Study of packed sieve tray column in ethanol purification using distillation process

Sieve tray becomes a popular contacting device in distillation process because of its relative simplicity and low cost. There is one way to improve the contact performance, especially mass transfer by modifying the sieve tray into packed sieve tray. This study was aimed to investigate the effect of adding packing in each tray to ethanol content on ethanol purification. This research was conducted via experiment and simulation approaches. The experiment used packed sieve tray that contained 3 cm and 5 cm bed of steel wool with 16 trays in the column, with operating pressure about 760 mmHg and performed in batch condition. The simulation used a reduced rated base model with some modifications for operation in the packed sieve tray column. It was found that the use of packed sieve tray gave better distillate in the batch distillation process than the use of sieve tray. The packed sieve tray raised distillate content about 8.89% when using 3 cm of packing and 23.31% when using 5 cm of packing when it was compared with sieve tray. The use of packed sieve tray could increase the mass transfer and reduce bubble diameter in the batch distillation process.

Bentonite and montmorillonite nanoparticles effectiveness in removal of fluoride from water solutions

The aim of this study was to evaluate the effectiveness of montmorillonite and bentonite nanoparticles in removal of fluoride from water solutions. This experimental study has been conducted in batch condition in which the effects of different parameters such as contact time, pH, initial concentration of fluoride and amount of adsorbent mass have been investigated. Finally thermodynamics, isotherm and kinetics of the both adsorbents have been studied. The maximum adsorption capacity for both adsorbents occurred at fluoride concentration of 20 mg/L, contact times of 60 minutes, pH = 3 and adsorbent mass of 0.25 g/L. The adsorption process was exothermic and the result of the Langmuir and Freundlich isotherm study show that bentonite nanoparticles behave more similar to the Langmuir isotherm model and montmorillonite nanoparticles behave according to the both isotherms. Furthermore, the adsorption of fluoride by bentonite in all studied fluoride concentrations and montmorillonite in higher fluoride concentrations followed pseudo second-order kinetics.

Intensifying the Fermentation of Aspergillus oryzae in a Stirred Bioreactor Using Maxblend Impeller

Background: The intensification of fermentation in stirred bioreactors is an attractive approach for commercial interests and industries that work with biochemical products. Alpha amylase is an enzymatic bio-products that is produced largely from Aspergillus oryzae. Using adaptable agitator can be an efficient way for stirred fermentation. Objective: This study, concentrated on enhancing the mixing process in order to intensify Aspergillus oryzae fermentation. A straight type of Maxblend® impeller was used as an agitator to investigate the incubation parameters compared with the use of a 6-blade double Rushton turbine. Method: Stirred fermentation was done in batch condition. Effect of flow pattern of mixing on fermentation parameters was investigated after each sampling. Results: The results showed that the Maxblend® significantly intensified both enzyme activity and growth rate at low and moderate rates of power consumption (P). The main reason for the decreases in the growth rate and the enzyme activity during agitation by the Rushton turbine at low and high Pv was the lack of oxygen and mycelial damage, respectively. Additionally, use of the Maxblend® significantly intensified the KLa at low and moderate rates of power consumption. Conclusion: Axial and uniform mixing by Maxblend® impeller was resulted in improving the fermentation characteristics and enzyme activity.

Synthesis of walnut shell modified with titanium dioxide and zinc oxide nanoparticles for efficient removal of humic acid from aqueous solutions

The main aim of this research was to study the efficiency of modified walnut shell with titanium dioxide (TiO2) and zinc oxide (ZnO) in the adsorption of humic acid from aqueous solutions. This experimental study was carried out in a batch condition to determine the effects of factors such as contact time, pH, humic acid concentration, dose of adsorbents (raw walnut shell, modified walnut shell with TiO2 and ZnO) on the removal efficiency of humic acid. pHzpc of raw walnut shell, walnut shell modified with TiO2 and walnut shell modified with ZnO were 7.6, 7.5, and 8, respectively. The maximum adsorption capacity of humic acid at concentration of 30 mg/L, contact time of 30 min at pH = 3 in an adsorbent dose of 0.02 g of walnut shell and ZnO and TiO2 modified walnut shell were found to be 35.2, 37.9, and 40.2 mg/g, respectively. The results showed that the studied adsorbents tended to fit with the Langmuir model. Walnut shell, due to its availability, cost-effectiveness, and also its high adsorption efficiency, can be proposed as a promising natural adsorbent in the removal of humic acid from aqueous solutions.

Chemodynamics of Methyl Parathion and Ethyl Parathion: Adsorption Models for Sustainable Agriculture

The toxicity of organophosphate insecticides for nontarget organism has been the subject of extensive research for sustainable agriculture. Pakistan has banned the use of methyl/ethyl parathions, but they are still illegally used. The present study is an attempt to estimate the residual concentration and to suggest remedial solution of adsorption by different types of soils collected and characterized for physicochemical parameters. Sorption of pesticides in soil or other porous media is an important process regulating pesticide transport and degradation. The percentage removal of methyl parathion and ethyl parathion was determined through UV-Visible spectrophotometer at 276 nm and 277 nm, respectively. The results indicate that agricultural soil as compared to barren soil is more efficient adsorbent for both insecticides, at optimum batch condition of pH 7. The equilibrium between adsorbate and adsorbent was attained in 12 hours. Methyl parathion is removed more efficiently (by seven orders of magnitude) than ethyl parathion. It may be attributed to more available binding sites and less steric hindrance of methyl parathion. Adsorption kinetics indicates that a good correlation exists between distribution coefficient (Kd) and soil organic carbon. A general increase in Kd is noted with increase in induced concentration due to the formation of bound or aged residue.

A New Integrated Photoreactor for Microwave Assisted Decolorization of Acid Orange 7 (AO7) in Aqueous Solutions

A new integrated photoreactor was assembled using a newly designed source, emitting both microwave power and UV radiation inside the reacting medium. The method is highly flexible and cheap, eliminating the need for the multimode and monomode microwave applicators, which are currently used for the excitation of a microwave electrodeless lamp. The characteristics of the source and the results from the decolorization of Acid Orange AO7 in an aqueous solution with hydrogen peroxide are presented. The decolorization process was carried out in batch condition and as continuous treatment and the effective reaction constant of the processes are reported. The experiments show that the photoreactor could be suitable for industrial application.