A Cr(VI)-imprinted-poly(4-VP-co-EGDMA) sorbent prepared using precipitation polymerization and its application for selective adsorptive removal and solid phase extraction of Cr(VI) ions from electroplating industrial wastewater

A Cr(VI)-imprinted-poly(4-VP-co-EGDMA) (IIP) was proposed to be used in the process of selective extraction of low concentration of Cr(VI) ion from aqueous solution. The polymer was synthesized by using Cr(VI) ion as a template, 4-vinylphiridine (4-VP) as complexion agent and monomer, ethylene glycol dimethyl acrylate (EGDMA) as cross-linker, benzoyl peroxide (BPO) as initiator and ethanol/acetone as a porogen. Non ion-imprinted-poly(4-VP-co-EGDMA) (NIP) as a control polymer was prepared too. The synthesis was conducted by using precipitation polymerization method. The prepared of IIP unleached, IIP leached and NIP were characterized by XRD, FTIR, SEM-EDX and BET-BJH instrument. Based on the characterization data, it can be found that all of this imprinting material have a micro and mesopore structures. The effect of sorbent dosage, pH, contact time and temperature on Cr(VI) adsorption from aqueous solution were investigated. The result shows that the adsorption of Cr(VI) ion was highest at pH 2 with 30 min contact time at 313 K with an initial concentration of Cr(VI) 14 mg/L. The selective studies shows that the IIP material was a very selective to adsorp Cr(VI) even in water was found interfering ion such as Ni(II) and Cr(III) respectively. Kinetic and isotherm modeling were also studied by using 5 models in each. The result of modeling kinetic shows that Cr(VI) adsorption fit with the Pseudo-second-order model while modeling isotherm followed the Freundlich model. The application of this material to adsorb Cr(VI) from electroplating industrial waste which reaches 96% and the reusability testing also shows that this adsorbent has good stability even though it was used 10 times repeatedly.