulin Tang Jianmin Wang Naiyun Gao State Key Laboratory of PoUution Control and Resources Reuse College of Environmental Science and Engineering Tongji University Shanghai 200092 China. Department of Civil Architectural & Environmental Engineering Missouri University of Science and Technology Rolla MO 65409 USA

fluoride and arsenic are major anionic elements of concern in drinking water treatment. The effects of contact time, pH, surface loading and ionic strength on adsorption of fluoride and As（V） were investigated using batch methods. Adsorption of fluoride and As（V） onto goethite obeyed a pseudo second-order rate law. Through experimental data and adsorption kinetic analysis, the affinity of As（V） onto goethite was stronger than fluoride. fluoride and As（V） uptake by goethite all decreased with pH increasing at the same surface loading; however, ionic strength had slight influence on their adsorption. A surface sites-species model was used to quantify the adsorption of fluoride and As（V） onto goethite as function of pH and surface loading. This model can satisfactorily predict their adsorption characteristics with several adsorption constants.

关键词： adsorption fluoride arsenic goethite