Characterization of phosgen‐free MIC wastewater

Abstract

A high strength wastewater containing persistent compounds is generated from the phosgen‐free MIC(methylisocyanate) process. To get some basic information prior to developing effective treatment methods, the wastewater was characterized by identifying the components, evaluating their biodegradabilities, and toxicities. Four components were extracted from the wastewater and found to be tirmethylisocyanurate (TMIC), trimethylbiuret (TMBU), dimethylurea (DMU), and tetramethylurea (TMU) by comparing the GC‐MS and FTIR spectra of them with those of the proposed authentic compounds. Their toxicities by Microtox test were not so serious that their effect on the aquatic environment were expected insignificant. The biodegradability test results showed that TMIC, TMBU and TMU were rarely degraded biologically while DMU was readily decomposed releasing ammonia as a metabolite.

Key words:

• phosgen‐free MIC wastewater
• identification of wastewater components
• toxicity
• biodegradability