Dataset on Bubble Column with Commercial Fine-Bubble Diffuser: Effects of Surfactant Concentration and Air Flow Rates

This dataset accompanies the article “Surfactant Effects on Oxygen Transfer and Bubble Dynamics in a Fine-Bubble Diffuser Aeration Column” by Oscar Prades-Mateu et al. (2025). It contains the experimental data used to evaluate the influence of surfactant concentration and airflow rate on oxygen mass transfer in a bubble column equipped with a commercial fine-bubble diffuser. The experiments were conducted in a square bubble column with internal dimensions of 0.4 m × 0.4 m × 0.8 m, using a commercial fine-pore rubber diffuser (D-Rex model, Flexnorm membrane, OTT Group). The system was operated with deionized water and Sodium Dodecyl Sulphate (SDS) as the surfactant. Five surfactant concentrations were tested: 0, 2, 4, 6, and 8 mg/L, together with five airflow rates: 20, 40, 60, 80, and 100 L/min. All experiments were carried out at a water temperature of 13 ± 1 °C. For each condition (combination of surfactant concentration and air flow rate), the following key parameters were experimentally determined: Volumetric mass transfer coefficient (kₗa) — obtained from dynamic oxygen transfer experiments according to ASCE (1993) standard. Bubble size and shape — determined from high-speed image analysis (20 cm and 70 cm above the diffuser) and expressed as Sauter mean diameter (d₃₂). Gas holdup (ε) — derived from liquid height variation captured by a camera. Interfacial area concentration (a) — estimated from ε and d₃₂. Liquid-side mass transfer coefficient (kₗ) — calculated as kₗ = (kₗa)/a. The dataset is organized as follows: First CSV: figures_data_COLUMN.xlsx – Data from figures of the papers. Second CSV: bubble_size_distribution_COLUMN.xlsx – includes all measured and derived parameters for each combination of surfactant concentration and airflow rate. These data allow users to reproduce the main findings, validate correlations for gas holdup and mass transfer, and develop or benchmark predictive models for oxygen transfer in aeration systems influenced by surfactants. Keywords:Bubble column, Fine-bubble diffuser, Oxygen transfer, Surfactant concentration, SDS, Gas holdup, Bubble size, Mass transfer coefficient, Aeration efficiency