Enhancement of Industrial Effluents Quality by Using Nanocomposite Mg/Al LDH Ultrafiltration Membranes

Calcium-doped magnetic humic acid nano particles for the efficient removal of heavy metals from wastewater: the role of Ca

Ca doping is an effective method for improving the adsorption capacity of HA-Fe aggregates and regulating their structures. Understanding the structural characteristics of Ca-HA-Fe aggregates can help explore their microscopic adsorption effect on heavy metals. However, the heterogeneity of HA results in an incomplete understanding of the structural characteristics of the ternary system of Ca-HA-Fe aggregates and adsorption of the quaternary system of Ca-HA-Fe-Pb/Cu/Cd. In this study, interactions between Ca-HA-Fe ternary and Ca-HA-Fe-Pb/Cu/Cd quaternary systems were discussed from a molecular perspective. The structures of the basic structural units of HA were identified. Density functional theory (DFT) was employed to calculate the stable states of basic structural units of HA and Ca2+. The results showed that hydroxyl and carboxyl groups exhibited the highest capacity to bind with Ca2+. The interactions among Ca, HA, and Fe led to the formation of network aggregates. The binding energies of functional groups for heavy metals and the feasibility of ion exchange were calculated by the method of experiment and DFT. According to the contribution of functional group complexation and ion exchange, the ion exchange values for Pb2+, Cu2+, and Cd2+ were 66.71%, 62.87%, and 60.79%, respectively, which indicated that Ca2+ ion exchange showed considerable potential in enhancing the adsorption capacity of heavy metals.

Bi2WO6 nanoparticles anchored on membrane by grafting via in-situ polymerization for the treatment of antibiotic and pesticides wastewater

Antibiotics, natural organic matter, and pesticides are detected in the ecosystem's domestic water, surface water, and groundwater and are largely applied in pharmaceuticals and agriculture. Polymeric membranes are effectively remove the various pollutants in the water bodies, but fouling is one of the major limitations of commercial membranes. Herein, we modified the polymeric membrane surface with inorganic photocatalytic nanoparticles. In this work, the hydrothermal method is used for the synthesis of Bi2WO6 nanoparticles and as-synthesized nanoparticles grafted onto the various polymeric membranes, including polyetherimide (PEI), cellulose acetate (CA), polyvinylidene fluoride (PVDF), and polysulfone (PSF). The functional group studies confirmed the existence of nanoparticles and hydroxyl groups on the hybrid membrane. Further, finger-like voids, top-surface morphology, and roughness on the membrane surface were validated via Field Emission Scanning Electron Microscopy (FESEM) and Atomic force microscopy (AFM), respectively. The significant rejection of tetracycline, humic acid, and fulvic acid + atrazine was noted with the synthesized membranes in the following order: PVDF (81.1%, 78.8%, 80.6%) > CA (70.1%, 69.3%, 71.7%) > PSF (72.5%, 73.6%, 67.1%) > PEI (75.9%, 65.5%, 63.7%). The photodegradation efficiency of hybrid membranes against tetracycline, humic acid, and fulvic acid + atrazine was observed in the order: PEI (28.5%, 25.8%, 30.2%) < CA (46.5%, 42.4%, 40.5%) < PSF (46.9%, 37.7%, 44.7%) < PVDF (67.7%, 62.1%, 64.3%). These membranes exhibit an outstanding permeate flux recovery ratio to the neat membrane. Therefore, the grafting of Bi2WO6 nanoparticles creates a potential bonding with PVDF membranes than other polymeric membranes, thus exhibiting an outstanding rejection than hybrid and neat membranes.

A Comparative Study of the Self-Cleaning and Filtration Performance of Suspension Plasma-Sprayed TiO2 Ultrafiltration and Microfiltration Membranes

This study investigated the performance of photocatalytic titanium dioxide microfiltration membranes with an average pore size of approximately 180 nm and ultrafiltration membranes with an average pore size of around 40 nm fabricated with the suspension plasma spray process. The membranes were evaluated for their filtration performance using SiO2 particles of different sizes and polyethylene oxide with molecular weights of 20 kDa to 1000 kDa, and the fouling parameters were characterized. The rejection rate was enhanced by increasing the thickness of the membranes. This effect was more pronounced with the ultrafiltration membranes. The rejection rate of the ultrafiltration membrane was improved significantly after filling the larger pores on the surface with agglomerates of titanium dioxide nanoparticles. The self-cleaning performance of the membranes was assessed under visible light. Both ultrafiltration and microfiltration membranes showed a flux recovery under visible light illumination due to the photocatalytic activity of titanium dioxide. The membranes also show a flux recovery of more than 90%.

