• Advances in environmental research
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• v.5 no.2
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• pp.141-151
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• 2016

Large amounts of aluminum hydroxide ($Al(OH)_3$) exist in water purification sludge (WPS) because of the added aluminum coagulant in water treatment process. Notably, $Al(OH)_3$ is an amphoteric compound, can be dissolved in its basic condition using sodium hydroxide to form aluminate ions ($Al(OH)_4{^-}$). However, in a process in which pH is increasing, the humid acid can be dissolved easily from WPS and will inhibit the recovery and reuse of the dissolved aluminate ions. This study attempts to fix this problem by a novel approach to separate $Al(OH)_4{^-}$ ions using nanofiltration (NF) technology. Sludge impurity in a alkaline solution is retained by the NF membrane, such that the process recovers $Al(OH)_4{^-}$ ions, and significantly decreases the organic matter or heavy metal impurities in the permeate solution. The $Al(OH)_4{^-}$ ion is an alkaline substance. Experimental results confirm that a recovered coagulant of $Al(OH)_4{^-}$ ion can effectively remove kaolin particles from slightly acidic synthetic raw water.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.2
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• pp.263-269
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• 2002

This research was conducted to establish the efficient use of the colored rice bran fur dyeing textiles. To investigate the fabric dyeability of the colored rice bran extract, the anthocyanin pigments were extracted with water of different temperature ranges of 40 ~ 8$0^{\circ}C$ and were dyed on silk fabrics with different dyeing temperature $25^{\circ}C$~6$0^{\circ}C$, at acidic pH and neutral pH, respectively. Aluminum chloride was preheated with mordant K/S value and dyeing fastness of dyed silk fabrics were examined. The anthocyanins of the colored rice bran were stable and red color at acidic pH, red purple or purple blue at neutral pH, but unstable, blue color at alkaline pH. If extracting temperature and dyeing temperature of dyeing solution were higher, the dyeability was high, but the color of dyed fabric showed red tone. When extracting temperature was 8$0^{\circ}C$ and dyeing temperature of dyeing solution was 6$0^{\circ}C$, the dyeability was best. Without mordant, the dyeability of silk fabrics was higher in acidic pH than in neutral pH solution. With mordant, the dyeability was higher than without mordant, and also higher in acidic pH. Pretreatment of aluminum chloride resulted in the increase of color intensity and stability. The laundering fastness of dyed fabrics was good from grade 5 to grade 3-4. Because of the anthocyanins sensitivity on light radiation, the light fastness of dyed fabrics was poor from grade 3 to grade 1-2.

• Applied Biological Chemistry
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• v.19 no.1
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• pp.51-56
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• 1976

Chemical changes of dissolved $SO_2$ were followed in vitro system. Varying concentrations of sulfite solution reached similar Eh values 20 hours after preparation. No further increase of Eh values occurred in acidic solutions. Eh values were more greatly increased in neutral solutions than in alkaline solutions, and slightly higher in light than in dark. The decrease of measurable $SO_2$ content tended to be greater with increasing concentrations of sulfite, on exposure to light, and at higher pH values. A larger amount of hydrogen atoms was produced with higher concentrations of $SO_2$ and in neutral to alkaline solutions than in acidic solutions.

• Journal of the Korean Society of Costume
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• v.52 no.3
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• pp.19-27
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• 2002

This paper surveys the mordanting and dyeing properties of Sophora japonica L. Appropriate extraction, dyeing and mordanting condition of Sophora japonica L. were determined, and the effect of mordanting method on dye uptake and color fastness of dyed fabric was investigated. The maximum absorbance of Sophora japonica L. solution was 367.6mn, rutin solution was 365.6mn. The color of Sophora japonica L. solution was affected at pH 2 and pH 8~9. The optimum temperature to extract Sophora japonica L. was during 1 hour in 8$0^{\circ}C$. The effective dyeing temperature and time of silk were 10$0^{\circ}C$, 60min. K/S value of dyeing fabrics was increased by pre-mordanting treatment, especially Fe, Sn, Cr. In the case of Sophora japonica L. light fastness was increased by Fe mordanting. Perspiration fastness was better in acidic solution than that in alkaline solution. Fastness to rubbing and dry-cleaning were good in general.

• Journal of the Korean Chemical Society
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• v.13 no.2
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• pp.141-147
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• 1969

Organophosphorous compounds can be reduced by zinc metal in acidic solution after alkaline hydrolysis. Although phosphates and phosphonates did not evolve any gas, dithioates did evolve hydrogen sulfide and phosphine, thionates and thiolates did evolve only hydrogen sulfide. The evolved gases were qualitatively detected by means of lead acetate and silver nitrate or mercuric bromide papers and determined by spectrophotometrically. The reduction mechanism and analytical method of dithioates were proposed.

