scholarly journals Formation of manganese phosphate and manganese carbonate during long-term sorption of Mn2+by viable Shewanella putrefaciens: effects of contact time and temperature

2015 ◽  
Vol 17 (4) ◽  
pp. 780-790 ◽  
Author(s):  
Natalia Chubar ◽  
Cristina Avramut ◽  
Tom Visser
Keyword(s):  
Contact Time ◽  
Shewanella Putrefaciens ◽  
Manganese Carbonate ◽  
Manganese Phosphate

Mn2+sorption by Mn-reducing bacteriumShewanella putrefaciensover 30 days.

scholarly journals The key role of contact time in elucidating the mechanisms of enhanced decontamination by Fe0/MnO2/sand systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Viet Cao ◽  
Ghinwa Alyoussef ◽  
Nadège Gatcha-Bandjun ◽  
Willis Gwenzi ◽  
Chicgoua Noubactep
Keyword(s):  
Contact Time ◽  
Diffusive Transport ◽  
Iron Hydroxides ◽  
Iron Corrosion ◽  
Short Term ◽  
Batch Studies ◽  
Water Decontamination ◽  
Co Precipitation

AbstractMetallic iron (Fe0) has shown outstanding performances for water decontamination and its efficiency has been improved by the presence of sand (Fe0/sand) and manganese oxide (Fe0/MnOx). In this study, a ternary Fe0/MnOx/sand system is characterized for its discoloration efficiency of methylene blue (MB) in quiescent batch studies for 7, 18, 25 and 47 days. The objective was to understand the fundamental mechanisms of water treatment in Fe0/H2O systems using MB as an operational tracer of reactivity. The premise was that, in the short term, both MnO2 and sand delay MB discoloration by avoiding the availability of free iron corrosion products (FeCPs). Results clearly demonstrate no monotonous increase in MB discoloration with increasing contact time. As a rule, the extent of MB discoloration is influenced by the diffusive transport of MB from the solution to the aggregates at the bottom of the vessels (test-tubes). The presence of MnOx and sand enabled the long-term generation of iron hydroxides for MB discoloration by adsorption and co-precipitation. Results clearly reveal the complexity of the Fe0/MnOx/sand system, while establishing that both MnOx and sand improve the efficiency of Fe0/H2O systems in the long-term. This study establishes the mechanisms of the promotion of water decontamination by amending Fe0-based systems with reactive MnOx.

Acid Fracture Conductivity Behavior of Tahe Carbonate: High Closure Stress, Long-Term Conductivity, and Composite Conductivity

2014 ◽  
Vol 1042 ◽  
pp. 44-51
Author(s):  
Jia Nye Mou ◽  
Mao Tang Yao ◽  
Ke Xiang Zheng
Keyword(s):  
Creep Deformation ◽  
Contact Time ◽  
Carbonate Reservoir ◽  
Fracture Conductivity ◽  
Acid Rock ◽  
Acid Fracturing ◽  
Closure Stress ◽  
Composite Conductivity ◽  
Conductivity Behavior

Acid fracture conductivity is a key parameter in acid fracturing designs and production performance prediction. It depends on the fracture surface etching pattern, rock mechanical properties, and closure stress. The fracture surfaces undergo creep deformation under closure stress during production. Preservation of fracture conductivity becomes a challenge at elevated closure stress. In this paper, we investigated acid fracture conductivity behavior of Tahe deep carbonate reservoir with high closure stress and high temperature. A series of acid fracture conductivity experiment was conducted in a laboratory facility designed to perform acid fracture conductivity. Gelled acid and cross linked acid with different acid-rock contact times were tested for analyzing the effect of acid type and acid-rock contact time on the resulting conductivity. Closure stress up to 100MPa was tested to verify the feasibility of acid fracturing for elevated closure stress. Long-term conductivity up to 7-day was tested to determine the capability of conductivity retaining after creep deformation. Composite conductivity of acid fracture with prop pant was also carried out. The study shows that the fracture retained enough conductivity even under effective closure stress of 70MPa. The gelled acid has a much higher conductivity than the cross linked acid for the same contact time. For the gelled acid, contact time above 60-minute does not lead to conductivity increase. Acid fracture with prop pant has a lower conductivity at low closure stress and a higher conductivity at high closure stress than the acid fracture, which shows composite conductivity is a feasible way to raise conductivity at high closure stress. The long-term conductivity tests show that the acid fracture conductivity decreases fast within the first 48-hour and then levels off. The conductivity keeps stable after 120-hour. An acid fracture conductivity correlation was also developed for this reservoir.

A novel nanoporous Fe-doped lithium manganese phosphate material with superior long-term cycling stability for lithium-ion batteries

Nanoscale ◽  
2015 ◽  
Vol 7 (27) ◽  
pp. 11509-11514 ◽  
Author(s):  
Pengjian Zuo ◽  
Liguang Wang ◽  
Wei Zhang ◽  
Geping Yin ◽  
Yulin Ma ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Lithium Ion ◽  
Cycling Stability ◽  
Manganese Phosphate ◽  
Phosphate Material ◽  
Lithium Manganese ◽  
Lithium Manganese Phosphate ◽  
Capacity Decay

LiMn0.8Fe0.2PO4 exhibits an ultralong cycling ability exceeding 1000 cycles with a capacity decay of 0.0068 mA h g−1 loss per cycle.

scholarly journals Synthesis of novel red phosphate pigments from manganese carbonate to imitate natrophilite

Cerâmica ◽  
2018 ◽  
Vol 64 (372) ◽  
pp. 623-626
Author(s):  
H. Onoda ◽  
S. Fujikado
Keyword(s):  
Color Space ◽  
Xrd Analysis ◽  
Manganese Carbonate ◽  
X Ray Diffraction ◽  
Manganese Phosphate ◽  
A Value ◽  
Higher Temperature ◽  
Phosphate Pigments ◽  
Xrd Patterns ◽  
Visible Reflectance

Abstract A novel red pigment, sodium manganese phosphate (NaMnPO4), imitating natrophilite, was synthesized from manganese carbonate by heating under various conditions. The powders obtained were investigated by X-ray diffraction (XRD) analysis, infrared spectroscopy, ultraviolet-visible reflectance spectroscopy, and L*a*b* color space. Samples synthesized at 500-800 °C presented XRD patterns associated with NaMnPO4. By heating at a higher temperature, the samples exhibited lighter color. The sample synthesized at 700 °C indicated the highest a* value. Furthermore, the effects of varying relative amounts of constituents were also studied. The temperature and period of heating, volume of water, and phosphate content affected the color phase of the pigments.

Sorption and precipitation of Mn2+ by viable and autoclaved Shewanella putrefaciens: Effect of contact time

2013 ◽  
Vol 100 ◽  
pp. 232-250 ◽  
Author(s):  
Natalia Chubar ◽  
Tom Visser ◽  
Cristina Avramut ◽  
Helen de Waard
Keyword(s):  
Contact Time ◽  
Shewanella Putrefaciens

Distribution of fractions of zinc and their contribution towards availability and plant uptake of zinc under long-term maize (Zea mays L.) - wheat (Triticum aestivum L.) cropping on an Inceptisol

Soil Research ◽  
2008 ◽  
Vol 46 (1) ◽  
pp. 83 ◽  
Author(s):  
Sanjib Kumar Behera ◽  
Dhyan Singh ◽  
B. S. Dwivedi ◽  
Sarjeet Singh ◽  
K. Kumar ◽  
...  
Keyword(s):  
Agricultural Research ◽  
Soil Depth ◽  
Indian Agricultural Research Institute ◽  
Triticum Aestivum L ◽  
Average Concentration ◽  
Wheat Crop ◽  
Manganese Carbonate ◽  
Intensive Farming ◽  
Zn Uptake

Intensive farming with high yielding cultivars, application of high analysis NPK fertilisers, and reduced use of organic manures caused a decrease in the availability of zinc (Zn) in Indian soils. We collected soil and plant samples from an ongoing long-term experiment at Indian Agricultural Research Institute, New Delhi, to study the distribution of different fractions of Zn in an Inceptisol and their contribution towards the Zn availability in soil and Zn uptake in maize–wheat crop rotation. The treatments used for the study were NPK, NPK + FYM, NPK + Zn, and control (no fertiliser or manure). The DTPA-Zn concentration in soil was higher where Zn had been applied and declined with an increase in soil depth. The distribution of different fractions of Zn under various treatments and depths was inconsistent, and varied in a cropping year. The average concentration of total Zn (mg/kg) was 183, 183, 171, and 211 in 0–0.15, 0.15–0.30, 0.30–0.45, and 0.45–0.60 m depth, respectively. Residual Zn was the dominant portion of total Zn at all soil depths. Grain and stover yield of maize ranged from 1.10 to 2.43 t/ha and 1.22 to 2.46 t/ha, respectively, under different treatments, whereas, the yield of wheat grain varied from 2.25 to 4.69 t/ha and that of wheat straw from 2.56 to 5.20 t/ha. Highest uptake of Zn by both the crops occurred in Zn-treated plots. Zinc associated with easily reducible manganese, carbonate and iron and aluminum oxides contributed directly towards DTPA-extractable Zn. Sorbed Zn (SORB-Zn) and Zn associated with organic matter (OM-Zn) contributed significantly towards Zn uptake by the 2 crops.

