介质阻挡放电等离子体对亚甲基蓝的降解

研究了介质阻挡放电等离子体降解亚甲基蓝溶液过程。考察了放电电压、亚甲基蓝溶液初始浓度、初始pH值对降解率的影响和降解过程中亚甲基蓝溶液pH值的变化。结果表明:100mg/L的亚甲基蓝溶液在放电频率为10.5kHz,电压为22kV,pH值为5.68的实验条件下,降解40min后,亚甲基蓝降解率为99.8%。对降解产物进行气质联用分析,亚甲基蓝降解产物中存在甲苯、乙烷基环戊烷、苯并噻唑等物质。     

Clockwork blue: on the evolution of non-image-forming retinal photoreceptors in marine and terrestrial vertebrates

This paper presents a hypothesis that could explain why blue light appears to dominate non-image-forming (NIF) ocular photoreception in marine as well as terrestrial vertebrates. Indeed, there is more and more evidence suggesting that 'novel' retinal photoreceptors, which are sensitive to blue light and were only discovered in the 1990s, could be a feature shared by all vertebrates. In our view, blue light photoreception evolved and persisted as NIF photoreception because it has been useful in the colonisation of extensive photo-dependent oceanic habitats and facilitated the move of vertebrates from an aquatic to a terrestrial environment. Because the available scattered evidence is compatible with the validity of our hypothesis, we hope that our rationale will be followed up. Indeed, it (1) involves testable predictions, (2) provides plausible explanations for previous observations, (3) unites phenomena not previously considered related to one another and (4) suggests tests that have not been carried out before. Overall, our approach not only embraces cross-disciplinary links; it, moreover, serves as a reminder of an all-embracing evolutionary history, especially with regard to a ubiquitous photoreceptive 'clockwork-blue' in marine and terrestrial vertebrates.     

Physicochemical and physiological basis of dichromatic colour

Out of three perceptual characteristics of the colour of any substance, the hue depends mostly on the spectral properties of a substance, while the brightness and saturation depend also on the concentration of a substance and its thickness. Here, we report that evident change of the hue of the colour (i.e., from green to red) is due to a change in concentration or the thickness of a layer in some exceptional substances such as pumpkin seed oil or an aqueous solution of bromophenol blue. In some regions of Central Europe, salad dressing is made preferably with the pumpkin seed oil, which has a strong characteristic nut-like taste and remarkable properties of the colour: it appears red in a bottle, but green when served as a salad dressing. The colour of the pumpkin seed oil was previously described as brownish yellow, dark green, dark green to red ochre or dark reddish brown to light yellow green. We elucidated the physicochemical and physiological basis of such dichromatism by Beer-Lambert law and by the characteristics of human colour perception. Our concept was corroborated by the outcome of calculations of colour from spectral properties using colour matching functions. We found that dichromatism is observed if the absorption spectrum of any substance has at least two local minima: one wide but shallow and one narrow but deep local minimum.     

绿色、蓝色和蓝-绿屋顶径流水质特征

屋顶占据大量城市不透水面,实施生态屋顶建设,有利于缓解城市化造成的生态和环境问题.在北京市区搭建不同类型生态屋顶(绿色屋顶、蓝色屋顶和蓝-绿屋顶),基于对2019年雨季降雨特征、各类生态屋顶径流量以及径流中营养盐和重金属浓度的监测,计算不同生态屋顶径流污染负荷和径流水质指数(RQI),定量对比分析不同类型生态屋顶径流的综合水质差异.结果表明,在2019年雨季,各生态屋顶均表现出良好的雨水滞留能力,平均径流削减率在75.7%～78.9%之间,且不同生态屋顶的径流削减率无显著差异(P>0.05);相较雨水,各生态屋顶均为NH⁺₄-N、 DZn和DCd的汇,累积负荷削减率分别在63.8%～96.4%、68.6%～90.7%和39.8%～54.5%之间,但均为NO^-₃-N、 DCr、 DFe和DNi的释放源;蓝色屋顶是DCu的汇(累积负荷削减率为21.9%),但对雨水径流中PO^3-₄-P的累积负荷无明显影响,而绿色和蓝-绿屋顶均为PO^3-     

秸秆及磁性秸秆吸附剂对废水中亚甲基蓝的去除行为及机理

以水稻秸秆(RS)为对象,通过化学沉淀法负载Fe_3O_4以制备秸秆负铁(RS-Fe)复合材料.同时,采用MBET、SEM、FTIR、XRD、XPS、VSM技术对RS、RS-Fe进行表征,研究了秸秆及复合材料对溶液中亚甲基蓝(MB)的去除效果,考察了固液比、溶液初始pH值对亚甲基蓝吸附效果的影响,并结合吸附动力学、吸附等温线、仪器表征及官能团封闭实验探究其作用机理.结果表明,吸附剂投加量为4.0 g·L~(-1)较合适;pH在3.0～11.0内,RS对MB去除率均在90%以上,碱性条件下有利于亚甲基蓝的高效去除.RS和RS-Fe对亚甲基蓝的吸附符合拟二级动力学模型.RS对亚甲基蓝的去除符合Langmuir模型,而RS-Fe对亚甲基蓝的去除更适合用Freundlich模型描述.FTIR、XPS和官能团封闭实验分析表明,秸秆表面官能团能在亚甲基蓝吸附过程中发挥重要作用,其中,羧基和氨基更为重要.秸秆对亚甲基蓝的吸附机理包括静电作用、氢键和π-π作用.Fe_3O_4的引入减少了秸秆官能团数量,降低了对亚甲基蓝的吸附量,但能实现快速固液分离.因此,RS具有作为亚甲基蓝染料废水吸附剂的潜力.负铁RS有利于提升固液分离效果.     

