## 2 Application of Membranes in Contamination Situations
### Surface Water Contamination
These polymers exhibit excellent permeability, selectivity, and stability (chemical, mechanical, and thermal) and are therefore used in water treatment. PSF and PES are mainly used as membrane materials used in UF, NF and RO [28]. In recent years, research on the improvement of membranes has focused on introducing nanomaterials into the structure of the membrane. Advanced nanocomposite membranes can be designed to use the synergy effect of the polymer matrix and the introduced nanomaterial, which allows meeting the requirements for specific applications in removing contaminants from water [29]. The ion exchange membranes used in electrodialysis processes are very similar to conventional ion exchange resins also in terms of their chemical structure. They are characterized by high selectivity and low resistivity. Such membranes are most often obtained by introducing anionic or cationic groups, respectively, into a pre-formed solid foil, such as a membrane based on styrene-DVB or polysulfone, and then dissolving the modified polymer and, from the solution thus obtained, casting a film forming the membrane [30]. The selection of the appropriate membrane and water purification techniques allows obtaining the desired results. The use of membranes in the treatment of water sources containing anionic micropollutants is most commonly used with RO using filter membranes or ED, especially when separation into monovalent and polyvalent anions is desired. In the case of using NF membranes, it is a consequence of both the size of the ions and the charge exclusion effects, while in ED it is due to the use of ion exchange membranes permeable to monovalent anions [31]. The combination of the advantages of membrane separation with biological reactions in the treatment of surface waters has led to the development of three main types of membrane bioreactors: pressure-differential membrane bioreactors, biological membrane Contactors, and pressure-driven membrane bioreactors, biological membrane Contactors, and ion exchange membrane bioreactors [32]. Another example of a novel water treatment system is the use of biopolymer-based membranes to remove herbicides from contaminated surface waters. The use of biopolymer membranes with natural polymers (chitosan and alginate) for the removal of widely used herbicides, such as Diquat (DQ), Difenzoquat (DF), and Clomazone (CLO), was investigated [33]. It was found that the alginate-based membranes showed good DQ and DF absorption, mainly due to the possibility of Coulombic interactions between the alginate carboxyl groups and the positive charges of these herbicides. The key determinants of the membrane adsorption capacity are the dissociation constants and the herbicide partition coefficients since higher dissociation constants and lower partition coefficients resulted in higher adsorption. Chitosan/alginate hybrid membranes with a layered structure did not show the best result. However, this type of membrane may be of interest in the context of the adsorption of different herbicides in the various layers of the membrane, e.g., a positively charged herbicide may be adsorbed onto an alginate layer and a negatively charged herbicide may simultaneously be adsorbed into the chitosan layer while being a very effective adsorbent for DQ. Moreover, the pH value of contaminated water may be an important parameter determining the adsorption behavior of the tested herbicides. Another source of surface water and wastewater contamination can be industrial processes related to metal coating, which is one of the most widely used surface finishing techniques for various parts of the devices. In this process, the surface is coated with the deposition of certain metals, and the process itself is one of the most dangerous industries due to the production of a large amounts of waste chemicals.