• Title, Summary, Keyword: $CaCO_3$ preparation

Search Result 85, Processing Time 0.049 seconds

A Study on Heavy Metal Adsorption of the Submicron HAP (초미립 Hydroxy Apatite의 중금속 흡착에 관한 연구)

  • 안영필;김복희;황재석;신건철
    • Journal of the Korean Ceramic Society
    • /
    • v.27 no.1
    • /
    • pp.1-6
    • /
    • 1990
  • Preparation and heavy metal ion adsorption of sumicron hydroxy apatite were studied in this experiment. Submicron HAP was synthesized with Ca(OH)2 solution and H3PO4.Ca(OH)2 solution was made from water-quenching of CaCO3 heated at 1, 00$0^{\circ}C$ and 20%-H3PO4 was dropped into this Ca(OH)2 solution heated at 8$0^{\circ}C$. XRD pattern of prepared powder showed HAP crystal. The average particle size and sahpe of HAP were 0.25${\mu}{\textrm}{m}$ and sphere type. As a adsorbent, 1.0g of the prepared HAP powder in 1 liter of artifical 5ppm heavy matal waste water was sufficient, and more effective at pH7-9.

  • PDF

Studies on the Preparation of Precipitated Calcium Carbonate(I) : Formation and Transformation of Amorphous Calcium Carbonate (침강성탄산칼슘의 제조에 관한 연구(I) : 비정질탄산칼슘의 생성과 전이)

  • Ha, Ho;Park, Seung-Soo;Lee, Hee-Cheol
    • Applied Chemistry for Engineering
    • /
    • v.3 no.3
    • /
    • pp.522-526
    • /
    • 1992
  • Carbonation process of an aqueous solution of $Ca(OH)_2$ with $CO_2$ gas at $10^{\circ}C$ has been studied to investigate the formation and transformation processes of amorphous calcium carbonate. It was suggested that the amorphous calcium carbonate consisting of spherical particles with the diameter in the range of $0.02{\sim}0.05{\mu}m$ be a non-stoichiometric $CaCO_3$ phase containing small amounts of $H_2O$ and small incorporations of $HCO^-_3$. Amorphous $CaCO_3$ is unstable in the aqueous solution and converts to calcite, and its morphology depends on the carbonate species present in the slurry such that with [$CO_3^{2-}$] prevailing, chain-like calcite composed of ultrafine colloidal particles and with [$HCO^-_3$] prevailing, rhombohedral particles of calcite are formed respectively. Therefore, morphological control of calcium carbonate crystals could be expected by the adequate controls of transformation process of the amorphous calcium carbonate.

  • PDF

Preparation of Surface-Hydrolyzed Cellulose Acetate Fibers and Their Applications to LCD Rubbing Cloth (표면가수분해된 셀룰로오스 아세테이트 섬유의 제조 및 LCD 러빙포로의 응용)

  • Kim, Hyun-Sun;Kim, Young Ho
    • Polymer(Korea)
    • /
    • v.37 no.1
    • /
    • pp.52-60
    • /
    • 2013
  • Partially hydrolyzed cellulose acetate (CA) fibers were prepared by treating CA fibers in aqueous $Na_2CO_3$ solutions of various concentrations. The deacetylation of CA fibers was confirmed through FTIR spectra and WAXD patterns. The hydrolysis was confined to the surface part of the CA fiber by controlling the treatment conditions. The resultant fibers had a sheath-core structure with a sheath component of regenerated cellulose and a core of non-hydrolyzed cellulose acetate. The SEM images of the surface-hydrolyzed CA fibers, the core of which was dissolved out using acetone as the solvent, showed that the sheath thickness increased with increasing alkaline concentration, indicating an increase in the hydrolyzed fiber, i.e., regenerated cellulose. Polarized FTIR analysis of the polyimide film rubbed with velvet fabrics of surface-hydrolyzed CA fibers showed that polyimide molecules were preferentially oriented to the rubbing direction.

Preparation of Copper Nanoparticles in Cellulose Acetate Polymer and the Reaction Chemistry of Copper Complexes in the Polymer

  • Shim, Il-Wun;Noh, Won-Tae;Kwon, Ji-Woon;Jo, Jung-Young;Kim, Kyung-Soo;Kang, Dong-Hee
    • Bulletin of the Korean Chemical Society
    • /
    • v.23 no.4
    • /
    • pp.563-566
    • /
    • 2002
  • Copper complexes have been directly incorporated into cellulose acetate (CA) and the resulting light blue colored homogeneous films of 5-20 wt.% copper acetate complex concentrations are found to be thermally stable up to 200 $^{\circ}C$. The reaction chem istry of Cu in CA has been investigated by reacting them with small gas molecules such as CO, H2, D2, O2, NO, and olefins in the temperature range of 25-160 $^{\circ}C$, and various Cu-hydride, -carbonyl, -nitrosyl, and olefin species coordinated to Cu sites in CA are characterized by IR and UV/Vis spectroscopic study. The reduction of Cu(II) complexes by reacting with H2 gas at the described conditions results in the formation of Cu2O and copper metal nanoparticles in CA, and their sizes in 30-120 nm range are found to be controlled by adjusting metal complex concentration in CA and/or the reduction reaction conditions. These small copper metal particles show various catalytic reactivity in hydrogenation of olefins and CH3CN; CO oxidation; and NO reduction reactions under relatively mild conditions.