磁性壳聚糖的制备及处理亚甲基蓝废水

以戊二醛为交联剂,Fe₃O₄为磁核制备磁性壳聚糖,探究了其去除废水中亚甲基蓝的性能,以及吸附动力学、吸附等温线、吸附热力学特征.结果表明,在磁性壳聚糖投加量为0.5g/L、pH=10、反应时间为60min的条件下,对亚甲基蓝的去除率和吸附容量分别达到97.6%和39.0mg/g,远高于天然壳聚糖的59.8%和23.9mg/g.磁性壳聚糖对亚甲基蓝的吸附过程符合准二级反应动力学方程（R²=0.99902）和Langmuir等温线方程（R²=0.99961）,吸附过程是热力学自发过程,吸附反应是放热反应.     

铁改进型蓝藻生物炭的制备及对地表水中磷的协同吸附机制

为缓解水体富营养化以及蓝藻堆积问题,采用经过聚合硫酸铁(PFS)脱水后的蓝藻制备生物炭吸附水体中的磷酸盐,其中生物炭经过水蒸气活化调节孔隙结构.通过响应面法对蓝藻生物炭的制备条件进行优化.当PFS投加量为458 mg·L^-1、碳化温度为433℃和生物炭前体物与水蒸气的质量比为1∶11.选取不加PFS生物炭(F₀H₁₁-433)与加PFS生物炭(F₄₅₈H₁₁-43)进行X射线衍射(XRD)、傅里叶红外光谱(FTIR)、 Zeta电位和拉曼光谱(Raman)表征,来研究蓝藻生物炭与PFS对磷酸盐的去除是否具有协同效应.结果表明,与F₀H₁₁-433相比,F₄₅₈H₁₁-433表面出现铁氧化物,零电荷点(pH_pzc)从4.41提高到6.19,生物炭的无序、缺陷程度得到提高.准二级动力学模型和Langmuir模型适用于描述F₄₅₈H₁₁     

山茶籽粉吸附亚甲基蓝的性能研究

为研究山茶籽粉对亚甲基蓝的吸附行为,对不同温度下(298、303、308、313、318K)的吸附数据分别用Langmuir、Freundlich和Dubinin-Radushkevish模式进行拟合,用伪一级动力学方程和伪二级动力学方程描述山茶籽粉对亚甲基蓝的吸附动力学过程,并计算了Gibbs自由能变(ΔGθ)、焓变(ΔHθ)和熵变(ΔSθ)等热力学函数.结果表明,山茶籽粉对亚甲基蓝的吸附能力随着温度的升高而降低;Langmuir方程更适合描述其吸附行为.Gibbs自由能变(ΔGθ)、焓变("Hθ)和熵变(ΔSθ)均小于零,说明此吸附过程是自发进行的、放热的、趋于有序的吸附过程.伪二级动力学方程更适用于描述山茶籽粉对亚甲基蓝的吸附动力学过程.     

改性碳纳米管原始样品吸附亚甲基蓝的性能研究

利用直接制备的碳纳米管原始样品作为染料亚甲基蓝的吸附剂,采用次氯酸钠溶液对于碳纳米管原始样品进行表面修饰改性,改性处理后碳纳米管对亚甲基蓝吸附性较好,本工艺简单有效,所获得的吸附剂具有磁性,吸附过后用磁铁易于达到固液分离的效果.吸附性能结果表明:本吸附剂对水溶液中亚甲基蓝的吸附在60 min基本达到平衡,吸附过程符合准二级动力学模型(R2>0.99).改性后的磁性碳纳米管吸附亚甲基蓝的平衡吸附量qe与亚甲基蓝溶液的平衡浓度Ce的关系满足Langmuir(R2>0.99)、Freundlich(R2>0.91)以及Dubinin-Radushkevich(D-R)(R2>0.92)等温吸附模型.通过Langmuir模型计算可知改性磁性碳纳米管对亚甲基蓝的最大吸附容量为101.6 mg.g-1,由D-R模型计算结果可以推断,次氯酸钠改性后的磁性碳纳米管对水溶液中亚甲基蓝的吸附机理以化学吸附为主.     

Y型分子筛负载铁催化剂对活性艳蓝KN-R脱色的研究

利用Y型分子筛负载铁催化剂对活性艳蓝KN-R的脱色进行研究,探讨了催化剂的制备方法、铁负载量、投加剂量、反应体系pH值以及焙烧温度对活性艳蓝KN-R催化脱色效率的影响,并考察了催化剂的重复利用性能.结果表明:离子交换法制得的Y型分子筛负载铁催化剂表现出较佳的染料脱色性能.在pH＜3.0,H2O2投加剂量为50.0 mmol·l-1,催化剂投加剂量为4.0g·l-1的条件下,对初始浓度为250mg·l-1的KN-R模拟染料废水,30 min之内脱色率达95%以上.采用有机酸络合铁作为铁源制得的Y型分子筛负载铁催化剂的催化活性大幅增强,但催化剂稳定性降低.铁负载量影响染料的脱色反应活性,过量负载会导致染料脱色效率降低;同样,适度增大催化剂用量可促进染料脱色效率,但过量投加不利于染料的脱色.pH＜3.0为该Y型分子筛负载铁催化剂的适用pH条件;催化剂重复利用三次后,1h内对活性艳蓝KN-R的脱色率仍可达95%以上.