PW_(12)/g-C_3N_4光催化降解甲基橙

采用浸渍法制备了磷钨酸(PW12)/g-C3N4复合光催化剂,并将其用于溶液中甲基橙的光催化降解,运用IR技术对使用前后的光催化剂进行了表征。表征结果显示,PW12和g-C3N4的结构未在浸渍负载中发生改变,且PW12和g-C3N4结合牢固。实验结果表明:最佳的PW12负载量(光催化剂中PW12的质量分数)为50%;光催化降解甲基橙的优化反应条件为初始甲基橙质量浓度5 mg/L、光催化剂加入量0.6 g/L、初始溶液p H=7;在优化条件下,分别采用紫外光、模拟太阳光、可见光照射120 min后,甲基橙的降解率分别为96.59%,82.23%,42.78%;该光催化剂固载良好,使用中不易发生溶脱,稳定性好,可重复使用。     

MCM-41分子筛负载铁铈催化降解甲基橙

采用等体积浸渍法制备了负载型有序介孔Fe-Ce/MCM-41催化剂。研究了该催化剂降解甲基橙的适宜工艺条件,并采用XPS,XRD,TEM技术对该催化剂进行了表征。实验结果表明,该催化剂Fenton氧化降解甲基橙的较适宜工艺条件为:溶液pH 5.0、甲基橙溶液初始质量浓度100 mg/L、催化剂加入量2.0 g/L、H_2O_2浓度20 mmol/L,在此适宜条件下反应120 min时,甲基橙去除率接近100%。表征结果显示:Fe-Ce/MCM-41催化剂主要由铁、铈、氧、碳4种元素组成;铁与铈的摩尔比接近3∶1;铁和铈主要以Fe_3O_4和CeO_2的形态存在于催化剂表面。     

微等离子弧放电催化水处理技术的研究

采用钛为阳极的微等离子弧放电技术,研究了在模拟废水处理中放电催化效应及其机理,发现该技术对甲基橙有好的放电催化处理效果.甲基橙的脱色程度与峰值电压、脉冲频率、占空比、阳极电极面积等有关.在0.3mol·L-1的H3PO4电解液中,在峰值电压为550V、脉冲频率200Hz,占空比1∶180、阳极电极面积50mm×50mm条件下,20min内600mL、20mg·L-1的甲基橙溶液脱色率达90%.实验结果表明,该放电催化体系具有协同效果好、能效高、反应器设计要求简单等特点,是一种有发展前景的水处理新技术.     

西安市表层土壤中邻苯二甲酸酯(PAEs)含量与构成

通过在西安市三环内6个功能区布设62个采样点,采样分析其表层土壤中邻苯二甲酸酯(PAEs)质量比及其构成特征。结果表明,西安市表层土壤中DMP、DEP、BBP、DnBP、DEHP和DnOP平均值分别为0.188 mg/kg、0.187 mg/kg、0.091 mg/kg、4.174 mg/kg、6.122 mg/kg和0.188 mg/kg,6种PAEs总质量比(∑6PAEs)范围为1.54 mg/kg^153.17 mg/kg,平均值为10.95 mg/kg。6个功能区∑6PAEs从高到低为交通区>工业区>混合区>公园>文教区>住宅区。与其他城市表层土壤中PAEs值比较发现,DMP处于高水平,DEP、DnBP、DEHP和∑6 PAEs处于较高水平,BBP和DnOP处于中等水平。     

Characteristics of stable biodiesel emulsion fuel with the aid of lipophilic surfactant,polyglycerol polyricinoleate (PGPR)

ABSTRACT

Biodiesel emulsion fuel is reported as one of the most feasible options capable of generating lower NOx emission than that from fossil fuels. However, oil and water in the emulsion fuel are easily separated and unstable. The aim of the present study is to consider the production and stability of biodiesel emulsion fuel by using tetraglycerin ester (CR-310), i.e., one of lipophilic surfactant, polyglycerol polyricinoleate (PGPR) and biodiesel, i.e., Waste cooking Oil Methyl Ester (WOME) produced based on waste cooking oil. The corresponding heat rate, water content, and viscosity are measured. Emphasis is placed on the effects of water content and surfactant on biodiesel emulsions. It is found that: (i) stable emulsion fuel is obtained by adding at least 2.0% of CR-310 and is maintained over 1 month, (ii) there is no effect of water content on stable emulsion fuel if CR-310 is used over 2.0%, and (iii) the viscosity of emulsion fuels is higher than that of the biodiesel fuel and is gradually increased with an increase in the water content.     

