Treatment of wastewater containing alizarin red dye: development and application of magnetic chitosan as a natural eco-friendly material

The efficient removal of harmful dyes from wastewater, employing green methods, is a subject of growing interest. Anthraquinone dyes alizarin red (AR) S and methyl orange (MO) were used as model pollutants in this investigation, and magnetic chitosan particles were used to extract them from aqueous solution. SEM-EDX, XRD, FTIR ATR, and TGA DSC were used to examine the physicochemical, thermal, and morphological properties of the synthesized material. The effect of pH, dye concentration, duration, and adsorbent loading on dye degradation was examined. After adsorption, the material could be easily separated with the assistance of an external magnet. The selective adsorption of alizarin red S dye to methyl orange was studied in single and binary solutions. The dye uptake capacity provided by the use of the pseudo-second-order model is higher as compared to the pseudo-first order. The dye was adsorbed at 201.5 mg/g for 120 min. The batch adsorption followed the Freundlich isotherm (R-2 = 0.995) with alizarin red adsorption being endothermic with the presence of multimolecular layer adsorption. Desorption efficiency decreases to 90% after the first cycle. For repeated usage, the material proved to be extremely stable and easy to recycle. The adsorption mechanism of AR and MO dye removal by magnetic chitosan adsorbent is proposed. [GRAPHICS] .

Automated summary

This study investigated the efficient removal of harmful dyes from wastewater using magnetic chitosan particles. The synthesized material exhibited high dye uptake capacity and could be easily separated and recycled with the assistance of an external magnet. The study also examined the factors influencing dye degradation and proposed the adsorption mechanism of the magnetic chitosan adsorbent.