• 한국물환경학회지
• /
• 제33권4호
• /
• pp.409-415
• /
• 2017

This study aims to evaluate the effect of capping materials on blocking pollutant elution from contaminated sediment to water body. Experiments were carried out under conditions in which the elution rate was intensified artificially using compost with high concentration of organic compound and nutrient salts instead of sediments. Activated carbon (AC), modified activated carbon (MAC), P. putida immobilized activated carbon (PBAC) and effective microorganisms immobilized activated carbon (EBAC) were used as capping materials. Zeolite (ZT) and two kinds of commercially available microorganisms immobilized zeolite products (ZC, ZN) were used for comparison experiment. The elution rate of organic compound, nitrogen and phosphorus were compared with that of control experiment. The experiments were conducted for 56 days. Concentrations of chemical oxygen demand, total nitrogen, and total phosphorus were measured to use the comparison of release rate of organic compound, nitrogen and phosphorus. From the experimental results, AC based materials showed better performance to block the elution of organic compound and nitrogen than ZT based materials. Although ZT based materials were more effective than AC and PBAC to block phosphorus, MAC and EBAC showed the best performance of phosphorus elution blocking among the all candidate materials. In conclusion, EBAC is considered as the most effective capping materials, because organic compound, nitrogen and phosphorus will be degraded continuously by EM in the long term.

• Journal of Plant Biology
• /
• 제17권3호
• /
• pp.127-136
• /
• 1974

The effect of potassium metabolism on the soybean leaves was studied with comparison of other elements during the successive growing period. The results were as follows; 1. The percentage of potassium content showed remarkable increase not only in the first compound leaf at a stage which was growing vigorously and producing new leaves, but also in the fifth compound leaf at a stage which was taking a active metabolism of nitrogen and carbohydrate but not producing new leaves. However, the percentage of potassium content was decreased in the second compound leaf than in the first one. Such a result could be regarded as a potassium removal from mature leaves into immature and flowing out from stoma through respiration. During the pod-development the percentage of potassium content in the soybean leaf was decreased. 2. If nitrogen, phosphorus and potassium were added excessively in the nutrient solution, the percentage of potassium content in the soybean leaf had increased. The effects of these elements showed a remakable increase in the excessive plot of nitrogen than in that of phosphorus. At early stage the redtarded effect of phosphorus on the growth of soybean could be covered by potassium, however, at late stage it could not. The growth of soybean plant was much more inhibited by potassium, compared with nitrogen and phosphorus. New leaves could not be produced in the potassium deficient soybean plant after the third compound leaf. The normal growth of soybean plant could not be observed if only one element was excessively added to the culture solution, compared with the deficiency of other two elements.

• 청정기술
• /
• 제23권4호
• /
• pp.378-387
• /
• 2017

영구적 난연성기를 함유한 에폭시 수지를 얻기 위하여, 본 연구에서는 디하이드록시를 함유한 인 화합물[10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phospha phenanthrene-10-oxide, DOPO-HQ]과 디하이드록시를 함유한 실리콘 화합물(polydimethylsiloxane, hydroxyl terminated, PDMS)를 경화하지 않은 에폭시 프리폴리머(diglycidyl ether of bisphenol A, DGEBA)와 반응시킨 다음, 경화제(4,4-diaminodiphenylmethane, DDM)를 사용하여 경화반응 시킨 에폭시 수지를 제조하였다. 제조된 에폭시 수지의 각종 특성을 적외선 분광분석기(FTIR), 시차주사열량기(DSC), 열중량 분석기(TGA), 한계산소지수(LOI)/수직 연소 시험(UL 94-V test), 인장 및 충격 시험을 이용하여 분석하였다. 그리고 사용한 인 및 실리콘 화합물의 함량이 에폭시 경화물의 열적/기계적 성질 및 난연성에 미치는 영향을 조사하였다. 인 및 실리콘 성분이 함유된 에폭시 수지의 열적 및 기계적 물성이 단순 에폭시 수지의 물성에 비교하여 크게 향상되었다는 것을 알 수 있었다. 그리고 인 및 실리콘을 함유한 모든 에폭시 수지는 29.9 ~ 31.8%의 LOI 및 V-0 수준의 UL 94-V로 난연성 기준(LOI: 30% 이상, UL 94-V: V-0)을 통과한 반면, 단순 에폭시 수지는 LOI: 21.4% 및 UL 94-V: no rating으로 난연성 기준에 크게 못 미치는 것을 알 수 있었다.

• 한국응용과학기술학회지
• /
• 제20권4호
• /
• pp.275-282
• /
• 2003

Aqueous polyurethane dispersion was synthesized using phosphorus compound which received significant attention for the replacement of halogenated flame retardants. In this study, polyols which have phosphorus moity in their structural unit were synthesized by two-step polycondensation reaction using dimethyl phenylphosphonate, ethylene glycols. adipic acid, and 1,4-butanediol. In the next step, polyurethane dispersion was prepared using these polyols, isophorone diisocyanate with dimethyl propionic acid. The particle size of polyurethane latex was reduced from 347 nm to 240 nm with increasing DMPA content. It was observed that the LOI values of prepared coatings increased from 27% to 35% with increasing phosphorus content.

