• Volume 80,Issue 2,2006 Table of Contents
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    • Structural Evolvement of Heating Treatment of Mg/Al-LDH and Preparation of Mineral Mesoporous Materials

      2006, 80(2).

      Abstract (1453) HTML (0) PDF 0.00 Byte (102) Comment (0) Favorites

      Abstract:Although hydrotalcite, or layered double hydroxides (LDHs), is not a common mineral, it is an important material that can be easily synthesized in laboratory. In this study, structural evolvement and BET surface area changes of heat treated Mg/Al-LDH is evaluated by XRD, TEM and N2-BET analyses. The results indicate that the magnesium-aluminum LDH with carbonate as interlayer anion, periclase-like oxides was formed at temperatures of 400-800℃. Meanwhile, 2-3 nanometer mesoporous were formed during decomposition of LDH. However, the heat treated samples still preserve the morphology of the original LDH plates. Periclase-like formed from LDH heat treatment may re-hydrolyze and recover the structure of LDH. However, crystallinity of the recovered LDH is lower than that of the original LDH. This heat treatment will result in formation of (Mg, Al)-oxide nano-crystals and nanopores among the nano-crystals. When heating temperature exceeds 1000, the periclase-like (Mg, Al)-oxide is transformed into a composite with periclase (MgO) and spinel phases. The periclase can be re-hydrolyzed and dissolved in HCl solution. After acid treatment, the sample with a high surface area is composed of spinel nano-crystals and nanopores among them. Our results will provide a new and economic way to synthesize mesoporous materials through pathways of phase transformation of precursor materials with different composition.

    • Photocatalytic Reduction of Cr~Ⅳ by Natural Sphalerite Suspensions under Visible Light Irradiation

      2006, 80(2).

      Abstract (1239) HTML (0) PDF 0.00 Byte (108) Comment (0) Favorites

      Abstract: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 Cr6+ 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 Fe2+ to Fe3+ 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.

    • GUIDANCE FOR CONTRIBUTORS

      2006, 80(2).

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      Abstract:1. Papers should be devoted mainly to various aspects of research concerning geosciences and related disciplines in China, such as stratigraphy, paleontology, origin and history of the Earth, structural geology, tectonics, mineralogy, petrology, geochemistry, geophysics, geology of mineral deposits, hydrogeology, engineering geology, environmental geology, regional geology and new theories and technologies of geological exploration. Those of scientific interest to the geological community in China or of international interest are also welcome. 2. Only unpublished original papers, not simultaneously submitted or published elsewhere, will be accepted, and copyright in published papers will be vested in the publisher. 3. Papers, including text, text figures, tables, references and plates, are normally 5000 to 10,000 words long, but shorter papers are

    • Environmental Effects of Micro- and Ultra-microchannel Structures of Natural Minerals

      2006, 80(2):161-169.

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      Abstract:The micro-channels usually refers to structural channels of minerals with aperture in the range of 0.3 nm to 2.0 run. Such microchannels include, Mn-O octahedron channel filled by K in cryptomelane, and channel constructed by Si-O and AI-O tetragonal molecular sieve filled by Na and Ca in zeolite, and effectively have the function of molecular sieve. Here we point out that ultra-microchannels of natural minerals have apertures below 0.3 nm with the features of ionic sieves. The ultra-microchannels of mineral feldspar, accounting for half mass of the Earth's crust, have been largely ignored because the aperture is too small. In this work, we present that feldspar displays a certain degree of ion exchange and owns a feature of channel structure under both high and low temperatures. At high temperature, Na+ can enter the channels of feldspars. The content of Na2O in feldspar increases up to 15.9%. At middle temperature, Pb2+ can also enter the channels of feldspar as the result of ion exchange, leading thus to the formation of Pb-feldspar. At room temperature, about 97.94% Cd2+ can be removed and Cd-feldspar can be obtained. These phenomena indicate typical effects of ultra-microchannels of feldspar, which may be suggested as a potential for the treatment of heavy metal pollution and nuclear waste. The ultra-microchannels of natural minerals have played special role in migration and exchange of geomaterials. The molecular sieves of microchannels of a few natural minerals have the property of purifying molecular gas pollution. And the ionic sieves of ultra-microchannels of most natural minerals can purify ionic water contaminates.

