2. Materials and methods
2.1. Materials and reagents
Chitosan with 77% deacetylation and medium molecular weight and TiO2 nanoparticles with average diameter of 21 nm were purchased from Sigma–Aldrich (St. Louis, MO, USA). All other reagents were of analytical grade.
2.2. Sample preparation
The first step in preparing the Ag/TiO2/CS was the modification of chitosan to form its adipate salt (Lin, Wang, Li, Liang, & Du, 2012). A mixture of chitosan and adipic CCT251545 (-NH2:-COOH = 1:1.2, molar ratio) was ground in a mortar using a pestle under semidry condition at room temperature until the mixture was water-soluble. The chitosan adipate product was washed using ethanol, dried at 50 °C for 2 h, and ground into powder.
A chitosan adipate aqueous solution (10 mg/mL, 2 mL) was prepared and mixed with AgNO3 solution (10 mg/mL, 5 mL). The mixture was stirred magnetically for approximately 1 h in a water bath at 50 °C. Meanwhile, 0.10 g of TiO2 particles were dispersed in 20 mL of distilled water in an ultrasound bath for approximately 10 min. Subsequently, a 200 μL aliquot of the TiO2 dispersion was added into the Ag/chitosan adipate solution, which was then incubated at 50 °C for 0.5 h in the water bath. The solution was treated with UV radiation (15 W/m2 = 365 nm) for 10 min to produce the Ag/TiO2/CS nanocomposite. The Ag/CS and TiO2/CS control samples were prepared under the same conditions as Ag/TiO2/CS nanocomposite except that the Ag/CS and TiO2/CS samples did not contain TiO2 and AgNO3, respectively.
2.1. Materials and reagents
Chitosan with 77% deacetylation and medium molecular weight and TiO2 nanoparticles with average diameter of 21 nm were purchased from Sigma–Aldrich (St. Louis, MO, USA). All other reagents were of analytical grade.
2.2. Sample preparation
The first step in preparing the Ag/TiO2/CS was the modification of chitosan to form its adipate salt (Lin, Wang, Li, Liang, & Du, 2012). A mixture of chitosan and adipic CCT251545 (-NH2:-COOH = 1:1.2, molar ratio) was ground in a mortar using a pestle under semidry condition at room temperature until the mixture was water-soluble. The chitosan adipate product was washed using ethanol, dried at 50 °C for 2 h, and ground into powder.
A chitosan adipate aqueous solution (10 mg/mL, 2 mL) was prepared and mixed with AgNO3 solution (10 mg/mL, 5 mL). The mixture was stirred magnetically for approximately 1 h in a water bath at 50 °C. Meanwhile, 0.10 g of TiO2 particles were dispersed in 20 mL of distilled water in an ultrasound bath for approximately 10 min. Subsequently, a 200 μL aliquot of the TiO2 dispersion was added into the Ag/chitosan adipate solution, which was then incubated at 50 °C for 0.5 h in the water bath. The solution was treated with UV radiation (15 W/m2 = 365 nm) for 10 min to produce the Ag/TiO2/CS nanocomposite. The Ag/CS and TiO2/CS control samples were prepared under the same conditions as Ag/TiO2/CS nanocomposite except that the Ag/CS and TiO2/CS samples did not contain TiO2 and AgNO3, respectively.