Removal of nitrogen containing hydrocarbons from wastewater by catalytic and non-catalytic hydrothermal oxidation, in sub- and supercritical conditions

The results of the hydrothermal oxidation of 1,8 diazabicyclo[5.4.0]undec-7-ene (DBU), a toxic nitrogen-containing organic compound by different processes is presented here. Subcritical experiments (wet air oxidation (WAO) and catalytic wet air oxidation(CWAO)), were conducted in a batch reactor and supercritical water oxidation (SCWO) experiments were conducted in a tubular reactor. The key operating parameters investigated were temperature, pressure, initial organic concentration; for catalytic experiments, the effect of catalyst metal loading and weight were also investigated. Commercially available Ru/Al₂O₃ pellets were selected for catalytic study after various catalysts were screened. Results indicated that temperature was the key operating parameter in all 3 processes that affected DBU removal, TOC removal and ammonia yield. Ru/Al₂O₃ pellets enhanced the DBU removal, TOC removal and decreased ammonia yield compared to WAO. Complete DBU removal was achieved by catalytic wet air oxidation and supercritical water oxidation. Kinetic data was acquired and a pseudo first order kinetic model was used to quantify the oxidation rate. WAO and CWAO were investigated for the treatment of hazardous industrial effluent with a high initial ammonia concentration and complete ammonia removal was achieved using Ru/Al₂O₃ pellets. A novel ruthenium coated reticulated foam monolith was investigated as an alternative for heterogeneous catalyst instead of Ru/Al₂O₃ pellets, the results show that it improved catalyst stability and could be an alternative to pellets for wastewater treatment.

Name dc:type.qualificationname

d_ph

Level dc:type.qualificationlevel

d_ph

Grantor dc:publisher.institution

University of Birmingham

Year dc:date.issued

2011

Author dc:creator

• Osibo, Oluwaponmile Olumayowa

• TP Chemical technology