• Economic and Environmental Geology
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• v.42 no.5
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• pp.395-401
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• 2009

The smectite-illite (SI) reaction is a ubiquitous process in siliciclastic sedimentary environments. For the last 4 decades the importance of smectite to illite (S-I) reaction was described in research papers and reports, as the degree of the (S-I) reaction, termed "smectite illitization", is linked to the exploration of hydrocarbons, and geochemical/petrophysical indicators. The S-I transformation has been thought that the reaction, explained either by layer-by-layer mechanism in the solid state or dissolution/reprecipitation process, was entirely abiotic and to require burial, heat, and time to proceed, however few studies have taken into account the bacterial activity. Recent laboratory studies showed evidence suggesting that the structural ferric iron (Fe(III)) in clay minerals can be reduced by microbial activity and the role of microorganisms is to link organic matter oxidation to metal reduction, resulting in the S-I transformation. In abiotic systems, elevated temperatures are typically used in laboratory experiments to accelerate the smectite to illite reaction in order to compensate for a long geological time in nature. However, in biotic systems, bacteria may catalyze the reaction and elevated temperature or prolonged time may not be necessary. Despite the important role of microbe in S-I reaction, factors that control the reaction mechanism are not clearly addressed yet. This paper, therefore, overviews the current status of microbially mediated smectite-to-illite reaction studies and characterization techniques.

• Journal of Environmental Impact Assessment
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• v.29 no.5
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• pp.350-362
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• 2020

In this study, nano Fe°-impregnated biochar (INPBC) was prepared using pruning residues and one-pot synthetic method and evaluated its performance as an amendment agent for the stabilization of arsenic-contaminated soil. For the preparation of INPBC, the mixture of pruning residue and Fe (III) solution was heated to 220℃ for 3hr in a teflon-sealed autoclave followed by calcination at 600℃ under N₂ atmosphere for 1hr. As-prepared INPBC was characterized using FT-IR, XRD, BET, SEM. For the stabilization test of as-prepared INPBC, As-contaminated soils (Soil-E and Soil-S) sampled from agricultural sites located respectively near E-abandoned mine and S-abandoned mine in South Korea were mixed with different of dosage of INPBC and cultivated for 4 weeks. After treatment, TCLP and SPLP tests were conducted to determine the stabilization efficiency of As in soil and showed that the stabilization efficiency was increased with increasing the INPBC dosage and the concentration of As in SPLP extractant of Soil-E was lower than the drinking water standard level of Ministry of Environment of South Korea. The sequential fractionation of As in the stabilized soils indicated that the fractions of As in the 1st and 2nd stages that correspond liable and known as bioavailable fraction were decreased and the fractions of As in 3rd and 4th stages that correspond relatively non-liable fraction were increased. Such a stabilization of As shows that the abundant nano Fe° on the surface of INPBC mixed with As-contaminated soils played the co-precipitation of As leaching from soil by surface complexation with iron. The results of this study may imply that INPBC as a promising amendments for the stabilization of As-contaminated soil play an important role.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.193-200
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• 2010

This study evaluated treatability of soluble Mn(II) using multifunctional sand media simultaneously coated with iron and manganese. In the preparation of IMCS(Iron and Manganese Coated Sand), 0.05 M Mn(II) solution and Fe(III) solution was mixed with sand at pH 7. The mineral type of IMCS was identified as the mixture of ${\gamma}-MnO_2$, goethite and magnetite($F_{e3}O_4$). The contents of Mn and Fe coated onto sand were 826 and 1676 mg/kg, respectively. The $pH_{pzc}$ of IMCS was measured as 6.40. The removal of soluble Mn(II) using IMCS and oxidants such as NaOCl and $KMnO_4$ was investigated with variation of the solution pH, reaction time and Mn(II) concentration in a batch test. The removal of Mn(II) on IMCS was 34% at pH 7.4 and the removals of Mn(II) on IMCS in the presence of NaOCl(13.6 mg/L) at pH 7 and $KMnO_4$(4.8 mg/L) at pH 7.6 were 96% and 89%, respectively. The removal of Mn(II) using IMCS and oxidants followed a typical cationic type, showing a gradual increase of removal as the solution pH increased. The removal of Mn(II) was rapid in the first 6 hrs and then a constant removal was observed. The maximum removed amount of Mn(II) on IMCS-alone and IMCS in the presence of oxidants such as NaOCl(13.6 mg/L) and $KMnO_4$(4.8mg/L) were 833.3, 1428.6 and 1666.7 mg/kg, respectively. Mn(II) removal onto the IMCS in the presence of oxidants was well described by second-order reaction and Langmuir isotherm expression.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.289-293
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• 2005

