• Environmental Engineering Research
• /
• v.24 no.2
• /
• pp.246-253
• /
• 2019

This study was conducted to explore the optimum proportion of zeolite and zeolite-kaolin as additives to cement clinker and gypsum samples, while maintaining the strength properties of produced environmentally sustainable cements. According to the British standard method, zeolite was added to cement clinker in proportions of 5-12% and 10-12% by weight, respectively, in the preparation of samples of zeolite-containing cement and zeolite-kaolin-based cement. Kaolin was used as a second additive as 10-20% of the total weight. The compressive strength tests were performed on base cement samples according to a standard procedure given in ASTM C109 Compressive Strength of Hydraulic Cement. These values were compared with those of the reference sample and the Omani allowable limits. The results indicated that the best compressive strength values were obtained with 88% cement clinker, 5% gypsum, and 7% zeolite for the zeolite-containing cement. Quantities of 70% cement clinker, 5% gypsum, 10% zeolite, and 15% kaolin gave the best results for zeolite-kaolin-based cement, resulting in a substitution of than 25% cement clinker. The study concluded that the partial cement clinker replacement using zeolite/kaolin combination may have a great influence on the reduction of $CO_2$ emission and energy saving in cement manufacturing.

• Journal of Environmental Science International
• /
• v.12 no.10
• /
• pp.1061-1069
• /
• 2003

The adsorption behaviors of strontium and cesium ions on fly ash, natural zeolites, and zeolites synthesized from fly ash were investigated. The zeolites synthesized from fly ash had greater adsorption capabilities for strontium and cesium ions than the original fly ash and natural zeolites. The maximum adsorption capacity of synthetic zeolite for strontium and cesium ions was 100 and 154 mg/g, respectively, It was found that the Freundlich isotherm model could fit the adsorption isotherm. The distribution coefficients (K$\_$d/) for strontium and cesium ions were also calculated from the adsorption isotherm data, The distribution coefficients decreased with increasing equilibrium concentration of strontium and cesium ions in solution. By studying the removal of cesium and strontium ions in the presence of calcium, magnesium, sodium, potassium, sulfate, nitrate, nitrite, and EDTA (in the range of 0.01 - 5 mM) it was found that these coexistence ions competed for the same adsorption sites with strontium and cesium ions.

• Journal of Korean Society on Water Environment
• /
• v.28 no.5
• /
• pp.723-728
• /
• 2012

In this study, zeolites were synthesized by a fusion and a hydrothermal methods using a coal fly ash and a waste catalyst. The recovery performance of metal ions on the structure property of synthetic zeolites was evaluated as comparing the adsorption kinetics (Lagergen 2nd order model) and isotherm (Langmuir model) of $Co^{2+},\;Ni^{2+}$, and $Cu^{2+}$ ions. The synthetic zeolites (Z-C1 and Z-W5) were similarly assigned to XRD peaks in a reagent grade Na-A zeolite (Z-WK : $Na_{12}Al_{12}Si_{12}O_{48}\;27.4H_2O$). Adsorption rates of Z-W5 and Z-C1 were in the order of $Cu^{2+}\;>\;Co^{2+}\;>\;Ni^{2+}\;and\;Ni^{2+}\;>\;Cu^{2+}\;>\;Co^{2+}$, respectively. They had influenced upon structure properties of zeolite. Selectivities of metal ions and maximum equilibrium adsorption capacities, $q_{max}$, in Z-C1 and Z-W5 were in the order of $Ni^{2+}$ (127.9 mg/g) > $Cu^{2+}$ (94.7 mg/g) > $Co^{2+}$ (82.6 mg/g) and $Cu^{2+}$ (141.3 mg/g) > $Co^{2+}$ (122.2 mg/g) > $Ni^{2+}$ (87.6 mg/g), respectively. The results show that the synthetic zeolites, Z-C1 and Z-W5, are able to recover metal ions selectively in wastewater.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.04a
• /
• pp.7-10
• /
• 2001

Adsorption of the pesticides (phosphamidon, fenitrothion, triadimefon and diniconazole) in natural zeolite (CL $I_{N}$) and several synthetic zeolites was incestigated. The pesticides were not adsorbed on zeolites (Na-Pl, SOD, ANA, JBW and CAN) synthesized from Jeju scoria. The distribution coefficient ( $K_{D}$) and the Freundlich constant ( $K_{F}$) decreased in the following sequences. FC $C_{W}$ (waste catalytic cracking catalyst)>FA $U_{F}$ (FAU Synthesized from coal fly ash)>(FAU+Na-Pl)$_{SF}$ (the mixture of FAU and Na-Pl synthesized from the ratio of Jeju scoria 6 to coal fly ash 4 by weight)>CL $I_{N}$ among the zeolites; diniconazole>fenitrothion> triadimefon>phosphamidon. As the temperature was increased, the amount of pesticide adsorbed per unit mass of zeolite increased for FC $C_{W}$, FA $U_{F}$ and (FAU+Na-Pl)$_{SF}$ but it decreased for CL $I_{N}$, for all the pesticides used in this study. It was independent of pH for phosphamidon, fenitrothion and triadimefon, but decresed as pH was increased for all the zeolites used in this study.y.udy.y.y.y.y.y.y.

