Ag/Al2O3催化剂还原NO性能的研究

采用溶胶-凝胶法制备Ag/Al2O3催化剂系列,研究了活性组分Ag的负载量、焙烧温度、氧气浓度、还原剂C3H6以及NO浓度对Ag/Al2O3催化剂催化活性的影响.     

CuO/Al2O3烟气脱硫技术及脱硫剂的研究进展

对CuO/Al2O3烟气脱硫技术的特点及其原理作了初步介绍，并翔实地阐述了国内外CuO/Al2O3脱硫剂的研究进展，提出了几点研究心得。     

Fe/SiO_2复合材料的制备及其对Cd~(2+)的吸附

以Na_2SiO_3为原料、聚乙二醇-2000为结构导向剂,采用溶胶-凝胶和高温煅烧两步法制备SiO_2微球,再以其为载体,采用液相还原法负载零价纳米铁,制得Fe/SiO_2复合材料。采用SEM,FTIR,XRD技术对Fe/SiO_2复合材料的形貌结构进行表征,研究了Fe/SiO_2复合材料对Cd~(2+)的吸附性能。表征结果显示,纳米铁以毛绒状负载在SiO_2微球上。实验结果表明,在溶液pH为5、n(SiO_2):n(Fe)=2、老化温度为70℃的最佳工艺条件下制备的Fe/SiO_2复合材料在25℃时处理Cd~(2+)初始质量浓度为35 mg/L的模拟含Cd~(2+)废水,Cd~(2+)吸附容量为28.10 mg/g。Fe/SiO_2复合材料对Cd~(2+)的吸附作用较符合准二级吸附动力学方程,对Cd~(2+)的等温吸附过程更符合Langmuir模型。     

Fe(Ⅱ)、Fe(Ⅲ)和Fe(Ⅵ)活化过硫酸盐氧化降解水中的菲

分别采用Fe(Ⅱ)、Fe(Ⅲ)和Fe(Ⅵ)活化过硫酸盐(PS)氧化降解水中的菲,考察了反应pH、药剂投加量及氧化时间等因素的影响,并对比了不同价态铁活化PS对菲的氧化降解效果.在反应pH为8、n(菲):n(Fe):n(PS)为1:2:2的优化条件下,反应60 min后Fe(Ⅱ)-PS和Fe(Ⅲ)-PS体系对菲的去除率分...     

环境友好固体超强酸SO2-4/Fe2O3 催化合成阿斯匹林的研究

制备固体超强酸SO2-4/Fe2O3,并测定其红外光谱,首次将其作为催化剂应用于合成阿斯匹林.考察了反应时间、反应温度、催化剂用量、酸醇摩尔比等对水杨酸酰化反应的影响.研究结果表明,最佳条件下收率可达88.8%.SO2-4/Fe2O3对合成阿斯匹林的反应具有良好的催化作用,是能代替浓硫酸作为水杨酸乙酰化的对环境友好的优良催化剂.     

羟基磷灰石去除废水中的Fe3+

以天然磷矿粉制备的羟基磷灰石(HAP)作为吸附剂,处理模拟含Fe3+废水。实验结果表明,在HAP加入量为1.0g/L、初始模拟废水pH为3.00、反应温度为室温的最佳条件下,处理初始Fe3+质量浓度为150mg/L的模拟废水,反应90min后Fe3+去除率为99.89%,处理后模拟废水中Fe3+质量浓度为0.15mg/L,低于0.30mg/L,达到GB5749—2006《生活饮用水卫生标准》的要求。     

