Comparative study of biofiltration system efficiency with different substrates in hydrogen sulfide removal: A systematic review

Background and Objective: Biofiltration, which is a relatively new technology for controlling air pollution, is known as a method to remove unpleasant odors, volatile organicsubstances and toxic gases from industrial activities. This has been due to low operating costs, low energy consumption and no waste that needs to be recycled. Gaseous hydrogen sulfide is highly toxic and corrosive and is one of the main causes of air pollution and acid rain, which causes a lot of human and financial losses to human societies every year. Since the treatment of air polluted with this gas by physical, chemical and biochemical methods has high costs and also leads to the production of hazardous wastes, the purpose of this study was a systematic review of published studies on the efficiency of biofiltration systems with The substrates were different in removing the polluting gas of hydrogen sulfide from the air stream.Materials and Methods: In this study, a systematic review of all articles published in English from ۲۰۰۰ to September ۲۰۲۱ about the efficiency of biofiltration systems with different substrates in the removal of hydrogen sulfide were examined. These articles are searched through databases Science Direct, Scopus, Web of Science, proquest, PubMed and Google scholar, using keywords such as "biofiltration", "biofiltration substrates", "substrates", "hydrogen sulfide", "hydrogen sulfide removal", "Desulfurization" were obtained. Endnote X۷ software was used to organize, study titles and abstracts, and identify duplicates.Results: From a total of ۱۲۹۵ articles obtained in the initial search of sources, ۶۵ studies were included in the study according to the inclusion and exclusion criteria. Considering and comparing the performance of different substrates in the biofiltration system for the removal of hydrogen sulfide, it can be concluded that the polyurethane foam substrates, lava rock (cooled volcanic lava), biofilm and microbial mass, dry sludge and activated carbon have the highest efficiency (۱۰۰%) in removing this polluting gas and are more successful. Also, based on the results of the study, it was found that the biological system using Thiobacillus thioparus, in addition to showing acceptable efficiency in the removal of hydrogen sulfide, has less contamination and due to its low cost, easy control and maintenance is one of the best methods. Conclusion: In comparison, biofiltration is much more economical than other methods, especially when treating large volumes of air with low concentrations of biodegradablepollutants. However, more research is needed to understand the metabolic degradation pathways of gaseous pollutants, the effective mass transfer between liquid and gas phases, and better modeling methods that include better kinetic data.

Keywords:

Biofiltration , substrates , Hydrogen Sulfide , efficiency , Air Pollution Control