Effect of Microplastics Pollution on Hydrogen Production from Biomass: A Comprehensive Review

Hydrogen production from biomass and organic wastes is considered as a potential alternative energy source and is known as a clean and CO2-free fuel energy carrier. H2 is considered very promising among the other energy sources; therefore, the effective conversion of biomass and organic solid waste to this secondary energy source is urgently sought. As a result, it is of importance to assess the impact of the existence of microplastics (MPs) pollution in biomass during its fermentation. It was found that, besides the number of plastic particles present in biomass, the size of them plays the most important role in the yield of hydrogen. While plastics in nanoparticle sizes always suppress the production of H2, depending on their concentration, MPs may increase or reduce it. For example, the presence of 60 particles/L of micrometer-sized polyethylene terephthalate reduces hydrogen production by 30%, while 200 particles of it yields 63.6% more hydrogen. This Review examines all available literature on the effects of the presence of various MPs on biohydrogen production.