Ph.D. STUDENT, UNIVERSITY OF JOHANNESBURG
HYDROGENATION OF BIOMASS-DERIVED MOLECULES FOR BIO-FUEL APPLICATIONS AND PLATFORM CHEMICALS
The transformation of biomass derived molecules into versatile platform chemicals and potential biofuel candidates has become an area of special interest in both industry and academia. This is in line with the global efforts to curtail the pressure on the traditional non-renewable and environmentally unfriendly fossil resources which are the main sources of these chemicals and energy fuels. The sustainability as well as eco-friendliness of biomass makes it a suitable candidate for producing fuels and chemicals. The major sources of feedstocks in biorefineries are the carbohydrates and lignocellulosic feedstocks. Biomass obtained from lignocellulosic feedstock would be considered most appropriate as it has no negative impact on food security. This is because lignocellulosic feedstock is non-edible. However, utilization of carbohydrate-based feedstock obtained from agricultural residue (e.g. corn stover, rice hulls) and municipal wastes are of great importance since they minimize the cost of waste disposal. My research focuses on transformation of biomass derived molecules into bio-fuel and other useful chemicals using cost effective approach such as solvent-free and very efficient catalysts. I have previously published a work in this area (DOI: 10.1021/acssuschemeng.6b01281). Currently I am working on improvement of the catalyst system I used previously for it efficiency and selectivity and I would like to communicate to the science community my new findings.
Abstract: Lipid recovery and purification from microalgal cells continues to be a significant bottleneck in biodiesel production due to high costs involved and a high energy demand. Therefore, there is a considerable necessity to develop an extraction method which meets the essential requirements of being safe, cost-effective, robust, efficient, selective, environmentally friendly, feasible for large-scale production and free of product contamination. The use of wet concentrated algal biomass as a feedstock for oil extraction is especially desirable as it would avoid the requirement for further concentration and/or drying. This would save considerable costs and circumvent at least two lengthy processes during algae-based oil production. This article provides an overview on recent progress that has been made on the extraction of lipids from wet algal biomass. The biggest contributing factors appear to be the composition of algal cell walls, pre-treatments of biomass and the use of solvents (e.g. a solvent mixture or solvent-free lipid extraction). We compare recently developed wet extraction processes for oleaginous microalgae and make recommendations towards future research to improve lipid extraction from wet algal biomass.
Pub.: 20 May '16, Pinned: 25 Aug '17
Abstract: A facile, efficient and environmentally-friendly protocol for the synthesis of xanthenes by graphene oxide based nanocomposite (GO-CuFe2O4) has been developed by one-pot condensation route. The nanocomposite was designed by decorating copper ferrite nanoparticles on graphene oxide (GO) surface via a solution combustion route without the use of template. The as-synthesized GO-CuFe2O4 composite was comprehensively characterized by XRD, FTIR, Raman, SEM, EDX, HRTEM with EDS mapping, XPS, N2 adsorption-desorption and ICP-OES techniques. This nanocomposite was then used in an operationally simple, cost effective, efficient and environmentally benign synthesis of 14H-dibenzo xanthene under solvent free condition. The present approach offers several advantages such as short reaction times, high yields, easy purification, a cleaner reaction, ease of recovery and reusability of the catalyst by a magnetic field. Based upon various controlled reaction results, a possible mechanism for xanthene synthesis over GO-CuFe2O4 catalyst was proposed. The superior catalytic activity of the GO-CuFe2O4 nanocomposite can be attributed to the synergistic interaction between GO and CuFe2O4 nanoparticles, high surface area and presence of small sized CuFe2O4 NPs. This versatile GO-CuFe2O4 nanocomposite synthesized via combustion method holds great promise for applications in wide range of industrially important catalytic reactions.
Pub.: 25 Feb '17, Pinned: 25 Aug '17
Abstract: The environmentally friendly esterification of acetosolv lignin (AL), obtained from pressed oil palm mesocarp fibers, is described, for the improvement of thermo-oxidative properties of poly(methyl methacrylate) (PMMA) films. Acetylation of AL was performed in ecofriendly conditions using acetic anhydride in the absence of catalysts. Acetylated acetosolv lignin (AAL) was successfully obtained in only 12 min with a solvent-free and catalyst-free microwave-assisted procedure. Lignins were characterized by Fourier transform infrared spectroscopy, size exclusion chromatography, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), confirming the efficacy of the methodology employed. AL and AAL as fillers in different concentrations (1% and 5%) were added to PMMA films. The thermal and mechanical properties of the lignin-incorporated films were analyzed by TGA, DSC, and dynamic mechanical analysis (DMA). The films incorporated with lignin and acetylated lignin presented initial degradation temperature (Tonset) and onset oxidative temperature (OOT) values higher than pure PMMA films, contributing thus to an enhancement of thermo-oxidative stability of PMMA. The DMA analyses showed that incorporation of AL or AAL increased the storage modulus (E′) of PMMA films, but did not affect their glass-transition temperatures (Tg). The results indicate the potential use of oil palm mesocarp lignin to enhance the thermo-oxidative properties of PMMA without compromising its mechanical response. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45498.
Pub.: 23 Jul '17, Pinned: 25 Aug '17