on activated alumina [19]. Nevertheless, there is still a need to develop special treatment systems for arsenic removal at the household level that will not require frequent manual intervention or the use of chemicals for trivalent arsenic (As(III)) pre-oxidation; in the usual treatment methods, As(III) cannot be removed efficiently from water. This is due to the fact that As(III), when in an environment with pH values relevant to drinking water treatment, is present in its non-ionic form of arsenious acid, whereas pentavalent arsenic (As(V)) is present in its oxyanionic species, H\({}_{2}\)AsO\({}_{4}\)\({}^{-}\) or HAsO\({}_{4}\)\({}^{2-}\). Conventional treatments for arsenic removal include coagulation-flocculation using iron and aluminium-based salts [17], adsorption onto iron oxides [20] or activated alumina [21], ion exchange [22], membrane processes [23] (mainly nanofiltration) and reverse osmosis [24]. Almost all these processes are very efficient for removing the pentavalent arsenic form but, in the case of trivalent arsenic, there is a need for a peroxidation step to oxidize As(III) into As(V). A growing body of research [14; 15; 25] is, therefore, developing materials and technologies that can remove both As(V) and As(III) equally efficiently.  
The oxidation of As(III) is primarily accomplished using chemical oxidants, such as KMnO\({}_{4}\)[26], NaOCl, manganese oxides [26], or ozone [27; 28]. These oxidants are very efficient for the oxidation of As(III) but might cause several secondary complications, which occur mostly from the presence of residuals or from the formation of side products, also inducing a substantial augmentation of the respective operational costs.  
To overcome these problems and limitations, several methods have been developed that can remove arsenic without the use of oxidants for the transformation of As(III) [29; 30], such as the use of biological oxidation or the use of specifically designed adsorbents that have a dual action, i.e., oxidizing As(III) and adsorbing the formed As(V), such as with the use of tetravalent manganese ferroxytte or the use of zero-valent iron [31] under oxidic conditions.  
In this regard, several researchers have used specifically modified molecularly imprinted polymers for removing both As(III) or As(V) [32], depending on the type of imprinted template. In this way, they showed that this technique could efficiently remove either As(III) or As(V), or even mixtures of both species, as they normally exist in natural water sources. Furthermore, some researchers have used advanced modifications of MIPs by incorporating iron oxides into their structure [32] to improve the sorptive efficiencies of the new materials. The latter developments have rendered the use of MIPs a very promising technology for applications in water treatment and especially for arsenic removal from groundwaters or other water sources, such as rivers or lakes [33]. The importance of the use of MIPs for the removal of arsenic from groundwaters is that these materials are very selective toward the contaminant of interest. This superior selectivity is ascribed to the function of specific templates incorporated in the materials that can adsorb the contaminant of interest, i.e., arsenic, almost exclusively. Therefore, the main problem in these adsorption processes is the competition for adsorption sites by other water components, for example, phosphates, nitrates, carbonates, and sulfates, which is circumvented by the use of MIP-type adsorbents.  
In the present review article, those studies that have used MIPs for arsenic removal are reviewed in detail, as well as mentioning several applied modifications, i.e., the type of monomer, cross-linker, and template. The mechanism and efficiency of removal for both arsenic species are highlighted. To the best of our knowledge, this is the first review appearing in the literature describing the use of MIPs for arsenic removal from water.