Polyaniline-encapsulated quartz sand as an adsorbent composite for Orange G dye removal from aqueous solution: Experimental and computational study.

The presented discovery provides a long-term strategy for successfully utilizing quartz sand (QS) as a low-cost, efficient, and environmentally friendly adsorbent. To improve the adsorption capacity and efficiency, a new chemical strategy was used to coat the QS particles with polyaniline (PANI), creating a hybrid material composite (QS@PANI). The prepared composite's ability to effectively remove Orange G dye (OG) from aqueous solutions was investigated through a series of batch adsorption experiments. The highest removal efficiency was due to the synergistic effect of the QS and the PANI, which favors electrostatic interaction, π-π interaction, and hydrogen bonding due to the nitrogen atoms in their conjugated chains. Adsorption kinetics were described by the pseudo-second-order, and Elovich models, while equilibrium capacity was described by the Langmuir adsorption model. Interestingly, after six repeated cycles, the composites unveiled a high removal proficiency >82% at different pH (2–8) of the solution and possessed an excellent adsorptive property, providing a cost-effective material for decolorization applications. Density functional theory (DFT) calculations and molecular dynamics simulations were utilized to elucidate the adsorption mechanism. The results showed that Orange G adsorption on QS@PANI occurs via a physisorption process. This research not only provided a structure-function relationship for PANI-QS organic-inorganic composite material assemblies, but it also provided an encouraging framework for the long-term advancement of water purification technology. [Display omitted] [ABSTRACT FROM AUTHOR]