Use of a novel low-cost adsorbent PANI@Clay composite to effectively remove OG dye from wastewater: Insights from isotherm kinetic and thermodynamic modeling, investigation using density functional theory DFT/MC/MD

The purpose of this research was to determine if a natural clay treated with Polyaniline (PANI) might be used to effectively and affordably remove of anionic dyes from aqueous solutions, with a focus on Orange G dye (OG). After combining PANI with natural clay. We created a Polyaniline-clay composite after analyzing it with FTIR, XRD, SEM and EDS of the (PANI@Clay). Using batch adsorption tests, we compared the performance of PANI@Clay and raw clay at removing OG from aqueous solutions as a function of contact duration (10-360 min), initial concentration (50-500 mg/L), temperature (293-318 K), and pH (2-12). Results showed that PANI@Clay had a maximum equilibrium adsorption capacity of 67.35 mg/g, while raw-clay only managed 47.62 mg/g. Pseudo second-order and Langmuir models were both good fits for the kinetic behavior and the isotherms. According to the Gibbs energy and other thermodynamic parameters, OG adsorption onto PANI@Clay and raw clay was a spontaneous process that became more energy-intensive as temperature was raised. Overall, the results of this work show that PANI@Clay offers promising use as an adsorbent for cleaning water supplies of cationic dyes it explains the processes and thermodynamic features of OG adsorption, which were previously unknown onto PANI@Clay and raw clay. The structure of the OG dye was optimized at the B3LYP functional with 6-311+g(d,p) set in aqueous solution. The global and local chemical reactivity descriptors were calculated to suggest a suitable mechanism for removal process.