• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.94-102
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• 2015

Electro-coagulation experiments were conducted with aluminum (Al) or iron (Fe) electrode in order to determine the optimal electrode material and operation conditions for algae removal. Al electrode showed higher removal rate of algae than Fe electrode because Al flocs have positive surface charges which electrostatically attract algae species having negative surface charges. Removal rate of algae and total phosphorous (T-P) was increased as current density and electrode area increases. It was also found that initial pH with neutral range was optimum for T-P removal by electro-coagulation. Bench-scale continuous flow experiments consisted of electro-coagulation reactor, agitation tank and settling tank were conducted. In electro-coagulation reactor, a large fraction of Al flocs were distributed to scum layer, due to the gas bubbles generated by electrolysis reaction. In agitation tank, most of Al flocs were settled and the optimal mixing intensity was found to be 50 rpm to achieve good settleability. The removal rate of algae was about 90-95%. Additionally, the removal rate of the T-P and COD was observed to be $73.8{\pm}8.0%$ and $75.0{\pm}3.8%$, respectively. Meanwhile, the removal rate of total nitrogen (T-N) was relatively low at only 24%.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.819-823
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• 1995

Thin films of two kinds of Prussian Blue (PB)-modified, using iron(Ⅲ) complex instead of conventional FeCl3, were prepared on a gold substrate and these films were able to be electrochemically reduced in potassium nitrate solution. In case of PB-modified films prepared from Fe(Ⅲ)-ethylenediamine-N,N'-diacetic acid (FeEN3+)/K3Fe(CN)6 solution, the mid-peak potential was 0.156 V in 0.1 M KNO3 and it was found that potassium ion migrates into or out of the film during the electrolysis. These films were shown to be electrochromic. These films exhibited smaller peak separation than those formed from Fe(Ⅲ)-tartaric acid (FeTA3+)/K3Fe(CN)6 system. The diffusion coefficient of Fe(CN)63-/4- redox couple, evaluated using the fabricated Au rotating disc electrode(rde) previously reported, was in good agreement with the existing data. Two experimental procedures, including the voltammetry at relatively low scan rates and the rde study, have been used in order to characterize the electrode kinetics. The electrode kinetics of some redox couples (FeEN2+-FeEN3+ and FeTA2+-FeTA3+) on both PB-modified thin films and bare Au electrode were studied using a Au rde. In all cases the rate constants of electron transfer obtained with the PB-modified film electrodes were only slightly less than those obtained for the same reaction on bare Au disc electrodes. The conductivities, as determined from the slopes of the i-V curves for a ca. 1 mm sample for dried PB-modified potassium-rich and deficient bulk samples pressed between graphite electrodes, were 6.21 × 10-7 and 2.03 × 10-7(Ω·cm)-1, respectively.