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The shortage of clean water sources and increase of demand for fresh water have become as major global challenges not only in industries but also inhuman life. Meanwhile, membrane technology has been extensively noticed due to high separation efficiency, energy-saving and environmentally-friendly characteristic. So, development of new membrane is a vital step in advancing of membrane application in water-treatment. This paper presents a comprehensive review on development of high-performance nanofiltration membrane based on nanotechnology for wastewater treatment. Application of new nanomaterials has enabled fabrication of NF-membranes with improved separation properties for pollutants removal from water. Recognizing that conventional membranes are not necessarily suitable for industrial applications and/or process intensifications many attempts were made recently to use of nanomaterials into NF-membranes, aiming to overcome trade-off relationship between flux/selectivity and to improve their stability. So, development of new structured nanomaterial with desirable properties is one of most crucial research topics for membrane researchers. Accordingly, an overview on different methods to design of advanced nanomaterial presented that allow us to overcome their inherent problems in membranes fabrication such as agglomeration, defects formation, insufficient pores’ tuning, poor active sites and anti-fouling properties; however, selection of appropriate nanomaterials is a challenge of utmost difficulty. Various types of nanomaterials such as zeolites, carbon based, framework (MOF/ZIF/COF), nano-biopolymers and special nanoparticles such as SFNPs, SFNCs, POSS, ZCPs, and nickel hydroxide nanosheet are presented and their roles in NF-transport are discussed as well as strategies for surface modification of nanoparticles to promoting their surface charges density. Moreover, fabrication methods of nano enhanced NF-membranes including layer by layer assembly, hollow fiber spinning, electrospinning of nanofibers, construction of thin-film nanocomposite besides blending, co-polymerization; cross-linking and grafting techniques are discussed. A proper view for selection of appropriate nanoparticles in membrane fabrication is offered while considering types of pollutants to be removed.

Environmental protection and climate change are current issues at the heart of global economic growth. The awareness of the real risks connected with industrial membrane production sector has been the push towards the search of new, more sustainable, sol vents and raw materials . In this context, dihydrolevoglucosenone (Cyrene(TM)) comes as a green biosolvent derived from waste cellulose, with enormous potentiality, which could offer the possibility to re-design manufacturing processes from the origin. The increasing interest devoted to Cyrene(TM) has its basis in the similarity with many physi cal-chemical properties of highly toxic organic solvents normally used for fabrication membranes (such as N-Methyl-2-pyrrolidone, N,N-Dimethylformamide and N,N-dimethy l acetamide). In fact, Cyrene(TM) is presented as a polar aprotic organic solvent, comple tely miscible with water, and with a relatively high boiling point (227 °C). Herein, Cyrene(TM) was employed for the preparation of polyethersulfone (PES) and pol y(vinylidene fluoride) (PVDF) membranes via phase inversion [2]. By preparing PES/C yrene(TM) and PVDF/Cyrene(TM) casting solutions, without the use of any additive, and b y working at room temperature, microfiltration and ultrafiltration membranes were obta ined. Non-solvent induced phase separation (NIPS) and its combination with vapour-in duced phase separation (VIPS) were adopted as preparation procedure. PES and PVDF membranes were characterized in terms of thickness, porosity, pore size, contact angl e and pure water permeability. The morphology was also assessed. For PVDF membra nes, additional differential scanning calorimetry and Fourier transform infrared spectros copy analysis were performed. The obtained results evidenced as, by varying the exposure time to controlled humid a ir and temperature during the VIPS-NIPS process, membranes with different morpholo gy and properties can be prepared, demonstrating the applicability of Cyrene(TM) for a more sustainable membrane fabrication.

