• Journal of Korean Society of Forest Science
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• v.79 no.4
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• pp.376-387
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• 1990

A research effort has been made to determine soil buffer capacity in forest soils nearby urban and industrialized regions. Buffer capacities of soils from four regions were measured by different pH levels of artificial acid precipitation. The following conclusions have been drawn in response to the overall research objectives. Soil Suffer capacity was the highest in Kangwondo followed by Uisan, Yeochon and Seoul when simulated acid precipitation were treated at the level of pH 3.0-5.7. With the acid precipitation treatment below pH 2.0 level, however, the capacity dropped seriously with no significant differences between the regions. In Kangwondo region soils weathered from granite and limestone showed significant differences in the buffer capacities. Soil collected in Seoul and Ulsean revealed that the capacities tended to increase with the distance from the pollution sources when treated at pH 3.0, 4.5 and 5.7 level of acid precipitation. The major mechanism of soil buffer observed during simulated acid precipitation experiment was canon exchange for Kangwondo forest soils. In Seoul region canon exchange also played an important role in soil buffering under artificial acid precipitation between 3.0 and 5.7 pH levels, yet under pH 2.0 level aluminum and silicate hydrolysis. In Ulsan canon exchange was a msjor determinant for the buffer capacity above pH 4.5 level, between pH 3.0-4.5 aluminum hydrolysis and below pH 3.0 aluminum and silicate hydrolysis. In Yeochon silicate hydrolysis led buffer capacity above pH 4.5 and below pH 4.5 aluminum hydrolysis.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.422-430
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• 2000

Three-year-old Pinus koraiensis seedlings, transplanted in brown forest soils originating from granite were treated with simulated acid rain of pH concentrations 5.6(control), 4.0, 3.0, 2.5 and 2.0 for 210 days from April 21 to November 17, 1999. Visible injury of the seedlings were observed at the pH 2.0 and pH 2.5 treatments. The total dry weight of the seedlings decreased at pH 2.0 treatment compared with that of the control, and T/R ratio increased at pH 2.0 treatment compared with others. The elements in each part of the seedlings, concentrations of Ca, P and content of chlorophyll in needles increased at the pH 2.0 treatment compared with the control. The concentration of N in the needles of the seedlings increased as the soil pH decreased. As the treated pH was lowered, soil pH has decreased, and concentrations of Ca, Mg, Al, and Mn increased, especially at pH 4.4. In addition, there was a strong correlation(r=0.90, p<0.05 ; r=-0.94, p<0.01) between the dry weight of the seedlings and the pH and Al concentration of the soils. Therefore, the pH and Al concentration in the soil may be useful indicator for assessing the effect of acid rain on the growth of woody plants.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.843-850
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• 1994

Polyphosphazene-bound Wittig reagents such as $[NP(OC_6H_5)_{1.7}(OC_6H_4P(Ph)_2$=$CHCH_2CH_2CH_3)_{0.3}]_n$ were synthesized by treating $[NP(OC_6H_5)_{1.7}(OC_6H_4Br)_{0.3}]_n$ with n-butyllithium, diphenylchlorophosphine, and n-butyl iodide. Polymeric reactions were carried out according to the reaction conditions with cyclic primers such as [$N_3P_3(OC_6H_5)_5(OC_6H_4P(Ph)_2$)]. The desired alkene and polymer-bound phosphine oxide were prepared successfully by the reaction of polyphosphazene-bound Wittig reagents with benzophenone.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.296-303
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• 1993

Response surface methodology was employed to investigate the conditions for separating water-soluble proteins from egg yolk using sodium alginate, propylene glycol alginate (PGA), sodium carboxymethylcellulose (CMC) and pectin which are approved as food additives. Effects of plysaccharide concentration and pH of the reaction system on protein and lipid contents in the supernatant were evaluated at respectively five and three levels of concentration and pH using rotatable hexagon design. Statistical analysis showed that pH of the system was a more important factor than polysaccharide concentration as it significantly affected all two responses. Separating conditions established by a graphical optimization technique were $0.23{\sim}0.25%$ of sodium alginate at $pH\;5.9{\sim}6.0$, $0.15{\sim}0.17%$ of PGA at $pH\;4.3{\sim}4.5$, $0.30{\sim}0.25%$ of CMC at pH 3.0, and $0.09{\sim}0.10%$ of pectin at $pH\;5.6{\sim}5.8%$.

• Korean Journal of Microbiology
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• v.19 no.3
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• pp.121-127
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• 1981

The constituents of molasses and effect of pH precipitate formation in molasses solution, vary according to its producing districts. The formation of precipitation is not so changeable in the range of buffering zone of molasses solution(pH4.3-6.3) in philippine molasses according to the change of pH value. On lower or higher than the range of buffering zone, the precipitation is increased from pH 4.3 to 2.8 and from 6.3 to 8.1, it is decreased when pH value is lower or higher than the pH value range. For molasses clarifying, it had better adjust the pH of molasses solution to neutral or weak alkali range out of the alkai side of the buffering zone, with lime solution. And then, add the calcium super phosphate solution to pH value of alkali side in buffering zone, as much as the pH of clarified molasses solution can reach to middle value in buffering zone. For the equilibrium of pH value on clarifying molasses, it takes plenty of time more than 6 hours.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.233-237
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• 2008

