پديد آورندگان :
براتي فردين، علي دانشگاه تربيت مدرس - دانشكده فني و مهندسي , خدادادي دربان، احمد دانشگاه تربيت مدرس - دانشكده فني و مهندسي - گروه فرآوري مواد معدني , جمشيدي زنجاني، احمد دانشگاه تربيت مدرس - دانشكده فني و مهندسي - گروه فرآوري مواد معدني
كليدواژه :
الكتروكينتيك , كنترل pH , افزايش ولتاژ , عامل هاي بهبود دهنده , كروزين
چكيده فارسي :
آﻟﻮده ﺷﺪن ﺧﺎك ﺑﻪ ﺗﺮﻛﻴﺒﺎت ﻫﻴﺪروﻛﺮﺑﻨﻲ در ﻧﺘﻴﺠﻪ ﺣﻮادث ﮔﻮﻧﺎﮔﻮن و ﻧﺸﺖ ﺗﺮﻛﻴﺒﺎت ﻫﻴﺪروﻛﺮﺑﻨﻲ ﺑﻪ ﻣﺤﻴﻂ ﻣﺘﺨﻠﺨﻞ ﺟﺎﻣﺪ ﺧﺎك آﺛﺎر اﺟﺘﻨﺎب ﻧﺎﭘﺬﻳﺮي در ﻣﺤﻴﻂ زﻳﺴﺖ از ﺧﻮد ﺑﻪ ﺟﺎي ﺧﻮاﻫﺪ ﮔﺬاﺷﺖ. روشﻫﺎي ﭘﺎﻛﺴﺎزي ﻣﺘﻌﺪدي ﺑﺮاي ﺧﺎك آﻟﻮده ﺑﻪ ﺗﺮﻛﻴﺒﺎت ﻫﻴﺪروﻛﺮﺑﻨﻲ وﺟﻮد دارد،اﻟﻜﺘﺮوﻛﻴﻨﺘﻴﻚ ﻳﻜﻲ از روشﻫﺎي ﻣﻮﺛﺮ ﭘﺎﻛﺴﺎزي و ﻣﻘﺮون ﺑﻪﺻﺮﻓﻪ از ﻧﻈﺮ ﻫﺰﻳﻨﻪ و زﻣﺎن ﺑﺮاي ﻣﺤﻴﻂﻫﺎي ﺟﺎﻣﺪ و ﻣﺘﺨﻠﺨﻞ رﻳﺰداﻧﻪ ﻛﻪ ﻇﺮﻓﻴﺖ ﺟﺬب ﺑﺎﻻي رﻃﻮﺑﺖ و ﻫﻤﭽﻨﻴﻦ آﻻﻳﻨﺪهﻫﺎي آﻟﻲ را ﺑﻪ ﺧﻮد دارﻧﺪ ﻣﺤﺴﻮب ﻣﻲﺷﻮد. از ﺟﻤﻠﻪ ﺗﺮﻛﻴﺒﺎت ﻫﻴﺪروﻛﺮﺑﻨﻲ ﻫﻴﺪروﻓﻮب ﺑﺎ وﻳﮋﮔﻲﻫﺎي ﻓﻴﺰﻳﻜﻲ و ﺷﻴﻤﻴﺎﻳﻲ زﻳﺎن آور ﺑﺮ اﻛﻮﺳﻴﺴﺘﻢ و ﺟﺬب ﺑﺎﻻ ﺑﺮ ﻣﺤﻴﻂ آب و ﺧﺎك ﺑﻪ ﻛﺮوزﻳﻦ ﻣﻲﺗﻮان اﺷﺎره ﻧﻤﻮد. اﻳﻦ ﻣﺎده در ﺗﺮﻛﻴﺐ ﺧﻮد داراي ﻫﻴﺪروﻛﺮﺑﻦﻫﺎي ﻣﺘﻔﺎوت ﺑﻮده و ﻫﺮ ﻣﻠﻜﻮل آن ﺑﻪ ﻃﻮر ﻣﺘﻮﺳﻂ داراي 10 ﺗﺎ 16 اﺗﻢ ﻛﺮﺑﻦ اﺳﺖ. ﭘﺎﻳﺪاري و ﻣﺎﻧﺪﮔﺎري ﻳﻜﻲ از وﻳﮋﮔﻲﻫﺎي ﺑﺎرز اﻳﻦ ﺗﺮﻛﻴﺐ در اﻛﻮﺳﻴﺴﺘﻢ از ﺟﻤﻠﻪ ﻣﺤﻴﻂ ﺧﺎك اﺳﺖ. ﺧﺎك اﺳﺘﻔﺎده ﺷﺪه در اﻳﻦ ﭘﮋوﻫﺶ از ﺟﻨﺲ ﺧﺎك ﻛﺎﺋﻮﻟﻴﻨﻴﺖ رﻳﺰداﻧﻪ، ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻣﺎﻫﻴﺖ و اﺛﺮﺑﺨﺸﻲ روش اﻟﻜﺘﺮوﻛﻴﻨﺘﻴﻚ ﺑﺮاي ﻣﺤﻴﻂ ﻣﺘﺨﻠﺨﻞ اﺳﺘﻔﺎده ﺷﺪ. در اﻳﻦ ﭘﮋوﻫﺶ ﺑﻪ ﻣﻨﻈﻮر دﺳﺘﻴﺎﺑﻲ ﺑﻪ زﻣﺎن ﺑﻬﻴﻨﻪ، ﻧﻮع ﻣﺤﻠﻮل اﻟﻜﺘﺮوﻟﻴﺖ و ﻋﺎﻣﻞ ﺑﻬﺒﻮد دﻫﻨﺪه ﻣﻨﺎﺳﺐ ﺑﺮاي ﺗﻠﻔﻴﻖ ﺑﺎ روش اﻟﻜﺘﺮوﻛﻴﻨﺘﻴﻚ 5 آزﻣﺎﻳﺶ ﺷﺎﻣﻞ اﺳﺘﻔﺎده از روش اﻟﻜﺘﺮوﻛﻴﻨﺘﻴﻚ ﻃﻲ ﻣﺪت زﻣﺎن 5 و 7 روز، روش اﻟﻜﺘﺮوﻛﻴﻨﺘﻴﻚ در ﻣﺪت 7 روز ﺑﻪ ﻫﻤﺮاه دو ﻧﻮع ﻣﺤﻠﻮل اﻟﻜﺘﺮوﻟﻴﺖ ﻣﺘﻔﺎوت و ﻋﺎﻣﻞﻫﺎي ﺑﻬﺒﻮد دﻫﻨﺪه ﻛﻨﺘﺮل pH و اﻓﺰاﻳﺶ وﻟﺘﺎژ ﺑﺎ ﺗﻠﻔﻴﻖ روش اﻟﻜﺘﺮوﻛﻴﻨﺘﻴﻚ در ﻧﻈﺮ ﮔﺮﻓﺘﻪ ﺷﺪﻧﺪ. درﺻﺪ ﺣﺬف ﻛﺮوزﻳﻦ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻣﺪت زﻣﺎن 5 و7 روز ﺑﺎ اﺳﺘﻔﺎده از ﻣﺤﻠﻮل اﻟﻜﺘﺮوﻟﻴﺖ ﻧﻴﺘﺮات ﭘﺘﺎﺳﻴﻢ ﺑﻪ ﺗﺮﺗﻴﺐ ﺑﺮاﺑﺮ 47/24 و 50 ﺑﻮد. ﺑﺎ اﻓﺰاﻳﺶ 2/9 ﺑﺮاﺑﺮي ﺟﺮﻳﺎن اﻟﻜﺘﺮواﺳﻤﺰ در ﻣﺪت زﻣﺎن 48 ﺳﺎﻋﺖ از 5 ﺑﻪ 7 روز راﻧﺪﻣﺎن ﺣﺬف ﻛﺮوزﻳﻦ 2/76 درﺻﺪ اﻓﺰاﻳﺶ ﭘﻴﺪا ﻛﺮد. اﺳﺘﻔﺎده