Traitement physico-chimique d'une eau souterraine fortement chargée en fer et en manganèse

2000 ◽  
Vol 27 (4) ◽  
pp. 632-641
Author(s):  
Catherine Lessard ◽  
Donald Ellis ◽  
Jean Sérodes ◽  
Christian Bouchard
Keyword(s):  
Pilot Study ◽  
Manganese Oxides ◽  
Settling Tank ◽  
Free Chlorine ◽  
Target Area ◽  
High Concentration ◽  
Dose Ranging ◽  
Iron Manganese ◽  
Filter Bed ◽  
Iron And Manganese

Conventional greensand treatment for the removal of iron and manganese from groundwater is not quite appropriate for waters with a high content of iron and manganese. In this pilot study, different modifications to this process were tested to improve treatment performances for water with a high concentration of iron and manganese: addition of a settling tank, use of sand and anthracite covered with manganese oxides, and aeration. Different oxidants and oxidation sequences were also tested. Results show that the presence of a high quantity of iron significantly improves removal of manganese. These results also confirm that manganese oxidation can be realized with free chlorine inside a filter bed other than greensand, provided that the excess of free chlorine is sufficient. Within the conditions studied, the target area for filtration performances can be attained for every treatment sequence tested and for a filtering aid dose ranging from 0.25 to 0.5 mg/L. Although groundwater aeration leads to better settling performances, it also accelerates head loss in the filtering bed when a filtering aid is present.Key words: groundwater, iron, manganese, pilot study, treatment, separation.

Relict joints in completely decomposed volcanics in Hong Kong

1982 ◽  
Vol 19 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Y. C. Koo
Keyword(s):  
Hong Kong ◽  
Manganese Oxides ◽  
Strength Testing ◽  
Residual Soil ◽  
High Concentration ◽  
Strength Parameters ◽  
Decomposition Products ◽  
Joint Surfaces ◽  
Iron Manganese ◽  
Iron And Manganese

In a major cutting in the completely decomposed volcanics in Hong Kong, closely spaced relict joints were found throughout the residual soil. The persistence of the exposed joint surfaces varies from several centimetres to more than 10 m. The joint surfaces, which are generally smooth and sometimes slickensided, are usually coated with a thin black-brown deposit. The origin of this deposit is believed to be the precipitation of iron-manganese decomposition products that have filled the joints in the parent rock during the course of weathering. Chemical analyses carried out on typical specimens have confirmed a high concentration of iron and manganese oxides. Results of laboratory shear strength testing show that the peak strength parameters along joint surfaces and of the intact material are: c′ = 0, [Formula: see text] and c′ = 6 kPa, [Formula: see text] respectively. Analyses of joint survey data indicate that relict joint orientations occur in systematic major sets and that joint spacings roughly follow a Poisson distribution.

Microbial Community Analysis in Bio-Filter Bed of Iron and Manganese Removal Treating High Iron, Manganese and Ammonia Nitrogen Groundwater

2013 ◽  
Vol 777 ◽  
pp. 238-241 ◽  
Author(s):  
Xiao Rong Kang ◽  
Ya Li Liu
Keyword(s):  
Community Analysis ◽  
Ammonia Nitrogen ◽  
Microbial Community Analysis ◽  
High Iron ◽  
Manganese Removal ◽  
Microbial Analysis ◽  
Removal Efficiencies ◽  
Iron Manganese ◽  
Filter Bed ◽  
Iron And Manganese

The integrated process of spray aeration, falling water aeration and bio-filter bed was used for treating groundwater with high iron, manganese and ammonia nitrogen (NH4+-N). The removal efficiencies of iron, manganese and NH4+-N reached 99.1%, 95.0% and 85.2%, and corresponding effluent iron and manganese decreased to 0.1 and 0.05 mg/L. Microbial analysis results indicated that theβ-Proteobacteriawas predominant microorganisms, in whichGallionellaandLeptothrixwere main iron-removal bacteria and manganese-removal bacteria, respectively. Simultaneously,Pseudomona, belonged toγ-Proteobacteria, could absorb and oxidize free manganese to be manganese dioxide (MnO2) by extracellular oxidase.

scholarly journals Trace Elements in the Nizhne-Bureysk Reservoir Tributaries Water

2016 ◽  
pp. 15
Author(s):  
Keyword(s):  
Trace Elements ◽  
Cadmium Concentration ◽  
High Water ◽  
Aluminum Concentration ◽  
Small Rivers ◽  
Content Increase ◽  
High Concentration ◽  
Hydro Power ◽  
Iron Manganese ◽  
Iron And Manganese

