Adsorption is an effective process for humic acid removal; however, disposing the spent adsorbents creates secondary waste to the environment. Hence, this study aims to investigate the feasibility of using polyaniline (PANI, a conductive polymer) to adsorb humic acid. Later on, possibility to recycle the spent PANI as electrical conductor is evaluated. The PANI was found to be 352.96 nm in size and exhibits the N-H functional group. Application study showed that the adsorption efficiency increased from 49.3% to 89.5% when the initial concentration of humic acid increased from 50 mg/L to 200 mg/L. Meanwhile, the increase in the PANI dosage successfully enhances humic acid removal owing to the existence of more adsorbing sites. The spent PANI was then deposited onto a flexible sheet and tested for its electrical conductance. Interestingly, the spent PANI-deposited sheet was found to exhibit lesser conductance (6.94 x 10-5 S) than the fresh PANI-deposited sheet (1.03 x 10-3 S). Also, the magnitude of electrical conductance further reduced with the increase in the amount of humic acid adsorbed onto the PANI. Apparently, the adsorbed humic acid has shielded the electron movement. It is believed that this study will provide new insight on the sustainable usage of water treatment-adsorbents.
