• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.560-567
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• 2020

In this study, we investigated that the effect of alkali metals [Na(Sodium) and K(Potassium)], known as representative deactivating substances among exhaust gases of various industrial processes, on the NH₃-SCR (selective catalytic reduction) reaction of V/W/TiO₂ catalysts. NO, NH₃-TPD (temperature programmed desorption), DRIFT (diffuse reflectance infrared fourier transform spectroscopy analysis), and H₂-TPR analysis were performed to determine the cause of the decrease in activity. As a result, each alkali metal acts as a catalyst poisoning, reducing the amount of NH₃ adsorption, and Na and K reduce the SCR reaction by reducing the L and B acid points that contribute to the reaction activity of the catalyst. Through the H₂-TPR analysis, the alkali metal is considered to be the cause of the decrease in activity because the reduction temperature rises to a high temperature by affecting the reduction temperature of V-O-V (bridge oxygen bond) and V=O (terminal bond).

• Preventive Nutrition and Food Science
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• v.7 no.3
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• pp.317-319
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• 2002

Exo-polygalacturonase (EPG) from Rhizopus sp. was applied to the extraction of alginic acid from sea mustard to increase extraction yield. EPG digestion was examined under distinct conditions within temperatures from $25^{\circ}C$ to 5$0^{\circ}C$, pH 5 to 9, and treatment times from 0 to 36 hr. The optimal conditions fur alginic acid extraction with EPG were: pH 7.0 at 3$0^{\circ}C$ for 24 hrs. The EPG hot water extraction yield was 3.4 times higher yield than hot water extraction alone. Using EPG to extract alginic acid from sea mustard should be considered a viable alternative to conventional extraction, with the advantage of reducing hazardous wastes such as strong acid and alkali solutions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.747-752
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• 2004

Alginates were extracted from the Laminaria religiosa, Undaria pinnatifida, and Hizikia fusiforme by using four different extraction methods and compared the yields of alginate. Acid-alkali soluble alginate (AASA) extraction method from Undaria pinnatifida resulted in the best yield of alginate among the seaweeds. The optimal condition for extracting alginate from Laminaria religiosa was 0.4 N H$_2$SO$_4$ and 3% NaCO$_3$ concentrations at the AASA extraction method. The alginate yields of hot water extractable material (HWEM) water soluble alginate (WSA), alkali soluble alginate (ASA) and AASA in Hizikia fusiforme were 18.6, 4.7, 22.5 and 26.5%, respectively. The alginates manufactured by the WSA extraction method showed more bright color than those of the ASA and AASA extraction methods. The alginate prepared by the ASA extraction method from Hizikia fusiforme showed the higher viscosity than that of the ASA extraction method. The molecular weight of the alginate from Hizikia fusiforme was 33.3 kDa to 121.6 kDa depending on the extraction method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.5
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• pp.75-84
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• 2016

This paper presents an investigation of the mechanical properties on non-sintered cement pastes immersed in sea waters at three different temperatures. The non-sintered cement pastes were synthesized using blended binder(Class F fly ash; FA and ground granulated blast furnace slag; GGBFS) and alkali activator(sodium hydroxide and sodium silicate). Binders were prepared by mixing the FA and GGBFS in different blend weight ratios of 6:4, 7:3 and 8:2. The alkali activators were used 5wt% of blended binder, respectively. Calcium carbonate was used as an chemical additive. The compressive strength, bulk density and absorption of alkali-activated FA-GGBFS blends pastes were measured at 3 and 28 days after immersed in sea waters at three different temperatures($5^{\circ}C$, $15^{\circ}C$ and $25^{\circ}C$). The XRD and SEM tests of the pastes were conducted at 28 days. Water-soluble chloride(free chloride) and acid-soluble chloride(total chloride) contents in the pastes were also measured after 28 days immersion in sea water. The experimental results showed that increasing the content of FA in alkali-activated FA-GGBFS blends pastes immersed in sea water increases the absorption, water-soluble chloride content and acid-soluble chloride content, and reduces the compressive strength and bulk density. And it was found that there was a variation of strength change for the alkali-activated FA-GGBFS blends pastes immersed in sea waters at three different temperatures that depends on the blending ratio of FA and GGBFS.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.6
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• pp.238-242
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• 2016

The effect of the alkali, alkali earth metal elements on selective catalytic reduction(SCR) catalyst deactivation behavior were investigated in terms of microstructure, surface area, pore volume and De-NOx test. Poisoned SCR catalyst were manufactured by injection of $K_2CO_3$, $Na_2CO_3$, $Ca(CH_3COO)_2{\cdot}H_2O$, $C_4H_6MgO_4{\cdot}4H_2O$, $H_3PO_4$ solutions in the new SCR catalyst at $350^{\circ}C$ for 6 hours. New and poisoned catalysts surface were similar. But specific surface area, pore volume decrease from Na, Mg, K, Ca, P compared to new SCR catalyst. Especially, Na poisoned catalyst surface area and pore size extremely decreased by $10.20m^2/g$, $0.061cm^2/g$. De-NOx test results of new and poisoned catalysts at $150{\sim}450^{\circ}C$ indicated that alkali metal (K, Na) poisoned SCR catalysts have the lowest De-NOx efficiency, alkali earth metal poisoned SCR catalysts (Ca, Mg) De-NOx efficiency are higher than alkali metal poisoned SCR catalysts. P poisoned SCR catalyst De-NOx efficiency is similar new SCR catalyst. It were considered that physical deactivation of SCR catalyst was affected by SCR catalyst surface area and pore volume change.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1430-1433
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• 2004

