Removal of Anionic Dyes from Water by Potash Alum Doped Polyaniline: Investigation of Kinetics and Thermodynamic Parameters of Adsorption

Abstract

Polyaniline was synthesized by the oxidative polymerization method by using ammonium persulfate as an oxidant. The positive charge in the backbone of the polymer was generated by using Potash alum as a dopant. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray fluorescence (XRF), and X-ray diffraction (XRD) techniques were used for characterization of doped polyaniline. The doped polyaniline can be used for selective adsorption of various dyes (selectively sulfonated dyes) from aqueous solution. Adsorption studies regarding the effect of contact time, initial dye concentration, pH, doses of adsorbent, and temperature on adsorption kinetics were investigated. The influence of other anions like Cl(-), NO3(-), and SO4(2-) on the adsorption density of dyes onto doped polyaniline was also explored. Langmuir isotherm and pseudo-second-order kinetics were found to be the most appropriate models to describe the removal of anionic dyes from water through adsorption. Thermodynamic parameters such as free energy (ΔG(0)), enthalpy (ΔH(0)), and entropy (ΔS(0)) changes were also evaluated. The interaction of dyes with doped polyaniline was also investigated by FTIR and UV spectroscopy.

Comparative Study of the Adsorption of Acid Blue 40 on Polyaniline, Magnetic Oxide and Their Composites: Synthesis, Characterization and Application

“…After the adsorption of AB40 (Figure 1d), the morphology of PANI changes to a cauliflower shape with some needle-like structures present on the surface. Such a change in morphology was also reported during the adsorption of anionic dyes on PANI doped with Potash Alum [51]. Figure 1e shows an SEM image of PANI/Fe 3 O 4 composites.…”

Preparation of NiFe2O4/polythiophene nanocomposite and its enhanced adsorptive uptake of Janus green B and Fuchsin basic from aqueous solution: Isotherm and kinetics studies

“…In recent past, ferrite‐based nanocomposites have drawn significant attention on account of their potential application as adsorbents for removal of dyes from wastewater . In context of polymer nanocomposites, conducting polymers are of considerable interest because of their high conductivity, environmental stability, cost effective monomer, ease of synthesis and unique physicochemical properties . However, only a few studies concerning the adsorptive removal of pollutants from aqueous solution using conducting polymers‐based ferrite nanocomposites has been published.…”

Acid green crystal-based in situ synthesis of polyaniline hollow nanotubes for the adsorption of anionic and cationic dyes

“…The most important methods available for the removal of dyes from wastewater are chemical coagulation, Fenton oxidation, ozonation, membrane processes and adsorption. 1,2,5 Adsorption is an effective technique that is widely used for the treatment of dyes in wastewater 1,4,6 due to its ease of use and inexpensive nature. 2 Due to its high adsorption efficiency, activated carbon has been extensively used as an adsorbent, but a problem lies in its high usage costs, 2,3,6 which led many researchers to look for inexpensive and locally available alternative adsorbents to render the adsorption process economically feasible.…”

“…2 Due to its high adsorption efficiency, activated carbon has been extensively used as an adsorbent, but a problem lies in its high usage costs, 2,3,6 which led many researchers to look for inexpensive and locally available alternative adsorbents to render the adsorption process economically feasible. 5 Polyaniline (PANI) has attracted much attention due to its unique properties and advantages, such as its easy synthesis, good environmental stability and low cost. 3,[7][8][9][10][11] PANI can exist in three different isolable oxidation states at the molecular level; the leucoemeraldine, emeraldine and pernigraniline states.…”

“…While conventional PANI powder shows a limited adsorption of dyes, [14][15][16] nanostructured PANI has an improved adsorption capacity for dyes. 5 As a form of PANI nanostructure, PANI nanotubes have been used effectively for the removal of MB as a cationic dye and acid green (AG) as an anionic dye from aqueous solutions. 8,17 PANI-NTs base/silica composites and nanostructured crosslinked PANI were found to have little adsorption capacity for dyes.…”