Photogenerated-hole scavenger for enhancing photocatalytic chalcopyrite bioleaching

The effects of photogenerated-hole scavengers (ascorbic acid, oxalic acid, humic acid and citric acid) on chalcopyrite bioleaching in the presence of visible light were studied using Acidithiobacillus ferrooxidans (A. ferrooxidans). Four sets of bioleaching experiments were performed: (1) visible light + 0 g/L scavenger, (2) visible light + 0.1 g/L of different scavenger (ascorbic acid, oxalic acid, humic acid and citric acid), (3) dark + 0.1 g/L of different scavenger (ascorbic acid, oxalic acid, humic acid and citric acid), and (4) dark + 0 g/L scavenger (control group). The results showed that ascorbic acid and oxalic acid could act as photogenerated-hole scavengers and significantly enhance chalcopyrite bioleaching under visible light. The dissolved copper in the light group without scavenger was only 18.7% higher than that of the control group. The copper extraction rates of the light groups with oxalic acid and ascorbic acid were respectively 30.1% and 32.5% higher than those of the control group. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analyses indicated that ascorbic acid and oxalic acid as photogenerated-hole scavenger could capture photo-generated holes and inhibit jarosite formation on the chalcopyrite surface, thereby enhancing bioleaching of chalcopyrite under visible light.     

不同紫外波长对热塑性淀粉塑料表面的光交联改性研究

为有效提高热塑性淀粉塑料（TPS）的力学和耐水性能，本文提出用不同波长的紫外光照的方法来实现TPS表面的光交联改性。将光引发剂2,4,6?三甲基苯甲酰基二苯基氧化膦（TPO）的乙醇溶液涂覆于TPS表面后进行紫外光照射，研究了不同紫外光波长（254、308、365 nm）对TPS交联度、力学性能、动态力学性能、耐水性和吸湿性的影响。结果表明，与254 nm和365 nm紫外光照后的样品相比，308 nm光照后TPS样品的拉伸、弯曲和冲击强度最大，分别为4.1 MPa，2.7 MPa和96.8 kJ/m²;TPS中淀粉富集区的玻璃化转变温度（T_α）、甘油富集区的玻璃化转变温度（T_β）分别达最高为-37.48 ℃和50.32 ℃，表面接触角最大为75 °，吸水性能也得到显著改善，交联度结果证实此时形成了最佳的交联结构。     

Experimental evaluation of Pt/TiO2/rGO as an efficient HER catalyst via artificial photosynthesis under UVB & visible irradiation

The study investigated the synergistic effects of rGO and Pt over TiO₂ for the HER via artificial photosynthesis under UVB and visible light irradiation. The introduction of glycerol and industrial wastewater to the system as sacrificial reductants signifies that the major reaction pathway is photocatalytic partial water splitting. The material characterizations revealed successful heterojunction formation and provided insight into chemistry behind the activity of the photocatalysts. Amongst various combinations of rGO on TiO₂, 1GNT exhibited an HER yield five times that of bare TiO₂ under UVB light. Addition of Pt led to the formation of a strong Schottky barrier at the heterojunction and consequently boosted HER performance. 1P0.5 GT presented the highest of 28.5 mmol g⁻¹ h⁻¹ with glycerol and 9.6 mmol g⁻¹ h⁻¹ with wastewater under UVB light respectively. For both binary and ternary photocatalysts, the HER performances dwindled under visible light irradiation, accentuating the insufficient activation of the TiO₂. In addition, 1PT outperformed all the other photocatalysts thereby elucidating the impression that rGO and Pt does not work well together in enhancing HER despite quenching the exciton recombination rate of TiO₂ significantly. The role of pH in the synthesis and the experiments has been discussed. Finally, the underlying mechanisms in the photodeposition and photoreformation have been proposed.     

CNT/g‐C3N4 photocatalysts with enhanced hydrogen evolution ability for water splitting based on a noncovalent interaction

