Advanced Materials Research Vols. 455-456

Abstract: Photodegradation of p-nitrophenol catalyzed by ZnO/MWCNTs composite in water was investigated. The effects of pH, irradiation time, catalyst loading, initial substrate concentration and MWCNTs content on the degradation were investigated. Experiment results revealed that the optimal conditions were a p-nitrophenol concentration of 60.0 mg/L at pH 5.0 with catalyst loading of 10.0 g/L under solar irradiation for the illumination of 180 min. The highest efficiency on photodegradation of p-nitrophenol can be achieved with an optimal MWCNTs/ZnO mass ratio of 0.16%. Possible decomposing mechanisms were also discussed. The repeatability of photocatalytic activity was tested. The photocatalyst was used ten cycles with degradation efficiency still higher than 95%. The results of the study showed the feasible and potential use of ZnO/MWCNTs composite in degradation of toxic organic pollutants.

Abstract: The Dachang tin-polymetallic ore deposit is one of the largest Sn ore deposit in the world. For a long time, the Danchi mineralization belt was studied from different perspective, i.e., the mineralization age, the ore source, the deposit model, etc. In fact, the contradistinction of the three mineralization belts has an important macroscopic significance for deepen the genetic mechanism of the Danchi mineralization belt. In the Changpo ore deposit of the west mineralization belt, besides three δ³⁴S values (+4.794, +2.31, +2.6), the δ³⁴S values belong to negative value, yet in the Lamo ore deposit of the middle mineralization belt, most of the δ³⁴S values show positive besides two sulfur isotope sample (δ³⁴S=－0.36, －1.6). But in the Dafulou ore deposit of the east mineralization belt, the δ³⁴S values range from negative value to positive value. So there are only same ore resource partly for the Lamo ore deposit and the Changpo ore deposit. Overall, the ore source of the Dafulou ore deposit is more extensive than other ore deposit, and shares the same ore source with the other ore deposit.

Abstract: The Danchi mineralization belt is an important ore district in southern China. According to the tectonic characteristics, the Danchi mineralization belt could be devided into three mineralization belts, such as the east mineralization belt, the west mineralization belt and the middle mineralization belt. The Dafulou deposit, which belongs to the east mineralization belt, is located in the eastern flank of the NNW–SSE-trending Danchi anticlinorium. The key structures in the Dafulou ore district are the NW-trending faults, which developed parallel with the axis of the Dachang anticlinorium. In the Dafulou ore district, the Devonian stratum has a closed contact with the Sn–polymetallic deposits. In the Danchi mineralization belt, the granite belongs to alkali-calcium rock series or near to the alkali rock series. There are four different types of hydrothermal alteration, including silicification, carbonation, pyritization and pyrrhotitezation.

Abstract: The best catalytic capacity of Nd-doped Ti/SnO2-Sb2O5 electrodes was obtained by sol-gel preparation. Nd-doped Ti/SnO2-Sb2O5 coating was characterized using technique such as scanning electron microscopy (SEM), and X-ray diffraction (XRD). Nd-doped electrode fragments looks smaller, more compact and more uniform than undoped electrode through SEM. The crystal cell’s average diameter of Nd-doped electrodes was 3.48nm through XRD. BOD5/COD of Reactive Brilliant Red X-3B increased 200% under optimum conditions after 1h electrolysis. Instantaneous current efficiency (ICE) was 51.15 % in first 40 min, 35.73 % in first 60 min. In the first 40 minutes of electrolysis process, COD of Reactive Brilliant Red X-3B changes conformed to the pseudo first-order kinetic equation. Electrical Properties Tests showed that the oxygen evolution potential values of Nd-doped electrodes were higher than the undoped electrodes in various media.

Abstract: This paper investigates the differences in the temporal heterogeneity of soil moisture between natural restoration ecosystem without disturbance (named as eco-1), restoration ecosystem with disturbance (named as eco-2) and shrubs ecosystem (named as eco-3) in red soil hillside fields. The probe soil moisture measured at 20 and 40 cm below the soil surface Hydrosense Portable Time Domain Reflectometry (TDR) system. The results showed that: (1) Daily measurements during a growing season showed significantly temporal interactions between vegetation and water. Soils under eco-2 (restoration ecosystem with disturbance) and eco-3 (shrubs ecosystem) were wettest at the start of the growing season but dries at the end; (2) The coefficient of variation of soil moisture content over time during the growing season was significantly higher in eco-2 than in eco-1, and at two depths beneath the soil surface (20 and 40 cm).

