جستجوی مقالات مرتبط با کلیدواژه « water treatment » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

In this research, the nanofibrous polystyrene /titanium dioxide nanotube (PS/TiO2 nanotubes) membrane was prepared by electrospinning method. In order to synthesize titanium dioxide nanotubes, the anodizing method was used. Then, the effect of different weight percentages of titanium dioxide nanotubes on the performance of the resulting membranes was investigated. The nanoparticles and nanocomposites prepared in this research were analyzed using several analyses, including fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FE-SEM), along with X-ray energy diffraction spectroscopy (EDS). The thermal behavior and crystal structure of prepared nanocomposite membranes were investigated using (TGA) analysis and X-ray diffraction (XRD), respectively. Afterward, in order to investigate the prepared structures, analyses such as porosity measurment, water contact angle, swelling and water flux of the membranes were performed. The photocatalytic property of the prepared membranes toward decomposition of methylene blue was investigated by two methods. The obtained results demonstrated that the dye removal was accomplished in the best way in the static method (using the membrane as an absorbent) for 48 hours. The prepared nanocomposite membranes were also used in the dye filtration removal process and the best result was obtained by using the membrane containing titanium dioxide nanotubes with the concentration, 0.05 g/(V(50).

In this study, a new composite adsorbent based on dolomite mineral, coated with chitosan and graphene oxide was fabricated and used for removal of methylene blue (MB) from water. The effects of time, initial MB concentration, pH and temperature on the adsorption capacity of the fabricated composite adsorbent in the removal of MB as a cationic dye were investigated. The obtained results were analyzed by Freundlich and Langmuir isotherm models as well as pseudo first and second order kinetic models. The results of adsorption experiments showed that the fabricated composite adsorbent for removing MB follows the Langmuir adsorption isotherm model and the pseudo second order kinetic model. According to the Langmuir isotherm, the maximum monolayer adsorption capacity of MB on the surface of the composite adsorbent is equal to 3.746 mg/g. This adsorbent has a higher adsorption capacity at high temperatures and alkaline pHs.

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 Today, with the development of different indus tries and the disposal of untreated was tewaters, environmental pollution and pollution of water resources are increasing very rapidly. Membrane technology is an advanced and hopeful way to treat water and was tewater. Nanofiltration technology is widely used in water treatment and desalination of seawater.

The performance of thin film polyamide membranes containing unmodified and modified manganese dioxide nanotubes was inves tigated. After hydrothermal synthesis of manganese dioxide nanotubes, the inner surface of the nanotubes was modified with polydopamine, and then, their performance in thin film polyamide membranes (in terms of monovalent/divalent ions rejection and permeation flux) was inves tigated.

Unmodified and modified nanotubes were characterized by Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and X-ray diffraction analysis (XRD). In addition, the morphology and s tructure of the thin film membranes were inves tigated by FESEM tes t and the performance of the membranes was s tudied in terms of permeation flux, contact angle and rejection of sodium and copper ions. The maximum pure water flux, 18.6 L/m2h, was obtained for the membrane containing 0.10 %wt modified nanotube; an increase of 21.88% compared to the neat membrane. Creation of tiny pores on the surface of the membranes through hydrophilic nanotubes resulted in higher flux while there are extra routes through the nanotubes for water permeation. The maximum rejection of sodium ion (97.02%) for the membrane containing 0.2 %wt modified nanotubes could be related to the s tacking of the nanotubes and more spatial hindrance, reduction in the diameter of the nanotube due to the coating and permeation of water through the nanotubes.

Nowadays, the facts such as papulation growth, climate change, development in industries e.g. (textile industry) and so on threaten the water resources. Waste water which produces by industries contains millions of organic compounds which is so dangerous to ecology and human health.  To solve this important issue, researchers carried out a huge number of studies on it and suggest various solutions including water recycling and water treatment. Water treatment is classified in four major aspects such as chemical, physical, biological and advanced oxidation process method ( AOP) . Among them, advanced oxidation process and the use of materials like photo catalysts  have received great attention due to their low cost and high efficiency.  Among photo catalysts, MOFs are assumed as the new generation of porous materials which are utilized due to the degradation and adsorption behavior, the feasibility of synthesis, and high chemical and physical resistance. This paper aims to investigate the water treatment process using MOFs.

This study deals with modelling of aerating - permeation process for removal of VOCs from wastewater. The hybrid process allows desorbed VOCs from aerating process to be subsequently recovered using a membrane based vapour permeation process. A mathematical model has been developed to describe the mass transfer in both processes based on the resistance in series model. The separate evaluation of feed phase and membrane phase resistances has been carried out at different feed hydrodynamic conditions in a constant membrane thickness. A sensitivity analysis has been carried out using the developed model to investigate the effects of operational factors such as temperature, pressure, feed concentration, gas and liquid flow rate on separation performance of the process. As typical cases, removal of four VOCs, i.e. 1,2-dichloroethane (DCE), 1,1,2-Trichloroethane (TCE), Chloroform and Dichloromethane from water was investigated in a hybrid process consist of a stripping column of 90 cm height and vapour permeation unit employing PDMS membrane with an effective area of 14.7 cm2. The results indicated that while the gas phase resistance was negligible in air stripping process, it played a significant role in vapour permeation process, especially in feed side. The modelling results demonstrated that the air/water ratio has a great impact on the removal efficiency of air stripping process, but it should be limited to prevent flooding. The examination of the hybrid model has shown that the hybrid process has high efficiency for high concentrations, high gas flow rates and optimal temperature.