Boosting brackish water treatment via integration of mesoporous γ-Al2O3NPs with thin-film nanofiltration membranes

In this study, a simple method based on non-ionic surfactant polysorbates-80 was used to create mesoporous γ-Al₂O₃NPs. The properties of the prepared mesoporous alumina nanoparticles (Al₂O₃NPs) were verified using ATR-FTIR, XRD, SEM, TEM, DLS, and BET surface area analysis. Then, thin-film nanocomposite (TFN) nanofiltration membranes were fabricated by interfacial polymerization of embedded polyamide layers with varied contents (0.01 to 0.15 wt.%) of mesoporous γ-Al₂O₃NPs. The surface roughness, porosity, pore size, and contact angle parameters of all the prepared membranes were also determined. The performance of the fabricated membranes was investigated under various mesoporous γ-Al₂O₃NPs loads, time, and pressure conditions. Mesoporous γ-Al₂O₃NPs revealed an important role in raising both the membrane hydrophilicity and the surface negativity. The addition of 0.03 wt.% mesoporous γ-Al₂O₃NPs to the TFN membrane increased water flux threefold compared to the TF control (TFC) membrane, with maximum water flux reaching 96.5, 98, 60, and 52 L/(m².h) for MgSO₄, MgCl₂, Na₂SO₄, and NaCl influent solutions, respectively, with the highest salt rejection of 96.5%, 92.2%, 98.4%. The TFN-Al₂O₃ membrane was also able to soften water and remove polyvalent cations such as Mg²⁺ with a highly permeable flux. The TFN-Al₂O₃ membrane successfully removed the hardness of the applied water samples below the WHO limit compared to using merely the TFC membrane. Furthermore, the TFN-Al₂O₃ nanofiltration membrane unit proved to be a promising candidate for the desalination of real brine like that collected from the Safaga area, Egypt.

Fabrication of cerium titanate cellulose fiber nanocomposite materials for the removal of methyl orange and methylene blue from polluted water by photocatalytic degradation

In this study, cellulose fibers (Cf), extracted from sunflower seed husk, and different molar ratios of cerium titanate (Ce-Ti) NPs were prepared from sunflower seed husk extract by a green biosynthesis approach. Cf and Ce-Ti NPs were reacted via cross-linking reaction to synthesize a novel nanocomposite photocatalyst of Ce-Ti/Cf. Using Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM-EDX) spectroscopy, all manufactured materials were characterized. The results obtained from FTIR and EDX analyses indicated that Cf and its nanocomposites (0.1 Ce-Ti/Cf, 0.3 Ce-Ti/Cf, and 0.5 Ce-Ti/Cf) were successfully prepared by harnessing biomass extract from sunflower seed husk. Furthermore, XRD revealed that the degree of crystallinity of the nanocomposites was enhanced by increasing the molar ratios of the Ce-Ti NPs. The photocatalytic activity of as-fabricated 0.1 Ce-Ti/Cf, 0.3 Ce-Ti/Cf, and 0.5 Ce-Ti/Cf nanocomposite samples was investigated on methylene blue (MB) and methyl orange (MO) dyes as model organic compounds found in wastewaters. The effects of dose, contact time, and pH on the photocatalytic activity of the synthesized nanocomposites, the photodegradation kinetic parameters of MB, and MO degradation with/without the addition of H2O2 were also studied. The results revealed that high photodegradation efficiency could be obtained as the ratio of TiO2 in the Ce-Ti nanocomposite formula increases. Moreover, after sunlight irradiation, the adsorption capacity and the dye decomposition ratio significantly increase during the early contact time and reach equilibrium at about 240 and 120 min for 0.5 Ce-Ti/Cf nanocomposite photocatalyst in the absence and presence of hydrogen peroxide, respectively. In light of the obtained results and the practical wastewater treatment study conducted, the prepared photocatalyst from Ce-Ti/Cf nanocomposites could be a promising material for treating dye wastewater especially collected from Egypt.

