tailieunhanh - Environmental aspects of textile dyeing - Chapter 8

Sự hiện diện của màu sắc dễ nhận thấy trong chất thải thủy sản xảy ra trong một số các thiết lập công nghiệp. Nổi bật trong số này là giấy và bột giấy, chế biến thực phẩm và các ngành công nghiệp chế biến ướt dệt. Trong trường hợp cuối cùng, màu sắc trong nước thải là thuốc nhuộm đó không phải là cố định trong nhuộm sợi, vải, sợi, hàng may mặc đang được xử lý. Mức độ màu trong nước thải có thể là một vấn đề có thể phụ thuộc vào các lớp học của thuốc. | 8 Chemical treatment of textile dye effluent I. R. HARDIN University of Georgia USA Introduction The presence of highly visible colour in aquatic waste occurs in a number of industrial settings. Prominent among these are the pulp and paper food processing and textile wet processing industries. In the case of the last of these the colour in the waste water is dye that is not fixed in the dyeing of the fibre yarn fabric or garments being processed. The degree to which colour in waste water may be a problem can depend on the class of dye being used the type of stream being discharged into the degree to which the textile effluent contributes to the flow of the receiving body the geographic location of the plant and even the political environment that the plant operates in. The amount of dye used each year in the textile industries of the world has been variously estimated but it is undoubtedly more than 700000 tons per year. Depending on the particular dye class in use the percentage of dye that remains unfixed to the fibre during the dyeing process and finds its way into the effluent can range from 5-50 . This can present a very serious problem for the textile manufacturer who finds himself needing to meet effluent standards that include the colour in that water stream as well as all the other standards dealing with such measures as pH dissolved solids chemical oxygen demand COD biological oxygen demand BOD and total organic carbon TOC . Colour Colour is an intriguing part of our everyday lives. An intense red colour in the fabric of the garment that we wear may be highly satisfying but that same red colour in the stream that flows through our grassy park is completely objectionable. It is not the colour per se that offends but colour that is out of place that does not belong. Dyes the molecules that produce the colour on fabrics have very high tinctorial power absorbing intensely in the part of 191 2007 Woodhead Publishing Limited 192 Environmental aspects of