Removal of heavy metal ions from wastewater by carbon nanotubes (CNTs)


This work is an attempt to remove cadmium (II) from wastewater by adsorptionon multi-walled carbon nanotubes (MWCNTs) and functional group of carbonnanotubes (fMWCNTs) by using the batch process system and continuous reactor.In the batch reactor, the main variables that govern process efficiency such as theinitial Cd (II) concentration, MWCNTs dose, contact time, stirring speed, and pHwere studied. The experiments revealed that the amount of cadmium absorption(II) was higher on the increasing fMWCNTs dose and stirring speed. In addition,it decreased significantly with a decrease in the initial concentration of cadmium.The optimum values for the ratio of the acidic function in solution 5.5, theabsorbent dose (fMWCNTs) 1 g in 100 ml of Cd (II) solution, and the contact timewas 30 minutes, in addition to C0 of 125 mg per liter of the cadmium ion withmixing speed (stirring) 100 rpm, these are the optimum values by which thecadmium ion removal efficiency was obtained for no more than 99%. Equilibriumdata were better explained by the Freundlich isotherm model which was convertedinside what was achieved with 30 minutes of Cd + 2