微纳米气泡催化氧化强化污泥减量及脱水性能研究

以FeSO_4为催化剂,耦合空气微纳米气泡或臭氧微纳米气泡处理污泥,分析了两种气源条件下污泥干重减量效果及污泥脱水性的变化。结果表明,反应时间85 min,处理温度30℃,pH=3,Fe⁽²⁺⁾浓度2 mmol/L的最佳工艺条件下,空气微纳米气泡处理后污泥干重减少率达38.56%;臭氧微纳米气泡处理污泥干重减少率达44.88%,此时污泥脱水CST值降低率分别为66.57%和72.37%,污泥VSS/TSS值分别降至0.615和0.57,污泥稳定性提升。污泥减量效果和脱水性能提升的原因在于微纳米气泡的高级氧化能力和类芬顿反应的形成。     

微纳米气泡耦合Fe3O4催化氧化吸收烟气中的NO

以Fe3O4作为催化剂,耦合微纳米气泡在SO2存在的情况下催化氧化吸收烟气中的NO.研究了各种因素变化对Fe3 O4耦合微纳米气泡催化氧化去除NO的影响.采用XRD、SEM、EDS和XPS表征手段对反应前后的Fe3 O4进行了表征.结果表明,当Fe3 O4投加量为5 g、pH为3、NO的进气量为50 mL/min时,N...     

微纳米气泡耦合Fe_3O_4催化氧化吸收烟气中的NO

以Fe_3O_4作为催化剂,耦合微纳米气泡在SO_2存在的情况下催化氧化吸收烟气中的NO。研究了各种因素变化对Fe_3O_4耦合微纳米气泡催化氧化去除NO的影响。采用XRD、SEM、EDS和XPS表征手段对反应前后的Fe_3O_4进行了表征。结果表明,当Fe_3O_4投加量为5 g、pH为3、NO的进气量为50 mL/min时,NO的氧化吸收效率最高,达93.8%。Fe_3O_4同时含有Fe⁽²⁺⁾和Fe(2+)和Fe⁽³⁺⁾的特殊属性可促进NO的高效脱除,Fe_3O_4反应前后物相没有发生变化。     

微纳米气泡复合高级氧化技术降解污染物研究进展

介绍了难降解有机废水在水处理方面的特点,以及高级氧化技术降解有机污染物的机理,叙述了微纳米气泡的定义、特性和常见的产生方式,分析了各种常见的微纳米气泡复合高级氧化技术的应用,重点介绍了臭氧微纳米气泡技术和光催化微纳米气泡技术,总结了微纳米气泡复合高级氧化技术各种常见的实验装置及其应用.得出微纳米气泡作为一种新型的高级氧...     

微纳米气泡耦合尿素同时脱除NO和SO2及其机理的研究

利用基于尿素溶液的微纳米气泡气液分散体系实施同时脱除NO和SO₂,并考察了不同参数对脱除的影响。结果表明,各种所考察的参数对SO₂脱除效率均无显著影响,但均影响了NO的脱除效率。随着尿素溶液初始pH、尿素浓度以及SO₂浓度的提高,NO的脱除效率均先升高后降低;提高尿素溶液初始温度或NO浓度会降低NO的脱除效率。此外,通过机理分析发现,微纳米气泡释放的羟基自由基对NO和SO₂的脱除起了主导作用,尿素能进一步促进NO的脱除。     

柴油车尾气净化催化技术进展

介绍了柴油车尾气排放的特性及主要污染物;从颗粒物的催化再生技术、贫燃条件下NOx的选择性催化还原技术以及氧化催化技术等几个方面对柴油车尾气净化技术;尤其是催化技术进行了探讨;并提出了未来柴油车用催化剂的发展方向。     

微纳米气泡臭氧高级氧化工艺处理电镀废水的中试

对江苏省某电镀园区污水厂尾水使用微纳米气泡臭氧高级氧化工艺进行深度处理中试研究,要求处理后达到《地表水环境质量标准》(GB 3838—2002)Ⅴ类标准.半连续流试验结果表明,单独臭氧氧化处理无法有效去除有机物,加入双氧水催化臭氧微纳米气泡处理后可以使COD达标.在臭氧与双氧水投加量摩尔比为2时,投加64.6 mg/L...     

