Removal of Cadmium(II) from Wastewater Using Novel Cadmium Ion-Imprinted Polymers

Abstract

Cadmium ion-imprinted polymers (Cd-IIP) were synthesized by precipitation polymerization using a complex of dithizone and cadmium as a template. The saturation adsorption capacity of the Cd-IIP is two times that of the nonimprinted polymers (Cd-NIP). Homogeneous binding sites are confirmed by the Langmuir isotherm. The adsorption kinetics fit a pseudo-secondorder model well; and the adsorption equilibrium time is only approximately 20 min. The effect of coexisting ions on the Cd(II)-IIP and NIP were investigated by competing with Pb(II), Zn(II), Co(II), and Cu(II), and the ratio of relative selectivity coefficients was greater than 1.68. Thermodynamic parameters indicated that Cd(II) adsorption over IIP and NIP was a spontaneous and exothermic process. The enthalpy changes in different temperatures and adsorption energy are lower than −20.0 and 8 kJ/mol; respectively. These indicate that the adsorption process may be dominated by physisorption. The Cd-IIP was used for five cycles with a small decrease in adsorption capacity, which validated a significant potential of Cd-IIP in wastewater treatment.

Activated biochar derived from pomelo peel as a high-capacity sorbent for removal of carbamazepine from aqueous solution

“…K d is the thermodynamic equilibrium constant, which calculated by plotting ln(Q e /C e ) vs. Q e and extrapolating to zero Q e . 41,42 The values of DH 0 and DS 0 can be directly obtained from the slope and intercept of the plot ln K d as a function of 10 3 /T of linear (Fig. S5 †).…”

Synthesis of multi-ion imprinted polymers based on dithizone chelation for simultaneous removal of Hg2+, Cd2+, Ni2+ and Cu2+ from aqueous solutions

“…On [21][22][23] and has excellent selectivity advantages due to its -SH and -NH-functional groups. 9,12,[21][22][23][24][25] The traditional view expects a tautomeric equilibrium for dissolved dithizone between the ketone form (Ph-NH-NH]CS-N]N-Ph) and the enol form (Ph-NH-N]C(SH)-N]N-Ph).…”

“…9,12,[21][22][23][24][25] The traditional view expects a tautomeric equilibrium for dissolved dithizone between the ketone form (Ph-NH-NH]CS-N]N-Ph) and the enol form (Ph-NH-N]C(SH)-N]N-Ph). As pH increases, it is easy for S with a lone-pair electron to bind with H to form a thiol group, which would easily form a complex with metal ions.…”

Optimization of cadmium adsorption from aqueous solutions by functionalized graphene and the reversible magnetic recovery of the adsorbent using response surface methodology

“…Heavy metals, the most common pollutants found in wastewater, are considered with great concern because of their extreme toxicity even at a trace level. Cadmium is a metal of most toxicological concern because of its bioaccumulation and nonbiodegradability, causing negative effects on the heart, lungs, bones, and especially, the kidneys . Cadmium is widely used in metal plating, cadmium‐nickel batteries, phosphate fertilizers, pigments, alloy industries, and many other branches of industry …”