A study was conducted to determine the effect of different alkali treatments on changes in chemical composition and on degradability of bagasse and rice straw. This study divided into 2 experiments, the first with bagasse and the second with rice straw. Each experiment comprised 9 treatments which included: untreated control; 3% NaOH; 6% NaOH; 3% urea; 6% urea; 3% NaOH/3% urea; 3% NaOH/6% urea; 6% NaOH/3% urea; 6% NaOH/6% urea. In both experiments, crude protein contents were increased from 2.0 to 12.5 units for bagasse and 3.1 to 13.7 units for rice straw by urea treatments. Ash contents of the treated bagasse and rice straw were increased over the untreated control (1.5-9.7 units for bagasse; 4.2-8.8 units for rice straw). The effects on ether extract, crude fiber, neutral detergent fiber and acid detergent fiber of the treated bagasse and rice straw were variable. Nylon bag degradability of dry matter and crude fiber were increased by treatments applying NaOH and NaOH plus urea but not urea alone. In contrast, the egradability of neutral detergent fiber and acid detergent fiber were reduced compared with the untreated control. From these degradability studies, it can be concluded that the most efficient treatments of bagasse were those treatments with 6% NaOH, followed by treatments with 6% NaOH plus 3% or 6% urea and 3% NaOH plus 3% or 6% urea, respectively. However, when comparison was made on the cost of chemical used to treat the agricultural by-products, particularly in case of rice straw, 3-6% urea would be appropriate.

• Analytical Science and Technology
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• v.24 no.3
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• pp.200-211
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• 2011

In this study, 13 compounds including four volatile fatty acids (VFA) and nine volatile organic compounds (VOC) were analyzed by cryogenic trapping-thermal desorption technique. In order to evaluate the analytical method for VFA, calibration experiments were performed using five different sorbent materials. When the calibration results are compared between different sorbents, sampling tube filled with Carbopack X showed the highest response factor (RF) for both VFA and VOC. To validate this new analytical method for VFA using cryogenic trapping-thermal desorption technique, this method was compared with alkali absorption method recommended by the odor prevention law of the Korea Ministry of Environment (KMOE). For this purpose, unknown samples were analyzed by two different methods, i.e., cryogenic trapping-thermal desorption (TD) and alkali absorption with solid phase microextraction (SPME). When the results of two different methods were compared, ratios of concentrations determined by the two analytical methods (TD/SPME) was found as 0.46 (valeric acid) ~ 0.71 (isovaleric acid). Therefore, additional study is required to properly establish and find stable analytical conditions for VFA analysis. Furthermore, comparison between two different methods should be made with more reliable calibration approaches.

• Preventive Nutrition and Food Science
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• v.7 no.4
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• pp.451-453
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• 2002

Alkali treatment following acidic hydrolysis (ATAH) of defatted soybean is currently used to reduce the level of 3-chloropropane-1,2-diol (3-MCPD), a known carcinogen, in commercial Korean soy sauce. 3-MCPD concentrations in commercial soy sauces made by ATAH were compared with those made only by acidic hydrolysis, and products that combine soy sauce made by acid hydrolysis (followed by alkalinization) and enzymatic methods. The four soy sauces made by ATAH had lower 3-MCPD concentrations (below 0.078 ppm) than 4 commercial products (0.147∼0.481 ppm) made only by acidic hydrolysis. On the other hand, 3-MCPD concentrations in 4 commercial products made by combining soy sauces made enzymatically with that made from acid (with alkali treatment)-hydrolyzed soybean protein in varying ratios were in a range of 0.016∼0.053 ppm. The 3-MCPD concentrations in commercial Korean soy sauces, with the exception of 2 of the soy sauces made only by acidic hydrolysis, were lower than allowable limit of 0.3 ppm in Korea. These results demonstrated that currently produced commercial soy sauces on the Korean market hate toxicologically save 3-MCPD concentrations. It is also provides evidence that ATAH is an effective process for reducing 3-MCPD concentrations in commercial soy sauce.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.92-97
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• 2011

The effect of Group I alkali acetate promoters on vinyl acetate (VA) synthesis was evaluated. Catalyst product selectivity and ethylene conversion are compared to the unpromoted catalyst in the fixed-bed reactor with oxidation reaction of ethylene and acetic acid in gaseous phase over Pd-Au/$SiO_2$ catalyst. It was found that: a) the promoters were stabilized on the catalyst surface, b) common effect for the alkali promoted Pd-Au catalysts increaseed in product selectivity and ethylene conversion compared to unpromoted catalyst (these effects increase from top to the bottom of Group I). These promoting effect is due to the common-ion effect of acetate, present in the reaction, resulting in an increase in the activity of the catalyst. In addition a complementary theory for the effect of Au in the structure of the catalyst is proposed the imposition of distribution of palladium particles through decreasing the particle's diameter.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.131-143
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• 2018

Phosphorus (P) is a limited, essential, and irreplaceable nutrient for the biological activity of all the living organisms. Sewage sludge ash (SSA) is one of the most important secondary P resources due to its high P content. The SSA has been intensively investigated to recover P by wet chemicals (acid or alkali). Even though $H_2SO_4$ was mainly used to extract P because of its low cost and accessibility, the formation of $CaSO_4$ (gypsum) hinders its use. Heavy metals in the SSA also cause a significant problem in P recovery since fertilizer needs to meet government standards for human health. Therefore, P recovery process with selective heavy metal removal needs to be developed. In this paper some of the most advanced P recovery processes have been introduced and discussed their technical characteristics. The results showed that further research is needed to identify the chemical mechanisms of P transformation in the recovery process and to increase P recovery efficiency and the yields.