Purification and Characterization of ($Ca^{2+}$+$Mg^{2+}$)-ATPase of Sarcoplasmic Reticulum from Rat Skeletal Muscle (쥐 근소포체의 ($Ca^{2+}$+$Mg^{2+}$)-ATPase의 분리정제와 그 효소특성에 관하여)

  • Lee, Jong-Soon;Ha, Doo-Bong;Chung, Chin-Ha
    • The Korean Journal of Zoology
    • /
    • v.28 no.1
    • /
    • pp.31-43
    • /
    • 1985
  • The $(Ca^{2+}+Mg^{2+})$-ATPase has been purified homogeneously from sarcoplasmic reticulum of rat skeletal muscle by sucrose density gradient centrifugation. The purified enzyme has a molecular weight of 115,000 as judged by polyacrylamide gel electrophoresis in the presence of sodium dedecyl sulfate, and therefore has the same size of the enzyme in rabbit and chick skeletal muscle. $Ca^{2+}, Mg^{2+}, Fe^{2+}, Co^{2+}, and Mn^{2+}$ at 50 $\\muM$ show stimulatory effect on the ATP-ase, while $Zn^{2+}, Cu^{2+}, and Hg^{2+}$ inhibit it at the same concentration. The ATPase activity is insensitive to antimalarial drugs such as quinine and quinacrine, but is sensitive to inhibition by p-hydroxymecurie benzoate and phenylmethylsulfonylfluoride. The enzyme has optimum pH of 6 to 7 and Km value for ATP is estimated to be 98 $\\muM$. Thus, a number of biochemical properties of this enzyme appear to be different from those of the enzyme that have been isolated from rabbit skeletal muscle. The $(Ca^{2+}+Mg^{2+})$-ATPase appears to be selectively degraded in microsomal fraction. The activity of metalloendoprotease is evident in the microsomal preparation when assayed by radioactively labeled protein substrate, such as $^{3}H-casein and $^{125}I$-insulin. However, it is presently unclear whether the metalloendoprotease is responsible for the degradation of the $(Ca^{2+}+Mg^{2+})$-ATPase.

  • PDF

Preparation and Electrochemical Properties of Pr1-x (Sr, Ca)xCoO3 Cathode Materials for Zinc Air Batteries (아연공기전지용 Pr1-x (Sr, Ca)xCoO3 양극촉매 제조 및 전기화학적 특성)

  • Heo, Sang-Hun;Eom, Seung-Wook;Kim, Hyun-Soo
    • Journal of the Korean Electrochemical Society
    • /
    • v.12 no.4
    • /
    • pp.342-348
    • /
    • 2009
  • Zn/Air secondary batteries are high energy density type and environment-friendly. Also, they have safer properties than batteries of other type by low manufacturing cost and using the electrolyte solution. But, they have a weak concerning large output discharge. Oxygen evolution reaction(OER) and oxgen reduction reaction(ORR) in aqueous solution make a result of a decrease of cell efficiency and life span. Therefore, to minimize the voltage drop from between OCV and charge/discharge voltage is key point. The problem should be solved through developing catalysts of high efficiency. In this study, we synthesized $Pr_{1-x}(Sr,\;Ca)_x\;CoO_3$ powders by citric method and then measured physical characteristics of each powder by XRD, SEM, TGA etc. We examined its electrochemical properties by the cathodic polarization, anodic polarization and cyclic voltammogram. We achieved results that new catalysts showed better performances than existing $La_{1-x}Sr_xCoO_3$, $La_{1-x}Ca_xCoO_3$, ect. catalysts prepared in our lab.

Preparation and Characterization of Doped $Fe_2O_3$ and GaAs Photosemiconductive Electrodes for $CO_2$ Fixation

  • Kim, Il Kwang;Lee, Seong Jae;Kim, Min Su;Jeong, Seung Il;Park, Byung Sun;Kim, Youn Geun
    • Analytical Science and Technology
    • /
    • v.8 no.4
    • /
    • pp.669-674
    • /
    • 1995
  • The preparation and characterization of photosemiconductive electrodes of GaAs and of $Fe_2O_3$ doped with MgO or CaO were investigated. The doped $Fe_2O_3$ photosemiconductive electrodes were prepared from thin films sintered at temperatures from 1,100 to $1,450^{\circ}C$, and rapidly quenched in distilled water. The surfaces of the electrodes containing both corundum structure of $Fe_2O_3$ and spinel structure of $Mg_xFe_{3-x}O_4$ or $Ca_xFe_{3-x}O_4$ were analyzed by X-ray diffraction and scanning electron microscopy. The cathodic and anodic photocurrents on these electrodes indicated a critical doping amount of 5-11 wt. %. The photocurrents were enhanced when GaAs electrodes were treated with methylene violet the anodic photo-currents were temporarial enhanced and changed to the cathodic ptotocurrents after the surface was dryed.

