A systematic review on employing thermochemical techniques for the production of exceptionally efficient biochar from discarded disposable diapers (D3)

The disposal of discarded disposable diapers (D3) is a critical eco-technological problem that is exacerbated by the exponential increase in global consumption each year. Global production of D3 is increasing exponentially and approximately 20 billion used diapers are sent to landfills each year, generating more than 3.5 million tonnes of diaper waste that requires almost 500 years to be fully decomposed. The disposal of D3 has resulted in significant environmental issues and public health hazards. The objective of this study was to provide a systematic review and in-depth discussion of the strategies, challenges, and recent breakthroughs in addressing the problems resulting from the generation and disposal of D3. A systematic literature search was conducted using three electronic databases (Google Scholar, Scopus, and ScienceDirect). Four peer-reviewed studies were selected from the 2287 articles found. Thermochemical technology is claimed to be suitable for the treatment and recycling of used diapers, especially with regard to the use of potentially safer and cleaner technologies with minimal costs. It was established that pyrolysis of D3 could yield useful end products with a wide range of applications, hence providing a future research direction to improve the efficiency of these processes in recycling this waste.