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Rheological properties of rare earth minerals flotation pulp in the presence of anions

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Journal of Rare Earths 2024年第11期42卷 2172-2182,I0007页

作者： Moonchul Jung Bogale Tadesse Craig Dick Alex Logan Laurence Dyer Boris Albijanic Western Australia School of Mines Curtin UniversityKalgoorlieWA 6430Australia Lynas Rare Earths Ltd Mt Weld Elora RoadLavertonWA 6440Australia

Water quality has been found to significantly influence the flotation operations due to the alteration of surface properties of *** effect of cations on the flotation of RE minerals has been studied,however,there are still very limited information regarding the effect of *** present study examined the impact of specific anions such as Cl^(-),SO_(4)^(2-),and HCO_(3)^(-)on the flotation performance of rare earth(RE) *** study integrates flotation experiments,rheology measurements,entrainment experiments,zeta potential measurements and settling *** is observed that an increase in the concentration of these anions lead to a decrease in the recovery of RE minerals and an increase in the recovery of FeO minerals and thus negatively affecting flotation *** adverse effect is most pronounced with Cl^(-)and least noticeable with HCO_(3)^(-).An increase in the non-selective entrainment of gangue minerals is observed when the flotation pulp has higher *** reduction in the zeta potential of fine particles in the presence of these results in a higher pulp viscosity due to increased attractive forces between *** findings were verified by settling experiments and calculations based on the DLVO theory.

关键词： Flotation Rare earth ore anions Pulp rheology Entrainment DLVO theory

The effect of various cations/anions for MgH_(2) hydrolysis reaction

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Journal of Materials Science & Technology 2021年第14期73卷 186-192页

作者： Chongyang Yuan Wei Chen Zunxian Yang Zhenguo Huang Xuebin Yu Department of Materials Science Fudan UniversityShanghai200433China National and Local United Engineering Laboratory of Flat Panel Display Technology Fuzhou UniversityFuzhou350002FujianChina School of Civil&Environmental Engineering University of Technology SydneyNew South Wales2007Australia

MgH_(2) is regarded as a potential hydrolysis material for the hydrogen generation due to its high theoretical hydrogen yield,abundant source on earth and environmentally friendly ***,the quickly formed passive magnesium hydroxide layer on the surface of MgH_(2) will hinder its further hydrolysis reaction,leading to sluggish reaction kinetics and low H_(2) *** this paper,we explore the improvement of different anions and cations in solutions for the hydrolysis of MgH_(2).It is found that the cations in the solution promote the reaction rate of MgH_(2) hydrolysis through the hydrolysate-induced growth effect,among which the fastest hydrogen yield can get 1664 m L/g within a few minutes in the Fe_(2)(SO_(4))_(3) *** for the anions,it enables different microstructures of the Mg(OH)_(2) hydrolysate which give rise to enhanced water ***,for the mixed 0.5 M MgCl_(2)+0.05 M MgSO_(4) solution,the water utilization rate attains the optimum value of 51.3%,much higher than that of the single MgCl_(2) or MgSO_(4) *** findings are of great significance for the application of MgH_(2) hydrolysis as hydrogen generation.

关键词： MgH_(2) Hydrolysis reaction Cations anions Hydrogen generation

Effects of thiocyanate anions on switching and structure of poly(N-isopropylacrylamide) brushes

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Chinese Physics B 2019年第6期28卷 262-269页

作者： Xin-Jun Zhao Zhi-Fu Gao Xinjiang Laboratory of Phase Transitions and Microstructures of Condensed Matter Physics Yili Normal UniversityYining 835000China Laboratory of Micro-Nano Electro Biosensors and Bionic Devices Yili Normal UniversityYining 835000China Xinjiang Astronomical Observatory Chinese Academy of Sciences150Science 1-StreetUrumqi 830011China

In this work, we investigate the effects of thiocyanate anions on the switching and the structure of poly(Nisopropylacrylamide)(PNIPAM) brushes using a molecular theory. Our model takes into consideration the PNIPAM–anion bonds, the electrostatic effects and their explicit coupling to the PNIPAM conformations. It is found that at low thiocyanate anion concentration, as the anion concentration of thiocyanate increases, thiocyanate anions are more associated with PNIPAM chains through the PNIPAM–anion bonds, which contributes to stronger electrostatic repulsion and leads to an increase of lower critical solution temperature(LCST). By analyzing the average volume fractions of PNIPAM brushes,it is found that the PNIPAM brush presents a plateau structure. Our results show that the thiocyanate anions promote phase segregation due to the PNIPAM–anion bonds and the electrostatic effect. According to our model, the reduction of LCST can be explained as follows: at high thiocyanate anion concentration, with the increase of thiocyanate concentration, more ion bindings occurring between thiocyanate anions and PNIPAM chains will result in the increase of the hydrophobicity of PNIPAM chains;when the increase of electrostatic repulsion is insufficient to overcome the hydrophobic interaction of PNIPAM chains, it will lead to the reduction of brush height and LCST at high thiocyanate anion concentration. Our theoretical results are consistent with the experimental observations, and provide a fundamental understanding of the effects of thiocyanate on the LCST of PNIPAM brushes.