Membrane capacitive deionization (MCDI) has shown many advances, however, its performance in combination with other treatment technologies has not been widely reported. In this study, a pilot-scale low-pressure reverse osmosis (LPRO) (FilmTec™ XLE-2540) with MCDI (CapDI© C17, Voltea) was developed and tested as a promising modular desalination system. The systems were evaluated individually at different salinities and tested together as a modular system. The study focused in the comparison to conventional seawater reverse osmosis (SWRO) (FilmTec™ SW30-2540) at pilot-scale and in theory using the software Water Application Value Engine (WAVE, DuPont™), including a cost evaluation of the systems. Pilot tests were carried out in Can Gio, a riverine estuary region in South Vietnam, which is affected by progressive salinization (TDS ≈ 1–25 g/L). Drinking water quality (TDS < 600 mg/L) was achieved with a specific energy consumption (SEC) of 5.2 kWh/m³. Additionally, fouling mitigation was investigated for the ultrafiltration (UF) pre-treatment by periodic hydraulic and chemical enhanced backwashing. While the SWRO had a slightly lower SEC of 5.0 kWh/m³, WAVE calculations showed that lowering the SEC to 3.6 kWh/m³ is possible by improving the LPRO pump design and an optimization of the MCDI operation. Post-print / Final draft

Graphene oxide (GO)-polyimide mixed matrix membranes (MMMs) were produced using chloroform by solvent evaporation. These membranes have been used, for the first time, in pervaporation (PV) for the separation of azeotropic methanol (MeOH)- methyl tert-butyl ether (MTBE) mixtures (14.3 and 85.7%, respectively). The effect of GO loading in the PV process was investigated. The PV experiments were carried out at different feed operating temperatures (25–45 °C). Furthermore, an analysis of the PV process through the Arrhenius relationship has been given. The feed temperature (in the range of 25–45 °C) affected the permeation of both components producing an increase in total permeate flux; however, separation factor was compromised. Indeed, the best permeate fluxes (ca. 0.091 kg m−2 h−1) of the MMMs (4 wt% GO) were found at 45 °C, while the best separation factor (α = 28) was found at 1 wt% GO at 25 °C. In addition, the membranes were characterized by TGA, SEM, DSC, solvent uptake and mechanical test (Young’s modulus). Finally, the performance of the GO-polyimide membranes was compared with other polymeric and MMMs membranes at the azeotropic conditions., R. Castro-Muñoz acknowledges the European Commission - Education, Audiovisual and Culture Executive Agency (EACEA) for his PhD scholarship under the program: Erasmus Mundus Doctorate in Membrane Engineering – EUDIME (FPA No 2011-0014, Edition V, http:/eudime.unical.it). This work was partially supported by the Operational Program Prague – Competitiveness (CZ.2.16/3.1.00/24501) and the “National Program of Sustainability“ (NPU I LO1613) MSMT-43760/2015. Financial support from the Spanish MINECO and FEDER (MAT2016-77290-R), the Aragón Government (T43-17R) and the ESF is also gratefully acknowledged.

In this work, for the first time, porous Matrimid® 5218 membranes were prepared by employing a combination of vapour induced phase separation (VIPS) and non-solvent induced phase separation (NIPS) technique. N-methyl-2-pyrrolidone (NMP) and Rhodiasolv® Polarclean were used as a traditional and new green solvent, respectively, for the preparation of the membranes. Ternary phase diagrams with both solvents were preliminary carried out. The exposure time to humidity and the effect of polymer concentration on membrane morphology and properties were evaluated. The resulting membranes were fully characterized in terms of morphology, shrinkage propensity, thickness, porosity, mechanical properties, pore size, contact angle and water permeability.

The presence of arsenic in water beyond the admitted limits is becoming an important concern for many Countries. Methods usually employed for the arsenic removal from water are based on coagulation followed by filtration, ion-exchange, adsorption. Drawbacks like the use of chemicals and the production of sludges (in case of coagulation) have, however, to be mentioned. Membrane operations, based on the features of membrane materials involved in the separation, do not need chemicals and are easy to scale-up, due to their modularity. In this contribution, the potential of membrane operations for the treatment of arsenic-polluted water is presented and discussed. In particular, two classes of membrane operations are illustrated and compared, the pressure-driven, like Nanofiltration (NF) and Reverse Osmosis (RO) and the thermally-driven ones, like Membrane Distillation (MD).

