| Summary: | 碩士 === 大同大學 === 化學工程學系(所) === 100 === Terephthalic acid is widely used in a variety of petrochemical products, such as polyethylene terephthalate, polyester fiber, and polyester film. For every ton of TPA produced, about 3–10 m3 of wastewater is produced with very high amount of organic content (5–300 g/L COD). So terephthalic acid process wastewater needs suitable treatment to comply with the emissions standards.
In this study, activated carbon was modified with copper nitrate by impregnation method, and then used to adsorb and separate terephthalic acid and benzoic acid to compare with the performance of the original activated carbon. Because the modification process involved many influencing factors, the Plackett-Burman design method was applied to screen the main factors, and the full factorial experiment design method was used to find the main effects and interaction effects. Finally, single and binary component of adsorption equilibriums were measured at different temperatures and suitable adsorption isotherm models were found.
According to the Plackett-Burman method, the nitric acid concentration, nitric acid impregnation time, impregnant concentration, and calcination temperature are important factors for carbon adsorption capacity. From the full factorial design method, the best conditions found were 1N nitric acid concentration, 24hr nitric acid impregnation time, 0.05N impregnant concentration, and 250℃ calcination temperature. The adsorption equilibrium results showed that the adsorption capacities for benzoic acid and terephthalic acid onto the modified carbon were higher than the original carbon; both capacities increased with increasing temperature. The binary adsorption data can be successfully predicted by the IAST along with the Freundlich model or the modified Langmuir model.
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