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Assessment of heavy metals in sediments of Shitalakhya River, Bangladesh

  • Al-Razee, A.N.M.;Abser, Md. Nurul;Mottalib, Md. Abdul;Rahman, Md. Sayadur;Cho, Namjun
    • Analytical Science and Technology
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    • v.32 no.5
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    • pp.210-216
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    • 2019
  • Concentrations of Cu, Zn, Fe, Mn, Ni and Cr have been estimated in sediments of the Shitalakhya River at Polash-Ghorashal area, Narsingdi, Bangladesh. 36 samples of sediments from nine sampling point at different locations of Shitalakhya River were collected to determine the concentration of Cu, Zn, Fe, Mn, Ni, Cr and the samples were analyzed by atomic absorption spectrophotometer (AAS). The obtained results were compared with national and international guidelines. The levels of heavy metal concentrations in sediments were found to decrease in the order of Fe > Mn > Zn > Ni > Cu > Cr, respectively. The heavy metal concentration in sediment of Shitalakhya was below the recommended safe limits of heavy metals by WHO, FAO and other international standards. Contamination factor (CF) of Zn and Cu at sampling point Fsd2 show higher (> 1) values due to the influence of external discrete sources like wastage catalysts of ZnO and CuO. Geo-accumulation index values of the study indicate as non-contaminated to moderately contaminate.

Effect of Sewage Sludge on the Yields and Chemical Properties of Soybean(Glycine max) and Carrot(Daucus carota) (하수슬러지 시용이 대두 및 당근의 수량과 화학적 특성에 미치는 영향)

  • Lee, In-Bog;Lim, Jae-Shin;Lim, Hyun-Taek;Chang, Ki-Woon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.4 no.1
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    • pp.53-60
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    • 1996
  • This study was carried out to investigate the effects on the growth of soybean and carrot, and these uptake of inorganic components, after the application of sewage sludge disgested anaerobically at wastewater treatment plant for about 25 days. With the application of the sludge, some chemical properties of soil was improved and heavy metals, as Pb, Cd, Cr, As and Hg, in finally harvested crops were not detected. With an increase in the application of the sludge, the uptake of N, P, K, and Ca in carrot was increased and also in the yield of two crops. In related to the quality of carrot, however, application of unmatured sewage sludge showed to deteriorate the visual quality with an irregularity of carrot's surface, despite of the increase of ${\beta}$-carotene concentration with an increased application of the sludge. The results suggest that for a land application of sewage sludge it should be necessarily stabilized by means such as composting.

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Intercomparison and Determination of Sediment by Instrumental Neutron Activation Analysis (중성자방사화분석을 이용한 퇴적물의 정량 및 비교연구)

  • 정용삼;문종화;정영주;박용준;이길용;윤윤열;이수형;김경태
    • Journal of the Korean Society of Groundwater Environment
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    • v.5 no.2
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    • pp.116-121
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    • 1998
  • For the application of study on pollution and conservation of environment determination of 33 elemental concetrations in different sediment samples were carried out using instrumental neutron activation analysis (INAA). For verification and evaluation of the analytical method, three standard reference materials (two NIST SRMs and one NRCC CRM) were chosen and the accuracy and precision of the analysis were estimated by comparison to the certified values. Under the optimum condition, the analytical procedure to apply a practical sample was estimated. Neutron irradiation of sample was done at the irradiation facilities (neutron flux, 1-3${\times}$10$\^$13/n/$\textrm{cm}^2$$.$s) of the TRIGA MARK-III and HANARO research reactor in the Korea Atomic Energy Research Institute. In addition, analysis of two IAEA's sediment was performed according to the pre-established analytical method. The analytical results of elements such as Al, As, Co, Cr, Fe, Sb and Zn by INAA were intercompared with those of WD-XRF, ICP-MS and AAS, and are relatively agreed with each other.

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Evaluation of Adhesion Properties of Arc PVD Coatings on Non-Nitrided and Nitrided Various Substrates (모재의 재질 및 질화층 형성에 따른 Arc PVD 코팅의 접합특성 평가)

  • Lee Jung-Min;Jun Sung-Jin;Ko Dae-Cheol;Kim Byung-Min
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.10 s.253
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    • pp.1179-1186
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    • 2006
  • This paper was designed to assess the adhesive properties of hard coatings on non-nitrided and nitrided various tool steels. Estimations of adhesion were done to scratch test which is mainly used in hard coating. The critical load$(L_c)$ between coating and substrate is defined through analysis of frictional load vs. normal load curve, signals of acoustic emission and optical observations. Coatings employed in this study are TiN, CrN and TiAlN, tools as substrates are STD11, STD61 and SKH51. It was classified to substrates with/without intermediate nitrided layer and hard coatings on substrate were deposited by arc PVD. Results showed that harder substrates and coatings give higher values of critical loads.

