Water pollution is one of the major ecological threats people face around the world. Water contamination by organic and inorganic compounds is hazardous to both the environment and human health. Adsorption techniques have gained much attention in the field of water remediation due to their efficiency, simplicity in operation, and ease of implementation. However, the adsorbents currently being used are costly. The main objective of this work is to develop novel, low-cost adsorbents from waste material by modifying the adsorbent surface for water remediation. Adsorbent modifications involve various chemical and physical methods such as acid/base treatments, metal/metal oxide impregnation, functional group alteration, and steam/air activation. In chapter I, these modification methods are summarized along with characterization techniques and adsorption interactions available for contaminant removal. In chapter II, a novel activated carbon is introduced from the fruit of Garcinia cambogia with acid activation, for the removal of Pb(II) and Cd(II) from water. Activated carbon was prepared by soaking dried Garcinia cambogia pieces in 85% phosphoric acid and carbonizing at 650 °C in a muffle furnace for 1 h. Chapter III describes the modification of waste tire rubber as an adsorbent for heavy metal ion removal. This modification was done by mixing ground tire rubber (GTR) with chitosan dissolved acetic acid (2%) solution followed by NaOH treatment. Chitosan modified-GTR successfully removed more Pb(II) and Cu(II) ions than GTR, suggesting added amine groups on the GTR surface through chitosan modification enhanced the heavy metal ion adsorption. In chapter IV, caffeine, ibuprofen, and acetylsalicylic acid removals by hybrid magnetic Fe3O4/Douglas fir biochar adsorbent are discussed. Adsorptions were compared with non-magnetic Douglas fir biochar. The surface chemistry and composition of modified adsorbents were examined by SEM, SEM-EDX, TEM, PZC, XRD, XPS, FTIR, TGA, elemental analysis, and surface area measurements.

Water pollution has become an environmental catastrophe due to the rapid urbanization. The treatment of dumping of waste chemicals in water bodies has contributed to the increase in pollution. In addition to the pollution caused by waste chemicals, faecal bacteria such as Escherichia, Staphylococcus, Pseudomonas etc., can cause serious health issues. Techniques such as filtration and chlorination provide clean water but are associated with disadvantages such as toxic by-products. Although clean water can be still obtained by these techniques, the development of resistance by microorganisms with such conventional treatments of antibiotics is inevitable and poses a new threat. Various researches have taken place in the past few decades to provide clean drinking water. Photocatalysis is considered to be a promising viable alternative for the existing methods to solve the menace of water pollution. It is an advanced oxidation process where the reactive oxygen species are generated by using nanomaterials that can cause degradation of chemicals and pathogens. Particularly, photocatalysis using semiconductors and their composites have been tested for their use in the destruction of contaminants. Several methods have been used in the synthesis of nanomaterials and the variations in their morphologies have resulted in different applications such as photocatalysis and electrocatalysis. Among all semiconductors, TiO2 has been widely used in this application owing to their non-toxicity and abundance in availability. However, TiO2 can be activated only in the presence of UV light. Therefore, the formation of heterojunctions, doping of metals/no- metals in TiO2 has enabled the activation of TiO2 in the visible region. The former approach has also been studied with ceria and silver salts combination. Besides conventional metal oxides, other transitional metal oxides such as copper oxide and bismuth oxide have also been studied owing to its conducting property and facile growth on substrates respectively for enhanced photocatalysis. All the above tweaking has enabled efficient charge separation, band gap reduction, and prevention of recombination. In this thesis, all the nanomaterials and their composites have been synthesized using simple methods such as solution combustion, hydrothermal, solution co-precipitation, and chemical deposition. The primary aim of this thesis is to synthesize various effective nanomaterials with different morphologies, bandgap engineered nanocomposites, metal or non-metal doped metal oxides for efficient waste water treatment of dyes, antibiotics, phenols, and bacteria. Besides, relying on photocatalytic ability, the photoconductivity and intrinsic conducting properties of nanomaterials were exploited to perform photoelectrocatalysis that enhances the rate of decontamination to several orders than photocatalysis. In addition to focusing on increasing the rate of degradation, the main drawback of photocatalysis which is catalyst retrieval has been overcome using conducting substrates and nanomaterial coated substrates for efficient photocatalytic and photoelectrocatalytic decontamination of waste water. All the structural, morphological, chemical and optical properties were thoroughly studied using various characterization techniques such as XRD, SEM, TEM, XPS, UV-DRS, PL respectively. The rate