ABSTRACT
The effective simultaneous treatment of hazardous waste sludge and complex oil/water emulsions in one way is urgently desired but still a challenging issue. Herein, this work for the first time presents a green and efficient strategy to fabricate an electroplating sludge (ES) derived multifunctional self-supporting membrane for the one-step removal of emulsified oils, soluble metal ions, and anions in complex oily wastewater. Due to low cost of ES and sustainability of the solvent selected in fabrication process, the large-scale application of the membrane is easily to promote. The assembled hierarchical nanostructure endowed robust underwater superoleophobicity of the membrane even under various corrosive aqueous environments, as well as excellent ultra-low oil adhesion and anti-oil-fouling performance, without chemical modification. Significantly, the multifunctional membrane possessed desirable simultaneous separation efficiency for five typical oil-in-water emulsions (>99.4%, high oil/water selective wettability), including crude oil-in-water emulsion with high viscosity (>99.6%), Cu2+ (>96.1%, surface complexation and ionic exchange), and Cl- (>92.7%, electrostatic attraction). Therefore, this green, low-cost, and multifunctional membrane not only allows the large-scale resource utilization of hazardous waste sludge, but also effectively solves the problems of complex oily wastewater purification.
ABSTRACT
Facing the increasingly complex and deteriorated environment, people's thermal comfort and health requirements are expanding. Therefore, wearable materials with integrated functions have progressed rapidly due to the fair compatibility for various functions and precise regulation. In this work, a laminated MXene foam/cellulose@LDH composite membrane was fabricated via a facile process consisting of in situ growth, vacuum filtration, and foaming for asymmetrical personal thermal management and electromagnetic interference shielding. In detail, the Zn-Al LDH side shows a high solar reflectance of 0.89 and an infrared emissivity of 0.97 in the atmospheric window, demonstrating the superior radiative cooling property. In contrast, the outstanding radiative warming performance is revealed by the high solar absorption (0.72) and infrared reflectivity (0.55) of the MXene foam. As a result, prominent temperature differences were achieved during the validation test. Compared to the control group, an 18 °C reduction of the Zn-Al LDH side and a 9.6 °C increment of the MXene foam side were observed, bringing out the excellent optical properties and radiative thermal management performances. What is more, due to the outstanding electrical conductivity of MXene, a rapid and prominent temperature rise to 44.2 °C could be expected by applying a low voltage of 1 V to provide active joule warmth. In addition, hydrophobization and the associated stain resistance were explained by the high water contact angles of obtained membranes. The excellent electromagnetic interference shielding performance (43.9 dB) given by the introduction of MXene provides a prospective candidate to replace the common shielding materials. The results, in general, provide a promising strategy for meeting the updating requirements for comfortable living in a world full of potential thermal and health threats.
ABSTRACT
The effective treatment of complex oily wastewater is of great significance but still a considerable challenge, since single-function, expensive reagents, and complicated process have emerged as shackles for practical applications. Herein, with the objective to waste-control-waste, we proposed a facile and sustainable strategy to fabricate a low-cost multifunctional layer from hazardous waste aluminum sludge (WAS) for complex oily wastewater management. The as-designed layered double oxides/WAS (LDOs/WAS) layer with three-dimensional (3D) hierarchical rough surface exhibited excellent underwater superoleophobicity even under corrosive conditions and low adhesion to oil without any chemical modification reagent treatment. Significantly, the layer can be applied to gravity-directed simultaneous efficient oil-in-water emulsions and anions (taking phosphate as an example) separation with a separation efficiency for emulsion and phosphate up to 99.4% and 99.1%, respectively, and a high separation flux of above 2585 L m-2 h-1. Notably, the flux can be controlled simply and flexibly by adjusting the thickness of the layer. Furthermore, the layer also displayed excellent thermal stability, chemical stability, durability and recyclability. Therefore, this work not only presents a promising approach to design sludge-based multifunctional materials for complex oily wastewater remediation, but also shows great potential and value in environmental pollutions reduction and industrial applications.
