Study of H2O adsorption on sulfides surfaces and thermokinetic analysis

Adsorption of water on mineral surfaces was studied using density functional theory and microcalorimetry technique. The calculation results show that galena and molybdenite are hydrophobic, while pyrite and sphalerite is hydrophilic. Thermokinetic analysis shows that the heat of adsorption is in decreasing order of pyrite, sphalerite, galena and molybdenite, which is in good agreement with the calculation results. The adsorption kinetics parameters of hydrophobic galena and molybdenite surfaces are close, while those of hydrophilic pyrite and sphalerite surfaces are very different. The adsorption rate of water on the sphalerite surface is larger than that of water on the pyrite surface.     

Designed metal–organic framework based on metal–organic polyhedron: Drug delivery

A new metal–organic framework having formula {[NH₂(CH₃)][Cu₆(L)₃(OAc)(H₂O)₄]·xsolvent} (H4L = 3,5-bis(isophthalic acid)-1H-1,2,4-triazole) (1) was synthesized, in which two types of polyhedral cages and one-dimensional channels coexist. The incorporation of the drug 5-fluorouracil (5-FU) into the desolvated 1 was around 24.9 wt% per gram of dehydrated 1. 5-FU is released in a controlled and progressive fashion with 98% of the drug released after 120 h at PBS. The result from this work provides a new avenue for MOF to be used as potential drug delivery.     

Effects of neutron irradiation on polymer matrix composites at 5 K and at room temperature: II. Degradation of mechanical properties

Neutron irradiation with a low flux of accompanying γ-rays in the Intense Pulsed Neutron Source was carried out at 5 K and at room temperature on four kinds of polymer matrix composites (filler: E-glass or carbon fiber cloth; matrix: epoxy or polyimide resin). The specimen irradiated at 5 K was warmed up to room temperature before the mechanical test was performed at 77 K. The Young's modulus of these composites scarcely decreases even when a total neutron fluence is 3.0 × 10¹⁸n/cm² (2.1 × 10¹⁸n/cm² for E > 0.1 MeV) for the 5 K irradiation and 1.6 × 10¹⁹n/cm² (8.0 f 10¹⁸ n/cm² for E > 0.1 MeV) for the room-temperature irradiation. The ultimate strength, however, decreases significantly at this neutron fluence for all the composites except the carbon/epoxy composite whose initial strength is comparatively low. Comparison of this result with that obtained for ⁶⁰Co γ-ray irradiation demonstrates that the radiation sensitivity of the glass/epoxy and glass/polyimide composites is 1.8–2.6 times higher towards neutrons than γ-rays. As to the irradiation temperature of 5 K and room temperature, no significant influence on the degradation efficiency of the composite strength is observed under the present conditions of mechanical test.     

N-(歧化松香基)丙烯酰胺聚合物的合成研究

以歧化松香胺、丙烯酸为原料,在催化剂五氧化二磷的作用下先合成N-(歧化松香基)丙烯酰胺;然后在催化剂三氯化铝的作用下催化聚合得到N-(歧化松香基)丙烯酰胺聚合物,通过紫外及红外光谱分析其结构,测定了N-(歧化松香基)丙烯酰胺聚合物的溶解度、分子量、微孔结构及热稳定性,并讨论了制备N-(歧化松香基)丙烯酰胺、N-(歧化松香基)丙烯酰胺聚合物的合成条件.     

水热碳化法制备淀粉碳化物/海泡石(St-Sep)复合材料的优化

以木薯淀粉和天然海泡石为原材料,制备了新型淀粉碳化物/海泡石(St-Sep)复合材料,用真空冷冻干燥器干燥样品,并利用响应面法优化了制备工艺.利用水热碳化法制备了St-Sep复合材料,并利用X射线衍射仪(XRD)和傅里叶红外变换光谱仪(FTIR)对材料的结构进行表征,证明了St-Sep的成功合成.进一步用扫描电镜(SEM)、比表面积(BET)测定对样品形貌和比表面进行表征.以亚甲基蓝作为吸附质,响应面法优化了材料的制备工艺.实验结果表明,复合材料制备最优工艺条件为:淀粉与海泡石质量比为2.5∶1.0、碳化时间为16h;碳化温度为200℃,对亚甲基蓝的最优吸附量为40.6084 mg/g;各因素对复合材料吸附亚甲基蓝性能的影响顺序为:淀粉与海泡石质量比＞碳化温度＞碳化时间.     