关键词： molecular theory PNIPAM brushes effect of thiocyanate anions

An experimental study of electroreduction of CO2 to HCOOH on SnO2/C in presence of alkali metal cations(Li^+,Na^+,K^+,Rb^+and Cs^+)and anions(HCO3^-,Cl^-,Br^-and I^-)

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Chinese Journal of Chemical Engineering 2020年第10期28卷 2549-2554页

作者： Qi Zhang Xiaolin Shao Jin Yi Yuyu Liu Jiujun Zhang Institute for Sustainable Energy College of SciencesShanghai UniversityShanghai 200444China

It is well-known that the electrolytes can influence the electrochemical reduction of carbon dioxide(ERCO2)in aqueous *** this work,we explore the effects of alkali metal cations and anions(Li^+,Na^+,K^+,Rb^+,Cs^+,HCO3^-,Cl^-,Br^-,I^-)on the current density and product selectivity for the ERCO2 into formic acid(HCOOH)on the SnO2/carbon paper(Sn O2/C)*** of the ERCO2 experiments show that for the cations,the promotion effects on current density and faradaic efficiencies(FEs)are in the order of Li^+b Na^+b K^+b Cs^+b Rb^+.For the anions,the current density values are in the order of Na HCO3 b NaClb Na Br b Na I and KHCO3 b KCl≈KI b KBr,respectively,and that on the FEs for the formation of the HCOOH(FEHCOOH)is HCO3-b Cl-b Br-b I-.Based on this result,the effects of alkali metal cations and anions on ERCO2 are discussed.

关键词： Carbon dioxide Electroreduction SnO2 electrode Effects anions Cations

Hydroxyl radical production by abiotic oxidation of pyrite under estuarine conditions:The effects of aging,seawater anions and illumination

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Journal of Environmental Sciences 2024年第1期135卷 715-727页

作者： Ruixue Liu Yinshun Dai Yucheng Feng Shiwen Sun Xiaodong Zhang Chunjiang An Shan Zhao Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and EngineeringShandong UniversityQingdao 266237China Department of Building Civil and Environmental EngineeringConcordia UniversityMontrealQC H3G 1M8Canada

Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions is still poorly *** batch experiments were performed to investigate the effects of estuarine conditions including aging(in air,in water),seawater anions(Cl^(-),Br^(-)and HCO_(3)^(-))and light on the HO^(·)production by pyrite *** one-electron transfer dominated the process from O_(2) to HO^(·)induced by oxidation of *** Fe(oxyhydr)oxide coatings on the surface of pyrite aged in air and water consumed hydrogen peroxide while mediating the electron transfer,and the combined effect of the two resulted in a suppression of HO^(·)production in the early stage of aging and a promotion of HO^(·)production in the later stage of *** of the surface oxide layers by aggressive anions was the main reason for the inhibition of HO^(·)production by Cl^(-)and Br^(-),and the generation of Cl^(·)and Br^(·)may also play a role in the scavenging of HO^(·).HCO_(3)^(-)increased the average rate of HO^(·)production through surface-CO_(2) complexes formed by adsorption on the surface of *** significant enhancement of HO^(·)production under light was attributed to the formation of photoelectrons induced by photochemical reactions on pyrite and its surface oxide *** findings provide new insights into the environmental chemical behavior of pyrite in the estuary and enrich the understanding of natural remediation of estuarine environments.

关键词： Hydroxyl radical Pyrite oxidation Aging anions Irradiation

Effect of amendments on the leaching behavior of alkaline anions and metal ions in bauxite residue

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Journal of Environmental Sciences 2019年第11期31卷 74-81页

作者： Tao Tian Jinaju Zhou Feng Zhu Yuzhen Ye Ying Guo William Hartley Shengguo Xue School of Metallurgy and Environment Central South University Changsha 410083 China Crop and Environment Sciences Department Harper Adams University Newport Shropshire TF10 8NB UK

