Hydrogen production from human and cow urine using in situ synthesized aluminium nanoparticles

Hydrogen production from wastewater system has the potential to add a new dimension to the energy economy. Urine is an abundant waste and contains about 90-96% of water. While there have been efforts to generate electricity from urine (using microbial fuel cells), direct hydrogen production from urine using any technique is less explored. We report human and cow urine pretreatment with simultaneous hydrogen production using a simple redox reaction. This is achieved via in situ formation of aluminium nanoparticles in urine through reduction of aluminum salt using sodium borohydride; the key novelty of the process is the use of Al salt/NaBH4. The in situ prepared aluminium nanoparticles instantly react with urine to produce hydrogen. The volume of hydrogen produced is observed to be sensitive to pH, amount of Al salt, and ageing (storage time of urine). Interestingly, ageing does not impact the kinetics of initial hydrolysis in cow urine as much as it affects in the case of human urine. Fresh urine is found to be better in both the cases. Total carbon, total organic carbon, total nitrogen and total phosphorus removal efficiencies are found to be a maximum of 69.93%, 71.88%, 64.16% and 50.9% respectively for human urine; these values are 67.8%, 70.1%, 61.3% and 48.9% for cow urine at pH 3. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study introduces a method of simultaneous hydrogen production from urine by in situ formation of aluminum nanoparticles through a redox reaction. The volume of hydrogen produced is sensitive to pH, amount of Al salt, and ageing, with fresh urine showing better results.