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Photocatalytic Reduction of Cr^Ⅵ by Natural Sphalerite Suspensions under Visible Light Irradiation

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Acta Geologica Sinica(English Edition) 2006年第2期80卷 267-272页

作者： LI Yan LU Anhuai wang changqiu School of Earth and Space Sciences Peking University Beijing 100871

The photocatalytic reductive capability of a natural semiconducting mineral, sphalerite has been studied for the first time. The sphalerite from the Huangshaping deposit of Hunan Province performed great photoreductive capability that 91.95% of the Cr^6＋ was reduced under 9 h visible light irradiation, higher than the 70.58% under 9.5 h UV light irradiation. The highly reductive ability results from its super negative potential of electrons in the conduction band. Furthermore, Fe substitution for Zn introduces donor states, and the oxidation process of Fe^2＋ to Fe^3＋ makes it an effective hole-scavenger. Cd and Cu substitute for Zn also reduce the bandgap and help broaden the absorbing edge towards the visible light. These substituting metal ions in natural sphalerite make it a hyper-active photocatalyst and very attractive for solar energy utilization.

关键词： natural sphalerite photoreduction Cr^6+ visible light substituting ions bandgap

Semiconducting Mineral Photocatalytic Regeneration of Fe^(2+) Promotes Carbon Dioxide Acquisition by Acidithiobacillus ferrooxidans

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Acta Geologica Sinica(English Edition) 2013年第3期87卷 761-766页

作者： LI Yan LU Anhuai wang Xin DING Hongrui wang changqiu The Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University

Chemoautotrophic organisms have once been excluded from the development of universally applicable CO2 fixation technology due to its low production yields of biomass. In this study, we used Acidithiobacillusferrooxidans （A.f.） as a model chemoautotrophic microorganism to test the hypothesis that exogenetic photoelectrons from semiconducting mineral photocatalysis can enable the regeneration of Fe^2＋ that could be then used by A.f. and support its growth. In a simulated electrochemical system, where exogenetic electrons were provided by an electrochemical approach, an accelerated growth rate of A.f. was observed as compared with that in traditional batch cultivation. In a coupled system, where light-irradiated natural rutile provided the primary electron source to feed A.f., the bacterial growth rate as well as the subsequent CO2 fixation rate was demonstrated to be in a light-dependent manner. The sustaining flow of photogenerated electrons from semiconducting mineral to bacteria provided an inexhaustible electron source for chemoautotrophic bacteria growth and CO2 fixation. This finding might contribute to the development of novel effective CO2 fixation technology.

关键词： CO2 fixation photocatalysis chemoautotrophic organisms semiconducting mineral

Mimicking natural paragenetic semiconducting minerals MoS2/sphalerite：A simple method to fabricate visible-light photocatalyst

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Science China(Technological Sciences) 2017年第12期60卷 1870-1877页

作者： LIU Yi LI Yan LU AnHuai wang changqiu DING HongRui The Key Laboratory of Orogenic Belts and Crustal Evolution Beijing Key Laboratory of Mineral Environmental Function School of Earth and Space Sciences Peking University Beijing 100871 China

Natural paragenetic semiconducting minerals give important hints for fabricating stable and effective photocatalysts, which can be widely used in solar energy harvest and pollution control. To enhance the photoactivity of natural sphalerite(ZnS), needle-like nanocrystal MoS_2 was loaded on sphalerite surface through a hydrothermal method, mimicking the intergrowth of molybdenite(MoS_2) and sphalerite in nature. The resultant coupled MoS_2/sphalerite exhibited a hydrogen evolution reaction(HER) potential at-0.35 V(vs. NHE), and showed obvious photoresponse under visible-light. The photodegradation rate of methyl orange(MO) over MoS_2/sphalerite could reach 75% within 180 min. Compared to sphalerite, coupled MoS_2/sphalerite had a higher photocurrent,more positive HER potential and 66% higher photodegradation rate. The enhanced photoactivity was attributed to the charge transfer from sphalerite to MoS_2 and high electrons' mobility on MoS_2 layer.

