The use of various magnetic adsorbents for cadmium uptake from dyes-containing wastewater

Abstract

Simultaneous presence of organic dyes with Cd(II) is possible and may affect Cd(II) removal from wastewater. This study involved various magnetic adsorbents for Cd(II) removal in the presence of various organic dyes (Tartrazine, Allura red, Rhodamine). Magnetic carbon nanotubes (MCNT), magnetic graphene oxide (MGO) and magnetic olive wood (MOW) were involved as adsorbents. The following adsorption issues were considered at various pHs: Effect of magnetic adsorbent type on Cd(II) uptake in presence and absence of Tartrazine; Effect of dye type on Cd(II) uptake by MCNT; Adsorption of organic dyes’ onto MCNT; Effect of other adsorption factors [“magnetite:CNT” mass ratio; “Cd: Rhodamine” molar ratio]. It was found that the presence of dyes caused an enhanced uptake of Cd(II) uptake by MCNT, which was attributed to suraface-dye-Cd ternary complex formation, in which Rhodamine caused the maximum Cd(II) uptake at pH 8. The maximum Cd(II) uptake conditions [using MCNT at pH 8 in (1:3) “Cd:Rhoadamine” molar ratio] gave Cd(II) adsorption capacity of 23 mg g−1. The method was re-useable, applicable on environmental waters and selective with a 20% decrease in its performance in presence of competing ions.