## 1 Introduction  
Environmental contamination has indeed been recognized as a significant challenge confronted by human beings since the 20 th century, and it continues to be a pressing issue today. Pollution is defined as the introduction of contaminants or detrimental substances into the environment, which can cause harmful impacts to human health, living organisms, and even ecosystems. In the case of water pollution, these negative effects are further intensified by the growing demand for water from citizens, agriculture, and industries [1, 2]. In recent decades, organic substances have been detected, due to the continuous development of analytical techniques, with increasing frequency in concentrations ranging from ng/L to ug/L in groundwater, urban wastewater, surface water, and drinking water [3]. These substances are known by various names, the most used and recognized being \"emerging contaminants\". This class of compounds is defined as chemicals of synthetic or natural origin or microorganisms that are not commonly monitored in the environment but that may have adverse effects on the environment or human health [4]. This category includes pharmaceutical and personal care products, pesticides, heavy metals, and industrial chemicals [5]. Additionally, pathogens, including bacteria, viruses, protozoa, and parasites, represent a major concern for water pollution, as these microorganisms can cause serious diseases and even death [6]. The spread of antibiotic-resistant bacteria through contaminated water sources further complicates public health efforts, since these can be transmittedto humans, particularly affecting those with chronic conditions [7]. Additionally, these compounds disrupt ecological balances, affecting the development and reproduction of aquatic species [8]. To confront the problem, diverse technologies have been developed. Among them, advanced oxidation processes (AOPs) have become increasingly important in addressing the challenges of water pollution. Their ability to degrade recalcitrant pollutants such as drugs and personal hygiene products [9], organic micropollutants [10], and pesticides [11] and provide environmental protection make them a valuable tool in modern wastewater treatment strategies. Among the various AOPs, peroxymonosulfate (PMS)-based AOPs have received intensifying attention for environmental remediation by reason of the powerful generation of hydroxyl radical (\(H\)O\({}^{\bullet}\), standard potential = 2.0-2.8 V versus standard hydrogen electrode vs. NHE), sulfate radical (\(SO_{4}^{\bullet-}\) 2.5-3.1 V vs. NHE), or singlet oxygen (\({}^{1}\)O\({}_{2}\), 2.2 V vs. NHE) [12; 13]. In fact, PMS might be activated through different methods such as thermal activation [14], ultraviolet light (UV) activation [15], photocatalysis [16], electrochemical methods [17], ultrasound irradiation [18], and transition metals [19; 20; 21]. Among the previously highlighted activation methods, the use of transition metal-derived catalysts for PMS activation has been recognized as a promising advanced oxidation technique with significant potential for organic decontamination. These catalysts are based on, or derived from, transition metals located in the d-block of the periodic table, such as iron (Fe), copper (Cu), cobalt (Co), and nickel (Ni), among others. They are known for their unique catalytic properties, including multiple oxidation states and the ability to form complexes with various ligands. Additionally, they exhibit robust catalytic activity, offer potential for reuse through recycling, and are cost-effective. Moreover, among the transition metals, Cu has been considered particularly effective in activating PMS [22] due to several compelling reasons that give it an advantage over Fe, which is also commonly used in such processes. One of the key advantages of Cu over Fe is its ability to operate effectively over a wider pH range.