• Journal of the Korean Professional Engineers Association
• /
• v.34 no.2
• /
• pp.167-173
• /
• 2001

Through alkaline hydrothermal activation processes, Na-A type zeolite was synthesized as a single phase withfunnel-glass waste from a television tube factory. The autoclaving was performed in a closed teflon vessel in therange of 80~95"C. The silica-rich solution as a starting material was hydrothermally synthesized with quartz in INNaOH by heating 350"C under the pressure of 1,500 atm. NaA102 was made from NaOH and Al(OH)3 by heating95"c for 2~3 hours and the molar ratios of it were Na20/A1203=1.4 and H20Ha20=8. The equi-dimensional Atype zeolite (1 ~2 U) was formed by the simple mixing of'the silica-rich solution, glass waste and NaA102 for I~3hours-heating at 80"C. The characterization of the reaction product shows Na-A as a single phase. The synthesizedzeolite has cube-dodecahedral form and Ca2+ ion exchange capacity of the Na-A was in the range of 215~220mequivalent/100 g.20mequivalent/100 g.

• Economic and Environmental Geology
• /
• v.34 no.2
• /
• pp.167-173
• /
• 2001

Through alkaline hydrothermal activation processes, Na-A type zeolite was synthesized as a single phase with funnel-glass waste from a television tube factory. The autoclaving was performed in a closed teflon vessel in the range of 80~95$^{\circ}$C. The silica-rich solution as a starting material was hydrothermally synthesized with quartz in IN NaOH by heating 350uC under the pressure of 1,500 atm. $NaAlO_2$ was made from NaOH and Al(OHh by heating 95$^{\circ}$C for 2-3 hours and the molar ratios of it were $Na_2O/Al_2O_3$ = 1.4 and $H_2O/Na_2O$=8. The equi-dimensional A type zeolite (1-2 11) was formed by the simple mixing of the silica-rich solution, glass waste and $NaAlO_23$ for 1-3 hours-heating at $80^{\circ}C$. The characterization of the reaction product shows Na-A as a single phase. The synthesized zeolite has cuba-dodecahedral form and $Ca^{2+}$ ion exchange capacity of the Na-A was in the range of 215-220 mequiva1entilOO g.

• Applied Chemistry for Engineering
• /
• v.4 no.4
• /
• pp.739-745
• /
• 1993

The characteristics of mass transfer in an inorganic ion exchange system where Cs and/or Sr are separated by means of zeolites was investigated. Experimental work to separate Cs or Sr was carried out for Cs-AW300 and CS-AW500 systems in case of Cs whereas for Sr-4A and Sr-13X systems in case of Sr. The experimental conditions were chosen as follows in the batch type separation : temperature $25^{\circ}C$, agitation speed 300rpm, amount of zeolite 4g, volume of solution $0.5{\ell}$, and concentrations of solution 1000ppm, 2000ppm, respectively. As a result, it was found that the mass transfer rate is controlled mainly by the liquid film diffusion. The mass transfer coefficients in the film were found to be in the range of $10^{-4}{\sim}10^{-3}cm/sec$, while the apparent diffusivity inside the particles was found to be in the order of $10^{-8}cm^2/sec$.

• Applied Chemistry for Engineering
• /
• v.30 no.6
• /
• pp.726-730
• /
• 2019

The removal of calcium ions using zeolite to solve problems of the CaCO₃ manufacturing process using cement kiln dust was investigated. To do so, a modified zeolite was employed and experiments were conducted to select the optimal zeolite type considered the binding cation and structure, evaluate the removal performance of calcium ions, the influence of the type and concentration of the modifying solution, and the removal selectivity when K coexists. Among five zeolites, 13X zeolite was found to have the best calcium ion removal performance, and it was confirmed that the removal performance was enhanced when KCl was used as a modifying solution instead of NaCl. This study is expected to be the basis for the solution of carbonation process and high concentration of KCl recovery technology.

• Korean Journal of Crystallography
• /
• v.12 no.2
• /
• pp.97-101
• /
• 2001

Phillipsite-type zeolite powders were synthesized from domestic coal fly ash by hydrothermal reaction with 2.0 M-3.5M NaOH solution at $80^{\circ}C{\sim}120^{\circ}C$ for 24 h. The properties of zeolite were investigated by XRD, SEM and IR spectroscopy. The effects of chemical composition of fly ash, reaction temperature and NaOH concentration on the zeolite synthesis were well appeared on IR spectra. It is found that the $TO_4$(T=Si, Al) tetrahedra have a well ordered structure as the $SiO_2$ content, synthesis temperature and NaOH concentration become high.

