• Journal of Environmental Science International
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• v.12 no.4
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• pp.469-476
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• 2003

In order to examine the pre-treatment effect of crab shell en Pb$^{2+}$ removal by crab shell in aqueous solution, acid and alkali pre-treated crab shell were used. Electron microscopy techniques such as TEM (transmission electron microscopy) and SEM (scanning electron microscopy), and EDX (energy dispersive X-ray) and FTIR (Fourier transform infrared) spectrometry techniques were used to investigate the process of Pb$^{2+}$ removal by acid and alkali pre-treated crab shell. The Pb$^{2+}$ removal by acid pre-treated crab shell was much lower than that by untreated crab shell because of the decrease of CaCO$_3$ from the crab shell. However, the Pb$^{2+}$removal by alkali pre-treated crab shell increased compared to that by untreated crab shell. The results were confirmed by TEM, SEM, EDX and FTIR.nd FTIR.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.176-182
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• 2014

Using alkali treatment solution, neutrality treatment solution and acid treatment solution, the surface corrosion layer of copper plates and bronze plates that have been artificially corroded using HCl, $H_2SO_4$ and $HNO_3$ solutions were removed. In the case of alkali treatment solution, only air oxidation in the form of black tenorite and white cuproous chloride remained without being removed. In the case of using a neutrality treatment solution, a anhydrous type layer of reddish brown cupric chloride remained without being removed, together with this black and white corrosion substance. In the case of using an acid treatment solution, this red corrosion substance also remained, but all of the oxide was removed on the surface of the specimen that was treated by alternatively using alkali treatment solution and acid treatment solution. In the case of this treatment solution with the order of alkali-acid, oxidation no longer proceeded only through the distilled water cleaning process after treatment, thereby showing that oxidation from the cleaning solution no longer proceeded.

• Korean Journal of Agricultural Science
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• v.36 no.2
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• pp.225-232
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• 2009

The ratio of saccharification and formation of furans during the acid hydrolysis of agar with oxalic acid and sulfuric acid were examined base on the contents of the agar and acids. The ratio of saccharification in oxalic acid appeared to be 51~59% somewhat higher than 49~61% of sulfuric acid. Formation of the furans during the acid hydrolysis increased proportional to the contents of agar and acid. The relative formation ratio was high 10~47% for furfural (FUR) and 15~29% for hydroxy-methyl furfural (HMF) in 0.5~1.25% sulfuric acid rather than those of oxalic acid. When comparing the removal efficiency of the furans using an alkali treatment, steam stripping and hydrophobic resins, FUR was eliminated 60% by the alkali treatment, 62~90% by steam stripping and 71~75% by Amberlite XAD4 and 7HP, while HMF was removed to low levels of 10.5%, 4~17% and 13~25%, respectively. The loss of reducing sugar was also observed in process of the removal of furans, and the loss rate was the level of 2~4% in alkali treatment, 11~16% in steam stripping and 7~9% in Amberlite resins.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.2
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• pp.146-149
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• 1983

An experiment was made to investigate the effect of acid and alkali treatments obfserving the amount of nutrients especially calcium(Ca), phosphorus(P), ${\alpha}$-amino nitrogen(${\alpha}$-amino N), and total nitrogen(total-N)which were extracted from beef bone. 0~0.8% acetic acid and 0~0.5% sodium bicarbonate were used for treatment on different levels. The results are as follows; In case of acid treatment, Ca and P contents in bone stock wer observed to increase significantly according to acid concentration. Ca and P contents in bone stock highly incrased especially when the acid concentration was above 0.3%. Ca and P ratio varied from one to two when the acid concentration was below 0.01%. However contents of ${\alpha}$-amino N and total-N increased significantly when acid concentration was above 0.5%. In case of alkali treatment, contents of Ca and P did not increased significantly on all levels of sodium bicarbonate. The content of ${\alpha}$-amino N, however, increased significantly when the alkali concentration was in 0.05% but total-N did not show any variation in amount. These results suggest that acid treatment can give rise to an increase of the amount of nutrients which are extracted from beef bone but alkali treatment does not.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.5
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• pp.571-577
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• 2016

Phosphorus is an essential and irreplaceable element for all living organisms and its resource is limited. Significant amount of used phosphorus is collected in sewage treatment plant as sludge. Sludge ash after incineration contains about 10% of phosphorus in dry mass basis, which is comparable to phosphate rocks, and it is an important source of phosphorus recovery. Acid and alkali were used to leach phosphorus from sludge ash and compared for their leaching kinetics and performance. Phosphorus leaching by NaOH was fast and 0.2 N and 2 N NaOH leached 49% and 56% of the total phosphorus in the sludge ash at the L/S ratio of 100. Phosphorus leaching by sulphuric acid and hydrochloric were very fast and most of the phosphorus was leached in 5 minutes. In case of sulphuric acid 95% of the total phosphorus in the sludge ash was leached by 0.2 N at the L/S ratio of 100 and 93% was leached by 1 N at the L/S ratio of 10. 1 N hydrochloric acid leached 99% of the total phosphorus at the L/S ratio of 10. The results showed acids were more effective than alkali for phosphorus leaching from sludge ash and hydrochloric acid leached more phosphorus than sulphuric acid.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.5
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• pp.728-737
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• 1996

