Drop behaviour characteristics in different operating regimes in an L-shaped pulsed sieve-plate column

In this study, the influence of different operating regimes on drop behaviour in an L‐shaped pulsed sieve‐plate column has been investigated and the effects of pulsation intensity and phase superficial velocities on drop diameters are evaluated. The toluene‐water system with 0.03 L/L (3 vol%) acetone as a mass transfer agent is used. Experimental observations reveal that with increasing pulsation intensity, drop sizes slightly decrease and by reaching to the end of mixer‐settler regime, they significantly decrease followed by a mild decrease in the dispersion regime. Moreover, it is observed that mean drop size firstly varies inversely as both phase superficial velocities change, while it slightly increases with further increase in superficial velocities. Finally, some of the most recommended correlations are compared to the experimental data. It is revealed that these correlations show the highest deviation in the lower end of the mixer‐settler regime (> 40 %), while in the dispersion regime it become

Investigation of the Effect of Nanoparticles in the Cephalexin adsorption onto Walnut Shell-based Activated Carbon

Background and purpose: Recently, release of pollutants such as pharmaceuticals to the environment becomes one of the most important problems for soil and water. The present study was conducted to introduce walnut shell-based activated carbon (AC) as a new low-cost adsorbent for the removal of cephalexin (CFX) antibiotic from aqueous solutions. Materials and Methods: This study was conducted in laboratory scale. To investigation of the morphology of the prepared walnut shell AC and nanoparticles, scanning electron microscopy analysis was applied. The effect of the presence of Fe2O3 and SiO2 nanoparticles on the adsorption of CFX on the walnut shell AC is also studied. Results: The maximum removal efficiency (RE) was obtained 98.4% at 100 mg/L initial CFX concentration and decreased to 72.9% with increasing in the initial CFX concentration to 200 mg/L. The results showed that the presence of nanoparticles in the optimum increased the RE of CFX by about 2.1 and 6.5% for Fe2O3 and SiO2 nanoparticles, respectively. Conclusion: Results suggest the potential of using the walnut shell AC as an adsorbent for effective treatment of pharmaceutical-contaminated wastewaters

Experimental investigation on the mean drop size and drop size distribution in an L-shaped pulsed sieve-plate column

Vertical pulsed extraction columns cannot be employed in applications with height limitations. On the other hand, the horizontal extraction columns have low throughput, which affects their applicability in industrial applications. Therefore, there is a need to design a new type of extractors for such circumstances. In this paper, an experimental study on drop sizes has been implemented in a novel L-shaped pulsed sieve-plate extraction column in the absence and presence of mass transfer. Moreover, new correlations are developed for prediction of the mean drop size and size distribution using the log-normal probability density function