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Progress of gaseous arsenic removal from flue gas by adsorption:Experimental and theoretical calculations

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Journal of Environmental Sciences 2024年第2期136卷 470-485页

作者： Xuelei Yan Qingzhu Li xiaowei Huang Bensheng Li Shengtu Li Qingwei Wang School of Metallurgy and Environment Central South UniversityChangsha 410083China National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution Central South UniversityChangsha 410083China National Engineering Research Center for Rare Earth Materials General Research Institute for Non-Ferrous MetalsBeijing 100088China

Because of its high mobility and difficult capture,gaseous arsenic pollution control has become the focus of arsenic pollution control.It mainly exists in the form of highly toxic As_(2)O_(3)in the flue gas.Therefore,removing gaseous As_(2)O_(3)from flue gas is of great practical significance for arsenic pollution control.Stabilizing gaseous As_(2)O_(3)on the surface of adsorbents by physical or chemical adsorption is an effective way to reduce the content of arsenic in the flue gas and alleviate arsenic pollution.Over the past few decades,various adsorbents have been developed to capture gaseous As_(2)O_(3)in the flue gas,and their adsorption mechanisms have been studied in detail.Thus,it is necessary to review the strategies of arsenic removal from flue gas by adsorption,which can inspire further research.Based on summarizing the morphological distribution of gaseous As_(2)O_(3)in the flue gas,this review further summarizes the removal of gaseous As_(2)O_(3)by several adsorbents and the effect of temperature and the main components of the flue gas on arsenic adsorption.In addition,the mechanism of arsenic removal based on adsorption in the flue gas is discussed in depth through theoretical calculations,which is the particular focus of this review.Finally,prospects based on the present research state of arsenic removal by adsorption are proposed to provide ideas for developing effective and stable adsorbents for arsenic removal from flue gas.

关键词： Gaseous arsenic Flue gas Adsorption Theoretical calculation Mechanism

Behavior of phase transformation of Baotou mixed rare earth concentrate during oxidation roasting

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Journal of Rare Earths 2022年第6期40卷 981-987,I0005页

作者： Deliang Meng Meng Wang Zongyu Feng Chao Xia Yanyan Zhao xiaowei Huang School of Metallurgy Northeastern UniversityShenyang 110819China National Engineering Research Center for Rare Earth Materials GRINM Group Co.Ltd.Beijing 100088China General Research Institute for Nonferrous Metals Beijing 100088China GRIREM Advanced Materials Co. Ltd.Beijing 100088China

Based on the new process named "Combination Method" for metallurgy and separation of Baotou mixed rare earth concentrate(BMREC),the aim of this paper is to clearly elucidate the phase change behavior of BMREC without additives during oxidative roasting at 450-800℃.The results indicate that the bastnaesite in BMREC is decomposed at 450-550℃,the weight loss is about 10.3 wt%,and the activation energy(E) is 144 kJ/mol.The bastnaesite in BMREC is decomposed into rare earth fluoride,rare earth oxides(La_(2)O_(3),Ce_(7)O_(12),Pr_(6)O_(11) and Nd_(2)O_(3)),and CO_(2),particularly,with the increase of roasting temperature,bastnaesite in BMREC is more completely decomposed into LaF_(3),which causes a decrease in leaching rate of La during the HCI leaching process.Additionally,the maximum cerium oxidation efficiency reaches about 60 wt% when the roasting temperature is equal to or above 500℃,and the oxidation reaction rate of cerium increases with the increasing roasting temperature.

关键词： Phase change Combination method Oxidation roasting Cerium oxidation efficiency Rare earths

Tailoring thermal stability of ceria-zirconia mixed oxide by doping of rare earth elements:From theory to experiment

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Journal of Rare Earths 2022年第8期40卷 1272-1280页

作者： Zheng Zhao xiaowei Huang Yongqi Zhang Juanyu Yang Meisheng Cui Yongke Hou Zongyu Feng National Engineering Research Center for Rare Earth Materials GRINM Group Corporation LimitedBeijing 100088China Griem Hi-tech Co. Ltd.Langfang 065000China Rare Earth Functional Materials(Xiong’an)Innovation Center Co. Ltd.Baoding 071700China

