Basic research on the cleaning mechanisms of filters made of hardened cement paste in the treatment of wastewater from the textile industry

• Applicants: Professorin Brigitte Helmreich, Ph.D.; Dr. Harald Hilbig
• Subject Area: Construction Material Sciences, Chemistry, Building Physics
• Term: from 2022 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 495389990

Wastewater from the textile industry is an acute environmental problem and contributes significantly to global water pollution. Especially wastewater deriving from the dyeing industry is a challenge: it contains often a wide variety of organic dyes and large amounts of salt. Conventional wastewater treatment methods are not sufficient in treating such complex wastewater while more advanced processes are often very expensive. In particular, emerging countries who generate the majority of textile wastewater are looking for cost-effective treatment methods.The aim of the research project is the fundamental investigation of the surface interactions of hardened cement paste (HCP) with dyes used in textile industry and the development of an inexpensive adsorption filter based on HCP. The discoloration processes identified in our preliminary work on HCP surfaces containing ground granulated blast-furnace slag (GGBS) should be examined in more detail in order to gain a better understanding of the underlying mechanisms. A combination of different analytical methods should clarify whether the discoloration is purely a matter of adsorption processes on the HCP surface or whether degradation or metabolism processes also play a role.First, three different dyes with various functional groups and of different polarity, common in textile industry are used in batch tests to classify of HCPs with different amounts of GGBS with regard to their decolorizing performance. The optimal composition of the binding agents with regard to the interaction with the examined dyes and coloring salts is then used for the development of a filter material. Using column tests, its cleaning performance is tested under various reaction conditions (pH value, electrical conductivity, contact time) and optimized in terms of application.The vision is to develop a cost-effective filter granulate, which can be produced on site and enables the treatment of dyes from textile waste water, especially such containing both dyes and dye salts.

• DFG Programme: Research Grants