Stable graphene oxide-halloysite composite membrane with enhanced permeability for efficient dye desalination

Cost-Effective and Scalable Solar Interface Evaporators Derived from Industry Waste for Efficient Solar Steam Generation

Interfacial solar steam generation for sustainable and eco-friendly desalination and wastewater treatment has attracted much attention. However, costly raw materials and complex preparation processes pose constant challenges to its wide promotion. Herein, a novel, cost-effective, and scalable strategy is presented for preparing solar interface evaporators using industrial waste as a raw material. Modified polyethylene foam evaporators (M-EPEs) are simply prepared by drilling and then hydrophilic modification of industrial waste (EPE-1). M-EPEs not only retain the strong mechanical properties and thermal insulating properties (0.047 W·m-1·K-1) of EPE-1 but also exhibit superhydrophilicity and strong light absorption (over 90%). M-EPEs achieve a high evaporation rate of 1.497 kg·m-2·h-1 and photothermal efficiency of up to 93.8% under 1 kW·m-2 solar illumination. Moreover, it has excellent stability and salt tolerance. Our work addresses the environmental issues of recycling polyethylene waste and provides a facile and efficient strategy for designing low-cost, large-scale solar interface evaporators for desalination.

D-spacing controllable GO membrane intercalated by sodium tetraborate pentahydrate for dye contamination wastewater treatment

Sodium tetraborate pentahydrate (STB) was intercalated into graphene oxide (GO) nanosheets to form a nanocomposite (STB@GO). Subsequently, it was self-assembled on a substrate membrane to prepare STB@GO nanofiltration membrane. The properties of the STB@GO powder samples and the nanofiltration membrane were studied using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), contact angle (CA), and zeta potential. When the STB concentration was 1.0 g/L in the cross-linking reaction, the membrane was described as the STB₂@GO membrane and exhibited a large interlayer space (d-spacing = 1.347 nm), high hydrophilicity (CA = 22.2°), and high negative potential (zeta = -18.0 mV). Meanwhile, the pure water flux of the membrane was significantly increased by 56.60% than that of the GO membrane. In addition, the STB₂@GO membrane exhibited a favorable capability for dye rejection,98.52% for Evans blue (EB), 99.26% for Victoria blue B (VB), 91.94% for Alizarin yellow (AY), and 93.21% for Neutral red (NR). Furthermore, the STB₂@GO membrane performed better in dye separation under various types and concentrations of dye, pH values, and ions in solution. Thus, this study provides a promising method for preparing laminated GO nanofiltration membranes for dye wastewater treatment.

Novel Perylene-3, 4, 9, 10-tetracarboxylic dianhydride modified Zr-MOFs/Graphene oxide membrane for dye wastewater treatment

A new type of composite membrane was prepared through the vacuum filtration self-assembly, in which, graphene oxide (GO) was the basic material, and the horizontal insertion material is product of perylene-3, 4, 9, 10-tetracarboxylic dianhydride (PTCDA) and UiO-66-NH₂ (PTCDA-UiO-66-NH₂). The leading role of Π-Π conjugate, auxiliary effect of hydrogen bonding during membrane preparation have been confirmed through Fourier transform infrared spectroscopy (FTIR), UV-visible spectrophotometer, Raman spectroscopy, and X-ray diffraction (XRD). The prepared GO@PTCDA-UiO-66-NH₂ membrane had new nodular structure compared to GO membrane by scanning electron microscopy (SEM) and atomic force microscopy (AFM), which promoted the water transport. In addition, the insertion of PTCDA-UiO-66-NH₂ narrowed the actual filtration spacing between GO sheets, and PTCDA-UiO-66-NH₂ could also adsorbed dye laterally. Experiments showed that the permeance of GO@PTCDA-UiO-66-NH₂ membrane was 1.7 times of GO membrane, and the removal of methyl blue, congo red, crystal violet and disperse black 9 was close to 100%. Under extreme pH, high salt concentration and multiple recycling, its separation ability was still excellent. The GO@PTCDA-UiO-66-NH₂ membrane constituted a unique synergistic structure of vertical-screening and horizontal-adsorption, which successfully overcame the trade-off effect and obtained excellent stability of structure and performance. Therefore, GO@PTCDA-UiO-66-NH₂ membrane had great potential in practical applications.