Guoliang Xu,Mingming Wu,Taotao Ji,Chen Wang,Sixing Chen,Yi Liu
Although having shown great promise in gas separation, reverse osmosis , and nanofiltration , preparation of carbon membranes, which commonly involves elaborate high-temperature pyrolysis or exfoliation-reassembly, still suffers from complicated fabrication procedure and/or high production cost. In this study, we pioneered the preparation of continuous asymmetric carbon membrane through facile mechanical rubbing of a pencil graphite. Among them, 2B-type pencil with 64 wt% graphite exhibited superior nanofiltration performance (Congo Red rejection rate of 99.4% and water flux of 21.91 L·m −2 ·h −1 ·bar −1 ). Long-time operation confirmed its excellent stability. Of particular note, the spent membrane could be facilely recovered by erasing, resulting in not only zero pollutant discharge but also full recovery and reutilization of the substrate. The above protocol is anticipated to pave an avenue for facile and sustainable production of versatile carbon membranes with superior separation performances.
Rong Wang,Xiaohua Jia,Ding Wang,Xinyue Duan,Haojie Song
With the increasing complexity of mechanical equipment service conditions, the conventional single-component lubricant fillers have been difficult to meet the needs of practical applications, and it is necessary to explore new solutions. To this end, in this study, cellulose-based self-lubricating films (G-GNPs/EC) synergistically reinforced with graphite and graphene were prepared by in situ exfoliation of flake graphite by cellulose. During the friction process, graphite can either act as a load-bearing subject or form a lubrication transfer film to achieve wear compensation, while graphene layers retard graphite wear, enhancing interfacial stability. The resulting material achieves a low friction coefficient of 0.104 and superior load-bearing capacity, significantly outperforming the single-lubrication system. Moreover, the “rigid–flexible” hierarchical enhancement structure formed by graphene and esterified cellulose (EC) endows the composite with exceptional mechanical properties, achieving a tensile strength of 99.84 MPa and a toughness of 10.01 MJ/m3. Notably, the waste G-GNPs/EC demonstrates excellent biosafety and environmental friendliness, effectively adsorbing heavy metal ions (Cu2+) from soil. This work provides a feasible way to realize the practical application of high-performance, environmentally friendly self-lubricating materials.
Despite the fact that synthetic adhesives have achieved great progress, achieving robust dry/wet adhesion under harsh operating environments is still challenging. Herein, inspired from the extraordinary adhesion mechanism of nature mussel protein adhesive, the balanced design concept of co-adhesion and interfacial adhesion is proposed to prepare one kind of novel copolymer adhesive of [poly(dopamine methacrylamide-co-methoxethyl acrylate-co-adamantane-1-carboxylic acid 2-(2-methyl-acryloyloxy)-ethyl ester)] [p(DMA-co-MEA-co-AD)], named as super-robust adhesive (SRAD). The SRAD exhibits ultra-high interface bonding strengths in air (∼7.66 MPa) and underwater (∼2.78 MPa) against an iron substrate. Especially, a greatly tough and stable adhesion strength (∼2.11 MPa) can be achieved after immersing the bonded sample in water for half a year. Furthermore, the SRAD demonstrates surprising wet bonding robustness/tolerance even encountering harsh conditions such as fluid shearing, dynamic loading, and cyclic mechanical fretting. The great advantages of SRAD, such as strong interface bonding, stable wet adhesion underwater, and good mechanical tolerance, makes it demonstrate huge application potential in engineering sealants and underwater adhesion.
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