Characterization of carbonic anhydrase II from Chlorella vulgaris in bio-CO2 capture

Carbonic anhydrase II (CA II) can catalyze the reversible hydration reaction of CO₂ at a maximum of 1.4?×?10⁶ molecules of CO₂ per second. The crude intracellular enzyme extract containing CA II was derived from Chlorella vulgaris. A successful CO₂ capture experiment with the presence of calcium had been conducted on the premise that the temperature was conditioned at a scope of 30?C40?°C, that the biocatalyst-nurtured algal growth period lasted 3?days, and that pH ranged from7.5 to 8.5. Ions of K⁺, Na⁺, Ca²⁺, Co²⁺, Cu²⁺, Fe³⁺, Mg²⁺, Mn²⁺, and Zn²⁺ at 0.01, 0.1, and 0.5?M were found to exhibit no more than 30?% inhibition on the residual activity of the biocatalyst. It is reasonable to expect that calcification catalyzed by microalgae presents an alternative to geological carbon capture and sequestration through a chain of fundamental researches carried on under the guidance of sequestration technology.     

Carbonyl emissions from vehicular exhausts sources in Hong Kong

Vehicular emission (VE) is one of the important anthropogenic sources for airborne carbonyls in urban area. Six types of VE-dominated samples were collected at representative locations in Hong Kong where polluted by a particular fueled type of vehicles, including (i) a gas refilling taxis station (liquefied petroleum gas [LPG] emission); (ii) a light-duty passenger car park (gasoline emission); (iii) a minibus station (diesel emission); (iv) a single-deck-bus depot (diesel emission); (v) a double-deck-bus depot (diesel emission); and (vi) a whole-food market entrance for light- and heavy-duty vehicles (diesel emission). A total of 15 carbonyls in the samples were quantified. Formaldehyde was the most abundant carbonyl among the VE-dominated samples, and its contribution to the total quantified amount on a molar basis ranged from 54.8% to 60.8%. Acetaldehyde and acetone were the next two abundant carbonyls. The carbonyls were quantified at three roadside locations in Hong Kong. The highest concentrations of formaldehyde and acetaldehyde, 22.7 +/- 8.4 and 6.0 +/- 2.8 microg/m3, respectively, were determined in the samples collected at a main transportation gate for goods between Hong Kong and Mainland China. The total quantified carbonyl concentration, 37.9 +/- 9.3 microg/m3, was the highest at an entrance of a cross-harbor tunnel in downtown area. The theoretical carbonyls compositions of the three roadside locations were estimated according to the VE-dominated sample profiles and the statistics on vehicle numbers and types during the sampling period. The measured compositions of formaldehyde were much higher than the theoretical compositions in summer, demonstrating that photochemical reactions significantly contributed to the formaldehyde production in the roadsides.     

The effects of manganese precursors on Mn-based/TiO2 catalysts for catalytic reduction of NO with NH3

Manganese acetate (MnAc) and manganese nitrate (MnN) were employed as precursors for the preparation of MnAc)/TiO2, Mn (N)/TiO2, Mn(Ac)-Ce/TiO2, and Mn(N)-Ce/TiO2 by impregnation. These complexes were used as catalysts in the low-temperature selective catalytic reduction of NO with NH3. The influence of manganese precursors on catalyst characteristics, the reduction activity, and the stability of the catalysts to poisoning by H2O and SO2 were studied. Experiments showed that Mn(N) produced MnO2 with large grain sizes in Mn(N)/TiO2 catalyst. On the contrary, Mn(Ac) led to highly dispersed and amorphous Mn2O3 in Mn (Ac)/TiO2 catalyst, which had better catalytic activity and stability to SO2 at low temperatures. The doping of cerium reduced the differences in catalytic performance between the catalysts derived from different Mn precursors.     

植物对潜流人工湿地净化微污染水效果的影响研究

以4种湿地植物为实验对象,在野外构建中试潜流人工湿地,研究了不同植物及植物连根收割对湿地运行效果的影响。结果显示,植物明显提升了湿地的去污效果;其中美人蕉湿地的TP和NH4+-N去除率最高,达到55.6%和78%;空心菜湿地的TN去除率最高,达到80.5%;芦竹湿地的COD去除率最高,为26.6%;植物连根收割后,湿地运行效果下降;其中TN去除率降至空白水平之下,而其他污染指标下降至略高于空白的水平。     

阴极液及底物浓度对AFB-MFC同步废水处理及产电性能影响

为了提高厌氧流化床微生物燃料电池（AFB-MFC）的性能,并为双室MFC寻找价廉、易得、无污染的阴极液,在曝气量16～24 L/h、温度（35±2）℃、回流量10.2 L/h、阴极底边距阴极室内底部17.3 cm、外电阻250 Ω、水力停留时间（HRT）14.0～14.9 h以及进水pH 7.81～8.37下,研究了阴极液及底物浓度对系统产电及废水处理性能的影响。结果表明,使用缓冲溶液、阳极室出水和自来水作阴极液时,自来水的产电性能最佳,阴极液种类不影响系统有机基质的去除。以自来水为阴极液时,阴极液pH及电导率随运行时间增加而增加,COD去除率为80.11%～89.29%,输出电压及功率密度开始随运行时间增加而增加,之后稳定在440～452 mV和48.40～51.08 mW/m²之间。增加底物浓度对COD去除率影响不大,而输出电压及功率密度随底物浓度增加而下降;底物COD浓度由3 307.09 mg/L增至9 520 mg/L时,COD去除率在85.77%～94.44%之间,输出电压及功率密度则分别由449 mV和50.40 mW/m²下降至406 mV和41.21 mW/m²。自来水作阴极液可避免二次污染及阴极液对阳极室微生物的影响,并得到高的产电能力。     

