Design and characterization of PANI/starch/Fe₂O₃ bio composite for wastewater remediation

A new synthesized polyaniline/starch/hematite bio composite (PANI/S/Fe₂O₃ BC) has been studied as an effective material for on-site water remediation. PANI/S/Fe₂O₃ BC was developed by combining the techniques of co-precipitation and interfacial polymerization in the presence of aqueous starch solution in an acidic medium under ultrasonic irradiation. The nano-morphologies and structures of the designed PANI/S/Fe₂O₃ BC were evaluated by various techniques relative to PANI and Fe₂O₃ nanoparticles. In single and multiple systems, PANI/S/Fe₂O₃ BC was evaluated as a possible adsorbent for different heavy metals, including As³⁺, Zn²⁺, and Co²⁺, relative to PANI and Fe₂O₃ nanoparticles. In terms of pH value, operating temperature, initial heavy metal concentration, contact time, adsorbent dose and competitive ions in the solutions, the adsorption process was optimized. For 92% overall adsorption of Co²⁺ and 100% overall adsorption of both As³⁺ and Zn²⁺, the adsorption equilibrium was achieved within 60 and 120 min, respectively. In addition, adsorption thermodynamic analysis shows that the As³⁺ ions adsorption process was not random and the pseudo-second-order fitted with experimental results. Moreover, PANI/S/Fe₂O₃ BC was evaluated as an antibacterial agent against Gram-negative bacteria (Salmonella typhimurium) and Gram-positive bacteria (S. aureus, Methicillin-Resistant Staphylococcus, Aureus Clinical isolate and Bacillus subtilis). The reported performances indicated that the PANI/S/Fe₂O₃ BC is a potent candidate for industrial water bioremediation.