An Integrated Screening Study of Polyphenol Recovery from Olive Mill Wastewater Using Cationic Starch-Assisted Clarification and Adsorption Resin Purification.

Olive mill wastewater (OMW) is an environmentally problematic effluent but also a rich source of antioxidant phenolic compounds. This study evaluated an integrated recovery approach combining cationic starch clarification and adsorption resin purification for obtaining phenolic-rich fractions from Dalmatian OMW. A pooled OMW sample was characterized for conventional wastewater parameters and total phenolic content (TPC), clarified with four commercial cationic starches, and subsequently processed using Seplite LXA84, Seplite LXA88, Seplite LXA816, and Amberlite XAD4 adsorption resins. PrimePHASE 2545 at 1000 mg active substance L-1 provided the most favorable balance between matrix removal and phenolic retention, reducing suspended solids and organic load while preserving approximately 92% of the initial TPC. In the preliminary resin screening, Seplite LXA84 produced the most favorable ethanol eluate, with the highest phenolic recovery and strong antioxidant activity, particularly in FRAP and ORAC assays. HPLC profiling confirmed hydroxytyrosol as the dominant recovered phenolic compound, accompanied by tyrosol and selected phenolic acids. These findings support a two-stage OMW valorization approach in which cationic starch pretreatment improves the suitability of OMW for column processing, while resin adsorption produces phenolic-rich fractions with antioxidant activity that may serve as candidates for further purification, characterization, and application-oriented research.