Polyaniline as a Potential Adsorbent for the removal of Heavy Metals in Aqueous Solution

Polyaniline (PANI) has been one of the popular heavy metals adsorbent. It is commonly being used as coatings to other adsorbing materials. Lack of studies have been done on the capabilities of PANI as the single adsorbent, especially in nano range. Hence, this study was conducted to examine the potential of PANI as adsorbent in nano range and its adsorbing performance in different metal systems, which are lead and iron when being tested at different parameters, namely the initial concentration of metal ions, the adsorbent dosage and the contact time. The metal ions solutions were tested using Atomic Absorption Spectrometry (AAS). The data obtained were studied and being fitted to Langmuir and Freundlich adsorption isotherms to assess which type of isotherm did this adsorption mostly followed. The nano range PANI was found to be able to adsorb some amount of heavy metal ions when being tested and from this study, the optimum conditions for the removal of both metal ions were identified. The optimum initial concentration for both Pb²⁺and Fe²⁺were 40 ppm. The optimum adsorbent dosage for both Pb²⁺ and Fe²⁺ were found to be at 0.25g and the optimum contact time for Pb²⁺ was at 30 minutes while for Fe²⁺, the optimum contact time was found at 90 minutes. For the adsorption isotherm studies, the adsorptions were most probably followed the Langmuir adsorption isotherm. In comparison between both the metal ions, lead ions showed more favourable adsorption than iron ions based on the separation factor (RL) values. Further studies on the efficiency of PANI as adsorbent of heavy metals are highly recommended at different parameters and samples to produce the highest quality PANI and thus being able to remove high amount of heavy metals from contaminated wastewater.