Crystalline aquifers are layered systems in which the hydrogeological path of waters extends from highly weathered, shallow and porous rocks to poorly weathered, deep and fissured rocks. This varying hydrogeological setting influences the water chemistry in different ways. The paper aims to reconstruct the water-rock interaction process in these various environments starting from a solid reactant represented by an average granite rock and several waters from the shallow aquifer. Afterwards, the water-rock interaction processes occurring in the deep environment are reconstructed, varying the geochemical conditions (primary reactants, secondary mineral phases allowed to precipitate, fO2 and fCO2), with a special focus on fluoride (F-). The evolution from the F-poor, Ca-HCO3 facies to the F-rich, Na-HCO3 water type of high pH was simulated using reaction path modelling.

Deep eutectic solvents (DESs) and natural deep eutectic solvents (NADESs, derived from natural-source molecules) were used for the first time in the preparation of porous poly(vinylidene fluoride) (PVDF) and poly(acrylonitrile) (PAN) membranes. Halogen-free Brønsted acidic DES and zwitterionic carboxy- and sulfo-betaines DESs and NADESs were selected for their potentiality to solubilize the chosen polymers. Solubility prediction was assessed through the analyses of the solvents' thermodynamic factors and the calculation of the relative solubilities in terms of relative energy difference and Hansen and Hildebrand parameters. Porous membranes were, thus, prepared via phase separation technique adding to the dope solutions different non-toxic co-solvents (Rhodiasolv® PolarClean, triethyl phosphate and dimethysulfoxide) with the aim of reducing solution viscosity. The effect of different coagulation bath compositions, such as water and water/isopropanol, was investigated in order to control and tailor the morphology and architecture of the produced membranes. The pore dimensions and distribution, porosity, contact angle and water permeability tests were carried out in order to characterize the produced membranes. The results of the study showed the potentiality of DESs and NADESs to be employed as solvents for the preparation of more sustainable polymeric membranes for water treatment applications.

Deep eutectic solvents (DESs) are a new class of solvents that can offset some of the major drawbacks of common solvents and ionic liquids. When dealing with the preparation of dense membranes, the use of DESs is still challenging due to their low compatibility with the polymer phase. In this research, a novel L-proline:sulfolane (molar ratio 1:2) DES was synthesized and used for the preparation of more sustainable bio-based membranes using chitosan (CS) as a polymer phase. The compatibility among both phases (polymer and DESs) and their ability to form homogenous membranes was preliminary studied. In this regard, scanning electron and confocal microscopies were used to completely map the structure of the resulting membranes evidencing a complete homogenous structure. The membranes were also characterized in terms of contact angle (CA), Fourier transformed infrared spectroscopy (FTIR), mechanical resistance and swelling degree (uptake). Preliminary pervaporation tests for the separation of a methanol (MeOH)- methyl tert-butyl ether (MTBE) azeotropic mixture were, thus, performed. In this regard, the addition of DESs provided an enhanced separation efficiency in comparison to pristine CS membranes. Thanks to the morphology and properties exhibited, the newly developed membranes can be considered as excellent bio-based candidates to be explored in other gas selective and solvent oriented membrane operations.

Matrimid®5218 dense membranes were produced using NMP by solvent evaporation. The membranes have been used, for the first time, in pervaporation (PV) separation of azeotropic methanol (MeOH)- methyl tert-butyl ether (MTBE) mixtures (14.3 and 85.7 wt%, respectively). The membranes were characterized by TGA, SEM, DSC, contact angle and swelling tests. The PV experiments were carried out at different feed temperatures (25–45 °C) and vacuum pressures (0.0538, 0.2400, 2.1000 mbar). Moreover, an analysis of the PV process through the Arrhenius relationship has been provided. The feed temperature (in the range of 25–45 °C) affected mainly the MeOH permeation producing an increasing on its partial permeate flux and separation factor as well. Indeed, the best performances of Matrimid® were found at 45 °C and 0.054 mbar, where a permeate flux and a separation factor of about 0.073 kg m−2 h−1 and 21.16, respectively, were obtained. Finally, the Matrimid PV performance was compared with other polymeric membranes at the azeotropic conditions.