可见光下氮掺杂二氧化钛对巯基苯并噻唑的降解

光降解反应中为了有效地利用可见光,以氨水为氮源,采用溶胶凝胶法在温和条件下制备出黄色氮掺杂二氧化钛。分别采用XRD、TEM、XPS和UV-Vis漫反射光谱对样品进行了表征。结果表明,所制备的样品均为锐钛矿相,晶粒随N/Ti配比的增加而增大;氮掺杂进入二氧化钛晶格中使可见光吸收增强。为控制水处理过程中的气味问题,以巯基苯并噻唑为探针,考察了氮掺杂二氧化钛的可见光活性。结果显示氮掺杂二氧化钛在可见光照射下可使巯基苯并噻唑的降解率为商用二氧化钛DegussaP-25的3倍。此外,存在一个最佳N/Ti配比显示出最高的可见光活性。     

蛋氨酸为硫源的硫掺杂二氧化钛的光催化活性

为改善二氧化钛的可见光催化活性,以蛋氨酸为硫源,在温和条件下采用溶胶-凝胶法制备了硫掺杂二氧化钛粉末。采用XRD、TEM、UV-Vis漫反射吸收光谱和XPS等方法对制备的样品进行表征,以甲基橙的光降解效果考察其可见光催化活性。结果显示：350~500℃所制备的硫掺杂二氧化钛均为锐钛矿相,600℃出现混晶,且硫的掺杂一定程度的抑制了粒径的增长和晶相的转变;硫以阳离子形式进入二氧化钛晶格中,引起光催化剂在可见光区的光吸收;掺杂样品表现出较好的可见光催化活性,且随煅烧温度的增加,催化活性逐渐降低。正交试验得出优化条件为：S/Ti物质的量配比为1.6%,煅烧温度为450℃,煅烧时间为3 h。     

离子交换树脂对甲基叔丁基醚的催化水解

研究了D008离子交换树脂对甲基叔丁基醚(MTBE)的吸附作用,以及H-D008树脂对MTBE水解的催化作用,结果表明,Na-D008及H-D008树脂对MTBE都具有较强的吸附作用,吸附等温线呈直线型.H-D008树脂催化MTBE的水解反应符合一级反应动力学.初始浓度增大,表观一级速率常数基本不变;温度升高,表观一级速率常数增大,当温度为25℃,30℃和35℃时,表观一级速率常数分别为0.067 d-1,0.216 d-1和0.343 d-1.H-D008催化水解MTBE反应的活化能为124.8 kJ·mol-1.     

钒-氮共掺杂TiO2的合成、表征及光催化性能

以偏钒酸铵作为钒源、二乙醇胺作为氮源,采用溶胶-凝胶法合成了钒-氮共掺杂TiO2.通过XRD、UV-Vis、TEM、XPS、BET等表征手段,对光催化剂的晶体结构及形貌、紫外可见光响应特性、比表面积、表面元素及存在形式进行分析,探讨钒氮共掺杂TiO2的影响机制.以苯酚为污染物,评价其在紫外光及可见光下的光催化活性.结果显示,所合成的光催化剂均为锐钛矿,钒氮共掺杂能够增大其比表面积,并使光吸收范围拓展至可见光区,N以O—Ti—N、Ti—O—N结构存在于钒氮共掺杂TiO2中,V以V5+的形式存在,钒-氮共掺杂TiO2在紫外光下对苯酚降解速率是TiO2的3.18倍,在可见光下对苯酚的降解速率为TiO2的2.56倍,重复使用7次后,钒-氮共掺杂TiO2对苯酚的降解率仍可以达到99%以上.     

氮掺杂石墨烯高效移除水中4-氯苯酚

采用水热法分别制备了未掺氮和氮掺杂还原氧化石墨烯(N-RGO),以此作为催化性吸附剂,通过活化过硫酸盐(PS)在水相中同时吸附和氧化降解对氯苯酚(4-CP).氮的引入不仅增强石墨烯吸附性能,而且提高其活化PS能力.通过比较未掺氮RGO与N-RGO对初始浓度为40 mg·L~(-1)的4-CP的吸附和降解速率发现,吸附移除率从21.6%增加至39.4%,对应的降解速率常数k值也从0.003 min~(-1)增加至0.13 min~(-1).随后研究了N掺杂量、PS初始浓度、N-RGO用量及反应温度对吸附降解过程的影响.结果表明,当氨水浓度为14000 mg·L~(-1)时所制备的N-RGO的性能最优.在PS初始浓度为540 mg·L~(-1),催化剂用量为120 mg·L~(-1),pH值为6.6,温度为25℃时,25 min对40 mg·L~(-1)的4-CP的总移除率达93%以上.通过稳定性测试显示N-RGO经4次循环使用后仍具有较高性能,该体系在污水处理领域具有良好应用前景.     

