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A composite cellulose acetate (CA) carbon-based aluminium hydroxide (CACG) hydrogel membrane was prepared for water purification and real leachate wastewater treatment. The composite CACG hydrogel structure was characterized using scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Initially, the study investigated the efficiency of the composite CACG hydrogel membrane in removing divalent ions such as Cu2+, Pb2+, Mg2+, and Ca2+ at 10 mg/L and 1000 mg/L concentrations from synthetic feed solutions. The results revealed that metal ions removal efficiency was higher at 10 mg/L feed concentration. The composite CACG hydrogel membrane demonstrated high selectivity for Cu2+ and Pb2+ ions, with more than 99% removal from the solution. The performance of the CACG hydrogel was evaluated in four cycles with a constant metal ions removal efficiency of over 98%. These findings suggest composite hydrogel could be a promising adsorbent material for removing metal ions from synthetic water and wastewater. The total suspended solids (TDS) were reduced by 58%. Additionally, the concentrations of arsenic (As3+), lead (Pb2+), zinc (Zn2+), copper (Cu2+), nickel (Ni2+), Manganese (Mn2+), Magnesium (Mg2+), Potassium (K+), Calcium (Ca2+), and Sodium (Na+) saw reductions of 99.9%, 98.3%, 96%, 96%, 99.6%, 93%, 74.75%, 73.6, 60%, and 14.9% respectively. [Display omitted] • CA/AC-aluminium hydroxide hydrogel was prepared and characterized for wastewater treatment. • The hydrogel pure water flux was 30 L/m2h and heavy metals rejection was between 95% and 99%. • The hydrogel rejection of copper was constant at 99% in 4 consecutive filtration cycles. • The order of ions removal was found to be As3+ > Ni2+ > Pb2+ > Zn2+ > Cu2+ > Mn2+> Mg2+ > K+ > Ca2+ > Na+. [ABSTRACT FROM AUTHOR]

To meet the rising global demand for water, it is necessary to develop membranes capable of efficiently purifying contaminated water sources. Herein, we report a series of novel polysulfone (PSf)/GO-vanillin nanofiltration membranes highly permeable, selective, and fouling resistant. The membranes are composed of two-dimensional (2D) graphite oxide (GO) layers embedded with vanillin as porogen and PSf as the base polymer. There is a growing interest in addressing the synergistic effect of GO and vanillin on improving the permeability and antifouling characteristics of membranes. Various spectroscopic and microscopic techniques were used to perform detailed physicochemical and morphological analyses. The optimized PSf 16 /GO 0.15 -vanillin 0.8 membrane demonstrated 92.5% and 25.4% rejection rate for 2000 ppm magnesium sulphate (MgSO 4) and sodium chloride (NaCl) solutions respectively. Antifouling results showed over 99% rejection for BSA and 93.57% flux recovery ratio (FRR). Experimental work evaluated the antifouling characteristics of prepared membranes to treat landfill leachate wastewater. The results showed 84–90% rejection for magnesium (Mg+2) and calcium (Ca+2) with 90.32 FRR. The study experimentally demonstrated that adding GO and vanillin to the polymeric matrix significantly improves fouling resistance and membrane performance. Future research will focus on molecular sieving for industrial separations and other niche applications using mixed matrix membranes. [Display omitted] • PSf/GO-vanillin antifouling membrane was fabricated for landfill wastewater treatment. • Pure water flux of PSf/GO-vanillin membrane is 3 times higher than that of PSf-vanillin membrane. • The rejection rate of Mg+2 and Ca+2 by the PSf/GO-vanillin membrane is between 84% and 90%. • The flux recovery ratio of PSf/GO-vanillin membrane is 90% for landfill leachate wastewater. [ABSTRACT FROM AUTHOR]

Two-pass reverse osmosis desalination is a common process to treat high-salinity feed solution and provides a low-salinity permeate solution. This study investigated the significance of the energy generated by the dual-stage pressure retarded osmosis (DSPRO) from the reverse osmosis (RO) brine stream. The main components of the DSPRO-RO hybrid system are RO, pressure retarded osmosis (PRO), and energy recovery device, and their models are determined. Dymola software, using Modelica modelling language, was utilized for solving the hybrid system models. Two different flowsheets were built; the first included a two-pass RO, while the second is a hybrid of a two-pass RO (2RO)-DSPRO system. Seawater salinities of 40 and 45 g/L were the RO feed solution, and 1 g/L tertiary treated wastewater was the feed solution of the DSPRO process. The net specific energy consumption was calculated for the 2RO and 2RO-DSPRO systems for 40 and 45 g/L salinities. At a 47 % recovery rate and 40 g/L seawater salinity, the 2RO-DSPRO system was 14.7 % more energy efficient than the 2RO system. The corresponding energy saving at a 47 % recovery rate and 45 g/L seawater salinity was 17.5 %. The desalination energy for the 2RO system was between 3.25 and 3.49 kWh/m3, and for the 2RO-DSPRO system was between 2.91 and 2.97 kWh/m3. The results demonstrate the great potential of integrating the 2RO with the DSPRO to reduce desalination's energy consumption and environmental impacts. • 2RO-DSPRO was evaluated to reduce the desalination energy at 40 g/L & 45 g/L salinities. • DSPRO-2RO system achieved between 14.7 % & 17.5 % energy saving at 47 % recovery rate. • The desalination energy for 2RO was 3.25–3.49 kWh/m3 and for 2RO-DSPRO was 2.91–2.97 kWh/m3. • The membrane cost should be reduced for an economic PRO process. [ABSTRACT FROM AUTHOR]

