Electrokinetic remediation of laterite soil contaminated by bisphenol A using sodium persulfate

• Main Authors: Min-Yang Hsu, 許閔揚
• Other Authors: LIAO,WEN-PIN
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/49783336932140852063

碩士 === 國立中興大學 === 環境工程學系所 === 104 === BPA is used widely in the industrial sector. That is commonly used endocrine disrupter substance in environment. Endocrine disrupter substances make some effects on human’s body such as reproductive system, endocrine system, thyroid, metabolism and cardiovascular. Electrokinetic is newer In-situ remediation process. It has a most effective treatment process for low permeability soil. Sodium persulfate is used commonly oxidant on In-situ chemical oxidation. Its physical and chemical properties are stable and high solubility. Sodium persulfate doesn’t produce other harmful substances after hydrolysis, but its oxidation rate is slowly, and need activated by light, heat, and transition metal. Persulfates is strong oxidant with a redox potential of 2.01 V, upon activation, persulfate can produce sulfate radicals (E0 = 2.6 V). This study prepares three kinds of soil and uses 0.5M HAc as the electrolyte. Soil 1, investigating removal effect when no iron in soil, added different SPS concentration in cathode reservoir. Soil 2 and Soil 3, investigating removal effect when soil contains iron, added different SPS concentration in cathode reservoir. Laterite is iron-rich soil. It proportionally added in Soil 2 and Soil 3, which contained 4.7 mg Fe/Kg and 9.4 mg Fe/Kg respectively. Group I (Test 1, Test 5, Test 7) is study different soil just uses 0.5M HAc to removal effect difference. As the results, the removal rates from solid phase were 51.12%, 53.52% and 55.86%, removal rates due to oxidation were 33.37%, 28.96% and 27.42%. When no added SPS in electrolyte, difference of removal rates is related to the solid phase and the composition of the soil. When the more kaolin content of the soil in the soil, the BPA adsorption increase and removal rates decrease. When no added SPS in electrolyte, a few BPA was oxidized and removed. The possible cause is that near the anode occurs electrolytic oxidation, then remove a few BPA by oxidation. Group II (Test 1 to Test 4) is to study Soil 1 added different SPS concentration in cathode with concentration from 0 to 1000 ppm. As the results, the removal rates from solid phase increase from 40.48% to 55.53%, and removal rates due to oxidation increase from 32.51% to 48.15%. Since there is no iron content in the soil 1, SPS only rely on electronic activate of the cathode, ferrous activate cannot be used. However, when added more than 500 ppm SPS that oxidation removal rates increase significantly over 10%. Group III (Test 7 to Test 12) is to study compare Soil 3 added different SPS concentration in cathode. With concentration from 0 to 4500 ppm. As the results, the removal rates from solid phase increase from 49.94% to 90.6%, and removal rates of oxidation increase from 27.42% to 78.43%. There is content 9.4 mg/kg iron in the Soil 3. When activated, SPS concentration increase the slid phase removal rates and oxidation removal rates. Group IV (Test 3, Test 6, Test 9) is to study compare removal rate of different iron content soil for using 0.5M HAc electrolyte and adding 500 ppm SPS in cathode. The results showed that removal rates from solid phase were 55.53%, 44.61% and 53.67%, oxidation removal rates were 48.15%, 24.61% and 37.98%, respectively. According to the result, 500ppm of SPS for soil had no significant treatment effect.