喷淋耦合微纳米气泡同时脱硫脱硝研究

采用喷淋耦合微纳米气泡法,即微纳米气泡分散体系与部分循环水一起进入吸收塔上部喷淋,模拟烟气从吸收塔下部进入,气液两相充分接触氧化吸收,达到脱硫脱硝的目的。结果表明:当SO_2浓度为1 142 mg/m³,NO_x浓度为1 000 mg/m3,NO_x浓度为1 000 mg/m³,水溶液pH为5,水温20℃,微纳米气泡分散体系在整个喷淋水溶液中占比50%,浸没深度为50 cm,进气量为60 L/min,喷淋水量为3.3 L/min,填料高度为120 cm, SO_2去除率达98.72%,NO_x去除率达70.45%。本实验特点是仅利用清水就可以同时脱硫脱硝。     

柴油车尾气污染物排放特征及尾气处理研究

柴油汽车性能优越,在交通领域应用广泛,但是随之而来的尾气排放问题已经成为空气污染的重要源头。柴油车尾气中的颗粒物、NO_X以及VOCs等成分给周围生态环境治理带来了极大的挑战。通过开展污染物特征分析,明确了柴油车尾气中的主要污染物成分和含量,并针对性地探讨了尾气处理措施,以期缓解环境污染问题,为同类研究提供参考。     

微气泡臭氧催化氧化深度处理化工园区废水研究

以酸/碱改性和Cu负载活性炭为催化剂,采用微气泡催化臭氧氧化深度处理化工园区废水。结果表明,经该工艺处理后,出水COD降至20 mg/L以下,发光抑制率降至-1.2%~-7.3%,B/C升至0.29~0.37,消除了废水生物毒性,并提高了废水可生化性。硝酸改性并负载Cu组分活性炭具有更强的催化活性,COD去除率和去除负荷分别可达70.8%和0.478 kg/(m~3·d),臭氧利用率为97.5%,催化臭氧氧化反应效率为0.554 mg COD/mgO_3。     

高压正极材料LiNi_(0.5)Mn_(1.5)O_4锂离子电池阻燃电解液的研究

研究了甲基磷酸二甲酯(DMMP)含量对1 mol/L Li PF6/EC∶DEC∶EMC(1∶1∶1)电解液的电化学稳定性、热稳定性及电导率的影响,并首次将含DMMP的阻燃电解液应用于高压材料LiNi_(0.5)Mn_(1.5)O_4中。结果表明,加入DMMP添加剂后电解液的热稳定性得到提高,但是该添加剂电解液的电导率有所降低。研究了DMMP对LiNi_(0.5)Mn_(1.5)O_4扣式电池的电化学性能的影响,循环伏安测试表明,几乎不影响电解液在高压条件下的使用,充放电测试结果表明,DMMP的使用会降低电池的循环性能,当DMMP含量为5%时,对电池的循环性能影响较小。此外,交流阻抗(EIS)分析表明,DMMP对循环性能影响的主要原因是内阻随着循环的增加而增大。     

基于DOC+SCR的船用柴油机尾气污染物脱除实验

在发电柴油机台架上,通过SMG 100颗粒分析仪、Testo 350烟气分析仪等设备测试了加装DOC和SCR后柴油机在额定转速时6个工况点的排放特性,分析了DOC对CO、NO_x和PM的影响,以及不同功率和喷氨量时SCR的脱硝率。结果表明,温度对DOC影响很大,当温度高于250℃,CO的脱除率在96%以上。在中低负荷时,DOC对PM的质量浓度脱除率在76%以上,但在满负荷时,由于柴油机燃烧快速恶化,PM浓度快速增大,此时的PM脱除率仅为36%。DOC能将NO转化为NO₂,但对NO_x的总浓度几乎不产生影响。SCR受温度和氨氮比的影响比较大,当温度高于250℃,氨氮比为1时,脱硝率几乎达到100%。通过与多篇文献的对比分析,采用功率与催化剂体积之比作为钒基SCR的初期选型参数可能更加合适。     

Thermally stable metal ruthenate based soot oxidation catalyst for diesel exhaust emission control

Lanthanum ruthenate materials with perovskite type structure can be easily synthesized with ruthenium in 4+ oxidation state. La_3.5Ru_4.0O₁₃ type perovskite has been synthesized in unsupported and supported forms by using various methods. This perovskite type La_3.5Ru_4.0O₁₃ phase shows high thermal stability and can therefore be used as a catalyst for high temperature applications, including those for auto-exhaust emission control. The material shows good catalytic activity for the carbon/soot oxidation in view of its possible application in diesel soot oxidation for regeneration of Diesel Particulate Filter.     