kinetics of dye, antibiotic and phenol degradation was examined. Experimental data was tested with the proposed model in the case of photoelectrocatalytic degradation. The photocatalysts were also studied for its reusability for many cycles. All the proposed works have analyzed the reason for the enhanced activity by performing scavenger reactions to determine the responsible reactive oxygen species. Thus, this thesis exhibits a thorough understanding of how to design and engineer nanomaterials for photocatalytic and photoelectrocatalytic water remediation. The following are the chapters discussed in this thesis. Chapter 1 discusses the drawbacks associated with the current waste water treatment methods and the possibilities of photocatalysis to replace the existing treatments. The advantages of certain transition metals, conventional methods of synthesis and various other properties of the nanomaterials have been discussed. Chapter 2 explains the synthesis of TiO2 nanobelts using combustion synthesized TiO2 under UV and solar irradiation. The catalyst has been characterized for its structural, morphological, chemical and optical properties. The degradation of anionic and cationic dyes and their activity against E.coli bacteria have been evaluated. The efficiency of this catalyst has been compared with commercial Degussa P25. This study shows the morphological influence of nanomaterials on photocatalytic activity. Chapter 3 describes the synthesis of Ag3PO4 impregnated combustion synthesized TiO2 nanobelts using co-precipitation technique. The activity of this material has been studied under solar light. The catalyst has been characterized for its structural, morphological, chemical and optical properties. Similar to the previous chapter, the degradation of dyes and the antibacterial activity of this catalyst has been compared with commercial Degussa P25. This study explains the importance of morphology and charge carrier facilitation in the case of heterojunction formation. Chapter 4 explains the synthesis of ceria nanoflakes by solution combustion method using ascorbic acid as fuel and PEG assisted sonochemical method. The catalyst has been characterized for its structural, morphological, chemical and optical properties. The effect of silver salts such as AgBr on ceria/Ag3PO4 under visible region for degradation of dyes and antibacterial activity has been evaluated. This work elucidates the effect of band engineering in the charge carrier dynamics between interfaces of components within the catalysts. Chapter 5 elucidates the synthesis of vanadium, nitrogen co doped TiO2 catalysts for the simultaneous degradation of microbes and antibiotics. The primary aim of this work is to understand whether interstitial or substituted doped nitrogen will be effective in the presence of vanadium. The photoactivity of this novel catalyst was studied for its synergistic degradation of antibiotics and bacteria simultaneously towards the prevention of microbial resistance towards antibiotics. Chloramphenicol and E.coli were subjected to photodegradation under visible light. Chapter 6 explains the synthesis of copper oxide based nanomaterial for antibiotic and bacterial degradation by photoelectrocatalysis. In order to enhance the rate of photodegradation, photocatalysis has been upgraded with the application of a potential to photocatalytic systems that possess better charge conducting capability. Highly network like copper oxide has been synthesized using conventional combustion synthesis method and compared with copper oxide nanorods synthesized by hydrothermal method. The rate kinetics of photocatalytic and photoelectrocatalytic degradation of antibiotics has been examined thoroughly and validated based on a cyclic network model. This work demonstrates the synergistic rate enhancing capacity upon combining photocatalysis and electrocatalysis. Chapter 7 discusses the fabrication of Cu/CuO/FTO (fluorine doped tin oxide) based substrates for bacterial degradation. Considering the difficulties in photocatalyst retrieval processes and realizing the importance of electrocatalysis, conducting substrates such as Cu strip, FTO were subjected to antibacterial treatment. Formation of copper oxide onto copper strip during the course of reaction forced us to develop CuO/Cu and CuO/FTO interfaces to examine the photocatalytic and photoelectrocatalytic killing of E.coli. Chapter 8 investigates the fabrication of Bi2O3/Ag based material for photocatalytic and photoelectrocatalytic degradation for phenols and substituted phenols. This work starts with fabrication of Bi2O3 working electrodes by chemical deposition. Photodegradation experiments were conducted under UV irradiation and enhancement of the rate of degradation was observed when the working electrode was deposited with silver nanoparticles via chemical reduction method. Formation of the intermediate Bi(OH)x on Bi2O3 or Bi2O3/Ag has resulted in better hydroxyl radical generation upon excitation. Similarly, surface plasmon resonance due to silver nanoparticles was found to be responsible for augmentation in degradation efficiency of phenol. Chapter 9 briefly summarizes the work and provides future directions. The research work thus attempts to design and engineer photocatalytic nanomaterials that are better than the existing materials and emphasizes the importance towards water remediation.

