A two-parameter model for the determination of the partition coefficient for TRS in a culture medium

Abstract

A two-parameters model was applied for the determination of the activity coefficient for a culture medium, and compared with Henry's law, the extended UNIQUAC, and experimental data obtained from an experimental setup system, consisting of a liquid culture media Thiobacillus (ATCC 290) with hydrogen sulfide (H₂S), dimethyl sulfide (DMS), methyl mercaptan (MM), and dimethyl disulfide (DMDS), respectively.

 The ANOVA indicates that the use of Henry's law is not appropriate for MM and H₂S with R²_adj values of -106.15% and -53.33%, respectively. The extended UNIQUAC model and the two-parameter model were able to describe the system with values of 76.94% and 94.15% for DMS and DMDS in the case of UNIQUAC Extended, respectively, and 88.50% and 98.08% using the two-parameter model.

These results show that the two-parameter model is able to describe the system, using a low number of parameters. However, the extended UNIQUAC shows better results but presenting a high level of over-parameterization. Henry's law showed significant deviations, not being representative of all analyzed cases.

 The two-parameter model is presented as an alternative to describing systems in which vapor-liquid mass transfer is involved in culture media, providing a better approximation than traditional models and lower calculation costs than complex models.