Abstract
The environmentally and economically friendly
2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidation
process requires recycling and/or recovery of chemicals.
In this work, hypochlorite recycling via electrolysis was
evaluated and potential means for TEMPO recovery were
explored. The most important variable affecting
electrochemical hypochlorite conversion was the
concentration of sodium chloride in the feed solution.
With 30 g/L NaCl salt, a sufficient hypochlorite
concentration of 0.8% could be obtained for pulp
oxidation of up to 5% consistency. The regeneration of
hypochlorite in the treated TEMPO solution was possible
by electrolysis and further oxidation performed with only
a small addition of make-up chemicals. During
electrolysis, some TEMPO degradation took place;
therefore, recovery of TEMPO should be done prior to
electrolysis. For the recovery of TEMPO, solid phase
extraction was tested. The best recovery of TEMPO was
obtained using a combination of hydrophobic solid phase
extraction SPE resin material and distillation (yields
between 52% and 87%).
Original language | English |
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Pages (from-to) | 6050-6061 |
Journal | BioResources |
Volume | 11 |
Issue number | 3 |
Publication status | Published - 2016 |
MoE publication type | A1 Journal article-refereed |
Keywords
- TEMPO oxidation
- recovery
- solid polymer phase
- electrolysis
- regeneration