复合氧化物的制备及其在碳黑颗粒物氧化中的应用

采用柠檬酸络合燃烧法合成钾铈和钾铈镧复合氧化物催化剂。利用XRD对复合氧化物进行了表征。利用程序升温反应（TPR）方法研究了其对碳黑颗粒物的催化氧化性能,考查了焙烧温度、焙烧时间、前驱体中K、Ce的物质的量比等制备条件对催化剂活性的影响及稳定性。结果表明：钾铈镧复合氧化物对碳黑颗粒物具有较高的催化活性和稳定性。     

Ceramic foam as a potential molten salt oxidation catalyst support in the removal of soot from diesel exhaust gas

An exploratory study has been carried out to determine the potential of open-pore ceramic foam as support for molten-salt diesel soot oxidation catalysts. These catalysts are based on eutectic mixtures of Cs₂O, V₂O₅, MoO₃, and Cs₂SO₄. Open-pore ceramic foams are very interesting, since they can act as supports and as soot filters. 50 ppi -alumina foam has been tested as support substance. Attractive methods have been developed for depositing the molten salt on the external surface of the pore walls of the foam. The combustion of ‘loose-contact’ synthetic soot has been analysed with a micro-flow reactor. The oxidation rate is a function of the amount of molten salt deposited on the foam. Stable rates in the range from 5 to 25 μg_soot/g_soot,initial/s at 650 K have been observed. These rates are in the same order of magnitude as measured for the best catalytic fuel additives; and, therefore, catalytic foams are very promising. The initially minor ‘deactivation’ that occurs after the thermal treatment up to 100 h at 725 K probably has a physical explanation. During the treatment, the molten salt redistributes to a configuration that has less catalyst available for accelerating the soot oxidation.     

Size-distribution dependent lung deposition of diesel exhaust particles

Lung deposition fractions of nine experimental particle number distributions emitted by various light duty diesel vehicles with different after-treatment devices and fuels were calculated with a stochastic lung deposition model. The emitted volatile and non-volatile mass fractions were treated separately as the corresponding biological response in the human respiratory tract differs. The health related effects of the volatile mass fraction, referred to as the chemical effect, were associated with the deposited volatile mass. The deposited volatile mass depends on the total emitted volatile mass concentration, on its distribution (mass median diameter of nucleation mode and surface area median of the accumulation mode), and on the ratio of the volatile mass in the nucleation and accumulation modes. The effect of the non-volatile mass fraction, referred to as the physical effect, was associated with the surface area distribution of the accumulation mode. The deposited surface area of the non-volatile fraction depends on its emitted concentration and on the surface area median diameter of the size distribution. The calculations suggest the importance of selecting the appropriate distribution (surface, volatile or non-volatile mass) for an assessment of the health effects of diesel exhaust particles, and the importance of combined particulate mass and number distribution measurements.     

Oxidation of propane over a diesel exhaust catalyst

The oxidation of propane, over a concentration range of 0.30 to 1.04 mole % in air was investigated over a commercial diesel exhaust catalyst consisting of CuO, Cr₂O₃ and Pd supported on Al₂O₃. The rate of reaction was correlated by a first order, irreversible rate function; the resulting pre-exponential factor and activation energy were 3.15 × 10⁷ cc/g-sec and 21.3 kcal/gmole, respectively. At high temperatures the reaction rate became influenced by pore diffusion. A temperature of 675°K was required to obtain 50% propane conversion. It was concluded that this catayst is unsuitable for catalytic mufflers on diesel buses since the measured value of diesel exhaust temperatures at the cataytic muffler inlet is significantly less than 675°K.     

Instability and breakup of cavitation bubbles within diesel drops

A modified mathematical model is used to study the effects of various forces on the stability of cavitation bubbles within a diesel droplet. The principal finding of the work is that viscous forces of ...