Evaluation of Carbon Aerogel Manufacturing Process in Order to Desalination of Saline and Brackish Water in Laboratory Scale

Carbon aerogel its fabrication and characterization and its uses in this process were studied for desalinating of saline and brackish water. The carbon aerogel manufacturing process involves the polymerization and pyrolysis of the mixture of resorcinol and formaldehyde. Carbon aerogels were analyzed using BET, BJH, and T-plot after construction. The effect of various parameters (including the influent salt concentration, the intensity of electric current flow, the distance between the electrodes and pH) on salt adsorption were studied. Analysis of BET/BJH shown that the surface of aerogel was 677.8 m2/g. much of porosity in the samples of carbon aerogel were between 1-2 nm, namely micro-pour and a similar level 0f 456 m2/gr is dedicated to micro-pour, with a correlation coefficient (r) equal to 94.5. According to the results, it seems that carbon aerogel electrodes have a good structure in desalination of brackish and saline water

An experimental investigation of proxy electrocoagulation process efficiency for COD removal from Azithromycin contaminated aqueous solution

Background and Aims: Pharmaceuticals are considered as emerging environmental pollutants due to their continuous input and persistence in the aquatic ecosystem even at low concentrations. This work focuses on the removal of chemical oxygen demand (COD) from Azithromycin contaminated synthetic aqueous solution through proxy electrocoagulation process.Materials and Methods: A batch method was used for removal of Azithromycin from water. The parameters affecting on the proxy electrocoagulation of antibiotics and subsequently COD removal efficiency such as reaction time, concentration of hydrogen peroxide, current density and pH of the solution was investigated.Results: The proxy electrocoagulation process achieved a very high COD removal efficiency (95.6%) with reaction time of 60 min, current density of 20 mA/cm-2 and at pH 3 in the presence of 1.5 mg/L of hydrogen peroxide, producing cleaned water.Conclusion: Although economically should be investigated compared to other methods, the studied process was useful in terms of Azithromycin removal from aqueous solutions.Key words: Wastewater, electrocoagulation, Azithromycin, CO

Evaluating the drinking waters microbial flora of reverse osmosis treatment systems in kashan city during summer and autumn (2015)

According to the various difficulties of Distillation desalination system,currently the membrane technology such as Reverse Osmosis (RO) is more useful. High concentration of dissolve solids in supplying water resources in Kashan caused a bad taste and reduced the consumer’s desire for using such water,and often they used treated water in a way that at the conducting time of this study,20 centers treated the water by RO method in the city. Therefore,this study evaluated the microbial flora of produced drinking water of RO treatment system in Kashan city during summer and autumn 2015. In this study the census method have used and the sampling have done from all the RO water treatment centers of the city. Three input,output and after storage,samples have taken. The evaluation of the temperature,residual chlorine,TDS,the storage time,and RO membrane operation time in samples have done. The HPC test has done on the samples in the laboratory and the positive plates have identified in terms of bacterial spices. The tests have repeated in four months of the year from July to October. The results showed 95% residual chlorine in the input samples and the HPC test for these samples showed no contamination. The sample contamination after treatment and the tank were 8 and 15% respectively. In addition,the most contamination level have related to September,which the samples temperature in this month reach its highest level. The Pearson coefficient results showed that there was a significant relation between the Heterotroph colonies number and the residual chlorine and temperature parameters,which was consistent with Karami et al. in Kermanshah and Dobaradaran et al. in Esfahan studies. In addition,there was a significant relation between the Heterotroph colonies number and storage time and RO membrane operation time

Performance of electrical stimulated anaerobic baffled reactor for removal of typical pollutants from low-strength municipal wastewater at low temperatures

