Effect of sound waves and inclination of membrane on the performance of the osmotic microbial fuel cell

Abstract

This study aimed to explore the effect of the sound wave and membrane inclination i.e., 45° and 90° (MI45 and MI90) on the performance of osmotic microbial fuel cell (OMFC). The vibrations were given by a sound intensity of 60–80 dB and 20–1000 Hz in an anode compartment for a period of 5–6 h per day. Membrane inclination was given to maximizing the effective surface area under a fixed plane without changing its volumetric capacity to enhance water flux. Membrane inclination increased the effective surface area up to 33.33%, therefore, water flux was increased by 10% by using 45° inclination. The OMFC produced maximum water flux, reverse salt flux and power density of 0.750 ± 0.02 and 0.666 ± 0.02 Lm^-2h⁻¹, 3.18 ± 0.02 and 3.10 ± 0.02 gm^-2h⁻¹, 35.22 ± 12 and 24.22 ± 08 mW.m⁻² for MI45 and MI90 respectively with the effect of sound. The chemical oxygen demand (COD) removal was found 66.85 ± 1% and 59.51 ± 1% with and without the effect of sound. Therefore, sound reduced the OMFC start-up time by 2–3 days based on open-circuit voltage data and also increased the anaerobic degradation by 6–9%. Overall, sound stimulates bacterial growth for the degradation of organic matter, and membrane inclination gives a more effective surface area for water flux.