Study on control of micro-pollutants by BAC filtration

2008 ◽  
Vol 58 (3) ◽  
pp. 677-682 ◽  
Author(s):  
Z. H. Zhang ◽  
L. Shao
Keyword(s):  
Contact Time ◽  
Continuous Operation ◽  
The Other ◽  
Formation Potential ◽  
Term Operation ◽  
Correlative Analysis ◽  
Trihalomethane Formation Potential ◽  
One Year ◽  
Micro Pollutants

The objective of this research was to evaluate removal efficiency of micro-pollutants in a BAC filter that followed ozonation for long term operation. The experimental results showed that after continuous operation for one year BAC filter still maintained a removal of 15 ∼ 20% for CODMn and 20 ∼ 30% of removal for UV254. Correlative analysis based on lots of data found that empty bed contact time (EBCT) instead of flow rate could obviously impact on removal effect of micro-pollutants in BAC filter. And the optimal relationship between EBCT and removal effect of micro-pollutants for BAC filter was logarithm. On the other hand, long term running of BAC filter proved that there was a good removal of chloroform formation potential, but the removal of brominated trihalomethane formation potential decline with further bromization, even there appeared to be formation of bromoform in BAC filter.

Effects of aging on the bioavailability and sorption/desorption behavior of biphenyl in soils

2005 ◽  
Vol 52 (8) ◽  
pp. 95-105 ◽  
Author(s):  
J.-H. Park ◽  
M. Sharer ◽  
Y. Feng ◽  
S.-Y. Chung ◽  
T.C. Voice ◽  
...  
Keyword(s):  
Aging Time ◽  
Contact Time ◽  
Sorption Isotherms ◽  
Soil Types ◽  
Desorption Kinetic ◽  
Mineralization Kinetics ◽  
Effects Of Aging ◽  
Kinetics Of ◽  
Uptake And Release

The effects of aging (soil-chemical contact time) on bioavailability, one of the main variables for determining the persistence of organic chemicals in the environment, is poorly understood. There are few studies that have tested the effects of long-term aging on chemical dynamics in soils and have related these effects to bioavailability tests of these aged compounds. In this study, sorption/desorption behavior of biphenyl (BP) on two soil types (Capac A and Capac B) was evaluated for aging times of 24 hours and 8 months. Then bioavailability experiments of BP on the same soils were performed after aging times of 24 hours to 6 months. Sorption isotherms and desorption kinetic profiles were prepared to analyze changes in uptake and release, respectively, due to aging of BP. Mineralization kinetics of BP to 14CO2 by a strain of Pseudomonas putida was used to assess changes in bioavailability due to aging. Data indicates that there was an increase in sorption with aging time for BP on both soil types. The rate of BP desorption did not much change with increased aging time. The extent of BP mineralization was found to decrease with aging time.

scholarly journals Nanosized Zincated Hydroxyapatite as a Promising Heterogeneous Photo-Fenton-Like Catalyst for Methylene Blue Degradation

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Van Dat Doan ◽  
Van Thuan Le ◽  
Thi Thanh Nhi Le ◽  
Hoai Thuong Nguyen
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Contact Time ◽  
Degradation Mechanism ◽  
X Ray Diffraction ◽  
Methylene Blue Degradation ◽  
X Ray ◽  
Transmission Electron ◽  
Substitution Degree

This study is devoted to synthesis of nanosized zincated hydroxyapatite (Zn-HA) and its utilization as a heterogeneous photo-Fenton-like catalyst for degradation of methylene blue (MB) in aqueous solution. The prepared catalyst was characterized by various techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray, and Fourier transform infrared spectroscopy. The catalytic activity of Zn-HA towards MB and the effects of various experimental factors such as pH, zinc substitution degrees, initial MB concentration, and H2O2 dosage were studied in detail. The results showed that the zinc substitution degree of 0.4 is optimal to get the highest degradation efficiency under conditions of pH = 10, H2O2 dosage of 0.05 M, and MB concentration of 30 mg/L for a contact time of 120 min. The degradation mechanism was proposed and discussed thoroughly. Besides, the ability of long-term use for the synthesized catalyst was also evaluated.

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