    • Structural Evolvement of Heating Treatment of Mg/AI-LDH and Preparation of Mineral Mesoporous Materials

      2006, 80(2):170-174.

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      Abstract:Although hydrotalcite, or layered double hydroxides (LDHs), is not a common mineral, it is an important material that can be easily synthesized in laboratory. In this study, structural evolvement and BET surface area changes of heat treated Mg/AI-LDH is evaluated by XRD, TEM and N2-BET analyses. The results indicate that the magnesium-aluminum LDH with carbonate as interlayer anion, periclase-like oxides was formed at temperatures of 400-800℃. Meanwhile, 2-3 nanometer mesoporous were formed during decomposition of LDH. However, the heat treated samples still preserve the morphology of the original LDH plates. Periclase-like formed from LDH heat treatment may re-hydrolyze and recover the structure of LDH. However, crystallinity of the recovered LDH is lower than that of the original LDH. This heat treatment will result in formation of (Mg, Al)-oxide nano-crystals and nanopores among the nano-crystals. When heating temperature exceeds 1000, the periclase-like (Mg, Al)-oxide is transformed into a composite with periclase (MgO) and spinel phases. The periclase can be re-hydrolyzed and dissolved in HCl solution. After acid treatment, the sample with a high surface area is composed of spinel nano-crystals and nanopores among them. Our results will provide a new and economic way to synthesize mesoporous materials through pathways of phase transformation of precursor materials with different composition.

    • Synthesis of Pb-Feldspar by Ion Exchange Reaction and Its Implications

      2006, 80(2):175-179.

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      Abstract:Feldspar and Pb(NO3)2 were mixed and reacted at T=380℃ to synthesize Pb-feldspar. In the XRD (X-ray diffraction) pattern of the product, the d values (crystal lattice spacing) of the five peaks are 0.654, 0.342, 0.332, 0.327 and 0.257 nm. The XPS analysis results show that the binding energy of Pb 4f(7/2) in the feldspar was between 137.81-138.03 eV. Pb^2+ can replace alkali and alkali earth cations in the feldspar structure through ion exchange reaction to form Pb-feldspar.

    • Porous Properties of Nano-fibriform Silica from Natural Chrysotile

      2006, 80(2):180-184.

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      Abstract:With the TEM and physical gas adsorption techniques, porous properties of nano-fibriform 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 nanofiber. 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. Nano-fibriform silica proves better than the traditional silica as a carrier of catalyzer and a filler for reinforce rubber and plastics.

    • Decomposition of Polycyclic Aromatic Hydrocarbon (PAHs) on Mineral Surface under Controlled Relative Humidity

      2006, 80(2):185-191.

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      Abstract:The fate of Polycyclic Aromatic Hydrocarbons (PAHs) residing in the atmosphere has received enormous attention in recent years due to their mutagenic and carcinogenic risks on human health. In this context, the stability of pyrene (as a representative PAHs) on quartz, alumina, montmorillonite, kaolinite, humic acid and quartz coated with sorbed humic acid was investigated at controlled relative humidity (RH: i.e. 5% and 30%) without light irradiation in order to detect the presence of catalytic effect of mineral surface on PAHs decomposition. The stability of pyrene was found to depend strongly on the physicochemical properties of the substrates. Quartz showed a strong catalytic effect for the decomposition of pyrene even though it was coated with sorbed humic acid. Pyrene sorbed on montmorillonite and humic acid remained stable during the experimental period (i.e. 3 days). Moisture in the experimental cell also affected the stability of pyrene in particular minerals. Especially, pyrene sorbed on alumina was rapidly decomposed at higher RH. However, there were almost no effect in the case of quartz, kaolinite and humic acid. Depending on the physicochemical properties of aerosols and RH, PAHs associated with minerals in the atmosphere would be decomposed and/or stably reside in the atmosphere.

