Rapid adsorption and detection of copper ions in water by dual-functional ion-imprinted polymers doping with carbon dots

Abstract

The pollution of heavy metals such as copper ions to water body is still serious, and the discharge of sewage containing heavy metals into the environment will cause damage to soil and even human body. Herein, poly(glycidyl methacrylate-co-polyethylene glycol dimethacrylate) was applied as matrix, methacrylic acid (MAA) as monomer, diphenylsemicarbazide (DPC) as ligand. The spherical copper ion imprinted polymer (Cu-IIP-A) was synthesized by atom transfer radical polymerization (SI-ATRP). Yellowish fluorescent carbon dot (CD) containing amino groups was prepared from tryptophan and o-phenylenediamine and added to during the preparation of Cu-IIP. A new copper ion imprinted polymer was acquired and assigned as CD@Cu-IIP-A. For comparison, amorphous Cu-IIP particles were prepared with the same raw materials by bulk polymerization, which were named as Cu-IIP-B and CD@Cu-IIP-B, respectively. Under the same conditions, the dispersion of CD@Cu-IIP-A in water was much better than that of CD@Cu-IIP-B, and the maximum adsorption capacity reached 85.6 mg g−1, which was larger than that of CD@Cu-IIP-B (66.05 mg g−1), and only slightly lower than that of Cu-IIP-A (91.9 mg g−1). CD@Cu-IIP-A only takes 30 min to reach adsorption equilibrium and has a good fluorescence quenching effect on copper ion at 80–780 μmol L-1. These indicated that CD@Cu-IIP-A exhibited both fluorescence detection of CD and selective adsorption functions of IIP, which can satisfy both detection and efficient enrichment of copper ion in water.