از آب ﻣﻘﻄﺮ ﺑﻪ ﻋﻨﻮان ﻣﺤﻠﻮل اﻟﻜﺘﺮوﻟﻴﺖ در ﻣﺪت 7 روز راﻧﺪﻣﺎن ﺣﺬف را ﺑﻪ 33/02 درﺻﺪ ﻛﺎﻫﺶ داد. اﻣﺎ ﻫﻨﮕﺎم اﺳﺘﻔﺎده از ﻋﻮاﻣﻞ ﺑﻬﺒﻮد دﻫﻨﺪه ﻛﻨﺘﺮل pH و اﻓﺰاﻳﺶ وﻟﺘﺎژ ﺗﺎ 2 وﻟﺖ ﺑﺮ ﻫﺮ ﺳﺎﻧﺘﻲ ﻣﺘﺮ راﻧﺪﻣﺎن ﺣﺬف ﻛﺮوزﻳﻦ ﺑﻪ ﺗﺮﺗﻴﺐ ﺑﺎ ﺟﺮﻳﺎن اﻟﻜﺘﺮواﺳﻤﺰ 372 و 452 ﻣﻴﻠﻲﻟﻴﺘﺮ ﺑﻪ 47/69 و 61/43 درﺻﺪ اﻓﺰاﻳﺶ ﭘﻴﺪا ﻧﻤﻮد. ﭘﺲ ﺑﻬﺘﺮﻳﻦ راﻧﺪﻣﺎن ﺣﺬف ﻛﺮوزﻳﻦ ﻣﺮوﺑﻂ ﺑﻪ اﺳﺘﻔﺎده از روش اﻟﻜﺘﺮوﻛﻴﻨﺘﻴﻚ ﺑﺎ ﺗﻠﻔﻴﻖ ﻋﺎﻣﻞ ﺑﻬﺒﻮد دﻫﻨﺪه اﻓﺰاﻳﺶ وﻟﺘﺎژ و اﺳﺘﻔﺎده از ﻣﺤﻠﻮل اﻟﻜﺘﺮوﻟﻴﺖ ﻧﻴﺘﺮات ﭘﺘﺎﺳﻴﻢ ﻃﻲ ﻣﺪت زﻣﺎن 7 روز ﺑﻮد.
چكيده لاتين :
Every year with the expansion and development of industrial and mining activities, millions of tonnes of toxic waste are produced throughout the world. Soil contamination by organic material as a result of various incidents and the leakage of organic compounds into the soil solid porous media will have an adverse effect on the environment. There are several methods for soil remediation contaminated with hydrocarbon compounds. Electrokinetic is one of the effective remediation which includes three main mechanisms for remediation, electroosmotic flow, ionic migration and electrophoresis. Electrokinetic is suitable in terms of cost and time for solid and porous fine-grained environment media that have high adsorption capacity of moisture and also organic pollutants. Kerosene is considered as one of the hydrophobic organic compounds with harmful physical and chemical properties to ecosystems and high adsorption onto the water and soil media. It has different hydrocarbons in its composition, each molecule having an average of 10 to 16 carbon atoms. It is so durable in the ecosystem, including the soil environment. The soil used in this study was fine-grained kaolinite due to the nature and effectiveness of the electrokinetic method for porous media. In this study, five series of experiments were carried out using electrokinetic method and its combination with improved techniques. The parameters including cumulative