关键词： sphalerite MoS2 coupled semiconductor visible-light photocatalysis

Photoelectrochemical performance of birnessite films and photoelectrocatalytic activity toward oxidation of phenol

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Journal of Environmental Sciences 2017年第2期29卷 259-267页

作者： Huiqin Zhang Hongrui Ding Xin wang Cuiping Zeng Anhuai Lu Yan Li changqiu wang The Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University Institutes of Science and Development Chinese Academy of Sciences

Birnessite films on fluorine-doped tin oxide（FTO） coated glass were prepared by cathodic reduction of aqueous KMnO4. The deposited birnessite films were characterized with X-ray diffraction, Raman spectroscopy, scanning electron microscopy and atomic force *** photoelectrochemical activity of birnessite films was investigated and a remarkable photocurrent in response to visible light was observed in the presence of phenol, resulting from localized manganese d–d transitions. Based on this result, the photoelectrocatalytic oxidation of phenol was investigated. Compared with phenol degradation by the electrochemical oxidation process or photocatalysis separately, a synergetic photoelectrocatalytic degradation effect was observed in the presence of the birnessite film coated FTO *** degradation ratios were influenced by film thickness and initial phenol concentrations. Phenol degradation with the thinnest birnessite film and initial phenol concentration of 10 mg/L showed the highest efficiency of 91.4% after 8 hr. Meanwhile, the kinetics of phenol removal was fit well by the pseudofirst-order kinetic model.

关键词： Birnessite Photoelectrochemical activity Photocurrent Photoelectrocatalytic oxidation Phenol

Geometry,kinematics and evolution of the Tongbai orogenic belt

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Science China Earth Sciences 2006年第8期49卷 828-838页

作者： HUANG Shaoying XU Bei wang changqiu ZHAN Sheng DENG Rongjing The Key Laboratory of Orogenic Belts and Crustal Evolution Peking University Ministry of EducationBeijing 100871China

The Tongbai orogenic belt(TOB)is composed of six tectonic *** south to north these units are:Tongbai gneiss rise(TGR);Hongyihe-Luozhuang eclogite belt(HLE);Ma-opo-Hujiazhai igneous rock belt(MHI);Zhoujiawan flysch belt(ZFB);Yangzhuang greenschist belt(YGB);and Dongjiazhuang marble belt(DMB).The geometry and kinematic images of the TOB in-clude:the antiformal structures caused by a later uplift process,the top-to-north ductile shear struc-ture that related to a process that the ultrahigh pressure rocks are brought to surface,the top-to-south ductile shear thrust and the sinistrial shear structures related to a south-north direction compression,and the east-west direction fold structures in the upper *** the view of the multistage subduc-tion-collision orogenic belt,according to the characters of petrology and its distribution,geometry,kinematics and structural chronology in these tectonic units,tectonic evolution of the TOB can be divided into four stages:oceanic crust subduction during 400―300 Ma,continental collision during 270―250 Ma,continental deep subduction and uplift during 250―205 Ma and doming deformation during 200―185 Ma.

关键词： Tongbai geometry kinematics tectonic unit orogenic belt evolution

The fluid inclusions in jadeitite from Pharkant area, Myanmar

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Chinese Science Bulletin 2000年第20期45卷 1896-1901,1923页

作者： SHI Guanghai CUI Wenyuan wang changqiu ZHANG Wenhuai Department of Geology Peking UniversityBeijing 100871China Institute of Resource China University of GeosciencesWuhan 430074China

A lot of liquid-gas and liquid-gas-solid inclusions were found in Pharkant jadeitites, northwestern Myanmar and their characteristics, geological setting and porphyroclastic jadeites with inclusions in them were described in detail. The results analyzed by Raman spectrometer showed that the component of liquid-gas phase and solid phase (daughter minerals) in fluid inclusions is H2O + CH4 and jadeite separately. The results indicated that Pharkant jadeitites were crystallized from H2O + CH4 bearing jadeitic melt which may originate from mantle. The P-T conditions in which the jadeitites were crystallized were speculated to be T>650℃, P>1.5 GPa.

关键词： Pharkant Myanmar jadeitite jadeite fluid inclusion H2O + CH4 jadeitic melt mantle.

