Urea removal in reclaimed water used for ultrapure water production by spent coffee biochar/granular activated carbon activating peroxymonosulfate and peroxydisulfate

This study evaluated the performance of spent coffee biochar (SCBC)/granular activated carbon (GAC) activating peroxymonosulfate (PMS) and peroxydisulfate (PDS) for urea degradation in reclaimed water used for ultrapure water production. Results showed that catalyst and oxidant wielded a great influence on urea removal. Of them, the GAC-PMS system could completely remove urea at the least oxidant (1 g/L) and catalyst dosage (0.2 g/L). GAC activating PMS mainly depended on graphite C structure and minor oxygen functional groups. However, the amounts of urea removed by 600BC-PMS and 900BC-PMS were 57% and 70%, respectively. In the PDS system, the urea removal through GAC-PDS could reach 90%, which mainly depends on the graphite C structure of GAC. Using the same conditions, the urea removal of 900BC-PDS was similar to GAC-PDS, so it has some potential as an alternative to commercial GAC.

Automated summary

The study evaluated the performance of spent coffee biochar and granular activated carbon in activating peroxymonosulfate and peroxydisulfate for urea degradation in reclaimed water. Different catalysts and oxidants had a significant impact on urea removal, with the GAC-PMS system proving to be the most efficient. The results showed that GAC activating PMS mainly depended on graphite C structure and minor oxygen functional groups.