Evaluation of Adhesion properties of Arc PVD coatings for Micro Forming Die (미세성형용 금형 Arc PVD 코팅의 밀착력 평가)

  • Lee J. M.;Ko D. C.;Kim B. M.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.186-189
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    • 2005
  • This paper was designed to assess the adhesive properties of hard coatings on non-nitrided and nitrided various tool steels. Estimations of adhesion were done to scratch test which is mainly used in hard coating. The critical load(Lc) between coating and substrate is defined through analysis of frictional load vs. normal load curve, signals of acoustic emission and optical observations. Coatings employed in this study are TiN, CrN and TiAlN, tools as substrates are STD11, STD61 and SKH51. It was classified to substrates with/without nitrided layer and hard coatings on substrate were deposited by arc PVD. Results showed that harder substrates and coatings give higher values of critical loads.

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Microstructures and Hardness of Al-Si Coated 11%Cr Ferritic Stainless Steel, 409L GTA Welds (Al-Si 용융도금된 11%Cr 페라이트 스테인리스강, STS409L GTA 용접부의 미세조직과 경도)

  • Park, Tae-Jun;Kong, Jong-Pan;Na, Hye-Sung;Kang, Chung-Yun;Uhm, Sang-Ho;Kim, Jeong-Kil;Woo, In-Su;Lee, Jong-Sub
    • Journal of Welding and Joining
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    • v.28 no.3
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    • pp.92-98
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    • 2010
  • Ferritic stainless steels, which have relatively small thermal expansion coefficient and excellent corrosion resistance, are increasingly being used in vehicle manufacturing, in order to increase the lifetime of exhaust manifold parts. But, there are limits on use because of the problem related to cosmetic resistance, corrosions of condensation and high temperature salt etc. So, Aluminum-coated stainless steel instead of ferritic stainless steel are utilized in these parts due to the improved properties. In this investigation, Al-8wt% Si alloy coated 409L ferritic stainless steel was used as the base metal during Gas Tungsten Arc(GTA) welding. The effects of coated layer on the microstructure and hardness were investigated. Full penetration was obtained, when the welding current was higher than 90A and the welding speed was lower than 0.52m/min. Grain size was the largest in fusion zone and decreased from near HAZ to base metal. As welding speed increased, grain size of fusion zone decreased, and there was no big change in HAZ. Hardness had a peak value in the fusion zone and decreased from the bond line to the base metal. The highest hardness in the fusion zone resulted from the fine re-precipitation of the coarse TiN and Ti(C, N) existed in the base metal during melting and solidification process and the presence of fine $Al_2O_3$ and $SiO_2$ formed by the migration of the elements, Al and Si, from the melted coating layer into the fusion zone.

Fabrication and Characterization of Polycrystalline Silicon Solar Cells using Preferential Etching of Grain Boundaries (결정입계의 선택적 식각을 이용한 다결정 규소 태양전지의 제작과 특성)

  • Kim, Sang-Su;Kim, Cheol-Su;Lim, Dong-Gun;Kim, Do-Young;Yi, Jun-Sin
    • Proceedings of the KIEE Conference
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    • 1997.07d
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    • pp.1430-1432
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    • 1997
  • A solar cell conversion effiency was degraded by grain boundary effect in polycrystalline silicon. To reduce these effects of the grain boundaries, we investigated various influencing factors such as preferential chemical etching of grain boundaries, grid design, transparent conductive thin film, and top metallization along grain boundaries. Pretreatment in $N_2$ atmosphere and gettering by $POCl_3$ and Al were performed to obtain polycrystalline silicon of the reduced defect density. Structural, electrical, and optical properties of solar cells were characterized. Improved conversion efficiencies of solar cell were obtained by a combination of Al diffusion into grain boundaries on rear side, fine grid finger, top Yb metal grid on Cr thin film of $200{\AA}$ and buried contact metallization along grain boundaries.

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Behavior of the Surface Precipitation of Manganese Oxides during Hot-dip Galvanizing (용융아연 도금욕에서 망간 산화물의 표면석출 거동)

  • Lee, Ho Jong;Kim, Myung Soo
    • Journal of the Korean institute of surface engineering
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    • v.48 no.1
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    • pp.27-32
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    • 2015
  • Advanced high strength steels undergo recrystallization annealing in reducing gas atmosphere before galvanizing to improve mechanical properties. The selective oxidations of elements such as Mn, Si, Cr and Al during annealing decrease wettability of liquid zinc, resulting in bare spots and other defects. In this work, Fe-3wt%Mn steel sheet was annealed at $780^{\circ}C$ for 1200 sec. in 5% $H_2-N_2$ atmosphere and then dipped into zinc bath held at $460^{\circ}C$, which contained 0.2wt% dissolved Al. MnO crystallines in the average size of 200 nm were formed on the surface after annealing. It is estimated that MnO has been detached into bath with the formation and growth of inhibition layer with longer immersion time during galvanizing. No evidence of aluminothermic reduction of MnO has been found in this study.

