Efficient removal of Alizarin Red S from aqueous solution by polyethyleneimine functionalized magnetic carbon nanotubes.

Abstract

Alizarin Red S (ARS) has been extensively used in the dyeing industry. In order to effectively remove the ARS form dyeing wastewater, polyethyleneimine (PEI)-functionalized magnetic carbon nanotubes (PEI@MCNTs) adsorbent was successfully prepared and its adsorption performances were also investigated in detail. The PEI@MCNTs could efficiently remove the ARS from acidic aqueous solution (pH\u202f≤\u202f6.0) within 40\u202fmin under room temperature. Benefiting from a large number of adsorption sites and multiple interactions, PEI@MCNTs possessed high selectivity towards ARS with spontaneous adsorption process. The maximum adsorption capacity of PEI@MCNTs for ARS was 196.08\u202fmg\u202fg-1 obtained from Langmuir isotherm, higher than that of available conventional adsorbents. Moreover, the PEI@MCNTs could be easily collected by an external magnet, and then effectively regenerated through 10\u202fmM NaOH solution. The prepared PEI@MCNTs could be considered as the promising adsorbent for the removal of anthraquinone dyes in large-scale wastewater treatment.