催化燃烧处理有机废气及催化剂中毒的防止

研究了在Ｐｔ、Ｐｄ、Ｃｅ多组分蜂窝状催化剂上乙醇、环己烷和苯的氧化性能及水蒸气对催化剂活性的影响,探讨了如何防止硫化氢和甲硫醇引起的催化剂中毒。     

Fuel efficiency improvement of a dual-fuel engine fuelled with Honge oil methyl ester (HOME)–bioethanol and producer gas

Renewable and alternative fuels have numerous advantages compared with fossil fuels as they are renewable and biodegradable and provide food and energy security and foreign exchange savings besides addressing environmental concerns and socio-economic issues (Yaliwal et al. 2013. International Journal of Sustainable Engineering, doi:10.1080/19397038.2013.801530. Zhu et al. 2011a, Applied Thermal Engineering 31 (14–15): 2271–2278; Zhu et al. 2011b, Fuel 90: 1743-1750; Banapurmath, Tewari, and Hosmath 2008, Renewable Energy 33: 2007-2018; Banapurmath 2009, “Performance, Combustion and Emission Characteristics of a Single Cylinder Direct Injection CI Engine Operated on Dual Fuel Mode Using Honge Oil and Producer Gas.” PhD thesis, 1–195; Banapurmath et al. 2011, Waste and Biomass Valorization 2: 1–11). In this context, the main objective of the present work is to study methods of biofuel production such as Honge oil methyl ester (HOME) using a conventional transesterification process and bioethanol from the Calliandra calothyrsus shrub using a new pretreatment method known as hydrothermal explosion. Further, experimental investigations were carried out on a single-cylinder, four-stroke, direct-injection stationary diesel engine operating in a dual-fuel mode using HOME, bioethanol and producer gas combinations to determine its performance, combustion and emission characteristics. The performance of the dual-fuel engine was analyzed at optimized engine conditions. HOME-Bioethanol (BE) blends such as HOME+ 5% bioethanol (BE5), HOME+ 10% bioethanol (BE10) and HOME+ 15% bioethanol (BE15) were prepared by adding bioethanol to HOME (on volume basis) in different proportions ranging from 5 to 15% with an increment of 5%. In this present work, the effect of different BE blends on the performance of producer gas fuelled dual fuel engine was studied. Experimental investigation on dual fuel engine using BE5-Producer gas operation resulted in up to 4–9% increased brake thermal efficiency with decreased hydrocarbon (HC), carbon monoxide (CO) and marginally increased nitric oxide (NOx) emission levels compared to HOME-Producer gas, BE10-producer gas and BE15-producer gas mode of operation. However, it was observed that, the overall performance of BE-producer gas operation was found to be lower compared to diesel-producer gas operation.     

Performance,combustion and emission characteristics of a single-cylinder,four-stroke,direct injection diesel engine operated on a dual-fuel mode using Honge oil methyl ester and producer gas derived from biomass feedstock of different origin

Renewable and alternative fuels have numerous advantages compared with fossil fuels, as they are renewable and biodegradable, and provide food and energy security and foreign exchange savings besides addressing environmental concerns and socio-economic issues. In this context, present work was carried out to investigate the feasibility of alternative and renewable fuels derived from biomass feedstock of different origin for engine applications. The present study was also extended to study the effect of producer gas composition derived from different biomass feedstock on the performance, combustion and emission characteristics of a single-cylinder, four-stroke, direct injection stationary diesel engine operated on a dual-fuel mode using Honge oil methyl ester (HOME) and producer gas induction. The performance of the engine was evaluated with a constant injection timing of 27° before top dead centre, an injection pressure of 205 bar for the diesel–producer gas combination and 230 bar for the HOME–producer gas combination and a compression ratio of 17.5. The results showed that the performance of the dual-fuel engine varies with the composition of the producer gas and depends on the type of biomass feedstock used in the gasifier. Experimental investigations on the dual-fuel engine showed that brake thermal efficiency values for the engine operated using HOME–producer gas derived from babul, neem and honge woods were found to be 17.2, 14.3 and 11.56% respectively, compared to 23.8% for diesel–producer gas operation at 80% load. However, the results showed better engine performance with lower exhaust emission levels for the operation of HOME–producer gas derived from the ordinary or babul wood compared with the operation of that derived from the neem and Honge woods. In view of this, present study reveals that use of alternative and renewable fuels for dual fuel engine can be considered as an immediate solution for the development of rural areas and emergency use in the event of severe diesel fuel shortage.     

