Bioelectrochemical systems (BES) are commonly utilized to generate green electricity, chemicals, and materials through bioelectrocatalytic processes. Over the years, the growing interests in low carbon energy, wastes valorization and the sustainable bioremediation of environmental pollutants have generated interests in BES such as microbial fuel cells (MFC) and bioelectrochemical fuel cells (BFC). The MFCs are the most advanced BES that can ensure the microbial conversion of chemical energy into electrical energy. Therefore, this article seeks to review and present valuable literature on the fundamental operational principles, mechanisms and understanding of BES such as MFCs. It seeks to highlight the schematics of these systems along with the processes and mechanisms such as the oxidation of organic substrates ranging from acetate compounds to complex mixtures. Furthermore, the prospects, challenges, and future applications of BES technologies are presented. The findings indicate that BFCs and MFCs are hampered by low efficiencies, energy output, mass transfer, porosity, and proton conductivity of the electrode and membrane materials along with mechanical strength, scalability, biocompatibility, and chemical stability. However, BES could potentially impact on clean energy production, greenhouse gases mitigation, wastewater treatment, bioanalysis, biosensors, and environmental remediation in the future.

Abstract. The toxicity, persistence, and non-biodegradability of chemical pesticides have increased calls for the adoption of sustainable and cost-effective pest control measures. Biopesticides present a sustainable alternative to synthetic pesticides. However, the biopesticide utilization in agrarian countries like Nigeria remains low, resulting in increased chemical pesticide utilization. Therefore, this paper seeks to examine the current status, challenges, and prospects of biopesticides in Nigeria. The findings revealed that biopesticide utilization in Nigeria is low due to high costs, poor infrastructure, skilled manpower alongside inconsistent field performance and government policies. The solution to these challenges will significantly boost crop protection, food security, and sustainable agriculture in Nigeria.

The article presents an overview of the status, challenges, and prospects of current and emerging trends for the sustainable treatment and valorisation technologies of plastic wastes. The proliferation is ascribed to the growing population, living standards, and use of low cost, unbiodegradable, and chemically resistant plastic wastes in Nigeria. This scenario is exacerbated by the lack of comprehensive strategies for the collection, transport, segregation, and management of plastic wastes. Currently, plastic wastes treatment is accomplished by open-air burning, dumping, and landfilling. More advanced technologies, such as thermal (incineration, gasification), chemical (catalytic cracking and selective dissolution), and biological (microbial degradation) methods, are also utilized for treatment and valorisation. However, these high-cost, obsolete, and inefficient technologies result in GHG emissions, toxic fumes, toxins and leachates. Hence, novel technologies for the reuse, recycling, reduction, and valorisation of plastic wastes must emphasize energy, materials, and resource recovery. The article proposes the upcycling of plastic wastes into carbon nanomaterials (carbon microspheres, carbon nanofibers (CNFs), graphene flakes, carbon nanotubes), polymeric composite materials (wood-polyethylene composites, wood-fiber-reinforced plastics), biocrude/bio-oil, fuels, chemicals, and char through solvent/solvothermal treatment and plasma conversion. Solvent/solvothermal treatment can effectively treat and upcycle plastic wastes along with the removal of toxic, recalcitrant and bio-accumulative pollutants such as brominated flame retardants and organophosphorus flame retardants. However, the study identified numerous challenges that currently hamper plastic wastes disposal, management, and valorisation. Hence, sustainable and socially friendly approaches for plastic waste management and valorisation are required to address their short-and long-term impacts on human health, safety and the environment in Nigeria.

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