A magnetically recyclable magnetic graphite oxide composite functionalized with polydopamine and β-cyclodextrin for cationic dyes wastewater remediation: Investigation on adsorption performance, reusability and adsorption mechanism

Abstract

In this work, a novel polydopamine and β-CD polymer co-decorated magnetic graphene oxide composite adsorbent (PDA/MGO/CA-CD) was facilely constructed, and systematically characterized by various characterization techniques. Subsequently, it was applied as a versatile adsorbent for purification of cationic dyes Methylene blue, Malachite green, and Crystal violet in wastewater. Under optimal conditions, the maximum adsorption capacities of PDA/MGO/CA-CD towards MB, MG, and CV were 1372.32, 822.39, and 570.79 mg/g, respectively. The adsorption kinetics investigate demonstrated that the adsorption experimental data fitted well with the pseudo-second-order kinetic model. Simultaneously, the adsorption isotherms data indicated good correlation coefficient and low error function for the Langmuir isotherm model. The thermodynamic consequences showed that the adsorption of cationic dyes on PDA/MGO/CA-CD was a spontaneous and endothermic process. Interestingly, the PDA/MGO/CA-CD can selectively capture cationic dyes from mixed cationic/anionic dye solutions. As-fabricated adsorbent possesses abundant functional groups which could adsorption cationic dyes via electrostatic interaction, hydrogen bonding, Yoshida H-bonding, π-π conjugation interaction, n-π interaction, and “host-guest” interaction. It was eventually revealed that the as-prepared PDA/MGO/CA-CD adsorbent was easy to be separated after adsorption and exhibited good reusability. More importantly, application on real water samples confirmed the high performance and potential of as-fabricated adsorbent for real cationic dyes remediation of environmental.