黄河中下游沉积物对磷酸盐的吸附动力学研究

研究了黄河中下游10个不同表层沉积物在黄河水体中对磷酸盐（P）的吸附动力学及其影响因素和吸附机理。结果表明：（1）不同黄河沉积物对P的吸附能力各不相同,但吸附量随时间的变化具有相同的变化趋势,吸附速率均在前8h内较快,以后逐渐趋缓,在48h时基本达到吸附平衡。不同黄河沉积物对P的吸附量均随P初始质量浓度的增加而增大,随沉积物含量增大而减小;（2）不同沉积物在不同P初始质量浓度下对P的吸附动力学均符合Lagergren二级吸附动力学模型及Weber-Morris扩散方程,求得二级吸附速率常数和扩散速率常数分别在11.9866～157.55g·mg^-1·h^-1和0.0005～0.0119mg·g^-1·h^-1/2之间,吸附过程由P在沉积物内扩散控制。     

黄河上游沉积物对磷酸盐的吸附动力学研究

研究了黄河上游10个不同表层沉积物在黄河水体中对磷酸盐（P）的吸附动力学及其影响因素和吸附机理。结果表明：不同黄河沉积物对P的吸附能力各不相同,但吸附量随时间的变化具有相同的趋势,吸附速率均在前8 h内较快,以后逐渐趋缓,在48 h时基本达到吸附平衡。不同黄河沉积物对P的吸附量均随P初始质量浓度的增加而增大,随沉积物质量浓度增大而减小,且也受水体pH值的影响,在pH为6.0~9.0范围内吸附量比较大。不同沉积物在不同P起始质量浓度下对P的吸附动力学均符合Lagergren二级吸附动力学模型及Weber–Morris扩散方程,求得二级吸附速率常数和扩散速率常数分别在10.85~229.29 g.mg-1.h-1和0.7×10-3~5.2×10-3 mg.g-1？h-1/2）之间,吸附过程由P在沉积物内的扩散控制。     

漆酶修复土壤DDT污染的动力学研究

研究了漆酶在土壤灭菌与否以及在不同施用剂量条件下对土壤DDT污染的修复动力学特征.结果表明,在土壤灭菌与否和不同施用剂量条件下,漆酶对DDT各组分及DDTs的降解率均随着时间的延长而不断提高,且在第15天之前提高迅速,到第15天之后至第25天基本上处于稳定状态.DDTs的降解过程符合拟表观一级动力学方程,非灭菌对照处理和灭菌对照处理之间,以及非灭菌加酶处理和灭菌加酶处理之间DDTs的降解速率常数分别相近,且加酶处理的降解速率常数明显高于对照处理.随着加酶量的增大,DDTs的降解速率常数也呈增大趋势,其中在加酶量为6 U·g-1土时其降解速率常数最大.     

NKY功能化树脂静态吸附混合染料的研究

探讨了NKY功能化树脂对混合染料(活性艳蓝：KN-R和活性艳橙K-GN)的静态吸附行为．结果表明：NKY树脂吸附单组分染料的能力大于其对混合染料的吸附，而且对混合体系中的染料有一定的选择性，吸附KN-R的速率较大．从动力学研究来看，NKY对混合染料的吸附速率其决定步骤是液膜扩散．等温曲线的结果显示，NKY对混合染料中每种组分的吸附行为同吸附单组分体系的类似，同时，随温度的升高，吸附速率常数增大，标准自由能变的绝对值增大。     

钛掺杂氧化铋紫外光催化降解水中全氟辛酸(PFOA)

通过水热法制备了Ti(Ⅳ)掺杂Bi_2O_3(BTO),采用扫描电镜(SEM)、X射线粉末衍射(XRD)、X射线光电子能谱(XPS)等技术对其形貌和结构进行表征,并考察了钛掺杂氧化铋光催化降解水中PFOA的降解效果,发现PFOA的降解符合一级反应动力学,其降解速率常数为-0.2 h~(-1),比商业用纳米二氧化钛P25提高了6.8倍.表征结果证明,BTO存在多孔结构,能够增加反应活性位点,提高光催化活性面积.同时,自由基捕获实验和中间产物分析表明,光生空穴对PFOA的断链分解起决定性作用;同时Bi—O—Ti表面基团吸附PFOA并弱化了C—F键,导致光生电子可自由移至C—F键上并实现还原脱氟;光生电子和空穴在功能上相互配合,实现了对PFOA的协同降解;PFOA的降解过程受还原性物质主导,通过C—C键的断裂生成短链全氟羧酸类物质.     