Nowadays there are many sun protection cosmetics including organic or inorganic UV filter as an active ingredient. Chemically stable inorganic sunsEreen agents, usually metal oxides, we widely employed in high SPF products. Titanium dioxide is one of the most frequently used inorganic UV filters. It has been used as pigments for a long period of cosmetic history. With the development of micronization techniques, it becomes possible to incorporate titanium dioxide in sunscreen formulations without whitening effect and it becomes an important research topic. However, there are very few works related to quantitations of titanium dioxide in sunscreen products. In this research, we analyzed amounts of titanium dioxide in sunscreen cosmetics by adapting redof titration, reduction of Ti(IV) to Ti(III) and reoxidation to Ti(IV). After calcification of other organic ingredients of cosmetics, titanium dioxide is dissolved by hot sulfuric acid. The dissolved Ti(IV) is reduced to the Ti(III) by adding aluminum metals. The reduced Ti(III) is titrated against a standard oxidizing agent, Fe(III) (ammonium iron(III) sulfate), with potassium thiocyanate as an indicator In order to test accuracy and applicability of the proposed method, we analyzed the amounts of titanium dioxide in four types of sunscreen cosmetics, such as cream, make-up base, foundation and powder, after adding known amounts of titanium dioxide $(1{\sim}25w/w%)$. The percent recoveries of the titanium dioxide in four types of formulations were in the range between 96 and 105%. We also analyzed 7 commercial cosmetic products labeled titanium dioxide as an ingredient and compared the results with those of obtained from ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry), one of the most powerful atomic analysis techniques. The results showed that the titrated amounts were well coincided with the analyzed amounts of titanium dioxide by ICP-AES. Although instrumental analytical methods, ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) and ICP-AES, are the best for the analysis of titanium, it is hard to adopt because of their high prices for small cosmetic companies. It was found that the volumetric method presented here gat e quantitative and reliable results with routine lab-wares and chemicals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.291-299
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• 1997

This study was accomplished to investigate the prevalence of obesity in 371 Kumi-city middle school students. The means of this study were anthropometric measurement and questionnaires about nutrient intake and energy expenditure. Anthropometric measurements were height, weight, arm circumference and skinfold thickness(biceps, triceps, subscapular, supraliac, calf). The results obtained are as follows: Energy, calcium, iron intake for boys were lower than RDA. Iron intake was low in girls. Energy intake is lower than energy expenditure and RDA for boys. Energy intake, energy expenditure and RDA for girls were balanced. The average height, weight and arm circumference of boys were respectively 160.0cm, 49.4kg, 23.1cm and those of girls were respectively 155.9cm, 48.9kg, 22.6cm. Prevalence of obesity was respectively 5%, 4%, 7%, 4%, 59%, 15%, 14%, 24% for boys and 6%, 10%, 13%, 9%, 30%, 7%, 1%, 3496 for girls by RBW, BMI, RI, OI, %Fat I, %FatII, %FatIII, triceps. Correlation between subscapular skinfold thickness and BMI, RI, OI and %FatII showed high.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.1028-1033
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• 2010

The effects of delta-aminolevulinic acid (DALA) or chito-oligosaccharide (COS) in layer diets on production performance, egg quality and hematological characteristics were investigated in this 8-week trial. Two hundred and seventy 27-week-old (Hy-Line brown) layers were randomly assigned to 5 treatments with 9 replications per treatment. Dietary treatments were i) Control (basal diet); ii) DALA1 (basal diet+DALA 2 mg/kg); iii) DALA2 (basal diet+DALA 4 mg/kg); iv) COS1 (basal diet+COS 100 mg/kg) and v) COS2 (basal diet+COS 200 mg/kg). In this study, no significant difference was observed in feed intake and egg shell quality (eggshell breaking strength and egg shell thickness) among treatments. The inclusion of DALA increased egg production during the first 4 weeks. Egg weight was increased in both DALA (quadratic, p<0.05) and COS (linear, p<0.05) treatments compared with the control treatment. Laying hens fed the DALA treatment had an increased yolk color unit (quadratic, p<0.05) and haugh unit (linear, p<0.05) compared with the control group. Similarly, these characteristics were also affected by COS treatments, with both values being linearly increased (p<0.05) in COS treatments compared with the control treatment. Additionally, birds fed DALA treatments significantly increased (quadratic, p<0.05) the number of RBC, WBC and lymphocytes compared with the control treatment. Dietary DALA supplementation linearly increased (p<0.05) the serum iron concentration at the end of the 8th week. The inclusion of COS increased (linear, p<0.05) the concentration of RBC, WBC and lymphocytes compared with the control treatment. In conclusion, dietary DALA at the lower dosage (2 mg/kg) could exert better effects in laying hens than higher dosage (4 mg/kg). Birds fed DALA supplemented diet had an increased iron availability, egg weight, eggshell quality and immunity. Moreover, the inclusion of COS (200 mg/kg) can increase egg weight, eggshell quality and immunity in laying hens. Therefore, both the utilization of COS and DALA could be considered as a new strategy for optimizing egg quality and health condition of laying hens.

