• Title/Summary/Keyword: Co-phosphate

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Synthesis and application of zirconium phosphate mesoporous coordination polymer for effective removal of Co(II) from aqueous solutions

  • Yang Zeng;Guoyuan Yuan;Tu Lan;Feize Li;Jijun Yang;Jiali Liao;Yuanyou Yang;Ning Liu
    • Nuclear Engineering and Technology
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    • v.54 no.11
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    • pp.4013-4021
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    • 2022
  • A kind of zirconium phosphate mesoporous coordination polymer Zr-EDTMPA was successfully synthesized and characterized using XRD, FTIR, TGA, EA, SEM-EDS, and N2 sorption-desorption measurements. The prepared Zr-EDTMPA was first employed for the removal of Co(II) from an aqueous solution, and the effects of pH, contact time, temperature, initial Co(II) concentration, reusability, and sorption mechanism were systematically investigated. The results showed that the Zr-EDTMPA is a zirconium phosphate complex formed by the coordination of EDTMPA to Zr in a molar ratio of 1:1. The sorption of Co(II) by Zr-EDTMPA was a pH-dependent, spontaneous and endothermic process, which was better fitted to the pseudo-second-order kinetic model and Langmuir isotherm model. The Zr-EDTMPA was demonstrated to have excellent reusability and presented a high sorption capacity of 73.0 mg·g-1 for Co(II) at pH 8.0. The sorption mechanism was mainly attributed to the strong coordination between cobalt and the untapped hydroxyl functional groups on Zr-EDTMPA, which was confirmed by XPS spectra. Therefore, as a candidate sorbent with high sorption capacity and excellent reusability, Zr-EDTMPA has a great potential for the removal of Co(II) from aqueous solutions.

Formation of Hydroxyapatite in Portland Cement Paste

  • Chung, Chul-Woo;Lee, Jae-Yong;Kim, Ji-Hyun
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.1
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    • pp.68-75
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    • 2014
  • In order to increase the integrity of the wellbore which is used to prevent the leakage of supercritical $CO_2$, it is necessary to develop a concrete that is strongly resistant to carbonation. In an environment where the concentration of $CO_2$ is exceptionally high, $Ca^{2+}$ ion concentration in pore solution of Portland cement concrete will drop significantly due to the rapid consumption of calcium hydroxide, which decreases the stability of the calcium silicate hydrate. In this research, calcium phosphates were used to modify Portland cement system in order to produce hydroxyapatite, a hydration product that is strongly resistant to carbonation under such an environment. According to the experimental results, calcium phosphates reacted with Portland cement to form hydroxyapatite. The formation of hydroxyapatite was verified using X-ray diffraction analyses with selective extraction techniques. When using dicalcium phosphate dihydrate and tricalcium phosphate, the 28-day compressive strength was lower than that of plain cement paste. However, the specimen with monocalcium phosphate monohydrate showed equivalent strength to that of plain cement paste.

Fabrication of Porous Calcium Phosphate by Using a Pre-Form of Nature Material (자연물의 미세구조를 활용한 다공성 인산칼슘 제조)

  • Lee, Sang-Jin;Lee, Hoon-Cheol
    • Journal of the Korean Ceramic Society
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    • v.47 no.3
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    • pp.244-248
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    • 2010
  • Porous calcium phosphates were successfully fabricated by using a cuttlefish bone. The cuttlefish bone, which is composed of $CaCO_3$, showed a special porous microstructure containing uniform-sized voids. In this study, the pre-forms infiltrated distilled phosphoric acid were sintered at $1200^{\circ}C$ in an air atmosphere. The porous microstructure of the pre-forms was kept their original pattern after sintering with a synthesis of calcium phosphate. The obtained porous calcium phosphate, sintered at $1200^{\circ}C$ for 3 h at 17% concentration of phosphoric acid, showed uniform open pores of 150 ${\mu}m$ in size and $\beta$-TCP phase in the XRD patterns. Above 16% concentration, CaO phase, derived from the decomposition of $CaCO_3$, decreased gradually in the sintered samples, and the measured Ca/P ratios of the samples prepared from 16% and 18% concentration were 1.67 and 1.43, which are close to stoichiometric HA (1.66) and $\beta$-TCP (1.50).

Development of Lyocell-Based Graphite Fabric for Aerospace (항공우주용 리오셀계 흑연화 직물 개발)

  • Park, Gil-Young;Kim, Nam-Kyu;Kim, Yun-Chul;Seo, Sang-Kyu;Chung, Yong-Sik
    • Journal of the Korean Society of Propulsion Engineers
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    • v.25 no.4
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    • pp.36-42
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    • 2021
  • In this study, the impregnation of Lyocell fabrics was performed using phosphoric acid, ammonium phosphate, diammonium hydrogen, triammonium phosphate as phosphorus flame retardant, to fabricate continuous graphite fabrics using lyocell fiber. The physical and chemical structure changes were investigated by thermogravimetric, Fourier-transform infrared spectroscopy, C-nuclear magnetic resonance, X-ray diffraction, and weight analyses, By analyzing the thermal behavior of phosphorus flame retardant, conditions for the temperature, gas, and residual time of the pyrolysis process were set. Graphite fabrics with a tensile strength of 1,007.19±11.47 N/5 cm and yield of 25.3% were fabricated using continuous pyrolysis, carbonization and graphitization process.

Assessment of the Struvite Crystallization Process for Phosphate Removal and Recovery from a Sludge Treatment System of a Domestic Wastewater Treatment Plant (하수처리장 슬러지처리 계통에서의 인 제거 및 회수를 위한 Struvite 결정화 공정 적용성 평가)

  • Baek, Seung Ryong;Lee, Byung Joon
    • Journal of Korean Society of Environmental Engineers
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    • v.39 no.8
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    • pp.462-469
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    • 2017
  • Eutrophication and shortage of phosphate ore raise the necessity of phosphate removal and recovery from wastewater treatment plants. Especially, a sludge treatment system containing highly concentrated phosphate should be targeted for phosphate removal and recovery. This study thus aimed to evaluate the capability of the struvite crystallization process for phosphate removal and recovery from a sludge treatment system of a wastewater treatment plant. Analysis on phosphate concentrations and masses in the sludge treatment system revealed that digested sludge and centrate have phosphate concentrations and masses, high enough to adopt the struvite crystallization process. Chemical equilibrium modeling indicated that the struvite crystallization reaction substantially occurred with pH higher than 8 and $Mg^{2+}$ concentration 1.2 times higher than its theoretical requirement. A series of batch tests with digested sludge and centrate indicated that the phosphate removal reaction by struvite crystallization followed a first-order kinetics and reached over 80% removal efficiency at equilibrium. Aeration in the batch tests was found to purge $CO_2$ in sludge or centrate and increase pH up to 8.7, without adding NaOH. Thus, we concluded that the struvite crystallization process could be an efficient and economical process for phosphate removal and recovery from a wastewater treatment plant.

A STUDY ON THE RETENTION OF CAST POST (주조 포스트의 유지력에 관한 연구)

  • Kim Sung-Hoon;Cho Hye-Won;Jin Tai-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • v.31 no.4
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    • pp.461-467
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    • 1993
  • The purpose of this study was to evaluate the effects of method for construction of cast post and type of dental cement on the retention of cast post. The wax patterns or Duralay resin patterns were used for construction of cast post. The dental cements used in this study were zinc phosphate cement(Fleck's zinc cement, Mizzy INc., U.S.A.), glass ionomer cement(Fuji I, G-C Co., Japan), and resin cement(Panavia-EX, Kuraray Co., Japan) and the retention of cast post was measured with Instron Universal Test Machine(Instron Engineering Co., U.S.A.). The obtained results were as follows : 1. The tensile bond strength of cast posts made by Duralay resin patterns revealed 39.13(kg) with Panavia-EX, 46.40(kg) with phosphate cement, and 37.78(kg) with glass ionomer cement. 2. The tensile bond strength of cast posts made by wax patterns revealed 39.25(kg) with Panavia, EX, 44.12(kg) with phosphate cement, and 40.23(kg) with glass ionomer cement. 3. The tensile bond strength of cast posts made by Duralay resin patterns or wax patterns were not affected by the type of dental cements(P>0.05).

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Effects of alkali species and concentration on the size distribution of the co-precipitated magnetite particles used for phosphate adsorption (인 흡착용 마그네타이트 합성 시 알칼리 종류 및 농도가 공침 입자크기에 미치는 영향)

  • Lee, Minhyeong;Doliente, Jonica Ella;Nam, Haiuk;Kim, Yunjung;Choi, Younggyun
    • Journal of Korean Society of Water and Wastewater
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    • v.30 no.4
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    • pp.409-415
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    • 2016
  • Magnetite particles were synthesized by co-precipitation of water-soluble 밀 스케일-derived precursor by various concentrations of (0.5, 0.67, 1, 2 N) NaOH and (0.6, 0.8, 1.2, 2.4 N) $NH_4OH$. It is theoretically known that as the concentration of the alkaline additive used in iron oxide synthesis increases, the particle size distribution of that iron oxide decreases. This trend was observed in both kind of alkaline additive used, NaOH and $NH_4OH$. In addition, the magnetite synthesized in NaOH showed a relatively smaller particle size distribution than magnetite synthesized in $NH_4OH$. Crystalline phase of the synthesized magnetite were determined by X-ray diffraction spectroscopy(XRD). The particles were then used as an adsorbent for phosphate(P) removal. Phosphorus adsorption was found to be more efficient in NaOH-based synthesized magnetite than the $NH_4OH$-based magnetite.

