m. ghahraman afshar

The average consumption of raw water in Tarasht power plant is 2800 m3/day, which is considerable, and therefore it is necessary to provide effective solutions in order to improve the consumption pattern and prevent water wastage. After technical investigations, effective solutions such as recirculation of clean drains of boilers, drains of resin filters backwash, purification and recirculation of cooling tower drains, etc. were studied. Considering the volume and quality of the produced effluent of the power plant, the solution of recirculating clean drains was chosen as the most effective method. Among the various implementation methods of clean drain recycling, two methods of fountain pool and heat exchanger were investigated as two more effective technical and economic methods. Economic studies showed that for the provision of equipment and the implementation of 8 m3/h recycling solution of boiler blowdown, it is necessary to spend 1,070,000,000 Tomans for the fountain pool method and 1,425,630,000 Tomans for the heat exchanger method, that the fountain pool method needs about 25% less cost. Also, recirculation of boiler sludge (200 m3/day) to the raw water with the fountain method (functional efficiency 75%) leads to a 5.3% reduction in water consumption and the use of the heat exchanger method (functional efficiency 95%) leads to a reduction of about 6.8% of input raw water. In addition to the economic results, technical studies showed that the fountain pool method has more advantages than other methods of recirculating boilers due to the simplicity of operation, the possibility of removing iron and hydrazine.

Contamination of soil and water with heavy metal ions poses serious dangers and threats to the environment and human health, therefore it is very important to find an effective solution to remove these heavy metals from water. In this study, surface modified magnetic nanoparticles by N-phosphono-methylamino - diacetic acid with a core-shell structure were first synthesized. These nanoparticles were characterized. The performance of this synthetic nanoadsorbent for removing nickel (II), lead (II) and vanadium (V) ions from aqueous solutions was evaluated by various parameters such as adsorbent amount, contact time effect on adsorption rate and pH effect. The results show that the adsorption efficiency increases with raising pH and the best adsorbent performance in the adsorption process of nickel (II), vanadium (V) ions at pH = 6-7 and lead (II) at pH = 5-5.5 was observed. Also, the adsorption data were analyzed by the Langmuir and Freundlich isotherm model. In addition, the recyclability and reuse of the adsorbent shows that the adsorbent can be easily separated by using a magnetic magnet without any significant reduction in activity that can be used in successive metal ion adsorption-desorption cycles.

In this study, magnetic nanoparticles of MnFe2O4@SiO2 activated with N-phosphonomethyl amino di-acetic acid were synthesized with a core-shell structure. Moreover, the characteristics of surface functional groups, crystal structure, magnetic properties, size and surface morphology of these nanoparticles were investigated by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), microscope Scanning electrons (FESEM, Thermal Weight Analysis (TGA) and vibrating sample magnetometer(VSM). In this study, the antiscalant effect of precipitation for magnetic nanoparticles MnFe2O4@SiO2 were examined according to the reference test (NACE TM0374) by using 5 ppm MnFe2O4@SiO2. In this experiment, the precipitation effect of calcium sulfate and calcium carbonate on the surface of carbon steel was investigated. For this purpose, in one test a piece of carbon steel is placed in the presence of the precipitative compound and absence of antiscalant (control test) and in the other test of carbon steel is placed in precipitative compound with the antiscalant (main test) for a certain period of time. Afterwards, the amount of precipitation of the control and main experiment for carbon steel in the similar environment of the cooling tower of thermal power plants containing 1000 ppm sulfate and 500 ppm chloride were investigated. The tafel polarization test and impedance spectroscopy were used to measure the amount of fouling on the surface of the control and main carbon steel samples. The results indicate that the rate of precipitation formation is greatly reduced in the presence of antiscalant.

Paper turns yellow over time. Bleaching with oxidizing agents is one of the most common methods, which creates a colorless result by breaking down the light-absorbing chromophores. In this research, the changes in the properties of paper by applying oxidizing agents are studied. The paper samples were characterized by colorimetric, infrared spectroscopy, tensile, acidity, and SEM microscopes. Four oxidizing solutions were deployed for whitening the samples of Whatman paper using the Immersion method, including Hydrogen Peroxide (2 % V/V), Sodium Peroxide (2 % W/V), Potassium Periodate (2 % W/V), and Potassium Persulphate (2 % W/V) all solved in distilled water. The samples were treated within 48 hours, and characterizing tests were deployed. The results show that hydrogen peroxide with the highest tensile strength (17.75 Nm/g) and the lowest color difference (∆E= 1.48) after accelerated aging has the best performance among other samples. Also, hydrogen peroxide can be improved tensile strength, increase brightness, reduce yellowing, cause fibers stability, and keep the paper at an almost neutral acidity.