Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Mlsna, Todd E.

Committee Member

Wipf, David O.

Committee Member

Mlsna, Debra Ann

Committee Member

Street, Jason T.

Committee Member

Emerson, Joseph P.

Date of Degree

12-8-2017

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

Water polluted by metals and phosphates can be hazardous to both the environment and human health. The aim of this study was used to improve understanding of the adsorption properties of low-cost, green adsorbents for removal of pollutants from aqueous solution. Biochar was used as an adsorbent, which was produced from the gasification of pine wood waste and the fast pyrolysis of Douglas fir. Biochar is a bio-renewable product that can easily be modified, and the cost is lower compared to other adsorbents like activated carbon. The gasifier produced biochar was modified by coating the biochar surface with chitosan. Douglas fir biochar, produced by pyrolysis, was used in Mg/Al-layered double hydroxides (LDHs) and magnetization modifications. The Mg/Al-LDHs were prepared by co-precipitation using solutions of Mg and Al salts and NaOH treatment. The magnetization modification of the biochar was prepared by magnetite (Fe3O4) precipitation onto the biochar’s surface from Fe2+/Fe3+ solution upon NaOH treatment. Chapter I provides an introduction into biochar production, uses, and modification methods. Chapter II is a study of the aqueous adsorption Cu2+ and Cd2+ metals using chitosan coated and uncoated gasifier biochars. Chapter III focused on the removal of phosphate from aqueous solutions. Different ratios of Mg:Al in the LDHs were used to test the ratio’s affect on the adsorption properties of the modified adsorbents. Chapter IV describes the removal of phosphate from water using LDH modified biochars that are magnetized. This study looks at how the order in which the modifications were done influences the biochars adsorption ability. The surface chemistry and composition of each biochar in chapters II-IV were examined by SEM, SEM-EDX, TEM, PZC, XRD, elemental analysis, and surface area measurements. Each biochar’s adsorption ability was studied by pH effects, kinetics, and maximum capacity for the analyte.

URI

https://hdl.handle.net/11668/19580

Download

Share

COinS