The objective of this study was conducted to evaluate the effects of poultry litter amendments on pH and soluble reactive phosphorus (SRP) in poultry litter. Two laboratory studies were conducted for 42 d in Exp. 1 and for 10 d in Exp. 2, respectively. The poultry litter was treated with various amendments which included 4 g fly ash and 4 g $AlCl_3\;(AlCl_36H_2O)/100g$ litter in Exp. 1 and 4 g alum$(Al_2(SO_4){_3}\;14H_2O)$, 8 g alum, 8.66 g liquid alum, and 17.3 g liquid alum/100 g litter in Exp. 2; untreated litter served as controls. There were no differences in pH between control and T1(4 g fly ash) and SRP contents between T1(4 g fly ash) and T2(4 g $AlCl_3$) in Exp. 1. A significant difference in pH and SRP contents in Exp. 2 was observed among all treatments(P< 0.05). In experiment 1, T1(4 g fly ash) and T2(4 g $AlCl_3$) at 42 d decreased SRP in litter by 47.1% and 62.6% of that from litter alone, respectively. In experiment 2, T1(4 g alum), T2(8.66 g liquid alum), T3(8 g alum), and T4(17.3 g liquid alum) treatments at 10 days reduced SRP contents by up to 36.2%, 62.9%, 87.0%, and 83.9%, respectively, when compared with the controls. Decrease in SRP contents was chiefly associated with reduction in litter pH. These results indicate that use of various litter amendments to limit P solubility has potential and should be pursued as a means of reducing soluble reative phosphorus during short term.

• Journal of the Korean Ceramic Society
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• v.29 no.1
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• pp.74-82
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• 1992

Ultra-fine calcium phosphate powders were synthesized by the reaction of Ca(OH)2 suspension with various phosphoric aqueous solutions such as (NH4)2HPO4, H4P2O7 and H3PO4, and the characterization of powders was examined for each synthetic condition. When (NH4)2HPO4 and H3PO4 were used, hydroxyapatite powders with poor crystallinity were obtained. In the case of H4P2O7, amorphous calcium phosphate was obtained up to 0.3 mol/ι Ca(OH)2 suspension, but above the concentration, poor crystalline hydroxyapatite was produced. Crystalline phases of powders heat-treated at 80$0^{\circ}C$ were hydroxyapatite, $\beta$-tricalcium phosphate and $\beta$-tricalcium phosphate for the case of (NH4)2HPO4, H4P2O7 and H3PO4, respectively. SEM observation revealed that the shapes of synthesized powders were vigorously agglomerated spherical with the size below 100 nm, but TEM observation revealed that primary shapes of particles were rod for (NH4)2HPO4 and H3PO4 and were sphere for H4P2O7. There was no dependence of the concentration of Ca(OH)2 suspension. In the case that reaction temperature and pH of the suspension were raised, the inclination to the hydroxyapatite were remarkable. The amorphous calcium phosphate synthesized in this experiment contained water about 20% , and was crystallized to $\beta$-tricalcium phosphate at 69$0^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.3
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• pp.5-14
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• 2020

This study aims to survey the effect of sulphuric acid (H₂SO₄) treatment for pH adjustment with 6.5 and 7.0 regarding ammonia volatilization on chemical content change in the aerobic liquefying process of co-digesate swine manure and apple pomace. The digestates of swine manure was aerated with 0.3 ㎥ air/㎥·min for 60 days. The untreated digestate showed the increased pH and decreased contents of electrical conductivity (EC) and total nitrogen (T-N). The untreated digestate had a high concentration of NH₃ with 172.6 mg/L, but, ammonia (NH₃) concentration of H₂SO₄-treated digestate was significantly lower than that of untreated digestate. The H₂SO₄-untreated digestate for retaining aeration showed a decreased concentration of 47.2% of ammonium nitrogen. While, the H₂SO₄-treated digestate had a high concentration of ammonium nitrogen compared to the untreated digestate. Also, the H₂SO₄ treatment affected to increase the contents of nitrogen and phosphoric acid content. Therefore, the pH adjustment with H₂SO₄ might be a useful method for the decreased ammonia concentration and nitrogen maintenance in the aerobic liquefying process of swine manure digesate.

• Applied Biological Chemistry
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• v.49 no.3
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• pp.180-185
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• 2006

${\alpha}$-Galactosidase was partially purified from the culture filtrate of Debaryomyces sp. by Mannobiose-Sepharose affinity column chromatography. The galactosidase exhibited maximum activity at pH 4.0 and $60^{\circ}C$, and was stable in the pH and temperature ranges of 3 to 4.5 and 30 to $50^{\circ}C$, respectively. The enzyme was inhibited by $Hg^{2+}\;and\;Ag^{2+}$. The enzyme activity was not affected considerably by treatment with other metal compounds. The enzyme hydrolyzed melibiose to galactose and glucose, raffinose to galactose and sucrose, and $Gal^3Man_3$ ($6^3-{\alpha}$-galactosyl-1,4-mannotriose) to galactose and mannotriose. On the contrary, it could not hydrolyze $Gal^3Man_4$ ($6^3-{\alpha}$-galactosyl-1,4-mannotetraose).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.3
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• pp.309-314
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• 1999

A microporous zeolite-type tianosilicate (TS-1), new catalysis elements, was synthesized by differents of the reactant solution pH. The range of reactant solution pH has from 10.0 to 12.4 TS-1 Zeolite (ETS-10), having a large pore (8~10 ${\AA}$), was synthesized at 10.4 of pH, since TS-1 Zeolite (ETS-4), having a small pore (3~5 ${\AA}$), was synthesized at 11.5 of pH. Also the two materials simultaneously existed at the intermediate pH. Crystallization, physico chemical characteristics of synthesized TS-1 Zeolite were investigated by XRD, XRF, SEM and FT-IR techniques.