Water remediation utilizing sorption has found strong interest due to its inexpensiveness, universal nature and ease of operation. In particular, thermo-responsive sorbents consisting of N-isopropylacrylamide (NIPAAm) offer significant potential as “smart” and advanced materials to remove multiple aqueous pollutants. NIPAAm exhibits excellent thermo-responsiveness, which senses the external temperature variation and changes its swelling and sorption behaviors in a sharp and rapid manner. At the beginning of this work, an extensive review of literature has been compiled to provide a summary of NIPAAm-based thermo-responsive sorbents in water/wastewater remediation applications. Initially, we developed a novel approach to synthesize and characterize NIPAAm copolymeric hydrogels. Four different polyphenolic crosslinkers including curcumin multiacrylate (CMA), quercetin multiacrylate (QMA), 4,4’-dihydroxybiphenyl diacrylate (44BDA) and chrysin multiacrylate (ChryMA) were successfully incorporated into crosslinked hydrogels. Their temperature responsiveness and lower critical solution temperature (LCST) were characterized using swelling studies and differential scanning calorimetry (DSC). Increasing the crosslinker content resulted in a significant decrease in the swelling ratio and LCST, which was due to the increased crosslinking and hydrophobicity introduced by the polyphenolic crosslinkers. We also demonstrated the application of two sets of aforementioned crosslinked hydrogels (NIPAAm-co-CMA and NIPAAm-co-44BDA) as effective gel sorbents to capture phenol as a model contaminant. Temperature-dependent sorption was evaluated through a binding study of phenol at 10°C and 50°C. Significant enhancement in the sorption was observed at 50°C, and this can be attributed to the phase transition induced hydrophobic interactions between the copolymer gel and phenol. Moreover, the obtained hydrogels possessed facile and efficient regeneration ability in water at 10°C, without requiring harsh solvent treatment or high energy input. Building on the sorption behavior observed with crosslinked NIPAAm hydrogels, we extended the investigation to linear copolymer systems, and these were demonstrated as a temperature responsive flocculants. Here, NIPAAm copolymers consisting of 2-phenylphenol monoacrylate (2PPMA) were successfully developed as smart flocculants to remove metal oxide nanoparticles (e.g., Fe3O4, CeO2, TiO2). The incorporation of 2PPMA enhanced the flocculation at temperatures above the LCST (e.g., 50°C), which was due to the combined hydrophobicity of 2PPMA and NIPAAm. Overall, NIPAAm-based sorbents have a variety of applications in aqueous pollutant removal and are a promising class of materials for cost-effective water remediation technology.

The goal of the dissertation was to optimize synthetic parameters to tune the properties of two layered materials, MoS2 and MnO2 for applications such as antibacterial, energy storage and water remediation. Two aspects of the materials were investigated. Firstly, the synthetic parameters were tuned to prepare material with different morphologies and then the effect of morphology and structure on interaction with bacterial cells was studied. In the second part, the research was focused on tuning the synthetic parameters to improve the intrinsic conductivity of the material for electrocatalytic applications. This dissertation work primarily focuses on understanding the catalytic and antibacterial activity of layered MnO2 and MoS2. One research effort was focused on the antibacterial mode of action of layered nanosheets of MnO2 and MoS2 toward Gram-positive and Gram-negative bacteria. Bacillus subtilis and Escherichia coli bacteria were chosen as model organisms, which were treated individually with randomly oriented and vertically aligned nanosheets. Viability measurements of bacteria, by flow cytometry and fluorescence imaging, showed that vertically aligned MnO2 and MoS2 nanosheets revealed the highest antimicrobial activity and that Gram-positive bacteria showed a higher loss in membrane integrity, compared to Gram-negative bacteria. Moreover, scanning electron microscopy images suggested that the nanosheets compromised the cell wall upon interaction, which led to significant bacterial morphological changes. We propose that the peptidoglycan mesh in the bacterial wall is likely the primary target of the 2D layered nanomaterials. Another focus of the dissertation research investigated the effect of structural and geometrical changes of layered materials on the properties which affect the intrinsic conductivity of material. In the first study, the electrocatalytic activity of layer-by-layer (LbL) deposited 1T'-MoS2 (metallic phase) on a fluorine-doped tin oxide (FTO) substrate was investigated for the hydrogen evolution reaction (HER) as a function of layer number. Conversion of the deposited 1T'-MoS2 to the semiconducting 2H-MoS2 phase via exposure to 532 nm wavelength light, confirmed by Raman spectroscopy and scanning tunneling spectroscopy (STS), allowed a direct comparison of the HER activity of the two phases at a constant mass loading and surface area on the same substrate. The morphology, thickness and roughness of the deposited MoS2 layers as a function of the number of deposition cycles were investigated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The