Kinetic and morphology study of alginate-vineyard pruning waste biocomposite vs. non modified vineyard pruning waste for dye removal

In this work a comparative bioadsorption study between a biocomposite consisting of hydrolysed vineyard pruning waste entrapped in calcium alginate spheres and non entrapped vineyard residue was carried out.Results have demonstrated that the biocomposite based on lignocellulose-calcium alginate spheres removed 77.3% of dyes,while non entrapped lignocellulose eliminated only removed 27.8% of colour compounds.The experimental data were fitted to several kinetic models(pseudo-first order,pseudo-second order,Chien–Clayton model,intraparticle diffusion model and Bangham model); being pseudo-second order the kinetic model that better described the adsorption of dyes onto both bioadsorbents.In addition,a morphological study(roughness and shape) of alginate-vineyard biocomposite was established under extreme conditions,observing significant differences between hydrated and dehydrated alginate-vineyard biocomposite.The techniques used to carry out this morphological study consisted of scanning electron microscopy(SEM),perfilometry and 3D surface analysis.     

老化对钴铈基催化剂催化氧化丙烷的影响

采用柠檬酸络合法合成Co-CeO_x多活性中心催化剂,在不同温度进行加速老化处理,测试新鲜和老化后催化剂对丙烷的催化氧化性能,同时对其结构和性质进行表征.结果表明,当加速老化温度低于650℃时,丙烷转化率达50%的温度变化幅度小于10℃;加速老化温度高于750℃时,催化剂氧化丙烷的性能快速下降.表征结果显示,Co-CeO_x催化剂主要表现为尖晶石结构,老化后晶粒尺寸显著增大,Co³⁺的含量减少,氢还原峰温度升高.加速老化处理对Co-CeO_x催化剂物理结构的影响进而抑制了其化学特性及催化活性.测试Co-CeO_x催化剂对丙酮和甲苯的催化氧化性能,分别在179和244℃达到90%的脱除效率.因此,Co-CeO_x多活性中心催化剂具有良好的氧化性能,且表现出一定的稳定性.     

湿式空气非均相催化氧化处理有机废水中难降解有机物的研究

湿式空气催化氧化是曩为经济的环境友好型高级氧化技术之一,在处理有机废水中难降解有机物方面极具前景.为提高氧化效率,钌（Ru）、铑（Rh）、铂（Pt）、钯（Pd）等贵金属及铜（Cu）、铈（Ce）、锰（Mn）、铁（Fe）、镍（Ni）、铝（Al）、铬（Cr）及钴（Co）等金属氧化物等常作为非均相催化剂应用到湿式空气催化氧化体系中.本文对非均相催化湿式空气氧化处理有机废水中难降解有机物的非均相催化剂、工艺条件及反应机理进行了探讨,最后指出了催化剂的失效、解决方法及技术发展方向.     

Study on catalysts for combustion of lean CH4

In this study, cerarnics honeycomb-supported ABO₃ perovskite type oxides were preparedby changing the composition of A and B site cations, and observed their activities for lean CH₄ oxidation. In the case of change in A site composition La_0.3Sr_0.2MnO₃ and La_0.6Sr_0.4MnO₃ is the mostactive catalysts for 1 v% CH₄ and 2 v% CH₄ respectively. But LaMn_0.5Co_0.5O₃ oxide is the best ac-tive catalyst for 1-2v% CH₄ among the oxides by changing B site compositions of LaBO₃ and su-perior to La_0.3Sr_0.2MnO₃ and La_0.6S_0.4MnO₃catalysts.Adding trace Pd improved the activity and characteristics of space velocity for LaMn_0.5CO_0.5O₃and La_0.3Sr_0.2MnO₃ Although LaMn_0.5Co_0.5O₃ +Pd (0.03 wt%) was less active than the Pd catalyst,the activity was more than Pt catalyst at a conversion level below 90%.     