    • Adsorption of Pentachlorophenol onto Oxide and Clay Minerals: Surface Reaction Model and Environmental Implications

      2006, 80(2):192-199.

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      Abstract:The adsorption of pentachlorophenol (PCP) onto quartz, kaolinite, illite, montmorillonite and iron oxides has been investigated by batch equilibrium techniques. The pH-dependent isotherms are curves with peak values, the position of which is at about pH = 5-6 depending on the mineral species. Based on distribution of both speciation of surface hydroxyls on minerals and PCP in solution a surface reaction model involving surface complexation and surface electrostatic attraction is presented to fit the pH-dependent isotherms, and both reaction constants are calculated. The results show that on quartz and phyllosilicate minerals the predominant adsorption reaction is surface complexation, meanwhile both of surface electrostatic attraction and surface complexation are involved on the iron oxide minerals. The reaction constants of surface electrostatic adsorption are usually one to three orders in magnitude, larger than that of surface complexation. The concentration-dependent isotherms can be well fitted by Langmnir equation with the correlation coefficient R〉0.93 for kaolinite and iron oxides. The maximum adsorption is found in the order: hematite 〉 lepidocrocite 〉 goethite 〉 kaolinite 〉 quartz 〉 montmorillonite ≈ illite, which can be interpreted by consideration of both reaction mechanism and surface hydroxyl density. The significant adsorption of PCP onto mineral surfaces suggests that clay and iron oxide minerals will play an important role as HIOCs are adsorbed in laterite or latertoid soil, which is widespread in South China.

    • Absorption of Arsenite on Several Iron (Hydro-)Oxides and Impact from Pre-processing Methods

      2006, 80(2):200-205.

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      Abstract:The absorption reactions of arsenite on Fe (hydro-)oxides are studied. The three absorbent types are Fe(OH)3 gel and two Fe (hydro-)oxides, in which the Fe(OH)3 gel was dried in a microwave oven under vacuum at 80℃. It is found that pH changes from 9.71 to 10.36 in 6 minutes after the Fe (OH)3 gel was mixed with NaAsO2 solution, as the arsenite replaces the OH- in goethite and Fe(OH)3. At the 40th minute after the start of the reaction, pH decreases, which is most probably because that the monodentate surface complex of absorbed arsenite has changed into mononuclear-bidentate complex and released proton. The decline in pH values indicates not the end of the absorption but a change in the reaction type. Temperature and dissolved gas has little effect on these two types of reactions. The total absorption of arsenite increases after the absorbent is irradiated with ultrasound, which also lead to difficulty in separating the solids from solution. The absorption capacity for arsenite of Fe(OH)3 gel dried in a microwave oven under vacuum is 53.18% and 17.22% respectively better than that of Fe (OH)3 gel and gel dried at 80℃. The possible reasons are that the water molecules in the gel vibrates with high frequency under the effect of microwave irradiation, thereby producing higher porosity and improved surface activity.

    • Surface Acidity of Amorphous Aluminum Hydroxide

      2006, 80(2):206-211.

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      Abstract:The surface acidity of synthetic amorphous Al hydroxide was determined by acid/base titration with several complementary methods including solution analyses of the reacted solutions and XRD characterization of the reacted solids. The synthetic specimen was characterized to be the amorphous material showing four broad peaks in XRD pattern. XRD analyses of reacted solids after the titration experiments showed that amorphous Al hydroxide rapidly transformed to crystalline bayerite at the alkaline condition (pH>10). The solution analyses after and during the titration experiments showed that the solubility of amorphous aluminum hydroxide, Ksp=aAl3+/aH+3 , was 1010.3. The amount of consumption of added acid or base during the titration experiment was attributed to both the protonation/deprotonation of dissolved Al species and surface hydroxyl group. The surface acidity constants, surface hydroxyl density and specific surface area were estimated by FITEQL 4.0.

