Removal of proflavine sulphate dye from wastewater using tea-bag tissue as an adsorbent

Proflavine sulphate dye is acknowledged as a hazardous substance detrimental to both human health and the environment. Consequently, our primary objective was to put forth a straightforward, effective, and economical method for purifying water contaminated with proflavine sulphate dye. The efficacy of a tea-bag tissue (TBT) that utilizes a membrane made of cellulosic material has been evaluated for its potential as an adsorbent to remove proflavine sulphate from water. This assessment was conducted using pH 8 for the batch equilibrium approach. The adsorption investigations encompassed variables such as contact time, adsorbent mass, adsorbate concentration, and pH (with the determination of the adsorbent's pH at the point of zero charge, pHPZC). These studies indicate that a TBT is a promising membrane for effectively removing proflavine sulphate dye from water at a pH of 8. This conclusion is supported by its notable uptake capacity (%), rapid adsorption rate (achieving equilibrium within approximately 60–70 s), and high regeneration efficiency (approximately 86.98 %). The latter suggests the reversibility of the sorption process without compromising binding efficiency. The isothermal characteristics and adsorption kinetics of proflavine sulphate on the surface of the TBT were explored in relation to temperature variations and the initial mass of the TBT. The findings indicate a strong correlation between the experimental adsorption data and both the Langmuir and Freundlich isotherm equations. Moreover, the adsorption process is most accurately described by the pseudo 2nd order model. Molecular electrostatic potential (MEP) maps for cellulose and proflavine sulphate, based on density functional theory (DFT) calculations, were examined to elucidate charge-dependent properties and potential interactions between the adsorbent (cellulose) and the adsorbate (proflavine sulphate). According to the data, the main interaction between the two compounds is caused by their H bonds with one another.