Fe3+强化NaClO2溶液脱硝过程研究

以NaClO_2-Fe~(3+)为复合吸收剂,在填料吸收塔中进行了脱硝实验。实验结果表明:Fe~(3+)能够显著提高NaClO_2的氧化活性,1.0 mmol/L NaClO_2溶液加入0.10 mmol/L Fe~(3+)后即可达到5.0 mmol/L NaClO_2溶液不加Fe~(3+)时的脱硝水平;在NaClO_2浓度1.0 mmol/L、Fe~(3+)浓度0.10 mmol/L、吸收液初始pH 3.75、反应温度60 ℃、液气比8 L/m~3的优化工艺条件下处理NO 140 mg/m~3的进气,NO氧化率和NO_x脱除率分别达到92.63%和83.62%。脱硝前后吸收液组成的测定结果表明:起主要脱硝作用的是ClO_2;反应消耗的NaClO_2与NO的摩尔比为1.06。通过补加消耗的NaClO_2可达同样的脱硝效果,循环3次后吸收液中的有效成分基本稳定。     

Is The Ca + K + Mg/Al Ratio in the Soil Solution a Predictive Tool for Estimating Forest Damage?

The ratio between (Ca +K +Mg) and Al in nutrientsolution has been suggested as a predictive tool forestimating tree growth disturbance. However, the ratiois unspecific in the sense that it is based on severalelements which are all essential for plant growth;each of these may be growth-limiting. Furthermore,aluminium retards growth at higher concentrations. Itis therefore difficult to give causal and objectivebiological explanations for possible growthdisturbances. The importance of the proportion ofbase-cations to N, at a fixed base-cation/Al ratio, isevaluated with regard to growth of Picea abies.The uptake of elements was found to be selective;nutrients were taken up while most Al remained insolution. Biomass partitioning to the roots increasedafter aluminium addition with low proportions of basecations to nitrogen. We conclude that the low growthrates depend on nutrient limitation in thesetreatments. Low growth rates in the high proportionexperiments may be explained by high internal Alconcentrations. The results strongly suggest thatgrowth rate is not correlated with the ratio in therooting medium and question the validity of usingratios as predictive tools for estimating forestdamage. We suggest that growth limitation of Picea abies in the field may depend on lowproportions of base cations to nitrate. It istherefore important to know the nutritional status ofthe plant material in relation to the growth potentialand environmental limitation to be able to predict andestimate forest damage.     

生物氧化提金废水中的Fe、As共沉淀

采用Fe、As共沉淀工艺处理强酸性高砷生物氧化提金废水。通过向强酸性高砷生物氧化提金废水中加入浓氨水控制反应液pH,生成FeAsO_4和Fe(OH)_3沉淀,达到Fe、As共沉淀的目的,为后续工艺进一步回收利用Fe、As奠定基础。实验结果表明,在反应液pH为4.5、搅拌转速为500 r/min、反应温度为25℃的条件下,Fe回收率达到99.9%,As回收率为99.8%。处理后废水中As质量浓度小于20μg/L,符合GB3838—2002《地表水环境质量标准》中的Ⅰ,Ⅱ,Ⅲ类水体中As含量标准。     

Dynamic studies on lead volatilization from CaO–SiO2–Al2O3 molten slag under N2–CO–CO2, N2–HCl and N2–H2S gas atmospheres

Dynamic studies on the volatilization of lead from CaO–SiO₂–Al₂O₃ molten slags were conducted in a lab-scale melting furnace from 1623 to 1773 K under different mixed gas atmospheres of CO 0.05–0.3 atm to CO₂ 0–0.3 atm to N₂ (balance), HCl 1.7 × 10^?3–6.7 × 10^?3 atm to N₂ (balance), and H₂S 3.0 × 10^?4 to 1.7 × 10^?3 atm to N₂ (balance). The slag samples consisted of the mixed powders of 20–50 wt% CaO, 30–60 wt% SiO₂, and 10–40 wt% Al₂O₃, containing 2000 ppm PbO.Results showed that the rates of volatilization of lead from the CaO–SiO₂–Al₂O₃ molten slags under the N₂–CO–CO₂, N₂–HCl, and N₂–H₂S gas atmospheres were higher than those under the simulated air (N₂–O₂), which increased with CO, HCl, and H₂S partial pressures. At \(p_{{HCl}}\)  =  \(p_{H_{2}S}\)  = 1.7 × 10^?3 atm, the apparent rate constants for the volatilization of lead under the N₂–H₂S and N₂–HCl gas atmospheres were nearly equal, which increased with a rise in temperature. Results also showed that the rate of volatilization of lead from the molten slag decreased drastically with the increasing viscosity of the molten slag, in the viscosity range lower than 3 Pa s. Consequently, the volatilization of lead from the CaO–SiO₂–Al₂O₃ molten slag was significantly influenced by CO, HCl, and H₂S partial pressures and by the viscosity of the molten slag.     