    • Adsorption of Ammonium and Heavy Metal Ions on Industrial Vermiculite from the Yuli Mine in Xinjiang, China

      2006, 80(2):212-218.

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      Abstract:The present work discusses the mineralogy, saturated adsorption of ammonium and adsorption of heavy metal ions (Cu2+, Pb2+ and Zn2+) on industrial vermiculite samples from the Yuli Mine in Xinjiang Autonomous Region. The saturated adsorption capacity of ammonium and the affection factors of adsorption of Cu2+, Pb2+ and Zn2+ are discussed on the basis of the mineralogical characteristics of the industrial vermiculite samples. The saturated adsorption capacities of ammonium are between 56.02 and 98.42 mmol/100g. The time of adsorption equilibrium is about 30-60 min. and the pH values and concentration of the ion solution significantly affect the adsorption capacities of the heavy metal ions. The adsorption capabilities of the heavy metal ions on industrial vermiculite are almost the same in the low ion concentration solutions, characterized by a sequence of Zn2+>Pb2+>Cu2+ for adsorption capacity in solutions with relatively high ion concentration. The results have practical significance for the application of the industrial vermiculite to treating wastewater containing ammonium or heavy metal ions.

    • Heavy Metal Removal from Water by Adsorption Using Pillared Montmorillonite

      2006, 80(2):219-225.

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      Abstract:Removal of Cu2+, Cr3+ and Cd2+ from aqueous solutions by adsorption on montmorillonite modified by sodium dodecylsulfate (SDS) and hydroxy-alumino-silicate (HAS) was investigated. Experiments were carried out as a function of solution pH, solute concentration, and time. The Langmuir model was adopted to describe the single-solute adsorption isotherm, in which the Langmuir parameters were directly taken from those obtained in single-solute systems. The kinetics of metal ions adsorption was examined and the pseudo-first-order rate constant was finally evaluated.

    • Effects of Pb~(2+), Cd~(2+) and Cu~(2+) on the Aqueous Zn~(2+) Sorption by Hydroxyapatite

      2006, 80(2):226-229.

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      Abstract:In this paper, the behaviors of aqueous zinc sorption by hydroxyapatite in the co-existence of Pb2+, Cd2+ and Cu2+ are investigated, the effects of Pb2+, Cd2+ and Cu2+ on the sorption of Zn2+ are discussed, and the hydroxyapatite sorption capabilities for Pb2+, Cd2+, Cu2+ and Zn2+ are compared. The experimental results show that the Zn2+ removal efficiency decreases gradually with the increase of the Cd2+ concentration of the solution, and there is no sorption preference between Cd2+ and Zn2+. On the other hand, the Zn2+ removal efficiency rapidly decreases rapidly with the increase of the Cu2+ concentration of the solution, and there is a clear sorption preference between Cu2+ and Zn2+. It is noticed that the Zn2+ removal efficiency is hardly changed with the variance of Pb2+ concentration because the removal mechanisms for these two ions are totally different. It is concluded that the adsorption affinities of the heavy metals for the hydroxyapatite follows this sequence: Pb2+> Cu2+> Cd2+> Zn2+.

    • Mineralogical and Geochemical Constraints on Arsenic Mobility in a Philippine Geothermal Field

      2006, 80(2):230-235.

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      Abstract:Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe-hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range ofpH and redox conditions.

    • Adsorption Kinetics of Methylene Blue from Aqueous Solutions onto Palygorskite

      2006, 80(2):236-242.