Experimental Study on Formation Conditions of Ammoniojarosite and Its Environmental Significance

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Acta Geologica Sinica(English Edition) 2006年第2期80卷 296-301页

作者： wang changqiu MA Shengfeng LU Anhuai ZHOU Jiangong School of Earth and Space Sciences Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education Peking University Beijing 100871 National Research Center of Geoanalysis Beijing 100037

Formation conditions of ammoniojarosite in system Fe2（SO4）3-（NH4）2SO4-H2O are investigated in this paper. The results show that ammoniojarosite can be formed rapidly under normal temperature and pressure by controlling suitable pH value and Fe2（SO4）3 and （NH4）2SO4 concentrations. The pH value, temperature and concentration of Fe2（SO4）3 medium are key factors influencing the formation of ammoniojarosite. Under normal temperature, precipitation of ammoniojarosite can be seen within 24 hours at pH values between 2.6-3.1, and a great quantity of ammoniojarosite is formed within 48 hours. At about 90℃, the pH value range forming ammoniojarosite extends to 1.2-3.1, and within this range the rise of pH value is advantageous to the formation of ammoniojarosite and high Fe2（SO4）3 concentration is also advantageous. Relative pure ammoniojarosite is synthesized under high Fe2（SO4）3 concentration （≥0.05 M） and ammoniojarosite containing melanterite and colloid amorphous hydroxide vitriol iron is formed at low Fe2（SO4）3 concentration. The deposition process of ammoniojarosite can be used to harness wastewater from mines and other industries and remove S, Fe and other toxic and harmful elements, such as As, Cr, Hg, Pb in water. Rapid formation of ammoniojarosite and other jarosite analogs under normal temperature and pressure has a good potential prospect for harnessing acid wastewater by means of precipitation of jarosite and its analogs.

关键词： ammoniojarosite formation conditions harness of acid wastewater environmental significance

Experimental Study on Treatment of High-concentrated Sulfur Wastewater by Process of Depositing Natrojarosite and Its Environmental Significance

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Acta Geologica Sinica(English Edition) 2007年第2期81卷 330-334页

作者： MA Shengfeng wang changqiu LU Anhuai GUO Yanjun HE Hongliao School of Earth and Space Sciences Peking University Beijing 100871 The Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education National Research Center of Geoanalysis Beijing 100037

High-concentrated sulfur wastewater with sodium and COD （chemical oxygen demand） up to 26000 mg/L from a chemical plant, Jiangsu Province of China has been treated by deposition of natrojarosite in lab. The results indicated that the COD of the wastewater was decreased sharply from 26000 mg/L to 1001 mg/L, with removal rate of COD up to 96% by twice precipitations of natrojarosite and twice oxidation of H202. The treated sulfur wastewater reached the requirement of subsequent biochemical treatment to water quality. The optimal operational parameters should be controlled on pH value between 2.50 and 3.20 and 50 g FeCly6H2O solid added in per liter wastewater. The study provided an experimental basis for pretreatment of high-concentrated sulfur wastewater and proposed a new mineralogical method on treatment of other wastewaters. Depositing process of jarosite and its analogs should be able to be used to treat wastewater from mine and other industries to remove S, Fe and other toxic and harmful elements, such as As, Cr, Hg, Pb, etc. in the water.

关键词： natrojarosite high-concentrated sulfur wastewater COD environmental significance

Porous Properties of Nano-fibriform Silica from Natural Chrysotile

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Acta Geologica Sinica(English Edition) 2006年第2期80卷 180-184页

作者： wang Lijuan LU Anhuai wang changqiu LI Xuejun ZHENG Xishen ZHAO Dongjun LIU Rui State Key laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 School of Earth and Space Science Peking University Beijing 100871 Key Laboratory of Lithosphere Tectonics and Lithoprobing Techology of Ministry of Education China University of Geosciences Beijing 100083 College of Tourism and Geography Jilin Normal University Siping Jilin 136000 Land and Resources Department Changchun Institute of Technology Changchun Jilin 130021

With the TEM and physical gas adsorption techniques, porous properties of nano-ribriform silica （MLD： 92.73%） from natural chrysotile are studied in this paper. The results indicate that porous nano-fibriform silica results from brucite octahedral sheets of nature chrysotile dissolved completely and Si-O tetrahedral sheets collapsed by acid leaching. Its length is at a micron or nanometer scale. There are two types of pores： pores among neighboring fibers and pores in nanoriber. These pores （less than 6.5 nm in diameter, mostly 2.1 nm and 3.8 nm） all belong to mesopores. The pores in fibers consist of those among SiO2 particles, those among aggregates, remnant nanotubes and capillary tubes. Nanoribriform silica proves better than the traditional silica as a carrier of catalyzer and a filler for reinforce rubber and plastics.

关键词： silica nano-ribriform porous properties chrysotile pore