• Clean Technology
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• v.7 no.1
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• pp.75-80
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• 2001

In this study, hexavalent chromium (Cr(VI)) plating wastewater in strong acidic condition was treated by reduction and alkalization. Ferrous sulfate ($FeSO_4$), known to reduce Cr(VI) to Cr(III) rapidly at acidic pH, was used as a reductant of Cr(VI). The optimum reduction condition of Cr(VI) was observed at iron to chromium dose ratio of 3:1 by mole concentration. The precipitation of Cr(III) as $Cr(OH)_3$, was achieved by the pH adjustment in the limestone aeration bed. The precipitates were removed less than the upper limit of chromium for effluent at pH over 5.0. The continuous removal of Cr(VI) was performed using the process consisting of reduction vessel, limestone aeration bed, and sedimentation tank coupled with metal screen membrane. As pH was maintained around 5.0 in the limestone aeration bed, insoluble chromic hydroxide flocs was formed continuously. Most chromic hydroxide flocs were filtered by the metal screen membrane with 1450 mesh size, and the treated water to meet the upper limits of chromium for effluent (Cr Conc. 0.25~0.90 mg/l) was obtained in 30 minutes. Periodic backwashing decreased the fouling on the membrane rapidly.

• Membrane Journal
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• v.26 no.6
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• pp.480-489
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• 2016

In this study, the PVdF/MGO composite nanofiber membranes (PMGs) introducing Iron oxide-Graphene oxide ($Fe_3O_4/GO$, Metallic graphene oxide; MGO) was prepared via electrospinng method and its arsenic removal characteristics were investigated. The thermal treatment was carried out to improve the mechanical strength of nanofiber membranes and then the results showed that of outstanding improvement effect. However, in case of PMGs, the decreasing tendency of mechanical strength was indicated as increasing MGO contents. From the results of pore-size analysis, it was confirmed that the porous structured membranes with 0.3 to $0.45{\mu}m$ were prepared. For the water treatment application, the water flux measurement was carried out. In particular, PMG2.0 sample showed about 70% improved water flux results ($153kg/m^2h$) compared to that of pure PVdF nanofiber membrane ($91kg/m^2h$) under the 0.3 bar condition. In addition, the PMGs have indicated the high removal rates of both As(III) and As(V) (up to 81% and 68%, respectively). Based on the adsorption isotherm analysis, the adsorption of As(III) and As(V) ions were both more suitable for the Freundlich. From all of results, it was concluded that PVdF/MGO composite nanofiber membranes could be utilized as a water treatment membrane and for the Arsenic removal applications.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.359-371
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• 2019

To optimize the expression and secretion of ferritin protein associated with ion storage in the mushroom, Pleurotus eryngii, a recombinant secretion vector, harboring the ferritin gene, was constructed using a pPEVPR1b vector under the control of the CaMV 35S promoter and signal sequence of pathogen related protein (PR1b). The ferritin gene was isolated from the T-Fer vector following digestion with EcoRI and HindIII. The gene was then introduced into the pPEVPR1b secretion vector, and it was then named pPEVPR1b-Fer. The recombinant vector was transferred into P. eryngii via Agrobacterium tumefaciens-mediated transformation. The transformants were selected on MCM medium supplemented with kanamycin and its expression was confirmed by SDS-PAGE and western blotting. Expression of ferritin protein was optimized by modifying the culture conditions such as incubation time and temperature in batch and 20 L airlift type fermenter. The optimal conditions for ferritin production were achieved at 25℃ and after incubating for 8 days on MCM medium. The amount of ferritin protein was 2.4 mg/g mycelia, as measured by a quantitative protein assay. However, the signal sequence of PR1b (32 amino acids) seems to be correctly processed by peptidase and ferritin protein may be targeted in the apoplast region of mycelia, and it might not be secreted in the culture medium. The iron binding activity was confirmed by Perls' staining in a 7.5% non-denaturing gel, indicating that the multimeric ferritin (composed of 24 subunits) was formed in P. eryngii mycelia. Mycelium powder containing ferritin was tested as a feed additive in broilers. The addition of ferritin powder stimulated the growth of young broilers and improved their feed efficiency and production index.

• Journal of the Mineralogical Society of Korea
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• v.16 no.1
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• pp.1-17
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• 2003

The chemical composition of the arsenopyrite Ib adjoining“triple mutual contact”arsenopyrite + pyrite + hexagonal pyrrhotite may serve as a useful geothermometer in Stage II. In this study it corresponds to temperature T=33$0^{\circ}C$ and f( $S_2$)=10$^{-9.5}$ atm. And the pyrite-hexagonal pyrrhotite buffer curve indicates the probable range of the two variables; T= 315∼345$^{\circ}C$, and f( $S_2$)=10$^{-1}$0.5/∼10$^{-9}$ atm. The present antimony-bearing arsenopyrite (arsenopyrite Ic) is characterized by relatively high content of antimony, ranging from 4.95 to 8.91 percent Sb by weight and excess of iron and deficiency of anions are evident. Such a high antimonian arsenopyrite has never been known within single grain. But being the high content of antimony as in the arsenopyrite Ic, it does not serve as a geothermometer. The results of microprobe analyses for four pairs of asenopyrite and sphalerite in Stage III indicate the temperature range from 310 to 34$0^{\circ}C$, and sulphur fugacity range from 10$^{-10}$ ∼10$^{-9}$ atm. These values seem to correspond with those inferred from the Fe-As-S system.m..