• Journal of the Mineralogical Society of Korea
• /
• v.5 no.2
• /
• pp.61-71
• /
• 1992

Through the low-temperature(60-150${\circ}C$) hydrothermal treatment of perlite with the alkaline solution at various NaOH concentrations, the mode of volcanic glass alteration and resultant zeolite formation were investigated in a closed system. At a temperature of 80${\circ}C$ and alkalinities of pH range 8 to 12, corresponding to the natural environments of diagenetic zeolite formation, only weak dissolution of perlitic glass occurs without zeolite formation despite the residence time of 100 days. Activities of Si and Al increase progressively, as a consequence of increasing pH, whereas activity ratios of Si/Al decrease. Zeolites were synthesized from perlite in the alkaline solution at above 0.1M NaOH concentrations. Below the temperature of 100${\circ}C$ Na-P was mainly formed, whereas analcime was the dominant zeolite at the temperature range of 100-150${\circ}C$. During Na-P synthesis chabazite and Na-X were also formed as by-products in case of lower proportion of solution/sample(<10ml/g) and higher NaOH concentraion (>3M), respectively. The alteration modes of perlite in the zeolite synthesis reflect that the formation of synthetic zeolites occurs as an incongruent dissolution likely with the diagenetic formation of natural zeolites from volcanic glass. Considering much difference in reaction kinetics between natural and synthetic systems, however, the evaluated synthetic conditions in these experiments were not directly applicable to the natural diagenetic system.

• Applied Chemistry for Engineering
• /
• v.28 no.6
• /
• pp.685-690
• /
• 2017

Ammonia is a useful substance which is widely used in various industries. It is generally released by the decomposition of agricultural wastes and known to have toxic effects on human beings. Due to the common usage, it is possible to cause water pollution through either direct or indirect leakage. Such cases, it is preferable to use the adsorption capacity of zeolite to rapidly remove ammonium ions, but it is not sufficiently removed by the adsorption only. In this paper, the removal efficiency of ammonium ion through both the adsorption capacities of commercial synthetic zeolites and the biological mechanism of microorganisms were compared. In addition, microorganisms were immobilized on the zeolite in order to enhance the removal efficiency by applying a chemo-biological process. As a result, the standard commercial zeolite showed 67~81% of the removal efficiency in 2~4 hours at a 100 ppm concentration of ammonium, whereas the selected microorganism Klebsiella pneumoniae subsp. Pneumoniae showed up to 97% within 8 hours. When the microorganism was immobilized on the zeolite, the highest removal efficiency of approximately 98.5% were observed within 8 hours.

• Korean Journal of Materials Research
• /
• v.5 no.8
• /
• pp.1035-1039
• /
• 1995

Synthetic zeolite was prepared by using of natural bentonite from Kampo area and the application of detergent builder was investigated. The optimum synthetic condition was SiO$_2$/Al$_2$O$_3$= 2, Na$_2$O/A1$_2$O$_3$=1, H$_2$O/A1$_2$O$_3$=30 at 90$^{\circ}C$ for 3hr and it was found by XRD analysis that the zeolite synthesized under this condition was type A. When the zeolite A synthesized under the optimum condition was contacted with 40$^{\circ}$Dh CaCl$_2$solution at 30$^{\circ}C$ for 15min, the cation exchange capacity was 264.9mg CaO/g-zeolite. And the whiteness of the sample was 89% and the mean particle size was 9.95$\mu\textrm{m}$.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.9 no.1
• /
• pp.6-13
• /
• 1999

NaX zeolite crystal were grown from seed elements of synthetic NaX(2~3$\mu\textrm{m}$) Powder in a mother liquor having an approximate reactant composition ${4.12{Na}_{2}O{\cdot}{Al}_{2}{O}_{3}{\cdot}3.5{SiO}_{2}{\cdot}593{H}_{2}O$.The result was that crystallization time of NaX zeolite was reduced with adding seed materials to the initial mixture and crystal size was reduced . but with increasing crystallization time, NaX zeolite. In this study, We investigated detailed factors which NaX crystal has been determined by a combination of SEM, XRD, FT-IR, and BET.

• Applied Chemistry for Engineering
• /
• v.9 no.5
• /
• pp.615-618
• /
• 1998

The zeolite crystals were synthesized by hydrogel process into the pore of activated carbon. The effect of activated carbon in the course of the crystallization of zeolite was investigated. The phenomena of impregnation of zeolite crystals into the pore of the activated carbon were also examined. The results show that in case of the addition of 5% of activated carbon to the aluminosilicate gel including the mole composition of zeolite A, zeolite A was purely synthesized without the existence of other type of zeolite. However, in case of the addition of 20% of activated carbon, zeolite X was purely synthesized. In the pore mouth and internal of activated carbon, zeolite crystals having the size under $1{\mu}m$ was observed. From the results of the pore size and particle size distributions, it was confirmed that the synthetic sample was the composite material impregnated by the zeolite crystals into the pore of activated carbon, not the simple mixture of zeolite and activated carbon.

• Journal of Environmental Science International
• /
• v.1 no.2
• /
• pp.167-175
• /
• 1992

This study was conducted for an efficient utilization of waste fly ash obtained from the power plant. Fly ash was used for synthesizing zeolite. Na-Pl zeolite could be easily synthesized from waste fly ash and showed the potential to remove heavy metal ions. The synthetic zeolite showed good adsorption property for heavy metal much better than raw fly ash and natural zeolites. Na-Pl exhibited the high adsorption efficiency with a maximum value of 260 Pb mg/g and strong affinity for Pb2+ ion. The metal ion selectivity of Na-Pl was determined in a decreasing order : $Pb^{2+}$>$Cd^{2+}$>$Cu^{2+}$+>$Zn^{2+}$>$Fe^{3+}$