Herein, an emerging vertically oriented alginate aerogel composites (QLHC@A aerogel) was constructed by combining the mild ionic crosslinking technique with directed freeze-casting to achieve adsorptive removal of ReO 4 − (the chemical analogue of TcO 4 − ). The lignin hydrochar in aerogel composites served as a bridge connecting quaternary ammonium groups to fabricate functional addition, among the PDDA-modified lignin hydrochar investigated, QLHC 100 exhibited the best adsorption performance, up to 212.95 mg/g, while the regular lamellar structure and good hydrophilic property of alginate-based aerogel allowed rapid diffusion of ReO 4 − anion in water. When the usage amount of QLHC 100 powder became 0.8 g, the optimal ReO 4 − removal efficiency of QLHC@A aerogel reached 188.90 mg/g at pH 4, 0.1 g/L and 303 K. Batch adsorption experiments also validate that the ReO 4 − adsorption process was mightily pH-dependent behavior, and adsorption behavior fitted both the pseudo-second-order kinetic model and the Langmuir isothermal model well. Meanwhile, QLHC@A aerogel had a high adsorption selectivity, excellent chemical tolerance, and good reuse performance. Based on various characterization techniques and DFT calculation result, the adsorption mechanism of ReO 4 − on QLHC@A aerogel is mainly dominated by electrostatic adsorption and strong affinity between quaternary ammonium groups and ReO 4 − . Significantly, this strategy can be expanded to include high-performance aerogel composites for the remediation of nuclear effluent contaminated with TcO 4 − .
Ning-xiao Wei,Yu-xing Wang,Hua-li Chen,Li-guang Wu,Ting Wang
In an effort to explore the potential application prospects of membrane separation technology in treating nuclear-contaminated wastewater, a TFN nanofiltration membrane incorporating the ZIF-8@Ti 3 C 2 T x nanocomposite was successfully synthesized using the interfacial polymerization method. This involved doping the microemulsion of ZIF-8@Ti 3 C 2 T x into the aqueous (organic) phase. The morphology and structure of ZIF-8@MXene nanocomposites and TFN nanofiltration membranes were characterized. The selective removal of ReO 4 - from simulated radioactive wastewater using the TFN nanofiltration membrane was evaluated. The results indicated that the ZIF-8@Ti 3 C 2 T x composite, uniformly dispersed in the polymer, effectively enhanced the pore structure and polarity of the nanofiltration membrane, thereby improving its permeability. The electronegativity of ZIF-8@Ti 3 C 2 T x also enhanced the negative charge on the surface of the polymer membrane, significantly improving the membrane’s performance in rejecting ReO 4 - while maintaining a low retention rate for Na + . This design facilitates the efficient selection of ReO 4 - from high-salinity wastewater. In addition, the layer spacing of Ti 3 C 2 T x further improved the screening of ReO 4 - and Na + . However, when 0.75 g·L −1 of microemulsion was added, it became challenging to disperse the microemulsion completely in the organic phase. This led to the agglomeration of composites in the nanofiltration membrane, weakening both flux and selectivity. Optimal performance was achieved with a microemulsion doping amount of 0.5 g·L −1 , resulting in the nanofiltration membrane M-O-1 exhibiting the best performance (Jp = 41.92 L·m 2 ·h −1 and R(ReO 4 - ) = 65.81%). Even at a high salt concentration (20 g·L −1 ), the M-O-1 membrane retained approximately 55% of pollutants after continuous operation for 5 h, indicating that the TFN nanofiltration membrane containing ZIF-8@Ti 3 C 2 T x holds significant promise for selectively extracting 99 Tc from wastewater with a high salt content.
危险品化学品经营许可证（带存储）