Concurrent adsorption and reduction of chromium(VI) to chromium(III) using nitrogen-doped porous carbon adsorbent derived from loofah sponge

• A high-efficiency N-doped porous carbon adsorbent for Cr(VI) was synthesized. • The maximum adsorption capacity of Cr(VI) reached up to 285.71 mg/g at 318K. • The potential mechanism for Cr(VI) adsorption by NHPC was put forward. • DFT analyzed the adsorption energy and interaction between NHPC and Cr(VI). To develop highly effective adsorbents for chromium removal, a nitrogen-doped biomass-derived carbon (NHPC) was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification. NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups (1.33 at%), specific surface area (1792.47 m²/g), and pore volume (1.18 cm³/g). NHPC exhibited a higher Cr(VI) adsorption affinity than the HPC (without nitrogen doping) or the pristine loofah sponge carbon (LSC) did. The influence of process parameters, including pH, dosage, time, temperature, and Cr(VI) concentration, on Cr(VI) adsorption by NHPC were evaluated. The Cr(VI) adsorption kinetics matched with the pseudo-second-order model (R²≥0.9983). The Cr(VI) adsorption isotherm was fitted with the Langmuir isotherm model, which indicated the maximum Cr(VI) adsorption capacities: 227.27, 238.10, and 285.71 mg/g at 298K, 308K, and 318K, respectively. The model analysis also indicated that adsorption of Cr(VI) on NHPC was a spontaneous, endothermal, and entropy-increasing process. The Cr(VI) adsorption process potentially involved mixed reductive and adsorbed mechanism. Furthermore, computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI) (−0.84 eV) was lower than that of HPC (−0.51 eV), suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).     

Visible light-assisted photocatalytic oxidation of organic pollutants using nitrogen-doped titania

An experimental research into the aqueous photocatalytic oxidation (PCO) of organic groundwater pollutants, methyl-tert-butyl ether (MTBE), tert-butyl alcohol, phenol, humic substances, 2-ethoxy ethanol and ethylene glycol was undertaken using visible light-sensitive nitrogen-doped titanium dioxide photocatalysts. Nitrogen-doped titania proved to be an effective photocatalyst for MTBE with its action comparable to and even surpassing that of Degussa P25. In contrast, with the other substances the photocatalysts showed negligible activity. This difference was explained by the poor adsorption properties of N-doped catalysts. The predominance of different PCO mechanisms dependent of the surface properties of N-TiO₂ catalysts was elucidated.     

酞菁锌改性介孔分子筛催化降解孔雀石绿

以介孔分子筛MCM-41为载体,采用浸渍法将1,4,8,11,15,18,22,25-八环戊氧基酞菁锌(α-CyOPcZn)负载到分子筛上得到了一种新型的催化剂CyOPcZn/MCM-41.并通过氮气吸附、红外光谱扫描及电镜扫描对催化剂的结构进行表征.考察了该催化剂的用量、H2O2浓度对孔雀石绿降解作用的影响.实验结果表明,在模拟可见光照射下,当催化剂用量0.6 g.L-1、H2O2浓度为0.1 mmol.L-1时,60 min后使0.1 mmol.L-1的孔雀石绿水溶液的脱色率达到98.6%,并呈现出一级反应的动力学特征,速率常数k为0.0891 min-1.催化剂重复使用3次后,脱色率可达96%以上.     

Selective photoreduction of acetonitrile to acetaldehyde in dilute aqueous solutions

Acetonitrile is a commonly used solvent in both industry and research. The treatment of acetonitrile wastes in dilute aqueous solutions with visible light offers advantages to chemical treatment and ultraviolet (UV) irradiation. This study presents the degradation of acetonitrile via a photoinduced electron transfer reaction in the presence of a photosensitizer (dye) and a sacrificial reductant under visible light. Acetonitrile photodegradation (photoreduction) was investigated utilizing a variety of sacrificial reductants and photosensitizers. Optimal results were observed in the presence of methylene green and tri-isopropanolamine with a decrease of acetonitrile in solution to 86% in 24 hours. The only photoreaction product observed was acetaldehyde and a plausible mechanism for the photochemical degradation of acetonitrile is proposed.     