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      Abstract:The adsorption kinetics of methylene blue from aqueous solutions on purified palygorskite was investigated. The kinetics data related to the adsorption of methylene blue from aqueous solutions are in good agreement with the pseudo-second order equation in ranges of initial concentration of 120-210 mg/L, oscillation speed of 100-200 r/min and temperature of 298-328K. The experimental results show that methylene blue is only adsorbed onto the external surface of purified palygorskite, and the apparent adsorption activation energy is 13.92 kJ/mol. The relatively low apparent adsorption activation energy suggests that the adsorption of methylene blue involves in not only a chemical, but also a physical adsorption process, and it is controlled by the combination of chemical adsorption and fiquid-film diffusion.

    • Diffusion Kinetics of Carbonate Hydroxyapatite (CHAP) for Adsorbing F~- Dissolved in Water

      2006, 80(2):243-248.

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      Abstract:A systematic research was performed about diffusion kinetics of adsorbing F- dissolved in water for carbonate hydroxyapatite (CHAP) from the natural hydroxyapatite which was modified by adulterating with CO32-. The result shows that the speed of F- adsorption is controlled by membrane diffusion when F- concentration is relatively low, which is expressed by the kinetic equation of diffusion Q=0.0005(Ci-C)(t-ti)+0.3967, or by vacancy diffusion when F- concentration is relatively high, which is expressed by the kinetic equation of diffusion ln[C(o, t)]=8.4718-0.5048lnt. Based on the feature of CHAP for adsorbing F- dissolved in water and its special channel of the structure of CO32- modified hydroxyapatite, models of vacancy diffusion and membrane diffusion were established.

    • Oxidation of As^Ⅲ by Several Manganese Oxide Minerals in Absence and Presence of Goethite

      2006, 80(2):249-256.

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      Abstract:Oxidation of As^Ⅲ by three types of manganese oxide minerals affected by goethite was investigated by chemical analysis, equilibrium redox, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Three synthesized Mn oxide minerals of different types, birnessite, todorokite, and hausmannite, could actively oxidize As^Ⅲ to Asv, and greatly varied in their oxidation ability. Layer structured birnessite exhibited the highest capacity of As^Ⅲ oxidation, followed by the tunnel structured todorokite. Lower oxide hansmannite possessed much low capacity of As^Ⅲ oxidation, and released more Mn^2+ than birnessite and todorokite during the oxidation. The maximum amount of Asv produced during the oxidation of As^Ⅲ by Mn oxide minerals was in the order: birnessite (480.4 mmol/kg) 〉 todorokite (279.6 mmol/kg) 〉 hansmannite (117.9 mmol/kg). The oxidation capacity of the Mn oxide minerals was found to be relative to the composition, crystallinity, and surface properties. In the presence of goethite oxidation of As^Ⅲ by Mn oxide minerals increased, with maximum amounts of Asv being 651.0 mmol/kg for birnessite, 332.3 mmol/kg for todorokite and 159.4 mmol/kg for hansmannite. Goethite promoted As^Ⅲ oxidation on the surface of Mn oxide minerals through adsorption of the Asv produced, incurring the decrease of Asv concentration in solutions. Thus, the combined effects of the oxidation (by Mn oxide minerals)-adsorption (by goethite) lead to rapid oxidation and immobilization of As in soils and sediments and alleviation of the As^Ⅲ toxicity in the environments.

    • Study on Decoloration of Acidic Scarlet GR by Pyrolusite Oxidation under an Acid Condition

      2006, 80(2):257-261.

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      Abstract:Decoloration of acidic scarlet GR by pyrolusite is studied in this paper. The effects of pH in solution, dosage and granularity of pyrolusite, reaction temperature, and vibration speed on decoloration efficiency are discussed. According to experiment results, the decoloration efficiency may exceed 95% for 40 mg/L GR solution by pyrolusite, pH is most important among all factors which impact the decoloration of acidic scarlet GR. Dosage and granularity of pyrolusite, reaction temperature, and vibration speed have a little benitfit on decoloration. The high decoloration efficiency and low removal efficiency of COD as well as FT-IR spectra of products between pyrolusite and acidic scarlet GR indicate that acidic scarlet GR undergoes the redox reaction on the interface of mineral and its chromophore is oxidated and decolored, but it is not removed thoroughly by oxidation.

