• Applied Chemistry for Engineering
• /
• v.27 no.2
• /
• pp.165-170
• /
• 2016

In this study, we investigated the cause of the decrease in activities of $VO_x/TiO_2$ SCR catalyst used for the burner reactor at a scale of $150000Nm^3/hr$ using X-ray diffraction (XRD), brunauer-emmett-teller (BET), atomic emission spectroscopy inductively coupled plasma (AES ICP), $H_2$ temperature programmed reduction ($H_2$-TPR), and $NH_3$ temperature programmed desorption ($NH_3$-TPD) analysis. Since the crystallization of the $VO_x$ and phase transition of $TiO_2$ did not occur, it was concluded that the catalyst was not deactivated by the thermal effect. In addition, from the elemental analysis showing that a large quantity of calcium was detected but not sulfur, the deactivation process of the $VO_x/TiO_2$ SCR catalyst was mainly caused by Ca but not by $SO_2$. The calcium was also found to decrease the catalytic activity by means of reducing $NH_3$ adsorption.

• Journal of Life Science
• /
• v.27 no.4
• /
• pp.435-441
• /
• 2017

Perchlorate ($ClO_4^-$) is an emerging contaminant detected in soil, groundwater, and surface water. Previous study revealed bacterial community in the enrichment culture tdegraded perchlorate using elemental sulfur as an electron donor. Quantitative and qualitative molecular methods were employed in this study to investigate archaeal community in the enrichment culture. Real-time qPCR showed that archaeal 16S rRNA gene copy number in the culture was about 1.5% of bacterial 16S rRNA gene copy number. This suggested that less archaea were adapted to the environment of the enrichment culture and bacteria were dominant. DGGE banding pattern revealed that archaeal community profile of the enrichment culture was different from that of the activated sludge used as an inoculum for the enrichment culture. The most dominant DGGE band of the enrichment culture was affiliated with Methanococci. Further research is necessary to investigate metabolic role of the dominant archaeal population to better understand microbial community in the perchlorate-reducing enrichment culture.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.26 no.3
• /
• pp.55-61
• /
• 2018

This study evaluated if the selected samples meets the Solid Refuse Fuel quality criteria in Korea. Biomass and plastic wastes generated in D City were mixed in diverse ratio. When the biomass content was about 40%, the moisture content was close to the SRF criteria and was measured to be 9.8%. The ash contents were analyzed up to 4.19%, and the lower calorific values based on Steuer, Dulong Equation and Bomb Calorimeter were at least 4,851, 4,181 and 3,847 kcal/kg, respectively. As a result of the elemental analysis, sulfur and chloride content were measured up to 0.05%. Those values satisfied the SRF criteria. Also, heavy metals(Hg, Cd, Pb, As) were analyzed to be below the SRF criteria. This makes it possible to use efficiently the wood byproducts abandoned in the woods, and the physical properties of wood being weak to moisture can be supplemented with plastics. Consequently, if plastic and biomass were well mixed and made into SRF, it would overcome the problem of shortening the life span of incineration facilities due to the high temperature of plastic wastes in the incinerator.

• Korean Journal of Heritage: History & Science
• /
• v.51 no.4
• /
• pp.224-233
• /
• 2018

Thirty-three Early Iron Age bronzes at the sites of Hoam-dong in Chungju and Cheongsong-ri in Buyeo were investigated in order to study the manufacturing technique and the provenance of lead. Chemical analysis using X-ray fluorescence showed that 33 bronzes consist of copper(Cu), tin(Sn) and lead(Pb) served as major elements. Major and minor elemental analyses by EPMA were performed on two mirrors and 2 weapons of the bronzes investigated. The results shows that bronze mirrors from Chungju and Buyeo were high-tin bronzes(> 30 wt%). And 20% of tin and 5% of lead were founded in bronze weapons. Iron, zinc, arsenic, silver, nickel, sulfur and cobalt detected in four bronzes as minor and trace elements. The four bronzes were alloyed considering their function and were not heat treated after casting due to their high tin content. Lead isotope analysis using TIMS indicates that thirty-three bronzes were distributed southern Korea peninsula except Zone 1. As a result, lead raw materials came from various regions in Korean Peninsula not from Gyeongsang-do regions. The manufacturing techniques of bronze ware generalized at this age, and bronze was produced in various sites using raw materials from various sources.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.9 no.2
• /
• pp.64-72
• /
• 2004

