ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Utilization of olive mill solid waste-based activated carbon for the effective elimination of phenolic compounds in olive-mill wastewater: a study on optimization, kinetics, and isotherms

Aboubacar Sidigh Sylla, Aziz Ihammi, Ilham Kirm, Abdelghani Boussetta, Kamal Benali, Tarik Ainane, Nour-Eddine El Mansouri, and Mohammed Chigr

Laboratory of Molecular Chemistry, Materials and Catalysis, Faculty of Sciences and Technology, Sultan Moulay Slimane University, Beni-Mellal, Morocco

E-mail: azizihammi@gmail.com

Received: 26 February 2025  Accepted: 25 February 2026

Abstract:

Olive mill wastewater (OMW) poses a significant environmental challenge due to its high organic and phenolic content. This study explored the use of activated carbon (AC) derived from olive mill solid waste (OMS) as an adsorbent for removing phenolic compounds (PCs) from OMW. The preparation of AC was optimized using response surface methodology (RSM), focusing on activating agents (KOH, ZnCl₂, and H₃PO₄), activation temperatures (600–800 °C), and impregnation ratios (2–4). Results revealed that ZnCl₂ was the most effective activating agent, producing the highest iodine number of AC. The optimal conditions for ZnCl₂-activated carbon (ACZ) were achieved at 700 °C with a 4:1 impregnation ratio. The ACZ and raw OMS were characterized using TG/DTG, ATR-FTIR, SEM, and XRD analyses. Batch adsorption experiments were conducted to assess the removal of PCs from OMW, examining factors such as pH, contact time, adsorbent dose, initial polyphenol concentration, and temperature. The adsorption data aligned well with the Langmuir isotherm model (R² = 0.990) and the pseudo-second-order kinetic model (R² = 0.990), suggesting chemisorption as the primary mechanism. Desorption studies using hydrochloric acid (HCl) recovered 68% of adsorbed PCs in the first cycle and 20% in the second cycle. The comprehensive characterization and adsorption performance of the ACZ demonstrate its potential as a sustainable and efficient adsorbent for OMW treatment, offering the potential for agricultural waste valorization and environmental pollution mitigation.

Graphical abstract

Keywords: Pyrolysis; Response surface methodology; Polyphenols; Adsorption; Desorption

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04772-y

Chemical Papers 80 (6) 6381–6399 (2026)