Year: 2026
Type: article
Abstract: This research evaluates unmodified palm kernel cake (PKC), an agricultural by-product of palm oil processing as an inexpensive and sustainable adsorbent in the removal of methylene blue (MB) in aqueous solutions. Experiments on batch adsorption were carried out at 298–313 K, 5–20 mg/L of initial MB concentration, and 2–8 pH. The highest removal of 81% was obtained at pH 8 within 90–120 min. The Langmuir isotherm (R2 = 0.982) provided the best fit, yielding a theoretical maximum monolayer capacity (qm) of 151.5 mg/g; the experimentally measured adsorption capacity (qe,exp) was 4.8 mg/g under the tested conditions. Pseudo-second-order kinetics (R2 = 0.999) best described the adsorption rate, indicating intraparticle diffusion controlled physical adsorption confirmed by an activation energy of 37.8 kJ/mol. Thermodynamic analysis revealed a spontaneous (ΔG° = − 3.98 to − 4.25 kJ/mol), endothermic (ΔH° = 1.47 kJ/mol) process. The adsorption process is mainly physical, which depends on the electrostatic attraction, hydrogen bonding, π–π stacking, and intraparticle diffusion as shown in the Weber-Morris, Boyd, FTIR, and SEM analyses. PKC maintained a high adsorption efficiency of 96.5% even after four regeneration cycles, which showed great reusability and high potential of sustainable treatment of textile wastewater.
Source: Scientific Reports
Language: English
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,690
Funder: Universiti Malaysia Sabah
OpenAlex ID: W7147430235