TiO2-Cu2O/蒙脱土复合光催化剂的制备与性能

以钠基蒙脱土（MMT）为载体,先采用溶胶-凝胶法将纳米TiO₂引入到MMT层间,再采用化学沉积法将纳米Cu₂O负载在TiO₂/MMT上,制备出TiO₂-Cu₂O/MMT纳米复合光催化剂。采用XRD、SEM、紫外-可见漫反射技术对催化剂进行了表征。以甲基橙为目标污染物,考察了催化剂的光催化性能。表征结果显示：TiO₂与Cu₂O均匀分布在MMT的表面与片层孔隙中;TiO₂-Cu₂O/MMT结合了TiO₂和Cu₂O的特性,拓宽了催化剂的光吸收范围。实验结果表明,在光源为可见光、初始甲基橙质量浓度为20 mg/L、光催化剂加入量为2 g/L的条件下,TiO₂-Cu₂O/MMT纳米复合光催化剂对甲基橙的光催化降解效果明显优于单一负载的Cu₂O/MMT和TiO₂/MMT,大幅提高了催化剂的光催化效率,反应300 min时TiO₂-Cu₂O/MMT对甲基橙溶液的脱色率达到93%。     

Nitrous oxide and methane emission from a flooded rice field as influenced by separate and combined application of herbicides bensulfuron methyl and pretilachlor

Combination of divergent active principles to achieve broad-spectrum control is gaining popularity to manage the weed menace in intensive agriculture. However, such application could have non-target impacts on the soil processes affecting soil ecology and environmental interactions. A field experiment was conducted to investigate the impact of separate and combined applications of herbicides bensulfuron methyl and pretilachlor on the emission of N₂O and CH₄, and related soil and microbial parameters in a flooded alluvial field planted to rice cv Lalat. Single application of the herbicide bensulfuron methyl or pretilachlor resulted in a significant reduction of N₂O and CH₄ emissions while the combination of these two herbicides distinctly increased N₂O and CH₄ emissions. Cumulative N₂O emissions (kg N₂O-N) followed the order of bensulfuron methyl (0.35 kg ha⁻¹) < pretilachlor (0.36 kg ha⁻¹) < control (0.45 kg ha⁻¹) < bensulfuron methyl 0.6% + pretilachlor 6.0% single dose (0.49 kg ha⁻¹) < bensulfuron methyl 0.6% + pretilachlor 6.0% double dose (0.54 kg ha⁻¹). Cumulative CH₄ emissions (kg CH₄), on the other hand, followed the order of bensulfuron methyl (47.89 kg ha⁻¹) < pretilachlor (73.17 kg ha⁻¹) < bensulfuron methyl 0.6% + pretilachlor 6.0% single dose (93.50 kg ha⁻¹) < control (106.54 kg ha⁻¹) < bensulfuron methyl 0.6% + pretilachlor 6.0% double dose (124.67 kg ha⁻¹). The inhibitory effect of separate application of herbicides bensulfuron methyl 0.6% and pretilachlor 6.0% on N₂O emission was linked to lower mineral N, lower denitrifying and nitrifying activity and low denitrifier and nitrifier populations. Inhibitory effect on CH₄ emission, on the contrary, was linked to prevention in the drop of redox potential, lower readily mineralizable carbon (RMC) and microbial biomass carbon (MBC) contents as well as lower methanogenic and higher methanotrophic bacterial population. Admittedly, stimulatory effect of combined application of herbicides bensulfuron methyl 0.6% and pretilachlor 6.0% at double dose on N₂O and CH₄ emission was related to reversal of the identified indicators of inhibition. Results indicate that while individual application of herbicides bensulfuron methyl 0.6% or pretilachlor 6.0% can reduce N₂O and CH₄ emission from flooded soil planted to rice, their combined application at normal dose can keep the emission at a comparatively lower level with significantly higher grain yield as compared to the herbicides applied alone.