| Gasoline and other light oils are likely to be volatiled and cause serious loss during the production, storage, transportation, sales and use. It can bring about a series of negative influences to human health, environment, safety, fuel quality, etc. Thus, the recovery of gasoline vapor is necessary. The adsorption technology is the matured technologies in gasoline vapor recovery, and activated carbon is its main adsorbent, with bad mechanical strength, bad regeneration, short using life and other shortcomings. Compared to activated carbon, adsorption resin has high mechanical strength, regulated pore structure, good regeneration, etc, and it has more engineering applications in the treatment of organic waste and some industrial VOCs. However, the recovery of gasoline vapor by adsorption resin has not been reported. In this paper, the adsorption equilibria of n-hexane and gasoline vapor onto different adsorbents (here we choose NDA-1800, NDA-150 and GAC) were investigated and dynamic adsorption/desorption experiments were also researched.The main contents and results are as follows:(1)The adsorption equilibria of n-hexane vapor and gasoline vapor onto the three adsorbents were investigated by the column adsorption method at the temperature of 293K,308K and 323 K. The experimental results show that:①The adsorption of n-hexane vapor and gasoline vapor onto the three adsorbents was exothermic reaction. Under the conditions of lower-temperature and higher-concentration, NDA-1800 has a similar or even more excellent adsorption characteristic to NDA-150. While under the conditions of lower-temperature and lower-concentration, NDA-150 has a similar or even more excellent adsorption characteristic to GAC.②Compared to Langmuir equation, the experimental data were found to fit well by Freundlich equation with the correlation coefficient R2>0.99.③Dubinin-Astakov equation can be used to fit the experimental data of NDA-1800, NDA-150 and GAC towards n-hexane vapor, which would be of great benefit to predict the adsorption isotherm of another temperature according to the adsorption isotherm of a given temperature.(2)The dynamic adsorptions of n-hexane vapor onto the three adsorbents were investigated by the fixed bed experiment. The first adsorption capacity per unit volume was NDA-150>GAC>NDA-1800, however, for the higher concentration of n-hexane vapor, due to the high desorption rate of NDA-1800(91%), it had the similar adsorption capacity with GAC and NDA-150, and the adsorption capacity of NDA-1800, GAC, NDA-150 were 43.7,49.4,61.5 mg/mL(3)The experimental results of gasoline vapor onto the three adsorbents show that: The desorption efficiency was NDA-1800(91%)> NDA-150(59%)≈GAC (58%). The adsorption capacity of high gasoline vapor concentration onto NDA-150,GAC and NDA-1800 were 56.9mg/mL,45.1mg/mL and 34.3mg/mL, while the difference was small, so that NDA-1800 can be used to recover high concentration of gasoline vapor.However, the adsorption capacity of low gasoline vapor concentration onto GAC,NDA-150, and NDA-1800 were 56.9 mg/mL,51.5 mg/mL and 32.2mg/mL, while the adsorption capacity of NDA-1800 was lower than GAC and NDA-150. Furthermore, the humidity effect experiment suggested that the humidity has no effect on the adsorption process.(4)The fixed bed composed of mesoporous adsorbent (NDA-1800) and microporous adsorbents (NDA-150) can be used to the efficient recovery of high concentrations of gasoline vapor. Appropriate proportion of macroporous resin (NDA-1800) could improve the adsorption capacity. When the volume ratio of NDA-1800 was less than 80%, the adsorption capacity of the NDA-1800 and NDA-150 fixed bed was better than the single GAC.
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