scholarly journals Polyethylenimine-functionalized cellulose aerogel beads for efficient dynamic removal of chromium(vi) from aqueous solution

RSC Advances ◽  
2017 ◽  
Vol 7 (85) ◽  
pp. 54039-54052 ◽  
Author(s):  
Dong-Mei Guo ◽  
Qing-Da An ◽  
Zuo-Yi Xiao ◽  
Shang-Ru Zhai ◽  
Zhan Shi
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Cross Linking ◽  
Amino Groups ◽  
Chromium Vi ◽  
Cellulose Aerogel

Cellulose aerogel beads with high a density of reactive amino groups were facilely prepared via a cross-linking reaction for efficient dynamic removal of Cr(vi) from aqueous solutions.

Studies on the Treatment of Wastewaters Containing Cr6+ with Iron Oxide-Silica Composite Materials Prepared by Different Methods

2014 ◽  
Vol 353 ◽  
pp. 33-38
Author(s):  
Rafique Ullah ◽  
Biplob Kumer Deb ◽  
Mohammad Yousuf Ali Mollah
Keyword(s):  
Aqueous Solution ◽  
Iron Oxide ◽  
Adsorption Isotherm ◽  
Aqueous Solutions ◽  
Order Kinetic ◽  
Efficient Technology ◽  
Experimental Conditions ◽  
Initial Concentration ◽  
Oxide Composite ◽  
Chromium Vi

Chromium (VI) is known to be carcinogenic to humans and thus it is important to ensure the removal of Chromium (VI) from aqueous solutions and industrial effluents. The present study introduces a good alternative method for Cr (VI) removal from aqueous solutions at ambient temperature by adsorption, allowing the development of newer, lower operational cost, and more efficient technology than other processes already in use. Adsorption was found to be dependent on pH and initial concentration of Cr (VI) solution. Results of adsorption studies suggest that pristine iron oxide and silicon (IV) oxide removes 72.10% and 24.73%, respectively. The iron oxide – silicon (IV) oxide composite, prepared in this work, removes 93.88% Cr (VI) in 20 minutes from aqueous solution at an initial concentration of 50 mgL-1at pH 4.8 ± 0.2. The effect of concentration, contact time, adsorbent dose and solution pH on the adsorption of Cr (VI) were studied in detail in batch experiments. Studies of the sorption kinetics shows that equilibrium adsorption was attained in 20 minutes depending on other experimental conditions. The kinetic data justified Lagergren’s first-order kinetic equation. Adsorption isotherm study showed that the results fulfilled the Langmuir Model of adsorption isotherm. The maximum adsorption (98.28%) was recorded at pH 3 in 90 minutes for the initial Cr (VI) concentration of 50 mg L-1. Therefore, it can be concluded that iron oxide – silicon (IV) oxide composite is a potential adsorbent for adsorption of Cr (VI) from aqueous solution.

scholarly journals Removal of Chromium(VI) from Aqueous Solutions Using Fe3O4 Magnetic Polymer Microspheres Functionalized with Amino Groups

Materials ◽  
2015 ◽  
Vol 8 (12) ◽  
pp. 8378-8391 ◽  
Author(s):  
Kai Wang ◽  
Guangming Qiu ◽  
Hongyu Cao ◽  
Ruifa Jin
Keyword(s):  
Aqueous Solutions ◽  
Polymer Microspheres ◽  
Amino Groups ◽  
Chromium Vi

Reduction remediation of hexavalent chromium by bacterial flora in Cr(VI) aqueous solution

2010 ◽  
Vol 61 (11) ◽  
pp. 2889-2896 ◽  
Author(s):  
Qian Wang ◽  
Xinhua Xu ◽  
Fanglin Zhao ◽  
Zhihao Liu ◽  
Jinan Xu
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Low Cost ◽  
Bacterial Flora ◽  
Industrial Water ◽  
Indigenous Bacteria ◽  
Anaerobic Reactor ◽  
Priority Pollutant ◽  
Chromium Vi ◽  
Energy Conserving

Chromium(VI) is a priority pollutant in soils and wastewaters and reduction of Cr(VI) to Cr(III) is a solution to this problem. In this study a low-cost method was proposed to adapt indigenous bacteria and use them to reduce Cr(VI) in solutions. The experiment results show that Cr(VI) could be efficiently reduced by indigenous bacteria under anaerobic and pH-unadjusted conditions. After about 24 h the concentration of Cr(VI) could be reduced from 21.74 mg/L to below 0.5 mg/L. The observed Cr(VI) reduction rates were affected by temperature and pH. Cr(VI) in aqueous solutions could be reduced to Cr(III) completely and partly be incepted by the organisms. Cr(VI) reduction was enzyme-mediated. It was not an energy-conserving process but a detoxification reaction. This method could be used in an anaerobic reactor to treat low-concentration wastewater or industrial water as the last step.

