Mitigation of low methane content landfill gas through visible-near-infrared photocatalysis over Y2O3:Er3+/Graphene/TiO2
Abstract
Untreated low methane (CH4) content (less than 10%) landfill gas within the post-methanogenic stage is currently vented into the atmosphere, constituting an important source of anthropogenic greenhouse gas (GHG). Development of a proper mitigation process for low CH4 gas is therefore necessary for landfills. In this study a special photocatalyst, Y2O3:Er3+-TiO2-0.05% graphene (GR), was synthesized by sol-gel method and then characterized; it showed a good response to visible-near-infrared (Vis-NIR) sunlight. The corresponding absorption edge was 354 nm, and upconversion fluorescence peaks of ultraviolet (364 nm) and violet (408 nm) emissions were acquired under 980 nm excitation. Y2O3:Er3+-TiO2-GR was developed and tested for removal of low CH4 landfill gas under Vis-NIR light irradiation, and a maximum photodegradation rate of 45.1% for CH4 was obtained using the photocatalyst Y2O3:Er3+-TiO2-0.05% GR with a light intensity of 2050 mW m-2. The corresponding CH4 content decreased from 10% to 5.5%, mitigating almost half of GHG during the post-methanogenic stage. The intermediate products of CH4 degradation were CO, radOH, O-, CO2 and H2O traced by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). This research proposes a new approach for reducing the GHG effect of low CH4 content landfill gas.
- Publication:
-
Applied Surface Science
- Pub Date:
- October 2018
- DOI:
- 10.1016/j.apsusc.2018.06.138
- Bibcode:
- 2018ApSS..456..854T
- Keywords:
-
- Low CH<SUB>4</SUB> content landfill gas;
- Mitigation process;
- Photocatalyst;
- Upconversion;
- Graphene;
- Photodegradation mechanism of CH<SUB>4</SUB>