De-emulsification of bilge water by cupro-Fenton reaction

INCHAURRONDO, N.; CORTI-MONZÓN, G.; CARACCIOLO, P.; MURIALDO, S.

CABA

Congreso; CIBIQ2023 - II IBEROAMERICAN CONGRESS OF CHEMICAL ENGINEERING; 2023

Asociación Argentina de Ingenieros Químicos (AAIQ)

Bilge water is a complex shipboard wastewater composed of seawater, various fuels, lubrication oils, cooling water, and other pollutants. A major part of oil in bilge waters is emulsified, so the physical methods may fail to satisfy the targeted treatment levels. Therefore, this study focuses on the evaluation of the cupro-Fenton reaction for the de-emulsification of bilge water. This process is based on the reaction of Cu species with H2O2 to generate highly oxidizing species over a broader pH range compared to traditional Fenton. Due to the variability of bilge water, a model emulsion was prepared according to the International Maritime Organization (IMO) [1]. In our case, NaCl was also added up to 5000 ppm Cl- unless otherwise specified. Fenton reaction was carried out at room temperature for 5 h, using a tube rotator. The reaction was monitored by measuring total carbon (TC) (TOC analyzer, Shimadzu) and H2O2 concentration (iodometric titration). The stoichiometric H2O2 dose was fixed considering C as the measured total carbon, following the reaction: C + 2H2O2 → CO2 + 2H2O. According to the results, the cupro-Fenton reaction successfully de-emulsificates the model emulsion. A phase separation is observed. The reactive oxygen species generated may demulsify stable bilge emulsions by degrading organic compounds, such as surfactants [2]. The presence of salts enhances the process by altering the packing of surfactant molecules at the droplets surface, thereby enhancing the contact between oxidants in the aqueous phase and oily species inside the droplets [2]. Moreover, when ionic strength increases, the electrostatic shielding between droplets is reduced, allowing droplet interaction. Higher Cu doses increase de-emulsification but secondary copper pollution should be dealt with. It is important to highlight that transition metals such as Cu may commonly appear in bilge waters, which helps the implementation of the cupro-Fenton technology.