We measured the vertical profiles of $O_2$, H$_2$S, and pH in sediment pore water beneath marine cage fish farms using a microsensor with a 25 ${\mu}{\textrm}{m}$ sensor tip size. The sediments are characterized by high organic material load. The oxygen consumption, hydrogen sulfide oxidation, and sulfate reduction rates in the microzonations (derived from the vertical distribution of chemical species concentration) were estimated by adapting a simple one-dimensional diffusion-reaction model. The oxygen penetration depth was 0.75 mm. The oxic microzonations were divided into upper and lower layers. Due to hydrogen sulfide oxidation within the oxic zone, the oxygen consumption rate was higher in the lower layer. The total oxygen consumption rate integrated with reaction zone depth was estimated to be 0.092 $\mu$mol $O_2$cm$^{-2}$ hr$^{-1}$ . The total hydrogen sulfide oxidation rate occurring within 0.7 mm thickness was estimated to be 0.030 $\mu$mo1 H$_2$S cm$^{-2}$ hr$^{-1}$ , and its turnover time in the oxic sediment layer was estimated to be about 2 minutes. This suggests that hydrogen sulfide was oxidized by both chemical and microbial processes in this zone. The molar consumption ratio, calculated to be 0.84, indicates that either other electron accepters exit on hydrogen sulfide oxidation, or elemental sulfur precipitation occurs near the $O_2$- H$_2$S interface. Total sulfate reduction flux was estimated to be 0.029 $\mu$mol cm$^{-2}$ hr$^{-1}$ , which accounted for more than 60% of total $O_2$ consumption flux. This result implied that the degradation of organic matter in the anoxic layer was larger than in the oxic layer.

• Journal of Mushroom
• /
• v.16 no.2
• /
• pp.111-117
• /
• 2018

This study was conducted to compare the composition and antioxidant activity of 1- and 2-year-old Poria cocos Wolf cultivated at a mortuary and cemetery. An elemental analyzer test showed oxygen, carbon, hydrogen, nitrogen, and sulfur to be present at concentrations of 45~46%, 39~41%, 6.06~6.1%, 0.21~0.22%, and 0%, respectively. No differences in composition were observed among samples. Eleven minerals (S, Ca, Mg, P, As, Se, Cu, Fe, Pb, Zn, and Cd) found in P. cocos cultivated at the mortuary and cemetery were analyzed by inductively coupled plasma mass spectrometry (ICP). The levels of S, Fe, Mg, and Zn in P. cocos were higher in cemetery-cultivated samples than in mortuary-cultivated samples. A 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay for antioxidant activity revealed half-maximal inhibitory concentration ($IC_{50}$)values of P. cocos to be 8.601 mg/mL (mortuary, 1 year old), 12.85 mg/mL (cemetery, 1 year old), 1.23 mg/mL (mortuary, 2 years old), and 1.18 mg/mL (landfill, 1 year old). A 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay revealed $IC_{50}$ values of 15.85 mg/mL (mortuary, 1 year old),14.59 mg/mL(cemetery, 1 year old), 3.9 mg/mL (mortuary, 2 years old), and 14.92 mg/mL (cemetery, 1 year old). The results showed a concentration-dependent effect. Two-year-old mortuary-cultivated P. cocos had the highest antioxidant activity among samples. Ultrastructure analysis with a field emission scanning electron microscope (FE-SEM) showed no obvious differences among samples.