• KSBB Journal
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• v.10 no.4
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• pp.386-392
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• 1995

The high viscous ${\gamma}$-polyglutamic acid(${\gamma}$-PGA) from alkalophilic Alcaligenes sp. was purified and its solution property was investigated. The intrinsic viscosities for Na+ form and H+ form of ${\gamma}$-PGA were 31.1 and 0.38d$\ell$/g, respectively. The viscosity of H+-PGA was not influenced by pH or salts while that of Na+-PGA was influenced. The intrinsic viscosity of Na+-PGA solution decreased remarkably at the alkaline or acidic pH and showed the sharp decrease when salts were added. ${\gamma}$-PGA exhibited the property of the polyelectrolyte showing the .sharp decrease of intrinsic viscosity by the addition of NaCl, and intrinsic viscosity of dilute solution with the low concentration of NaCl was exponentially dependent on temperature and its temperature dependency increased with increasing NaCl concentration. The chain stiffness, coil overlap parameter and critical concentration of Na+-PGA were 0.08, 5.25 and 0.07g/d$\ell$, respectively.

• Textile Coloration and Finishing
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• v.7 no.2
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• pp.47-54
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• 1995

Safflower is natural red dye largely used for dyeing on cotton. It contains yellowish safflower yellow and reddish carthamin, whose constitution is known. Safflower yellow is water-soluble dye and carthamin is solved in alkaline condition. Carthamon obtained by adding acidic solution to a carthamin shows the original hue of safflower. In present study, the dyeing behavior of natural dye known as safflower are examined in an aqueous acidic medium by use of the different dyeing methods such as traditional, modern and purifide-powder method. The relationship between the dye-uptake of cotton fabric investigated by the three methods and the various dyeing conditions is discussed.

• Journal of Pharmaceutical Investigation
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• v.18 no.3
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• pp.125-131
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• 1988

This study was undertaken to investigate the proteolytic enzyme from Neungee mushroom [Sarcodon aspratus (Berk) S. Ito]. The proteolytic activity of Neungee was higher than other several edible mushrooms under various pHs. The potency of proteolytic enzyme of Neungee was same as the digestive drugs containing protease. So the proteolytic activity of the enzyme was increased in neutral or weak alkaline pH, whose characteristics would be alkaline protease. The specific activity of the purified enzyme obtained by using Tris acryl CM-cellulose ion exchange increased 20 times as compared with that of the crude extract. The proteolytic enzyme was stable at room temperature, but decomposition was fast when incubated at higher temperature more than $40^{\circ}C$. The half life of the enzyme was longest in neutral pH and rate constant was increased in acidic or alkaline solution.

• Journal of Surface Science and Engineering
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• v.49 no.6
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• pp.521-529
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• 2016

In this study, titanium nanotubes, prepared by anodization method, showing high surface and strong chemical stability in acidic and basic media, have been employed for the application to the electrodes for water splitting in KOH solution. Due to its high polarization resistance of $TiO_2$ itself, proper catalysts are essentially required to reduce overpotentials for water oxidation and reduction. Most of academic literature showed noble metal catalysts for foreign dopants in $TiO_2$ electrodes. From commercialization point of view, screening of low-cost catalyst is important. Herein, we propose molybdenum oxide as low-cost catalysts among various catalysts tested in the experiments, which exhibits the highest performance for hydrogen evolution reaction in highly alkaline solution. We showed that molybdenum oxide doped electrode can be operated in extreme acidic and basic conditions as well.

• Corrosion Science and Technology
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• v.17 no.3
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• pp.116-122
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• 2018

The secondary coolant of a nuclear power plant has small amounts of various impurities (S, Pb, and Cl, etc.) introduced during the initial construction, maintenance, and normal operation. While the concentration of impurities in the feed water is very low, the flow of the cooling water is restricted, so impurities can accumulate on the Top of Tubesheet (TTS). This environment is chemically very complicated and has a very wide range of pH from acidic to alkaline. In this study, the characteristics of the oxide and the mechanism of stress corrosion cracking (SCC) are investigated for Alloy 690 TT in alkaline solution containing Pb, Cl, and S. Reverse U-bend (RUB) specimens were used to evaluate the SCC resistance. The test solution comprises 3m NaCl + 500ppm Pb + 0.31m $Na_2SO_4$ + 0.45m NaOH. Experimental results show that Alloy 690 TT of the crevice environment containing Pb, S, and Cl has significant cracks, indicating that Alloy 690 is vulnerable to stress corrosion cracking under this environment.