Preparation and performance of different aluminum filmson titanium dioxide surface
-
摘要: 以偏铝酸钠、硫酸铝、磷酸为原料在不同pH条件下制备不同铝膜钛白,采用XRD、红外光谱、热重分析、SEM、BET、ZETA电位等分析了不同铝膜的晶体结构、热稳定性、微观形貌和物理性能。结果表明:不同pH获得的水合氧化铝ZETA电位均为正值,亲水性能不佳,而磷酸铝ZETA电位为负值,具有很好的亲水性能。pH=4~5时获得的水合氧化铝为近球形的无定型结构,在200 ℃和930 ℃时失去其结合水; pH=8~9时得到的絮状勃姆石结构AlO(OH),拥有极大的比表面积,在402 ℃失去结合水;pH=10~10.5时得到界面清晰、大小不均匀的颗粒状三羟铝石块,分别在297.5 ℃和513 ℃失去结合水。在偏铝酸钠中加入磷酸制备得到的是无定型的磷酸铝,其形貌为球形小颗粒团聚成的聚集体。所制备的铝膜在紫外区吸光度由强到弱的顺序是无定型水合氧化铝>磷酸铝>三水铝石>勃姆石型水合氧化铝。几种铝化合物包覆在二氧化钛表面均能提高其颜料性能,但水合氧化铝会降低二氧化钛的水分散性。Abstract: Using sodium metaaluminate, aluminum sulfate and phosphoric acid as raw materials, different aluminum films were prepared at various pH values. Crystal structure, thermal stability, microstructure and physical properties of the films were analyzed by XRD, infrared spectroscopy, thermogravimetry, SEM, BET, ZETA potential. The results show that the ZETA potentials of the hydrated alumina obtained at different pH are all positive with poor hydrophilic properties, while the ZETA potential of aluminum phosphate is negative with good hydrophilic properties. The hydrated alumina obtained at pH = 4~5 has a nearly spherical amorphous structure, and it loses the bound water at 200 ℃ and 930 ℃. AlO(OH) obtained at pH = 8~9 has a flocculent boehmite structure with a large specific surface area and it loses the bound water at 402 ℃. The granular bayerite block with clear interface and uneven size distribution can be obtained at pH = 10~10.5, which loses the bound water at 297.5 ℃ and 513 ℃, respectively. Amorphous aluminum phosphate is prepared by adding phosphoric acid into sodium metaaluminate, whose morphology is an aggregate of spherical small particles. The order of absorption in the ultraviolet region from strong to weak is amorphous hydrated alumina> aluminum phosphate> gibbsite> boehmite hydrated alumina. The pigment performance of titanium dioxide can be improved by coating of these aluminum compounds on the surface of titanium dioxide, but hydrated alumina will reduce the water dispersibility of titanium dioxide.
-
Key words:
- TiO2 /
- hydrated alumina /
- aluminum phosphate /
- thermal stability /
- water dispersibility
-
表 1 不同铝化合物的比表面积和孔径
Table 1. Specific surface area and pore size of different aluminum compounds
样品名称 比表面积/(m2·g−1) 平均孔径/nm 孔体积/(cm3·g−1) A 47.49 2.168 0.015 B 264.12 2.196 0.097 C 19.48 2.212 0.010 D 40.86 2.163 0.014 表 2 不同结构铝化合物的物理性能
Table 2. Physical properties of aluminum compounds with different structures
样品名称 ZETA电位/mV 干粉L 干粉a 干粉b 吸油量(100 g计)/g 2 h沉降上清液高度/cm A 18.6 95.08 −0.15 −0.31 51.72 10.0 B 18.3 94.98 −0.15 −0.33 109.66 14.5 C 25.1 94.67 −0.06 0.28 15.11 15 D −36.3 95.43 −0.18 0.06 63.06 0 注:沉降高度为2%水性浆料超声10 min后放置于100 mL玻璃管中静置1 h结果。 表 3 不同铝膜包膜工艺得到二氧化钛样品的性能
Table 3. Properties of TiO2 samples obtained by different aluminum film coating processes
包膜层 Jasn TCS L a b 吸油量(100 g计)/g Zeta电位/mV 24 h沉降高度/cm 未包膜 95.24 1982 95.42 −0.74 1.87 12.08 −49.7 0 pH=4~5 95.61 2019 95.79 −0.78 1.27 16.05 14.28 14 pH=8~9 95.72 2027 95.79 −0.73 1.29 18.24 15.93 15 pH=10~10.5 95.74 2025 95.74 −0.74 1.28 16.63 15.53 12.5 磷酸铝 95.81 2037 95.86 −0.73 1.35 15.71 −41.6 0 -
[1] (储成义. 二氧化钛表面修饰及其颜料性能研究[D]. 宁波: 中国科学院大学(中国科学院宁波材料技术与工程研究所), 2017.)Chu Chengyi. Preparation and modification of TiO2 particles and their pigment properties[D]. Ningbo: University of Chinese Academy of Sciences (Ningbo Institute of Materials Technology & Engineering Chinese Academy of Sciences), 2017. [2] Wu Jianchun, Li Li, Chen Xinhong, et al. Influence of alumina formation way on titanium dioxide[J]. Iron Steel Vanadium Titanium, 2014,35(4):20−23, 31. (吴健春, 李礼, 陈新红, 等. 氧化铝包覆方式对钛白性能的影响[J]. 钢铁钒钛, 2014,35(4):20−23, 31. doi: 10.7513/j.issn.1004-7638.2014.04.004 [3] Zhang Ruhui, Zhou Dali, Jiang Fengzhou, et al. Structure characteristics of hydrated alumina coated on titanium dioxide and its effect on water dispersibility of titanium dioxide[J]. Iron Steel Vanadium Titanium, 2016,37(3):35−40, 47. (张茹慧, 周大利, 蒋凤舟, 等. 钛白粉铝包膜的结构特性及对水分散性的影响[J]. 钢铁钒钛, 2016,37(3):35−40, 47. [4] Du Jianqiao, Zhong Benhe. Analysis of the aluminum ion deposition in the inorganic coating process for titanium dioxide[J]. Iron Steel Vanadium Titanium, 2017,38(2):70−74. (杜剑桥, 钟本和. 无机包膜过程中铝离子的行为规律分析[J]. 钢铁钒钛, 2017,38(2):70−74. doi: 10.7513/j.issn.1004-7638.2017.02.012 [5] Chu Chengyi, Yan Yugang, Sun Aihua. Study on light resistance of TiO2 / aluminum phosphate composite pigment[J]. Ningbo Chemical Industry, 2012,(4):23−30. (储成义, 晏育刚, 孙爱华. TiO2/磷酸铝复合颜料耐光性能的研究[J]. 宁波化工, 2012,(4):23−30.