Tác động của hệ dung môi h2o/c2h5oh đến tính chất của xúc tác quang fenton cufe2o4 cho phản ứng giảm cấp methylene blue

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Tác giả: Văn Vĩnh Lê, Thị Mai Loan Nguyễn, Thị Thanh Thủy Nguyễn, Nguyễn Hữu Thịnh Phạm, Hớn Quốc Trần

Ngôn ngữ: vie

Ký hiệu phân loại: 541.2 Theoretical chemistry

Thông tin xuất bản: Phát triển khoa học và công nghệ: khoa học tự nhiên (đhqg tp. hồ chí minh), 2022

Mô tả vật lý: 2095-2102

Bộ sưu tập: Metadata

ID: 489656

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Bài viết trình bày việc sử dụng phương pháp đơn giản là sự đồng kết tủa trong hệ dung môi nước và ethanol để điều chế xúc tác Fenton dị thể CuFe2O4 sử dụng cho phản ứng giảm cấp hợp chất màu xanh methylene (MB). Hỗn hợp các tiền chất oxalate được tổng hợp từ các muối sulfate tương ứng và oxalic acid trong hệ hỗn hợp dung môi nước/ethanol. Quá trình xử lý nhiệt những hỗn hợp tiền chất tiến hành ở các nhiệt độ 600, 700 và 800 oC trong môi trường khí quyển. Sự thay đổi tỷ lệ thể tích dung môi nước và ethanol theo khuynh hướng giảm dần thể tích nước, dẫn đến giảm mức độ phân cực của dung môi và ảnh hưởng đến quá trình kết tủa tiền chất cũng như phản ứng pha rắn. Sự giảm độ phân cực của dung môi làm gia tăng nhẹ kích thước hạt và làm giảm mức độ tinh thể hóa. Các kết quả thực nghiệm cho thấy hệ dung môi nước-ethanol có tác dụng làm giảm mức độ phân tán về kích thước hạt. Trong khi đó, nhiệt độ nung tiền chất tăng dẫn đến kích thước hạt tăng và hàm lượng ion Fe3+ trên bề mặt cao hơn so với các mẫu xử lý nhiệt ở 600 và 800 oC. Các mẫu điều chế từ hệ dung môi với thể tích ethanol-nước lần lượt là 50%, 70% và nung ở 700 oC cho thấy khả năng xúc tác tốt cho phản ứng phân hủy MB khi sử dụng tác nhân oxi hóa là oxalic acid và chiếu xạ bằng tia UVA. Hiệu quả xử lý MB sau 90 phút đạt 85%.This paper reported a simple method of co-precipitation in aqueous and ethanol solvent systems to prepare a catalyze CuFe2O4 heterogeneous Fenton used for the degradation reaction of methylene blue (MB). The mixtures of oxalate precursors were prepared from the corresponding sulfate salts and oxalic acid in the solvent system of H2O/C2H5OH. The heat treatment of the precursor mixtures was carried out at 600, 700, and 800 oC in the surrounding atmosphere. The change in the volume ratio of water and ethanol with the tendency to gradually decrease the volume of water lead to a decrease in the polarity of the solvent and affected the precursors' precipitation as well as the solid phase reaction. The decrease in the solvent polarity resulted in a slight increase of the particle size and a reduction of the crystallinity. The experimental results showed that the water-ethanol solvent system had the effect of reducing the degree of dispersion in terms of the particle size. Meanwhile, the increase of the precursor calcination temperature resulted in the increased grain size and the higher concentration of Fe3+ ions on the surface compared with samples heat-treated at 600 and 800 oC. Samples, prepared from the solvent system with the ethanol-water volume of 50% or 70%, and then were calcined at 700 oC, showed good catalytic ability for the MB decomposition reaction irradiated by UVA rays and oxalic acid being used as an oxidizing agent. The MB processing efficiency after 90 minutes was 85%.

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