Modeling the electrocoagulation treatment of orthophosphate with aluminium electrodes

Abstract

Provedeno je istraživanje učinka elektrokoagulacijskog procesa s aluminijevim (Al) elektrodama na smanjenje masene koncentracije fosfata u vodi. Primijenjene su gustoće struje od 30, 75 i 150 A m-2 te inicijalna koncentracija fosfata od 27 mg/L (PO4-P). Postignuta je učinkovitost uklanjanja od 86% nakon 90 min rada reaktora s ugrađenim Al elektrodama pri gustoći struje od 75 A m-2 i uz inicijalnu koncentraciju NaCl od 2 g dm-3. Osim koncentracije fosfata (PO4-P), u komori elektrokoagulacijskog laboratorijskog pilot uređaja praćene su i promjene koncentracije otopljenog kisika (DO), te promjene temperature vode i pH. 3D numerički model primijenjen je za simulaciju polja strujanja i koncentracije fosfata u komori elektrokoagulacijskog uređaja. Modelom pronosa fosfata obuhvaćeni su procesi generiranja i taloženja flokula, te adsorpcije fosfata na flokule. Modelska parametrizacija temelji se na rezultatima mjerenja.The efficiency of the electrocoagulation (EC) process for the removal of phosphate (PO4-P) is analyzed using a batch pilot device with aluminum electrodes situated within the reactor. The applied current density at the electrodes (30, 75 and 150 A/m2) was the focus of the research. The initial PO4-P concentration is the same in all experiments (27 mg PO4-P/L). The concentrations of PO4-P and dissolved oxygen (DO), as well as the water temperature and pH, were measured in the batch chamber. The initial PO4-P concentration is reduced by 86 % after 90 min of reactor operation when the initial NaCl concentration is 2 g/L, while the current density is maintained at 75 A/m2. Additionally, a three-dimensional (3D) numerical model for PO4-P removal via the EC process is developed. By using the 3D numerical model, spatially continuous velocity fields and the PO4-P concentration were determined. Numerical model of PO4-P transport includes the processes of phosphate adsorption on flocculent, along with coagulated particles settling. Numerical model Parametrisation relies on the measurement results from the experiments made on batch pilot device