This paper deals with the development of cellulose nanofibres (CNFs) reinforced biopolymers for use in packaging applications. Cellulose nanofibres were extracted from sawdust by a combination of chemical and mechanical treatments. The extracted cellulose nanofibres were chemically modified (fCNFs) and characterised by Fourier Transform Infrared Spectroscopy (FTIR). Bionanocomposites were prepared from biopolymers polylactic acid/polybutylene succinate (PLA/PBS) and cellulose nanofibres by compounding in a twin-screw extruder followed by injection moulding. The developed bionanocomposites were subjected to mechanical and thermal characterisation. As part of product development, CNF-biopolymer pellets were also extruded into filaments which were then 3D printed into prototypes. This work is a successful demonstration of conversion of waste residues into value-added products, which is aligned to the principles of circular economy and sustainable development.

The present study indicates that solid acid catalysis of crude tall oil (CTO) over a WO₃/ZrO₂ catalyst is effective in converting the CTO fatty acids components into biodiesel in high yield. Preparation of the catalyst by an impregnation method was selected and WO₃ activity was best at a loading mass fraction of 5% to ZrO₂ support and activation at 500°C for five hours under air at atmospheric pressure. Optimal reaction conditions were reaction temperature at 250°C; methanol to CTO molar ratio at 10; reaction time four hours, catalyst mass fraction of 3%; and stirring intensity at 625 rpm. The conversion at optimal reaction conditions was 70%. The catalyst was highly active at temperatures higher than 200°C. The biodiesel produced met some, but not all, the diesel quality parameters stipulated by standard specifications such as ASTM D6751 and EN14214.

Amongst the biofuels described in the literature, biohydrogen has gained heightened attention over the past decade due to its remarkable properties. Biohydrogen is a renewable form of H₂ that can be produced under ambient conditions and at a low cost from biomass residues. Innovative approaches are continuously being applied to overcome the low process yields and pave the way for its scalability. Since the process primarily depends on the biohydrogen-producing bacteria, there is a need to acquire in-depth knowledge about the ecology of the various assemblages participating in the process, establishing effective bioaugmentation methods. This work provides an overview of the biofilm-forming communities during H₂ production by mixed cultures and the synergistic associations established by certain species during H₂ production. The strategies that enhance the growth of biofilms within the H₂ reactors are also discussed. A short section is also included, explaining techniques used for examining and studying these biofilm structures. The work concludes with some suggestions that could lead to breakthroughs in this area of research.

This study investigated the comparative reinforcement effect of Achatina fulica snail shell nanoparticles, montmorillonite, and kaolinite nanoclay on greenpoxy. Greenpoxy nanocomposites of snail shell nanoparticles, montmorillonite, and kaolinite nanoclay were developed separately, with the nanofiller content ranging from 1 to 3% by weight. Specimens of the nanocomposites with different percentage weights of the nanoparticles were prepared using the resin casting method. Mechanical properties, such as the tensile strength, stiffness, hardness, and impact strength, and water absorption properties of the specimens were evaluated experimentally. It was observed that the incorporation of nanoparticles improved the mechanical properties of pure greenpoxy irrespective of the percentage weight, source, and type of reinforcement. Significantly, the loading of 1 wt.% of snail shell nanoparticles offered superior properties in most cases. Protein fibers and high-concentration calcium carbonate in snail shell nanoparticles, uniform dispersion, and excellent matrix/snail shell nanoparticle adhesion provided a strong structure, resulting in the high strength, stiffness, and decreased water uptake of the composites. The superior properties observed in snail shell nanoparticle composites suggest that this naturally sourced nanofiller can be used as a potential substitute for montmorillonite and kaolinite clays.

Ultrafiltration of lignin from black liquor was carried out in a stirred batch cell using polyethersulfone membranes. Parameters such as operating pressure, feed concentration, stirring rate and membrane cut-off size were varied and their effects on lignin retention and permeate flux were investigated. The operating pressure, feed concentration and stirring rate were varied in the ranges 150–350 kPa, 3–9% and 200–400 rpm, respectively. The membranes used had cut-off sizes of 5 kDa, 10 kDa and 20 kDa. A one-factor-at-a-time experimental design approach was applied in this study. Retention of lignin increased with increases in operating pressure, feed concentration and stirring rate, but decreased with an increase in molecular cut-off size of the membrane. Permeate flux on the other hand increased with increases in pressure, stirring rate and molecular cut-off size of the membrane but decreased with an increase in feed concentration. The extraction of lignin from black liquor was successfully carried out and extraction efficiencies as high as 86% could be achieved depending on the experimental conditions. The study was concluded with the recommendation of conducting additional experiments using a pilot plant in a continuous mode. Significance: The extraction of lignin from black liquor was successfully carried out and extraction efficiencies as high as 86% were obtained. The results can be used to extend the ultrafiltration of black liquor to an industrial scale.