No abstract

The demand for biochar has increased over time due to its wide range of applications in various industries. Biochar, which is the solid product of the thermochemical conversion of biomass, has been synthesized using different reactor‐based technologies. One such technology is top‐lit updraft (TLUD) technology. This study is a review of published literature that discusses trends in the utilization of the TLUD technology, focusing on biochar production. This study also evaluated the principles of TLUD technology. The properties and applications of TLUD‐based biochar were also discussed. In comparison with other technologies, TLUD technology is characterized by higher thermal efficiency, simplicity of starting the fuel, low smoke emission, and high biochar yield. It was observed that the use of TLUD technology resulted in the production of high‐quality biochar with a variety of characteristics, which has been utilized as an adsorbent for wastewater treatment, in the agricultural sector to increase soil nutrients, and as a solid fuel. The concept of semi‐batch‐fed TLUD technology was also introduced in this study to enhance the efficiency and output of the batch‐fed TLUD configuration that has been in use. Some knowledge gaps in the study could be addressed by future studies on the use of this technology.

The COVID-19 pandemic encouraged the use of plastic-based personal protective equipment (PPE), which aided greatly in its management. However, the increased production and usage of these PPEs put a strain on the environment, especially in developing and underdeveloped countries. This has led various researchers to study low-cost and effective technologies for the recycling of these materials. One such material is disposable facemasks. However, previous studies have only been able to engage electrically powered reactors for their thermochemical conversion, which is a challenge as these reactors cannot be used in regions with an insufficient supply of electricity. In this study, the authors utilized a biomass-powered reactor for the conversion of waste disposable facemasks and almond leaves into hybrid biochar. The reactor, which is relatively cheap, simple to use, environmentally friendly, and modified for biochar production, is biomass-powered. The co-carbonization process, which lasted 100 min, produced a 46% biochar yield, which is higher than previously obtained biochar yields by other researchers. The biochar thus obtained was characterized to determine its properties. FTIR analysis showed that the biochar contained functional groups such as alkenes, alkynes, hydroxyls, amines, and carbonyls. The EDX analysis revealed that the biochar was primarily made of carbon, tellurium, oxygen, and calcium in the ratios of 57%, 19%, 9%, and 7%, respectively. The inclusion of the facemask decreased the surface area and porosity of the biochar material, as evidenced by its surface area and pore characteristics.