Seasonal Variation and Statistical Analysis of Particulate Pollutants in Urban Air (도시대기립자상물질중 오염성분의 계절적 변동 및 통계적 해석)

  • 이승일
    • Journal of environmental and Sanitary engineering
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    • v.9 no.2
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    • pp.8-23
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    • 1994
  • During the period from Mar., 1991 to Feb., 1992 66 tSP samples were collected by Hi volume air sampler at 1 sampling site in Seoul and the amount of concentration of 21 components(SO$_{4}$$^{2-}$, NO$_{3}$$^{-}$, NH$_{4}$$^{+}$, Cl$^{-}$, Al, Ba, Ca, Cd, Cr, Cu, Fe, It Mg, Mn, Na, Ni, Pt Si, Ti, Zn, Zr ) were measured. And monthly and seasonal variation were surveyed and the principal component analysis( PCA ) were carried out with respect to these amount of pollutants, minimum of visibility and radiation on a horizontal surface. The total amount of soluble ion in water was high in order o(SO$_{4}$$^{2-}$> NO$_{3}$$^{-}$> N%'>Cl$^{-}$ and metal ion was high in order of Na> Ca>Si> Fe> Al> K> Mg> Zn> Pb> Cu>Ti> Mn > Ba> Cr> Zr> Ni> Cd. There was Seasonal variation in concentration for SO$_{4}$$^{2-}$, NH$_{4}$$^{+}$, Cl$^{-}$, Na, Al, Ca, Bt Mg, Fe and Si. It was assumed that the components of the highest concentration on April were depend on yellow sand and the frequency of wind velocity and direction. As the results of PCA, the amount of pollution components was able to characterized with two principal components(Z$_{1}$, Z$_{2}$ ). The first principal components Z$_{1}$ was considered to be a factor indicating the pollutants originated from natural generation and The second principal components Z$_{2}$ was considered to be a factor indicating the pollutants originated from human work. The monthly concentration of pollutants in ISP, minimum of visibility and radiation on a horizontal surface was possible to evaluate by the use of these two principal components Z$_{1}$ and Z$_{2}$ .

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The Effects of pH Change in Extraction Solution on the Heavy Metals Extraction from Soil and Controversial Points for Partial Extraction in Korean Standard Method (용출액의 pH 변화가 토양내 중금속 용출에 미치는 영향과 그에 따른 국내 토양 오염 공정시험방법의 문제점)

  • 오창환;유연희;이평구;이영엽
    • Economic and Environmental Geology
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    • v.36 no.3
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    • pp.159-170
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    • 2003
  • Heavy metals are extracted from Chonju stream sediment, roadside soils and sediments along Honam expressway, soils and tailings from mining area using three different methods (partial extraction in Standard Method, partial extraction method with maintaining 0.1 N of extraction solution and Sequential Extraction Method). In samples having buffer capacity against acid, pH 1 (0.1 N HCl) of extraction solution can not be maintained and pH of extraction solution increases up to 8.0 when partial extraction in Standard Method is used. The averages and ranges of HPE(heavy metals extracted using partial extraction in Standard Method)/HPEM(heavy metals extracted using partial extraction method with maintaining 0.1 N of extraction solution) values are 0.479 and 0.145~0.929 for Cd, 0.534 and 0.078~0.928 for Zn, 0.432 and 0.041~0.992 for Mn, 0.359 and 0.011~0.874 for Cu, 0.150 and 0.018~0.530 for Cr, 0.219 and 0.003~0.853 for Pb, and 0.088 and 1.73${\times}$10$^{-5}$~0.303 for Fe. These data indicate that the difference between HPE and HPEM is large in the order of Fe, Cr, Pb, Cu, Mn, Cd and Zn. The amounts of heavy metals extracted decreases in the follow order; Sum III(sum of fraction I, II, III in sequential extraction)>HPEM>Sum III (sum of fraction I and II)>HPE for Zn, Cd and Mn and Sum III>HPEM>HPE for Cr and Fe. In the case Cr, Sum II is lower than HPEM and higher than HPE. In case of Cu, extracted heavy metals is large in the order Sum IV>HPEM>Sum III HPE. HPE/HPEM value decreases with increasing the amount of HCl used for maintaining 0.1 N of extraction solution. For samples with high buffer capacity, HPE/HPEM value in all elements is lower than 0.2. On the other hand, for samples with low buffer capacity, HPE/HPEM value are over 0.2 and many samples have values higher than 0.6 for Zn, Cd Mn and Cu due to the small difference between Sum II and Sum III, and relatively higher mobility. However, for Fe and Cr, HPE/HPEM value is below 0.2 even for samples with low buffer capacity due to their low mobility and big difference between Sum II and Sum III. This study indicates that the partial extraction method in Korean Standard Method of soil is not suitable for an assessment of soil contamination in area where buffer capacity of soil can be decreased or lost because of a long term exposure to environmental damage such as acidic rain.