Preparation of a hydroxyapatite film and its application in the removal and regeneration of aqueous cations

Sugiyama, Shigeru; Shimizu, Yuka; Manabe, Tomoyuki; Nakagawa, Keizo; Sotowa, Ken‐Ichiro

doi:10.1016/j.jcis.2009.01.001

Cited by 21 publications

(7 citation statements)

References 18 publications

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“…Precursor sols of CaHAp, Pd-MgVO and MgVO, which were used for the preparation of a catalyst bed in the microreactor, were prepared as shown in our previous papers (Sugiyama et al, 2008b(Sugiyama et al, , 2009). The microreactor used in the present study consisted of a T union (quartz tube, K ϭ 6 mm) and electrodes (stainless wire, K ϭ 0.3 mm) connected to Pt wire (K ϭ 0.1 mm) ( Figure 1) (Sotowa et al, 2008).…”

Section: Methodsmentioning

confidence: 99%

Application of a Microreactor in the Oxidative Dehydrogenation of Propane to Propylene on Calcium Hydroxyapatite and Magnesium ortho-Vanadate Doped and Undoped with Palladium

Sugiyama

Sugimoto

Ozaki

et al. 2010

J. Chem. Eng. Japan / JCEJ

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IntroductionPropylene mainly obtained by naphtha cracking is an important raw material for the petrochemical industry. Since the demand of propylene derivatives has recently exceeded that of ethylene, a lack of propylene is a concern for the middle to long term (Suwa, 2004). Therefore, the development of another technology for the production of propylene is desired. The oxidative dehydrogenation of propane on solid catalysts is one of the most attractive reactions for the production of propylene. In our laboratory, calcium hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ; CaHAp) and palladium-doped magnesium ortho-vanadate (Mg 3 V 2 O 8 doped with Pd; PdMgVO) have shown relatively greater catalytic activity for the oxidative dehydrogenation of propane to propylene, while magnesium ortho-vanadate (MgVO) itself has shown rather low activity (Sugiyama et al., 2008a(Sugiyama et al., , 2008b. Although Pd-MgVO in particular has shown great catalytic activity during the oxidative dehydrogenation of propane, a deep oxidation of propylene to CO and CO 2 (COx) could not be avoided when using a typical fixed-bed continuous-flow reactor. Therefore, a different reactor system for the suppression of deep oxidation had to be developed.In the present study, a microreactor under steadystate operation was employed to suppress the deep oxidation of propylene to COx as an enhancement of the selectivity to propylene. As a catalyst, CaHAp, Pd-MgVO and MgVO were employed. We also examined the effect of unsteady-state operation, defined by heating (on) and cooling (off) of the power supply, on oxidative dehydrogenation. Furthermore, the catalytic activity of the microreactor was compared with a typical fixed-bed contin- A microreactor was employed for the oxidative dehydrogenation of propane to propylene in order to suppress a deep oxidation of the resultant propylene to CO and CO 2 . Magnesium ortho-vanadate, doped and undoped with palladium, and calcium hydroxyapatite, were used as catalysts while the reaction temperature was controlled by steady-and unsteady-state conditions. The enhancement of the selectivity to propylene was the most advantageous effect from using the microreactor, and it occurred when calcium hydroxyapatite was used under an unsteady-state. For example, the selectivity to propylene was 0 and 73.0% using a fixed-bed continuous-flow reactor and the microreactor, respectively, under almost identical propane conversion of 3.1 and 3.2%, respectively. The advantageous effect was also achieved, although to a lesser degree, when magnesium ortho-vanadate was used undoped with palladium under both steady-and unsteady-state conditions. However these advantageous effects of the microreactor were not observed with magnesium ortho-vanadate doped with palladium. With regard to the selectivity to propylene, the redox nature of the catalysts seemed to influence the performance of the microreactor. Application of a Microreactor in the Oxidative 575

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Section: Methodsmentioning

confidence: 99%

Application of a Microreactor in the Oxidative Dehydrogenation of Propane to Propylene on Calcium Hydroxyapatite and Magnesium ortho-Vanadate Doped and Undoped with Palladium

