Measurement of Aluminum and Chemical Oxygen Demand in the Effluent of Mordanted Cotton Against Environmental Regulations

Despite toxicity concerns of chemical mordants used in natural dyeing, there is limited research on the measurement, quality, and safe disposal of the chemical mordant effluent. This study measured the aluminum ions across the premordanting process of cotton print cloth using inductively coupled plasma mass spectrometry and calculated the oxidizable organic matter in the effluent through chemical oxygen demand (COD). The amount of aluminum absorbed by the cotton print cloth was low (2.31%–5.16%). The effluent COD was 23.91g COD/kg. Upon neutralization of the acidic condition, the aluminum in the effluent met discharge to freshwater regulations, and the COD met discharge to U.S. municipal sewage systems. However, the Global Harmonized System restricts aluminum acetate dibasic from organic certification due to its boric acid content. The high mordant concentration in the effluent supports the reuse of mordant baths but not direct disposal to the land or standing waters.