Sulfur Nanoparticles Synthesis and Characterization from H2S Gas, Using Novel Biodegradable Iron Chelates in W/O Microemulsion

Abstract

Sulfur nanoparticles were synthesized from hazardous H2S gas using novel biodegradable iron chelates in w/o microemulsion system. Fe3+–malic acid chelate (0.05 M aqueous solution) was studied in w/o microemulsion containing cyclohexane, Triton X-100 andn-hexanol as oil phase, surfactant, co-surfactant, respectively, for catalytic oxidation of H2S gas at ambient conditions of temperature, pressure, and neutral pH. The structural features of sulfur nanoparticles have been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), diffused reflectance infra-red Fourier transform technique, and BET surface area measurements. XRD analysis indicates the presence of α-sulfur. TEM analysis shows that the morphology of sulfur nanoparticles synthesized in w/o microemulsion system is nearly uniform in size (average particle size 10 nm) and narrow particle size distribution (in range of 5–15 nm) as compared to that in aqueous surfactant systems. The EDS analysis indicated high purity of sulfur (>99%). Moreover, sulfur nanoparticles synthesized in w/o microemulsion system exhibit higher antimicrobial activity (against bacteria, yeast, and fungi) than that of colloidal sulfur.

Growth kinetics of sulfur nanoparticles in aqueous surfactant solutions

“…[18,19]. Some recent studies [1,[3][4][5][6][7] have reported the novel applications of sulfur nanoparticles, and subsequently researchers are also exploring the novel synthesis routes [8,[11][12][13][14][15]. In our previous study, we also have reported an easy route for generation of sulfur nanoparticles in aqueous surfactant media [11].…”

“…Colloidal or nano sized sulfur particles were synthesized by different routes such as acid hydrolysis of sodium thiosulphate [8][9][10][11], polysulfide decomposition [12,13], H 2 S reduction by Fe-chelate [14], ultrasonic treatment of sulfur-cystine solution [15]. In our previous study, the advantages and disadvantages of different synthesis methods were discussed to justify the need of an aqueous based easy synthesis route of sulfur nanoparticles synthesis [11].…”

Synthesis of sulfur nanoparticles in aqueous surfactant solutions

“…Despite many exciting applications, there are only a few recent literatures available on synthesis of sulfur nanoparticles by different investigators [9][10][11][12] in both aqueous and microemulsion phase by different routes. Deshpande et al [9] have synthesized sulfur nanoparticles from H 2 S gas by using biodegradable iron chelate catalyst in reverse microemulsion technique.…”

“…Deshpande et al [9] have synthesized sulfur nanoparticles from H 2 S gas by using biodegradable iron chelate catalyst in reverse microemulsion technique. They found a-sulfur or rhombic sulfur of average particle size 10 nm with a particle size range of 5-15 nm.…”

“…Now, realizing the importance of sulfur nanoparticles in different applications, the development of an easy synthesis method is highly essential for nanosize sulfur particles. In the method of Deshpande et al [9] H 2 S gas was used as a reactant, therefore the arrangement of the heterogeneous phase reaction (gas-liquid) between gaseous H 2 S and iron chelate solution is more complicated apart from the complexity of microemulsion. The disadvantage of the method proposed by Guo et al [10,11] polysulfide as a source of sulfur, where, micro sized sulfur particles were used as a raw material for the synthesis of polysulfide.…”