CuO对贵金属/CeO_2/Al_2O_3催化剂的作用

制备含少量贵金属Ｐｔ、Ｐｄ 的不同Ｃｕ 和Ｃｅ摩尔含量比（０∶１０，１∶９，２∶８）的催化剂，实验条件下加入ＣｕＯ可以提高Ｐｔ催化剂的二效活性；加入Ｃｕ∶Ｃｅ＝ ２∶８ 的ＣｕＯ降低了Ｐｄ 催化剂的三效性能，然而Ｃｕ∶Ｃｅ＝ １∶９时可以改善Ｐｄ 催化剂的三效催化性能⒚通过结构分析，认为ＣｕＯ的存在可以提高Ｐｄ 催化剂的比表面积，改善ＰｄＯ的分散度     

固定化微生物技术及其在重金属废水处理中的应用

固定化微生物技术是一种有效的废水生物处理技术.较为全面地介绍了其定义、分类及载体选择.全面系统地介绍了固定化微生物(主要是菌类和藻类)技术近年来在重金属废水处理中的应用现状,分析认为,固定化微生物技术对于处理含各种重金属离子的废水均有很广阔的应用前景,并对今后的研究方向做了探讨.     

Formation of aromatic chlorinated compounds catalyzed by copper and iron

This study shows the catalyzing effects of iron and copper on the formation of chlorinated compounds such as chlorobenzenes (ClBzs), chlorophenols (CIPhs), polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). Both total concentrations and congener distributions have been studied. The parameters and conditions varied during the combustion tests were the complete and incomplete combustion and the metal and chlorine addition. The incomplete combustion promoted the formation of organic chlorinated compounds in flue gas particles. Highly chlorinated congeners of PCDD/F were dominant in the flue gas particles, whereas the importance of lower chlorinated congener were increased in the gas phase. In the complete combustion conditions the concentrations of PCDD/Fs increased when the degree of chlorination were high, nevertheless the concentrations of tetra and penta PCDD/Fs were higher in the gas phase than the concentrations in the fly ash particles. Organic chlorine promoted the formation of chlorinated compounds more effectively than inorganic chlorine, which instead promoted the formation of PCDD/Fs in the gas phase, especially with copper catalyst. Different concentration levels of chlorinated compounds were observed in the gas phase and in particles when the chlorine source and combustion conditions were varied from incomplete to optimum conditions. Both copper and iron seem to have a catalytic effect on PCDD/F formation.     

催化湿式氧化法处理对硝基酚钠废水的试验

以Mn-Ce-Zr-Cu复合型氧化物作为多相催化剂，采用催化湿式氧化法处理高浓度对硝基酚钠废水，考察了各种反应条件对废水处理效果的影响。结果表明：在温度220℃、压力2．5MPa、反应时间60min、催化剂加入量3g／L的条件下，COD去除率可达63．7％。经处理后的废水，BOD5／COD的比值由原来的0．016提高到0．33，从而为后续的生物降解创造了良好条件。     

载体特性对Pd-Cu/TiO2催化剂催化脱氮性能的影响

以Pd-Cu／TiO2为催化剂，采用催化加氢技术进行脱氮研究．结果表明：TiO2载体的特性对催化活性及N2选择性有显著影响，与773K和973K温度下焙烧得到的载体相比，以573K温度下焙烧得到的TiO2为载体制备的Pd（5wt％）-Cu（1．25wt％）／TiO2催化剂可显著提高催化效率及N2选择性．     

稀土-过渡金属复合氧化物催化剂用于汽车尾气净化研究

以不含贵金属的稀土 过渡族金属四元复合氧化物为催化剂 ,模拟汽车尾气的组成含量 ,运用连续流动式反应器 ,研究了四元复合氧化物La0 5Sr0 5Ni1 -xCuxO3系列 (x =0—1 0 )对CO和NOx 的催化氧化还原消除活性及其在消除反应条件的抗硫中毒能力 .实验结果表明 ,钙钛矿型四元复合氧化物催化剂La0 5Sr0 5Ni0 5Cu0 5O3对CO和NOx 的氧化还原消除都具有较高的活性 ;脉冲中毒实验指出 ,当反应温度≥ 3 0 0℃ ,SO2 在催化剂中的脉冲积累含量为 1 2 2× 1 0 - 2 mmol时 ,该复合氧化物仍表现出良好的抗硫毒性能 ,它对CO的氧化消除活性并未因体系中SO2 的存在而受到影响