Background: Although anaerobic system has been successfully used for treating the strong industrial wastewater, its efficiency for low-strength wastewater as municipal wastewater is not satisfying. This study aimed to enhance the capability of an anaerobic baffled reactor (ABR) for treating municipal wastewater. Methods: A 7-L ABR with 5 compartments was operated for a 287-day period fed with primary effluent from a wastewater treatment plant at 17 to 19°C. The study was conducted in 2 phases. In the first phase, the performance of ABR and in the second phase, the performance of ESABR (ABR integrated with an electrochemical system) were investigated. Results: The results of ABR operation indicated that at hydraulic retention time (HRT) =24 hours, the average removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total Kjeldahl nitrogen (TKN), total phosphorous (TP), and log reduction value (LRV) of coliforms were obtained to be 71%, 75%, 79%, 23%, 30.3%, and 5.8 Log, respectively. In this phase, when the HRT was decreased from 24 to 18 hours and from 18 to 14 hours, the removal efficiency of all parameters by the ABR was decreased. After the shift of ABR operation to ESABR, at HRT=24 hours and current density of 0.78 mA/cm2, the performance of the reactor was enhanced, so that the removal efficiency of BOD, COD, TSS, TKN, TP, and LRV of coliforms were achieved 16.8%, 15%, 4%, 10.7%, 49%, and 1 Log, which was greater than those obtained by ABR. Conclusion: According to the results, this technology (SEABR) is suitable for treating the low-strength municipal wastewater. Keywords: Wastewater, Anaerobic baffled reactor, Electrical stimulated, Treatmen

Investigation of Electrolysis Process Performance by Graphite Electrodes for De-Colorization of Phenolphthalein and Phenol Red from Aqueous Solution

This study elucidates the de-colorization of phenolphthalein and phenol red from aqueous solution through electrochemical oxidation technique. An electrochemical reactor had 1 liter volume that used 2 graphite electrodes. Effect of electric power voltage, inter electrode distance and electrolyte concentration was investigated in this system. It was found that the optimum conditions for completely removal of phenolphthalein was at voltage of 48 V, retention time of 9 minutes, distance between the electrode of 5 cm, and the salt concentration of 1.5 g/l. Also completely removal of phenol red was at voltage of 48 V, retention time of 8 minutes, distance between the electrode of 5 cm, and the salt concentration of 2 g/l. Phenol red and phenolphthalein COD removal efficiency was 85 and 80 percent respectively. The results suggest that the electrolysis process is an effective way to removal of phenolphthalein and phenol red color from effluent, because of it can completely remove the color in a short time

Determination of the Amount of Bioaerosols in Hospital Environments

 Background and Objective: Bioaerosols are particles of microbes, viruses and derivatives; they exist in a wide variety of shapes and sizes and can be measured with different air samplers. The purpose of this study is the determination of bacterial aerosol in the air of hospitals and the determination of contaminated areas for disinfection proceedings by hospital health care teams, by selecting the most appropriate and efficient system for air conditioning.Materials and Methods: This study was carried out at Tehran Ayatolah Taleghani Hospital. 35 most sensitive locations were chosen to reflect and be representative of the entire environment of the hospital. In the first phase, the three media were simultaneously put in the sampler each sample was repeated three times in the same conditions and then medium incubated in the incubator at a temperature of 37.2 degrees Celsius. After 24 or 48 hours, the numbers of colonies were counted. In the second phase the same locations were sampled again, at this stage, only thirty minute duration was sampled.Results: All problems were located in different parts of the women’s toilets. .The colonies grow in a gram positive and gram negative specific medium and comparison with the standard indicators status of these settings was evaluated.Conclusion: Bioaerosols can cause secondary hospital infections and this problem in patients with low immunity levels would be problematic. Factors such as humidity, sampling method, temperature, population, place and sampling time have a significant role in increasing the amount of bioaerosols in the air. REFERENCES1- Pasquarella C, Pitzurra O, Savino A. The index of microbial air contamination.Journal of hospital infection. 2000;46(4):241-56.2- Pant K, Crowe C, Irving P. On the design of miniature cyclones for the collection of bioaerosols.Powder Technology. 2002;125(2):260-53- Sillanpää M, Geller MD, Phuleria HC, Sioutas C. High collection efficiency electrostatic precipitator for in vitro cell exposure to concentrated ambient particulate matter (PM). Journal of Aerosol Science. 2008;39(4):335-47.4- Zhen S, Li K, Yin L, Yao M, Zhang H, Chen L, et al. A comparison of the efficiencies of a portable BioStageimpactor and a Reuter centrifugal sampler (RCS) High Flow for measuring airborne bacteria and fungi concentrations. Journal of Aerosol Science. 2009;40(6):503-13.5- Wu Y, Shen F, Yao M. Use of gelatin filter and BioSampler in detecting airborne H5N1 nucleotides, bacteria and allergens. Journal of Aerosol Science. 2010; 41(9):869-79.6- Griffiths W, Bennett A, Speight S, Parks S. Determining the performance of a commercial air purification system for reducing airborne contamination using model micro-organisms: a new test methodology. Journal of Hospital Infection. 2005;61(3):242-7.7- Durand KT, Muilenberg ML, Burge HA, Seixas NS. Effect of sampling time on the cultivability of airborne fungi and bacteria sampled by filtration. Annals of occupational Hygiene. 2002;46(1):113-8.8- Obbard JP, Fang LS. Airborne concentrations of bacteria in a hospital environment in Singapore.Water, Air, and Soil Pollution. 2003; 144(1-4):333-41.9- Li A, Liu Z, Zhu X, Liu Y, Wang Q. The effect of air-conditioning parameters and deposition dust on microbial growth in supply air ducts. Energy and Buildings. 2010; 42(4):449-54.10- Tang C-S, Chung F-F, Lin M-C, Wan G-H. Impact of patient visiting activities on indoor climate in a medical intensive care unit: a 1-year longitudinal study. American journal of infection control. 2009;37(3):183-8.11- Wan G-H, Chung F-F, Tang C-S. Long-term surveillance of air quality in medical center operating rooms.American journal of infection control. 2011;39(4):302-8.12- Vahdat K, Rezaee R, Gharibi O. 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Photocatalytic oxidation for antimicrobial control in built environment: A brief literature overview. Building and Environment. 2010;45(8):1747-54.18- Guan T, Yao M. Use of carbon nanotube filter in removing bioaerosols. Journal of Aerosol Science. 2010;41(6):611-20.19- Hwang GB, Jung JH, Jeong TG, Lee BU. Effect of hybrid UV-thermal energy stimuli on inactivation of< i> S. epidermidis</i> and< i> B. subtilis</i> bacterial bioaerosols. Science of the total environment. 2010;408(23):5903-9.20- Fletcher L, Noakes C, Beggs C, Sleigh P, editors. The importance of bioaerosols in hospital infections and the potential for control using germicidal ultraviolet irradiation. Proceedings of the First Seminar on Applied Aerobiology, Murcia, Spain, May; 2004. 

