In this study, we explore the possibility of reusing end-of-life seawater reverse osmosis (RO) membranes to treat brackish water and industrial effluent. Prior to cleaning the end-of-life RO membranes, we conducted several autopsies in order to assess the extent of degradation. Based on these results, three cleaning protocols were tested and Ultrasil10 and/or chlorine solution were selected for further investigation. The cleaning capacity of the chlorine treatment at 4000 ppm.h was tested but proved inefficient as it leads to a denser cake and a significant decrease in hydraulic permeability. Therefore, we recommend commencing chemical cleaning with Ultrasil10 to remove foulants, thereby reconditioning the end-of-life RO membranes to meet nanofiltration membrane specifications. The cleaned end-of-life RO membranes exhibited enhanced hydraulic permeability (1.97 L·h⁻¹·m⁻²·bar⁻¹) and achieved a salt rejection of 85% for brackish water (6 g/L NaCl). With a molecular weight cutoff of 86 Da, these membranes effectively reduced brackish water conductivity to below 1000 µS/cm at 10 bars, complying with Tunisian drinking water standards (300–2500 µS/cm). Additionally, they demonstrated high efficiency in treating industrial effluents, achieving turbidity levels below 2 NTU and conductivity of 180 µS/cm. Operating at lower pressures, these membranes provided cost-effective, sustainable solutions and performed comparably to commercial new NF membranes, validating their potential for reuse in brackish water and wastewater treatment applications.

As sensitive parts of the water treatment process, reverse osmosis (RO) membranes are the most important for desalination and wastewater treatment. But the performance of RO membranes deteriorates over time due to fouling, necessitating frequent replacements. One of the environmental challenges is the disposal of End-of-Life (EoL) RO membranes, which are made of non-biodegradable polymers. The reuse of EoL membranes as a sustainable approach for waste saving and resource efficiency has recently attracted considerable attention. The present work provides a comprehensive overview of the strategies for reusing EoL RO membranes as sustainable alternatives to conventional disposal methods. Furthermore, the fundamental principles of RO technology, the primary types and impacts of membrane fouling, and advanced cleaning and regeneration techniques are discussed. The conversion of EoL membranes into nanofiltration (NF), ultrafiltration (UF), and forward osmosis (FO) membranes is also covered in this review, as well as their uses in brackish water desalination, dye/salt separation, groundwater treatment, and household wastewater reuse. Environmental and economic benefits, as well as technical, social, and regulatory challenges, are also discussed. Finally, the review highlights innovative approaches and future directions for incorporating EoL membrane reuse into circular economy models, outlining its potential to improve sustainability and reduce operational costs in water treatment systems.

The purpose of the present study is to investigate the extraction of lithium from southern Tunisian brines. Density and concentration of Lithium in those brines were reported. Also, pondered rates of Lithium and the major elements in brines were investigated. Obtained results indicate that Lithium exist in those brines as traces. The optimization of certain parameters is required in this study. To extract Lithium from natural brines two steps were investigated. Firstly, we have used Ammonium Oxalate ((NH₄)₂(C₂O₄)⋅2H₂O) to precipitate only Magnesium ion: in this procedure, three parameters were investigated (Mg/Oxalate, T (°C) and t_stirring). The maximum values were found to be Mg/Ox = 0.66, T = T_reflux = 100°C and t_stirring ≥ 30 min. Secondly, we have used Aluminum Chloride (AlCl₃⋅6H₂O) in order to adsorbing lithium ions by Aluminum hydroxide. In this procedure, four parameters were investigated (pH, Al/Li, t_stirring and T (°C)). Maximum values of these parameters are 7.2, 4.7, 3 h and 25°C respectively. Finally, to separate Lithium from Aluminum solution, we have used an exchange ion resin. This solution including two ions under cationic form (Al³⁺ and Li⁺). Al³⁺ was complexed into [Al(C₂O₄)₃]^3– using Ammonium Oxalate ions (\({{{\text{C}}}_{{\text{2}}}}{\text{O}}_{4}^{{2 - }}\)) and removed from solution using an anion exchange resin (Amberlite IRA-402). Thus, a theoretical study was carried out to determine the appropriate pH for separation. After Aluminum ions complexation by ammonium oxalate, Ox/Al molar ratio and pH was studied. Optimal values of these parameters are 3 and 4 respectively and the recovery of Li⁺ is set to be 98.5%.

The objective of this study is to evaluate the degradation of end-of-life BWRO membranes sourced from a factory in France by analyzing their water permeability, roughness, and chemical composition in order to diagnose the level of degradation incurred during their first life cycle in water softening. Following this, two new applications for the end-of-life BWRO membranes were investigated: (i) as ultrafiltration membranes (UF) for domestic effluent treatment and (ii) as cation exchange membranes (CEM) for use in fungal microbial fuel cells (FMFC). The UF membrane was renovated with an acetic acid treatment and, subsequently, used for domestic effluent filtration. The cation exchange membrane was developed in two steps: (i) chlorine treatment and (ii) the deposition of an Amer Sil layer, a functional coating formed by an interpenetrating polymer network (IPN) made of sulfonated polyether sulfone (S-PES) in a cross-linked matrix of acrylic acid and divinylbenzene.

We have investigated the use of chitosan for aluminium removing from (Li⁺–Al³⁺) aqueous solutions. The isotherms and kinetics of adsorption with respect of initial aluminium concentration and pH were investigated. The optimum pH value for quantitative adsorption is 4. Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms. Three simplified kinetics models, based on first-order, pseudo second-order and Elovich equations, were tested to describe the adsorption mechanism.