• 한국환경보건학회지
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• 제33권1호
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• pp.68-74
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• 2007

The objective of this study is to examine the effect of the coagulation and homogenization in bulking sludge thickening of paper manufacturing plant using DAF(Dissolved Air Flotation) and gravitational sedimentation. The effects of parameters such as dosage of coagulant and homogenization time were examined. The results showed that DAF and sedimentation was affected aluminum sulfate and anion polymer coagulant differently. At the optimum dosage of aluminum sulfate, thickening efficiency of DAF and sedimentation process were increase 1.25 time and 2.02 time, respectively. At the optimum dosage of anion polymer coagulant, thickening efficiency of DAF process was increase 1.35 time, but thickening efficiency at sedimentation was 1.06 time. When anion polymer coagulant of 0.5 mg/l was added in DAF process, water content of sludge was decreased from 96.6% to 90.7% in dewatering process using Buchner funnel test device. After homogenization(20500 rpm, 10 min), Sauter mean diameter of sludge floc was decreased from 631 ${\mu}m$ to 427 ${\mu}m$, however increase of flotation efficiency by DAF was only 1.09 time.

• 한국환경과학회지
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• 제21권9호
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• pp.1043-1051
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• 2012

Coagulation, flocculation, and dissolved air flotation (DAF) experiments were performed with humic acid to evaluate the influence of operational conditions on removal efficiencies. We investigated coagulation, flocculation, and flotation conditions of humic acid removal using a laboratory-scale DAF system. This paper deals with coagulant type (aluminum sulfate and PSO-M) and the most relevant operational conditions (velocity gradients for coagulation and flocculation, retention time and recycle ratio and flotation time). Results showed that optimal conditions for removing humic acid, yielding CHA removal efficiencies of approximately 85 %, are a recycle ratio of 40 %, coagulant dosages of 0.15 - 0.20 gAl/gHA as aluminum sulfate and 0.03 - 0.12 gAl/gHA as PSO-M, coagulation($400s^{-1}$ and 60s), flocculation($60s^{-1}$ and 900s or more), and flotation(490 kPa or more and at least 10 min).

• Corrosion Science and Technology
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• 제12권5호
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• pp.215-219
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• 2013

Aluminum alloy(3003) can be dissolved during hydration process with hot tap water. In order to increase the stability of aluminum alloy, it was pretreated with anodization and phosphoric acid before hydration process. The effect of pretreatment on the surface property changes was analyzed with X-ray Photoelectron Spectroscopy (XPS) and Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES) and their results supported that the increase of hydroxyl group (-OH) on the surface formed during anodization and phosphorous acid treatment prevented the dissolution of aluminum alloy during hydration process at high temperature.

• 한국식품영양학회지
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• 제24권1호
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• pp.28-36
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• 2011

To investigate the protective effect of omija(Schizandra chinensis Baillon) tea extracts against the aluminum toxicity, Sprague-Dawley rats($100{\pm}10\;g$) were divided into 6 groups consisting of a control group, a 3% Schizandra chinensis Baillon tea plus extract group, a 1,000 and 2,000 ppm aluminum group, and a 1,000 and 2,000 ppm aluminum plus 3% Schizandra chinensis Baillon tea plus extract group. The rats administered aluminum were given 1,000 and 2,000 ppm of $Al_2(SO_4)_3$ dissolved in distilled water. The aluminum content in tissues from rats administered aluminum was lower than in the tissues of rats of administered aluminum plus 3% Schizandra chinensis Baillon tea in the water extract. Aspartate aminotransferase (AST) and alanine aminotransferase(ALT) levels were increased in the aluminum group and lower in the group receiving a 3% extract of Schizandra chinensis Baillon tea. Lactate dehydrogenase(LDHase) was lower in the group receiving a 3% extract of Schizandra chinensis Baillon tea plus aluminum than in the aluminum group. Cholinesterase(ChEase) was higher in the 3% Schizandra chinensis Baillon tea-aluminum group than in the aluminum group. Plasma levels of renin were increased in the aluminum group, compared to the group receiving 3% Schizandra chinensis Baillon tea plus aluminum. Plasma levels of aldosterone were increased in the aluminum group compared with the 3% Schizandra chinensis Baillon tea plus aluminum group. These results suggest that the group receiving Schizandra chinensis Baillon tea in water extract had a lowered level of aluminum accumulation, and it is believed that the Schizandra chinensis Baillon tea plus water had some protective effects against aluminum toxicity when administered in rats, but the mechanism of these effects remains obscure.

• 자원리싸이클링
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• 제15권5호
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• pp.52-56
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• 2006

국내 알루미늄 재생업체에서 알루미늄 용해시 발생되는 알루미늄 폐드로스를 사용하여 수처리응집제로 사용되는 폴리염화알루미늄(PAC: Poly Aluminium Chloride)를 제조하였다. 알루미늄 폐드로스를 염산과 반응시켜 폐드로스 중에 잔류하는 금속알루미늄을 PAC용액으로 제조함으로써 수산화알루미늄과 염산을 원료로 사용하여 PAC를 제조하는 종래의 방법에 비해 제품의 원료비를 줄일 수 있고, 알루미늄 폐드로스를 재활용함으로써 매립 등으로 폐기시켜야 할 폐드로스의 양을 줄이는 효과가 있다.

