Khử màu các chất màu dệt nhuộm bằng xúc tác quang TiO2 dùng polyol làm chất cho electron

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Ngôn ngữ: vie

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Thông tin xuất bản: Tạp chí Phát triển Khoa học & Công nghệ: Khoa học Tự nhiên, 2018

Mô tả vật lý: tr.83

Bộ sưu tập: Báo, Tạp chí

ID: 293768

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Decolorization of textile dyes including 2,6-dichlorophenolindophenol (DCIP), congo red (CR) and methyl orange (MO) by using TiO2-based photocatalyst in the presence of polyols such as glycerol and ethylene glycol was investigated. Polyols were used as sacrificial electron donors (SEDs). The results showed that the polyols improved the rate and yield of a light-induced decolorization of dyes in comparison with a photocatalytic reaction without polyols. A possible reaction mechanism of dye decolorization by the photocatalyst in the presence of electron donors was proposed. TiO2 photocatalyst absorbed light to generate electrons (e- ) and holes (h+ ). The electrons and holes were prevented from recombining by the presence of SEDs. The free electrons and holes then involved in decolorization processes through reduction or oxidation reactions. The effects of TiO2 catalyst amounts, irradiation time and polyol concentrations on dye decolorization were investigated. The decolorization efficiency significantly increased with the increasing irradiation time, SED concentrations and certain amounts of TiO2.Trong nghiên cứu này, hỗn hợp gồm xúc tác quang TiO2 và polyol (glyecerol hoặc ethylene glycol) đã được sử dụng để khử màu các chất dệt nhuộm 2,6-dichlorophenolindophenol (DCIP), congo đỏ (CR) và methyl cam (MO). Các polyol đóng vai trò là các chất cho electron. Kết quả cho thấy rằng với sự có mặt của polyol, tốc độ và hiệu suất khử màu của TiO2 tăng lên đáng kể so với quá trình khử màu chỉ dùng TiO2. Cơ chế khử màu bằng xúc tác quang TiO2 với sự tham gia của polyol đã được đề nghị. Xúc tác quang hấp thu năng lượng từ nguồn sáng đã tạo ra các electron (e- ) và các lỗ trống (h+ ). Với vai trò là các chất cho electron, polyol đã ngăn chặn sự kết hợp lại giữa e- và h+ . Điều này tạo điều kiện cho các e- và h+ tham gia các phản ứng khử hoặc oxy hóa tạo ra các dạng không màu của chất màu dệt nhuộm. Ảnh hưởng của lượng TiO2, thời gian chiếu xạ và nồng độ của polyol lên hiệu suất khử màu cũng được khảo sát. Quá trình khử màu tăng lên đáng kể khi tăng thời gian chiếu xạ và nồng độ polyol trong một lượng nhất định TiO2.

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