Lignin from Brewers’ Spent Grain: Structural and Thermal Evaluations
Lignocellulose is a renewable ubiquitous material that comprises cellulose, hemicellulose, and lignin. Lignin has been isolated from different lignocellulosic biomass via chemical treatments, but there has been little or no investigation carried out on the processing of lignin from brewers’ spent gr...
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MDPI AG
2023-05-01
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| Series: | Polymers |
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| author | Oluwashina Philips Gbenebor Oludolapo Akanni Olanrewaju Mohammed Awwalu Usman Samson Oluropo Adeosun |
| author_facet | Oluwashina Philips Gbenebor Oludolapo Akanni Olanrewaju Mohammed Awwalu Usman Samson Oluropo Adeosun |
| author_sort | Oluwashina Philips Gbenebor |
| collection | DOAJ |
| description | Lignocellulose is a renewable ubiquitous material that comprises cellulose, hemicellulose, and lignin. Lignin has been isolated from different lignocellulosic biomass via chemical treatments, but there has been little or no investigation carried out on the processing of lignin from brewers’ spent grain (BSG) to the best of authors’ knowledge. This material makes up 85% of the brewery industry’s byproducts. Its high moisture content hastens its deterioration, which has posed a huge challenge to its preservation and transportation; this eventually causes environmental pollution. One of the methods of solving this environmental menace is the extraction of lignin as a precursor for carbon fiber production from this waste. This study considers the viability of sourcing lignin from BSG with the use of acid solutions at 100 °C. Structural and thermal analyses were carried out on extracted samples, and the results were compared with other biomass-soured lignin to assess the proficiency of this isolation technique. Wet BSG sourced from Nigeria Breweries (NB), Lagos, was washed and sun-dried for 7 days. Tetraoxosulphate (VI) (H<sub>2</sub>SO<sub>4</sub>), hydrochloric (HCl), and acetic acid, each of 10 M, were individually reacted with dried BSG at 100 °C for 3 h and designated as H2, HC, and AC lignin. The residue (lignin) was washed and dried for analysis. Wavenumber shift values from Fourier transform infrared spectroscopy (FTIR) show that intra- and intermolecular OH interactions in H2 lignin are the strongest and possess the highest magnitude of hydrogen-bond enthalpy (5.73 kCal/mol). The thermogravimetric analysis (TGA) results show that a higher lignin yield can be achieved when it is isolated from BSG, as 82.9, 79.3, and 70.2% were realized for H2, HC, and AC lignin. The highest size of ordered domains (0.0299 nm) displayed by H2 lignin from X-ray diffraction (XRD) informs that it has the greatest potential of forming nanofibers via electrospinning. The enthalpy of reaction values of 133.3, 126.6, and 114.1 J/g recorded for H2, HC, and AC lignin, respectively, from differential scanning calorimetry (DSC) results affirm that H2 lignin is the most thermally stable with the highest glass transition temperature (T<sub>g</sub> = 107 °C). |
| first_indexed | 2024-03-11T03:22:25Z |
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| spelling | doaj.art-68afa496c5a14434b8be5feb6da76a902023-11-18T02:58:45ZengMDPI AGPolymers2073-43602023-05-011510234610.3390/polym15102346Lignin from Brewers’ Spent Grain: Structural and Thermal EvaluationsOluwashina Philips Gbenebor0Oludolapo Akanni Olanrewaju1Mohammed Awwalu Usman2Samson Oluropo Adeosun3Department of Metallurgical and Materials Engineering, University of Lagos, Lagos 101017, NigeriaDepartment of Industrial Engineering, Durban University of Technology, Durban 4000, South AfricaDepartment of Chemical and Petroleum Engineering, University of Lagos, Lagos 101017, NigeriaDepartment of Metallurgical and Materials Engineering, University of Lagos, Lagos 101017, NigeriaLignocellulose is a renewable ubiquitous material that comprises cellulose, hemicellulose, and lignin. Lignin has been isolated from different lignocellulosic biomass via chemical treatments, but there has been little or no investigation carried out on the processing of lignin from brewers’ spent grain (BSG) to the best of authors’ knowledge. This material makes up 85% of the brewery industry’s byproducts. Its high moisture content hastens its deterioration, which has posed a huge challenge to its preservation and transportation; this eventually causes environmental pollution. One of the methods of solving this environmental menace is the extraction of lignin as a precursor for carbon fiber production from this waste. This study considers the viability of sourcing lignin from BSG with the use of acid solutions at 100 °C. Structural and thermal analyses were carried out on extracted samples, and the results were compared with other biomass-soured lignin to assess the proficiency of this isolation technique. Wet BSG sourced from Nigeria Breweries (NB), Lagos, was washed and sun-dried for 7 days. Tetraoxosulphate (VI) (H<sub>2</sub>SO<sub>4</sub>), hydrochloric (HCl), and acetic acid, each of 10 M, were individually reacted with dried BSG at 100 °C for 3 h and designated as H2, HC, and AC lignin. The residue (lignin) was washed and dried for analysis. Wavenumber shift values from Fourier transform infrared spectroscopy (FTIR) show that intra- and intermolecular OH interactions in H2 lignin are the strongest and possess the highest magnitude of hydrogen-bond enthalpy (5.73 kCal/mol). The thermogravimetric analysis (TGA) results show that a higher lignin yield can be achieved when it is isolated from BSG, as 82.9, 79.3, and 70.2% were realized for H2, HC, and AC lignin. The highest size of ordered domains (0.0299 nm) displayed by H2 lignin from X-ray diffraction (XRD) informs that it has the greatest potential of forming nanofibers via electrospinning. The enthalpy of reaction values of 133.3, 126.6, and 114.1 J/g recorded for H2, HC, and AC lignin, respectively, from differential scanning calorimetry (DSC) results affirm that H2 lignin is the most thermally stable with the highest glass transition temperature (T<sub>g</sub> = 107 °C).https://www.mdpi.com/2073-4360/15/10/2346cellulosehemicelluloseligninlignocellulosespent grain |
| spellingShingle | Oluwashina Philips Gbenebor Oludolapo Akanni Olanrewaju Mohammed Awwalu Usman Samson Oluropo Adeosun Lignin from Brewers’ Spent Grain: Structural and Thermal Evaluations Polymers cellulose hemicellulose lignin lignocellulose spent grain |
| title | Lignin from Brewers’ Spent Grain: Structural and Thermal Evaluations |
| title_full | Lignin from Brewers’ Spent Grain: Structural and Thermal Evaluations |
| title_fullStr | Lignin from Brewers’ Spent Grain: Structural and Thermal Evaluations |
| title_full_unstemmed | Lignin from Brewers’ Spent Grain: Structural and Thermal Evaluations |
| title_short | Lignin from Brewers’ Spent Grain: Structural and Thermal Evaluations |
| title_sort | lignin from brewers spent grain structural and thermal evaluations |
| topic | cellulose hemicellulose lignin lignocellulose spent grain |
| url | https://www.mdpi.com/2073-4360/15/10/2346 |
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