• 산업기술연구
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• 제21권A호
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• pp.351-355
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• 2001

This research was carried out to find out the possibility of using Faraday's law in analyzing the electrocoagulation system. Bench-scale reactor equipped with aluminum electrode plates was operated using synthetic wastewater which received sodium chloride for conductivity adjustment. Phosphate was added to the wastewater to induce the precipitation with Al. The amount of aluminum dissolved from the electrodes could be predicted by Faraday's law with a difference less than 5%. This difference was greater at a higher electric current, probably due to the increased solution temperature. However, effect of pH on the dissolution of the aluminum was negligible. The result of this study suggested that the operating condition of electrocoagulation system could be developed using the Faraday's law when the pollutant concentration is given.

• Environmental Engineering Research
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• 제10권2호
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• pp.45-53
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• 2005

Metal oxide particles with mole ratio of aluminum: titanium of 1:1 were synthesized by a sol-gel method. Langmuir (a) and Freundlich (b) adsorption isotherms of dissolved lead [Pb(Ⅱ)] ion on the metal oxide particles containing aluminum and titanium were determined as follows, respectively,(a) , (b) at pH 6where, correlation coefficients (R2) of Langmuir and Freundlich adsorption isotherms were 0.95 and 0.96, respectively.The overall adsorption rate of Pb(Ⅱ) on the metal oxide particles containing aluminum and titanium was determined by a differential bed reactor. The overall adsorption rate at pH 6 was as a following equation.at pH 6

• International Journal of Automotive Technology
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• 제7권4호
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• pp.485-492
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• 2006

The AA5182/polypropylene/AA5182(AA/PP/AA) sandwich sheets have been developed for application to automotive body panels in future lightweight vehicles with significant weight reduction. It has been reported that the AA5182 aluminum sheet shows $L\"{u}ders$ band because of dissolved Mg atoms that cause fabrication process problem, especially surface roughness. The examination of serration behavior has been made after the tensile deformation of the AA/PP/AA sandwich sheets as well as that of the AA5182 aluminum skins at room and elevated temperatures. All sandwich sheets and the AA5182 aluminum skin showed serration behavior on their flow curves. However, the magnitude of serration was significantly diminished in the sandwich sheet with high volume fraction of the polypropylene core. According to the results of the analysis of the surface roughness following the tensile test, $L\"{u}ders$ band depth of the sandwich sheet evidently showed lower than that of the AA5182 aluminum skin. The strain rate sensitivity, m-value, of the AA5182 aluminum skin was -0.006. By attaching these skins to the polypropylene core, which has relatively large positive value of 0.050, m-value of the sandwich sheets changed to the positive value. The serration mechanism of the sandwich sheets was quantitatively investigated in the point of the effect on polypropylene thickness variation, that on the strain rate sensitivity and that on the localized stress state.

• 한국표면공학회지
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• 제27권4호
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• pp.207-214
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• 1994

In consideration of global environmental protection and fuel saving, aluminum alloy sheets for auto body panels such as hood, fender etc., are expected one of the most promising materials for weight saving of cars. The chemical conversion coating is required to prevent the filiform corrosion occurring on painted aluminum. However the conventional process for the composited material mixed with aluminum and steel is complexs; aluminum part is chromated and assembled to the body, and then the steel body undergoes Zn phosphating. In order to overcome the low productivity due to the complex process and the environmental problem with a conventional process, a simultaneous zinc phosphating process for alsuminum and steel in an assembled condition is demanded. Newly developed phosphate solution has been investigated to characterize the phosphating behavior under various conditions. The optimum conditions of the phosphating solution for the application of the paint treatment derived as follows : about 0.3 for the ratio of Zn to $PO_4$, , 200~500 ppm for the concentration of fluoride ion, and 2.5~4.0 for pH. The concentration of dissolved aluminum ion must be kept below 2--ppm and suitable accelerator is found to be a mixture of 1g/$\ell$ $NO_2\;^-$, and 6g/$\ell$ $NO_3\;^-$.

• Nuclear Engineering and Technology
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• 제42권4호
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• pp.434-441
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• 2010

The activation products of aluminum and argon are key radionuclides for operational and environmental radiological safety during the normal operation of open-tank-in-pool type research reactors using aluminum-clad fuels. Their activities measured in the primary coolant and pool surface water of HANARO have been consistent. We estimated their sources from the measured activities and then compared these values with their production rates obtained by a core calculation. For each aluminum activation product, an equivalent aluminum thickness (EAT) in which its production rate is identical to its release rate into the coolant is determined. For the argon activation calculation, the saturated argon concentration in the water at the temperature of the pool surface is assumed. The EATs are 5680, 266 and 1.2 nm, respectively, for Na-24, Mg-27 and Al-28, which are much larger than the flight lengths of the respective recoil nuclides. These values coincide with the water solubility levels and with the half-lives. The EAT for Na-24 is similar to the average oxide layer thickness (OLT) of fuel cladding as well; hence, the majority of them in the oxide layer may be released to the coolant. However, while the average OLT clearly increases with the fuel burn-up during an operation cycle, its effect on the pool-top radiation is not distinguishable. The source of Ar-41 is in good agreement with the calculated reaction rate of Ar-40 dissolved in the coolant.