Nanotoxicity of Nanocatalysts in Biomass-Based Biofuel Production: Environmental and Health Implications
Kimone Naidoo
Durban University of Technology, South Africa.
Raveen Rathilall *
Durban University of Technology, South Africa.
*Author to whom correspondence should be addressed.
Abstract
The increasing demand for alternative fuel sources is largely influenced by the environmental impact of fossil fuels and their contribution to global warming. As a result, biofuels derived from biomass have gained attention as a potential alternative, aligning with Sustainable Development Goal 7, which highlights the need for affordable and clean energy. Despite the promising role of NCs in enhancing biodiesel production, limited research has systematically examined their potential toxic effects on human health and the environment. This study evaluates the toxicity effects of nano-catalysts (NC) used in biofuel production by identifying the types of biomass, exploring the NC used in the biofuel sector and analysing their effects on the environment and human health. A systematic literature review (SLR) was conducted using the PRISMA methodology. Relevant studies published between 2020 and 2024 were retrieved from Web of Science, PubMed, Science Direct, and the Multidisciplinary Digital Publishing Institute (MDPI), using a Boolean keyword search strategy. The EndNote software was used for screening and organising the studies, resulting in 42 articles meeting the inclusion criteria. Six key themes emerged through thematic analysis, namely, generations of biofuels, roles of nanotechnology in biofuel production, NC exposure concerns, health impacts, environmental effects, and nanotechnology safety measures. The study found that biofuels are gaining recognition as a cleaner alternative to fossil fuels. It highlighted that first-generation biofuels, which rely on edible feedstocks, raise concerns about food security, whereas second-generation biofuels use lignocellulosic biomass, reducing competition with food crops. The study also noted the growing use of NC to enhance biofuel production efficiency. Several categories of NCs are used in biodiesel production, such as metal oxide nanoparticles (e.g., Calcium Oxide - CaO, Magnesium Oxide - MgO, Iron Oxide - Fe₃O₄, Calcium/ Aluminium/ Iron Oxide - Ca/Al/Fe3O4, Potassium fluoride /Aluminium Oxide - KF/Al2O3, Tin Oxide - SnO₂), hydrotalcites, nano-zeolites, and magnetic nanoparticles. However, as their application expands, there are increasing concerns about occupational and environmental risks, particularly from inhalation during manufacturing and handling processes. Although certain regulatory frameworks and guidelines for nanomaterial use exist, the review highlights the need for more comprehensive safety protocols. The study recommended the utilisation of eco-friendly feedstocks, the development of green nano-catalysts, and the adoption of low-cost, recyclable catalysts to minimise environmental and health risks associated with nanomaterials in biofuel production. It is essential that industries handling nanomaterials adopt stringent nanosafety protocols, including the use of appropriate personal protective equipment (PPE), proper waste disposal, and adherence to WHO guidelines on nanomaterial handling and risk mitigation. The study advocates for further research into green NC derived from renewable resources to reduce nanotoxicity risks.
Keywords: Nano-catalyst, nanotoxicity, biomass, biofuel, occupational safety, environmental health