• 제목/요약/키워드: Excess ammonium

검색결과 49건 처리시간 0.031초

제주시 도심지역에서 여름과 겨울의 PM2.5 이온조성 특성 (Ionic Compositions of PM2.5 during Summer and Winter in the Downtown Area of Jeju City in Jeju Island)

  • 이기호;허철구
    • 한국환경과학회지
    • /
    • 제26권4호
    • /
    • pp.447-456
    • /
    • 2017
  • Chemical properties of aerosols were investigated by analyzing the inorganic water-soluble content in $PM_{2.5}$ collected in the downtown area of Jeju City in Jeju Island. Due to an increase in both the number of visiting tourists and the size of local population, the number of cars in this area is increasing, causing an increase in $PM_{2.5}$. Eight $PM_{2.5}$-bound major inorganic ions were analyzed during the summer and winter periods. The water-soluble inorganic component represents a significant fraction of $PM_{2.5}$. In particular, secondary inorganic aerosols contribute 36.2% and 47.5% of $PM_{2.5}$ mass in summer and winter, respectively. Nitrate concentrations increase for $[NH_4{^+}]/[SO_4{^{2-}}]$>1.5, and excess ammonium, which is necessary for ammonium nitrate formation, is linearly correlated with nitrate. These results are clearly observed during the winter because conditions are more conducive to the formation of ammonium nitrate. A significant negative correlation between Nitrogen Oxidation Ratio (NOR) and temperature was observed. The obtained results can be useful for a better understanding of the aerosol dynamics in the downtown area in Jeju City.

Ammonium Caprylate 와 Ammonium Caprate 溶液의 表面張力 (The Surface Tension of Solutions of Ammonium Caprylate and Ammonium Caprate)

  • 한만운;이종만
    • 대한화학회지
    • /
    • 제7권4호
    • /
    • pp.277-279
    • /
    • 1963
  • The surface tension of solutions of synthesized ammonium caprylate and ammonium caprate was measured by the ring method. The changes with of surface tension of solution of ammonium caprylate showed evidently that the salt had the critical micelle concentration(c.m.c.) at $30^{\circ}C$. The c.m.c. values of above two salts were determined from the change of surface tension of solution with concentration at various temperatures. The temperature dependence of the c.m.c. and the influence of addition of excess ammonia on the c.m.c. were also investigated.

  • PDF

제주시 도심지역에서 여름철과 겨울철의 미세먼지 중 수용성 이온 조성 (Ionic Compositions of Fine Particulate Matter during Summer and Winter in the Downtown Area of Jejusi City in Jeju Island)

  • 이기호;김수미;허철구
    • 한국환경과학회지
    • /
    • 제26권5호
    • /
    • pp.591-600
    • /
    • 2017
  • This study was carried out to elucidate the chemical compositions of water-soluble inorganic ions in $PM_{10}$ and $PM_{2.5}$ aerosols collected during summer and winter in downtown Jejusi city. The ratios of $NO_3^-$ to the total mass of ionic species in $PM_{10}$ and $PM_{2.5}$ aerosols largely increase in winter compared to summer, while $SO_4^{2-}$ ratios in both aerosols appear to follow the opposite trend. Moreover, concentrations of $Na^+$, $Mg^{2+}$, $Ca^{2+}$ and $Cl^-$ in $PM_{10}$ and $PM_{2.5-10}$ aerosols are higher in winter than in summer. The nitrate concentrations in $PM_{10}$ and $PM_{2.5}$ aerosols increase with an identical increase in excess ammonium during winter, however, nitrate formation during summer is not important owing to ammonium-poor conditions.

팔당호로의 질소와 황성분 침적 측정 (Measurement of Nitrogen and Sulfur Deposition to Lake Paldang)

  • 김영성;진현철
    • 한국대기환경학회지
    • /
    • 제21권1호
    • /
    • pp.39-48
    • /
    • 2005
  • Nitrogen and sulfur deposition was measured on Lake Pal dang from March 2002 to October 2003. Wet and dry depositions were separately measured using wet- and dry-only samplers, respectively. In order to measure the dry deposition to the water body, a dry deposition sampler composed of three pans filled with pure water, called the deposition water, was used. Since ammonium was generally in excess in ambient air, more than half of ammonium was present in the gaseous form. Ammonium concentration was also generally higher than the sum of major anion concentrations in the deposition water because gaseous species were much easily deposited than the species in fine particles. Nevertheless, the contribution of gaseous ammonia to the deposition of ammonium was not high as well as that of particulate ammonium while the contribution of gaseous nitric acid was much higher than that of particulate nitrate. Annual wet deposition fluxes of nitrogen and sulfur were five and six times higher than their dry deposition fluxes, respectively. Except for ammonium, the dry deposition flux estimated in the present work was a half of the previous results. This was mainly caused by much smaller dry deposition velocities over the water than over the ground.