In this study, the top layer of commercial UA-60 loose nanofiltration (NF) membranes is coated with cross-linked kappa-carrageenan (κ -CGN) and graphene oxide (GO) solution. Various GO concentrations are investigated to improve salt rejection and antifouling properties. The surface functional groups, surface morphology, elemental analysis, hydrophilicity, and surface charge of all membranes were investigated using a range of analytical tools. Coated membranes are tested for 2000 ppm NaCl (sodium chloride) and MgSO 4 (magnesium sulfate) for salt rejection studies. Landfill leachate wastewater was used for antifouling studies. The κ-CGN-GO coating increased the wettability and negative surface charge, increasing salt rejection. The GO concentration of (0.075; wt/v %) with 1.2 wt% κ -CGN aqueous solution is optimal for coating solution. The optimal UA-60-κ-CGN-GO 3 membrane showed the highest FRR (flux recovery ratio) of 95.73% and the lowest total fouling percentage of 18.9%, with a slightly low water flux compared to the pristine UA-60 membrane. The κ-CGN-GO coating has the potential to overcome membrane fouling and low selectivity for wastewater treatment owing to the increased selectivity and antifouling properties of the coated membranes. [Display omitted] • Commercial UA-60 membrane was modified with k-CGN/GO composite. • GO loading was varied to tune membrane wettability and antifouling properties. • Modified UA-60- κ- CGN-GO composite membranes showed enhanced wettability. • UA-60- κ- CGN-GO composite membranes showed higher selectivity and antifouling properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • CNT/GO-PVA membranes were fabricated to achieve a high rejection rate and water flux. • CNTs were used as nanospacer for CNT/GO-PVA membranes. • Membranes rejection rate and water flux decreased with increasing CNT concentration. • The rejection rate of CNT 5 /GO 15 -PVA 0.5 membrane to Na 2 SO 4 reached 94.2% Two-dimensional (2D) graphene oxide (GO)-based materials with tunable physicochemical properties have enormous potential for developing next-generation desalination membranes. Nevertheless, weak interlamellar interactions result in poor selectivity towards small ions, limiting the wide applicability of GO membranes. Controlling the swelling of the GO membrane while maintaining high permeability and selectivity is a significant scientific and technological challenge. To address the issues above, we used one-dimensional (ID) carbon nanotubes (CNT) as a nano-spacer and polyvinyl alcohol (PVA) as an adhesive. Synergistic ionic complexation between 1D-CNT, 2D-GO, and PVA was studied using various analytical techniques. The intercalation of CNT between GO nanosheets and the cross-linking of CNT/GO-PVA significantly improved the separation performance. Pressure-assisted filtration was used to coat the CNT/GO-PVA on hydrophilic mixed cellulose esters (MCE) support with pore size 0.22 µm to obtain a highly ordered laminated structure. Five minutes of mild annealing at 80 °C narrowed the laminar channels of the GO nanosheets by transforming the oxygen-containing functional groups. In a dead-end filtration unit, the CNT 5 /GO 15 -PVA 0.5 composite membrane exhibits a high rejection of 94.2% to sodium sulphate (Na 2 SO 4) and 85.86% to sodium chloride (NaCl), accompanied by a high permeate rate of 14.2–13.45 LMH at 5 bar operating pressure. The salt rejection studies were evaluated for continuous operation for 72 h for all membranes. Due to the synergistic effect of CNT, GO, and PVA, prepared membranes demonstrated the potential for practical water separation applications with desired permeability and selectivity. [ABSTRACT FROM AUTHOR]

This study reports landfill leachate treatment by the forward osmosis (FO) process using hydrogen peroxide (H 2 O 2) for membrane cleaning. Although chemical cleaning is an effective method for fouling control, it could compromise membrane integrity. Thus, understanding the impact of chemical cleaning on the forward osmosis membrane is essential to improving the membrane performance and lifespan. Preliminary results revealed a flux recovery of 98% in the AL-FS mode (active layer facing feed solution) and 90% in the AL-DS (draw solution faces active layer) using 30% H 2 O 2 solution diluted to 3% by pure water. The experimental work investigated the effects of chemical cleaning on the polyamide active and polysulfone support layers since the FO membrane could operate in both orientations. Results revealed that polysulfone support layer was more sensitive to H 2 O 2 damage than the polyamide active at a neutral pH. The extended exposure of thin-film composite (TFC) FO membrane to H 2 O 2 was investigated, and the active layer tolerated H 2 O 2 for 72 h, and the support layer for only 40 h. Extended operation of the TFC FO membrane in the AL-FS based on a combination of physical (hydraulic flushing with DI water) and H 2 O 2 was reported, and chemical cleaning with H 2 O 2 could still recover 92% of the flux. [Display omitted] • Oxidative tolerance of forward osmosis membrane was investigated for the first time. • Hydrogen peroxide provided 92% water flux recovery after 72 h of landfill filtration. • The active membrane layer can withstand hydrogen peroxide of 3% concentration for 72 h. • The support layer of the FO membrane can withstand hydrogen peroxide for 40 h only. [ABSTRACT FROM AUTHOR]