Thermal regeneration of powdered activated carbon (pac) and pac-biological sludge mixtures
1983; Elsevier BV; Volume: 17; Issue: 9 Linguagem: Inglês
10.1016/0043-1354(83)90053-2
ISSN1879-2448
AutoresDennis Clifford, P. Chu, Arthur P.S. Lau,
Tópico(s)Supercapacitor Materials and Fabrication
ResumoA temperature-programmed graphite microfurnace apparatus with mechanical stirring is described for the thermal regeneration of powdered activated carbon (PAC) alone or PAC-biological sludge mixtures from the PAC enhancement of the activated sludge process. Three PACs with widely differing BET areas were evaluated to determine the effects of regeneration on their physical and chemical properties. PAC weight % recoveries were in the range of 60–80%, and the recovery of wastewater (filtered mixed liquor) adsorption capacity regularly exceeded 100% for all carbons. In one case, 222% recovery was achieved. Regeneration always reduced BET area but the effects on I2 number, pore size distribution and particle size were mixed. Compared to the regeneration of PAC alone, the presence of 40–50% biological sludge was clearly detrimental to the regeneration process. Nevertheless, essentially complete regeneration could be achieved with biomass present by adding a 20-min 400°C, N2-purge-gas charring step to the usual 20-min, 825°C, H2O-N2-CO2 purge-gas reactivation step. Unfortunately, charring the biomass produced a regenerated material containing 27–34% inerts including carbonaceous char and mineral ash. This black inert material was quite insoluble in dilute HCl and had no useful adsorption capacity. The controlled application of H2O or trace amounts of O2 during charring is suggested for the minimization of detrimental char but further research is needed.
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