Phosphorus and COD removal from chemically and electrochemically coagulated wastewater

Abstract

Wastewater coagulation and electrocoagulation were investigated as sorption processes involving colloidal sorbents such as (Al(OH) 3) n , (Fe(OH) 3) m and (Fe(OH) 2) p. An attempt was made to fit experimental data to two popular sorption models. Based on a statistical and mathematical analysis of the obtained results, the Langmuir model of chemical adsorption was regarded more probable than the Freundlich model. The highest maximum adsorption of phosphorus in the analyzed wastewater was achieved with the use of PIX, and the lowest adsorption maxima were reported for an iron electrocoagulant. PAC was most effective in reducing COD of wastewater. PAC and PIX delivered higher adsorption maxima for compounds responsible for COD than aluminum and iron electrocoagulants.

Archives of Environmental Protection

“…OHions compete with PO 4 3for Fe 3+ ions and, at the same time, sorption processes can proceed (Li et al 2009). Smoczyński et al (2014) found that the main mechanism of phosphorus removal in the chemical and electrochemical coagulation processes is the chemical sorption process (chemisorption); as a result, covalent bonds are formed between the adsorbate particles and the adsorbent -hydrolysed metal species surface.…”

“…It is possible to obtain the assumed permissible concentrations for phosphorus in wastewater discharged from wastewater treatment plant after applying either biological dephosphatation or chemical precipitation methods using coagulants, i.e., aluminium or iron(III) salts (Gu et al 2011;Zou and Wang 2017). Chemical coagulation is also initiated by the dissolution of metals in the electrocoagulation process after an electric current was applied to the electrodes (Smoczyński et al 2014). A source of metals in the solution may also be a galvanic cell built of electrodes of steel (anode) and carbon (cathode), immersed in an electrolyte (Yuan et al 2009).…”