Ceria-zirconia mixed oxides(CZMO)are widely used in many important catalysis fields.However,pure CZMO is known to have poor thermal stability.In this paper,a strategy was proposed to design Ce_(0.475)Zr_(0.475)M_(0.05)O_(2)(M=La,Y,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Er,Lu,and,Yb)oxide surface with high thermal stability by using first-principles molecular dynamics(FPMD)simulation and experiment method.Through the structure stability analysis at different temperatures,the surface energyγas a function of R_(ion)/D_(ave)is identified as a quantitative structure descriptor for analyzing the doping effect of rare earth(RE)elements on the thermal stability of Ce_(0.475)Zr_(0.475)M_(0.05)O_(2).By doping the suitable RE,γcan be adjusted to the optimal range to enhance the thermal stability of Ce_(0.475)Zr_(0.475)M_(0.05)O_(2).With this strategy,it can be predicted that the sequence of thermal stability improvement is Y>La>Gd>Nd>Pr>Pm>Sm>Eu>Tb>Er>Yb>Lu,which was further verified by our experiment results.After thermal treatment at 1100℃for 10 h,the specific surface area(SSA)of aged Y-CZ and La-CZ samples can reach 21.34 and 19.51 m~2/g,which is 63.02%and 49.04%higher than the CZMO sample without doping because the surface doping of Y and La is in favor of inhibiting the surface atoms thermal displacement.In a word,the strategy proposed in this work can be expected to provide a viable way for designing the highly efficient CZMO materials in extensive applications and promoting the usages of the high-abundance rare-earth elements Y and La.

关键词： Cerium zirconium oxides surface Thermal stability Doping Structure descriptor Rare earth metals Theory and experiment

Extraction mechanism and separation behaviors of low-concentration Nd^(3+) and Al^(3+) in P507-H_(2)SO_(4) system

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Journal of Rare Earths 2022年第6期40卷 952-957,I0004页

作者： Hongyuan Zhang Longsheng Zhao Xudong Zheng Depeng Liu Zongyu Feng Yongqi Zhang xiaowei Huang National Engineering Research Center for Rare Earth Materials GRINM Group Co.Ltd.Beijing 100088China General Research Institute for Nonferrous Metals Beijing 100088China Grirem Advanced Materials Co. Ltd.Beijing 100088China Rare Earth Functional Materials(Xiong’an)Innovation Center Co. Ltd.Baoding 071700China

In order to clarify the solvent extraction and separation behaviors of rare earths and impurity of Al during the extraction and enrichment of low-concentration leach solution of ion-adsorption rare earth ore,the extraction mechanism and separation behaviors of Nd^(3+)and Al^(3+)in the Nd_(2)(SO_(4))_(3)-AI_(2)(SO_(4))_(3) mixed solution using P507 were studied in this work.The extraction of Nd^(3+)and Al^(3+)follows the cation exchange mechanism.With the increase of the equilibrium pH,β_(Nd/Al) in the extraction of the Nd_(2)(SO_(4))_(3)-Al_(2)(SO_(4))_(3) mixed solution using P507 is always higher than that in the extraction of single Nd_(2)(SO_(4))_(3) and Al_(2)(SO_(4))_(3) solutions.It can be attributed to the fact that the extraction of Nd^(3+)using P507 is much faster than that of Al^(3+),and Al^(3+)is more prone to be hydrolyzed at lower pH.β_(Nd/Al) in the extraction of the Nd_(2)(SO_(4))_(3)-Al_(2)(SO_(4))_(3) mixed solution decreases gradually with the increase of mixing time within the equilibrium pH range of 1.5-1.9.The extraction of Nd^(3+)using P507 is much faster than that of Al^(3+),but the stability of Al^(3+)-Ioaded organic phase is better than that of Nd^(3+)-loaded organic phase,thus Nd^(3+)in the Nd^(3+)-loaded organic phase is gradually replaced by Al^(3+)in the aqueous phase with the increase of mixing time.

