Preparation of Nano-CaO using Sonication Method.
Summary: CaO is an important inorganic material, which can be applied into many aspects, such as catalysis, toxic-waste remediation, adsorbents etc. In order to make use of CaO, nano-CaO was prepared by sonication method using Ca (CH3COO)2.2H2O as precursor, NaOH aqueous solution as precipitant in this paper. Characteristics of samples were measured by TGA, XRD, TEM etc. techniques. The results showed that the size of nano-CaO 140 nm could be obtained under the conditions (calcination temperature 530 degC., calcination time 15 h, heating rate of calcination 3 degC. /min). It is a very simple and effective method to prepare nano-CaO.
In recent years, inorganic agents are being used increasingly for control of microorganisms in various areas. The key advantages of inorganic agents are improved safety and stability compared with organic antimicrobial agents. Basic metal oxides have been shown to exhibit antibacterial activity, where particle size of the oxides appears to have an impact.
Nano CaO can be used as bactericide, adsorbents, and in particular, as a destructive adsorbent for toxic chemical agents [1, 2]. The information on the preparation of nano-CaO is limited in the literature. Two methods are typically cited in the literature for the preparation of nano- CaO: thermal decomposition [3, 4] and sol-gel method. Sol-gel method is cost-prohibitive due to high cost of reagents and laboriousness of the process. For thermal decomposition method, CaO is obtained directly through calcinating CaCO3, requiring high calcination temperatures, which makes it difficult to obtain nano-scale CaO. However, microscale CaO (above 100 nm), is easily obtained through calcinating CaCO3 . Recent studies have shown sono-chemical effects on the acceleration of chemical effects involved in the synthesis of novel nanomaterials in aqueous solutions [6, 7].
Chemical effect of ultrasound originates from the formation of ultrasonic cavitation, the growth and collapse of microbubbles in the liquid phase generating very high temperature and pressure followed by rapid cooling. These extreme conditions have been exploited for the preparation of nanoparticulate metal oxides [8, 9]. This paper presented a new sonication route for preparing CaO nanoparticles. It is the first time to prepare nano CaO using sonication method.
Results and Discussion
According to TGA of Ca(OH)2 (Fig. 1), there were two major weight losses: from 350 to 450 degC. and from 500 to 700degC. The exothermic peak at 550 degC. was assigned to remove of chemisorbed water. This result was the same as reported by Olga . The peak at 400degC. was assigned to the decomposition of Ca(OH)2 to CaO + H2O. The 20 % weight loss was well corresponded with the calculated weight loss from the reaction. CaO nano- particles could be obtained at 530 degC. in this paper. The calcinations temperature was much lower than that reported by Bellobono .
The structure of nano-CaO was characterized by XRD (Fig. 3). All peaks were consistent with the peaks of standard CaO. XRD patterns showed the crystallite size calculated using Scherrer's formula was about 139 nm. No peaks from any other phases of CaO were observed.
TEM of CaO nano-particles were illustrated in Fig. 4. From Fig. 4, CaO nano-particles could be dispersed very well in ethanol. Few aggregate could be found. CaO powder appeared with two ranges (15-20 nm and 130-150 nm). The result matched with the particle size calculated using XRD. The particles were regular and spherical in shape.
Ca (CH3COO)2.2H2O (Mallinkrodt baker inc, ACS); Sodium hydroxide (BMD chemicals inc, ACS); Other reagent were obtained from local supplies.
Preparation of CaO Nano-Particles
Ca (CH3COO)2. 2H2O was dissolved in ethanol solution under room temperature. It kept at 0degC. for 24 h. Then NaOH solution was dropped into above solution under ultrasound. After being sonicated about 15 min, the transparent solution could be obtained. The solution was removed all organic substances by reduced distillation. Then it was treated at 80 degC. for about 1 h under vacuum condition. Finally, CaO nano-particles could be obtained through calcination under the conditons calcinations temperature 530 degC, calcination time 15h, heating rate of calcination 3 degC /min).
Characteristics measurement of CaO nanoparticles were described previously in our group [5, 11, 12].TGA measurements were carried out using Netzsch STA 409 Apparatus; The size and Particle size distribution in ethanol was recorded on Submicron Particle Sizer (NICOMP 370, USA);TEM photomicrographs were obtained using Philips 201
Transmission Electron Microscope. The pictures were taken at 80 kV. The deposit was scraped away from the support and then transferred to the Fromvar 1595 E (Merck) membrane coated Cu grid (mesh 400); Rigaku Geiferflex X-ray diffractometer with Ni-filtered Cu Ka radiation (40 kA, 30 mV) was used to determine the crystallinity and phase of the samples.
CaO nano-particles were prepared by sonication method using Ca (CH3COO)2.2H2O as precursor, NaOH aqueous solution as precipitant. It was simple and effective method to prepare CaO nano-particles.
1. B. K. Olga, L. Isabelle and V. Alexander, Chemistry of Materials, 9, 2468 (1997).
2. K. Olga, X. L. Yong and J. K. Kenneth, Chemistry of Materials, 5, 500 (1993).
3. I. R. Bellobono, E. Selli and L. Righetto, Materials Chemistry and Physcis, 19, 131 (1988).
4. I. R. Bellobono, L. Castellano and A. Tozzi, Materials Chemistry and Physcis, 28, 69 (1991).
5. Z. X. Tang, D. Claveau, R. Corcuff, .Belkacemi and J. Arul, Materials Letters, 62, 2096 (2008).
6. S. Dash, M. Kamruddin, P. K. Ajikumar, A. K. Tyagi and R. Baldev, Thermochim Acta, 363, 129 (2000).
7. T. H. Hyeon, M. M. Fang and K. S. Suslick, Journal of the American Chemical Society, 118, 5492 (1996).
8. K. S. Suslick and G. Price, Annual Review of Materials Science, 29, 295 (1999).
9. E. Alvarado, L. M. T. Martinez and A. F. Fuentes, Polyhedron, 19, 2345 (2000).
10. S. Ardizzone, C. L. Bianchi and B. Vercelli, Surface and Colloid Science, 144, 9 (1998).
11. L. E. Shi, X. J. Fang, Z. L. Zhang, T. Zhou, D. Jiang, H. H. Wu and Z. X. Tang, International Journal of Food Science and Technology, 47, 1866 (2012).
12. Z. X. Tang and L. E. Shi, Ecletica Quimica, 33, 15 (2008).
1Department of Food Science, Anqing Vocational and Technical College, 246003, Anqing, Anhui, China., 2College of Life and Environmental Sciences, Hangzhou Normal University, 310016, Hangzhou, Zhejiang,China., firstname.lastname@example.org*, email@example.com
|Printer friendly Cite/link Email Feedback|
|Author:||Zhen-Xing Tang; Xiu-Juan Fang; Zhi-Liang Zhang; Ling-Xia Pan; Xin-Yi Zhang; Qing-Qing Pan; Lu-E Shi|
|Publication:||Journal of the Chemical Society of Pakistan|
|Date:||Dec 31, 2012|
|Previous Article:||Application of Nano-Baskets and Hyphenated Emulsion Liquid Membrane-Nuclear Magnetic Resonance (ELM-NMR) in Metabolomics of Rat Serum.|
|Next Article:||Flotation-Spectrophotometric Method for Separation and Determination of Trace Amounts of Copper.|