Study on the Antagonistic Potential of Biosynthesized Hematite Nanoparticles During Water and Wastewater Treatment     

Marwa Eltarahony  Sahar Zaki  Zeinab Kheiralla  Desouky Abd‐El‐Haleem 《洁净——土壤、空气、水》2019,47(6)

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Supported TiO2 on Kaolin,Cordierite, and Calcite for Photocatalytic Removal of Dyes from Wastewater     

Amal M. Ibrahim  Doaa M. El‐Mekkawi  Mohamed M. Selim 《洁净——土壤、空气、水》2020,48(4)

Kaolin, cordierite, and calcite are investigated as supports for TiO₂. The prepared TiO₂/support samples are examined for the removal of organic dyes from wastewater. The samples are preliminarily investigated to identify the optimal loaded system using synthetic wastewater containing methylene blue (MB). Data indicate that the investigated support significantly affects the photocatalytic activity of the supported TiO₂. Low photocatalytic activity toward MB degradation is observed upon using TiO₂/calcite when compared to the unsupported TiO₂. Interaction between calcite and titania species probably occurrs to produce the less photoactive CaTiO₃ amorphous species. Anatase TiO₂ is obtained upon using kaolin and cordierite as supports. The low photocatalytic performance of the TiO₂/kaolin sample is also observed. A high concentration of MB on TiO₂/kaolin surfaces blocks the photoactive sites. TiO₂/cordierite shows the highest photocatalytic activity compared to the unsupported TiO₂ as well as the other TiO₂/support samples. Rigid cordierite particles suppress the agglomeration of TiO₂ particles during the preparation, leading to a high exposed surface of TiO₂ towards light illumination. TiO₂/cordierite is investigated for the removal of organic dye from real wastewater collected from a textile dyeing factory. Color removal of up to 46% is achieved upon UV irradiation.  相似文献   

Integrated coastal zone management programme northwest African region case     

Maria Snoussi  El Hafid Tabet Aoul   《Ocean & Coastal Management》2000,43(12):1033-1045

The development of industrial and tourism activities as well as the increase in the urban population in the northwest African region has generally been highly concentrated in the coastal zone. Due to high rates of population growth, urbanisation is likely to increase dramatically in the coming future. This paper presents a physical and socio-economic environmental analysis of the region and highlights the few efforts that have called for the development of co-ordinated strategies in view of integrated coastal zone management. Experience in the implementation of methodologies for adopting integrated coastal zone management strategies in these countries is discussed.  相似文献   

Strontium as a tracer of weathering processes in a silicate catchment polluted by acid atmospheric inputs, Strengbach, France   总被引：4，自引：0，他引：4  

A. Probst  A. El Gh''mari  D. Aubert  B. Fritz  R. McNutt   《Chemical Geology》2000,170(1-4):203-219

This paper determines the weathering and atmospheric contributions of Ca in surface water from a small spruce forested silicate catchment (N–E France) receiving acid atmospheric inputs. The bedrock is a granite with K-feldspar and albite as dominant phases. The calcium content in plagioclase is low and the Ca/Na ratio in surface water is high, reflecting other sources of calcium from those expected from the weathering of major mineral phases. The biotite content is low. Only traces of apatite were detected while no calcite was found in spite of a major hydrothermal event having affected the granite. The strontium isotopic ratio ⁸⁷Sr/⁸⁶Sr and Sr content was used as a tracer of weathering and was determined in minerals and bulk bedrock, open field precipitation, throughfall, soil solution, spring and stream water. The Sr isotopic ratio of the reacting weathering end-member was predicted by simulating the alteration of the granite minerals by incorporating strontium into the water–rock interaction kinetic code KINDIS. In the early stages of water–rock interaction, K-feldspar and biotite strongly influence the isotopic composition of the weathering solution whereas, the Na-rich plagioclase appears to be the main long-term reactive weathering end-member. Approximately 50% of dissolved Sr in streamwater are atmospherically derived. The ⁸⁷Sr/⁸⁶Sr ratios of exchangeable Sr in the fine fraction at 1-m depth from a soil profile indicate that the amount of exchangeable Sr seems essentially controlled by atmospheric inputs. The exception is the deep saprolite where weathering processes could supply the Sr (and Ca). Na-Plagioclase weathering obviously control the chemistry and the isotopic composition of surface waters. The weathering of trace mineral plays a secondary role, the exception is for apatite when plagioclase is absent. Our hydrochemical, mineralogical and isotopic investigations show that a major part of the strong Ca losses detected in catchment hydrochemical budgets that result from the neutralization of acid precipitation has an atmospheric origin. Consequently, in the long term, in such areas, the availability of such an exchangeable base cation might be strongly limited and surface waters consequently acidified.  相似文献   

Geochemistry of ultrabasic and associated bodies in the Eastern Desert,Egypt     

E.M. El Shazly  M.H. Hatout 《Precambrian Research》1982,16(4):A57-A58

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Two orogenies in the Meatiq area of the Central Eastern Desert,Egypt     

Mohamed E. Habib  A.A. Ahmed  Osman M. El Nady 《Precambrian Research》1985,30(2):83-111