Breakthrough analysis for hexavalent chromium removal from drinking water in a fixed bed column

2009 ◽  
Vol 9 (6) ◽  
pp. 661-670 ◽  
Author(s):  
S. P. Dubey ◽  
K. Gopal
Keyword(s):  
Aqueous Solution ◽  
Hexavalent Chromium ◽  
Fixed Bed ◽  
Entropy Change ◽  
Spectroscopic Technique ◽  
Fixed Bed Column ◽  
Chromium Vi ◽  
Fixed Bed Adsorption ◽  
Optimal Column ◽  
Eucalyptus Bark

The activated carbon of Eucalyptus globulus was tested for their effectiveness in removing hexavalent chromium from aqueous solution using column experiments. Result revealed that adsorption of chromium(VI) on eucalyptus bark carbon was endothermic in nature. Thermodynamic parameters such as the entropy change, enthalpy change and Gibbs free energy change were found to be 1.39 kJ mol−1 K−1, 1.08 kJ mol−1 and −3.85 kJ mol−1, respectively. Different chromium concentrations were used for the fixed bed adsorption studies. The pre- and post-treated adsorbents were characterized using a FTIR spectroscopic technique. It was concluded that Eucalyptus bark carbon column could be used effectively for removal of hexavalent chromium from aqueous solution at optimal column conditions. This study showed that this biological material is potential adsorbent of Cr(VI) from water.

Effect of thermal history of aqueous solutions of KCl on the metastable zone width

1984 ◽  
Vol 49 (3) ◽  
pp. 559-569 ◽  
Author(s):  
Jaroslav Nývlt
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Thermal History ◽  
Equilibrium Solubility ◽  
Metastable Zone Width ◽  
Zone Width ◽  
Preceding Experiment ◽  
History Of ◽  
Metastable Zone ◽  
The Given

The metastable zone width of an aqueous solution of KCI was measured as a function of the time and temperature of overheating above the equilibrium solubility temperature. It has been found that when the experiments follow close upon one another, the parameters of the preceding experiment affect the results of the experiment to follow.The results are interpreted in terms of hypotheses advanced in the literature to account for the effect of thermal history of solution. The plausibility and applicability of these hypotheses are assessed for the given cause of aqueous solution of a well soluble electrolyte.

scholarly journals I. Thermo-electric behaviour of aqueous solutions with mercurial electrodes

1879 ◽  
Vol 29 (196-199) ◽  
pp. 472-482 ◽  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Internal Diameter ◽  
Thermo Electric ◽  
Thin Glass ◽  
Mercury Surface

In order to investigate this subject, I devised and constructed the following apparatus :—A and B are two thin glass basins, 81 millims. internal diameter (= 5,153 sq. millims. of mercury surface), and 6·0 centims. deep; each containing a layer of mercury about 1·0 centim. deep, covered by a layer, about 3 centims. deep, of the aqueous solution to be examined.

scholarly journals Meta-studtite stability in aqueous solutions. Impact of HCO3−, H2O2 and ionizing radiation on dissolution and speciation

2021 ◽  
Author(s):  
Junyi Li ◽  
Zoltán Szabó ◽  
Mats Jonsson
Keyword(s):  
Aqueous Solution ◽  
Ionizing Radiation ◽  
Aqueous Solutions ◽  
Carbonate Complexes ◽  
C Nmr

Four different uranyl-(peroxide)-carbonate complexes were identified during studtite and meta-studtite dissolution in aqueous solution containing 10 mM HCO3− by 13C NMR.

scholarly journals Visualization of microwave near-field distribution in sodium chloride and glucose aqueous solutions by a thermo-elastic optical indicator microscope

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhirayr Baghdasaryan ◽  
Arsen Babajanyan ◽  
Levon Odabashyan ◽  
Jung-Ha Lee ◽  
Barry Friedman ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Field Distribution ◽  
Near Field ◽  
Absorption Properties ◽  
Novel Approach ◽  
Concentration Changes ◽  
Biological Liquids ◽  
Optical Indicator ◽  
Distribution Intensity

AbstractIn this study, a new optical method is presented to determine the concentrations of NaCl and glucose aqueous solutions by using a thermo-elastic optical indicator microscope. By measuring the microwave near-field distribution intensity, concentration changes of NaCl and glucose aqueous solutions were detected in the 0–100 mg/ml range, when exposed to microwave irradiation at 12 GHz frequency. Microwave near-field distribution intensity decreased as the NaCl or glucose concentration increased due to the changes of the absorption properties of aqueous solution. This method provides a novel approach for monitoring NaCl and glucose in biological liquids by using a CCD sensor capable of visualizing NaCl and glucose concentrations without scanning.

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