• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.243-248
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• 1996

To find out the oxidation process of potential acid sulfate soil(PASS) along with time. the PASS were treated with lime and ammonia water to adjust soil pH in laboratory column condition. pH range of PASS showed 6.5 to 7.5. however, complete oxidized PASS by $H_2O_2$ showed 2.1 to 2.5. After pilling the PASS under the natural condition. oxidation occured slowly from surface of the pilled soil. The oxidation of PASS proceeded slowly when the soil was in submerged condition. but quickly in dried condition. The content of sulfide-sulfur in PASS sharply decreased after exposing to the air and the decreasing rate was greater in dried than in submerged condition. The content of sulfate-sulfur continuously decreased in submerged condition. but increased in dried condition. Contents of $Fe^{+{+}}$ and $Al^{+{+}}$ in PASS were generally increased with time and the increasing rate was greater in submerged than in dried condition. Liming to PASS was slowly acting to pH change and ammonia water caused fast pH change within a short period of time. The contents of sulfate-sulfur and exchangeable aluminum in drainage water decreased with time and the contents of sulfide-sulfur and ferrous iron were increased.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.2069-2071
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.483-484
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• 2007

• Food Science of Animal Resources
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• v.34 no.5
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• pp.638-646
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• 2014

The effects of two levels (1.4 vs 2.8%) of fresh garlic on lipid oxidation and microbial growth in pork patties were evaluated. Hunter color (L, a, b), pH, thiobarbituric acid reactive substances (TBARS), oxidative volatile compounds, total bacteria and Enterobacteriaceae in the pork patties with or without fresh garlic were measured during storage at $4^{\circ}C$. Addition of fresh garlic decreased redness (a), while increased pH and yellowness (b) values of the fresh pork patties were observed, regardless of the levels added. The TBARS values of the pork patties were increased with the addition of fresh garlic (p<0.05). Similar results were observed in oxidative volatile compounds. A total of 13 volatile compounds were detected in the patties (5 sulfur-containing compounds, including allyl mercaptan, allyl methyl sulfide, diallyl sulfide, methyl-(E)-propenyl-disulfide, and diallyl disulfide, and the 8 other oxidative compounds, including 1-pentanol, hexanal, 1-hexanol, heptanal, (E)-2-heptenal, 1-octen-3-ol, (E)-2-octenal and nonanal). Fresh garlic accelerated development of oxidative products in the pork patties, especially hexanal and the total oxidative volatile compounds. However, the addition of 1.4 and 2.8% of fresh garlic inhibited the growth of total bacteria and Enterobacteriaceae, indicating low total bacterial counts and Enterobacteriaceae than the controls.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.320-324
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• 2007

The removal of hydrogen sulfide ($H_2S$) from aqueous media was investigated using Thiobacillus novellas cells immobilized on a $SiO_2$ carrier (biosand). The optimal growth conditions for the bacterial strain were $30^{\circ}C$ and initial pH of 7.0. The main product of hydrogen sulfide oxidation by T. novellus was identified as the sulfate ion. A removal efficiency of 98% was maintained in the three-phase fluidized-bed reactor, whereas the efficiency was reduced to 90% for the two-phase fluidized-bed reactor and 68% for the two-phase reactor without cells. The maximum gas removal capacity for the system was 254 g $H_2S/m^3/h$ when the inlet $H_2S$ loading was $300g/m^3/h(1,500ppm)$. Stable operation of the immobilized reactor was possible for 20 days with the inlet $H_2S$ concentration held to 1,100 ppm. The fluidized bed bioreactor appeared to be an effective means for controlling hydrogen sulfide emissions.

• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.155-162
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• 2012

We observed characteristic oxidation and dissolution phenomena induced by dissolved oxygen for mackinawite that is produced via sulfate-reducing bacteria (SRB) living in anaerobic environments such as soils and groundwater. We tried to recognize the role of the sulfide minerals that usually coexist with some stabilized radionuclides (e.g., reduced uranium), which can be reoxidized and redissolved by an oxygen-rich groundwater invaded into a contaminated area. The mackinawite produced by 'Desulfovibrio desulfuricans', a sulfate-reducing bacterium, was conducted to be dissolved for 2 weeks by some oxidants such as 'hydrogen peroxide' and 'sodium nitrite'. Although mineralogical oxidation and dissolution characteristics were different from each other according to the oxidants, the initially oxidized solution was early stabilized through the oxygen consumption by ${\mu}m$-sized sulfide particles and the resultant increase of sulfate in solution. From these results, we can anticipate that the large amount of sulfide minerals generated by SRB can not only repress the anoxic environment to be disturbed by the consumption of oxygen in groundwater, but also contribute to stabilize the reduced/precipitated radionuclides as a buffer material for a long time.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.534-544
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• 2014

