Abstract
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•GMA-DETA is very efficient for Hg recovery from complex solutions.•Fast kinetics is observed due to the small size of magnetic particles.•Mercury was successfully sorbed from industrial effluents.•Mercury can be desorbed and the sorbent recycled for at least 4 cycles.
A composite sorbent (MGMA) was synthesized by coating a magnetite core with glycidyl methacrylate-based polymer, further grafted with diethylenetriamine (DETA). The absence of coercivity and remanence in VSM analysis confirms that the material has super paramagnetic properties that make it readily separable from the liquid phase applying external magnetic field. The sorbent (MGMA-DETA) was tested for Hg(II) recovery from aqueous solutions (of increasing complexity). The separation of Hg(II) from multi-metal solutions was tested at different pH values. The impact of counter ions on metal sorption was also tested at different pHs. Sorption mechanisms explained the different effects of counter ions (in relation with metal speciation) and also the relative selectivity of the sorbent for Hg(II) over other base metals. Uptake kinetics and sorption isotherms were modeled with the pseudo-second order rate equation and the Langmuir equation, respectively. The thermodynamic parameters have been calculated. The sorbent was successfully tested for Hg(II) removal from two industrial effluents (from chlor-alkali industry and from mercury-oxide manufacturing). The sorbent could be recycled for at least 4 cycles of sorption/desorption. This means that the magnetic sorbent is a promising material for the efficient and selective removal of mercury from complex solutions.