杭锦2~#土复合吸附剂对磷的吸附动力学

通过静态试验考察杭锦2#土/聚合硫酸铝复合吸附剂对生活污水中磷酸根的吸附特性,研究吸附过程的动力学模型,并从动力学角度探讨其吸附机理。结果表明,在杭锦2#土/聚合硫酸铝复合吸附剂用量5 g.L-1、吸附时间60 min、废水pH值6.0、温度25℃、磷初始质量浓度小于16.72 mg.L-1条件下,磷酸根的去除率在96%以上;复合吸附剂对磷酸根的吸附动力学特征符合假二级方程,吸附速率在前10 min为内扩散控制,后期由膜扩散和内扩散共同控制,且膜扩散占主导地位;磷酸根的初始浓度越高,吸附质粒子的表观内扩散系数和表观传质系数越小;使用不同再生次数的再生吸附剂（添加量为5 g.L-1）处理16.72 mg.L-1含磷生活污水,随着再生次数的增加,吸附能力有所下降,但磷酸根的去除率均大于89%。     

Solar photocatalytic decomposition of two azo dyes on multi-walled carbon nanotubes (MWCNTs)/TiO<Subscript>2</Subscript> composites

Multi-walled carbon nanotubes (MWCNTs)/TiO₂ composite photocatalysts with high photoactivity were prepared by sol-gel process and further characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and UV-vis absorption spectra. Compared to pure TiO₂, the combination of MWCNTs with titania could cause a significant absorption shift toward the visible region. The photocatalytic performances of the MWCNTs/TiO₂ composite catalysts were evaluated for the decomposition of Reactive light yellow K-6G (K-6G) and Mordant black 7 (MB 7) azo dyes solution under solar light irradiation. The results showed that the addition of MWCNTs enhanced the adsorption and photocatalytic activity of TiO₂ for the degradation of azo dyes K-6G and MB 7. The effect of MWCNTs content, catalyst dosage, pH, and initial dye concentration were examined as operational parameters. The kinetics of photocatalytic degradation of two dyes was found to follow a pseudo-first-order rate law. The photocatalyst was used for seven cycles with photocatalytic degradation efficiency still higher than 98%. A plausible mechanism is also proposed and discussed on the basis of experimental results.     

不同来源太湖沉积物粒径分布及其对Cu的吸附特征

以不同来源的太湖沉积物为研究对象,利用Mastersizer 2000型激光粒度分析仪测定沉积物的粒度组成,利用筛析法和吸管法对不同来源沉积物进行分级,测定不同粒径沉积物中Cu含量及不同粒径沉积物对Cu2＋的饱和吸附量,研究沉积物对水溶液中Cu（Ⅱ）的吸附特性,从粒径分级和动力学角度探讨了太湖沉积物对Cu的吸附机理。结果表明：太湖沉积物粒径范围在0.002-0.1 mm,其颗粒组成以粉砂级与粘粒级为主,养殖区沉积物小粒径比例较高,小于0.05 mm粒径沉积物的比例为82.45%;吸附实验研究表明,粒径小于0.005 mm和0.005-0.01 mm沉积物中Cu含量较高,且此粒径沉积物对Cu（Ⅱ）的吸附量最大;吸附动力学研究表明,沉积物的吸附过程分为快反应和慢反应两个阶段,且吸附过程以表面吸附为主,伪二级动力学方程对动力学曲线拟合较好,其R2值达0.999以上。吸附热力学的研究结果表明：Freundlich方程比较适合描述沉积物对Cu2＋的吸附等温线,其R2大于0.99,对照区、养殖区和生活污水区沉积物对Cu（Ⅱ）的最大吸附量分别为229.20,249.98,261.20 mg.kg-1,方程式中的强度因子1/n不适合描述沉积物与重金属离子的结合能力。     

Lichtallergien und andere Lichtempfindlichkeitsreaktionen

Adverse reactions of the skin to light comprise a number of different dermatologic conditions. In light-‘allergies’ in the narrower sense non-ionised electromagnetic radiation (ultraviolet (UV)-A/-B radiation or visible light) provokes an immunologic or allergic skin reaction. These include solar urticaria, an, immunoglobulin E-mediated, immediate-type allergic photoreaction, photoallergic contact dermatitis and photoallergic (drug) exanthema, which are cell-mediated, delayed-type allergic photoreactions due to photosensitization, chronic actinic dermatitis and polymorphic light eruption. Beyond it there are nonimmunologic photosensitive and photoaggravated skin diseases, like exogenous and endogenous phototoxicity, xeroderma pigmentosum, which is based on a genetic defect, or the autoimmune disease lupus erythematosus.