Fixed bed mycofilter column optimization and performance evaluation through the removal of a food coloring agent from an aqueous solution

Abstract

Mycofiltration via continuous fixed bed adsorption, helped to assess the effect of flow rate, pH, column bed height and myceliation on the sorption capacity of a mycofilter. The mycofilter (thatching straw and Pleurotus ostreatus) was cultured and loaded into polypropylene columns (2.5 × 12 cm) to bed heights of 2 and 4 cm. A food color solution was passed through at different pH (2 and 7.5) and flow rates (0.25 ml/min and 2 ml/min). The filtrate was collected and measured at time intervals. Under constant flow rate and solution pH, the 4 cm bed adsorbed 8 times the inlet amount of food color compared to 1.6 times only for the 2 cm bed. More food color was adsorbed with the higher flow rate (10 times the inlet concentration). Adsorption was only observed in the solution with pH = 2. The control filter (without mycelia) adsorbed 3-fold less than the mycofilter. The experimental data best fitted into the Thomas model (compared to the Yoon-Nelson model) which showed that an increase in bed height caused an increase in adsorption capacity (q_TH), and that an increase in flow rate resulted in an increase in Thomas rate constant (K_TH). FTIR analyses of the mycofilter revealed amide, hydroxyl, and chitin groups possibly involved in adsorption processes. Our fixed bed mycofilter optimally removed food color from aqueous solutions, in high bed height and flow rate, and low pH conditions.

Keywords:

• Biofiltration
• continuous flow adsorption
• fungal filter
• mushroom mycelia
• Mycoremediation

Acknowledgments

The authors would like to thank Dr R. Ngara, Ms S. Moloi, Mr N. Mzizi and Dr M. Mosoabisane from the University of the Free State (Departments of Plant Science, and Chemistry) for their technical assistance, and Mr Q Ngulube from Uppsala University (Department of Chemistry) for assistance with column modelling.

Disclosure statement

The authors report there are no competing interests to declare.

Additional information

Funding

This research forms part of a Water Resources Management Project funded by the Afromontane Research Unit, University of the Free State, South Africa [Entity number 2-119-C3353]. Sanele Mnkandla is supported by the Organization for Women in Science for the Developing World (OWSD) PhD Fellowship.