水热法合成白磷钙石

doi:10.15541/jim20160704

摘要/Abstract

摘要：

以CaO、Mg(NO₃)₂和H₃PO₄为原料, 通过水热法合成白磷钙石。采用X射线衍射(XRD)、场发射扫描电子显微镜(SEM)、热分析(TG-DTA)和X射线荧光光谱(XRF)进行了分析表征。结果表明, 随着初始溶液中Mg/(Ca+Mg)摩尔比的增加, 白磷钙石的结晶行为有显著不同: 形貌由六方板状晶体(直径30~50 μm)向球形聚集体(直径3~5 μm)转变, 晶胞参数a和c值则逐渐减小。初始溶液中Mg/(Ca+Mg)增加, 产物中的Mg/(Ca+Mg)含量也逐渐增加, Mg/ (Ca+Mg)的最高值为13.6%。在实验条件下, 白磷钙石的成核与结晶过程在2 h之内基本完成。白磷钙石Ca₁₈Mg₂H₂(PO₄)₁₄在680~950℃之间脱去结构水, 转变为Ca₁₈Mg₂(PO₄)₁₂P₂O₇。

关键词: 水热法, 合成白磷钙石, 六方板状晶体, 球形聚集体

Abstract:

Whitlockite was firstly synthesized by a hydrothermal method using CaO, Mg(NO₃)₂and H₃PO₄ as starting materials and then characterized by X-ray diffraction, scanning electron morphology, thermal analysis, and X-ray fluorescence. The variation of molar ratio of Mg/(Ca+Mg) in the precursor solution resulted in different crystallization behaviors of whitlockite during hydrothermal treatment. With the increase of the molar ratio of Mg/(Ca+Mg), crystal morphologies of products varied from hexagonal plate (about 30-50 μm) to spheres (about 3-5 μm) and cell parameters of a and c values decreased gradually. Meanwhile, the content of Mg/(Ca+Mg) in the products increased gradually and reached a high value of 13.6%. It was found that the nucleation and growth of whitlockite were almost completed within 2 h. Ca₁₈Mg₂H₂(PO₄)₁₄ was transformed to Ca₁₈Mg₂(PO₄)₁₂P₂O₇ after calcination at temperature ranging from 680℃ to 950℃ due to the dehydration reaction.

Key words: hydrothermal method, synthetic whitlockite, hexagonal plate-like crystal, microsphere

中图分类号:

TB321

李国昌, 王萍, 刘长波. 水热法合成白磷钙石[J]. 无机材料学报, 2017, 32(11): 1128-1132.

LI Guo-Chang, WANG Ping, LIU Chang-Bo. Hydrothermal Synthesis of Whitlockite[J]. Journal of Inorganic Materials, 2017, 32(11): 1128-1132.

图/表 9

图1 不同Mg/(Ca+Mg)样品的XRD图谱

Fig. 1 XRD patterns of different Mg/(Ca+Mg) samples (180℃, 6 h)(a) Mg0.1; (b) Mg0.2; (c) Mg0.3; (d) Mg0.4; (e) Mg0.5

表1 根据XRD数据精修的晶胞参数

Table 1 Unit cell parameters of samples

Sample	Unit cell parameters
Sample	a/nm	c/nm
Mg_0.1	1.03705	3.71939
Mg_0.2	1.03707	3.71234
Mg_0.3	1.03542	3.71068
Mg_0.4	1.03431	3.70353
Mg_0.5	1.03412	3.70203
PDF# 70-2064	1.03500	3.70850

表2 不同Mg/(Ca+Mg)样品的化学成分

Table 2 Chemical constituents of different Mg/(Ca+Mg) samples

Mg_L	Chemical constituents/wt%			Molar ratio
Mg_L	CaO	P₂O₅	MgO	Mg_S	Mg_L/Mg_S	(Ca+Mg)/P
Mg_0.1	53.95	43.85	1.85	0.041	0.41	1.62
Mg_0.2	50.95	45.64	3.16	0.076	0.38	1.59
Mg_0.3	49.34	46.04	4.21	0.102	0.34	1.51
Mg_0.4	48.54	46.34	4.89	0.119	0.30	1.51
Mg_0.5	46.74	46.8	6.03	0.136	0.27	1.49

图2 不同Mg/(Ca+Mg)样品的SEM照片

Fig. 2 SEM images of different Mg/(Ca+Mg) samples (180℃, 6 h)(a) Mg0(HA); (b) Mg0.1; (c) Mg0.2; (d) Mg0.3; (e) Mg0.4; (f) Mg0.5

图3 不同反应时间得到的样品的XRD图谱

Fig. 3 XRD patterns of samples reacted for different time (Mg0.3, 180℃)(a) 2 h; (b) 3 h; (c) 6 h; (d) 10 h

表3 焙烧样品的晶胞参数

Table 3 Unit cell parameters of calcined samples

Calcination temperature	Chemical formula	Unit cell parameters
Calcination temperature	Chemical formula	a/nm	c/nm
As-prepared sample	Ca₁₈Mg₂H₂(PO₄)₁₄	1.03707	3.71234
950℃	Ca₁₈Mg₂(PO₄)₁₂P₂O₇	1.03472	3.71176
1200℃	Ca₁₈Mg₂(PO₄)₁₂P₂O₇	1.03412	3.71094

