Journal of Iranian Chemical Engineering (Farsi Edition)
Year:2022 | Volume:21 | Issue:122|Papers Count:7

In this research, the efficiency of the photocatalytic process of zinc oxide nanoparticles in removing Basic Red 46 azo dye from the aqueous solution has been investigated in a batch system, exposed to UV light with a power of 15 W. Also, the number of samples and data analysis were predicted using design expert software. According to the results, with increasing the initial concentration of the dye solution, the percentage of photocatalytic degradation decreases, and with enhancing the catalyst concentration to an optimal value equal to 1 g/L, the removal efficiency of the dye increases. In addition, the percentage of dye removal is directly related to the duration of radiation. According to the analysis of the results in the design expert software, the maximum removal of the Basic Red 46 azo dye was obtained at pH =11 and the contaminant concentration was 45 mg/L with an amount of 0. 61 g/L of zinc oxide as catalyst in 86 minutes.

Injection rate shape has an important effect on the performance of internal combustion engines. In this study, the effect of three triangular injection rate shapes, including left triangle, middle triangle, and right triangle, which were distinguished by the parameter a equal to 0, 0. 5, and 1, respectively, on the performance of a Reactivity Controlled Compression Ignition (RCCI) engine were investigated and compared with the square injection rate shape. It was realized that by increasing, the gross indicated efficiency (GIE) and nitrogen oxides (NOx) emissions increased, while unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions decreased. The highest GIE and the lowest UHC and CO emissions were obtained by the right triangle, which were 9. 9% higher and 27. 45% and 25. 51% lower than those obtained by the square injection rate shape, while the lowest NOx emissions were obtained by the left triangle, which was 14. 15% lower than that obtained by the square injection rate shape.

Porous polymer particles containing internal and external pores have a very large specific area, relatively low density, permeability and excellent adsorption capacity. The structure of pores (porosity, pore size, specific area) are the main factors governing the application of such materials in various catalyst fields, separation, solid phase extraction, ion exchange, sensors storage and drug delivery. Extensive applications of porous particles are forcing researchers to develop conventional methods such as suspension polymerization, dispersion, precipitation, seed sweeling polymerization and new membrane / microchannel and microfluidic emulsification methods. In all these methods, different porogen are used in the first stage, followed by the removal of the porogen to produce pores. In this study, all different polymerization techniques for the preparation of porous polymer particles with spherical and non-spherical structure, functionality are reviewed and the advantages and disadvantages of each method in terms of particle properties and particle size distribution are mentioned.

Recently, supercritical fluids have been introduced as a suitable environment for extraction. Supercritical carbon dioxide is one of the most commonly used supercritical fluids due to its cheapness, toxicity, inseparability, environmental compatibility, and extraction operations at low temperatures. Low critical temperatures of carbon dioxide have led to its widespread use as a suitable solvent for temperature-sensitive substances such as food and pharmaceuticals. In this study, using supercritical carbon dioxide, extraction of active compounds of Eryngium Billardieri was investigated. In this regard, experiments were conducted on operating the pressure (110, 130 and 150 times), temperature (35, 40 and 45 ° C), time (30, 50 and 70 minutes), and the particle size (0. 075, 0. 1, and 0. 2 mm) using Taguchi design in Minitab software. The highest efficiency was obtained under operating conditions of 40 ° C, the pressure of 150 bar, the particle size of 0. 075 mm, and the time of 50 minutes. Also, using GC-MS test data, the most synthesized material is Di Iso Octyl Ester.

The increase demands for energy and consequent depletion of fossil fuels resulted in various environmental issues such as air pollution. So, finding clean and renewable energy sources is critical. Diesel as a fossil fuel is excessively used in diesel engines which led to the emission of greenhouse gas and depletion of these resources, as well. Therefore, looking for an appropriate energy source for diesel engines is necessary. In this context, use of the third generation of biofuels, or microalgae, not only makes it possible to produce fuel from a sustainable, renewable, and biocompatible energy source, but also can be combined with wastewater treatment and carbon dioxide fixation. Considering the importance of biodiesel production, in this work, the main effective parameters on biodiesel production from algae sources, including algae growth, methods for algae harvesting, methods for extraction of oil from algae, and various processes involved in biodiesel production using the oil extracted from algae were reviewed. In addition, in the end, the characteristic futures of the biodiesel from algal sources for application as fuel are comprehensively discussed.

In this study an efficient, relatively simple and fast method based on the extraction of organic gas steam liquid extraction (OGS-LE) was presented for extraction and determination of trace amounts of lead in aqueous solutions. For this purpose, ammonium pyrrolidine dithiocarbamate (APDC) as a complexing agent and methyl isobutyl ketone (MIBK) as extracting solvent was used, Also, the effect of parameters on the extraction recovery such as the volume of organic solvent, the molar ratio of the extracting agent relative to lead metal, the pH of the aqueous phase, the extraction time and the temperature of the heating chamber were investigated. Determination of number of experiments, statistical analysis of data and optimization of lead ion extraction were performed using central composite design (CCD) and response surface methodology (RSM). Under optimal conditions, the limit of detection (LOD) and limit of quantification of the method (LOQ) are 0. 13 μ gL− 1 and 0. 43 μ gL− 1, respectively, the relative standard deviation is 3. 7 percent and the analysis curve is linear in the range of 0. 5 to 10 μ gL− 1.