VALORISATION OF SUNFLOWER (TITHONIA DIVERSIFOLIA) STALKS FOR THE ADSORPTION OF PB(II) AND FE(II) FROM AQUEOUS MEDIA
Sunflower (Tithonia diversifolia) stalk was harnessed as a precursor in preparing adsorbents for the removal of Pb(II) and Fe(II) from aqueous solutions. The biomass was acid activated by wet impregnation with phosphoric acid and carbonised at 500oC. The adsorbent was characterised using Fourier Transform Infra-Red Spectroscopy (FTIR), Branueur Emmet and Teller analysis (BET) and Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS). The surface area of the adsorbent obtained was 325.375 m2/g. The effect of metal ions concentration, adsorbent dosage and contact time was studied for both Pb(II) and Fe(II) uptake. The best fit isotherm model for Pb(II) and Fe(II) was Langmuir and Freundlich Models respectively. The monolayer adsorption capacity of the adsorbent to Pb(II) and Fe(II) was 31.55 mg/g and 35.84 mg/g respectively. The pseudo second order was the best fit kinetic model. The study was able to reveal that Sunflower (Tithonia diversifolia) stalk can be used to prepare low cost adsorbents for water treatment.