| In recent years,various pollutants from environmental pollution such as organic dyes,pesticides,and plasticizers existing in water have caused a great threat to human safety.In which,because it's difficult to degrade and highly toxic,aromatic organic pollutants containing a benzene ring structure are likely to cause serious persistent pollution to the environment,which.Therefore,it is very essential to find a solution to efficiently remove aromatic organic pollutants from the polluted water.Adsorption technology is an efficient,cost-effective,and simple method to clean out organic pollutants existing in the water.The performance of the adsorbent plays a significant role in the adsorption process.In order to more efficiently remove water pollutants,the adsorbent is required to have a high specific surface area,a high porosity,and a characteristic structure that can interact more strongly with pollutant molecules.To this end,this work used green and easily available?-cyclodextrin??-CD?as a raw material to prepare?-CD-based porous materials by different methods,and batch adsorption experiments were carried out.Moreover,the adsorption mechanism was discussed.The specific research contents and conclusion are demonstrated as follows:Firstly,for improving the adsorption performance of the non-porous?-CD polymer?TTI-CDP?,hyper-crosslinked?-cyclodextrin polymers?TTICDP-x?were synthesized by an external weaving method using a variety of cross-linking agents.The TTICDP-BCMP weaved from the cross-linking agent4,4'-bis?chloromethyl?biphenyl?BCMP?had a multi-stage pore structure,a specific surface area of 1638.48 m2·g-1,a pore volume of 2.02 cm3·g-1,and high thermal stability.It can efficiently remove many types of pollutants.The multi-stage pore structure of TTICDP-BCMP can improve the adsorption rate of pollutants.The adsorption equilibrium of the TTICDP-BCMP for rhodamine B?RB?,bisphenol A?BPA?,and 2,4,6-trichlorophenol?2,4,6-TCP?can achieve in a short time of 50,3,and 5 min,respectively.The adsorption process of RB on TTICDP-BCMP belongs to chemical-physical mixed adsorption,and the adsorption process of BPA and 2,4,6-TCP on it belongs to physical adsorption,with high KF and n values.After 6 regenerations,the adsorption performance of TTICDP-BCMP did not decrease significantly.The porous adsorbent had various weak interaction forces such as electrostatic force,hydrogen bond,?-?interaction,and host-guest interaction between pollutant molecules,resulting in its efficient adsorption capacity for many types of pollutants.Secondly,TTI-CDP containing C,H,O,N elements is an easily available and cost-effective carbon source.TTISi-CDP was prepared using the hard template method,and?-CD-based porous carbon materials?C-CDP-x?were synthesized by step carbonization and different amounts of activator?KOH?.Through characterization,it was found that C-CDP-x is a highly disordered carbon material.Among them,C-CDP-4 prepared with a higher dosage of activator had a specific surface area of 3982 m2·g-1,a pore volume of 1.96cm3·g-1,and possesses a variety of functional groups containing N and O.Through the single-component static adsorption experiment,the following conclusions were found.The adsorption of C-CDP-4 to o-chlorophenol?OCP?,2,6-dichlorophenol?2,6-DCP?and 2,4,6-trichlorophenol?2,4,6-TCP?can be reach balance in a short time;The adsorption process of three kinds of chlorophenols on C-CDP-4 was the physical adsorption process of entropy increasing and heat release;C-CDP-4 had good reuse performance for three kinds of chlorophenols.The results show that the microporous structure of C-CDP-4 is conducive to the adsorption of small molecular aromatic pollutants such as chlorophenol.In the multi-component adsorption experiment,when the concentrations of OCP and 2,6-DCP are relatively high,competitive adsorption exists,and C-CDP-4 has the highest adsorption selectivity for 2,4,6-TCP.The weak interactions in the adsorption process were analyzed through theoretical calculations.The adsorbent mainly adsorbed chlorophenol pollutants through?-?interaction and van der Waals force.Finally,to prepare a mesoporous adsorbent capable of removing macromolecular dyes,using SBA-15 as a carrier,?-CD was grafted onto the surface of SBA-15 through a condensation reaction to synthesize SBA15-A-CDx with different?-CD loading.Among them,SBA15-A-CD2 had a specific surface area of 256.03 m2·g-1,has ordered pores,and is an adsorbent that can efficiently remove methyl blue?MB?.In the adsorption experiment,SBA15-A-CD2 can adsorb 95%MB in the aqueous solution within 25 min,and the maximum adsorption capacity of MB at 25 oC is 1790.92 mg·g-1.After repeated regeneration 6 times,SBA15-A-CD2 also had an adsorption capacity of 383.4 mg·g-1 for MB.The adsorption mechanism was verified using two-dimensional 1H-1H ROESY spectra and theoretical calculations.The results show that there are weak intermolecular interaction forces such as host-guest interaction,hydrogen bonding,electrostatic force,hydrophobic force,and van der Waals interaction during the adsorption process.Besides,SBA15-A-CD2 has a strong adsorption capacity for a variety of macromolecular dyes?Methyl orange,Sunset yellow,Congo red?.In summary,the?-cyclodextrin-based porous adsorbents prepared in this work have an excellent ability to remove a variety of aromatic pollutants.This research has provided several promising adsorbents for removing organic pollutants from water.The adsorption mechanism was discussed in this work by studying the adsorption process and theoretical calculation.Besides,this research provides a reference for designing more efficient adsorbents in the future. |
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