Method of preparing a bismuth sulfide particle containing antibacterial composition
Methods of synthesizing Bi 2 S 3 -CdS particles in the form of spheres as well as properties of these Bi 2 S 3 -CdS particles are described. Methods of photocatalytic degradation of organic pollutants employing these Bi 2 S 3 -CdS particles and methods of preventing or reducing microbial growth on a surface by applying these Bi 2 S 3 -CdS particles in the form of a solution or an antimicrobial product onto the surface are also specified.
1 . A method of preparing a Bi 2 S 3 -CdS particle-containing antibacterial composition, comprising:
mixing a bismuth(III) salt, a cadmium(II) salt, and an optionally substituted thiourea with a solvent in the presence of polyvinylpyrrolidone to form a reaction mixture;
heating the reaction mixture in an autoclave at a temperature of 100-300° C. for 2-48 hours thereby forming Bi 2 S 3 -CdS particles,
wherein the Bi 2 S 3 -CdS particles are in the form of spheres with an average diameter of 0.3-5 μm, and
wherein the Bi 2 S 3 -CdS particles exhibit a light absorbance of 0.4 to 0.8 at a wavelength of 450 to 800 nm in UV-Vis diffuse reflectance spectroscopy; and
mixing the Bi 2 S 3 -CdS particles with a carrier, solvent or adjuvant to form the Bi 2 S 3 -CdS particle-containing antibacterial composition,
wherein the Bi 2 S 3 -CdS particles comprise bismuth(III) sulfide and cadmium(II) sulfide, and
wherein the Bi 2 S 3 -CdS particle-containing antibacterial composition exhibits a minimal bactericidal concentration (MBC) of 1.25 to 5 mg/mL.
2 . The method of claim 1 , wherein an atomic ratio of bismuth to cadmium in the Bi 2 S 3 -CdS particles of the Bi 2 S 3 -CdS particle-containing antibacterial composition is in a range of 0.5:1 to 4:1, and an atomic ratio of sulfur to bismuth in the Bi 2 S 3 -CdS particles is in a range of 3:2 to 8:1.
3 . The method of claim 1 , wherein the Bi 2 S 3 -CdS particles have a BET surface area of 5-25 m 2 /g, a pore size of 10-50 nm, and a pore volume of 0.02-0.2 cm 3 /g.
4 . The method of claim 1 , wherein an amount of the Bi 2 S 3 -CdS particles in the Bi 2 S 3 -CdS particle-containing antibacterial composition is in a range of 0.1-10 g/L relative to a total volume of the mixture.
5 . The method of claim 1 , wherein the Bi 2 S 3 -CdS particles are applied onto the surface as the Bi 2 S 3 -CdS particle-containing antibacterial composition in the form of a solution comprising a solvent and 1 μg/mL to 50 mg/mL of the Bi 2 S 3 -CdS particles relative to a total volume of the solution.
6 . The method of claim 5 , wherein the solvent comprises dimethyl sulfoxide and water.
7 . The method of claim 1 , wherein an atomic ratio of bismuth to cadmium in the reaction mixture is in a range of 0.5:1 to 4:1.
8 . The method of claim 1 , wherein a molar ratio of the optionally substituted thiourea to the bismuth(III) salt is in a range of 2:1 to 10:1.
9 . The method of claim 1 , wherein the optionally substituted thiourea is thiourea of formula SC(NH 2 ) 2 .
10 . The method of claim 1 , wherein the Bi 2 S 3 -CdS particles-containing antibacterial composition consists of bismuth(III) sulfide, cadmium(II) sulfide and one or more selected from the group consisting of dimethyl sulfoxide, water and mixture thereof.
11 . The method of claim 1 , wherein the Bi 2 S 3 -CdS particles exhibit a light absorbance of 0.8 at a wavelength between 450 to 500 nm in UV-Vis diffuse reflectance spectroscopy.
12 . The method of claim 1 , wherein the Bi 2 S 3 -CdS particles exhibit a light absorbance of 0.4 at a wavelength between 750 to 800 nm in UV-Vis diffuse reflectance spectroscopy.