Synergistic Power of Polyaniline Decorated <i>Rauvolfia tetraphylla</i> Fruit Biochar Hybrid in Smart Eriochrome Black T Remediation and Antibacterial Application

Polymer-decorated composites for wastewater purification and bactericidal applications are of interest. Accordingly, the polyaniline decorated Rauvolfia tetraphylla fruit biochar (PANI@RTFB) composite was synthesized for Eriochrome black T (EBT) scavenging and bactericidal application. PANI@RTFB was characterized through BET surface area, SEM-EDX, FTIR, pHzpc, and PXRD. A porous (BET surface area of 6.741 m2/g), quasi-crystalline nature, and COVID-19 virus-like architecture were seen from SEM. Polyaniline coating was confirmed from FTIR, and pHzpc was found to be 8.59. A maximum removal of 93.37% EBT from simulated and 52.68% from wastewater was achieved within 60 min with 30 mL of 20 mg/L EBT, pH 7, and 298 K temperature. With an uptake capacity of 110.236 mg/g, PANI@RTFB enjoys an edge over reported adsorbents. The Langmuir (R2=0.996) and the pseudo-second-order (R2 = 0.999) models were fitted best. The endothermic (ΔH = 16.302–18.188 kJ/mol) and favorable (ΔG = −1.182 to −5.346 kJ/mol) uptake occurred through H-bonding, electrostatic, and π-π interaction mechanisms. 50% methanol regenerates spent in up to 75.75%. The waste disposal issue was addressed by conversion to a new adsorbent with 64% efficiency. At a 20 mg/mL dose, PANI@RTFB reduced Staphylococcus aureus and Escherichia coli colonies by 56.90% and 73.17%. The PANI@RTFB ruptured the cell membranes of bacteria through electrostatic and hydrophobic interactions.