• 한국환경생물학회:학술대회논문집
• /
• 한국환경생물학회 2002년도 춘계공동학술대회 및 심포지움 초록집
• /
• pp.46-46
• /
• 2002

• 한국응용과학기술학회지
• /
• 제23권2호
• /
• pp.99-109
• /
• 2006

In order to obtain the maximum flame retardancy as well as the minimum deterioration of physical properties of PU flame-retardant coatings, chlorine and phosphorus functional groups were introduced into the pre-polymer of modified polyesters. In the first step, the tetramethylene bis(orthophosphate) (TBOP) and neohexanediol dichloroacetate (DCA-adduct) intermediates were synthesized. In the second step, 1,4-butanediol and adipic acid monomers were polymerized with the two kinds of intermediates to obtain copolymers. The modified polyesters containing chlorine and phosphorus (ATBA-10C, -20C, and -30C) were synthesized by adjusting that the content of phosphorus compound was fixed as 2wt% and the contents of chlorine compound (dichloroacetic acid) were varied as 10, 20, and 30wt%. Average molecular weight and polydispersity index of the preparation of ATBAs were decreased with increasing DCA content because of the increase in hydroxyl group that retards reaction.

• 한국환경과학회지
• /
• 제28권10호
• /
• pp.851-861
• /
• 2019

In this study, we performed a sediment elution experiment to evaluate water quality in terms of phosphorus, as influenced by the dissolved oxygen consumed by sediments. Three separate model column treatments, namely, raw, calcined, and sonicated oyster shell powders, were used in this experiment. Essential phosphorus fractions were examined to verify their roles in nutrient release from sediment based on correlation analyses. When treated with calcined or sonicated oyster shell powder, the sediment-water interface became "less anaerobic," thereby producing conditions conducive to partial oxidation and activities of aerobic bacteria. Sediment Oxygen Demand (SOD) was found to be closely correlated with the growth of algae, which confirmed an intermittent input of organic biomass at the sediment surface. SOD was positively correlated with exchangeable and loosely adsorbed phosphorus and organic phosphorus, owing to the accumulation of unbound algal biomass-derived phosphates in sediment, whereas it was negatively correlated with ferric iron-bound phosphorus or calcium fluorapatite-bound phosphorus, which were present in the form of "insoluble" complexes, thereby facilitating the free migration of sulfate-reducing bacteria or limiting the release from complexes, depending on applied local conditions. PCR-denaturing gradient gel electrophoresis revealed that iron-reducing bacteria were the dominant species in control and non-calcined oyster shell columns, whereas certain sulfur-oxidizing bacteria were identified in the column treated with calcined oyster powder.

• Macromolecular Research
• /
• 제16권7호
• /
• pp.620-625
• /
• 2008

A novel nitrogen-phosphorus compound, diphenyl piperazine-1,4-diylbis(methylphosphinate)(DPPMP) was synthesized via a two step reaction and its flame retarding efficiency as a single component additive was investigated. The success of synthesis was confirmed by FTIR and $^1H$ and $^{31}P$ NMR analysis. The product was mixed with polycarbonate (PC), poly(butylene terephtalate) (PBT), ethylene-vinyl-acetate copolymer (EVA), and acrylonitrile-butadiene-styrene copolymer (ABS). The flame-retarding efficiency was evaluated using the limiting oxygen index (LOI) and the UL-94 vertical test methods. The addition of DPPMP enhanced the flame retardancy of the polymers and the V-0 ratings were obtained for the polymers examined in this study at a loading of 7-30 wt%. The gas-phase flame retardancy mode of action was suggested for this material from the thermogrametry experiment results.

• 한국토양비료학회지
• /
• 제10권2호
• /
• pp.85-92
• /
• 1977

인산감수성(燐酸感受性)이 다른 9개대두재배종(個大豆栽培種) Lee, Hill, Harosoy, Clark-63, Chippewa 및 R56-49을 서로 다른 질소원(窒素源)으로 수경재배(水耕栽培)하여 엽중유리당(葉中遊離糖)과 유기산(有機酸)을 gas chronatograph로 조사(調査)하여 미동정(未同定)의 X, Y peak와 Sucrose peak가 주(主) peak로 나타났다. X 화합물(化合物)은 NO3-N 급여(給與)경우 흔적으로 나타난데 반하여 NH4-N나 urea 급여(給與)경우에 다량(多量)나타났다. Y 화합물(化合物)을 Urea 급여(給與)경우 감소하는 경향이었다. Sucrose는 NH4-N 급여(給與)에서 흔적으로 나타나고 Urea에서 NO3-N에서보다 높았다. X 화합물(化合物)은 erythrose에서 유래(由來)한 4 탄소(炭素) 산성당(酸性糖)이거나 Purine이나 Pyrimidine에서 유래(由來)한 환상화합물(環狀化合物)로 Y 화합물(化合物)은 glycolysis path에서 유래(由來)한 6 탄당(炭糖)으로 추정(推定)되었다. Y/X 치(値)는 인산감수성(燐酸感受性)의 좋은 지표(指標)가 되므로(역관계(逆關係)) 이 두 화합물(化合物)은 ammonia 독작용(毒作用) 및 인산감수성(燐酸感受性) 기작(機作)에 관여(關與)하는 요인화합물(要因化合物)로 보였다.

• Journal of Microbiology and Biotechnology
• /
• 제15권6호
• /
• pp.1159-1163
• /
• 2005

The production of hydrogen by Chlamydomonas reinhardtii UTEX 90, a marine green alga, was performed under dark fermentation. The effects of initial nitrogen and phosphorus concentration on the cell growth and the production of hydrogen and organic substances were investigated. In the growth stage, the maximum dry cell weight (DCW) was 3 g/l when the initial ammonium concentration was 15 mM. In the dark fermentation, the maximum hydrogen production was $3.5\;{\mu}mol/\;mg$ DCW when the initial nitrogen concentration was 7.5 mM. The nitrogen concentration had a greater effect on organic compound and hydrogen production than the phosphorus concentration during the dark fermentation. An investigation of the duration of dark fermentation showed that, at least until three days, dark fermentation should be prolonged for maximum hydrogen production.