scholarly journals Effect of Modified Kiln Dust and a Cationic Surfactant on the Removal of Aromatic and Heavy Metal Compounds from Fuels

2019 ◽  
Vol 35 (5) ◽  
pp. 1508-1513
Author(s):  
Noura Yahya El Mehbad
Keyword(s):  
Heavy Metals ◽  
Cationic Surfactant ◽  
Oil Quality ◽  
Cement Kiln ◽  
Polar Molecules ◽  
Optimum Conditions ◽  
Metal Compounds ◽  
Before And After ◽  
The Stability ◽  
Kiln Dust

This paper aims to investigate removal of aromatic and heavy metals compounds from fuels using cement kiln dust, and a cationic surfactant. The effect of a cationic surfactant and the composition of kiln dust on the stability of fuel was studied. The optimum conditions of adsorption were investigated. The stability of fuels was improved after adsorption because of the absorption of heavy metals, which act as catalysts. The concentrations of kiln dust and additives are effective for the absorption of heteroatoms of polar and nonpolar molecules. The addition of different concentrations of the cationic surfactant to kiln dust enhances the removal of polar molecules in fuel. The relation between the efficiency of the cationic surfactant and the enhanced removal of polar molecules was established. This study suggests a new mechanism to remove polar molecules according to the structure of the additive. Several parameters that affect the performance of the removal process were investigated under all optimum conditions. A complete chemical analysis of the fuels before and after treatment was performed, and the stability of the fuel was evaluated at different conditions. The prepared additive could enhance the oil quality and is environmentally safe. The adsorption behaviour of kiln dust was investigated to find a new mechanism of its efficiency. The results confirm the role of the cationic surfactant in the purification of fuels and the effectiveness of kiln dust in improving the stability of fuels, which depend on the concentration of the cationic surfactant and the nature of the kiln dust.

scholarly journals Uptake of Cationic Dyes by Cement Kiln Dust: Sorption Mechanism and Equilibrium Isotherm

2002 ◽  
Vol 20 (7) ◽  
pp. 657-668 ◽  
Author(s):  
Mamdouh M. Nassar ◽  
Abd. El Hakim A. Daifullah ◽  
Yehia H. Magdy ◽  
Ebrahiem E. Ebrahiem
Keyword(s):  
Sodium Silicate ◽  
Active Sites ◽  
Freundlich Isotherm ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
X Ray Diffraction ◽  
Exchange Reactions ◽  
Sorptive Capacity ◽  
Before And After ◽  
Kiln Dust

The mechanistic aspects of the sorption of Basic Blue-3 and Basic Red-22 on to cement kiln dust (CKD) have been investigated. The by-pass kiln dust before and after washing with water was characterized by X-ray diffraction methods, IR spectroscopy and elemental analysis. Two forms of by-pass kiln dust were used in this study without any treatment, i.e. in powder and pelletized form (the latter being achieved using water or sodium silicate). Equilibrium isotherms to assess the maximum capacity of the two basic dyes on the two forms of CKD were evaluated using a computer program. This allowed two-, three- and four-parameter adsorption models to be studied; it was found that the piecewise Freundlich isotherm yielded an excellent overall fit. Washing with water led to the loss of some active sites responsible for the sorptive capacity. The increase in capacity observed after pelletization with water rather than with sodium silicate could be explained by an increase in hydroxy moieties that undergo exchange reactions. In both cases of pelletization, the adsorption capacity was less than for the unwashed powdered form. The uptake order was found to be: unwashed powder > pellets with water > pellets with sodium silicate.

Equilibrium analysis for heavy metal cation removal using cement kiln dust

2014 ◽  
Vol 70 (6) ◽  
pp. 1011-1018 ◽  
Author(s):  
Mohamed El Zayat ◽  
Sherien Elagroudy ◽  
Salah El Haggar
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Removal ◽  
Equilibrium Constants ◽  
Surface Complexation ◽  
Chemical Precipitation ◽  
Equilibrium Analysis ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Kiln Dust

Ion exchange, reverse osmosis, and chemical precipitation have been investigated extensively for heavy metal uptake. However, they are deemed too expensive to meet stringent effluent characteristics. In this study, cement kiln dust (CKD) was examined for the removal of target heavy metals. Adsorption studies in completely mixed batch reactors were used to generate equilibrium pH adsorption edges. Studies showed the ability of CKD to remove the target heavy metals in a pH range below that of precipitation after an equilibrium reaction time of 24 h. A surface titration experiment indicated negative surface charge of the CKD at pH below 10, meaning that electrostatic attraction of the divalent metals can occur below the pH required for precipitation. However, surface complexation was also important due to the substantive metal removal. Accordingly, a surface complexation model approach that utilizes an electrostatic term in the double-layer description was used to estimate equilibrium constants for the protolysis interactions of the CKD surface as well as equilibria between background ions and the sorbent surface. It was concluded that the removal strength of adsorption is in the order: Pb > Cu > Cd. The experiments were also supported by Fourier transform infrared spectroscopy (FTIR).

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

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