Synergistic Improvement of Photoactivity in Rare Earth-Doped Hierarchical ZnO Microspheres for Palm Oil Mill Effluent Treatment and Synchronously Biogas Generation

Abstract:

The remediation of palm oil mill effluent (POME) presents a considerable hurdle for Malaysia’s palm oil mill, requiring fulfillment with the environmental regulations before discharge. This work demonstrated a semiconductor-mediated photocatalytic technology to treat POME and synchronously evaluated the biogas generation. X-ray diffraction findings indicated that the fabricated ZnO product possessed wurtzite as a major crystalline phase. Its band gap energy was measured to be 3.27 eV via a UV-vis diffuse reflectance spectroscopy technique. The hierarchical ZnO microsphere morphology assembled by lots of layered nanosheets was observed via field-emission scanning electron microscopy. Under UV irradiation, the as-fabricated ZnO product displayed an enhanced photoactivity in comparison to the commercially available TiO₂ in treating the POME. Moreover, the ZnO/Ce and ZnO/Eu were also fabricated and showed greater photocatalytic efficacy after doping the rare earth ion in ZnO. Remarkably, the evaluation of biogas generation depicted that the ZnO/Ce and ZnO/Eu photocatalysis produced a greater quantity of CH₄ and CO₂ after 360 min irradiation. The work offered an environmentally friendly and efficient photocatalytic technology via ZnO/RE in treating wastewater and synchronously generating renewable energy.

• Periodical: Solid State Phenomena (Volume 377)
• Pages: 67-72
• DOI: https://doi.org/10.4028/p-T31yVg
• Online since: October 2025
• Authors: Jin Chung Sin*, Sze Mun Lam, Jin Han Tan, Hong Hu Zeng
• Keywords: Biogas, Cerium, Doping, Europium, Photocatalytic Wastewater Treatment, ZnO

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