تاثير شدت بخشي با محلول كلسيم كلريد بر مكانيسم هاي الكتروليز و الكترواسمزي خاك رسي در فرآيند الكتروسينتيك

Impact of Enhancement with Calcium Chloride Solution on the Electrolysis and Electro-Osmosis Mechanisms of Clayey Solis in Electrokinetics Process

از اﻟﮑﺘﺮوﺳﯿﻨﺘﯿﮏ ﺑﺮاي رﻓﻊ آﻟﻮدﮔﯽ، اﻓﺰاﯾﺶ زﻫﮑﺸﯽ ﺳﯿﺎل ﺣﻔﺮهاي، و ﺑﻬﺒﻮد وﯾﮋﮔﯽﻫﺎي ﻣﻬﻨﺪﺳﯽ ﺧﺎكﻫﺎي رﺳﯽ اﺳﺘﻔﺎده ﻣﯽﺷﻮد. در ﺧﺎك-ﻫﺎي ﺣﺎوي ﮐﺮﺑﻨﺎت ﺑﻪ ﻋﻠﺖ ﻇﺮﻓﯿﺖ ﺑﺎﻓﺮﯾﻨﮓ ﺧﺎك، ﺟﺒﻬﻪ اﺳﯿﺪي ﺑﻪ ﻃﻮر ﮐﺎﻣﻞ ﺷﮑﻞ ﻧﻤﯽﮔﯿﺮد و رﻓﻊ آﻟﻮدﮔﯽ از ﺧﺎك، زﻫﮑﺸﯽ ﺳﯿﺎل ﺣﻔﺮهاي، و ﺑﻬﺒﻮد وﯾﮋﮔﯽﻫﺎي ﻣﻬﻨﺪﺳﯽ ﺧﺎك ﺻﻮرت ﻧﻤﯽﮔﯿﺮد. ﻫﻤﯿﻦ ﻣﻮﺿﻮع ﺳﺒﺐ ﮐﺎﻫﺶ ﺟﺮﯾﺎن اﻟﮑﺘﺮواﺳﻤﺰي و ﻋﺪم ﻋﻤﻠﮑﺮد ﻣﻨﺎﺳﺐ روش اﻟﮑﺘﺮوﺳﯿﻨﺘﯿﮏ ﻣﯽﺷﻮد. ﯾﮑﯽ از روشﻫﺎي ﻣﻘﺎﺑﻠﻪ ﺑﺎ اﯾﻦ ﻣﺸﮑﻞ، اﺳﺘﻔﺎده از روش ﺷﺪتﺑﺨﺸﯽ اﺳﺖ. ﻫﺪف اﯾﻦ ﭘﮋوﻫﺶ ﺗﻌﯿﯿﻦ اﻣﮑﺎن اﻓﺰاﯾﺶ ﺟﺮﯾﺎن اﻟﮑﺘﺮواﺳﻤﺰي در ﺑﻪ ﮐﺎرﮔﯿﺮي روش ﺷﺪتﺑﺨﺸﯽ ﺑﺎ اﺳﺘﻔﺎده از ﻣﺤﻠﻮل ﮐﻠﺴﯿﻢ ﮐﻠﺮﯾﺪ در ﻓﺮاﯾﻨﺪ اﻟﮑﺘﺮوﺳﯿﻨﺘﯿﮏ ﺧﺎك رﺳﯽ ﭘﺮﮐﺮﺑﻨﺎت اﺳﺖ. در اﯾﻦ راﺳﺘﺎ ﻧﻤﻮﻧﻪ رﺳﯽ ﻃﺒﯿﻌﯽ ﭘﺮﮐﺮﺑﻨﺎت ﺗﺤﺖ ﻓﺮاﯾﻨﺪ اﻟﮑﺘﺮوﺳﯿﻨﺘﯿﮏ در دو ﺣﺎﻟﺖ ﺑﺪون ﺷﺪتﺑﺨﺸﯽ و ﺷﺪتﺑﺨﺸﯽ ﺷﺪه ﺑﺎ ﻣﺤﻠﻮل ﮐﻠﺴﯿﻢ ﮐﻠﺮﯾﺪ در ﻏﻠﻈﺖﻫﺎي 0/2 و 0/5 ﻣﻮﻻر ﮐﻪ ﺑﻪ ﻣﺨﺰن ﻣﻮﺟﻮد درﻣﺠﺎورت اﻟﮑﺘﺮود آﻧﺪ اﺿﺎﻓﻪ ﺷﺪﻧﺪ، آزﻣﺎﯾﺶ ﺷﺪ. ﻧﺘﺎﯾﺞ ﺣﺎﮐﯽ از آن اﺳﺖ ﮐﻪ ﺑﻪ دﻟﯿﻞ ﺣﻀﻮر درﺻﺪ ﻗﺎﺑﻞ ﺗﻮﺟﻪ ﮐﺮﺑﻨﺎت ﮐﻠﺴﯿﻢ در ﺧﺎك، ﻧﻪ ﺗﻨﻬﺎ pH ﻧﻬﺎﯾﯽ ﺧﺎك در ﻓﺮاﯾﻨﺪ اﻟﮑﺘﺮوﺳﯿﻨﺘﯿﮏ ﮐﺎﻫﺶ ﻧﯿﺎﻓﺘﻪ ﺑﻠﮑﻪ ﺣﺘﯽ ﺑﻪ ﻋﻠﺖ ﺣﺎﮐﻢ ﺷﺪن ﺟﺒﻬﻪ ﺑﺎزي در ﺣﻀﻮر ﮐﺮﺑﻨﺎت ﮐﻠﺴﯿﻢ و ﮐﻠﺴﯿﻢ ﮐﻠﺮﯾﺪ در ﺳﺎزوﮐﺎر اﻟﮑﺘﺮوﻟﯿﺰ، ﻣﻘﺎدﯾﺮ pH ﺧﺎك اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻪ اﺳﺖ. ﺑﺎ اﯾﻦ وﺟﻮد در آزﻣﺎﯾﺶﻫﺎ ﺷﺪت ﺑﺨﺸﯽ داده ﺷﺪه ﺑﺎ ﻣﺤﻠﻮل ﮐﻠﺴﯿﻢ ﮐﻠﺮﯾﺪ، ﺣﻀﻮر ﯾﻮن ﮐﻠﺴﯿﻢ و اﻓﺰاﯾﺶ ﻓﺮاﯾﻨﺪ اﻧﺘﻘﺎل اﻟﮑﺘﺮو ﯾﻮﻧﯽ، ﺳﺒﺐ اﻓﺰاﯾﺶ ﺷﺪت ﺟﺮﯾﺎن و ﺑﺎزده ﺳﺎزوﮐﺎر اﻟﮑﺘﺮواﺳﻤﺰي ﺷﺪهاﺳﺖ. ﺑﻪ ﮔﻮﻧﻪاي ﮐﻪ دﺑﯽ اﻟﮑﺘﺮواﺳﻤﺰي ﻧﻤﻮﻧﻪ ﺷﺪت ﺑﺨﺸﯽ ﺷﺪه ﺑﺎ 0/5 ﻣﻮﻻر ﮐﻠﺴﯿﻢ ﮐﻠﺮﯾﺪ ﻧﺴﺒﺖ ﺑﻪ ﻧﻤﻮﻧﻪ بدون شدت بخشي در انتهاي آزمايش افزايش 250 درصدي داشته است.

