Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Chemical and Biochemical Engineering

Supervisor

Paul A Charpentier

Abstract

The main objective of the present research was to develop environmentally friendly and cost-effective porous carbon materials of improved properties from waste hemp fibers. Two different types/categories of porous carbons were prepared from hemp fibers. In one type, porous carbon materials were developed by a simple one-step method of carbonization and activation. The other type of carbon materials developed in this study were nitrogen-containing activated carbons, which were developed by introduction of nitrogen-containing functional groups on the surface of hemp fibers followed by activation and carbonization. The pore structure/distribution and surface chemistry of the prepared carbons were investigated through the analysis of BET (Brunauer-Emmett-Teller) surface area, pore size and pore volume, X-ray diffraction (XRD), scanning electron microscopy (SEM) images, high resolution transmission electron microscopy (HRTEM) images, Fourier transform-infrared (FT-IR) spectra, and Raman scattering. The carbons developed in this study were mostly mesoporous, and the BET surface area and pore volume of the carbon prepared under optimal conditions were significantly higher than those of commercially available carbon products such as granular and powder activated carbons. The potential of hemp fiber-derived carbons as adsorbents for removal of model naphthenic acids from contaminated aqueous solutions was studied, and the removal efficacy of the prepared carbons was evaluated against that of commercial granular activated carbon. The carbons prepared in this study demonstrated substantially higher efficiency than the commercial carbons for removal of model naphthenic acids from aqueous streams.

Summary for Lay Audience

The holistic approach for combating with pressing global issues related to energy, environment, and materials/resources requires joint efforts from academia/research, industry, and government sectors. In recent years, the concepts of reducing the dependency on non-renewable fossil-based resources, and utilization of renewable resources for energy generation, environmental remediation, and product/material development are being increasingly sought to address such pressing issues. This research work is a small effort in the direction of utilization of renewable resources for development of a material that is being sourced from fossil-based resources, and utilization of such material(s) in environmental remediation.

The research work presented in this thesis builds on the “biomass thermochemical treatment technology” developed in the research lab led by Prof. Paul Charpentier, and utilizes bast hemp fiber as a renewable resource for making porous activated carbon. The porous activated carbons, generally obtained from fossil/coal-based resources, have widespread application in several areas including materials, engineering, and environmental remediation. In this research, porous activated carbon materials were developed from hemp fiber biomass in two ways – i) by simple one step method of carbonization and activation of biomass, and ii) by introduction of nitrogen-containing functional groups on surface of hemp fibers followed by carbonization and activation. Characteristics of the prepared activated carbons were studied by well-known characterization methods that includes i) analysis of BET (Brunauer-Emmett-Teller) surface area, pore size and pore volume, ii) study of scanning electron microscopy (SEM) images and high resolution transmission electron microscopy (HRTEM) images, iii) study of Fourier transform-infrared (FT-IR) spectra, and iv) evaluation of X-ray diffraction (XRD) and Raman scattering patterns. The carbons developed in this study were mostly mesoporous, and the BET surface area and pore volume of the carbon prepared under optimal conditions were significantly higher than that of the commercially available carbon products such as granular and powder activated carbons. The carbons obtained from hemp fibers not only had improved characteristics over commercial products, but also demonstrated substantial potential on their applicability for environmental remediation wherein the hem fiber-based carbons were significantly better over the commercial carbons for removal of model naphthenic acids from aqueous streams.

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