• Membrane Journal
• /
• v.16 no.2
• /
• pp.159-166
• /
• 2006

MFI(Mobil Five) structured hydrophobic ZSM-5 zeolite membrane was used for selective pervaporation of trichlorinated organic compounds(trichloromethane, trichloroethane, trichloroethylene) from their aqueous solutions. ZSM-5 zeolite membrane was hydrothermally synthesized on the inside of a porous stainless steel tube by secondary growth employing ZSM-5 seed powders. Separation factors for each binary mixtures were observed $16{\sim}66$ for trichloromethane/water, $3.3{\sim}4.6$ for trichloroethane/water and $1.4{\sim}8$ for trichloroethylene/water at the experimental conditions of the feed mole fraction from 0.0001 to 0.001 with temperature ranged $25{\sim}35^{\circ}C$.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.4
• /
• pp.451-459
• /
• 2021

The purpose of this study is to evaluate the performance of a solidifying agent for recycling the fine powder separated from the nuclear power plant decommissioned concrete as a solidifying agent(SA) for radioactive waste. In order to evaluate the performance of the solidifying agent, a powder simulating the fine powder of waste concrete separated from the dismantled concrete of a nuclear power plant was produced, and the main variables were the type of binder and the replacement ratio of zeolite. The solidifying agent was evaluated for fluidity performance, compressive strength, and leaching resistance to non-radioactive cesium. The compressive strength of SA increased as the zeolite replacement ratio increased, and the SA containing 5% or more of zeolite showed a compressive strength that was 1.4 to 1.7 times higher than the acceptance criteria. The cesium leaching index of all specimens was 6 or higher, satisfying the acceptance criteria, and the leaching index of SA was 1.47~1.63 times higher than that of OPC. In particular, the average leaching index after 28 days of the 5% zeolite-substituted solidifying agent was 9.15, which was improved by about 6.4% compared to OPC, and it was confirmed that the zeolite was effective in improving the leaching resistance to cesium ions by showing stable performance over the entire period.

• Korean Chemical Engineering Research
• /
• v.50 no.3
• /
• pp.442-448
• /
• 2012

The effects of zeolite-type catalysts addition on the thermal decomposition of the PP resin have been studied in a thermal analyzer, a Pyrolyser GC-mass, and a small batch reactor. The zeolite type catalysts tested were natural zeolite, used FCC catalyst, and ZSM-5. As the results of TGA experiments, the pyrolysis starting temperature for PP varied in the range of $330{\sim}360^{\circ}C$ according to the heating rate. Addition of the zeolite type catalysts in the PP resin increased the pyrolysis rate in the order of used FCC catalyst> natural zeolite> ZSM-5 > PP resin. Adding the used FCC catalyst in the PP reduced most effectively the pyrolysis finishing temperature. In the PY-G.C. mass experiments, addition of zeolite type catalysts decreased the molecular weight of pyrolyzed product. In the batch system experiments, the mixing of used FCC catalyst enhanced best the initial yield of fuel oil, but the final yield of fuel oil was 2% higher in the case of mixing of natural zeolite. Also in the carbon number analysis, used FCC catalyst was the most useful one in this experiments for fuel oil.

• Applied Chemistry for Engineering
• /
• v.30 no.1
• /
• pp.54-61
• /
• 2019

In this study, a magnetic adsorbent was synthesized by growing ferrite nanoparticles substituted with metals (Me = Co, Mn, Ni) on zeolite 4A for the efficient separation of waste adsorbents present in the solution after the adsorption of Cu(II). The metal ferrite grown on the surface of zeolite was prepared by solvothermal synthesis. Characteristics of the magnetic adsorbent were analyzed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and physical property measurement system (PPMS). The saturation magnetization of the A type zeolite coated with Co-ferrite (CFZC) was the highest at 5 emu/g and the Cu(II) adsorption performance was also excellent. The adsorption results of Cu(II) on CFZC were well fitted by the Langmuir model at 298 K. Also, the adsorption of Cu(II) on CFZC follows a pseudo-second order kinetic. The Gibbs free energy values (${\Delta}G^0$) ranging from -4.63 to -5.21 kJ/mol indicates that the Cu(II) adsorption is spontaneous in the temeprature range between 298 and 313 K.

• Applied Chemistry for Engineering
• /
• v.16 no.1
• /
• pp.123-130
• /
• 2005

Zeolite X adsorbents with large surface area were prepared for using oxygen PSA adsorbent. Selective adsorption performance of nitrogen on the synthesized zeolite X adsorbent was improved by the cation exchange of adsorbent. The zeolite X which had over $650m^2/g$ surface area was synthesized at the conditions of $SiO_2\;:\;Na_2O\;:\;H_2O\;:\;Al_2O_3$ = 2.5 : 3.5 : 150 : 1 mole ratio, $98^{\circ}C$ temperature and 18 h synthesized time in 50 L reactor. The metal ions Li, Ag, Ca, Br, Sr, etc. were investigated for ion exchange with zeolite X. Ag ion was showed the highest ion exchange rate among these metal ions and all metal ions were exchanged with Na ion at equivalent rate. Compared with the NaX adsorbent, the ion exchanged zeolite X adsorbent remarkably improved its adsorption performance of nitrogen at the conditions of $10{\sim}40^{\circ}C$ temperature and 0~9 atm pressure. At an equilibrium pressure under 0.5 atm, adsorption performance of nitrogen on the ion exchanged zeolite adsorbent increased in the order of Ag > Li > Ca > Sr> Ba > K, whereas at an equilibrium pressure over 1 atm showed in the order of Li > Ag > Ca > Sr > Ba > K. Nitrogen/oxygen separation factor of Li ion exchanged zeolite X adsorbent was 13.023 at the partial pressure of nitrogen/oxygen gas mixture similar to air and $20^{\circ}C$ adsorption temperature.