Solar photodegradation of carbamazepine from aqueous solutions using a compound parabolic concentrator equipped with a sun tracking system

The primary purpose of this study was to investigate the efficiency of a Compound Parabolic Concentrator (CPC) equipped with a sun tracking system in the photolysis of carbamazepine as a refractory organic compound. The natural sunlight experiments were accomplished during the period May–July 2017 in Tehran, Iran. The intermediate by-products of the process of solar photodegradation of carbamazepine (CBZ) were characterized using LC–MS. The results showed that increasing the reactor temperature did not significantly change CBZ degradation efficiency. However, the solution pH played a comparatively important role in CBZ solar photo degradation: removal efficiency increased considerably with pH from about 49% at pH 7 to almost 61% at pH 9. According to our findings, using a CPC reactor equipped with a sun tracker system promotes the solar photo-transformation rate of CBZ by 2-3 fold. In addition, LC/MS analysis showed that eight main intermediates were formed in the treated solution after solar photodegradation of CBZ. Therefore, complete mineralization of CBZ was not accomplished

Preparation, Characterization, and Application of N,S-codoped TiO2/Montmorillonite Nanocomposite for the Photocatalytic Degradation of Ciprofl oxacin: Optimization by Response Surface Methodology

An N,S-codoped TiO2/Montmorillonite nanocomposite, as a photocatalyst, was synthesized in the sol-gel method and used for the degradation of ciprofloxacin (Cip) in an aqueous solution. N,S-codoped TiO2/Montmorillonte was characterized by powder X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and X-ray fluorescence (XRF) analyzes. A central composite design (CCD) was used to optimize the variables for the removal of Cip by the N,S-codoped TiO2/Montmorillonite. A maximum decomposition of 92% of Cip was achieved in optimum conditions. The band gap value for the nanocomposite was 2.77 eV. Moreover, with the use of nanocomposite in the four consecutive runs, the final removal efficiency was 66%. The results show that the N,S-codoped TiO2/ Montmorillonite under simulated sunlight irradiation can be applied as an effective photocatalyst for the removal of Cip from aqueous solutions