Synthesis Of Cyclodextrin Polymer And Selective Adsorption Properties Toward Phenol And Its Derivatives

Removal of phenol and its derivatives from industrial waste water has been a challenge for a long time. Cyclodextrin polymers (CDPs) can be good adsorbents toward phenol and it's derivatives due to the inclusion interaction between CD and phenol. In this paper, CDPs were synthesized successfully by inverse-phase suspension polymerization of cyclodextrin and epichlorohydrin. The influence of adsorption conditions including initial phenol concentration, contact time, temperature and particle size of CDPs on adsorption capability were investigated. Theβ-CDPs were easily recovered by ethanol as washing solvent and they could be used as recyclable adsorbents. The adsorption kinetics can be simulated by Ho-McKay model and the adsorption isotherm can be correlated to both Langmuir and Freundlich models. The results are as follows:With the increase of concentration of phenol, the adsorption capacity ofβ-CDPs increases, but the remove ratio stays about 45%; With the increase of temperature, the adsorption capacity ofβ-CDPs toward phenol decreases. This demonstrate that the adsorption process ofβ-CDPs toward phenol is exothermic; With the increase of diameter ofβ-CDPs, the adsorption capacity ofβ-CDPs toward phenol decreases. The adsorption capacity ofβ-CDPs toward phenol is 73 umol/g at 10℃, with the initial concentration of phenol of 150 mg/L, and diameter ofβ-CDPs of 1 mm.The adsorption kinetics can be simulated by HO-McKay model, and the adsorption isotherm can be correlated to both Langmuir and Freundlich models. It can be proved that the adsorption process is exothermic byΔHi<0.Under the same conditions,α-,β-,γ-CDPs have different adsorption capacity toward phenol.β-CDPs have different adsorption capacity toward phenol and m-dihydroxybenzene. Both of them demonstrate that the process is a kind of selective adsorption.The adsorption capacity ofβ-CDPs are not as better as activated carbon, however, the desorption capacity ofβ-CDPs is higher than activated carbon.β-CDPs can keep its adsorption capacity after being used for many time.