The effects of microbial iron reduction and oxidation on the immobilization and mobilization of copper were investigated in a high concentration of sulfate with synthesized Fe(III) minerals and red earth soils rich in amorphous Fe (hydr)oxides. Batch microcosm experiments showed that red earth soil inoculated with subsurface sediments had a faster Fe(III) bioreduction rate than pure amorphous Fe(III) minerals and resulted in quicker immobilization of Cu in the aqueous fraction. Coinciding with the decrease of aqueous Cu, $SO_4{^{2-}}$ in the inoculated red earth soil decreased acutely after incubation. The shift in the microbial community composite in the inoculated soil was analyzed through denaturing gradient gel electrophoresis. Results revealed the potential cooperative effect of microbial Fe(III) reduction and sulfate reduction on copper immobilization. After exposure to air for 144 h, more than 50% of the immobilized Cu was remobilized from the anaerobic matrices; aqueous sulfate increased significantly. Sequential extraction analysis demonstrated that the organic matter/sulfide-bound Cu increased by 52% after anaerobic incubation relative to the abiotic treatment but decreased by 32% after oxidation, indicating the generation and oxidation of Cu-sulfide coprecipitates in the inoculated red earth soil. These findings suggest that the immobilization of copper could be enhanced by mediating microbial Fe(III) reduction with sulfate reduction under anaerobic conditions. The findings have an important implication for bioremediation in Cu-contaminated and Fe-rich soils, especially in acid-mine-drainage-affected sites.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.177-185
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• 1996

The optimum conditions for the removal of hydrogen sulfide by Fe-EDTA complex in the bubble column reactor were investigated. As the concentrations of the complex increased, the conversion rate of hydrogen sulfide increased, while Fe concentration and pH were stably decreased and the amount of elemental sulfur produced was also increased. Hydrogen sulfide was removed efficiently when the concentration of Fe-EDTA complex was maintained more than 0.05M. pH acts as an important factor for the stability of complex in the oxidation of hydrogen sulfide and optimum pH range was 8.5~9.5. As the molar ratio of EDTA : Fe was increased, the conversion rate of hydrogen sulfide became stable. However, the rate was decreased due to the precipitation of FeS when the concentration of EDTA was decreased. As the concentration of EDTA increased, the conversion rate of hydrogen sulfide increased due to the high stability of Fe-EDTA complex.

• Clean Technology
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• v.20 no.4
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• pp.367-374
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• 2014

Several experiments have been done to investigate the removal of hydrogen sulfide ($H_2S$) synthetic gas from biogas streams by means of chemical absorption and chemical reaction with 0.1-1 M Fe/EDTA solution. The roles of Fe/EDTA were studied to enhance the removal efficiency of hydrogen sulfide because of oxidizing by chelate. The motivation of this investigation is first to explore the feasibility of enhancing the toxic gas treatment in the biogas facility. The biogas purification strategy affords many advantages. For instance, the process can be performed under mild environmental conditions and at low temperature, and it removes hydrogen sulfide selectively. The end product of separation is elemental sulfur, which is a stable material that can be easily disposed with minor potential for further pollution. As the Fe-EDTA concentration increased, the conversion rate of hydrogen sulfide increased because of the high stability of Fe-EDTA complex. pH as an important environmental factor was 9.0 for the stability of chemical complex in the oxidation of hydrogen sulfide.

• Bulletin of the Korean Chemical Society
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• v.29 no.7
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• pp.1332-1334
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• 2008

Stable crystalline 1-Benzyl-4-aza-1-azonia-bicyclo[2.2.2]octane tribromide (BABOT), can be readily synthesized from the reaction of the corresponding bromide with $HNO_3$ and aqueous KBr. Selective Oxidation of a variety of dialkyl and alkyl Aryl sulfides to the corresponding sulfoxides in high yield was achieved by this reagent in solution ($CH_3CN/H_2O$) and solvent free conditions. The reaction proceeds under neutral and mild conditions and can be carried out easily at room temperature with regeneration of BABOT. In this method purification of products is straightforward and no over oxidation to sulfone was noted.