纳米Fe_3O_4强化混凝-Fenton氧化预处理垃圾渗滤液

采用纳米Fe_3O_4与Fe Cl3制备复合混凝剂,利用混凝沉淀-Fenton氧化工艺预处理垃圾渗滤液原水,研究其处理效果。结果表明:在纳米Fe_3O_4投加量为2 g/L,Fe Cl3投加量为1.4 g/L时制备的复合混凝剂,在p H值为6.5,转速为300 r/min下快速搅拌1 min,转速为100 r/min下慢速搅拌30 min,沉淀时间为30 min的条件下,COD去除率为56.8%,ρ(COD)可由5 240 mg/L降低到2 264 mg/L;利用Fenton氧化处理混凝处理出水,在H_2O_2的投加量为5.5 g/L,n(H_2O_2)∶n(Fe2+)=4,p H值为6,反应时间为80 min,反应温度为25℃的最佳条件下,COD和氨氮的去除率分别为55.7%和40.1%,最终出水ρ(COD)和ρ(氨氮)分别为1 003 mg/L和670 mg/L;该组合工艺对垃圾渗滤液有较好的处理效果,COD、色度和氨氮的去除率分别为80.8%、59.5%和76.2%。     

铁法煤业集团三台子污水处理厂的工艺改造

介绍了将铁法煤业（集团）有限责任公司三台子矿区污水处理工程工艺由以卡鲁塞尔氧化沟为主体的二级生化处理工艺改造为更适宜在北方气候条件下运行的A-O法工艺；同时对系统的启动进行了介绍。     

Effects of long-term amendment of organic manure and nitrogen fertilizer on nitrous oxide emission in a sandy loam soil

To understand the effects of long-term amendment of organic manure and N fertilizer on N2O emission in the North China Plain, a laboratory incubation at different temperatures and soil moistures were carried out using soils treated with organic manure （OM）, half organic manure plus half fertilizer N （HOM）, fertilizer NPK （NPK）, fertilizer NP （NP）, fertilizer NK （NK）, fertilizer PK （NK） and control （CK） since 1989. Cumulative N2O emission in OM soil during the 17 d incubation period was slightly higher than in NPK soil under optimum nitrification conditions （25℃ and 60% water-filled pore space, WFPS）, but more than twice under the optimum denitrification conditions （35℃ and 90% WFPS）. N2O produced by denitrification was 2.1-2.3 times greater than that by nitrification in OM and HOM soils, but only 1.5 times greater in NPK and NP soils. These results implied that the long-term amendment of organic manure could significantly increase the N2O emission via denitrification in OM soil as compared to NPK soil. This is quite different from field measurement between OM soil and NPK soil. Substantial inhibition of the formation of anaerobic environment for denitrification in field might result in no marked difference in N2O emission between OM and NPK soils. This is due in part to more rapid oxygen diffusion in coarse textured soils than consumption by aerobic microbes until WFPS was 75% and to low easily decomposed organic C of organic manure. This finding suggested that addition of organic manure in the tested sandy loam might be a good management option since it seldom caused a burst of N2O emission but sequestered atmospheric C and maintained efficiently applied N in soil.     

纳米TiO2-Al2O3负载CuMnOx对甲苯的催化燃烧

研究采用改进的溶胶-凝胶法制备了TiO2-Al2O3复合载体,并用浸渍法制备CuMnOX/TiO2-Al2O3催化剂,通过对甲苯废气催化燃烧的实验,分别考察了Cu-Mn负载量、Cu/Mn摩尔比、焙烧温度及载体对催化剂制备过程及催化剂活性的影响。实验结果表明:活性组分负载量25%,铜锰活性组分的配比Cu:Mn=1:2,焙烧温度500℃是浸渍法制备CuMnOX/TiO2-Al2O3催化剂较佳的工艺条件;XRD衍射图谱表明,500℃下铜锰尖晶石的存在是催化剂催化活性优良的主要原因;由复合载体制备的CuMnOX/TiO2-Al2O3催化剂比单一载体制备的CuMnOX/Al2O3催化剂具有更高的甲苯转化率,其T99比单一载体要低20℃以上。     

Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting

Gaseous emission (N₂O, CH₄ and NH₃) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of CO₂ and 0.8% to 7.5% of TOC emitted as CH₄. Most of the nitrogen was lost in the form of NH₃, which account for 9.6% to 32.4% of initial nitrogen. N₂O was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could affect the NH₃ (p = 0.0189), CH₄ (p = 0.0113) and N₂O (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH₄ emission but increase the NH₃ and N₂O losses. C/N ratio could affect the NH₃ (p = 0.0442) and CH₄ (p = 0.0246) emissions significantly, but not the N₂O. Lower C/N ratio caused higher NH₃ and CH₄ emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio.     