Electrokinetics is known as a common method for improvement of soil engineering properties and contaminant removal from soils. In carbonated soils due to the soil buffering capacity, the acid front does not form through the soil sample. Therefore, the soil improvement usually caused by hydrogen ion effect will not occur. Consequently, a reduction in electrokinetics efficiency happens. One of the methods to overcome this problem is the application of enhancement methods. In this paper the influence of enhancement by the use of calcium chloride solution on two mechanisms of electrolysis and electro osmosis in electrokinetics remediation of carbonated clay is experimentally investigated. For this purpose, an un enhancement and enhance electrokinetics process with 0.2, and 0.5 molar concentrations of calcium chloride has been applied on carbonated natural clay samples. The calcium chloride solutions were added to anode reservoir. The achieved results of this paper indicate that due to the noticeable percentages of carbonate calcium in soil sample, not only the pH of soil in electrokinetics process has not decrease, but also because of alkaline condition of soil sample due to the presence of calcium carbonate and calcium chloride solution, the pH of soil has increased. Furthermore, in enhancement electrokinetics with calcium chloride, the presence of calcium ions and an increase in electro migration process have caused an increase in efficiency of electro osmosis. For this reason, the volumetric flow rate of enhanced electrokinetics experiments with 0.5 molar calcium chloride has been almost 250% more than that of for un-enhanced experiments.