scholarly journals A study of the microstructure of a bio-ash stabilized sandy clay soil

Author(s):  
Apampa O Ahmed ◽  
Oseni Kehinde ◽  
Popoola Monsuru

This research work studies the microstructure of a sandy-clay soil as it is stabilized with corn cob ash (CCA) in dosage rates of 0-3%, in steps of 0.5%, and comparing with OPC-CCA blends (2:1) and OPC alone. The aim being to study the progressive flocculation and agglomeration of the molecules of the soil, upon the addition of varying blends of CCA- OPC in small doses. The samples were taken for microstructural examination using the scanning electron microscope (SEM), and for elemental composition using the Energy Dispersive X-ray Spectroscope (EDS). Corresponding samples of the stabilized soil were subjected to the unconfined compressive strength (UCS) tests. The cat-ion exchange capacity of the soil was also computed. The SEM images indicate that for the CCA stabilized soil, the lattice structure of soil molecules is most clearly defined at 1% CCA content. This is comparable to the cat-ion exchange capacity of the soil (1.17%), and also corresponds to the point of maximum UCS (313.7KN/m2). Significantly, the UCS value returned for CCA stabilized soil was higher than that for OPC alone and for the OPC-CCA blend, within the test range of this study. The paper concludes that a significant level of stabilization could be attained with this soil type, with small doses of CCA, without the need for OPC, whose effect is more pronounced at higher doses and at the pozzolanic phase.

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.


2012 ◽  
Vol 511 ◽  
pp. 105-108
Author(s):  
Jin He Jiang

Mg1.5Mn0.5Ti0.75O4 was prepared by a coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material was investigation by X-ray, saturation capacity of exchange, and Kd measurement. The acid treatments of Mg1.5Mn0.5Ti0.75O4 caused Mg2+ extractions of more than 72%, while the dissolutions of Mn4+ and Ti4+ were less than 8.2%. The results showed that the Li+ extraction/insertion be progressed mainly by an ion-exchange mechanism. The acid treated samples had an ion exchange capacity of 10.6mmol/g for Li+.


Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 914 ◽  
Author(s):  
Lucia Mazzapioda ◽  
Stefania Panero ◽  
Maria Assunta Navarra

Nafion composite membranes, containing different amounts of mesoporous sulfated titanium oxide (TiO2-SO4) were prepared by solvent-casting and tested in proton exchange membrane fuel cells (PEMFCs), operating at very low humidification levels. The TiO2-SO4 additive was originally synthesized by a sol-gel method and characterized through x-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and ion exchange capacity (IEC). Peculiar properties of the composite membranes, such as the thermal transitions and ion exchange capacity, were investigated and here discussed. When used as an electrolyte in the fuel cell, the composite membrane guaranteed an improvement with respect to bare Nafion systems at 30% relative humidity and 110 °C, exhibiting higher power and current densities.


2005 ◽  
Vol 51 (11) ◽  
pp. 63-70 ◽  
Author(s):  
H. Inan ◽  
B. Beler Baykal

Ammonium selective natural zeolite clinoptilolite is suggested as a possible support material for nitrifying biofilms to help improve effluent ammonium quality through its high capacity of ammonium removal in the process of ion exchange. This will especially be helpful in cases where the biofilter receives peak or variable loads routinely or occasionally. At the time of peak loads or shocks of ammonium, ion exchange capacity will provide a buffer for the effluent ammonium quality. Data to support this suggestion is presented.


1997 ◽  
Vol 35 (7) ◽  
pp. 89-95 ◽  
Author(s):  
Aloysius U. Baes ◽  
Tetsuji Okuda ◽  
Wataru Nishijima ◽  
Eiji Shoto ◽  
Mitsumasa Okada

The adsorption of nitrate, chromium (VI), arsenic (V) and selenium (VI) anions in an amine modified coconut coir (MCC-AE : with secondary and tertiary amine functionality) were studied to determine the capability of this easily prepared and low-cost material in removing typical groundwater anion contaminants. Batch adsorption-ion exchange experiments were conducted using 200 mg MCC-AE, initially containing chloride as the resident anion, and 50 ml of different anion-containing water of varying concentrations. It is presumed, at this low pH, that only SeO42− remained as a divalent anion, while monovalent species H2AsO4− and HCrO4− predominated in their respective exchanging ion solutions. The adsorption data were fitted using the Freundlich equation and maximum adsorption for each anion was estimated using their respective Freundlich equation constants. MCC-AE exhibited preference for divalent Cr (VI) and Se (VI) anions compared with the Cl− resident ion. Maximum As (V) adsorption was 0.086 mmol/g, while maximum adsorption of Cr (VI), NO3− and Se (VI) anions was 0.327 mmol/g, 0.459 mmol/g, and 0.222 mmol/g, respectively. The ion exchange capacity of MCC-AE is estimated, based on its exchange capacity for nitrate, to be within 0.46 mmol of positive charges per gram. Similar adsorption experiments were conducted for comparison using commercial chloride-form Amberlite IRA-900 strong base (quaternary amine functionality) anion exchanger, with an exchange capacity of 4.2 meq/g. Maximum adsorption of the different ions in IRA-900 was about 3 times higher for NO3−, 9 times higher for Se (VI), 10 times higher for As (V) and 9 times higher for Cr (VI), than that in MCC-AE. Differences in the ion exchange behavior of MCC-AE and IRA-900 were probably due to the different amine functionalities in the two exchangers. The results suggest that MCC-AE may be used as a low-cost alternative adsorbent/ion exchanger for treatment of anion contaminants in groundwater.


2014 ◽  
Vol 96 ◽  
pp. 75-80 ◽  
Author(s):  
P.S Remya Devi ◽  
Himal Bhatt ◽  
M.N. Deo ◽  
Rakesh Verma ◽  
A.V.R. Reddy

2018 ◽  
Vol 29 (11) ◽  
pp. 2759-2765 ◽  
Author(s):  
Thiago R. Theodoro ◽  
Joslaine R. Dias ◽  
Júlia L. Penariol ◽  
Juliana O.V. Moura ◽  
Leandro G. Aguiar

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