A novel Cd(II) ion imprinted interpenetrating polymer network (Cd(II)IIP) was prepared by free radical polymerization using alginic acid and NNMBA-crosslinked polyacrylamide in presence of initiator potassium persulphate. Cd(II)IIP showed higher capacity and selectivity than the nonimprinted polymer (NIP). The sorption capacities of Cd(II)IIP and NIP for Cd(II) ions were 0.886 and 0.663 , respectively. Kinetics studies showed that the sorption process closely agreed with a pseudosecond-order model. The thermodynamic data suggest that the sorption is a spontaneous endothermic process. Equilibrium experiments showed very good fit with the Langmuir isotherm equation for the monolayer sorption process. Cd(II)IIP exhibited good reusability, and the sorption capacity of Cd(II)IIP was stable within the first 4 cycles without obvious decrease. Also Cd(II)IIP showed almost 100% removal efficiency for Cd(II) ions in real environmental water samples, indicating that Cd(II)IIP could have wide application prospects in Cd(II) ion removal. 1. Introduction Water pollution is one of the most serious environmental problems of the present day. Water obtained from different sources is associated with a large number of impurities. Among them heavy metal toxicity is very crucial. Occurrence of toxic metals in lakes, ponds, ditch, and river water affect the lives of local people that depend on these water sources for their daily requirements [1]. Currently, anthropogenic inputs of metals exceed natural input. High levels of Cd, Cu, Pb, and Fe can act as ecological toxins in aquatic and terrestrial ecosystem [2, 3]. Cadmium, as a hazardous pollutant commonly present in the living environment, represents an important risk to human health. Cadmium and its compounds are highly toxic and exposure to this metal is known to cause cancer and targets the body’s cardiovascular, renal, gastrointestinal, neurological, reproductive, and respiratory systems. The approach of bioremediation is an innovative tool with greater potential to remove heavy metal ions in water bodies. The method of ion imprinting has become one of the fast-growing technologies that have achieved a lot of attention recently especially in the area of materials science. The IIPs are synthesized on the principle of enzyme phenomenon whereby a monomer is altered by a polymerization that takes place in the presence of a template that will be later removed to create cavities that will recognize only the analyte of interest. Also, the international agency for research on cancer has classified cadmium as a human carcinogen
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