Graphite carbon nitride (g‐C₃N₄) as a novel photocatalyst has attracted growing attention, but its photocatalytic efficiency should be further improved. Based on the large work function and fast electron conductivity of carbon nanotubes (CNTs), here CNT/g‐C₃N₄ photocatalysts with improved H₂ evolution ability and stable water splitting ability were synthesized. The improvement was attributed to the synergistic effect between CNTs and g‐C₃N₄. As for the mechanisms, CNTs strongly attracted photoelectrons and, because of excellent conductibility, rapidly transferred photoelectrons from the catalyst interface. Thereby, the photoelectron migration rate and the photogenerated charge separation and the use efficiency of photoelectrons in g‐C₃N₄ were improved, which largely enhanced the hydrogen production ability. Moreover, the addition of CNTs improved the service life and stability of g‐C₃N₄‐based photocatalytic H₂ production. After 10 hours of visible light irradiation, the maximum H₂ yield from the 12‐mg/L CNT/g‐C₃N₄ (CG12) was 138.7 times larger than that of g‐C₃N₄ (6548.4 vs 47.2 μmol/g), and the H₂ evolution rate was 138.7 times that of g‐C₃N₄ (654.8 vs 4.72 μmol/g/h). After 50 hours, the apparent quantum efficiency of CG12 was up to 37.9%, indicating that the addition of CNTs improved the photocatalytic splitting and stability of g‐C₃N₄. The mechanism of photocatalytic hydrogen production and the roles of CNTs in improving water splitting were discussed through characterization and activity experiments. It was found that the addition of CNTs accelerated the migration, separation, and utilization of photoelectrons and thereby significantly enhanced the photocatalytic performance.     

Importance of the color of light for the illumination of urban squares

The objective of this article was to establish the significance of parameters relevant for urban square illumination, particularly those related with the color of light. Performed using a questionnaire and with 154 architecture students as respondents, the survey showed that the 18 parameters can be divided into two groups. The first group of 13 parameters refers to the overall impression, influencing the basic and most important lighting aims like safety, security, orientation, visual comfort, and amenity, whereas the second group includes parameters related to lighting features which may negatively influence the overall impression. The four parameters directly linked to the color of light were evaluated lower than expected, indicating that architecture students were probably translating their attitude toward color in architecture to color of light, thus underestimating this lighting parameter. The survey results also showed that female respondents are more sensitive to parameters, which affect safety and security.     

Thermodynamic and Surface Properties of Aqueous 1-Dodecyl-3-Methylimidazolium Chloride [C12mim][Cl] Solution in the Presence of a Series of Inorganic Salts

The micellization behavior of amphiphiles is a well-analyzed physicochemical phenomenon, which can be easily influenced by various parameters such as pressure, temperature, and the presence of different additives. Inorganic salts are able to affect the thermodynamic and surface properties of amphiphiles significantly. The effect of a series of salts as additives namely lithium chloride (LiCl), potassium chloride (KCl), sodium chloride (NaCl), sodium bromide (NaBr), and sodium iodide (NaI) on interfacial chemical characteristics of the surface-active ionic liquid (SAIL) 1-dodecyl-3-methylimidazolium chloride [C₁₂mim][Cl] in aqueous solution were examined through conductance, surface tension, fluorescence, ¹H NMR, and dynamic light scattering measurements. The interfacial and thermodynamic parameters of all investigated SAIL-salt systems were evaluated from surface tension and conductance measurements, respectively. A detailed analysis of the microenvironment of the micelles and the size of the micelles was done using ¹H NMR and dynamic light scattering measurements.     

超亲水防雾表面研究进展

透明玻璃和树脂材料应用广泛，是未来世界重要的构成元素。但这些材料表面常易发生水蒸气凝结起雾现象，不但降低了材料本身的透明度，影响相关产品的使用，还会给设备的运行安全带来隐患。因此，如何防雾逐渐引起研究人员和产业届的关注。常见的防雾技术有自动擦拭、热力防雾、表面涂层等。其中，具有主动防雾性能的超亲水表面涂层技术在施工简便性、持续防护性及运行维护成本的经济性等方面具有独特优势，是最有发展潜力的防雾技术。详细介绍了超亲水防雾表面的设计和制造技术的最新进展，从起雾现象的机制出发，介绍了水滴的形核和生长，并由此引出超亲水表面的防雾机理。分类介绍了由不同制备方法所得到的超亲水防雾表面，重点综述了近年来超亲水防雾涂层技术的研究进展，包括有机超亲水涂层、无机超亲水涂层与有机无机杂化超亲水涂层。针对各种形式的超亲水涂层技术，分别从涂层的亲水性、防雾性、耐久性及制备膜层的结构与性能之间的关系等方面进行了归纳。最后，根据超亲水防雾表面在不同领域的实际应用，对其未来的发展进行了展望。     

铱磷光配合物Ir(dfppy)2(phbudio)的合成及表征

以氯桥二聚体[Ir(dfppy)2(μ-Cl2)]2、1-苯基-1,3-丁二酮为原料合成了一种铱磷光配合物Ir(dfppy)2(phbudio)，产率86.0%，并通过元素分析、核磁共振谱、质谱和红外光谱表征确认了目标产物的化学结构。通过紫外-可见吸收以及荧光光谱对其光物理性质进行测试，其常温最大发射位于522 nm处，显示发射强烈的绿光，初步推测该铱磷光配合物发射可能来自金属铱到环金属配体和辅助配体的电荷转移(MLCT)跃迁。