The adsorption of a single pollutant can no longer meet the increasingly strict requirements of environmental governance. The easy loss and secondary pollution of powdered adsorbents further hinder the industrialization of adsorption technology. Through in-situ oxidative polymerization and hydrothermal deposition, polyaniline (PANI) and magnetic Fe3O4 nanoparticles were loaded onto a polyurethane (PU) matrix to prepare polyurethane-polyaniline /Fe3O4 (PU-P/F) porous composite loading materials, aiming to simultaneously remove multiple pollutants in wastewater and solve the problem of effective solid– liquid separation at the same time. The synthesized composite material exhibited a high specific surface area (30.08 m2/ g) and a hierarchical pore structure. Within a wide pH range (5–7), it showed a synchronous adsorption and removal effect on typical pollutants (ARG, Cr (VI), NO3 −-N, TP, MB, NH4 +-N) in printing and dyeing wastewater. Equilibrium can be reached within 0.5–2 h, following pseudo-second-order kinetics and Langmuir isotherm model, indicating mainly monolayer chemical adsorption. The continuous column adsorption regeneration test showed that for the simulated mixed wastewater, the continuous adsorption reached saturation after 660 min (53 chromatographic columns), while for the actual wastewater, the continuous column adsorption reached saturation after 535 min (43 chromatographic columns), and the efficiency remains after 8 regenerations. FT-IR and XPS confirmed the REDOX reaction between the –NH—group in polyaniline and Fe in Fe3O4, facilitating the adsorption and transformation of pollutants, while DFT calculations confirmed the strong interaction between polyaniline and anionic pollutants. This research provides ideas for solving the engineering bottleneck of adsorption technology.

Mechanistic insights into simultaneous adsorption of contaminants in dyeing wastewater using polyurethane-based hierarchical porous adsorbents
    Abstract
        Graphical abstract
    1 Introduction
    2 Materials and methods
        2.1 Materials
        2.2 Preparation of PU-PF porous composite material
        2.3 Instruments and characterization
        2.4 Adsorption experiments
            2.4.1 Static adsorption experiment
            2.4.2 Continuous column adsorption experiment
            2.4.3 Cyclic desorption and regeneration experiment
    3 Results and discussion
        3.1 Material characterization analysis
        3.2 Adsorption performance of PU-PF
        3.3 Continuous column adsorption
        3.4 Recycling performance of adsorbent
        3.5 Adsorption kinetic model analysis of PU-PF
        3.6 Adsorption mechanisms
    4 Conclusion
    Acknowledgements 
    References

• Nan Wang(School of Environmental and Chemical Engineering, Key Laboratory of Functional Textile Material and Product of the Ministry of Education, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China)
• Yihang Wei(School of Environmental and Chemical Engineering, Key Laboratory of Functional Textile Material and Product of the Ministry of Education, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China)
• Ning Wang(School of Environmental and Chemical Engineering, Key Laboratory of Functional Textile Material and Product of the Ministry of Education, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China, Center of Biological Resources Development and Pollution Control Universities of Shaanxi Province, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China) Corresponding author
• Yonghong Liu(School of Environmental and Chemical Engineering, Key Laboratory of Functional Textile Material and Product of the Ministry of Education, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China, Center of Biological Resources Development and Pollution Control Universities of Shaanxi Province, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China)
• Yunfeng Li(School of Environmental and Chemical Engineering, Key Laboratory of Functional Textile Material and Product of the Ministry of Education, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China, Center of Biological Resources Development and Pollution Control Universities of Shaanxi Province, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China)
• Hejia Sun(College of Physical Education, Xi’an Polytechnic University, Xi’an 710048, People’s Republic of China)