Adsorption of Acid orange 7 dyes from aqueous solution using Polypyrrole/nanosilica composite: Experimental and modelling

The adsorption of Acid orange 7 (AO7) by Polypyrrole/nanosilica composite (PPN/SiO2) was studied and various parameters have been investigated, more than 99.4% of the adsorption efficiency was obtained under the optimal conditions (PPN/SiO2 mass = 1 g/L, contact time = 90 min, Initial AO7 concentration = 10 mg/L, shaking speed = 200 rpm and temperature = 328 K and pH = 3).PPN/SiO(2)specifications were determined using FTIR, XRD, TGA, pH(zpc),TEM and SEM analysis. The kinetic data were fitted by the pseudo-second-order kinetic; the rate constant K increased when temperature increased indicating the adsorption was endothermic in nature. The studies related to the adsorption mechanism illuminated that the AO7 adsorption process was complex and obeyed both surface adsorption and particle diffusion. Moreover, based on the results, the adsorption happens through film diffusion at low concentrations while the particle diffusion is the rate-determining step at higher concentration. The isotherm equations showed that the equilibrium data followed more than the Langmuir isotherm with a maximum adsorption capacity of 181.4 mg/g. The thermodynamic parameters were calculated, and their negative value of Delta G degrees and positive value of Delta S degrees and Delta H degrees showed that the adsorption was spontaneous and endothermic.

Automated summary

The adsorption of Acid orange 7 (AO7) by Polypyrrole/nanosilica composite (PPN/SiO2) was extensively studied, and it was found that the adsorption efficiency exceeded 99.4% under certain conditions. The specifications of PPN/SiO2 were characterized using various analysis methods, and the adsorption mechanism was clarified. The experimental results demonstrated that the adsorption process was complex, involving both surface adsorption and particle diffusion. Additionally, it was discovered that film diffusion occurred at low concentrations, while particle diffusion controlled the adsorption process at high concentrations. Thermodynamic parameters indicated that the adsorption was spontaneous and endothermic.