강구조물의 고력볼트 마찰접합부에 있어서 마찰면의 부식은 장기적으로 마찰력 감소와 접합부 내력저하를 초래한다. 본 연구는 고력볼트 접합부의 부식을 방지하고 소요 역학적 성질을 만족시키기 위해 접합부의 마찰면에 Zn/Al 금속용사 방청처리 한 고력볼트 접합부를 대상으로 마찰면의 표면처리방법과 피막두께를 주요 변수로 하여 인장시험을 실시하였고, 실험으로 부터 마찰면 표면거칠기와 미끄럼계수를 측정하였다. 무도장 샌드블라스트 처리한 접합부 및 샌드블라스트 처리 후 금속용사를 실시한 볼트 접합부의 미끄럼 계수는 국내 규준의 규정 값과 비교하여 동등 이상의 우수한 미끄럼계수 값을 나타냈다.
Hydrochloride acid salts of new N2O2 tetradentate ligands containing amine and phenol N,N'-bis(2-hydroxybenzyl)-o-phenylenediamine(H-BHP), N,N'-bis(5-bromo-2-hydroxybenzyl)-o-phenylenediamine(Br-BHP), N,N'-bis (5-chloro-2-hydroxybenzyl)-o-phenylene-diamine(Cl-BHP), N,N'-bis(5-methyl-2-hydroxybenzyl)-o-phenylene-diamine (Me-BHP) and N,N'-bis(5-methoxy-2-hydroxybenzyl)-o-phenylenediamine(MeO-BHP) were synthesized. The ligands were characterized by elemental analysis, mass and NMR spectroscopy. The elemental analysis showed that the ligands were isolated as dihydrochloride salt. The potentiometry study revealed that the proton dissociation constants(logKnH) of ligands and stability constants (logKML) of transition and heavy metals complexes. The order of the stability constants of each metal ions for ligands was Br-BHP < Cl-BHP < H-BHP < MeO-BHP < Me-BHP.
The contents of five heavy metals such as lead, cadmium, zinc, copper and manganese in soil and vegetables collected from four sites in Busan district with composite sampling method were determined with ICP emission spectrometer. The ranges of their contents in soil were lead, 1.65~4.36 ppm; cadmium, 0.05~0.09 ppm; zinc, 6.33~11.09 ppm; copper, 0.44~1.35 ppm; manganese, 8.40~19.39 ppm, respectively. These contents were lower than the Clarke number. The range of heavy metal contents in four vegetables such as lettuce, radish and its roots, spinach and cabbage were lead, 0.09~0.48 ppm; cadmium, 0.01~0.08 ppm; zinc, 1.81~14.62 ppm; copper, 0.14~1.87 ppm; manganese, 0.71~14.5 5ppm with the order of Zn(7.30 ppm)>Mn(4.35 ppm)>Cu(0.53 ppm)>Pb(0.19 ppm)>Cd(0.04 ppm) in average contents. The average transfer ratio of metals from soil to vegetables was order of Zn(77.8 %)> Cd(37.5 %)>Cu(34.5 %)>Mn(18.6 %)>Pb(6.7 %). In case of the same cultivating soil, the transfer ratio could be expected to the order of spinach<radish<cabbage<lettuce for copper, lettuce≈cabbage<radish<spinach for manganese, respectively.
Mesoporous silicas for heavy metals adsorption were prepared by co-condensation of surfactant as a template and Ludox HS-40 as a silica precursor.
Various mesoporous silicas with the introduction of chelating ligands (mercaptopropyl and aminopropyl groups) were synthesized to remove heavy metal ions from aqueous solutions. The surface modification was conducted with a co-condensation process using the sequential or simultaneous addition of mesoporous silica and high concentration of the organosilane(3-mercaptopropyltrimethoxysilane and 3-aminopropyltriethoxysilane). These materials have been characterized by elemental analysis, XRD, SEM and TEM analysis.
Adsorbents synthesized with 3-mercaptopropyltrimethoxysilane and 3-aminopropyltriethoxysilane shows a high loading capacity for Hg(II), Pb(II) , Cd(II) and anion Cr(VI). Especially the one synthesized with a mercaptopropyl function has the highest adsorption capacity for Hg(II) and Cd(II).
본 연구에서는 석탄 광산배수에 함유된 중금속을 부유선별로 제거하기에 앞서 부유선별 조건에 영향을 미치는 철, 망간, 알루미늄 이온의 침전특성을 알아보았다. Fe(III), Mn(II), Al(III) 이온을 NaOH와 반응시켜 1 h 동안 침전시키면 Fe(III)은 pH 5.0 이상에서, Mn(II)은 pH 10.0 이상에서 그리고 Al(III)은 pH 6.0~9.0의 범위에서 대부분 침전되어 여액에 1.0mgL-1 이하로 잔류되었다. Fe(III), Mn(II), Al(III)의 혼합 용액에 포수제인 올레인산나트륨을 첨가하였을 경우, 각각의 중금속 이온은 올레인산나트륨과 반응하여 불용성 염을 거의 형성하지 않았기 때문에 침전 부선법으로 광산배수에 함유된 중금속을 제거해야 하는 것으로 나타났다.