en تخصصي Special مقاله اصیل Original Article <div style="text-align: justify;"><span class="fontstyle0">Background: </span><span class="fontstyle2">Industrial dyes are toxic and carcinogenic, therefore, they should be removed from wastewater. The aim of this study was to investigate the removal of acid orange 7 Dye from wastewater using ultraviolet (UV) radiation, MgO nanoparticles, ultrasonic method alone and in combination with each other.</span><br> <span class="fontstyle0">Methods: </span><span class="fontstyle2">The effects of some factors such as temperature, pH, hydraulic retention time (HRT), UV power, and concentration of MgO nanoparticles on the removal of Acid Orange 7 dye from synthetic wastewater using different methods were investigated. Also, adsorption isotherms for MgO nanoparticles and kinetics for UV radiation were investigated.</span><br> <span class="fontstyle0">Results: </span><span class="fontstyle2">The optimum HRT was 55 minutes while the temperature was not effective in dye removal using the ultrasonic method. Under optimum conditions for UV irradiation method (HRT = 70 minutes, UV power = 170 mW/cm</span><span class="fontstyle2" style="font-size:5pt;">2</span><span class="fontstyle2">, and temperature = 10˚C), 58% of the dye was removed. However, under optimum conditions for MgO nanoparticles method (HRT = 15 minutes, temperature = 20˚C, and ratio of MgO nanoparticles to the initial dye concentration = 67.2), 82% of the dye was removed. By combining these methods, the dye removal efficiency was significantly increased. The combination of ultrasonic method and MgO nanoparticles had no significant effect on increasing the dye removal efficiency from wastewater. It was revealed that dye removal using UV radiation can be described by the first-order kinetics.</span><br> <span class="fontstyle0">Conclusion: </span><span class="fontstyle2">According to the results, UV radiation has a synergistic effect on the dye adsorption process by MgO nanoparticles. Therefore, the combination of these methods can be effective for the removal of dye from wastewater.</span></div> Azo compounds, Ultraviolet rays, Ultrasonic method, Nanoparticles, Waste water, Kinetics 157 170 http://ehemj.com/browse.php?a_code=A-10-1-143&slc_lang=en&sid=1 Amirreza Talaiekhozani amirtkh@yahoo.com 10031947532846005535 10031947532846005535 Yes Corresponding author: Department of Civil Engineering, Jami Institute of Technology, Isfahan, Iran Abbas Heydari Chaleshtori abbas.heidary8070@gmail.com 10031947532846005536 10031947532846005536 No Department of Chemical Engineering, Jami Institute of Technology, Isfahan, Iran Farhad Banisharif f.banisharifdehkordey@gmail.com 10031947532846005537 10031947532846005537 No Department of Research and Development, Nirouchlor, Isfahan, Iran Zeinab Eskandari medi_esi2000@yahoo.com 10031947532846005538 10031947532846005538 No Department of Chemical Engineering, Jami Institute of Technology, Isfahan, Iran Mohammad Nasiri mohammadnasiri@yahoo.com 10031947532846005539 10031947532846005539 No Department of Chemistry, Faculty of Applied Science, Malek Ashtar University of Technology, Isfahan, Iran Farham Aminsharei aminsharei.fa@gmail.com 10031947532846005540 10031947532846005540 No Department of Safety, Health and Environment, Najafabad Branch, Islamic Azad University, Najafabad, Iran Junboum Park Junbpark@snu.ac.kr 10031947532846005541 10031947532846005541 No Department of Civil and Environmental Engineering, Seoul National University, Seoul, South Korea Shahabaldin Rezania shahab_rezania89@yahoo.com 10031947532846005542 10031947532846005542 No Department of Environment and Energy, Sejong University, Seoul, South Korea Maryam Bazrafshan maryambazrafshan1993@gmail.com 10031947532846005543 10031947532846005543 No Department of Chemical Engineering, Jami Institute of Technology, Isfahan, Iran