Measurement of aluminum ions across the mordanting process of wool substrates with potassium aluminum sulfate and effluent characterization

Abstract

The purpose of this research was to determine the distribution of aluminum (Al) ions across mordanting procedures and characterize the effluent of wool challis fabric and wool yarn premordanted with potassium aluminum sulfate (PAS) at three concentrations (7%, 12%, 17%) by weight of fiber. ATSM D5673-16 Standard Test Method for Elements in Water by ICP-MS (American Society for Testing and Materials, 2016) measured the Al ions in the liquors and substrates. The effluent was characterized by measuring chemical oxygen demand (COD) and total organic carbon (TOC) by utilizing TNTplus®—Method 8000 and Shimadzu TOC-L Series. The Al percentage in the treated liquors for both substrates ranged from 26% to 68%. The findings met the Environmental Protection Agency Al in freshwater limits. The wool yarn absorbed a significantly lower percentage of Al than the wool challis. With the increase of the PAS mordant concentration, the percentage of Al ions detected in the substrates decreased significantly and the Al ions percentage significantly increased in the treated liquors. Thus, the 7% PAS concentration was significantly more efficient compared to the recommended 12% concentration. The TOC and COD values of the effluents met the Code of Federal Regulations for textile mill effluent discharge and Global Organic Textile Standard limits as output; however, dilution and neutralization are required before disposing of the effluents. This research confirmed the safe usage of PAS as a mordant for the selected wool substrates in terms of Al input, disposal with pH neutralization, and discharge standards. Further studies could investigate lower concentrations of PAS, the feasibility of reusing the treated liquors, and the impact of PAS amount to dye color parameters.