Membrane technologies play a pivotal role in various industrial sectors, including food processing. Membranes act as barriers, selectively allowing the passage of one or other types of species. The separation processes that involve them offer advantages such as continuity, energy efficiency, compactness of devices, operational simplicity, and minimal consumption of chemical reagents. The efficiency of membrane separation depends on various factors, such as morphology, composition, and process parameters. Fouling, a significant limitation in membrane processes, leads to a decline in performance over time. Anti-fouling strategies involve adjustments to process parameters or direct modifications to the membrane, aiming to enhance efficiency. Recent research has focused on mitigating fouling, particularly in the food industry, where complex organic streams pose challenges. Membrane processes address consumer demands for natural and healthy products, contributing to new formulations with antioxidant properties. These trends align with environmental concerns, emphasizing sustainable practices. Despite numerous works on membrane modification, a research gap exists, especially with regard to the application of modified membranes in the food industry. This review aims to systematize information on modified membranes, providing insights into their practical application. This comprehensive overview covers membrane modification methods, fouling mechanisms, and distinct applications in the food sector. This study highlights the potential of modified membranes for specific tasks in the food industry and encourages further research in this promising field.

3D-printing enables the fabrication of membranes with desired shapes and geometrical parameters. In this study, a membrane for pressure-driven processes was manufactured in a single step using the fused deposition modeling (FDM) technique. The membrane was produced from a mixture of polylactic acid (PLA) with sucrose as a pore-forming agent. Sucrose was removed from the final membrane by washing it with water. The membrane consists of three layers, and this sandwich-like structure ensures its mechanical stability. The material obtained was characterized using SEM and AFM imaging, as well as nitrogen adsorption-desorption and contact angle measurements. The porosity of each layer of the membrane is due to a loose region, which is coated on both sides with a dense film formed during printing. The pores responsible for rejection capability can be found in grooves between the polymer stripes in the dense layer. The membrane exhibits a water permeability of 64 L m⁻²h⁻¹bar⁻¹, with a molecular weight cut-off of 69 kDa. The PLA membrane can be used for polyphenol concentration, demonstrating a permeability of 2–3.4 L m⁻²h⁻¹bar⁻¹ and a selectivity towards these compounds of 78–98% at 0.5 bar, with a flux decline ratio of up to 50%.

The work solves the problem of obtaining adsorbents from cheap and available feedstock able for the removal of low-molecular-weight toxic organic substances from aqueous solutions. It is proposed to obtain an adsorbent from the wastes of such biodegradable poly­mer as polylactic acid (PLA), for example, from used packaging. The polymer was heated up to the melting point, cooled and ground. The thermally treated PLA sample contained end carboxyl and hydroxyl groups, which were identified with Fourier-IR spectroscopy, and the ion-exchange activity of the polymer was found. These groups provide a surface charge density of 0.02−0.12 C m-2 in the pH range of 4−10, ξ-potential reaches 30 mV in an alkaline media. Adsorption of such cationic dye as methylene blue (MB) was studied under static and dynamic conditions. The Temkin and Freundlich models were applied to the adsorption isotherms, an increase in the adsorption capacity of the polymer was found with an increase in pH from 4 to 10, while the surface became more energetically heterogeneous. The capacity of PLA is 16−30 mg g-1 in the absence of a supporting electrolyte, and 10−28 mg g-1, when adsorption occurs from a two-component solution containing also NaCl. According to the results of the study of MB adsorption, and the data of electronic spectroscopy for suspension of the polymer, it was established that the dye removal from the solution occurs mainly due to electrostatic attraction to the negatively charged PLA surface. The adsorbent was proposed to be employed for the remo­val of the residual colour of wastewater after its treatment, for example, with reverse osmosis or nanofiltration.

Adsorption is a promising solution to the presence of contaminants in water resources that involves the use of adsorbent materials, such as granular activated carbon (GAC) and nanoparticles like silver (Ag) and copper (Cu). However, the practical challenge of using pure GAC lies in its susceptibility to biofouling. This study aimed to develop a multifunctional GAC/AgCu nanocomposite to address the dual challenge of pharmaceutical contamination and bacterial activity of Escherichia coli. Characterization by SEM, XRF, XRD and FTIR confirmed the successful impregnation of nanoparticles. Kinetic studies showed that the pseudo-first-order model was more suitable for both caffeine and paracetamol contaminants. The Langmuir model provided the best fit for isotherms, achieving maximum adsorption capacities of 138.35 $\mathrm{m}\mathrm{g} {\mathrm{g}}^{-1}$ for caffeine and 92.21 $\mathrm{m}\mathrm{g} {\mathrm{g}}^{-1}$ for paracetamol. In antibacterial tests, GAC/AgCu achieved a bacterial reduction of over 97%, whereas pure GAC showed no inhibitory effect, confirming that the antimicrobial properties are derived from the Ag and Cu nanoparticles. These results highlight GAC/AgCu as a promising multifunctional material for the simultaneous removal of emerging pharmaceutical pollutants and biological contaminants, offering a solution to mitigate biofouling and enhance water treatment efficiency.

3D printing allows one the production of membranes of any shape and size according to consumer requirements. The work solves the problem of studying the separation properties of filtration membranes, which, unlike the known ones, were obtained via one stage. Polylactic acid (polylactide, PLA) and its mixture with a pore former − sucrose served as the ink for the 3D printer. The fused deposition mo­delling technique was used for printing. The membranes imcluded three layers, and each layer consisted of parallel strips, the width of which was determined by the diameter of the extruder nozzle (0.4 mm). The pores that provide filtration can be located at the joints of the strips. The membranes almost completely retain bovine serum albumin (BSA) macromolecules. The pore size is estimated to be 6−17 nm, in other words, the membranes show ultrafilt­ration properties. The membranes were used to concentrate polyphenols from an extract of orange peels and to recovery cationic and anio­nic dyes (methylene blue and reactive black 5, respectively) from aqueous solutions. It was found that the highest selectivity of the membranes is realized at a pressure of 0.5 (polyphenols, 90−98%), 1.5 (anionic dye, 90−96%) and 2.5 bar (cationic dye, 83−87%). Filtration leads to decolorization of weakly colored solutions. It was found that the membrane obtained from a mixture of PLA and a pore former is characterized by higher productivity, selectivity, and resistance against organic contaminants than a membrane made of pure polymer. It is assumed that the difference between the behaviour of the membranes is due to the peculiarities of the thermal destruction of PLA during printing, which occurs at 200