## 1 Introduction  
The rapid development of the social economy and urbanization has significantly enhanced the living standards of both urban and rural residents. Nevertheless, this progress has concurrently led to a substantial and accelerated increase in domestic and municipal solid waste generation [1, 2, 3]. It is anticipated that the global amount of domestic waste will reach 2.2 billion tons by the year 2025 [4, 5]. The principal waste disposal methodologies encompass landfilling, incineration, and composting, with landfilling remaining the predominant global choice due to its operational simplicity and cost-effectiveness. This technology's logistical advantages and economic viability have established it as the cornerstone of contemporary municipal solid waste management systems [6, 7]. While sanitary landfills offer significant waste management advantages, they inevitably produce landfill leachate as a byproduct [3, 8, 9]. Landfill leachate is the main secondary pollution product of landfills [10, 11], and originates from complex biogeochemical transformations of waste materials. The formation mechanism involves synergistic hydrological interactions (precipitation infiltration and groundwater intrusion) coupled with biochemical degradation processes (physical compaction, chemical dissolution, and microbial decomposition), ultimately generating this recalcitrant wastewater containing elevated concentrations of organic and inorganic contaminants [12, 13]. This contains toxic heavy metals, organic pollutants, pathogens, and inorganic salts with pollutant levels often several orders of magnitude higher than those found in domestic sewage [4, 14, 15]. These pollutants contaminate surface water, groundwater, soil, etc., posing a serious threat to ecosystems, plants, animals, and human health [16; 17; 18]. Furthermore, toxicity analyses using various test organisms (_Vibrio fischeri, Daphnia magna, Artemisia salina, Phragmites_, etc.) have confirmed the potential hazards of landfill leachate [19; 20; 21; 22; 23]. Consequently, there has been an increasing emphasis on the disposal of landfill leachate in recent years, particularly in urban areas [24; 25; 26; 27]. Although research on landfill leachate has increased since 2016, it is crucial to develop economical and environmentally friendly disposal technologies [28; 29]. In recent years, various methods for purifying landfill leachate have become a hot research topic, including physical, chemical, and biological technologies [30]. However, with the advancement of analytical technologies (such as high-resolution mass spectrometry (HRMS)) [31], an increasing number of previously undetected pollutants in landfill leachate are being identified [32], and these pollutants are defined as emerging contaminants (ECs). ECs encompass a wide range of substances, including pharmaceuticals, endocrine-disrupting compounds, nanomaterials, microplastics, and industrial chemicals, which significantly increase the complexity and difficulty of landfill leachate treatment [33]. Single methods have certain limitations and cannot completely purify the landfill leachate. Physical methods, such as adsorption, are beneficial for removing small molecular weight organics, but they are not suitable for removing large molecular weight contaminants (such as humus) in landfill leachate [34]. Biological methods are widely used to remove nitrogen and organics from young landfill leachate. However, with the extension of landfill time, refractory compounds such as humic acids and fulvic acids make biological processes inefficient [35]. Advanced oxidation processes (AOPs) can effectively compensate for the limitations of physical and biological methods, and are often used to treat refractory organics. However, their high economic cost remain a challenge [36]. The treatment of leachate depends on its characteristics and age, as well as factors such as the required capital investment, operational costs, and the desired level of pollutant removal.