Work

Synthesis of Zn-doped MnO2 nanoparticles using Echinops Kebericho root extracts for photocatalytic application

Year: 2025

Type: article

Abstract: The discharge of effluents from industries containing persistent organic dyes such as methylene blue (MB) and methyl orange (MO) poses a significant environmental concern. Addressing this challenge requires sustainable, eco-friendly, highly efficient, and cost-effective treatment technologies. In this study, the Zn-doped MnO 2 NPs (Zn = 1 %, 3 %, 5 %M) were synthesized by a green route using Echinops Kebericho root extract, to evaluate photocatalytic degradation of methylene blue (MB) and methyl orange (MO). UV–Vis, SEM, XRD, FT-IR, and TGA characterized materials. Comparisons between undoped MnO 2 and 3 % Zn-doped MnO 2 NPs were used to assess optical and structural changes. The undoped MnO 2 (3.10 eV) and the 3 % Zn-doped sample (2.62 eV) showed a bandgap reduction, along with a slight crystallite-size decrease from 24.64 to 23.76 nm. SEM revealed irregular morphologies. In photocatalysis, MB degraded (95 %) at a catalyst dose (0.596 g), MB concentration (105 mg/L), and contact time (95 min); MO degraded (93 %) at a catalyst dose (0.557 g), MO concentration (48.3 mg/L), and contact time (142.6 min). Pseudo-first-order kinetics yielded R 2 = 0.996 for MB and 0.995 for MO. Isotherm modeling favored Langmuir adsorption (R 2 = 0.997 for MB and 0.996 for MO). Thermodynamics indicated ΔH° ≈ 30.283 kJ mol −1 (MB) and 30.38 kJ mol −1 (MO); ΔS° ≈ 45.54 J mol −1 K −1 for both dyes; ΔG° ≈ 30.24–30.34 kJ mol −1 K −1 T over the studied temperatures. The 3 % Zn-doped MnO 2 NPs demonstrated excellent stability and recyclability, retaining about 78 % MB and 76 % MO degradation after six cycles over six months. This study, green-synthesized Zn-doped MnO 2 NPs, especially at 3 % Zn, exhibit enhanced optical and catalytic properties and show strong potential as recyclable photocatalysts for degrading industrial dyes and other organic contaminants in wastewater.

Source: Results in Chemistry

DOI: 10.1016/j.rechem.2025.102860

Authors: Gada Muleta Fanta, Temesgen Gotse Gomera, Mamo Dikamu Dilika, Bedasa Abdisa Gonfa

Institutions: Arba Minch University, Adama Science and Technology University

Language: English

Topic: Advanced Photocatalysis Techniques

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

SDGs: Responsible consumption and production, Clean water and sanitation

Open Access status: gold

Estimated APC paid: $1,870