In the current era of industrialization, environmental pollution has become one of the major issues all over the world. Among various natural resources, soil and water are the most significant ones. However, these two resources are now being constantly polluted by various industrial wastes, especially by dyes, and other organics. Therefore, breakdown or removal of such organics before draining them in the environment is an urgent to save the biological ecosystem of water and soil. Inorganic photocatalysis is a major solution to break such organics into non-poisonous small compounds like water, CO2, etc. Among various inorganic photocatalysts, bismuth and its nanostructures (BiNMs) are always the best choice due to its immense less toxicity, cheapness, incredible stability, radiopacity, tunable band gap, etc. However, the involvement of toxic chemical constituents and organic solvents in the chemical synthetic procedure of BiNMs limits the application potential of Bi. Therefore, this work aims at developing a safe and aqueous synthesis method for BiNMs using safe and water-soluble thiols as alternative to toxic and flammable reducing agents such as NaBH4 or hydrazine. Finally, the synthesized BiNMs will be applied to environmental purification such as waste water-treatment for the removal of organic dyes.

The project has developed a safe and facile synthesis method for BiNMs in aqueous media using safe water-soluble thiols such as sodium 3-mercaptopropane sulfonate, sodium 4-mercaptobutane sulfonate, etc. as a safe replacement of toxic, flammable, and hazardous reducing agents that extensively used in the synthesis of BiNMs. The thiols act as reducing agent and the reactions between Bi(OAc)3 and thiol provided small and single-nano-sized BiNMs, specially bismuth nanoparticles (BiNPs) in the size range 10-15 nms. Various parameters such as temperature, concentration, pH, pKa, etc. were investigated to control the size, morphology, and yield of BiNMs. Reaction under reflux condition and aminoethanol derivatives as base having better aqueous solubility improved the quality and yield of BiNPs. The synthesized BiNMs were also converted into BiOCl nanoparticles just by simple treatment with aqueous solution of HCl followed by sonication. The synthesized BiNPs and converted BiOCl NPs were applied as catalysts for the photo-degradation of Rhodamine B dye, as a representative of xanthene dyes and found excellent photocatalytic performance. However, BiOCl NPs showed superior catalytic activity over BiNMs regarding the faster kinetics and degradation ability at neutral media while BiNPs were only active at acidic pH.

https://sdgs.yamagata-u.ac.jp/project/detail_423.html

ISLAM MD SYEDUL

工学部

tcf76780@st.yamagata-u.ac.jp

ISLAM MD SYEDUL, Bungo Ochiai (Supervisor)

山形大学基金（学部等への支援）
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