Selective sequestration of perfluorinated compounds using polyaniline decorated activated biochar

Poly- and perfluorinated compounds (PFCs) in wastewater could induce the poisonous effects to the living beings throughout the world. In this present investigation, polyaniline (PANI) decorated activated biochar (AB) hybrid composite ([email protected]x%PANI, x = 0%, 25%, 50%, 75%, and 100% of PANI) was fabricated for PFCs adsorption via in situ chemical oxidation and co-precipitation with calcination. The physical and chemical properties of [email protected]x%PANI before and after adsorption were characterized by FTIR, PXRD, XPS, FE-SEM with EDX, HR-TEM, 13C NMR, and TGA analysis. Batch experiments for the effect of contact time, initial PFCs concentration, solution pH, and co-existing cations were conducted for the maximum adsorption capacity of as-synthesized adsorbents. The [email protected]%PANI hybrid composite exhibited higher adsorption capacity for the removal of perfluorooctanoic, perfluorooctanesulfonic, and perfluorohexanesulfonic acids than powdered activated carbon, AB, PANI, [email protected]%PANI, and [email protected]%PANI. The adsorption isotherm and kinetic results demonstrated that the adsorption system using [email protected]%PANI hybrid composite followed pseudo-second-order and Langmuir isotherm models. The PFCs adsorption by [email protected]%PANI was mainly governed by various interaction forces such as hydrogen bonding, electrostatic attraction, hydrophobic interaction, and surface complexation in the presence of co-existing cations. These findings shed light on how to selectively eliminate PFCs from wastewater.