Nandini Venkat Iyer; Jayant A Kher; Shekhar D Bhame
Abstract
The present study features the synthesis of Dodecylbenzene sulphonic acid-doped polypyrrole tungsten oxide (PPy-WO3) nanocomposites and its photocatalyic studies on Methylene Blue (MB). The nanocomposites of PPy with a very low concentration of WO3 were prepared using 0.05 to 0.3 wt.%, of WO3 nanoparticles. ...
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The present study features the synthesis of Dodecylbenzene sulphonic acid-doped polypyrrole tungsten oxide (PPy-WO3) nanocomposites and its photocatalyic studies on Methylene Blue (MB). The nanocomposites of PPy with a very low concentration of WO3 were prepared using 0.05 to 0.3 wt.%, of WO3 nanoparticles. The composites were characterized by using-ray Diffraction, FTIR and FESEM for phase identification, morphological studies. The electrical conduction of the nanostructured materials at room temperature exceeded that of PPy, with the electrical conductivity increasing linearly with higher WO3 concentrations. The band gap for the nanocomposite was found to be 2.12eV. The PL spectra substantiated the adequate segregation of charge carriers photoexcited in the samples. The nanocomposites were tested as photocatalysts for the degradation of methylene blue dye (MB). A two-step mechanism has been propsed for dye removal: adsorption (in the absence of UV light) and photodegradation on the photocatalyst surface (in the presence of UV light). The maximum removal efficiency for methylene blue dye was 98.31% in UV light for 0.16 g/L of the 0.3 wt.% PPy- WO3 nanocomposite, with a dye concentration of 5 mg/L. The addition of p-benzoquinone (*O2- scavenger) contributed to a significant decrease in the photodegradation efficiency of the catalyst, i.e.,63.21%, and thus can be believed as the main active species for the degradation of the methylene blue dye.
Marjan Tanzifi; Marzieh Kolbadi nezhad; Kianoush Karimipour
Abstract
The present work seeks to investigate the ability of polypyrrole/titanium dioxide nanocomposite to adsorb cadmium ions from aqueous solution. The impact of various experimental conditions, including solution pH, adsorbent dosage, adsorption time and initial concentration on the uptake of cadmium were ...
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The present work seeks to investigate the ability of polypyrrole/titanium dioxide nanocomposite to adsorb cadmium ions from aqueous solution. The impact of various experimental conditions, including solution pH, adsorbent dosage, adsorption time and initial concentration on the uptake of cadmium were studied. The adsorption kinetic was studied with the first-order, second-order, pseudo-first-order, pseudo-second-order and Morris–Weber models. The results revealed that adsorption process is controlled by pseudo-second-order model which illustrated that the adsorption process of cadmium is chemisorption-controlled. The adsorption capacity obtained from this model is 20.49 mg/g which close to the experimental value. The study yielded the result that when the initial concentration of the solution changed from 20 mg/l to 120 mg/l, the adsorption capacity increased from 0.99 to 24.52 mg/g. Further, Langmuir, Freundlich and Temkin isotherm models were applied to investigate the adsorption isotherm. Based on the results of the adsorption isotherm, Freundlich isotherm proved to be the best fit with the experimental data. Also, the morphology, chemical structure and thermal stability of adsorbent were studied by using SEM, EDX, FTIR, and TGA.
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