Synthesis of Novel Surface-Modified Hematite Nanoparticles for Lead Ions Removal from Aqueous Solution

Abstract

In this research, hematite (α-Fe2O3) nanoparticles with novel surface- modified were synthesized using iron (III) chloride hexahydrate (FeCl3.6H2O) and oleic acid (C₁₈H₃₄O₂) as raw materials by hydrothermal method at 250°C. The structural analysis such as XRD, FT-IR, SEM, TEM and BET showed the distribution of the synthesized nanoadsorbent, so that more (>90%) nanorod structures (diameter of 30-60 and length of 400-700 nm) were among the less nanoscaly crystals with 40-100 nm as thickness. The high specific surface area of the novel synthesized hematite nanoparticles (31.29 m2/g) determined their high capability for the removal of lead ions (Pb2+) from aqueous solutions. The adsorption of lead ions onto the synthesized nano α-Fe2O3 was investigated by pH, adsorbent weight, lead ions concentration, and contact time in batch experiments and initial condition of 25±1°C, 120 rpm, so that the optimum conditions for lead ions adsorption was obtained. On this basis, the removal of lead ions increased with an increase in pH; the optimum solution value was about 6.5 due to the bothersome hydroxide constructions in higher pH values. The analysis of equilibrium data showed that the Langmuir isotherm model is suitable for describing the lead ions adsorption by nano α-Fe2O3. Furthermore, the maximum sorption capacity of Pb2+ was estimated to be 111 mg/g. The kinetic of lead ions adsorption onto the synthesized nano α-Fe2O3 was best fitted by the pseudo-second order model known as Ho model. As adsorption optimum condition, the maximum upatake capacity of 49.31 mg/g was recorded along with the efficiency of 98.62% for the remove of Pb2+ ions from aquoes solution (1 mg/g), using 20 mg/L nano α-Fe2O3 adsorbent at 4 hour contact time. From these results, it can be concluded that the synthesized α-Fe2O3 surface-modified nanoparticles is a promising and effective adsorbent to remove lead ions as a heavy metal pollutant from aqueous solutions.

Keywords

• Adsorption
• Hydrothermal
• Nanoparticle
• Hematite
• Kinetics
• Lead