electroosmotic flow, electrical current intensity, reservoir and soil pH variation and residual kerosene concentrations in soil were studied. The highest electrical current devoted to increased voltage and pH control tests with 48 and 94 mA respectively for a time interval of 80 to 90 hours after the start of the tests were observed. The higher electric current intensity causes faster migration of ionic species to the opposite-electrode, resulting in greater electroosmotic flow transportation. In the present study, the removal percentage of kerosene from kaolinite soil through the different electrokinetic techniques including changing the electrolyte solution (nitrate potassium and tap water), increasing the-voltage (2 volts per cm of soil), and pH control over 5 and 7 days were investigated. Results revealed, using potassium nitrate as electrolyte solution, the the removal efficiency of kerosene was 47.24% and 50%, respectively, according to the remediation time of 5 and 7 days. With an increase of 2.9 times in the electroosmotic flow over a period of 48 hours from 5 to 7 days, the removal efficiency of the kerosene increased by 2.76%. Using distilled water as electrolyte solution despite the volume of 555 milliliters of electroosmotic flow, kerosene removal efficiency decreased to 33.02% in 7 days. The percentage of kerosene removal by pH control and increased voltage up to 2 v/cm, respectively with electroosmotic flow of 372 and 452 was 47.69 and 61.43%. Hence, a higher volume of electroosmotic flow represents a greater removal of kerosene in the soil. According to the obtained results, the best removal efficiency of kerosene (inspite of higher electroosmotic flow in tests with no enhancement technique) was due to the use of electrokinetic method by combining the higher voltage enhancement technique and the use of potassium nitrate electrolyte as solution over a period of 7 days.