关键词： Ion-adsorption rare earth ore Low-concentration rare earth Aluminum Extraction mechanism Separation factor

Multiple olfactory pathways contribute to the lure process of Caenorhabditis elegans by pathogenic bacteria

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Science China(Life Sciences) 2021年第8期64卷 1346-1354页

作者： Man Zhu Yao Chen Ninghui Zhao Hua Bai Keqin Zhang xiaowei Huang State Key Lab for Conservation and Utilization of Bio-Resources and College of Life ScienceYunnan UniversityKunming 650091China Neurosurgery of the Second Hospital Affiliated with Kunming Medical University Kunming 650101China College of Public Health Kunming Medical UniversityKunming 650500China

Chemosensation is indispensable for the survival of Caenorhabditis elegans to discriminate food and pathogenic bacteria in their living environment. Food-like odors emitted by the pathogen Bacillus nematocida B16 for trapping its hosts and an olfactory signaling pathway responsible to sense the attractant 2-heptanone were identified in our previous study. Here, we further explore how the worms recognize the attractive molecules indole and 2-ethyl hexanol, which have different chemical properties and modest nematode-luring ability. We show that the chemotaxis toward indole and 2-ethyl hexanol requires the G protein-coupled receptors encoded by str-193 on AWC and str-7 on AWA. In a further genetic screen for downstream effectors in olfactory signaling cascades, the Gα subunit GSA-1, guanylyl cyclase ODR-1 and DAF-11 and the c GMP-gated channel TAX-2/TAX-4 were found to be necessary for indole sensation, whereas the TRPV channels OSM-9/OCR-2 and the PLC pathway activated by GPA-6 are responsible for the detection of 2-ethyl hexanol. Altogether, our current work further clarifies the distinct olfactory signaling pathways through which C. elegans senses different chemicals and is lured by B. nematocida B16, improving our comprehensive understanding of the mechanisms by which bacterial pathogens effectively infect their hosts.

关键词： attractive trapping process

Dense Mapping From an Accurate Tracking SLAM

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IEEE/CAA Journal of Automatica Sinica 2020年第6期7卷 1565-1574页

作者： Weijie huang Guoshan Zhang xiaowei Han School of Electrical and Information Engineering Tianjin UniversityTianjin 300072China Institute of Information Engineering Shenyang UniversityShenyang 110044China

In recent years, reconstructing a sparse map from a simultaneous localization and mapping(SLAM) system on a conventional CPU has undergone remarkable progress. However,obtaining a dense map from the system often requires a highperformance GPU to accelerate computation. This paper proposes a dense mapping approach which can remove outliers and obtain a clean 3D model using a CPU in real-time. The dense mapping approach processes keyframes and establishes data association by using multi-threading technology. The outliers are removed by changing detections of associated vertices between keyframes. The implicit surface data of inliers is represented by a truncated signed distance function and fused with an adaptive weight. A global hash table and a local hash table are used to store and retrieve surface data for data-reuse. Experiment results show that the proposed approach can precisely remove the outliers in scene and obtain a dense 3D map with a better visual effect in real-time.

关键词： Adaptive weights data association dense mapping hash table simultaneous localization and mapping(SLAM)

Grain boundary segregation and its influences on ionic conduction properties of scandia doped zirconia electrolytes

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Journal of Rare Earths 2019年第6期37卷 645-651页

作者： Qiannan Xue xiaowei Huang Jianxing Zhang He Zhang Zongyu Feng National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals Grirem Advanced Materials Co. Ltd.

Solid oxide fuel cell is a promising energy conversion system which converts chemical energy into electrical energy directly. Electrolyte is the key component and determines the working temperature. In this paper,ceria and scandia co-doped zirconia electrolytes sintered from 1300 to 1550 ℃ were chosen as research objects. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy were performed to characterize the ceramic samples. The effects of grain size and grain boundary element segregation on the electrical conductivity were focused. Electrochemical impedance spectroscopy was used to calculate the bulk, grain boundary and specific grain boundary conductivity. Results show that the bulk and grain boundary ionic conductivity increases with the increasing grain size.However, the specific grain boundary conductivity decreases with the increasing grain size. This is explained by the fact that Sc^(3+) is segregated at the grain boundary, which leads to higher oxygen vacancy concentration when sintered at lower temperature.

