Preparation Of Cationic β-cyclodextrin/montmorillonite Composite Material And Its Application In Dye Wastewater Treatment

Dye wastewater has the characteristics of high chroma,large discharge,complex composition,and difficult to degrade.It is one of the important sources of water pollution.Researchers have prepared a series of adsorbents for the restoration of the water environment in accordance with the characteristics of this type of wastewater.I n recent years,β-cyclodextrin and montmorillonite have been widely reported as environmental protection materials in the field of adsorbents.According to the characteristics of dye wastewater,the cationβ-Cyclodextrin（β-CD）,methacryloxyethyl trimethylammonium chloride（DMC）,and montmorillonite（MMT）are used as raw materials to prepare the cationβ-Cyclodextrin/montmorillonite composite adsorbent（β-CD-DMC/MMT）.Theβ-CD-DMC/MMT was characterized and analyzed by infrared spectroscopy（FT-IR）,X-ray diffraction（XRD）,scanning electron microscopy（SEM）,and thermogravimetric（TG）testing methods.The results showed thatβ-CD was introduced The quaternary ammonium salt group and MMT help to improve the adsorption performance of the composite adsorbent.The adsorption process ofβ-CD-DMC/MMT on Congo red（CR）,methyl orange（MO）and heavy metal ions Cr⁶⁺was studied with pH,oscillation time,and initial concentration as influencing factors.The results showed that:when the initial concentration of CR s olution was50mg/L,pH was 6,and oscillated for 150 minutes,the adsorption reached equilibrium,and the adsorption rate was 99.2 1%.After 5adsorption-desorption experiments,the adsorption rate was 87.05%.The adsorption capacity of MO solution changes with the change of pH.When the pH was 4 and the shaking time was 130 min,the adsorption rate reached 96.73%.After 5 adsorption-desorption experiments,the adsorption rate was 82.56%.The adsorption results of Cr⁶⁺solution showed that when the pH was 7 and shaking for 150 minutes,the adsorption rate was 65.02%.After 5 adsorption-desorption experiments,the adsorption rate was 52.13%.The kinetic study shows that the adsorption process ofβ-CD-DMC/MMT on the anionic dye CR,MO solution and Cr⁶⁺solution follows a pseudo-second-order kinetic model.In addition,the adsorption of CR,MO and Cr⁶⁺is fitted with isotherm equations.The adsorption of CR and MO can be described by the single-layer adsorption equation Lan gmuir model.The adsorption of Cr⁶⁺is more in line with the Freundlich model.It can be seen from the experiment thatβ-CD-DMC/MMT has potential practical significance as a composite adsorbent for removing anionic dyes and heav y metal ions.