A Polarity-induced Surfactant/Tertiary Amine System Evolving into Water Treatment Materials

Abstract

Abstract By polarity modification and controlling a suitable hydrophobicity-hydrophily balance towards quaternary ammonium salt surfactant, it was first observed that the formed polarity-induced quaternary ammonium salt surfactant/tertiary amine system, was directly endowed with the functional characteristics of water treatment. This broke through the functional bottleneck of existing surfactants that could not be used as water treatment materials. When treating a dyeing wastewater, the polarity-induced quaternary ammonium salt surfactant/tertiary amine system achieved 95.26–99.89% of dye removal percentages in a wide range of dosages (80–150 mg/L), both the water treatment efficiency and stability were strong, and it was suitable for multi-element combination with other inorganic flocculants and coagulants to promote rapid sedimentation of flocs and achieve rapid elimination of turbidity within 30 min. Moreover, the serial kilogram-grade scale-up tests in synthesis and application were adopted to verify the practicability of products, beyond the status quo that the current developments of water treatment materials were usually carried out in small-scale experiments. The simulated scale-up tests of 50g-3kg synthesis reactions were carried out, and the results showed that all levels of scale-up reactions had given the stable reaction temperatures without any strong exothermic runaway phenomenons, and the dye removal percentages for scale-up products to treat dyeing wastewater were 92.08–99.94% in the dosage ranges of 90–200 mg/L, which were close to that of the small-scale product applied, indicating that the product was suitable for scale-up production and maintained the superior performance. In addition, the amplitude flow settling tank model was introduced to carry out the application simulation scale-up tests for treating a 90 kg dye wastewater. The results showed, after 30 min, the dye removal percentage of the outlet water was above 98.51%, and the turbidity value was below 6.9 NTU, which reached the first-class discharge standard and were superior to the small-scale beaker test results. Therefore, the scale-up application performance was also superior, confirming that it was feasible for the practical engineering application. In conclusion, this study pioneered a new route with extremely easy scale-up production and engineering application to select useful water treatment materials in water treatment field.