GREEN SYNTHESIS OF PANI/MAGNETITE ADSORBENT USING CROT ON MACROSTACHYUS LEAF EXTRACT FOR REMOVAL OF RHODAMI NE BLUE DYE FROM AQUEOUS SOLUTION.

Abstract

In this study, a green synthesis approach was employed to create adsorbent consisting of polyaniline (PANI) and magnetite (Fe₃O₄) nanoparticles using an aqueous extract of Croton macrostachyus leaves. To characterize the structural, chemical, and optical properties of the synthesized materials, several analytical techniques were employed. The XRD results indicated that the average particle size of the PANI/Fe₃O₄ adsorbent was approximately 14 nm, suggesting that the material consisted of nanoscale particles, which is crucial for improving the surface area and reactivity of the adsorbent. UV-DRS analysis revealed that the nanocomposite exhibited broad absorbance peaks between 700 and 800 nm. FTIR spectroscopy confirmed the presence of functional groups corresponding to PANI/Fe₃O₄, PANI and Fe₃O₄, and the phytochemicals in the Croton macrostachyus leaf extract. The adsorptive efficiency of each material was evaluated under varying experimental conditions, such as pH, adsorbent dose, contact time, and initial dye concentration. The results showed that the optimum conditions for dye removal occurred at a pH of 10, an adsorbent dose of 80 mg, a contact time of 50 minutes, and an initial dye concentration of 10 mg/L. Under these conditions, the dye removal efficiencies were 91.22% for PANI, 96.97% for Fe₃O₄, and 99.91% for the PANI/Fe₃O₄ adsorbent, demonstrating exhibited superior dye removal performance. To further understand the adsorption behavior, adsorption isotherm models were applied. The results indicated that the adsorption of Rhodamine Blue dye onto all three adsorbents (PANI, Fe₃O₄, and the nanocomposite) was best described by the Langmuir isotherm, suggesting that the adsorption occurred via a monolayer adsorption process with uniform adsorption sites. In contrast, the Freundlich isotherm, which models heterogeneous adsorption, did not fit as well, indicating that the adsorption sites on the materials were relatively uniform. Additionally, the adsorption kinetics were found to follow the pseudo-second-order model, suggesting that the rate-limiting step of the dye removal process was chemical adsorption. The findings from this study underscore the potential of the green-synthesized PANI/Fe₃O₄ adsorbent as a highly effective and environmentally friendly adsorbent for the removal of organic dyes from wastewater.