Abstract
•Cu(II) adsorption increased with the increase of ionic strength at pH<8.•LiCl, NaCl, and KCl had similar effects on the Cu(II) removal.•The presence of NaCl, NaClO4, and NaNO3 improved the Cu(II) uptake.•Citric acid had significant promoting effect on the Cu(II) adsorption.•The Cu(II) adsorption process followed the pseudo-second-order rate equation.
Elucidating the influence mechanism of surrounding environmental conditions on the adsorption process is essential in application of adsorption method for heavy metal removal from wastewater. In the present work, the magnetic graphene oxide-supported β-cyclodextrin (MGO/β-CD) was synthesized and characterized by FESEM, TEM, TG–DSC, FT-IR, and zeta potential. The effects of pH, ionic strength, background electrolytes, and citric acid on the adsorption behavior of Cu(II) by MGO/β-CD were investigated. The results showed that Cu(II) adsorption was strongly dependent on solution pH and could be affected by ionic strength, background electrolytes and citric acid. The Cu(II) adsorption was increased as the NaNO3 concentration increased from 0 to 0.1M at pH<8. The presence of LiNO3, NaNO3, KNO3, NaCl, and NaClO4 enhanced the Cu(II) removal slightly. The Cu(II) adsorption was also improved by citric acid. Adsorption kinetics of Cu(II) was found to follow pseudo-second-order rate equation, and the adsorption rate was controlled by film diffusion. The adsorption data showed good correlation with the Freundlich and Temkin isotherm models. The results of this work are of great significance for the application of MGO/β-CD as a promising adsorbent material for Cu(II) removal from aqueous solution.