Combustion-Retardation Properties of Pinus rigida Treated with Ammonium Salts (암모늄염으로 처리된 리기다 소나무의 난연성)

  • Chung, Yeong-Jin;Jin, Eui
    • Applied Chemistry for Engineering
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    • v.21 no.6
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    • pp.627-631
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    • 2010
  • This study was performed to test the combustion-retardation properties of Pinus rigida-based materials by the treatment of ammonium salts. Pinus rigida plate was soaked by the treatment with three 20 wt% ammonium salt solutions consisting ammonium sulfate (AMSF), monoammonium phosphate (MAPP), and diammonium phosphate (DAPP), respectively, at the room temperature. After the drying specimen treated with chemicals, combustion properties were examined by the cone calorimeter (ISO 5660-1). When the ammonium salts were used as the retardant for Pinus rigida, the flame retardancy improved due to the treated ammonium salts in the virgin Pinus rigida. However the specimen shows increasing CO over virgin Pinus rigida and It is supposed that toxicities depend on extents. Also, the specimen with ammonium sulfate showed both the lower total smoke release (TSR) and lower total smoke production (TSP) than those of virgin plate. Among the specimens, the sample treated with diammonium phosphate showed a strong inhibitory effect of combustion.

Synergistic Phosphate Solubilization by Burkholderia anthina and Aspergillus awamori

  • Walpola, Buddhi Charana;Jang, Hyo-Ju;Yoon, Min-Ho
    • Korean Journal of Soil Science and Fertilizer
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    • v.46 no.2
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    • pp.117-121
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    • 2013
  • Single or co-inoculation of phosphate solubilizing bacterial and fungal strains (Burkholderia anthina and Aspergillus awamori respectively) was performed separately to assess their synergistic and antagonistic interactions and the potential to be used as bio-inoculants. Co-inoculation was found to release the highest content of soluble phosphorus (1253 ${\mu}g\;ml^{-1}$) into the medium, followed by single inoculation of fungal strain (1214 ${\mu}g\;ml^{-1}$) and bacterial strain (997 ${\mu}g\;ml^{-1}$). However, there was no significant difference between single inoculation of fungal strain and co-inoculation of fungal and bacterial strain in terms of the phosphorous release. The highest pH reduction, organic acid production and glucose consumption were observed in the sole A. awamori inoculated culture medium. According to the plant growth promotion bioassays, co-inoculation of the microbial strains resulted in 21% and 43% higher shoot and root growth of the mung bean seedlings respectively as compared to the respective controls. Therefore, co-inoculation of B. anthina and A. awamori showed better performance in stimulating plant growth than that in inoculation of each strain alone. However, assessment period of the present study being short, we recommend in engaging further experimentation under field conditions in order to test the suitability of the strains to be used as bio-inoculants.

Effects of Phosphates on the Growth of Lactic Acid Bacteria (인산(燐酸) 염(鹽)이 유산균(乳酸菌)의 생장(生長)에 미치는 영향(影響))

  • Yu, Tae-Jong;Kim, Il-Hwan
    • Korean Journal of Food Science and Technology
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    • v.11 no.3
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    • pp.200-205
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    • 1979
  • Effects of monosodium phosphate, disodium phosphate, trisodium phosphate, ${\alpha}-polygel$, sodium ultrametaphosphate and sodium tripolyphosphate on the growth of bacteria, pH and acidity in single culture of Lactobacillus bulgaricus and mixed-culture of Lactobacillus bulgaricus and Streptococcus thermophilus were investigated. Phosphates exerted definite effect in enhancing the growth of the bacteria and acidity of the fermented milk. For the single-culture of Lactobacillus bulgaricus monosodium phosphate and sodium tripolyphosphate were most effective in terms of bacterial growth and acidity, whereas for the mixed-culture of Lactobacillus bulgaricus and Streptococcus thermophilus monosodium phosphate and disodium phosphate showed the best results. In the presence of the phosphates, particularly of trisodium phosphate, the decrease of viable count of bacteria in fermented milk during storage was reduced significantly. The stability of the fermented milk prepared with the mixed-culture of Lactobacillus bulgaricus and Streptococcus thermophilus was improved by the addition of phosphates, particularly of monosodium phosphate.

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