The Pan-African basement exposed in the Meatiq area west of Quseir, Egypt, consists of an infracrustal basement overthrusted by a supracrustal cover. The infracrustal rocks were developed as a result of an old orogeny referred to as the Meatiqian orogeny where granite—gneiss, migmatitic gneisses and migmatized amphibolites were formed. The granite—gneiss represents a deformed granite pluton emplaced at 626±2 Ma, whereas the migmatitic gneisses and amphibolites are of mixed igneous and sedimentary parentage. In view of the data so far available, the nature of the Meatiqian orogeny could not be deciphered. In spite of the young isotopic ages, it is suggested that at least the metasedimentary gneisses represent older rocks in the stratigraphic sequence of the infracrustal basement.The supracrustal cover represents a part of an extensive ophiolitic mélange obducted onto the infracrustal basement during the next orogeny (Abu Ziran orogeny) which culminated at 613±2 Ma. An active continental margin-type regime can adequately explain the evolution of such a supracrustal cover. During obduction, the ophiolitic mélange and the upper 2 km thick part of the infracrustal basement were intensely deformed and metamorphosed under PT conditions of the greenschist—epidote amphibolite facies. The deformed infracrustal basement was converted into mylonitic—blastomylonitic rocks and schists composing five thrust sheets, and subsequently intruded by synkinematic granitoid sheets. Later, both the infracrustal basement and the overlying supracrustal cover were isostatically uplifted, subjected to complex shallow folding giving rise to the major Meatiq domal structure, and were intruded by a postkinematic adamellite pluton at 579±6 Ma.  相似文献   

Padé approximants for radiative transfer in inhomogeneous medium     

S. A. El Wakil  M. H. Haggag  H. M. Machali  E. A. Saad 《Astrophysics and Space Science》1983,91(1):125-131

The Padé approximants is used to estimate the albedo for an inhomogeneous semi-infinite medium. The single-scattering albedo is assumed to fall off exponentially with optical depth.  相似文献   

Two forsterite-bearing FUN inclusions in the Allende meteorite     

Robert N. Clayton  Glenn J. MacPherson  Ian D. Hutcheon  Andrew M. Davis  Lawrence Grossman  Toshiko K. Mayeda  Carol Molini-Velsko  John M. Allen  Ahmed El Goresy 《Geochimica et cosmochimica acta》1984,48(3):535-548

We have discovered two FUN inclusions, CG-14 and TE, among a group of five forsterite-rich inclusions in Allende, two of which are described for the first time herein. All five consist of euhedral forsterite and spinel crystals poikilitically enclosed by fassaite. Forsterite and spinel are usually segregated from one another, sometimes into a spinel-rich mantle and a forsterite-rich core. Some inclusions contain vesicles, indicating that they were once molten. The crystallization sequence inferred from textures is: spinel, forsterite, fassaite and, finally, Mg-rich melilite. One concentrically-zoned inclusion contains melilite in its mantle whose composition lies on the opposite side of the liquidus minimum in the melilite binary from that in its core. This suggests that segregation of forsterite from spinel in all of these inclusions could be due to volatilization of MgO and SiO₂ relative to Al₂O₃ and CaO from the outsides of droplets. CG-14 is relatively uniformly enriched in refractory elements relative to Cl chondrites by a factor similar to that for Ca-, Al-rich coarse-grained inclusions except for Ca, Al and Hf which are unusually low. No Ce anomaly such as found in FUN inclusions Cl and HAL is present in CG-14. Whole-rock samples of CG-14 and TE are more strongly mass-fractionated in oxygen relative to “normal” Allende inclusions than the FUN inclusion EK 1-4-1 and less so than Cl. Relative to bulk Allende, both inclusions have strongly massfractionated magnesium and silicon and ²⁵Mg excesses or deficits of ²⁴Mg or ²⁶Mg. CG-14 has a ²⁹Si excess or a deficit of ²⁸Si or ³⁰Si. Volatilization loss cannot be responsible for the magnesium and silicon isotope fractionations, as this would require prohibitively large mass loss from these magnesium-rich inclusions. The remarkable similarity in textures between FUN and non-FUN inclusions implies similar thermal histories, arguing against different rates of evaporative loss of major elements. Sputtering alone may be insufficient to account for the magnitude and direction of oxygen isotope fractionation in FUN inclusions.  相似文献   

Interpretation of metal profiles in a sediment core from lake geneva: metal mobility or pollution     

Z. J. Wang  H. El Ghobary  F. Giovanoli  P. -Y. Favarger 《Aquatic Sciences - Research Across Boundaries》1986,48(1):1-17

The transition elements Mn, Fe, Co, Zn, Cu and Cr together with Pb and P were determined in three sequential extractions of sediment and in the pore water of a 35-cm sediment core from Lake Geneva. A high percentage of the mobile Mn, Fe, P, Co, Pb and Zn was extracted in the first (inorganic) fraction, whereas the mobile Cu and Cr were mostly found in the second (organic and sulfide) fraction. Mn was subject to recycling with solubilization from the surface sediment to the oxic bottom water where it was precipitated. Highly enriched Co and P values were observed in the top few mm of the sediment resulting from post depositional solubilization with upward migration and precipitation with oxi-hydroxides at the sediment surface. The slower increase of Cu, Zn and Pb concentrations towards the sediment/water interface are the result of an increase of anthropogenic sources over the past decades. A further increase in Pb in the first cm of the core is believed to be related to the freshly precipitated Mn oxi-hydroxides.  相似文献   

Use of Solute Chemistry and Isotopes to Identify Sources of Ground-Water Recharge in the Nile Aquifer System, Upper Egypt     

Mostafa A. Awad  Nahed E. El Arabi  Mokhtar S. Hamza 《Ground water》1997,35(2):223-228

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