Kinetic and thermodynamic studies of adsorption
by superparamagnetic nano iron oxide-loaded
poly(acrylonitrile-co-acrylic acid) hydrogel
Received: 27 February 2013 / Accepted: 20 June 2013 / Published online: 5 July 2013
Ó Springer Science+Business Media Dordrecht 2013
Abstract The efﬁciency of adsorption of cadmium ions from aqueous solutions by
superparamagnetic nano iron oxide-loaded poly(acrylonitrile-co-acrylic acid)
hydrogel has been investigated. The effect of equilibration time, amount of adsor-
bent, temperature, adsorbate concentration, and pH was studied by use of a batch
system. The copolymer was magnetized in situ and the size, phase identiﬁcation,
morphology, and coating of magnetic nanoparticles were characterized by TEM,
AFM, XRD, and FTIR analysis respectively. The sorption data were analyzed and
ﬁtted to linearized equations of the Langmuir, Freundlich, and Temkin isotherms.
The kinetics of sorption were analyzed by use of pseudo-ﬁrst-order and pseudo-
second-order kinetic models. Kinetic data, rate constants, equilibrium sorption
capacities, and related correlation coefﬁcients for each kinetic model were calcu-
lated and are discussed. Thermodynamic data DG°, DH°, and DS° were evaluated. It
was found the sorption process was feasible, spontaneous, and exothermic in nature.
This hydrogel was an efﬁcient adsorbent for removal of Cd
ions from water
([98 % removal) and could be regenerated efﬁciently ([99 %).
Keywords Superparamagnetic PANA Á Hydrogel Á Isotherms Á Kinetics Á
Pollution of water bodies by toxic heavy metals is a serious environmental problem.
The progressive increase of industrial technology has resulted in a continuous
A. Tiwari (&) Á N. Sharma
Department of Chemistry, Government V.Y.T. Post Graduate Autonomous College, Durg,
Chhattisgarh 491001, India
e-mail: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
Res Chem Intermed (2015) 41:2043–2062