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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Particle Science & Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Span,quantitative size distribution,polydispersity
- چکیده:
- چکیده انگلیسی: Graphical size distribution is widely used in different fields of science and studies related to powders, droplets, bubbles, and pores. However, in some condition it may also be necessary to express the size distribution quantitatively. In spite of there being several suggested ways to quantify size distribution in the literature, some of these approaches are not applicable for many methods and the rest have other drawbacks. In this study, first, some quantitative size distribution methods (such as the polydispersity index) and their defects are concisely discussed. SPAN seems to be the most generally appropriate method, its parameters are determined from cumulative size distribution data. Nevertheless, some specific results imply that there are still some drawbacks in this method. Next, a new quantitative description of size distribution is presented which is applicable to many different techniques. In this method the characterization value is limited to 0 and 1, where 0 is related to completely polydispersed size distribution and 1 denotes the completely monodispersed size distribution.
- انتشار مقاله: 05-11-1397
- نویسندگان: Hamid Moghadam,Mozhgan Zakeri,Abdolreza Samimi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Renewable Energy and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: Microbial fuel cell,Ceramic Membrane,Domestic Wastewater,Gerischer element,constant phase element
- چکیده:
- چکیده انگلیسی: The effect of the thickness of ceramic membrane on the productivity of microbial fuel cells (MFCs) was investigated with respect to the electricity generation and domestic wastewater treatment efficiencies. The thickest ceramic membrane (9 mm) gained the highest coulombic efficiency (27.58±4.2 %), voltage (681.15±33.1 mV), and current and power densities (447.11±21.37 mA/m2, 63.82±10.42 mW/m2) compared to the 6- and 3-mm thick separators. The results of electrochemical impedance spectroscopy (EIS) analysis were investigated to identify the internal resistance constituents by proposing the appropriate equivalent electrical circuit. The Gerischer element was modeled as the coupled reaction, and diffusion in the porous carbon electrodes and the constant phase element was assimilated into the electrical double-layer capacitance. The thickest ceramic (9 mm) was found to have the largest ohmic resistance; however, owing to its superior barrier capability, it provided more anoxic conditions for better accommodation of exoelectrogenic bacteria in the anode chamber. Therefore, lower charge transfer, fewer diffusional impedances, and higher rates of anodic reactions were achieved. Excessive oxygen and substrate crossover through the thinner ceramics (of 6 and 3 mm) resulted in the suppressed development of anaerobic anodic biofilm and the accomplishment of aerobic substrate respiration without electricity generation.
- انتشار مقاله: 31-03-1398
- نویسندگان: Vajihe Yousefi,Davod Mohebbi-Kalhori,Abdolreza Samimi
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: optimization,Wastewater treatment,Membrane technology,Reuse,Bentazon
- چکیده:
- چکیده انگلیسی: Although bentazon is widely used as an agricultural herbicide, it is harmful to humans and poses many environmental threats. This study focused on the treatment of wastewater contaminated with bentazon pesticides using membrane technology. In this regard, low-pressure reverse osmosis (RO) was employed as it has already been used in the removal of other micro-pollutants. The effects of process variables on water flux and bentazon rejection were studied: temperature, pressure, and bentazon feed concentration. Based on central composite design (CCD), the quadratic model was engaged to correlate the process variables with the water flux and the bentazon removal responses. The obtained results showed that the bentazon rejection increased by enhancing the pressure while it decreased at higher feed solution concentration. However, with increasing temperature, the amount of bentazon removal was reduced. A bentazon rejection efficiency of 100 % could be achieved under optimum conditions (i.e., the temperature of 29.8 ℃ and hydrostatic pressure of 12.6 bar for a feed solution concentration of 66.9 mg/L). Therefore, reverse osmosis can effectively remove bentazon.
- انتشار مقاله: 01-03-1399
- نویسندگان: Mohammad Nematzadeh,Abdolreza Samimi,Soheila Shokrollahzadeh,Davod Mohebbi-Kalhori
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Biodegradation,Biofilter,Formaldehyde,Packing materials,Contaminated air
- چکیده:
- چکیده انگلیسی: The removal of formaldehyde from contaminated air was investigated via three laboratory-scale biofilters packed with different materials: a mixture of compost and woodchips (І), the natural clinoptilolite zeolite particles in the original form (II), and the mixture of zeolite/activated carbon (III). The biofilters were inoculated using aerobic sludge. The average removal efficiencies of 97.5%, 90%, and 93.5% were obtained at a 100 s empty bed residence time (EBRT) and 20 mg/m3 inlet concentration of formaldehyde for the biofilter of configurations І, II, and III, respectively. Also, the performance of the reactors was investigated at different EBRTs of 20, 30, 60, and 100 s, and the maximum elimination capacity of 2840 mg/m3.h was achieved at the lowest EBRT (20 s) for the biofilter of configuration II. Increasing the inlet formaldehyde concentration from 20 mg/m3 to 80 mg/m3 led to the maximum formaldehyde removal efficiency of 82% for the biofilter of configuration III. Therefore, a comparison of the results of the biofilters' performances showed that the biofilter of configuration III had the best performance, which was validated by obtaining a higher mass transfer coefficient. However, the biofilter of configurations II and III achieved steady-state conditions in a shorter time.
- انتشار مقاله: 26-09-1398
- نویسندگان: Elham Narooei,Davod Mohebbi-Kalhori,Abdolreza Samimi,Mortaza Zivdar
- مشاهده
- جایگاه : پژوهشی
- مجله: Advanced Journal of Chemistry-Section A
- نوع مقاله: Journal Article
- کلمات کلیدی: Heavy metal removal,Nano water treatment-clinoptilolite,Surfactant
- چکیده:
- چکیده انگلیسی: This work, the application of a surfactant-modified natural nano-clinoptilolite for the removal of several two valances heavy metal cations (i.e., Cu2+, Pb2+, Ni2+, Cd2+, Fe2+ and Zn2+) from aqueous media was discussed. Triton X-100 was used as modifier and to achieve maximum efficiency of adsorption; variables such as the concentration of surfactant, contact time, the working temperature and pH of sample solution were optimized. The results revealed that, the maximum adsorption was achieved at a solution with the pH of 6, containing 2 mL of triton X-100 and 2 g/L of clinoptilolite at 45 °C. The obtained selectivity series for the adsorption of cations were Pb2+>Cu2+>Cd2+>Ni2+ >Zn2+>Fe2+. The maximum adsorption capacity of the modified zeolite for Pb2+, Cu2+, Cd2+, Ni2+, Zn2+ and Fe2+ was 91.34, 85.71, 78.27, 76.18, 67.41 and 63.45 mg/g, respectively. The adsorption data were acceptably fitted to the both Freundlich and Langmuir isotherms.
- انتشار مقاله: 27-10-1398
- نویسندگان: Mohammad Reza Mirbaloochzehi,Alireza Rezvani,Abdolreza Samimi,Masoud Shayesteh
- مشاهده