Browsing by Author "Soludongwe, Siviwe Mlamli"

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    Co-production of furfural and wood composite products from bio-based processing residues
    (Stellenbosch : Stellenbosch University, 2020-03) Soludongwe, Siviwe Mlamli; Tyhoda, Luvuyo; Chimphango, Annie F. A.; Stellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science.
    ENGLISH ABSTRACT: There is an increased environmental concern to move from a petroleum-based economy to a more bio-based economy. Lignocellulosic materials have been shown to be a good source of building blocks for value-added products such as furfural. The integration of lignocellulosic material in a biorefinery concept proves to be necessary and beneficial in the industry and global context. The lignocellulosic material was sourced locally and included sugarcane (Saccharum officinarum) bagasse, Blue gum (Eucalyptus globulus) and Long-leaved wattle (Acacia longifolia). The lignocellulosic materials were pre-treated with NaOH aimed at enhancing the flexural and physical properties of the manufactured panels as well as extracting hemicelluloses. The effect of the treatment on fibres and resultant by-products were evaluated using wet chemical and instrumental methods, such as high-performance liquid chromatography (HPLC), molecular weight, size-exclusion chromatography (SEM) and Fourier-transform infrared spectroscopy (FTIR). In the present study, the co-production of composite panels and furfural was investigated. The aim was to integrate the biorefinery concept in using biomass waste and alkali pre-treatment to produce furfural. The composite panels were manufactured using untreated and alkaline treated lignocellulosic material, while furfural was produced from the pre-treated by-products. Moreover, this study set out to simultaneously add value to the by-products from pretreated lignocellulosic material by producing furfural, which had not been done previously. In order to produce the furfural, a central composite statistical design (CCD) was used with independent variable temperatures (150-170 °C), time (30-90 min) and the response variable furfural yield, while acidic concentration (2wt%) and solid loading (14wt%) were kept constant. The experimental conditions were sourced with reference to literature to mimic the industrial standards. The interaction of the independent variables and their effect on the produced furfural were evaluated using the Pareto analysis of variance. Response surface models were used to develop and predict the parameters yielding optimum furfural yield. The yields of furfural from the acid hydrolysis of the extracted hemicelluloses was 39, 45 and 44 mol% for sugarcane bagasse, E.globulus and A.longifolia, respectively. These values were slightly lower than the predicted values from the CCD. The low furfural yields led to a Pareto chart showing no confidence of independent variables on the furfural yield. Furthermore, the performance of the treated materials compared to untreated materials were evaluated on the properties of the manufactured composite panels, such as modulus of elasticity (MOE), modulus of rupture (MOR), water absorption and thickness. Based on the results, the treated lignocellulosic materials enhanced the properties of the composite panels as compared to the untreated lignocellulosic materials. In the treated panels the modulus of rupture was 10.42 MPa, 11.13 MPa and 6.4 MPa for sugarcane bagasse, E. globulus and A. longifolia, respectively. The manufactured panels met the minimum requirements and are classified as low density to medium density boards according to ANSI A208.1. These panels prove useful in the wood panel industry as core material for solid doors.