Abstract: Caixiashan Pb-Zn deposit is the largest Pb-Zn deposit discovered in the middle Tianshan area. Examples of Carboniferous magmatic and tectonic activity are widely distributed. The ore bodies are controlled by EW trend faults, based on field observations. The main ore minerals are galena, sphalerite, pyrrhotite, pyrite and chalcopyrite, while quartz, sericite and calcite are the main alteration minerals. The ore also exhibits minerals zoning. In addition, the wide range of S isotopic composition, high temperature and moderate salinity of fluid inclusions, and good correlation of ore and wall rock Pb isotopes together with H, O, C isotopic compositions indicate mixing of magmatic origin and upper sedimentary rocks. Combined with high concentration of pyrite and pyrrhotite and some argentite, the Pb-Zn deposit may be controlled by the Hercynian orogeny, which controlled the EW-NEE faults and Carboniferous igneous rocks. The faults provided the channel for fluid transport and the igneous rocks provided heat and main source of the metals. When the fluid passed through metal-bearing rocks, it extracted Pb, Zn, Ag etc.. Interaction of the metal-bearing fluid with the brecciated and fractured marble caused the metals to be deposited. Thus the Caixiashan Pb-Zn deposit is a fault-controlled hydrothermal deposit.

Abstract: In order to investigate the dissolution-releasing characteristics of the pollutants in coal gangue, this article carries out soaking experiment of coal gangue in different wind erosion degree of XINQIU strip mine under different conditions. The results show that the main dissolution releasing pollutants of the coal gangue are total hardness (CaCO₃), sulfate (SO₄^2-), natrium (Na⁺), total dissolved solid (TDS), fluoride (F^-), COD_Mn, and total iron (Fe). Chloride (Cl^-), manganese (Mn) and zinc (Zn) occur in small quantities and heavy metals and arsenic (As) in trace concentration. The pH scale is nearly neutral. The higher the wind erosion degree is, the larger the quantity of the inorganic pollutants released by the gangue is. The quantity of the inorganic pollutants released by mixed coal gangue in high wind erosion degree inside the mountaintop is larger. Fluoride (F^-), oxygen consumed (OC), and total Fe are released by fresh mixed coal gangue in higher concentration. Soaking time, solid-to-liquid ratio, acidity, granularity and stirring have a significant impact on the dissolution-releasing of the pollutants. The longer the soaking time, the smaller the solid-to-liquid ratio, the stronger the acidity, the smaller the granularity and the faster the stirring intensity is, the quicker the rate of the pollutants dissolution-releasing is and the larger the total quantity of the pollutants is. Which can accelerate the dissolution-releasing of the pollutants which is controlled by diffusion.

Abstract: In this paper, treatment and reuse of wastewater generated from Pb-Zn sulfide Ore flotation with butyl xanthate and amino dithiophosphate as collectors were studied respectively. The impact of directly reused wastewater on galena flotation was investigated. The results indicate that lower recovery was achieved when the wastewater was directly reused in the process of galena flotation whereas 90% of recovery was achieved as the wastewater was treated by ozone, activated carbon and resins before reusing.

Abstract: With the water supplies shortage and the change of national standards for arsenic requirements from 0.05 mg/L mentioned to 0.01 mg/L, a investigating for 72 water Wells in zhengzhou northern suburb has been far-reaching significance and urgent to clarify the situation of arsenic overweight. Firstly, the main reasons which lead to the arsenic pollution by natural sources or human activity have been demonstrated briefly. Then the monitoring history records for source Wells of arsenic levels excessive have been analyzed, by which a arsenic distribution map for the north suburb Wells has been painted. Furthermore, based on the map, sampling tests for typical Wells have been carried out simultaneously. Through the comparison, it is concluded : type C Wells whose depth is between 270.84 to 341 meters have no arsenic overweight. But type A and B whose depth is between71.7 to 92 meters has a serious arsenic overweight ,in which the highest arsenic is 0.487 mg/L. at last, a new suburb Wells arsenic level distribution map has been drawn which provides a reliable basis for investigation on migration transform rules of arsenic in the groundwater, establishment of scheduling solution for water source of the Wells and rigging new wells in the northern suburbs.

Abstract: This paper presented the Pb-Zn deposits characteristics in southeast Chongqing. The Pb-Zn deposits occurred in Lower-Middle strata with develop the dolomites, limestones as ore-bearing host-rocks. They are veined, stratifed, stratoid, and lenticular in shape and locally pinch and swell with dominant ore minerals of sphalerite, galena, and pyrite . the Pb-Zn ore deposits grade changed from 0.32% to 7.06% for Pb and 4.21% to 14.29% for Zn. The Gaodongzi orebody has highest concentrations of Pb with 7.06% record and Zn with 14.29% record. The tectonic setting, ore-host rocks, wall-rock alternation, and mineral composition will control the Pb-Zn deposits distribution in Chongqing area.