Yi Sun,Yudan Yuan,Xianwei Geng,Chi Han,Shenkai Lu,Ivona Mitrovic,Li Yang,Pengfei Song,Cezhou Zhao
A simple hydrothermal reaction of Ti 3 C 2 T x and reduced graphene oxide (rGO) nanosheets to adjust the pore size of activated biomass materials (pleurotus eryngii) is presented. The unique structure produced is favourable for the ion transmission and reducing the restacking of Ti 3 C 2 T x and rGO nanosheets. The effect of the addition quantities of Ti 3 C 2 T x /rGO hydrogel on the specific capacitance is investigated. Under the optimal condition, the best specific capacitance of 403 F g −1 is observed at 2 mV s −1 , which is approximately 1.5 times higher than that of the pure activated pleurotus eryngii. Our work possesses a technological strategy to reuse the commercial activated biochar as it can lead to broad industrial applications.
Le Shi,Sihua Liu,Wei-Song Hung,Wenxiong Shi,Xiaolong Lu,Chunrui Wu
To improve the selectivity of nanofiltration membranes (NFMs) for multi/monovalent anions, including SO 4 2− /Cl − , a strategy to moderately amplify the pore size while maintaining chargeability of the membranes was proposed. Four diamine monomers based on piperazine ring, with reaction site distance increased from 2.8 Å to 5.1 Å, were adopted and the effect of the monomer structure especially the reaction site distance on the structure and performance of the NFMs was studied. Position annihilation spectroscopy and molecular dynamics simulation were adopted to provide thorough characterization of the separation layer of the NFMs. The results showed that NFMs prepared by monomers with moderately increased reaction site distance displayed a moderately amplified pore size, which could facilitate the penetration of Cl − and thus improve SO 4 2− /Cl − separation ability. The Na 2 SO 4 /NaCl selectivity got 10.0 with water permeability up to 18.5 L m −2 h −1 bar −1 , exceeding the upper-bound of permeation flux and Na 2 SO 4 /NaCl selectivity of membranes prepared by traditional interfacial polymerization.
The high-temperature industrial waste oil treatment has put forward new requirements for membrane materials. Poly (tetrafluoroethylene) (PTFE) is regarded as the excellent membrane material for membrane process, due to its excellent properties. Herein, the reinforced PTFE hollow fiber membrane (PTFE-HFM) was prepared by the combination of wrapping and heat setting technology. The objection of this study was focusing on the outstanding chemical and thermal resistance of PTEF-HFM for overcoming harsh waste oil treatment. PTFE-HFM exhibited better chemical resistance in the experiment of acid and alkali compared to PVDF-HFM, which the surface of PVDF-HFM corroded obviously and none of PTFE-HFM. The pore size and porosity were precisely adjusted by heat setting technology. Firstly, the morphologies of PTFE-HFM was investigated by scanning electron microscopy, which exhibited favorable interfacial bonding state between PTFE separation layer and supporting layer. Subsequently, the prepared membranes exhibited high-temperature waste oil permeability of 195 L m −2 h −1 bar −1 with only 3% attenuation in long-term operation. Besides, the rejection of lubricants contained activated carbon also reached to 99%. Overall, the facile preparation and excellent performance of robust reinforced PTFE-HFM highlights its great potential in treating high-temperature waste oil.
Polychlorinated biphenyls (PCBs) are persistent organic pollutants that pose a severe threat to the environment and organisms, even at trace levels. In this study, we used carboxylated covalent organic frameworks (COFs) as molecular probes for the extraction of trace PCBs using solid-phase microextraction (SPME). Benefiting from the flexible and adjustable features of the COFs, a series of carboxylated COFs with different pore sizes were tailored and fabricated as SPME fibers. The carboxylated COFs presented significant extraction sensitivity and specificity compared to the pristine COFs, which were attributed to the interplay of twisted nanochannels and formed secondary nanopores, as well as the intermolecular hydrogen bonding between COFs and PCBs. The limits of detection (LODs) were calculated to be 0.02–0.2 ng L–1, which were much lower than the maximum content of PCBs in drinking water recommended by the United States Environmental Protection Agency (USEPA) (0.5 μg L–1). Furthermore, SPME probes were successfully performed for PCB detection in real water samples with satisfactory results. This study demonstrated the potential of carboxylated COF-based SPME fibers for the selective extraction of PCBs and could contribute to the development of new and effective SPME coatings for the efficient detection of pollutants in environmental samples efficiently.
危险品化学品经营许可证（带存储）