摘要
Powdered activated carbon（PAC） adsorption of two fishy odorants, trans,trans-2,4-heptadienal（HDE） and trans,trans-2,4-decadienal（DDE）, was investigated. Both the pseudo first-order and the pseudo second-order kinetic models well described the kinetics curves, and DDE was more readily removed by PAC. In isotherm tests, both Freundlich and Modified Freundlich isotherms fitted the experimental data well. PAC exhibited a higher adsorption capacity for DDE than for HDE, which could be ascribed to the difference in their hydrophobicity. The calculated thermodynamic parameters（ΔG^0, ΔH^0, and ΔS^0） indicated an exothermic and spontaneous adsorption process. PAC dosage, p H, and natural organic matter（NOM） presence were found to influence the adsorption process. With increasing PAC dosage, the pseudo first-order and pseudo second-order rate constants both increased. The value of p H had little influence on HDE or DDE molecules but altered the surface charge of PAC, and the maximum adsorption capacity occurred at p H 9. The presence of NOM, especially the fraction with molecular weight less than1 k Dalton, hindered the adsorption. The study showed that preloaded NOM impaired the adsorption capacity of HDE or DDE more severely than simultaneously fed NOM did.
Powdered activated carbon（PAC） adsorption of two fishy odorants, trans,trans-2,4-heptadienal（HDE） and trans,trans-2,4-decadienal（DDE）, was investigated. Both the pseudo first-order and the pseudo second-order kinetic models well described the kinetics curves, and DDE was more readily removed by PAC. In isotherm tests, both Freundlich and Modified Freundlich isotherms fitted the experimental data well. PAC exhibited a higher adsorption capacity for DDE than for HDE, which could be ascribed to the difference in their hydrophobicity. The calculated thermodynamic parameters（ΔG^0, ΔH^0, and ΔS^0） indicated an exothermic and spontaneous adsorption process. PAC dosage, p H, and natural organic matter（NOM） presence were found to influence the adsorption process. With increasing PAC dosage, the pseudo first-order and pseudo second-order rate constants both increased. The value of p H had little influence on HDE or DDE molecules but altered the surface charge of PAC, and the maximum adsorption capacity occurred at p H 9. The presence of NOM, especially the fraction with molecular weight less than1 k Dalton, hindered the adsorption. The study showed that preloaded NOM impaired the adsorption capacity of HDE or DDE more severely than simultaneously fed NOM did.
基金
supported by the National Natural Science Foundation of China (No. 51290284)
