<p> Biochar was produced from the fast pyrolysis of Douglas fir (DBC). Magnetic biochar (MDBC) was synthesized by mixing aqueous biochar suspensions with an aqueous Fe<sup>3+</sup>/Fe<sup>2+</sup> solution, followed by NaOH treatment, which causes precipitation of magnetite, Fe3O4 onto DBC. The DBC and the resulting MDBC were investigated as potential green adsorbents for lead remediation from the water. The surface chemistry of both chars was examined by SEM, SEM-EDX, TEM, PZC, and surface area measurements. Batch sorption studies were carried out at 25 °C, from pH 2-7 and with adsorbate concentration range of 50-200 mg/L. Maximum lead removal due to adsorption occurred at pH 5 for both DBC and MDBC. DBC was removed using filtration, whereas MDBC was removed magnetically. Remediated solutions were analyzed using atomic adsorption spectroscopy (AAS). Lead batch sorption studies were also conducted to study the effect of water hardness on rate and equilibrium data at different adsorbate concentrations to construct equilibrium isotherms. Three levels of water hardness were employed; low (30 mg/L), medium (90 mg/L) and high (150 mg/L). Sorption performances at 25 °C were evaluated using Langmuir and Freundlich adsorption isotherm models. The maximum Langmuir adsorption capacity at pH 5 and 25 °C for low, medium and high hard water were 106.54, 85.65 and 76.70 mg/g for DBC and 69.93 mg/g, 64.88 mg/g and 63.03 mg/g for MDBC. DBC and MDBC were also successfully applied for lead removal from natural water samples. Both chars can be used as potential low-cost green adsorbents for lead remediation.</p><p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:10606032 |
| Date | 12 October 2017 |
| Creators | Gogri, Dhara |
| Publisher | Mississippi State University |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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