关键词： Electrolytes Co-doped zirconia Grain size Dopant segregation Ionic conductivity Rare earths

Behavior of sulfate in preparation of single light rare earth carbonate by Mg(HCO_(3))_(2) precipitation method

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Journal of Rare Earths 2021年第7期39卷 850-857,I0004页

作者： Meng Wang xiaowei Huang Zongyu Feng Chao Xia Deliang Meng Zonghe Yu National Engineering Research Center for Rare Earth Materials GRINM Group Co.Ltd.Beijing 100088China GRIREM Advanced Materials Co. Ltd.Beijing 100088China General Research Institute for Nonferrous Metals Beijing 100088China Rare Earth Functional Materials(Xiong'an)Innovation Center Co. Ltd.Baoding 071700China

The precipitation of the water-leaching solution of Baotou mixed rare earth(RE) concentrate roasted with sulfuric acid using ammonium bicarbonate for producing RE carbonate produces a mass of ammonia-nitrogen wastewater because of the relatively low solubility of rare earth sulfate.To solve the serious problem of ammonia-nitrogen pollution,new precipitators need to be developed urgently so as to meet the requirements of environmental protection and impurities content of the product(SO_(4)^(2-)<1.8 wt% in RE carbonates products).In this paper,we studied the effects of feeding modes on the behavior of SO_(4)^(2-) during the preparation of light RE carbonate(RE=La,Ce,Pr,Nd) from their sulfate solutions using Mg(HCO_(3))_(2) as a precipitant.The results indicate that the contents of SO_(4)^(2-) in the La and Ce precipitates using positive feeding mode exceed 16 wt% because of the formation of La_(2)(CO_(3))2.15(-SO_(4))0.85·4 H_(2)O and Ce_(2)(CO_(3))_(2).15(SO_(4))0.85·3H_(2)O,while those of the Pr and Nd precipitates are 4 wt%-5 wt% since they exist in the form of n-carbonate.The precipitates prepared using synchronous feeding mode are all RE carbonate with only 4 wt%-5 wt% of SO_(4)^(2-) enclosed in the precipitation.The content of SO_(4)^(2-) in the RE carbonate obtained using reverse feeding mode is the lowest.Among them,the content of SO_(4)^(2-) in La precipitate is only 1.40 wt%.Both synchronous and reverse feeding modes can effectively reduce the content of SO_(4)^(2-)in RE carbonate,which provides theoretical guidance for the preparation of qualified light RE carbonate products by Mg(HCO3)2 precipitation method.

关键词： Rare earth sulfate Magnesium bicarbonate Rare earth carbonate Sulfate ion Complex salt

SO_(4)^(2-)-modified La,Y-doped ceria-zirconia with high oxygen storage capacity and its application in Pd-only three-way catalysts

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Journal of Rare Earths 2022年第5期40卷 737-744,I0003页

作者： Hao Wang Yongke Hou Yongqi Zhang Meisheng Cui Fang Chen xiaowei Huang Juanyu Yang Zongyu Feng National Engineering Research Center for Rare Earth Materials GRINM Group Corporation LimitedBeijing 100088China Grirem Hi-tech Co. Ltd.Langfang 065000China Grirem Advanced Materials Co. Ltd.Beijing 100088China Rare Earth Functional Materials(Xiong’an)Innovation Center Co. Ltd.Baoding 071700China

As the oxygen redox ability shows great effects on the catalytic performances of ceria-zirconia based materials,many strategies have been utilized to improve the oxygen storage capacity.Here in this study,we report a simple and facile approach to prepare a SO_(4)^(2-)-modified La,Y-doped ceria-zirconia material(SO/CZLY-f)with high oxygen storage capacity.Due to the additional redox process between SO_(4)^(2-)and S^(2-),oxygen storage capacity of SO/CZLY-f(745.3μmol O_(2)/g)is about 1.6 times higher than that of La,Ydoped ceria-zirconia material without SO_(4)^(2-)modification.Moreover,the catalytic activities and stability of the corresponding Pd-only three-way catalyst were measured.Compared to that of Pd@CZLY-f,the operation window of CO,full conversion temperature of HC and NO over Pd@SO/CZLY-f are obviously widened and lowered,respectively.After aging treatment at 1100℃for 4 h,the superiority of aged Pdloading composite is still maintained.

关键词： SO_(4)^(2-)-modified La Y-doped ceria-zirconia Oxygen storage materials Three-way catalytic performances Rare earths