Abstract:
In recent years with the rapid economic globalization, pollution by industries and agriculture has
increased, which results in decrease in the quality of ground and surface water. Pollution by heavy
metals has become a serious health issue worldwide due to their non biodegradable and persistent
nature. Heavy metals represent one of the most important kinds of pollutants, causing serious
threats to the ecological balance. Thus, their removal from aqueous solution is a major
environmental concern worldwide. The process of adsorption—being very simple, economical,
and effective—is widely applied for the decontamination of wastewaters from heavy metals. The
particle size, functional groups, and surface morphology of nickel-doped zinc oxide-polyaniline
nanocomposite were characterized by XRD, FT- IR, and SEM, respectively. The concentration of
Cr (VI) was determined by using Carry UV-Visible spectroscopy.
The variables affecting the adsorption process, initial adsorbate concentration, pH, adsorbent
dosage and contact time were optimized. Equilibrium adsorption isotherm and kinetic were also
studied. The analysis of variance (ANOVA) revealed that all the variables studied had significant
effects on the removal efficiency of Cr (VI). The obtained data showed that 4 mg/L initial Cr(VI)
concentration, 4 solution pH, 0.7 g adsorbent dosage and 90 min contact time resulted in 95.6%
adsorption. Equilibrium adsorption isotherm and kinetic studies showed that Langmuir isotherm
and pseudo-second-order kinetic model fitted well to the experimental data.
