• Title/Summary/Keyword: Sulfate reduction

Search Result 362, Processing Time 0.024 seconds

Enhanced Electrogenerated Chemiluminescence of Tris (2,2'-bipyridyl) Ruthenium (II)-$S_2O_8^{2-}$ System by Sodium Dodecyl Sulfate

  • Kang, Sung-Chul;Oh, Soo-Il;Kim, Kang-Jin
    • Bulletin of the Korean Chemical Society
    • /
    • v.11 no.6
    • /
    • pp.505-508
    • /
    • 1990
  • The electrochemical reduction and electrogenerated chemiluminescence (ECL) of $Ru(bpy)_3^{2+}-S_2O_8^{2-}\;in\;CH_3CN-H_2O$ solution were studied in the presence of sodium dodecyl sulfate (SDS) as an anionic surfactant. SDS enhanced the ECL and the fluorescence intensities and lengthened the duration of ECL due to the solubilization of reactants and possibly to the stabilization of ECL intermediates in the SDS micellar environment.

An Experimental Study on the Sulfate Resistance of Fly Ash Antiwashout Underwater Concrete (플라이애시를 혼입한 수중불분리성 콘크리트의 내 황산염에 관한 실험적 연구)

  • Kwon, Joong-Hyen;Kim, Bong-Ik
    • Journal of Ocean Engineering and Technology
    • /
    • v.25 no.3
    • /
    • pp.40-46
    • /
    • 2011
  • This paper describes the effects of fly ash replacement on the sulfate resistance of antiwashout underwater concrete which was replaced cement by fly ash from 0% to 50%. and the experimental works were performed on sulfate acceleration test of 5%$Na_2SO_4$ solution to find out the variance of length and weight of specimens. The experimental result shows that the length of specimens of antiwashout underwater concrete age at 180day was highly increased compare with normal concrete by acceleration test. but the mixture which was replaced 50% of fly ash shows reduction of the expansion, weight various, compare with normal concrete specimen. accordingly by using fly ash as admixture in antiwashout underwater concrete in sea environment, it will makes more durable for the attacks of sulfate by sea water.

Problems and improvement methods of passive treatment systems for acid mine drainage in Korea

  • Ji, Sang-Woo;Ko, Ju-In;Kim, Sun-Joon
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 2003.11a
    • /
    • pp.504-510
    • /
    • 2003
  • This study has been carried out to evaluate the passive treatment systems for acid mine drainage in Korea and to suggest, if possible, the method for the improvement. 35 passive treatment systems in 27 mines have been constructed since 1996. SAPS, being the main process, was combined with more than one of processes such as anaerobic wetland, aerobic wetland, and oxidation pond for the construction of passive treatment system. Problems observed during the operation include the poor sulfate removal ratio, overflow, leakage, unusabless of the whole system, and inefficiency. The reasons of the poor sulfate removal ratio are believed that the low temperature during the winter prohibits the SRB activity and HRT for bacterial sulfate reduction is insufficient. An alternative method In Adit Sulfate Reducing System which enables to keep the temperature constant at about $15^{\circ}C$ was suggested. IASRS is the methods of placing the SAPS inside the adit, which enables the temperature around the system constant can be maintained. The experiments using the laboratory scaled model systems made up of four sections showed high efficiencies in pH control and metal removal ratios, but showed still low sulfate removal ratio of about $23\%$ also with high COD at the beginning of the operation.

  • PDF

Electrochemical Investigation of Bovine Hemoglobin at an Acetylene Black Paste Electrode in the Presence of Sodium Dodecyl Sulfate

  • Zhan, Guoqing;Li, Chunya;Luo, Dengbai
    • Bulletin of the Korean Chemical Society
    • /
    • v.28 no.10
    • /
    • pp.1720-1724
    • /
    • 2007
  • Electrochemical behaviors of bovine hemoglobin (Hb) at an acetylene black paste electrode based on the enhancement effect of sodium dodecyl sulfate (SDS) were investigated. In the optimal conditions, a very weak reduction peak was observed at an acetylene black paste electrode for hemoglobin in the absence of SDS. However, the reduction peak current increased remarkably after the addition of 4.0 × 10?4 mol L?1 SDS, suggesting that SDS exhibits obvious enhancement effect to the determination of hemoglobin. All the experimental parameters, such as pH value, concentration of SDS, accumulation time and accumulation potential were optimized for hemoglobin analysis. The proposed method possesses high sensitivity (detection limit is 3.0 × 10?9 mol L?1), wide linearity (6.0 × 10?9 to 6.0 × 10?7 mol L?1), rapid response and low cost. Finally, the method was successfully employed to determine hemoglobin in a spiked sample.

Effect of Reaction Conditions on the Preparation of Nano-sized Ni Powders inside a Nonionic Polymer

  • Kim, Tea-Wan;Kim, Dong-Hyun;Park, Hong-Chae;Yoon, Seog-Young
    • Proceedings of the Korean Powder Metallurgy Institute Conference
    • /
    • 2006.09a
    • /
    • pp.462-463
    • /
    • 2006
  • Monodispersed and nano-sized Ni powders were synthesized from aqueous nickel sulfate hexahydrate $(NiSO_4{\cdot}6H_2O)$ inside nonionic polymer network by using wet chemical reduction process. The sucrose was used as a nonionic polymer network source. The effect of reaction conditions such as the amount of sucrose and a various reaction temperature, nickel sulfate hexahydrate molarity. The influence of a nonionic polymer network on the particle size of the prepared Ni powders was characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis (PSA). The results showed that the obtained Ni powders were strong by dependent of the reaction conditions. In particular, the Ni powders prepared inside a nonionic polymer network had smooth spherical shape and narrow particle size distribution.

  • PDF

Electrochemical Studies of Viologens in Homogeneous Aqueous and Sodium Dodecyl Sulfate Micellar Solutions

  • Park Joon Woo;Ko Seung Hyeon;Park Jong-Yoon
    • Bulletin of the Korean Chemical Society
    • /
    • v.13 no.3
    • /
    • pp.259-265
    • /
    • 1992
  • Cyclic voltammetric behavior of symmetric (dimethyl, diheptyl, dioctyl, dibenzyl) and asymmetric (methyloctyl, methyldodecyl, methylbenzyl) viologens was investigated in homogeneous aqueous solution and sodium dodecyl sulfate (SDS) micellar media. In SDS-free 0.1 M NaCl solutions, the reduction potential is less negative as the chain length of alkyl substituent is longer. This is due to the stabilization of the reduced cationic radical and neutral form of viologen by adsorption on electrode surface. The adsorbed species show the "aging-effect". With the exceptions of methyldodecyl viologen and methylbenzyl viologen, the viologens show strong tendency of conproportionation reaction between viologen dications and neutral forms. In cases of methyldodecyl viologen and methylbenzyl viologen, the conproportionation reaction is kinetically disfavored, though it is thermodynamically favorable. SDS micelles dissolve the adsorbed species and the viologens exhibit two reversible redox processes in SDS micellar solutions. The reduction potentials of viologens in SDS micellar solutions depend little on the length of alkyl chain. Benzyl-substituted viologens are more easily reduced than the alkyl substituted viologens, presumably due to electron-withdrawing character of benzyl group.