刚果红分子印迹聚合物纳米微球的合成及吸附性能

本研究以刚果红为模板分子,α-甲基丙烯酸(MAA)为功能单体,二甲基丙烯酸乙二醇酯(EGDMA)为交联剂,乙腈为致孔剂,2,2-偶氮二异丁腈(AIBN)为引发剂,采用沉淀聚合法制备了刚果红分子印迹聚合物纳米微球(MIP).通过扫描、透射电镜对聚合物的结构和形貌进行了表征,结果显示制备的MIP微球的粒径在90 nm左右,粒径较为均匀.利用氮气吸附脱附实验测定了聚合物颗粒的比表面积和孔容.并对诸多吸附影响因素以及分子印迹聚合物的吸附能力、选择性和重复利用率进行了分析.结果表明,MIP对刚果红表现出较好的选择性识别能力,可多次循环使用,能用于染料废水中刚果红的选择性吸附.     

Tuning the catalytic selectivity in electrochemical CO2 reduction on copper oxide-derived nanomaterials

Electrochemical conversion of CO₂ to hydrocarbons can relieve both environmental and energy stresses. However, electrocatalysts for this reaction usually suffer from a poor product selectivity and a large overpotential. Here we report that tunable catalytic selectivity for hydrocarbon formation could be achieved on Cu nanomaterials with different morphologies. By tuning the electrochemical parameters, either Cu oxide nanowires or nanoneedles were fabricated and then electrochemically reduced to the corresponding Cu nanomaterials. The Cu nanowires preferred the formation of C₂H₄, while the Cu nanoneedles favored the production of more CH₄, rather than C₂H₄. Our work provides a facile synthetic strategy for preparing Cu-based nanomaterials to achieve selective CO₂ reduction.     

掺入CO催化活化CO2加氢合成甲醇的研究

用ＴＰＤ,ＴＰＳＲ－ＭＳ活性评价等方法,用Ｃｕ－Ｚｎ－Ａｌ催化剂,对ＣＯ２加氢合成甲醇的原料气掺入适量ＣＯ２进行了研究。结果表明ＣＯ２能占据催化剂表面部分ＣＯ２的吸附位,能抑制ＣＯ２加氢的逆水汽变换反应和促进甲醇合成,从而大大提高了ＣＯ２加事成甲醇的选择性和收率。     

几种耕作土壤钾交换特性的研究

本文研究了三组不同粘土矿物组成的耕作土壤钾素的交换特性,结果表明,供试土壤的钾交换选择性系数(K_c)与交换性钾比率(EPR)呈极显著的负相关,相关系数变化于-0.86至-0.95之间,且K_c因EPR的增加而趋于恒值。以伊利石、蛭石占优势的第一组土壤和以伊利石为主、高岭石为次的第二组土壤的K_c趋于恒值时的EPR明显高于以高岭石为主、伊利石为次的第三组土壤。三组土壤的钾吸附比率(PAR)与EPR均呈极显著的正相关,相关系数变化于0.94至0.98之间。土壤钾交换选择性的强弱因粘土矿物组成、粘粒含量和初始交换性钾饱和度的不同而表现出如下趋势:第一组土壤>第二组土壤>第三组土壤。     

脉冲放电协同Ag改性Mn-TiO2/分子筛催化剂去除甲醛

为进一步提高Mn-TiO2/分子筛催化剂和等离子体协同的催化活性,增加CO2选择性,减少O3产量。以5A分子筛为催化剂载体,采用浸渍法并利用Ag改性制备了Ag-Mn-TiO2/分子筛催化剂,并运用XRD、SEM、EDS和FT-IR等技术对催化剂进行了表征。在针-板式高压脉冲反应器中研究了Ag的负载量与焙烧温度对Ag-Mn-TiO2/分子筛催化剂的催化活性、CO2选择性和O3的产量的影响。结果表明：掺杂Ag后,促进Mn价态向+4价转变,提高了Mn-TiO2/分子筛催化剂活性;焙烧温度为500℃时,Ag和Mn在分子筛上分布均匀,有利于Ag和Mn氧化物晶粒成长。当脉冲电压20 kV,Ag负载量为4%时,Ag-Mn-TiO2/分子筛催化剂的甲醛去除率达到97.6%,O3浓度为99.4 mg·m-3,CO2选择性为50.2%。     