Implementation of big scale projects on construction and operation of waterworks facilities is a serious factor of intervention into aquatic ecosystems functioning. The Bureya River and its tributaries water chemical composition was characterized with the results of the river water monitoring within the zone of the Nizhne-Bureysk hydro power station construction over the period of 2011-2014, and considerable variations of the small rivers’ water physical/chemical characteristics were demonstrated. Seasonal and many-year dynamics of the trace elements dissolved forms content was revealed. Higher concentrations of iron, manganese, copper, and mercury, as well as their considerable concentrations connected with the territory natural features were established. Small rivers’ waters that drain mostly effusive rocks are characterized by higher concentrations of iron and manganese while sediments are characterized by high concentration of aluminum. The seasonal and many-year character of the microelements dissolved forms is diverse and is mostly determined by the hydrological factor. In the high water 2013 a considerable increase in copper and barium runoff was registered in all tributaries while increase of aluminum concentration was found only in the Bureya, insignificant increase of the iron content was seen in all tributaries, and cadmium concentration increased only in some watercourses. As for all other trace elements, no marked content increase was observed.

Iron and manganese release in coal mine drainage wetland microcosms

1995 ◽  
Vol 32 (3) ◽  
pp. 187-192 ◽  
Author(s):  
W. J. Tarutis ◽  
R. F. Unz
Keyword(s):  
Metal Oxides ◽  
Constructed Wetlands ◽  
Metal Ion ◽  
Manganese Oxides ◽  
Mine Drainage ◽  
Organic Substrate ◽  
Mushroom Compost ◽  
Reducing Conditions ◽  
Iron Manganese ◽  
Iron And Manganese

The primary mechanisms responsible for the removal and retention of iron, manganese, and sulfate in constructed wetlands receiving acidic mine drainage (AMD) include the formation of metal oxides and sulfides within the sediments. This study was initiated to determine the kinetics of metal ion liberation, under reducing conditions, from synthetic and naturally occurring iron and manganese oxides typically found in AMD precipitates. Rates of metal ion liberation were determined during time series incubations of an organic substrate (spent mushroom compost) to which five metal oxides of varying crystallinity (amorphous and crystalline oxides of iron and manganese; natural AMD oxide) were added. All experiments were carried out in silicone-sealed polycarbonate centrifuge tubes incubated at 22°C for a period of 3, 7, 10, 14, 21 or 28 days. Tubes were sacrificed after each incubation period and were analyzed for redox potential, pH, sulfide, and metals. All tubes exhibited reducing potentials within 3 days coupled with rapidly increasing concentrations of iron and manganese. Liberation of iron and manganese decreased with increasing mineral crystallinity (amorphous > natural AMD ≫ crystalline). The results suggest that metal ion liberation from oxide minerals may be an important source of iron and manganese within constructed wetlands receiving AMD.

scholarly journals ENRICHMENT FACTORS OF HEAVY METALS IN IRON - MANGANESE CONCRETIONS FROM IMPERFECTLY DRAINED SOILS

2018 ◽  
Vol 36 (1) ◽  
pp. 158 ◽  
Author(s):  
Δ. Γασπαράτος ◽  
Κ. Χαϊντούτη ◽  
Δ. Ταρενίδης ◽  
Α. Τσαγκαλίδης
Keyword(s):  
Heavy Metals ◽  
Manganese Oxides ◽  
Enrichment Factors ◽  
Soil System ◽  
Charged Surfaces ◽  
Lead And Cadmium ◽  
Reducing Conditions ◽  
Iron Manganese ◽  
Mn Oxides ◽  
Iron And Manganese

The Fe-Mn concretions are morphological features of soils under alternating oxidizing and reducing conditions. They have a high adsorption capacity for many inorganic pollutants, like heavy metals. This study determines the enrichment factors of Fe, Μη, Ni, Co, Pb and Cd in Fe-Mn concretions collected from imperfectly -drained soils in Central Greece. The data show that the concretions absorbed significant amounts of heavy metals and especially of lead and cadmium from the soil system. According to the enrichment factors, the affinity of heavy metals for the concretions due to the charged surfaces of iron and manganese oxides, follow the order Pb>Cd>Mn>Co>Ni>Fe. McKenzie (1980) also found adsorption of cobalt, manganese, nickel and lead at the same order on nine synthetic manganese oxides while Nimfopoulos et al. (1997) showed that the mobility of the metals at karst cavities enriched with Mn oxides followed the order Na>K>Mg>Sr>Mn>As>Zn>Ba>AI>Fe>Cu>Cd>Pb.