Methylobacterium organophilum에 의한 메탄올로부터 메틸란의 생산에 대한 암모니아 이온의 영향 (Effect of Ammonium Ion on the Production of a Polysaccharide, Methylan from Methanol by Mentylobacterium organophilum)

  • 오덕근;임현수김정회
    • KSBB Journal
    • /
    • 제10권2호
    • /
    • pp.170-175
    • /
    • 1995
  • Methylobacterium organophilum을 이용하여 메탄 올로부터 고점성 다당류의 생산에 대한 질소원 이용의 통력학척 분석을 유가식 배양에서 수행하였다. 발효중 세포는 배지 중에 첨가된 질소원이 고갈된 후에도 계속 성장하였고, 에틸란은 질소원 고갈조건 하에서만 생성되였다 세포 성장은 배양초기에 첨가 한 질소원인 암모니아의 농도에 비례적으로 이루어 졌으나, 에릴란 생산은 첨가한 암모니아 농도가 $0.75g/\ell$ 이상에서는 오히려 현저하게 감소하였다. 초기 암모니아 농도가 높아질수록, 비세포중식 속도, 비산물생성 속도, 비기질소비 속도가 감소하였다. 높 은 암모니아 농도의 발효 속도들에 대한 저해작용을 감소시키기 위해, 질소원을 일정농도(암모니아 농도=$0.15g/\ell$) 이하로 유지시키면서 공급하는 유가식 배양법으로 메틸란의 농도를 $12.5g/\ell$ 까지 증가시킬 수있었다.

  • PDF

The Equilibrium Model of MoO$_3$ Containing Phases Supported in Silica

  • Lee, Do-Hyun;Ha, Jin-Wook
    • 한국산학기술학회:학술대회논문집
    • /
    • 한국산학기술학회 2001년도 춘계학술대회 발표논문집
    • /
    • pp.287-289
    • /
    • 2001
  • The morphology of silica supported MoO$_3$ catalysts, which was prepared by impregnation of ammonium heptamolybdate with various weight loadings up to 35 wt%, was studied using x-ray diffraction. In addition to the orthorhombic phase, the behavior of the rarely studied hexagonal phase was characterized. For high loading catalysts, excess ammonium ions present in the monoclinic and triclinic precursors are capable of occupying interstitial sites of microcrystalline MoO$_3$ during moderate temperature calcinations and in doing so enhance the MoO$_3$-SiO$_2$ interaction. This results in a "well dispersed" morphology at high loadings. Sintering at high temperature is due to loss of ammonium from the oxide framework. Ammonia reimpregnation, which leads back to the well dispersed hexagonal phase, may offer a simple regeneration process for spent Mo containing catalysts.

Highly Fluorescing Solid DNA-Cationic Polyelectrolyte Complexes Prepared from a Natural DNA and a Poly(fluorenevinylene-alt-phenylene) Bearing Quaternary Ammonium Pendants

  • Yu, Young-Jun;Kwon, Young-Wan;Kim, Kyu-Nam;Do, Eui-Doo;Choi, Dong-Hoon;Jin, Jung-Il;Shin, Hee-Won;Kim, Yong-Rok;Kang, Ik-Joong;Mikroyannidis, John A.
    • Macromolecular Research
    • /
    • 제17권4호
    • /
    • pp.245-249
    • /
    • 2009
  • A fluorescing, copolymer(Q)-bearing, quaternary ammonium pendant was mixed with excess natural salmon sperm DNA with a molecular weight of $1.3{\times}10^6$(2,000 base pairs) to afford highly fluorescing, complex mixtures. The fluorescence life-time of the polymer Q was greatly increased when mixed with DNA: for the mixture of Q:DNA=1:750 the fast and slow decay lifetimes increased from ca. 10 to 100 ps and from 20 ps to ca. 1 ns, respectively. The enhanced fluorescence of the mixtures was ascribed to efficient compartmentalization and reduced conformational relaxation of the polymer Q by complexation with excess DNA.

