Adsorption Properties of Polydopamine Modified Sepiolite for Organic Dyes

Polydopamine-modified sepiolite composite（PDA@SEP）was prepared by dopamine self⁃

polymerization. The composite was characterized by X-ray diffractometer（XRD），Fourier transform infra⁃

red spectrometer（FT-IR），specific surface area and aperture distribution measuring instrument. The adsorp⁃

tion properties and renewability of cationic organic dyes Crystal Violet（CV），Malachite Green（MG），

Methylene Blue（MB）and Rhodamine B（RhB）were studied. The results showed that the maximum adsorp⁃

tion capacities of polydopamine modified sepiolite for CV，MG，MB and RhB were 1 501.1，555.1，120.9

and 149.3 mg/g，respectively，which were higher than those of unmodified sepiolite. The adsorption process

follows to the pseudo-second-order kinetic model and Langmuir isotherm.The adsorption and desorption test

of 0.1 mol/L hydrochloric acid as eluent showed that the removal rate of organic dyes by PDA@SEP used for

5 cycles remained above 40%，indicating that the composite had good reusability. In summary，PDA@SEP

is an environmental mineral material with great potential for removing organic dyes from wastewater.

1. School of Environment and Resources，Southwest University of Science and Technology；

2. Key Laboratory of Solid Waste Treatment and Recycling，Ministry of Education；

3.Non-metallic Mineral Powder Modification and High Quality Utilization Engineering Laboratory

Abstract: