## 1 Introduction  
The demographic growth in developed countries and consequently, the demand for products from agriculture, livestock and industry has increased and led to a significant development of the related industries [1]. However, despite the magnificent benefits provided to society, there is evidence that soil, water and atmosphere are still being polluted [2]. Among these major environmental problems, the water environment is of particular importance because it is a valuable and limited resource [3]. Further, the wastewater treatment plants (WWTP) of today are not capable of degrading or removing persistent organic pollutants from wastewater. These organic pollutants, including the newly recognized emerging persistent organic pollutants, have increasingly been detected in recent years [4]. This term typically refers to substances that have been introduced to the environment or that have been discovered in nature, whether they are synthetic or natural. Persistent organic pollutants are generated from compounds applied for a range of purposes including pharmaceuticals and personal care products, pesticides, food additives and dyes from the textile industry [4]. Therefore, as this problem instead of diminishing has had the opposite effect, efforts to develop new and more efficient and environmentally sustainable technologies are urgently needed. Of all the recent technologies developed up-to-date, Advanced Oxidation Processes (AOPs) are the most efficient in removing these persistent organic pollutants from aqueous media and are considered eco-friendly treatment processes. These helpful processes are based on the in situ production of non-selective radicals with a strong oxidation power able to mineralize the organic pollutants. Among the mentioned radicals, hydroxyl (HO\({}^{\bullet}\)), sulphate (SO\({}_{4}^{\bullet-}\)) and superoxide (O\({}_{2}^{\bullet-}\)) radicals are the most used since they give the highest oxidative capacity and have better environmental properties [5]. Producing these radicals is a complex process that requires a catalyst for their generation by different activation methods. Moreover, to improve the AOPs, alternative catalysts to the conventional ones are required. Among the different alternatives, metal-organic frameworks (MOFs) have arisen as suitable options since they are of great interest for their use in wastewater treatment. The first time that a MOF was used as a heterogeneous catalyst in an oxidation process was reported by [PERSON] et al. [6]. They developed an efficient heterogeneous catalytic pre-treatment of Olive oil mill wastewaters (OOMW) in which the biodegradability of the OOMW was increased to make possible the subsequent biological oxidation. The used MOF contained copper, Cu\({}_{3}\)(BTC)\({}_{2}\)(H\({}_{2}\)O)\({}_{3}\) (BTC = benzene 1,3,5-tricarboxylic acid), showing a high micropore volume, large pore sizes, crystallinity, and a high metal content. In comparison to the homogeneous catalyst, this material provided good properties to significantly improve the biodegradability of the OOMW and opened the possibility to recover the catalyst and reuse it. These results clearly revealed the great potentialities of MOFs as a catalyst that have attracted much attention for exploiting new applications of MOFs in wastewater treatment. However, they have the great disadvantage that many of them are not stable in water. Besides this, it is also important to keep in mind that, as with any synthesis, a high level of purity is reached, but they always contain impurities or do not have the desired morphology [7]. Therefore, in recent years, one of the main aims of MOF synthesis has been the development of alternatives to conventional methods to improve production yields and control their morphology [7]. The main goal of this work is to highlight recent progress in applying MOF derivatives as emerging efficient heterogeneous catalysts for the removal of organic persistent pollutants by different AOPs.