    • Impact Factors on Removal of Perchloroethylene with Nano-Ni/Fe Methodology

      2006, 80(2):262-266.

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      Abstract:Chlorinated hydrocarbons are widely detected in groundwater, but conventional removal methodologies are not time-and-cost effective. With the development of iron reducing technology in recent years, research on nano-iron and nano-bimetal has become a hot spot. The paper presents the results of impact factors on perchloroethylene (PCE) removal by nano-Ni/Fe method. The data show that the reaction rate of unexposed nano-Ni/Fe is 4 times higher than exposed one; and temperature is one of the important controlling factors. Reaction rate constant KSA increases by 2-3 times with every 10℃ increment of temperature. Within a specific range, higher Ni/Fe ratio favors dechlorination process. When the Ni/Fe is 8%, the dechlorination process reaches the highest rate. Dissoved oxygen in the solution does not favor the degradation of chlorinated hydrocarbons.

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

      2006, 80(2):267-272.

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      Abstract: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.

    • Synthesis and Photocatalytic Activity of Ti-pillared Bentonite

      2006, 80(2):273-277.

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      Abstract:Ti-pillared bentonite has been successfully prepared using a modified method that can induce the transformation of TiO2 pillar from amorphous to anatase phase at a low temperature (150℃). The value of d0.01 =1.94 nm obtained by Ti-pillared bentonite is larger than that of corresponding raw clay (1.56 nm). Due to large numbers of Ti-pillars formed, the Ti-pillared bentonite shows an excellent ability in adsorbing Rhodamine B (RB). The photocatalytic activity and kinetic equation are investigated by decomposing RB solution under the UV irradiation. It is found that the Ti- pillared bentonite shows super photocatalytic activity for the degradation of RB solution compared with the untreated bentonite and pure TiO2, and the kinetic equation of the degradation of RB solution is a 1.5-oder equation.

    • Microstructure and Photocatalytic Decomposition of Methylene Blue by TiO2-Mounted Halloysite, a Natural Tubular Mineral

      2006, 80(2):278-284.

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      Abstract:On the basis of analysis of structure and properties, halloysite, a natural tubular mineral, was developed for an environmental treatment. TiO2 was mounted into halloysite by using hydrolysis of tetrabutyl titanate at room temperature. The adsorption and photocatalytic performance of halloysite and TiO2-mounted halloysite have been examined in methylene blue aqueous solution in the dark and under ultraviolet ray irradiation, respectively. Their performance of adsorption and photodecomposition was evaluated from the adsorbed and degraded amounts of methylene blue (MB). Due to the mixture of adsorption and photodecomposition, the concentration of MB, organic pollution, in water decreased rapidly with TiO2-mounted halloysite powder, which is a faster reaction than that with halloysite-only adsorption. This new use of halloysite is leading to many interesting applications in the decomposition and elimination of various pollutants in air and water.

    • Absorption and Photocatalytic Degradation of Machine Oil by Exfoliated Graphite-Supported Nanometer TiO2 Material

      2006, 80(2):285-289.

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      Abstract:By loading nanometer anatase onto exfoliated graphite with the sol-gel method, exfoliated graphite-TiO2 composite (EG-TiO2) can be prepared, which can adsorb oil and can also degrade oil. In a technologic condition for preparing EG-TiO2, the impregnated number of times is the most important factor to influence oil-adsorbing capability, that is, when the impregnated number of times increases, the amount of saturation-adsorbed oil decreases. The study of EG-TiO2 photocatalytic degradation of machine oil based on the weight-loss method and infrared spectrum method indicates that EG-TiO2 has obvious effect of photocatalytic degradation for machine oil. Its performance is superior to pure nanometer TiO2 powder because nanometer TiO2 in EG-TiO2 has three-dimension laminar structure and comparatively high adsorption capability.

