Background and aims : Microorganisms are one of the most important sources of contamination in indoor air and occupational environments especially in hospitals. The aim of this study was to evaluate the adsorption characteristics of bone char to adsorb B. Subtilis in the air.

  Methods: In this study B.subtilis spores were used as a model of bacterial spores. Also bone char was used as an adsorbent in this study that was prepared by thermal method from waste bones and the characterization of prepared adsorbent was determined. Then the adsorption capacity of bone char for B.subtilis was evaluated.

  Results: The Present study show that bone char as a mineral adsorbent has high efficiency in adsorption of bacterial spores. The adsorption capacity of this mineral was 3698 spores per gram.

  Conclusion: bone char has a high capacity for adsorption of bacterial spores. Mineral structure of bone char can delay the reproduction and biofilm formation of microorganism on its surface. The result of this study could be used in development of control equipment of biological air pollutant.