Non-woven fabric activated carbon produced from fibrous waste biomass for sulphur dioxide control

Waste fibrous biomass (flax) has been processed using non-woven textile techniques to produce a fibrous fabric material. The biomass fabric was then processed to produce activated carbons which retained their structure and flexibility. The carbons produced in a range of process conditions possessed a range of different surface areas and porosities. The activated carbons produced by chemical activation at different temperatures had high surface areas, ranging from 126 m² g⁻¹ for the activated carbon produced at 450 ºC to 1177 m² g⁻¹ produced at 800 °C activation temperature. At increased hold times at 800 °C the surface areas increased further, for example reaching 1656 m² g⁻¹ at 2 h hold time. The activated carbons were found to be very microporous, containing very small micropores. The produced activated carbons were then investigated in terms of the removal of sulphur dioxide in a bench scale continuous flow reactor. The SO₂ adsorption results showed that for the waste biomass fibre carbons, uptake of SO₂ from the gas stream was found to be dependent on the degree of activation. As the micropore volume and surface area of the samples increased, the SO₂ adsorption capacity also increased, observing a linear relationship. The adsorption of SO₂ by the waste derived activated carbons was significantly higher when compared to commercially obtained activated carbons. This appeared to be related to the pore size distribution of the samples, with the waste biomass activated carbons possessing a greater number of ultra-micropores than the commercial samples. Increase in the temperature of the activated carbon bed led to a marked decrease in the adsorption of SO₂. Uptake of SO₂ was also shown to be dependent on the concentration of the SO₂ inlet feed gas, where higher SO₂ concentrations led to enhanced uptake. The advantages of using textile processing techniques to produce a non-woven fabric activated carbon enabling different forms to be produced related to the end-use application has great potential for resource recovery.