高浓度Na+//NO3-， SO42——H2O溶液的膜蒸馏结晶耦合过程调控

煤化工、含能材料等工业领域产生的富含硝酸盐、硫酸盐的高浓废水排放量巨大、环境危害严重。高浓度复合盐水低能耗处理的同时实现高品质结晶过程调控,已经成为一个重要的研究方向。针对典型的高浓度Na⁺//NO{}_{\mathrm{3}}^{-}, SO{}_{\mathrm{4}}^{\mathrm{2}-}-H₂O溶液体系,提出利用膜蒸馏结晶耦合技术处理,通过微孔膜界面调控目标盐分的成核能垒,有效控制了典型蒸发结晶过程中多元盐离子扩散差异、爆发成核,避免了形成空心、高杂质离子包藏的晶体,提升了结晶纯度和分离效率;同时,提出在膜蒸馏的优势分离区间内蒸发溶剂,然后再通过减压蒸发结晶的优化设计思路,降低了膜表面结垢和膜孔润湿风险,进一步提升了整个过程能量效率,提高了膜可重复利用率。研究为开发高浓度复合无机盐水处理技术提供了新思路。     

高浓度Na+//NO3-， SO42——H2O溶液的膜蒸馏结晶耦合过程调控

煤化工、含能材料等工业领域产生的富含硝酸盐、硫酸盐的高浓废水排放量巨大、环境危害严重。高浓度复合盐水低能耗处理的同时实现高品质结晶过程调控,已经成为一个重要的研究方向。针对典型的高浓度Na⁺//NO{}_{\mathrm{3}}^{-}, SO{}_{\mathrm{4}}^{\mathrm{2}-}-H₂O溶液体系,提出利用膜蒸馏结晶耦合技术处理,通过微孔膜界面调控目标盐分的成核能垒,有效控制了典型蒸发结晶过程中多元盐离子扩散差异、爆发成核,避免了形成空心、高杂质离子包藏的晶体,提升了结晶纯度和分离效率;同时,提出在膜蒸馏的优势分离区间内蒸发溶剂,然后再通过减压蒸发结晶的优化设计思路,降低了膜表面结垢和膜孔润湿风险,进一步提升了整个过程能量效率,提高了膜可重复利用率。研究为开发高浓度复合无机盐水处理技术提供了新思路。     

Hierarchically porous carbon from biomass tar as sustainable electrode material for high-performance supercapacitors

The byproduct tar from biomass gasification process had seriously impeded development and applications of this technology, thus novel path for biomass tar valorization is had been continuously pursued. Given its high carbon content, this work attempted to convert biomass tar into hierarchically porous carbon by thermal activation with acetate potassium. The optimal product produced with mass ratio of biomass tar to acetate potassium of 1:3 and activation temperature at 800 °C was revealed as excellent electrode material for high-performance supercapacitor, which demonstrated electrochemical capacitance up to 310.4 F/g at 0.2 A/g, whilst preserved 91% of initial capacitance after 5000 charge-discharge circles at current density of 5 A/g. These excellent properties had arisen from the open and hierarchical porosity and large surface area. This work disclosed the great potential of biomass tar as sustainable and competent candidate for fabricating high-performance electrode material for electrochemical energy devices, and may bring up new opportunities to development of biomass gasification technologies.     

Performance of amine-modified CdS-D@ZIF-8 nanocomposites for enhanced photocatalytic H2 evolution

The exploration of an efficient photocatalyst for H₂ evolution directly from water splitting is highly desirable due to the current environmental and energy situation. The present work successfully used a solvothermal method to synthesize organic-inorganic CdS-diethylenetriamine (CdS-D) nanorods (NRs). The amine-modified CdS-D@ZIF-8 nanocomposite materials were prepared using the self-assembly method with different ZIF-8 nanocrystals (NCs) weight ratios. At λ ≥ 420 nm wavelength, the optimized CdS-D@ZIF-8 (CZ-2) nanocomposite with 5.0 wt% loading of ZIF-8 NCs showed the highest performance of 2293.9 μmol g⁻¹ h⁻¹ H₂ evolution and an apparent quantum yield (AQY) of 4.95%. The CZ-2 nanocomposite's activity was 114.69, 5.25, and 1.32 times higher than that of ZIF-8 NCs (20.0 μmol g⁻¹ h⁻¹), CdS-D NRs (436.4 μmol g⁻¹ h⁻¹) and 1.0 wt% Pt/CdS-D (1737.3 μmol g⁻¹ h⁻¹), respectively. The cyclic photostability of the prepared CZ-2 nanocomposite remained unchanged after six consecutive cycles. The UV-DRS, electrochemical measurements, and Mott-Schottky (MS) analysis were performed to explain the band edge positions for CdS-D NRs and ZIF-8 NCs. The detailed S-scheme charge transfer mechanism of the as-prepared catalysts was also studied using the density functional theory (DFT). This work provides vital information for the controllable synthesis of ZIF-8-modified S-scheme nanocomposites for solar energy utilization.