Separation Technology,
M. Jadidi; N. Etesami; M. Nasr Esfahany
Volume 14, Issue 3 , August 2017, , Pages 31-40
Abstract
In this study adsorption of Cr(VI) from aqueous solution by Fe3O4 nanoparticles was investigated. Desorption process and recovery of nanoparticles using different solutions were then carried out, and it was observed that NaOH (0.5M) can remove 90% of adsorbed chromium ions. Following the completion of ...
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In this study adsorption of Cr(VI) from aqueous solution by Fe3O4 nanoparticles was investigated. Desorption process and recovery of nanoparticles using different solutions were then carried out, and it was observed that NaOH (0.5M) can remove 90% of adsorbed chromium ions. Following the completion of adsorption/ desorption cycles, it was determined that nanoparticles have still had a high ability of chromium ions adsorption after 4 cycles. In addition, it was found that when iron oxide nanoparticles were washed with NaOH solution, the adsorption efficiency increases in the next cycle. FTIR spectra and zeta potential analysis, demonstrated the increased in surface positively charged of nanoparticles leads to increased electrostatic attraction forces between the iron oxide nanoparticles and chromium ions which finally resulted in adsorption increasing. So in this research, pretreatment of nanoparticles with NaOH solution modifies the surface of Fe3O4 nanoparticles by increasing surface positively charged mechanism and the adsorption efficiency has improved in the next cycle.
Separation Technology,
Sh. Houshyar; M. Torab-Mostaedi; S. M. A. Moosavian; Seyed Hamed Mousavi; M. Asadollahzadeh
Volume 14, Issue 3 , August 2017, , Pages 82-95
Abstract
The droplet size distribution in the column is usually represented as the average volume to surface area, known as the Sauter mean drop diameter. It is a key variable in the extraction column design. A study of the drop size distribution and Sauter-mean drop diameter for a liquid-liquid extraction column ...
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The droplet size distribution in the column is usually represented as the average volume to surface area, known as the Sauter mean drop diameter. It is a key variable in the extraction column design. A study of the drop size distribution and Sauter-mean drop diameter for a liquid-liquid extraction column has been presented for a range of operating conditions and three different liquid-liquid systems. The effects of rotor speed, and dispersed and continuous phase velocities on drop size are investigated. Drop size distribution are appropriately described using the normal and log-normal probability density functions. The mathematical approach is used to determine the constant parameters in these functions and to provide the fit of the experimental data with them. and empirical expressions are derived to predict the parameters of the distribution curve as a function of operating variables, and physical properties of the systems. Good agreement between the prediction and experiments was achieved for all investigated operating conditions. An empirical correlation is also proposed to predict the Sauter-mean drop diameter with mean deviation of 9.8%.