Scrap cast iron and copper-modified cast iron for reductive degradation of 2,4-dinitrotoluene

• Published in: Journal of chemical technology and biotechnology (1986) 2011-10, Vol.86 (10), p.1295-1302
• Main Authors: Fan, Jin-Hong, Wang, Hong-Wu, Wu, De-Li, Liu, Zhi-Gang, Ma, Lu-Ming
• Format: Article
• Language: English
• Subjects: 2,4‐dinitrotoluene reduction; 4-dinitrotoluene reduction; Applied sciences; Cast iron; Chemical engineering; Copper; Degradation; Dissolution; Electrodes; Exact sciences and technology; General purification processes; Pollution; Reactors; Reduction; Scrap; scrap cast iron; scrap copper-modified cast iron; surface aging; Waste water; Wastewaters; Water treatment and pollution; X-ray diffraction spectroscopy
• ISSN: 0268-2575; 1097-4660; 1097-4660
• DOI: 10.1002/jctb.2672

BACKGROUND: Little attention has been paid to the use of large‐sized scrap cast iron for reduction of refractory organic pollutants at neutral pH and in the presence of dissolved oxygen (DO). RESULTS: Scrap cast iron and copper‐modified cast iron with fresh surfaces have a high reactivity towards the reduction of 2,4‐dinitrotoluene (2,4‐DNT). The extent of conversion reached around 80% and 97% respectively, though it gradually decreased with repeated reactions to relatively stable values of 63% and 72%, and recovered once the reacted filings were cleaned by dilute acid. After 50 days reaction, no dissolved copper appeared in the copper‐modified cast iron process. The mass loss of copper due to physical detachment reached 1.1% of the total coated copper within the initial 20 reaction days, and only 0.3% appeared in the next 30 days. 2,4‐DNT oxidizes scrap cast iron to generate mainly FeFe2O4 with DO, however, it oxidizes scrap copper‐modified cast iron to generate mainly γ‐FeO(OH) and α‐FeO(OH). CONCLUSION: Both samples of cast iron were successfully applied in the treatment of neutral wastewater containing 2,4‐DNT with high reactivity and good repeatable efficiency. Electrode reaction rate was enhanced by the deposited copper, which has strong chemical and physical stability. Copyright © 2011 Society of Chemical Industry