Ultrasound-Assisted Citric Acid Extraction of Zinc in Plateau Red Soil and Tessier Speciation Study

2013 ◽  
Vol 726-731 ◽  
pp. 4464-4467
Author(s):  
Wei Wei ◽  
Xue Jin Zhou ◽  
Yun Tao Gao
Keyword(s):  
Heavy Metal ◽  
Citric Acid ◽  
Manganese Oxides ◽  
Red Soil ◽  
Extraction Rate ◽  
Acid Extraction ◽  
Speciation Study ◽  
Ultrasonic Assisted ◽  
Ultrasound Assisted ◽  
Iron And Manganese

Taking plateau red soil as research object, using the ultrasonic-assisted organic acid extraction the heavy metal zinc in it, and analyze the form of zinc. Results showed that the extraction rate can reach 68%, with the increase of time, the extraction effect of zinc is obviously enhanced in this method. Ultrasonic-assisted citric acid extraction soil can increase the extraction rate of exchangeable, bound to carbonates and bound to iron and manganese oxides relatively.

The Enrichment Regularity of Rare Earth Elements and Resource Characteristics in Polymetallic Nodules/Crusts

2011 ◽  
Vol 284-286 ◽  
pp. 2497-2500
Author(s):  
Lian Feng Gao ◽  
Peng Zhang ◽  
Ying Zhang ◽  
Zhen Guo Zhang ◽  
Chang Shui Liu
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Manganese Oxides ◽  
Average Content ◽  
Cobalt Nickel ◽  
Mineral Development ◽  
Polymetallic Nodules ◽  
The Pacific ◽  
Resource Characteristics ◽  
Iron Manganese

Polymetallic nodules/crusts are one of the most important mineral deposits in the ocean, in which iron, manganese, copper, cobalt, nickel and other metals are rich, and rare earth elements are rich, too. In this study, the contents of 11 rare earth samples in polymetallic nodules/crusts from the Pacific, Atlantic, Indian Ocean and north of the South China Sea are analyzed. The average content of rare earth in polymetallic nodules/crusts is 1265.57×10-6, the average content of nodules is 1096.96×10-6, and the average content of crust is 1623.88×10-6. The enrichment of rare earth elements is controlled by iron and manganese oxides and clay minerals in nodules/crusts, which could absorb rare earth elements from seawater and sediment. Ce elements are highly enriched, making polymetallic nodules/crusts become the first used rare earth elements in mineral development.

Strategies for EELS Data Analysis. Introducing UMAP and HDBSCAN for Dimensionality Reduction and Clustering

2021 ◽  
pp. 1-14
Author(s):  
Javier Blanco-Portals ◽  
Francesca Peiró ◽  
Sònia Estradé
Keyword(s):  
Dimensionality Reduction ◽  
Clustering Analysis ◽  
Manganese Oxides ◽  
Spatial Clustering ◽  
State Of The Art ◽  
Core Loss ◽  
Nonnegative Matrix ◽  
Case Scenario ◽  
Electron Energy Loss ◽  
Iron And Manganese

Hierarchical density-based spatial clustering of applications with noise (HDBSCAN) and uniform manifold approximation and projection (UMAP), two new state-of-the-art algorithms for clustering analysis, and dimensionality reduction, respectively, are proposed for the segmentation of core-loss electron energy loss spectroscopy (EELS) spectrum images. The performances of UMAP and HDBSCAN are systematically compared to the other clustering analysis approaches used in EELS in the literature using a known synthetic dataset. Better results are found for these new approaches. Furthermore, UMAP and HDBSCAN are showcased in a real experimental dataset from a core–shell nanoparticle of iron and manganese oxides, as well as the triple combination nonnegative matrix factorization–UMAP–HDBSCAN. The results obtained indicate how the complementary use of different combinations may be beneficial in a real-case scenario to attain a complete picture, as different algorithms highlight different aspects of the dataset studied.

Enhancing Cd(II) Adsorption on Rice Straw Biochar by Modification of Iron and Manganese Oxides

2021 ◽  
Author(s):  
Wen-Tao TAN ◽  
Hang ZHOU ◽  
Shang-Feng TANG ◽  
Peng ZENG ◽  
Jiao-Feng GU ◽  
...  
Keyword(s):  
Rice Straw ◽  
Manganese Oxides ◽  
Rice Straw Biochar ◽  
Iron And Manganese
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