A column leaching experiment was used to investigate the efficacy of amendments on their ability to remove alkaline anions and metal ions from bauxite residue *** included,simulated acid rain (AR),phosphogypsum + vermicompost (PVC),phosphogypsum + vermicompost + simulated acid rain (PVA),and biosolids + microorganisms (BSM) together with controls (CK).Results indicated that amendment could effectively reduce the leachate pH and EC values,neutralize OH-,CO32-,HCO3-,and water soluble alkali,and suppress arsenic (As) *** analysis revealed significant linear correlations with pH and concentrations of OH-,CO32-,HCO3-,water-soluble alkali,and metal *** treatment showed optimum results with neutralizing anions (OH-,CO32-,and HCO3-),water soluble alkali,and removal of metal ions (Al,As,B,Mo,V,and Na),which was attributed to neutralization from the generation of small molecular organic acids and organic matter during microbial *** treatment reduced alkaline anions and metal ions based on neutralization reactions in bauxite residue leachate,which reduced the potential pollution effects from leachates on the soil surrounding bauxite residue disposal areas.

关键词： Bauxite residue leachate Amendments Alkaline anions Metal ions

Observation of Electronic Shells and Characteristic Products from Mass Abundance Spectra of Al Cluster and Al-C Cluster anions

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Chinese Physics Letters 2000年第9期17卷 658-660页

作者： LIU Bing-chen ZHAI Hua-Jin ZHOU Ru-fang NI Guo-Quan XU Zhi-Zhan Laboratory for Quantum Optics Chinese Academy of SciencesShanghai 201800 Laboratory for High Intensity Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800

Using a laser vaporization/pulsed molecular beam cluster source,Al cluster anions and Al-C mixed cluster anions are produced and recorded by a time of flight mass *** abundance spectra of the Al cluster anions in the size range from Al_(2)^(-)to Al_(42)^(-)show that Al_(13)^(-),Al_(23)^(-),Al_(35)^(-),and slightly,Al_(37)^(-)are local maxima,as predicted by the electronic jellium *** clusters Aln C-and Aln C_(2)^(-)are also shown,among which the most abundant species are Al3 C2,Al6 C_(2)^(-),A_(l7)C^(-)and A_(l7)C_(2)^(-)in the small size *** formation mechanism of these products is discussed.

关键词： cluster slightly anions

Impact of anions on the heavy metals release from marine sediments

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Journal of Environmental Sciences 2006年第6期18卷 1216-1220页

作者： ZHONG Ai-ping GUO Shu-hai LI Feng-mei LI Gang JIANG Ke-xu Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China Graduate School of Chinese Academy of Sciences Beijing 100039 China Institute of Environmental Science Huludao 125000 China

Marine sediments from Lianshan Bay in Huludao, China, were studied in laboratory. A series of simulated experiments were carried out to investigate the influences of three kinds of anions CL^-, SO4^2- and HCO3^- on the release ofCd, Pb, Cu and Zn from the sediments. The results showed that the sequences about the impact of the three anions were Cl^-〉HCO3^-〉SO4^2＋. The release potential of heavy metals in the presence of each anions was in the following order： Cd≥Cu 〉Zn≈Pb. The correlations were positive between CI content and the quantity of Cd released from the marine sediment, whereas there was no significant relationship between CI content and amount of Cu and Zn released. For SO4^2- and HCO3^-, the release of the heavy metals from marine sediments was not obvious.

关键词： marine sediments anions heavy metals release

The role of hydrated anions in hydration lubrication

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Nano Research 2023年第1期16卷 1096-1100页

作者： Zibo Li Qian Liu Qiang Li Mingdong Dong Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education School of Chemistry and Chemical EngineeringShandong UniversityJinan 250100China Interdisciplinary Nanoscience Center(iNANO) Aarhus UniversityAarhus C DK-8000Denmark

Hydration lubrication has long been invoked to account for the ultralow sliding friction between charged surfaces in aqueous environments,but still not well understood at ***,we explored the lubrication effect of hydrated halogen anions on positively charged surface at the atomic scale by using three-dimensional atomic force microscopy and friction force *** resolved three-dimensional imaging revealed that the anion layer was topped by a few hydration *** mechanical properties of the hydration layers were found mainly dependent on the concentration of electrolyte solutions and independent of the species of hydrated ***-scale friction experiments showed that the hydration friction coefficient and friction dissipation at low concentrations were orders of magnitude lower than that at high concentrations and in pure *** can be achieved in low concentration electrolyte *** results indicated that the changes of electrolyte solution concentrations led to different adsorption state of anions on the positively charged surface which gave rise to the difference of the friction *** findings in this study reveal the role of hydrated anions in hydration lubrication and provide deep insights into the origins of hydration lubrication.

关键词： hydration lubrication hydration structures anions friction three-dimensional atomic force microscopy(3D-AFM)