图4 不同反应时间得到的Mg0.3样品的SEM照片

Fig. 4 SEM images of samples reacted for different time (Mg0.3, 180℃)(a) 2 h; (b) 3 h; (c) 6 h; (d) 10 h

图5 Mg0.3样品的TG-DTA曲线

Fig. 5 TG and DTA curves of sample Mg0.3

图6 焙烧样品的XRD图谱

Fig. 6 XRD patterns of the calcined samples (a) As-prepared sample (Ca18Mg2H2(PO4)14); (b) Calcined at 950℃ (Ca18Mg2(PO4)12P2O7), 2 h; (c) Calcined at 1200℃, 2 h (Ca18Mg2(PO4)12P2O7)

参考文献 18

[1]	YASHIMA M, SAKAI A, KAMIYAMA T,et al. Crystal structure analysis of β-tricalcium phosphate Ca3 (PO4)2 by neutron powder diffraction. Journal of Solid State Chemistry, 2003, 175(2): 272-277.
[2]	ARAÚJO J C, SADER M S, MOREIRA E L,et al. Maximum substitution of magnesium for calcium sites in Mg-TCP structure determined by X-ray powder diffraction with the Rietveld refinement.Materials Chemistry and Physics, 2009, 118(2): 337-340.
[3]	MATSUNAGA K, KUBOTA T, TOYOURA K,et al. First-principles calculations of divalent substitution of Ca2+ in tricalcium phosphates. Acta Biomaterialia, 2015, 23(1): 329-337.
[4]	GRIGG A T, MEE M, MALLINSON P M,et al. Cation substitution in β-tricalcium phosphate investigated using multi-nuclear, solid-state NMR. Journal of Solid State Chemistry, 2014, 212: 227-236.
[5]	NABIYOUNI M, REN Y, BHADURI S B.Magnesium substitution in the structure of orthopedic nanoparticles: a comparison between amorphous magnesium phosphates, calcium magnesium phosphates, and hydroxyapatites.Materials Science and Engineering C, 2015, 52: 11-17.
[6]	HABRAKEN W, HABIBOVIC P, EPPLE M,et al. Calcium phosphates in biomedical applications: materials for the future? Materials Today, 2016, 19(2): 70-87.
[7]	QIN S, LU A H, WANG C Q.The minerals in the human body.Earth Science Frontiers, 2008, 15(6): 32-39.
[8]	XIE X D, CHEN M.Formation conditions of tuite.Geochimica, 2008, 37(4): 297-303.
[9]	JANG H L, JIN K, LEE J,et al. Revisiting whitlockite, the second most abundant biomineral in bone: nanocrystal synthesis in physiologically relevant conditions and biocompatibility evaluation. Acs Nano, 2014, 8(1): 634-641.
[10]	KIM H D, JANG H L, AHN HY,et al. Biomimetic whitlockite inorganic nanoparticles-mediated in situ remodeling and rapid bone regeneration. Biomaterials, 2017, 112: 31-43.
[11]	ZHANG J T, LIU W Z, SCHNITZLER V,et al. Calcium phosphate cements for bone substitution: chemistry, handling and mechanical properties. Acta Biomaterialia, 2013, 10(3): 1035-1049.
[12]	FURUZONO T, WALSH D, YASUDA S,et al. Preparation of plated β-tricalcium phosphate containing hydroxyapatite for use in bonded inorganic-organic composites. Journal of Materials Science, 2005, 40(9): 2595-2597.
[13]	SWAIN S K, GOTMAN I, UNGER R,et al. Microstructure, mechanical characteristics and cell compatibility of β-tricalcium phosphate reinforced with biodegradable Fe-Mg metal phase. Journal of the Mechanical Behavior of Biomedical Materials, 2016, 53: 434-444.
[14]	SHAVANDI A, BEKHIT E D A, ALI A,et al. Microwave-assisted synthesis of high purity β-tricalcium phosphate crystalline powder from the waste of green mussel shells. Powder Technology, 2015, 273: 33-39.
[15]	TORRES P M, GOUVEIA S, OLHERO S,et al. Injectability of calcium phosphate pastes: effects of particle size and state of aggregation of β-tricalcium phosphate powders. Acta Biomaterialia, 2015, 21: 204-216.
[16]	HASHIMOTO K, KOBAYASHI T, TODA Y.Chemical composition of synthetic whitlockite prepared by hydrothermal method.Inorganic Materials, 1999, 6(279): 110-116.
[17]	GOPAL R, CALVO C, ITO J,et al. Crystal structure of synthetic Mg-whitlockite, Cal8Mg2H2(PO4)14. Canadian Journal of Chemistry, 2011, 52(7): 1155-1164.
[18]	BOANINI E, GAZZANO M, BIGI A.Ionic substitutions in calcium phosphates synthesized at low temperature.Acta Biomaterialia, 2010, 6: 1882-1894.