Abstract:
The negative health and socio-economic impacts of emissions associated with domestic fuel burning are widely recognized. Although
there has been much progress in the provision of electricity to households in South Africa, many still rely on solid fuel sources such
as wood and coal. While various investigations have been done on reducing household emissions by reducing the use of polluting
fuels and improvements in combustion efficiency, comparatively fewer studies have been conducted on the reduction of emissions
through use of abatement technology. Catalytic oxidation could be utilized to oxidize particulate matter precursors such as volatile
organic compounds and soot particles to reduce secondary particulate formation. Although catalytic methods have not been
effectively utilized in practical domestic applications, studies have shown effective soot reduction during laboratory testing. This
study investigated the synthesis and use of a manganese oxide based catalyst to reduce particulate matter from domestic fuel burning
stoves. The catalyst was synthesized onto a mesh substrate and inserted into the flue of the stove. During field testing, the presence of
the catalyst increased the mass of particulate matter collected onto PTFE filters used for gravimetric analysis, with Scanning Electron
Microscopy (SEM) analysis showing spherical particles in the pores of the filters used during the catalytic runs. The baseline runs
had very few of these particle clusters. Energy Dispersive X-Ray (EDX) analysis of the catalyst run filters did not detect manganese,
revealing that increased particulate concentrations were not as a result of macroscopic particles of the catalyst being dislodged from
the support. Dislodgement of very small metal particles from the catalyst could, however serve as nucleation nodes for particle growth
which would have a non-metal coating leading to the non-detection of manganese. The increase in particulate matter could also be
caused by the impingement of particulate matter precursors on the catalyst followed by particle growth and dislodgement into the
flue gas. The testwork showed that an active catalyst can be synthesized onto a mesh catalyst support in a relatively simple and costeffective
manner, which can be utilized in domestic fuel burning devices. It is recommended that a range of optimized, potentially
active catalysts be tested to improve the oxidation of particulate matter precursors to carbon dioxide.