  • PDF

Preparation and Characterization of Porous Filters from Ca(OH)2 and CaCO3 for SO2 Removal in Dry-FGD Process (건식 FGD 공정에서 SO2 제거를 위한 Ca(OH)2 및 CaCO3 원료의 다공성 필터 제조 및 특성)

  • Han, Yo-Seop;Kim, Hyun-Jung;Park, Young-Goo;Park, Jai-Koo
    • Applied Chemistry for Engineering
    • /
    • v.16 no.6
    • /
    • pp.772-777
    • /
    • 2005
  • Porous hydrated lime and limestone filters were prepared by foaming and gelcasting method, and their physical properties were evaluated. Through these analyses, it has been found that with the increased porosity and pore size of the filters, majority of pores in the filters were inter-connected by windows. Also, $SO_2$ removal efficiency for the filters was investigated. As the porosity and the reaction temperature increased, $SO_2$ removal efficiency also increased. Especially, unlike the variation of entrance concentration, the entrance flow rate had great influence on the removal efficiency. In case of the filters with an equal porosity, the hydrated lime filter had superior removal efficiency compared to the limestone filter. From these results, it was shown that the high conversion ratio to CaO from the hydrated lime filter was a result of facilitated formation of $CaSO_4$ by $SO_2$.

An experimental study on preparation of precipitated calcium carbonate using Ca component dissolution characteristics and liquid carbonation by the Industrial byproducts (산업부산물의 Ca 성분 용출 특성 및 액상탄산화 반응을 이용한 침강성 탄산칼슘 제조에 관한 실험적 연구)

  • Lim, Yun-Hui;Lee, Ju-Yeol;Shin, Jae-Ran;Choi, Chang-Sik;Hong, Bum-Ui;Kang, Ho Jong;Park, Byung Hyun
    • Journal of the Korean Applied Science and Technology
    • /
    • v.32 no.1
    • /
    • pp.116-126
    • /
    • 2015
  • The present study utilized a shuttle mechanism of wet chemical absorption using MEA. In addition, industrial by-products containing a large amount of inorganic alkali substances were utilized for wet carbonization process. Chemical pretreatment of industrial by-products extracted calcium ions. ICP result of calcium ion was obtained up to 17,900 ppm(17.9%) by acidic substance. And also, In this work, 94% of recovery rate was obtained using wet MEA absorption process from $CO_2$ flow at the ambient condition. Through the liquid carbonation process, a sludge was fixed with rate of 0.175 mg of $CO_2$ per mg of sludge. It was found from XRD results that the structure of final product was composed of a calcite structure which is general structure of $CaCO_3$.

Preparation of novel NF membrane via interfacial cross-linking polymerization

  • Lehi, Arash Yunessnia;Akbari, Ahmad;Soleimani, Hosna
    • Membrane Water Treatment
    • /
    • v.6 no.3
    • /
    • pp.173-187
    • /
    • 2015
  • The goal of present work is the preparation of a novel positively charged nanofiltration (NF) membrane and its development for the cation removal of aqueous solutions. This NF membrane was fabricated by the surface modification of polysulfone (PSf) ultrafiltration support. The active top-layer was formed by interfacial cross-linking polymerization of poly(ethyleneimine) (PEI) with p-xylylene dichloride (XDC) and then quaternized with methyl iodide to form a perpetually positively charged layer. In order to improve the efficiency of nanofiltration membrane, the concentration of PEI, XDC and methyl iodide solutions, PEI coating and cross-linking time have been optimized. As a result, a high water flux and high $CaCl_2$ rejection (1,000 ppm) was obtained for the composite membrane with values of $18.29L/m^2.h$ and 93.62% at 4 bar and $25^{\circ}C$, respectively. The rejections of NF membrane for different salt solutions followed the order of $Na_2SO_4$ < $MgSO_4$ < NaCl < $CaCl_2$. Molecular weight of cut off (MWCO) was calculated via retaining of PEG solutions with different molecular weights that finally, it revealed the Stokes and hydrodynamic radius of 1.457 and 2.507 nm on the membrane selective layer, respectively. The most efficient positively charged nanofiltration membrane exhibited a $Ni^{2+}$ rejection of 96.26% for industrial wastewater from Shamse Hadaf Co. (Kashan, Iran).