利用粉煤灰制备高纯超细氧化铝粉体的研究

利用粉煤灰为原料制备高纯超细氧化铝粉体。给出了采用硅酸二钙晶相转变自粉化、高效分散剂———碳化法从粉煤灰中制备氧化铝方法的工艺路线 ,确定了从粉煤灰制备高纯超细氧化铝粉体的最佳工艺条件 ,为粉煤灰的高价值利用开辟了一条新途径     

Remarkable promotion effect of trace sulfation on OMS-2 nanorod catalysts for the catalytic combustion of ethanol

OMS-2 nanorod catalysts were synthesized by a hydrothermal redox reaction method using MnSO₄ (OMS-2-SO₄) and Mn(CH₃COO)₂ (OMS-2-AC) as precursors. SO₄^2 −-doped OMS-2-AC catalysts with different SO₄^2 − concentrations were prepared next by adding (NH₄)₂SO₄ solution into OMS-2-AC samples to investigate the effect of the anion SO₄^2 − on the OMS-2-AC catalyst. All catalysts were then tested for the catalytic oxidation of ethanol. The OMS-2-SO₄ catalyst synthesized demonstrated much better activity than OMS-2-AC. The SO₄^2 − doping greatly influenced the activity of the OMS-2-AC catalyst, with a dramatic promotion of activity for suitable concentration of SO₄^2 − (SO₄/catalyst = 0.5% W/W). The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), NH₃-TPD and H₂-TPR techniques. The results showed that the presence of a suitable amount of SO₄^2 − species in the OMS-2-AC catalyst could decrease the Mn–O bond strength and also enhance the lattice oxygen and acid site concentrations, which then effectively promoted the catalytic activity of OMS-2-AC toward ethanol oxidation. Thus it was confirmed that the better catalytic performance of OMS-2-SO₄ compared to OMS-2-AC is due to the presence of some residual SO₄^2 − species in OMS-2-SO₄ samples.     

多孔氧化铝层制备的研究

采用预腐蚀与交流腐蚀相结合的方法．研究了多孔氧化铝层的制备工艺．探讨了制备工艺中各步骤的作用以及影响因素。利用扫描电镜，研究了多孔氧化铝层制备工艺对铝箔微观形貌的影响。研究表明．交流腐蚀工艺对铝箔表面微观形貌的改变作用最明显。一次后处理后铝箔表面蚀孔变密．氧化膜的结构更加疏松细腻。二次后处理，调整和热处理等步骤对铝箔表面的微观形貌影响不大。     

Preliminary studies on nitrous oxide emissions from the ornithogenic soils on Xi-sha atoll, South China Sea

IntroductionNitrousoxide (N2 O)isoneofthemostimportantgreenhousegases ,anditplaysanimportantroleinthedepletionofstratosphericozone (Crutzen ,1977;Zhu ,2 0 0 4 ) .TheatmosphericN2 Oconcentrationshavebeenincreasingattherateof 0 2 %— 0 3%peryearandthegl…     

氧化石墨烯的水环境行为及其生物毒性

氧化石墨烯是一类石墨烯衍生物,性质独特,应用广泛,生产量急剧增加,其环境风险日益引起关注.氧化石墨烯具有高亲水性和表面活性,在水中易分散,易随水流发生迁移转化,可能对水环境和水生生物造成不利影响.因此,明确氧化石墨烯的水环境行为及其生态效应,对于正确理解和评估其环境风险,合理规划其使用和回收具有重要意义.目前,该领域的研究涵盖了氧化石墨烯在水环境中的分散/团聚、吸附、还原、降解、沉积等行为,及对微生物、浮游动物、藻类和鱼类等水生生物的毒性表现.本文综述了相关研究成果,分析了当前研究面临的挑战并展望其研究前景.