C/N和pH值对高温好氧反硝化菌产N2O的影响研究

以50℃高温、好氧条件下能进行高效好氧反硝化的菌株TAD1为研究对象,在不同C/N和pH值培养条件下,对其24 h的反硝化效率和反硝化过程中N2O的逸出量进行了研究。结果显示,C/N和pH值对菌株TAD1的反硝化效率和N2O产生量有明显影响.菌株TAD1最适宜的C/N为9,pH值为7,此时反硝化效率达到99.12%,N2O产生量仅为3.35×10-2 mg/L,N2 O转化率为0.045%,反硝化产物以氮气为主。另外,菌株TAD1不适宜在酸性条件下生长,pH值为6时反硝化效率为83.18%,N2O产生量为13.88×10-2 mg/L,是pH值为7时的4.14倍,是pH值为8时的5.07倍。     

污泥转移SBR工艺处理低浓度生活污水

污泥转移SBR工艺是一种通过内部污泥回流实现污泥在不同SBR隔室间转移,从而增加污泥利用效率,提高系统除污效能的新工艺。以设计规模为240 m3/d、处理低浓度生活污水的工艺系统为对象,研究了新工艺在不同泥转移量(污泥回流比)下的除污性能,并与系统以传统SBR方式运行的情况进行了对比。结果表明,新工艺可以有效提高SBR反应器的容积利用率;采用30%的污泥回流比进行污泥转移,新工艺的处理能力比传统SBR工艺提高近1/2,除磷效率从46%提升至85%。出水各项水质指标均能达到国家排放标准的要求。     

高分子量高纯度阳离子聚丙烯酰胺的合成

以丙烯酰胺与丙烯酰氧乙基三甲基氯化铵为单体,在复合引发剂的作用下,选择水溶液共聚法合成高分子量与高纯度阳离子型聚丙烯酰胺(CPAM)。实验表明,有机偶氮引发剂A用量0.5‰、氧化还原引发剂用量0.45‰、还原剂与氧化剂摩尔比2∶1、反应体系pH为4与反应时间5 h条件下,CPAM分子量为1 042万,且溶解性好。通过对聚合物残单含量影响因素添加剂用量、反应时间的研究,结果表明,添加剂EDTA和增溶剂D对残留AM含量影响小,而苯甲酸钠对聚合物残留AM的含量影响显著;延长反应时间至7 h,残单含量可降低至0.27%,CPAM的纯度高。通过与国内外3种同类型产品进行对比,结果表明,自制产品的分子量明显高于其他产品,且残单含量比国内产品降低了50%～75%。     

Fe3O4/SDS磁性纳米颗粒吸附水体中的Cd2+和Zn2+

一种新型纳米固相萃取吸附剂,由阴离子表面活性剂十二烷基磺酸钠(SDS)包裹在Fe3O4磁性纳米颗粒表面形成,用于吸附水溶液中的重金属离子。研究了吸附过程的主要影响因素(如SDS浓度、溶液pH等)以及解吸过程的最佳条件,并对其机理进行了初步的探讨。研究结果表明,共沉淀法制备的Fe3O4颗粒粒径分布均匀,平均粒径约为54 nm;SDS浓度为300 mg/L时,Fe3O4/SDS磁性纳米颗粒吸附Cd2+和Zn2+的能力最强;在一定浓度范围内,Fe3O4/SDS体系对Cd2+和Zn2+的吸附平衡数据符合Langmuir吸附等温方程,饱和吸附量分别为22.42 mg/g和13.95 mg/g。最终结果表明,Fe3O4/SDS磁性纳米颗粒具有较强磁分离能力和较好的吸附效果。     

菱镁矿尾矿制备高活性MgO的性能表征

菱镁矿尾矿经预处理后,在一定条件下制备高活性MgO。使用热重-差热分析仪,分析菱镁矿尾矿的分解温度,应用X射线衍射、SEM分析不同煅烧温度、保温时间对MgO晶体结构的影响,并根据Scherrer公式计算MgO晶粒的尺寸。通过电导率仪测定MgO水化电导率,分析不同条件下的MgO活性,探讨煅烧温度、保温时间、颗粒细度与MgO活性之间的关系。结果发现:煅烧温度在1 050℃,保温时间60 min时,菱镁尾矿完全分解,MgO活性最佳;煅烧温度越高,保温时间越长,MgO的活性越差;MgO颗粒细度越小,活性越高。