| Summary: | 碩士 === 明志科技大學 === 化學工程研究所 === 101 === The adsorption for P-Nitroaniline(PNA) by modified multiwalled carbon nanotubes (MWCNTs) were investigated in this study. MWCNTs were modified by H2SO4/HNO3,CO2 and KOH. The influences of the functional groups of MWCNTs were observed by modified MWCNTs. After modification, the MWCNTs broke into smaller sizes with defects on their surface. From Raman spectral analysis , the degree of graphitization is the order of ACID-MWCNT > COM-MWCNT > KOH-MWCNT > CO2-MWCNT. From thermogravimetry analysis, the residual mass of samples is the order of KOH-MWCNT > COM-MWCNT >ACID-MWCNT >CO2-MWCNT. From BET analysis, the surface area of samples is the order of KOH-MWCNT > CO2-MWCNT > COM-MWCNT > ACID-MWCNT. The adsorption capacity of KOH-MWCNT, CO2-MWCNT, ACID-MWCNT and COM-MWCNT were 171.3, 123.4, 26.8 and 49.6 mg/g for PNA, respectively. The adsorption processes follow a pseudo second-order kinetic rate equation. The adsorption rate is not only controlled by intra-particle diffusion but also by extra-particle diffusion. However, for MWCNT, intra-particle diffusion is not the rate-controlling step. The equilibrium adsorbing capacity of PNA increases with the increase of initial concentration. The adsorption for PNA by KOH-MWCNT or CO2-MWCNT , the adsorption process follows Freundlish adsorption isotherm. The adsorption for PNA by ACID-MWCNT or COM-MWCNT, the adsorption process follows Freundlish adsorption isotherm. At different pH values, ACID-MWCNT is not conducive to adsorption at pH 11. Increase the amount of adsorbent of different carbon nanotubes，the equilibrium adsorbing capacity changes are different. Stirring speed increased will help to improve the adsorption efficiency. In the desorption recycling, recycling rate is the order of ACID-MWCNT > COM-MWCNT > CO2-MWCNT > KOH-MWCNT.
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