丙烯海松酸聚乙二醇酯的合成及聚集行为

以松香和丙烯酸为单体合成了丙烯海松酸,利用气相色谱-质谱联用技术（GC-MS）对合成的丙烯海松酸进行了表征。以丙烯海松酸和聚乙二醇2000为单体采用条件温和的steglich酯化法合成了两亲性的丙烯海松酸聚乙二醇酯,并应用红外（FT-IR）、凝胶渗透色谱（GPC）和热重（TG）研究了该物质的结构和性能。结果表明：丙烯海松酸聚乙二醇酯数均相对分子质量为4 700,多分散系数为1.2,分解温度在308~410℃范围内。采用表面张力和芘稳态荧光法测定了该物质的临界胶束质量浓度（CMC）,其CMC为1 g/L。用共振光散射（RLS）、动态光散射（DLS）和扫描电镜（SEM）法研究了丙烯海松酸聚乙二醇酯水溶液的聚集行为,结果表明：1 g/L的丙烯海松酸聚乙二醇酯水溶液在高于聚集温度74℃时胶束聚集,随着溶液的质量浓度由1 g/L增加到1.5 g/L时,聚集温度由74℃降低到65℃;1 g/L丙烯海松酸聚乙二醇酯水溶液的温度由25℃升高到85℃时,水合粒子平均直径（D_h）由295 nm增加到1 056 nm。     

微波和超声波辅助提取穿心莲内酯

用正交法对微波和超声波辅助提取穿心莲内酯的工艺条件进行优化。微波辅助法提取穿心莲内酯的最佳工艺条件为温度40℃、提取溶剂为体积分数75%的乙醇、提取时间8 min;超声波辅助法提取穿心莲内酯的最佳工艺条件是提取溶剂为体积分数75%的乙醇,超声效率40%、超声时间50 min。微波提取法的平均回收率为99.9%,RSD为0.31%;超声波提取法的平均回收率为100.5%,RSD为0.21%。与超声波提取法相比,微波提取法提取时间较短,提取得率较高。     

Assessment of the catalytic effect of various biomass ashes on CO2 gasification of tire char

The aim of this study was to determine the effect of various biomass ashes, comprising catalytically active components, on tire char reactivity during the CO₂ gasification process. Ashes from the combustion of corn cobs, beet pulp, sunflower husks and beech chips were selected for the research. Moreover, industrial fly ash from a coal-fired power plant was used as a reference. The tire char-ash blends with different ash contents (0–15 wt%) were gasified in the CO₂ atmosphere under non-isothermal conditions using dynTHERM Rubotherm thermobalance. Based on the n-order Coats and Redfern method, gasification reactivity indicators and kinetics parameters were calculated. The results showed that the addition of biomass ashes enhanced reactivity of tire char, and the magnitude of these changes depended on both the quantity and type of the additive. With the increase in the amount of added biomass ashes, the catalytic effect increased, and their efficiency can be ranked as follows: sunflower husk ash > corn cobs ash ≅ beet pulp ash > beech chips ash. In turn, reference fly ash from a power plant slightly affected the CO₂ gasification of tire char, regardless of its amount. Moreover, a statistically significant correlation between the reactivity indicator and the amount of K₂O, MgO and P₂O₅ in ashes analysed has been proved (reactivity indicator improved with an increase in these components amount). The performed analysis provides valuable information regarding the composition of catalysts characterised by high catalytic activity in the tire char gasification process.     

Computational simulation of adsorption and thermodynamic study of xanthate,dithiophosphate and dithiocarbamate on galena and pyrite surfaces

Computer modeling and the microcalorimetry method were employed to investigate the adsorption of xanthate, dithiophosphate (DTP) and dithiocarbamate (DTC) on the galena and pyrite surfaces. The calculated results show that the pyrite surface undergoes greater relaxation than galena, while galena has a more electronegative surface than pyrite. The pyrite Fe atom is more active than the galena Pb atom. The simulations of adsorption show that the adsorbates coordinate mainly to the surfaces through interaction between their S atoms with the surface Pb or Fe atoms. The analysis of the density of states (DOSs) suggests that the adsorption of xanthate on the pyrite surface is stronger than that on the galena surface, while that of DTP and DTC are stronger on the galena surface than on the pyrite surface.The heat of adsorption and kinetics parameters of DTC and DTP at the galena and pyrite surfaces differ greatly, suggesting that DTC and DTP exhibit good selectivity in the separation of pyrite and galena, while these two parameters for xanthate at the two minerals differ little, indicating the poor selectivity of xanthate.     

甲醛和铁粉协同还原浸出低品位氧化锰矿

以甲醛和铁粉为还原剂在硫酸溶液中协同还原氧化锰矿,考察了还原剂用量、硫酸体积分数、浸出时间、浸出温度、液固比和搅拌速率对锰浸出率、浸出液中铁和甲酸的质量浓度的影响,并用响应面法设计优化试验。结果表明,在硫酸的体积分数为15%、甲醛用量为理论量的90%、甲醛和铁的摩尔比为2、二者浸出时间之比为2、总浸出时间2.93h、浸出温度85℃、液固比6、转速150r/min的条件下,锰浸出率达98.04%,浸出液中铁和甲酸的质量浓度分别为13.96mg/mL、1.40mg/mL。