Green synthesis of ZnO, MgO and SiO2 nanoparticles and its effect on irrigation water, soil properties, and Origanum majorana productivity

The synthesis of different metal oxide nanoparticles (NPs) (e.g., ZnO, MgO and SiO₂) using green methods is a promising alternative to traditional chemical methods. In this work, ZnO, MgO, and SiO₂ NPs were prepared using lemon peel extract. The synthesized NPs were characterized using Fourier transform infrared spectroscopy, UV–Visible spectroscopy, X-ray diffraction, and transmission electron microscopy. Also, the effects of the green synthesis of different NPs on the irrigation water quality, the availability of some heavy metals in soil and plants, and the productivity of Origanum majorana (marjoram) were studied in detail. The obtained results showed that the addition of the NPs resulted in noticeable variations in the removal percentages of Cu²⁺ and Fe³⁺ from aqueous solutions. The maximum values obtained for the adsorption of Cu(II) on ZnO, MgO, and SiO₂ NPs within the pH values of 3–5 were 89.9%, 83.3%, and 68.36%, respectively. Meanwhile, the maximum adsorption values of Fe(III) at pH 3.3 were 82%, 80%, and 65% for ZnO, MgO, and SiO₂ NPs, respectively. Clearly, the application of the NPs effectively reduced the available Cu²⁺ in the studied soil samples in the following order: Zn2 > Zn1 > Mg2 > Si2 > Mg1 > Si1 > C (control). The highest values of available Cu²⁺ were observed in the control treatment, whereas the lowest values were obtained when Zn2 was added. The same tendencies were observed with substantial concentrations of Fe. The addition of NPs to the soil samples positively affected the plants' Cu²⁺ uptake. The effects of NPs and the additions of Cu²⁺ and Fe³⁺ on the availability of nitrogen, phosphorus, and potassium (NPK) in the soil system were very completed and osculated from one treatment to another. The same tendencies were observed with the total concentration of NPK in plants.

High-flux TFN nanofiltration membranes incorporated with Camphor-Al2O3 nanoparticles for brackish water desalination

A new approach of highly fluxes thin film nanocomposite (TFN) nanofiltration (NF) membranes is reported. The fabricated module was made by incorporation of commercial-Al₂O₃ (CO.TFN) and camphor-Al₂O₃NPs (CA.TFN) into polyamide layers throughout the interfacial polymerization method. A simple biological reduction technique was adopted in preparation of camphor-Al₂O₃ NPs by using CinnamomumCamphora (CC) leaf extract. The crystallography of the commercial and camphor-Al₂O₃ NPs was examined by XRD and FTIR analyses. The CO.TFN and CA.TFN membranes were characterized by determining their surface roughness, pore size, porosity, zeta potential and contact angle parameters. The morphology and the cross-sectional of the NF membranes were studied by atomic force microscope (AFM) and scanning electron microscope (SEM). NF performance was investigated at various Al₂O₃ NPs loads, applied pressure, and time. The results, of the membranes fabricated at low cost, showed the high permeable flux and elimination of multivalent cations (Mg²⁺, Ca²⁺, and water softening). Incorporating 0.98 mM of camphor-Al₂O₃ NPs into the TFC membrane increased the water flux up to 4 times compared to only 1.5 times for commercial-Al₂O₃ NPs. Moreover, the salt rejection of CO.TFN and CA.TFN NF membranes increased to 95.1% and 96.5%, respectively for the feed solution (2 g/L Na₂SO₄ at 25 °C). The optimized NF membrane module of 0.98 mM camphor-Al₂O₃-NPs (CA.TFN) shows the maximum water flux 69.0,62.2, 60.5 and 55.4 L/m².h for the feed solutions of following salts NaCl, Na₂SO₄, MgCl₂ and MgSO₄ with high salt rejections 92.4%, 96.5%, 91.7% and 95.3%, respectively. This proves that camphor-Al₂O₃ NPs have a significant role in increasing the membrane hydrophilicity. Hence, the CA.TFN membrane module proved to be a promising candidate for the real brackish water desalination as that collected from Marsa Alam, Egypt.