Fe2+/活性炭非均相Fenton试剂氧化法降解苯酚

采用Fe2+/活性炭非均相Fenton试剂催化处理高浓度模拟苯酚废水.以体积分数为40％的硫酸对颗粒活性炭进行预处理后加入质量分数为10％的硫酸亚铁溶液,制备Fe2+/活性炭.在非均相Fenton试剂氧化体系中,Fe2+/活性炭初次使用时,苯酚去除率为92％;连续重复使用5次,苯酚去除率仍可达53％.     

微波诱导催化剂Fe2O3-CeO2/γ-Al2O3的制备及其对甲基橙的催化降解性能

采用分层浸渍法制备了微波诱导催化剂Fe2O3-CeO2／γ—Al2O3。采用X射线衍射（XRD）和扫描电镜（SEM）等方法对所制备的催化剂进行了表征。以甲基橙为目标降解物,考察了该催化剂在微波诱导氧化工艺（MIOP）中的催化活性。实验结果表明,在微波输出功率为450W、催化剂加入量为10g/L的条件下,处理50mL质量浓度为25mg／L的甲基橙溶液,微波照射处理3min后,甲基橙溶液的脱色率达93．6％。     

用Fe3+掺杂锐钛矿型TiO2光催化剂降解孔雀石绿

以硫酸钛为原料,用水热法制备了Fe3+掺杂锐钛矿型TiO2(Fe3+ - TiO2)粉末,用扫描电子显微镜测定了试样的形貌.研究了自制的Fe3+ - TiO,光催化剂对孔雀石绿的光催化降解作用.实验结果表明,在孔雀石绿溶液质量浓度为2 mg/L、Fe3+ - TiO2加入量为1.616 g/L、Fe3+-TiO2中Fe...     

Methane mass balance at three landfill sites: What is the efficiency of capture by gas collection systems?

Many developed countries have targeted landfill methane recovery among greenhouse gas mitigation strategies, since methane is the second most important greenhouse gas after carbon dioxide. Major questions remain with respect to actual methane production rates in field settings and the relative mass of methane that is recovered, emitted, oxidized by methanotrophic bacteria, laterally migrated, or temporarily stored within the landfill volume. This paper presents the results of extensive field campaigns at three landfill sites to elucidate the total methane balance and provide field measurements to quantify these pathways. We assessed the overall methane mass balance in field cells with a variety of designs, cover materials, and gas management strategies. Sites included different cell configurations, including temporary clay cover, final clay cover, geosynthetic clay liners, and geomembrane composite covers, and cells with and without gas collection systems. Methane emission rates ranged from -2.2 to >10,000 mg CH(4) m(-2) d(-1). Total methane oxidation rates ranged from 4% to 50% of the methane flux through the cover at sites with positive emissions. Oxidation of atmospheric methane was occurring in vegetated soils above a geomembrane. The results of these studies were used as the basis for guidelines by the French environment agency (ADEME) for default values for percent recovery: 35% for an operating cell with an active landfill gas (LFG) recovery system, 65% for a temporary covered cell with an active LFG recovery system, 85% for a cell with clay final cover and active LFG recovery, and 90% for a cell with a geomembrane final cover and active LFG recovery.     

Preparation of ε-Caprolactone/Fe3O4 Magnetic Nanocomposite and Its Application to the Remazol Brilliant Violet 5R Dye Adsorption from Wastewaters by Using RSM

Journal of Polymers and the Environment - In this study, poly (ε-caprolactone)/Fe3O4 magnetic nanocomposite (PCL/Fe3O4 MNC) was synthesized by ring-opening polymerization. Then, PCL/Fe3O4 MNC...