Sugiyama

Sugimoto

Ozaki

et al. 2010

J. Chem. Eng. Japan / JCEJ

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“…It is generally accepted that the removal of aqueous cation (Fe 3+ in this study) using CaHAp proceeds through the dissolution-precipitation mechanism. 7 In the mechanism, CaHAp dissolves to form phosphate anions and Ca…”

Section: Removal Of Fe 3+ Using Cahap From the Solution Obtained Aftementioning

confidence: 99%

“…The solution pH in FIGURERS 4 and 5 was 2.5, while that in 2 , the regeneration of CaHAp is possible. 7,8 In some cases, the regeneration results in the formation of calcium phosphate species rather than CaHAp. 7,8 The regenerated CaHAp or calcium phosphate species can be reused for the removal of aqueous cationic metals.…”

Section: +mentioning

confidence: 99%

“…7,8 In some cases, the regeneration results in the formation of calcium phosphate species rather than CaHAp. 7,8 The regenerated CaHAp or calcium phosphate species can be reused for the removal of aqueous cationic metals. 9,10 Therefore the combination of the wet-processing method for the slag and the enrichment of phosphate of the solution obtained after the wet-processing using CaAHp should be one of the most possible candidates for the production and the enrichment of phosphate from the slag.…”

Section: +mentioning

confidence: 99%

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Recovery and Enrichment of Aqueous Phosphate From the Slag Released by a Chemical Factory

Sugiyama

Hayashi

Shinomiya

et al. 2012

Phosphorus Research Bulletin

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: The elution behaviors of phosphate from the slag released by a chemical factory using various eluates were examined. Since this slag was covered with organic species, two pretreatment methods for the slag -one the calcination of the slag and the other the trituration of the slag -were employed to strip away the organic species from the slag. Since the elution rate from the pre-triturated slag was evidently greater than that from the pre-calcined slag, the elution behavior of the former was mainly examined in the present study. For the efficient elution of phosphate from the slag, the use of 1M HNO 3 as an eluate and 30 min of trituration time were suitable. Unfortunately, together with the elution of phosphate from the slag, some cationic species were simultaneously eluted. In the present study, the removal behavior of iron cation, which was a main contaminant in the slag, using calcium hydroxyapatite (CaHAp) was also examined. Even when the solution obtained by the elution of the slag was employed for the removal of Fe 3+ using CaHAp, the Fe 3+ could be favorably removed from the solution. Results from the present study suggests that unused phosphate in slag is a potential source of raw material for rare phosphorus.

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“…Among all of these treatment processes, the adsorption using suitable adsorbents should be considered one of the most effective and economical methods in terms of and the simplicity of design and easiness of operation [1,12,13], which even can be used to applications in the purification of drinking water. Great efforts have been contributed to the development of new adsorbents like activated carbon, chelating resin, hydroxyapatite, silica gel, zeolite, clay, goethite, modified mineral adsorbent, and other functional polymers each has its merits and limitations in practice [14][15][16][17]. Nonetheless, the cost and regeneration of adsorbents are the key factors influencing their application in practice, especially for the treatment of large volume of wastewater.…”

Section: Introductionmentioning

confidence: 99%

Preparation and adsorption performance of a novel bipolar PS-EDTA resin in aqueous phase

Yang

Wang

et al. 2010

Journal of Hazardous Materials

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Preparation of a hydroxyapatite film and its application in the removal and regeneration of aqueous cations

Cited by 21 publications

References 18 publications

Application of a Microreactor in the Oxidative Dehydrogenation of Propane to Propylene on Calcium Hydroxyapatite and Magnesium ortho-Vanadate Doped and Undoped with Palladium

Application of a Microreactor in the Oxidative Dehydrogenation of Propane to Propylene on Calcium Hydroxyapatite and Magnesium ortho-Vanadate Doped and Undoped with Palladium

Recovery and Enrichment of Aqueous Phosphate From the Slag Released by a Chemical Factory

Preparation and adsorption performance of a novel bipolar PS-EDTA resin in aqueous phase

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