Evaluation of the sawdust modified with diethylenetriamine as an effective adsorbent for Fe (III) removal from water.

Heavy metals are environmental pollutants that nowadays a lot of efforts are made to remove them. In this research, the sawdust modified with diethylenetriamine as an effective adsorbent for Fe (III) removal from water samples was conducted. First, the sawdust was modified by diethylenetriamine. SEM analysis showed that the particle surface is changed by modification. Then the effective factors in Fe (III) removal such as pH, adsorbent dose, shaker speed and contact time were studied and optimized. The optimum conditions were employed for various Fe (III) concentrations (20–300 mg L-1) and in all cases, the removal rate was significant. The adsorbent has high capacity for Fe (III) removal in a way that it removed more than 95.0±0.3 % of Fe (III) (50 mg/L) by 1.5 g/L of adsorbent in 15 minutes. The Langmuir and Freundlich isotherms were applied to the adsorption process and their constants were evaluated. The adsorption equilibrium data fitted well to Langmuir isotherm. The maximum Langmuir adsorption capacity of Fe (III) ions was 200.0 mg/g. According to kinetics experiments of Fe (III), the adsorption process had more conformity to pseudo-second-order kinetic model. This method was successfully applied for Fe (III) removal from potable water, well water, river water and industrial wastewater samples.