The present work establishes in depth study of ultrasound assisted preparation of performic acid (PFA) in a continuous flow microstructured reactor. The influence of various parameters viz. formic acid: hydrogen peroxide molar ratio, flow rate, temperature and catalyst loading on the PFA formation were studied in a continuous flow microstructured reactor. In a continuous microstructured reactor in the presence of ultrasonic irradiation, the formation of PFA was found to be dependent on the molar ratio of formic acid: hydrogen peroxide, flow rate of reactants, temperature and catalyst loading (Amberlite IR-120H). The optimized parameter values are 1:1M ratio, 50mL/h, 40°C and 471mg/cm respectively. Further, the performance of Amberlite IR-120H catalyst was evaluated for three successive cycles in continuous microstructured reactor. The performance of catalyst was found to be decreased with the usage of the catalyst and is attributed to neutralization of the sulfonic acid groups, catalyst shrinkage, or loss in pore sites. The experimental results revealed that, for an ultrasound assisted synthesis of PFA in continuous microstructured reactor the observed reaction time was even less than 10min. The observed intensification in the PFA synthesis process can be attributed to the intense collapse of the cavities formed at low temperature during ultrasonic irradiations, which further improved the heat and mass transfer rates with the formation of HO during the reaction. The combined use of ultrasound and a continuous flow microstructured reactor has proved beneficial process of performic acid synthesis.
Ultrasonic cavitation induced degradation of Congo red in aqueous solution was investigated for a variety of operating conditions. It is found that the degradation of Congo red in aqueous solution follows pseudo-first-order reaction kinetics and the degradation rate is dependent on the initial concentration of Congo red, the temperature and pH of the aqueous medium. The effects of Fe 2+ and Fenton reagent addition on the sonochemical degradation of Congo red were also investigated. The results obtained here indicate that the degradation rate of Congo red in aqueous solution was substantially accelerated by Fe 2+ , NaCl or Fenton reagent addition.
The present paper reports the experimental details for the synthesis of performic acid (PFA) using Corning advanced-flow reactors (AFRs) using formic acid and H
CuO nanocomposites with different Ce3+ doping concentrations (0, 0.5, 1.0, 1.5, 3.0 and 5.0 mol.%) were synthesized by PEG-200 assisted facile sonochemical method. The as-synthesized composites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-visible absorption spectroscopy. Further, these composites were evaluated for photodegradation activities towards MB dye under sunlight irradiation. The XRD results demonstrated that CuO nanocomposites exhibits monoclinic phase and the crystallinity decreases with increasing Ce 3+ doping concentration. The as-synthesized nanocomposites exhibited vesicular morphology with diameters ranging from 50 to 100nm. UV-visible absorption spectra results demonstrated that these nanocomposites exhibit strong absorption in the visible region and the absorption intensity increases with increasing Ce 3+ doping concentration. The photocatalytic experiments using assynthesized nanocomposites for degradation of Methylene blue (MB) dye revealed that, compared to undoped CuO; Ce 3+ doped CuO nanocomposites exhibited improved photodegradation ability. The photodegradation rate was maximum for 3.0 mol% Ce 3+ doped CuO which showed 98% degradation within 180 mins under sunlight irradiation. Recycling experiments demonstrated good stability of as-synthesized nanocomposites even after threere cycles.
The present work deals with the investigation of the greener route for the production of silver nanoparticles using Raphanus sativus (R. sativus) bioextract in a continuous flow tubular microreactor. The parameters affecting the particle size and distribution were investigated. From the results obtained it can be inferred that the ascorbic acid (reducing agent) present in the R. sativus bioextract is responsible for the reduction of silver ions. At optimum condition, the particle size distribution of nanoparticles is found between 18[Formula: see text]nm and 39[Formula: see text]nm. The absorbance value was found to be decreased with an increase in the diameter of the microreactor. It indicates that a number of nuclei are formed in the micrometer sized (diameter) reactor because of the better solute transfer rate leading to the formation of large number of silver nanoparticles. The study of antibacterial activity of green synthesized silver nanoparticles shows effective inhibitory activity against waterborne pathogens, Shegella and Listeria bacteria.
The present chapter highlights the kinetic studies for the sonochemical synthesis of peracetic acid (PAA) in a batch reactor. The effect of different operating parameters including acetic acid to hydrogen peroxide molar ratio, temperature, catalyst loading, effect of ultrasound, were studied using Amberlite IR-120H as a catalyst. The deactivation of the Amberlite IR-120H catalyst has also been studied. The experimental data were further utilized for the estimation of intrinsic reaction rate constants and equilibrium constants. From the experimental results; the optimized PAA concentration was observed for 471 mg/cm 3 catalyst loading at 40°C with acetic acid to hydrogen peroxide molar ratio equals to 1:1 in the presence of ultrasound. Results also revealed that the reaction rate was found to be significantly enhanced in the presence of ultrasound, which can be attributed to the enhanced mixing and in-situ formation of H 2 O 2 . The use of ultrasound drastically reduces the overall reaction time to 60 min, which is very less compared to 30 h as reported for conventional batch reactor utilizing H 2 O 2 only.
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