کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
681456 | 1460030 | 2012 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Removal of Cr(VI) from low-temperature micro-polluted surface water by tannic acid immobilized powdered activated carbon Removal of Cr(VI) from low-temperature micro-polluted surface water by tannic acid immobilized powdered activated carbon](/preview/png/681456.png)
In this study, food-grade tannic acid-immobilized powdered activated carbon (TA-PAC) was prepared, and adsorption of Cr(VI) (0.500 mg/L) onto TA-PAC as a function of pH, contact time, adsorption capacities and adsorption isotherms at 280 K was investigated. The results indicated that the immobilization process introduced abundant acid functional groups. The adsorption capacity of TA-PAC was found to be pH-dependent, and the optimal pH value was found to be 4.0. The equilibrium time was 240 min for TA-PAC. Adsorption data for total chromium were modeled using both two-parameter and three-parameter isotherm models. Freundlich and linear forms of three-parameter models yielded the best results for all of the data. Desorption studies of immobilized material suggested that the immobilization of food-grade tannic acid is steady. The adsorption mechanism of Cr(VI) on TA-PAC was assumed to be a comprehensive process consisting of surface reduction of Cr(VI), esterification between catechol and chromate, and ion exchange.
► Food-grade tannic acid immobilized PAC (TA-PAC) was prepared and characterized.
► Immobilization of tannic acid was beneficial for removal of Cr(VI) from water.
► Freundlich and three-parameter models fitted data well.
► Food-grade tannic acid is permanently immobilized.
► Adsorption mechanism of Cr(VI) on TA-PAC was a comprehensive process.
Journal: Bioresource Technology - Volume 113, June 2012, Pages 106–113