results showed that the average roughness of the surface increased with the number of deposition cycles, indicating that the thickness of the deposited layered material became heterogeneous with increasing cycle number. For a given number of deposition cycles (i.e., similar mass loading), 1T'-MoS2 exhibited a lower overpotential for the HER than the 2H-MoS2 phase. For example, at a sample thickness of 19.7 ± 2.8 nm (20 LbL cycle) the overpotentials for the HER for 1T'-MoS2 and 2H-MoS2 were 0.54 and 0.61 V, respectively (at a current density of -2 mA/cm2). Overall, the overpotential for HER associated with both MoS2 phases decreased as the mass loading increased. Our study revealed the heterogenous formation of few layer 1T'-MoS2 on the surface, providing a novel approach to improve HER activity towards water splitting applications. A further research effort studied birnessite, focusing on the activity of exfoliated birnessite and the role of birnessite defects for water oxidation. The catalytic activity of layered MnO2 has been studied widely. Birnessite has the lowest oxygen evolution reaction (OER) activity in alkaline media compared to other manganese oxide phases. A motivation for the study was to investigate the OER activity of exfoliated-restacked birnessite sheets which can lead to a better understanding of the birnessite catalytic performance. Synthesized birnessite was exfoliated into monolayer sheets via a cation exchange method. Characterization of the birnessite monolayer sheets using AFM and scanning tunneling microscopy (STM) revealed the presence of the holes and point defects. The phase and conductivity of monolayer sheets were measured by STS. Electrochemical characterizations of exfoliated birnessite have shown that nanosheets of birnessite expose a great number of active sites and exhibit facile electrode kinetics as a result of the defective sheets. In particular, the overpotential of exfoliated birnessite synthesized at 400°C was 450 mV compared to 550 mV for the exfoliated birnessite synthesized at 1000°C. The results indicate that the defective exfoliated sheets have higher conductivity and higher OER activity compared to defect free exfoliated sheets. Additional research of birnessite focused on its activity for the arsenite (i.e., As(III)) oxidation reaction. Birnessite polytypes were synthesized by decomposition of KMnO4 at different temperatures, and three polytypes including two-layer orthogonal (2O), two-layer hexagonal (2H) and three-layer rhombohedral (3R) were identified in the samples. The synthetic temperature controlled the phase formation and heterogeneity of the phases. Birnessite synthesized at 600°C contained 2H/3R phases which showed the highest activity with first order rate constant of the 0.741 h-1 which is 3.6 and 24 times higher than Birnessite synthesized at 800 and 1000°C, respectively. The structural change of the polytype birnessite after As(III) oxidation was studied by pair distribution function experiment. Results indicated that Mn4+ in the birnessite was reduced to Mn3+ and that this reduced species migrated from the in-layer position to the interlayer region. Furthermore, we report the results of in-situ AFM of birnessite sheets exposed to arsenite which provides a detailed understanding of the arsenite oxidation reaction at the birnessite surface. The reductive dissolution of birnessite was shown to be more active on the edges compared to the basal plane of birnessite. Our findings have important implications for material design aimed at removal of arsenite in purification processes. / Chemistry

Water polluted by pharmaceuticals, metals, and phosphates can be hazardous to both the environment and human health. The main aim of this study is to develop low cost, green adsorbents for removal of these pollutants from aqueous solution as a low cost alternative to activated carbon. Biochar was produced from the fast pyrolysis of Douglas fir. Magnetic biochar was prepared by magnetite (Fe3O4) precipitation onto the biochar’s surface from an aqueous Fe3+/Fe2+ solution upon NaOH treatment. Both Douglas fir and magnetic Douglas fir biochars have high uptake and adsorption capacity. Chapter I provides an overview of different biochar production techniques and modification methods. Chapter II is a study of the aqueous adsorption of pharmaceutical products, 4-nitroaniline (4NA), salicylic acid (SA), benzoic acid (BA) and phthalic acid (PA) using Douglas fir and magnetic Douglas fir biochar. The surface chemistry and composition of the magnetic biochar were examined by SEM, SEM-EDX, TEM, PZC, XPS, XRD, elemental analysis, and surface area measurements. Chapter III describes the removal of lead and cadmium using both magnetic and nonmagnetic Douglas fir biochar and Chapter IV describes the removal of phosphate from waste water. In Chapter V, this low cost adsorbent (magnetic Douglas fir biochar) was introduced into an undergraduate laboratory to expose students to water quality issues and methods of contaminant removal enhancing their understanding of these important environmental issues. This experiment introduces new and interesting approaches to water purification as well as deepens the student’s understanding of present environmental concerns regarding pharmaceutical contaminants in wastewater.

