Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering) - Volume 12, Issue 4, 2019

Background: Gemini surfactants have good prospect of application development in various fields for their superior performance in foaming, wettability, and emulsification with lower critical micelle concentration (CMC) than conventional mono-surfactants. Objective: The purpose of this study was to synthesize an ionic sulfonate Gemini surfactant, which is mainly used as an oil flooding agent, to improve oil recovery and reduce oil production cost. Methods: With 4-dodecyl phenol, diethylene glycol and triethylene glycol as the raw materials to synthesize two sulfonate Gemini surfactants. The single factor experiment combined with Box-Behnken center composite experimental design, the optimum reaction conditions were determined. The optimal reaction condition of sulfonation was determined by orthogonal test. The product structure was characterized by nuclear magnetic resonance and infrared. Results: The mass fraction of sodium hydroxide ω(NaOH), temperature and the quality ratio of hexadecyl trimethyl ammonium bromide to dodecyl phenol were 18%, 93.5°C and 14.2%, respectively. Under the condition of ice bath, the molar ratio of chlorosulfonic acid to 4, 4- 12-12 alkyl phenol polyoxyethylene ether was 2.02:1 and reaction for 5h. The critical micelle concentration was determined to be 2×10-4, 1.05×10-4, respectively. Conclusion: Two sulfonate Gemini surfactants, namely 5, 5-dilauryl alkyl-2,2'-(diethylene glycol oxygen base) sodium diphenyl sulfonate and 5,5-dilauryl alkyl-2,2'-(triethylene glycol oxygen base) sodium diphenyl sulfonate (recorded as III and IV, respectively) were synthesized. The synthesized surfactants have excellent emulsification ability.

Background and Objective: Jute fiber is highly sensitive to the action of light. Significant features of the photochemical changes lose its tensile strength and develop a yellow color. It has been proved that the phenolic structure of lignin is responsible for the yellowing of jute fiber. In order to remove lignin, jute yarns were treated with laccase enzyme in different treatment times and ultrasonic powers. Lower whiteness index and higher yellowness index values were obtained by the laccase-ultrasound system in contrast to conventional laccase treatment. Methods: The laccase enzyme which entered the fibers by applying ultrasound, decreased the tensile strength while the loss in tensile strength was lower at high ultrasound intensities. FT-IR spectrum showed that the band at 1634 cm-1 assigned to lignin completely disappeared after laccase treatment in the presence of ultrasound. The absence of this peak in the laccase-ultrasound treated jute yarn suggests complete removal of lignin. Change in the morphology of fibers was observed by SEM before and after enzymatic delignification. The laccase-ultrasound treated yarns showed a rougher surface and more porosity. On the other hand, it was more effective in fibrillation of the jute fibers than the conventional method. Finally, bio-treated jute yarns were dyed with basic and reactive dyes. Results: The results indicated that at low intensities of ultrasound and relatively long reaction times, lignin can be more effectively removed and dye strength (K/S) increased to a higher extent. Laccase-ultrasound treatment increased the color strength by 33.65% and 23.40% for reactive and basic dyes respectively. Conclusion: In the case of light fastness, the conventional laccase treated yarns provided better protection than laccase-ultrasound treated yarns.

Background & Objective: The Manganous Dithionate (MnS2O6, MD) was formed during the flue gas desulfurization process over manganese ore slurry, which impeded the following valuable using of the desulfurized lixivium. In this study, the MD formation and restraint in the desulfurization process using manganese was carefully investigated. Methods & Results: Different type of manganese oxides/carbonate was used for the flue gas desulfurization, and the MD formation with the process was detected to obtain the basic information of the MD formation and restraint. The MD was directly formed by the uncompleted oxidation of SO2 with MnO2. The increased MD formation by Mn2O3, Mn3O4 and MnCO3 was due to their influence on the pH of slurry. Processability study showed that an increase in the acidity of slurry, the gaseous oxygen content and reaction temperature could inhibit the MD formation effectively. The optimum operating conditions to restrain the MD formation were temperature higher than 60°C, 10% or more oxygen and slurry pH lower than 3. The formed MD content was different with the different manganese compounds, which cloud be controlled by the ore-proportioning in industrial application. Conclusion: Using anolyte to prepare the manganese slurry for desulfurization could perform a good MD formation restraint, which provided valuable technical support for the cleaner production of electrolytic manganese industry.

Background: It is very important for understanding the turbulence drag-reducing mechanism and for improving product quality in the fields of pharmaceutical and chemical engineering to deeply investigate the rheological properties of surfactants solutions. Methods: The rheological properties of Cationic surfactant (Cetyltrimethyl Ammonium Chloride)/Sodium salicylate were measured and analyzed with the MCR302 rheometer. Results: The present results show that the shear viscosity of CTAC/NaSal solution with the exception of 0.9375mmol·L-1 can show the Newtonian characteristic, the shear-thickening, the shear-thinning and the stable shear properties with changing shear time. The induction time increases with a shear rate as a power law function relation tind=aγb. Conclusion: The shear viscosity of the CTAC/NaSal solution can be divided into three regions with shear rate, and its flow curve conforms to a linear function in the logarithmic coordinate. When the concentration and the shear rate are relatively high, the viscosity curve of the CTAC/NaSal solution appears "platform" at the high temperature. When the shear rate is greater than 90s-1, the shear viscosity only appears shear thinning with increasing temperature.

Background: Coal gangue was used as a catalyst in heterogeneous Fenton process for the degradation of azo dye and phenol. The influencing factors, such as solution pH gangue concentration and hydrogen peroxide dosage were investigated, and the reaction mechanism between coal gangue and hydrogen peroxide was also discussed. Methods: Experimental results showed that coal gangue has the ability to activate hydrogen peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions, after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%. Results: Both hydroxyl radical and superoxide radical anion participated in the degradation of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were also carried out via the continuous degradation experiment and ion leakage analysis. After five times continuous degradation, dye removal rate decreased slightly and the leached Fe was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope (SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD) indicated that coal gangue catalyst is stable after five times continuous reuse. Conclusion: The progress in this research suggested that coal gangue is a potential nature catalyst for the efficient degradation of organic pollutant in water and wastewater via the Fenton reaction.

Background and Objective: A model for the activated sludge aeration reactor is developed to study the effect of operating conditions on biodegradable organic pollutants treatment. Methods: The model was developed and fitted using an experimental study conducted for wastewater collected from meat processing industrial units in Egypt. Inlet biomass and substrate concentrations are the operating parameters considered in our study. Results: After treatment; biomass outlet concentration was reduced substantially. After reaching steady-state operation, outlet biomass concentration was not affected by the inlet biomass concentration, while outlet substrate concentration showed great dependency on the inlet substrate concentration. The model agrees well with the experimental data collected from an industrial activated sludge treatment unit. Conclusion: By varying process parameters, the model can be used effectively to predict and optimize the system behavior under different operating conditions. Varying the substrate concentration may lead to optimizing the process conditions for the system under study.