The development of new adsorbent has rapidly increased in order to overcome the problem
of waste water treatment from heavy metal pollution. The ability of nickel (II)-ion imprinted
polymer (Ni-IIP) as an alternative adsorbent for the removal of nickel ion from aqueous has
been investigated. The Ni-IIP was prepared via bulk polymerization by using functional
monomers; methylacrylic acid (MAA) with picolinic acid as a co-monomer. Nickel ion was
used as template, AIBN as initiator and EGDMA as cross-linking agent. Non-imprinted control
polymer (NIP) was prepared in the same manner as Ni-IIP but in the absence of nickel
ion. The resultant of Ni-IIP and NIP were characterized by using Fourier Transform Infrared
(FTIR) spectroscopy and Scanning Electron Microscope (SEM). Result showed that, the adsorption
of nickel ion onto Ni-IIP increased as the adsorbent dosage increased and contact
time is prolonged. The adsorption isotherm model for Ni-IIP and NIP were fitted well with
Freundlich and Langmuir, respectively. Kinetic study for both Ni-IIP and NIP were followed
the pseudo-second order, indicates that the rate-limiting step is the surface adsorption that
involves chemisorption. Selectivity studies showed that the distribution coefficient of Ni2+
was higher compared to Zn2+, Mg2+ and Pb2+. The present work has successfully synthesized
Ni-IIP particles with good potential in recognition of Ni2+ ions in an aqueous medium.
A paradigm shift in supramolecular chemistry has drawn our attention to produce coordination
polymers for anion separation. In this approach, we have successfully synthesized a
one dimensional coordination polymer from combination of U-shaped diamide ligand, namely
N,N -2,6-bis(4-pyridylmethyl)pyridine dicarboxamide (L1) and Zn(NO3)2 in methanol. This
product is obtained as single crystal with formula molecule given by elemental analysis as
{[Zn(L1)2(H2O)2](NO3)2.4H2O}n. In this account, we also describe supramolecular interactions
between this coordination polymer with two selected anions, nitrate and chromate
using combination of experimental and theoretical studies. Observation via FTIR spectra
indicates the presence of two distinctive peaks for Cr-O (931 cm−1
) and N-O (1384 cm−1
)
confirming encapsulation of chromate and nitrate anions in the receptor. X-ray crystallography
reveals the interaction between NH amide with the anions as expected. As resulted
by Gaussian, coordination polymer with nitrate anion is found more stable compared to
chromate with interaction energy 342.2729 kJ/mol.