Ammonium Excess Promotes Proline Synthesis but Inhibits Glutathione Synthesis in Oilseed Rape (Brassica napus L.)

  • Hyunjae Lee;Seon-Hye Baek;Tae-Hwan Kim
    • 한국초지조사료학회지
    • /
    • 제43권2호
    • /
    • pp.109-115
    • /
    • 2023
  • Ammonium (NH4+) serves as a nitrogen source, but its elevated levels can hinder plant growth and production. Excess NH4+ with α-ketoglutarate is assimilated into glutamate, a precursor of proline and glutathione (GSH). This study aimed to investigate the effects of excessive NH4+ on the regulation of proline and GSH synthesis. Detached leaves from oilseed rape (Brassica napus L.) were fed with 0, 50, 100, 500, and 1000 mM NH4Cl for 16 h. As the NH4+ concentrations increased, the leaves exhibited progressive wilting and yellowing. Furthermore, total carotenoid and chlorophyll concentrations declined in response to all NH4+ treatments, with the lowest levels observed in 1000 mM NH4+ treatment. Hydrogen peroxide (H2O2) concentration showed a minor increase at low NH4+ concentration (50 and 100 mM) treatments but a significant increase at high NH4+ (500 and 1000 mM), which was consistent with the localization of H2O2. Amino acid concentrations increased with increasing in NH4+ concentration, while the protein concentration displayed the opposite trend. Proline and cysteine concentrations exhibited a gradual increase in response to increasing NH4+ concentrations. However, GSH concentrations rose only in the 50 mM NH4+ treatment and decreased in the 500 and 1000 mM NH4+ treatments. These results indicate that excessive NH4+ is primarily assimilated into proline, while GSH synthesis is adversely affected.

생물막을 이용한 상수 원수에서의 암모니아 제거 특성 (Ammonia Removal Characteristics of Biolfilm Reactor)

  • 신항식;임경호;이상민
    • 상하수도학회지
    • /
    • 제10권1호
    • /
    • pp.78-84
    • /
    • 1996
  • The presence of ammonia, usually in the form of ammonium ion ($NH_4{^+}$), can enhance bacterial growth m the distribution system and make the production of drinking water more costly if ammonium must be removed to ensure good disinfection. Removal of ammonia by biological oxidation could be economical which prevents excess chlorine dosage In this research, effects of hydraulic retention time (HRT) and media type on the ammonia removal efficiencies of submerged biofilm reactor were investigated. The biofilm reactors combined the characteristics of high biological solids capture efficiency and good hydraulic control. The results indicate that biofilms can remove over 77 percent of the ammonia with HRT of longer than 2 hr even at low temperature ranging from 14.6 to $16.6^{\circ}C$. The HRT has a significant effect on nitrification. The overall nitrification and efficiency of ammonia removal increase with increasing HRT. It has also been observed that when the fibrous media was used, the ammonia removal, nitrification rate and endurance to shock improved.

  • PDF

Determination of Chromium(VI) by Differential-Pulse Polarography with a Sodium Borate Supporting Electrolyte

  • Hong, Tae-kee;Czae, Myung-Zoon
    • Bulletin of the Korean Chemical Society
    • /
    • 제9권2호
    • /
    • pp.77-80
    • /
    • 1988
  • A suituable choice of supporting electrolyte medium for trace level determinations of chromium(VI) by differential pulse polarography is described. A comparative study suggests that sodium borate buffer is superior to ammonium acetate, ammonium tartrate, and especially to NaF which was recently known to be one of the most proper medium for the purpose. With 0.01 M borate, the best combination of high sensitivity, well-defined base line, and freedom from common interferents was attained. With $5.0{\times}10^{-7}$M Cr(VI), tenfold excesses of Cu(II) and Fe(III), and a five hundred-fold excess of $Cl^-$ do not change the peak current by more than about 1%. And the detection limit was $5.0{\times}10^{-8}$M Cr(VI).