Selective electrosorption of trace Pb(II)from drinking water by a novel energy-recovery & adsorption-enhanced capacitive deionization system

In this work, an energy-efficient capacitive deionization (EACDI) system with energy-recovery and enhanced adsorption capacity was firstly built by using metallocene-doped MoS 2 /CNT (mFc@MoS 2 /CNT). The structures and morphologies of the porous materials including single walled carbon nanotube (SWCNT), MoS 2 /CNT and mFc@MoS 2 /CNT were investigated by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffractometer (XRD), Raman spectra and N 2 adsorption-desorption tests, and the performance of EACDI system on the removal of Pb 2+ and Cd 2+ were evaluated by electrosorption tests. The results suggest that this EACDI system shows higher adsorption capacity on the removal of heavy metal ions at the concentration level of mg/L, with respect to traditional capacitive deionization (CDI). Moreover, this new method shows good selectivity and high energy effectiveness on the separation of trace Pb 2+ with the adsorption efficiency of 96 % at 10 μg/L level and an energy consumption of 0.98 kJ/m 3 with 24.2 % energy recovery. As a result, this research reveals an advanced electrosorption method to purify the drinking water polluted by trace heavy metals with the advantage of low cost and high energy efficiency.