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 com-posite (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, z-z 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.

Automated summary

This study presents a long-term strategy for utilizing quartz sand as an efficient and low-cost adsorbent by coating it with polyaniline. The resulting hybrid material (QS@PANI) showed excellent performance in removing Orange G dye from aqueous solutions due to the synergistic effect of the quartz sand and polyaniline. The adsorption process was explained through kinetics and equilibrium models, and the material exhibited high removal efficiency even after multiple cycles, making it a promising material for decolorization applications.