Water pollution represents one of the major concerns of the modern world, after scientific and industrial development that generates hazardous organic and inorganic contaminants. Biochar (BC) has gained tremendous attention in the past decade as a cheap and efficient adsorbent for organic and inorganic contaminants from aqueous solutions. BC is considered to be a low-cost alternative to activated carbon, however, BC typically suffer performance reductions due to their low surface areas and poor mechanical properties. The main objective of this work is to develop novel biochar materials by modifying the biochar surface for the removal of organic and inorganic contaminants from water. In recent years, biochar modifications involving various methods such as, acid/base treatment, impregnation of mineral sorbents, functional groups incorporation, steam activation and magnetic modification have been widely studied. Chapter I summarizes these biochar modification methods. In Chapter II, Chitosan-Modified fast pyrolysis BioChar (CMBC) was used to remove Pb2+ from water. CMBC was made by mixing pine wood biochar with a 2% aqueous acetic acid chitosan (85% deacylated chitin) solution followed by treatment with NaOH. CMBC removed more Pb2+ than non-modified biochar suggesting that modification with chitosan generates amine groups on the biochar surface which enhance Pb2+ adsorption. Chapter III describes the fast nitrate and fluoride adsorption and magnetic separation from water on iron oxide particles dispersed on Douglas Fir biochar. Nitrate and fluoride adsorption occurred by electrostatic attraction over the wide 2 to 10 pH range. In the chapter IV, aniline and nitrobenzene removal from water was studied using magnetized and nonmagnetized Douglas Fir biochar. The adsorption of aniline and nitrobenzene occurred mainly through pi-pi electron interactions over the wide 2 to 12 pH range and H-bonding. The surface morphology, chemistry, and composition of the modified biochars were examined by SEM, SEM-EDX, TEM, PZC, XPS, XRD, FTIR, TGA, DSC, elemental analysis, and surface area measurements.

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No description available.

Natural contamination of groundwater by arsenic (As) has become a critical public health threat in many parts of the world. The well-known regions associated with As contamination of groundwater are Bangladesh and West Bengal, India where approximately 100 million people are exposed to high levels of arsenic by drinking arsenic-contaminated groundwater and about 35 million are already affected. Long-term drinking of arsenic-contaminated water leads to arsenicosis, which is characterized by cancers of the skin, organ disease and certain other types of cancer. Affected developing communities are at higher risk because they may not have access to conventional water treatment facilities. This problem has focused research efforts on providing accessible arsenic removal technologies. In this study, cactus mucilage, an extract from the Opuntia ficus-indica (also known as Nopal and Prickly Pear cactus), is investigated as a natural agent for As removal from water. Cactus mucilage is a natural hydrocolloid with known flocculant abilities and a demonstrated interaction with As. Two mucilage fractions were extracted - a gelling extract (GE) and a non-gelling extract (NE). Two As removal systems were studied: the cactus mucilage acting alone and a hybrid mucilage and iron treatment system. The mechanism of action of the mucilage's interaction with arsenic was also studied. Batch experiments were used to study the arsenic removal systems. Total As was determined with Hydride Generation - Atomic Fluorescence Spectroscopy (HGAFS) and Inductively Coupled Plasma - Mass Spectroscopy (ICPMS). In the hybrid system, iron (Fe) was also determined by ICP-MS. Total Organic Carbon (TOC) analysis was used to determine mucilage concentration. Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Ultraviolet-Visible Spectroscopy (UVVIS) were used to study the molecular composition. Additionally, the mucilage was characterized by Transmission Electron Microscopy (TEM) for physical morphology and by Laser-induced Breakdown Spectroscopy (LIBS) and High Performance Liquid Chromatography (HPLC) for inorganics and sugars composition. Both cactus extracts showed an interaction with As by binding and transporting As to the air-water interface of the treatment container, with GE and NE causing a 14% and 9% respective increase in As concentration at the air-water interface. TOC analysis showed that the mucilage migrated to the top of the treatment container but also settled on the bottom. This interaction with As was shown to be pH dependent - optimal performance was at pH 5.5 and 9. The mucilage interaction with As was also dependent on the ionic strength of the solution. ATR-FTIR showed the role of the carboxyl functional group as the binding site for the As(V). The hybrid iron-mucilage treatment system was studied in order to capitalize on the strong affinity of iron for As, as well as to exploit the flocculant properties of the mucilage. Mucilage was successfully applied as a coagulant aid in the removal of As by Fe(III) salt, achieving between 75% to 96% As removal. The process depended on the hydrolysis of the Fe(III) salt to form iron hydroxides and oxyhydroxides, which reacted with and adsorbed the dissolved As(V). The iron arsenate colloidal precipitate which formed was then adsorbed onto the mucilage surface forming larger, heavier, denser flocs. The As removal increased with increasing mucilage concentration reaching a maximum at 100 mg/L GE. Increasing Fe(III) concentration increased the As removal reaching an optimum concentration at 40 mg/L Fe. The As removal had rapid kinetics, achieving visual separation within 10 minutes and completing the majority of the removal within 30 minutes. These results are important because they demonstrate that the mucilage is the versatile basis for an As removal treatment, being able to interact as a complexant for the arsenic as well as an effective coagulant aid for iron arsenate precipitation.

Utilizing biomass such as lignin, bamboo, soybean, corn stalk, rice husk, etc., as a carbon source to produce graphene-based nanomaterials has been reported recently. However, the potential of using such nanomaterials for engineering and environmental applications has not been realized. This dissertation investigates the use of graphene-based nanomaterials synthesized from using biomass as a carbon source for water remediation and cement-based composites’ (CBCs) property enhancement. The first chapter introduces graphene and graphene-based nanomaterials, as well as the synthesis and application of graphene-based nanomaterials for removing heavy metals in an aqueous solution and for property enhancement in CBCs. The experimental investigation on the pyrolytic synthesis of graphene-encapsulated iron nanoparticles from biochar (BC) as the carbon source (BC-G@Fe0) was covered in the second chapter. Two synthetic routes for producing BC-G@Fe0, i.e., impregnation-carbonization (route-I) and pyrolysis-impregnation-carbonization (route-II) processes, were investigated experimentally using different characterization techniques and heavy metal removal methods. The third chapter reports the experimental performances of the heavy metal removal of Pb2+, Cu2+, and Ag+ from an aqueous solution using BC-G@Fe0. The effectivenesses of various adsorption benchmarks, such as pH, kinetics, and isotherms were assessed. Additionally, the removal efficiency of BC-G@Fe0 was evaluated. BC-G@Fe0 sample made from route II, in particular, FeCl2-impregnated-BC with 15% wt% iron loading carbonized at 1000 ℃ for 1h showed promising Pb2+, Cu2+, and Ag+ removal capacities of 0.30, 1.58, and 1.91 mmol/g, respectively. The fourth chapter experimentally investigated the reinforcement effect of commercially sourced, industrial graphene nanoplates (IG) on the mechanical properties of CBCs. This investigation was based on a hypothesis that the uniform dispersion of IG would significantly enhance the compressive strength of CBC. The main outcome of this research was that, while the wet dispersion mixing process of IG into CBC did not consistently yield significant increases in the composite compressive strength, but the newly proposed dry dispersion process demonstrated significant increases (22%) in the composite compressive strength. Chapter Five investigated the synthesis of lignin-based graphene nanoplatelets (LG) and their application in CBC reinforcement. The main findings were that LG did not show impressive increases compared to IG, even when dry dispersion was introduced. This was attributed to LG's lack of effective surface area compared to IG. Finally, a general conclusion and outlook for the future of research into biomass-based graphene nanomaterials were discussed in chapter six.