    • Hydrothermal Formation of Lath-Shaped Trioctahedral Smectite with High Crystallinity

      2006, 80(2):290-295.

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      Abstract:Lath-shaped and highly crystalline trioctahedral smectites were synthesized under hydrothermal conditions. The quenched glasses with stoichiometrically dehydrated Na-smectite compositions were treated at (a) 500℃ and 100 MPa for 1 and 11 days; and (b) 300℃ and 100 MPa for 7 days. The crystallinity and particle size of products were dependent on the chemical composition of the starting glass, synthetic temperature and duration of hydrothermal treatment. The high structural ordering and large dimensions of the products were confirmed from the sharpness of XRD peaks; and hydration behavior under controlled relative humidity. Transmission electron microscopy was also performed for the characterization of the particle size of product. Particle sizes vary from ca. 10 nm to a few pm by changing the chemical compositions of the starting materials. The product with the highest structural ordering and largest dimension was obtained from Nao.33(Mg1.83Al0.67)Si4O11 glass treated at 500℃ and 100 MPa for 1 day. The obtained results also confirmed the metastability and compositional dependency in the formation of highly crystalline trioctahedral smectite at hydrothermal conditions.

    • Experimental Study on Formation Conditions of Ammoniojarosite and Its Environmental Significance

      2006, 80(2):296-301.

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      Abstract: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.

    • Abstracts of Acta Geologica Sinica (Chinese Edition) Vol. 80, No. 3, 2006

      2006, 80(2):302-308.

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      Abstract:Differential Salt Tectonic Deformation and Segmentation of the Kuqa Foreland Fold-Thrust Belt, Tarim Basin, Northwest China TANG Liangjie, LI Jingchang, YU Yixin, WANG Qinghua, YANG Wenjing, XIE Huiwen, CHEN Shuping and PENG Gengxin (Key Laboratory for Hydrocarbon Accumulation, China University of Petroleum, Ministry of Education, Beijing 102249; Basin & Reservoir Research Center, China University of Petroleum, Beijing 102249; Department of Earth Resources Engineering, Kyushu University, Japan; 4. Tarim Oilfield Company, PetroChina Company Ltd., Korla, Xinjiang 841000; 5.

    • Abstracts of Acta Geologica Sinica (Chinese Edition) Vol. 80, No. 4, 2006

      2006, 80(2):309-313.

      Abstract (1024) HTML (0) PDF 0.00 Byte (88) Comment (0) Favorites

      Abstract:Natural Environment during the Living Period of Early Human and Gigantic Ape in West Hubei CHENG Jie, ZHENG Shaohua, GAO Zhenji, ZHANG Zhaoqun, FENG Xiaobo, and WANG Xiaoning (School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083; Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Science, Beijing 100044; Department of Urban and Environment, Peking University, Beijing 100871; Institute of Cultural Relics and Archaeology of Hubei Province, Wuhan, Hubei 430077; Enshi Museum, Enshi, Hubei 445000)

    • Editorial Comment

      2006, 80(2):314-314.

      Abstract (1092) HTML (0) PDF 0.00 Byte (90) Comment (0) Favorites

      Abstract:Environmental mineralogy is having an unprecedented development in the world. Following the increasing communications between scholars on environmental mineralogy, the number of papers on this subject is rising progressively. Besides, the cultivation of talents has been strengthened. And some colleges found graduate schools or research centers of environmental mineralogy. The Special Group of Environmental Mineralogy was set up in the Commission on Mineralogy, Geological Society of China in April 1999. The Commission on Environmental Mineralogy was set up in the Chinese Society for

Chief Editor:HOU Zengqian

Governing Body:China Association for Science and Technology

Organizer:Geological Society of China

start publication :1922

ISSN:ISSN 1000-9515

CN:CN 11-2001/P

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