CO2催化转化催化剂研究现状

将CO₂通过催化反应转化为甲烷、甲醇、一氧化碳、甲酸、低碳烯烃和芳香烃等有价值化工原料是实现碳达峰和碳中和的重要手段。催化剂是转化过程的决定因素之一,开发高转化率和高选择性的催化剂仍是当前CO₂催化转化研究的重点内容。目前,采用的催化剂主要为贵金属催化剂和部分过渡态金属催化剂,同时部分非金属催化剂、新型催化剂和本体催化剂也具有良好的催化活性。转化产物分子结构的复杂化和非均相化程度越高,则CO₂催化转化的转化率和选择性越低。催化反应以热催化和光催化为主,反应条件的差异导致不同催化剂的性能可比性较差。因此,除开发高效催化剂外,建立规范化的CO₂催化转化评价方法也是未来研究的重点。

     

Selectivity in Mammalian Extinction Risk and Threat Types: a New Measure of Phylogenetic Signal Strength in Binary Traits

Abstract: The strength of phylogenetic signal in extinction risk can give insight into the mechanisms behind species’ declines. Nevertheless, no existing measure of phylogenetic pattern in a binary trait, such as extinction‐risk status, measures signal strength in a way that can be compared among data sets. We developed a new measure for phylogenetic signal of binary traits, D, which simulations show gives robust results with data sets of more than 50 species, even when the proportion of threatened species is low. We applied D to the red‐list status of British birds and the world's mammals and found that the threat status for both groups exhibited moderately strong phylogenetic clumping. We also tested the hypothesis that the phylogenetic pattern of species threatened by harvesting will be more strongly clumped than for those species threatened by either habitat loss or invasive species because the life‐history traits mediating the effects of harvesting show strong evolutionary pattern. For mammals, our results supported our hypothesis; there was significant but weaker phylogenetic signal in the risk caused by the other two drivers (habitat loss and invasive species). We conclude that D is likely to be a useful measure of the strength of phylogenetic pattern in many binary traits.     

Stereoselective metabolic disruption of cypermethrin by remolding gut homeostasis in rat

Cypermethrin (CYP), a prototypical synthetic pyrethroid, reportedly causes metabolic disruption, while its stereoselective impact remains elusive. This study initially revealed that only α-CYP caused significant weight loss at 8.5 mg/(kg•day) in rats. All three CYP isomers caused the accumulation of hepatic glycogen, and hyperlipemia phenotype as the increment of total triglyceride. Rats treated with α-CYP had markedly high blood glucose levels and homeostasis model assessment of insulin resistance index. The systematic inflammation of θ-CYP group rats was evidenced by high lipopolysaccharide-binding protein levels and abnormalities of leukocytes indices. By examining the gut microbiome, we found that α-CYP-treated rats had low contents of Firmicutes and high levels of Verrucomicrobia while Elusimicrobia was enriched in the β-CYP group. The increasing alpha diversity in the θ-CYP group may be due to the dominance of pathogenic bacteria and the increase of probiotics to counteract adverse effects. Exclusively, the α-CYP group enriched total short-chain fatty acids (SCFAs), whereas most SCFAs depleted in the θ-CYP group. The correlation analysis further found Firmicutes, an energy storage modulator, was positive to body weight (BW), while SCFAs exerted the opposite, confirming the low BW in α-CYP. Blood glucose that correlated well with SCFAs and Verrucomicrobia can be accounted for the discrepancy between α-CYP and θ-CYP. Overall, the three isomers exerted stereoselective glycolipid disruption in rats, and gut homeostasis acted as vital indicators.     

g-C3N4/RGO的制备、光催化降解性能及其降解机理

尿素固相反应得到石墨相氮化碳(g-C₃N₄),石墨(G)被氧化制得氧化石墨(GO),GO被还原制得石墨烯(RGO),通过3种复合方法分别制得g-C₃N₄/RGO材料.通过对污染物亚甲基蓝、罗丹明B和甲基橙的降解,考察了g-C₃N₄与GO不同复合比9.7:1、9.3:1、9:1、8:1和6.7:1对光催化剂g-C₃N₄/RGO光催化性能的影响.同时考察了复合物对污染物的选择性降解.用X-射线衍射谱(XRD)和傅里叶变换红外光谱(FT-IR)对催化剂的结构性质进行了表征.结果表明,g-C₃N₄与GO混合-水合肼还原-高温固相反应法制备的g-C₃N₄/RGO,时间最短,产量较高,对罗丹明B的降解效果最佳,说明该方法较好.另外,当g-C₃N₄与GO的质量比为9.7:1时,制备的g-C₃N₄/RGO降解效果最佳.还有,该复合材料对亚甲基蓝的降解效果最佳,罗丹明B次之,甲基橙最差.机理研究结果表明超氧自由基在光催化过程中起主导作用,羟基自由基起次要作用.