The purpose of this study is to investigate the change of the chemical properties of wool treated with six kinds of alkali (NaOH, Naac03, NH40H, NH2CH3CH30H, TMAH and BTMAH) with or without CTAB. Content of bound fatty acid liberated from wool surface, elemental composition and allw6rden time were measured to compare the surface modification of untreated and alkali treated wool. Also, the chemical degradation of the fiber was investigated by measuring cystine contents and urea-hydrogensulfite solubility. The result were as follows: 1. By the alkali treatment of wool, the covalently bound fatty acid of the epicuticle was removed and the allworden time was shortened, and in the case of wool treated with TMAH, BTMAH, the allw6rden sacs were formed unevenly and rarely. Also, cystine contents and urea-hydrogensulfite solubility were decreased by alkali treatment on wool. 2. The modification of epicuticle and the chemical degradation of wool were occurred due to alkaline hydrolysis in the order of TMAH, BTMAH > NaOH, Na3c03> NH2CH3CHaOH, NH40H. 3. As a treating time increased, the modification of epicuticle and chemical degradation of wool were accelerated. By the addition of CTAB to the alkali solution, the modification of epicuticle was increase, and the cystine contents and urea-hydrogensulfite solubility were reduced than that of wool teated with alkli without CTAB due to reduction of negative charge on the wool surface by the adhesion of CTAB.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1453-1457
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• 1999

The optimal conditions of alkali isomerization to obtain conjugated linoleic acid (CLA) concentrate from vegetable oils which have antioxidant and anticarcinogenic properties were studied. The result of alkali isomerization of various vegetable oils indicated that CLA content of safflower oil which contains more linoleic acid than any other vegetable oils was the highest of all experimental vegetable oils. During alkali isomerization, the amount of cis-9, trans-11 CLA and total CLA content in safflower oil was the highest at $8{\sim}11%$ KOH concentration and $180{\sim}185^{\circ}C$. But heating time had no effect on CLA formation after $20{\sim}40$ minutes. As a result of alkali isomerization of neutral lipid, glycolipid and phospholipid in safflower oil, CLA content of neutral lipid class was higher than any other lipid classes. By urea treatment and HPLC fractionation, total CLA content in alkali-isomerized safflower oil increased to 95.4% from 78.9%.

• Food Science and Preservation
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• v.6 no.3
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• pp.308-312
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• 1999

To develop the effective method for chestnut peeling, we examined the effect of peeling by acid and alkali treatment on their concentration, immersion temperature and time. Furthermore the physical properties of chestnut were investigated. In alkali treatment, 9% NaOH treated at 40$^{\circ}C$ for 9min was the most efficient for peeling outer peel, while acid treatment was less effective. But in the peeling of inner peel, acid treatment was more effective than alkali, especially, 3% HCIO$_4$ treated at 50$^{\circ}C$ for 30 min was the most effective. The correalation coefficient between weight and inner(outer) peel weight was higher than other physical properties, and multiple regression equation was established for predicting inner(outer) peel weight.

• Resources Recycling
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• v.2 no.2
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• pp.22-26
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• 1993

The flowsheet for the recovery of gallium and indium from zinc residues has been established based on the sulfuric acid treatment. In comparison with the alkali treatment, the method proposed in this work allowed the recovery of indium together with gallium. The majority of iron contained in leach liquor could be removed through the two-stage neutrallization under oxidative or reductive atmosphere. Crude gallium and indium could be obtained through the alkali and/or acid leaching of the products generated from the above treatment. In addition, cementation of indium with zinc powders could also be used for the concentration of it from weak acid solutions.

• Journal of the Korean institute of surface engineering
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• v.25 no.3
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• pp.144-149
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• 1992

The adsorption and molecular sieve characteristics of water, methanol, ethanol, butanol and benzene on acid-alkali treated natural zeolite from Kampo area were investigated by the Diamond·Kinter method, and it was compared with synthetic zeolite A. Adsorption amount of water increased with the treatment of acid rather than the treatment of alkali. Similar tendency was observedd in adsorption of alcohols such as methanol, ethanol and butanol, but the amount of adsorption decreased. From the views of the molecular size, adsorption amount of benzene decreased because of surface activity according to the cations species rather than chemical treatment. And it was almost same value that the amount of adsorption was compared acid treated natural zeolite with synthetic zeolite A.