不同阴离子在生物质发酵产氢中的作用研究

为揭示不同阴离子在生物质发酵产氢中的作用规律,以混合菌群发酵产氢为研究对象,采用正交试验设计的方法考察了6种不同的阴离子及添加尿素对发酵产氢过程的影响.通过对不同阴离子浓度及相互关系对发酵产氢的影响的综合比较,获得以下结论:促进混合菌群发酵产氢的阴离子组成为:SO42-1.5 g·L-1,Cl-0 g·L-1,NO3-0 g·L-1,Mo7O246-0.1 g·L-1,C2O42- 1g·L-1,C6H5O73- 5g·L-1,(H2N)2CO 0 g·L-1;以PDB(马铃薯水解液)为基质发酵原料,H2最高含量和平均含量分别比对照组提高了21.4%和24.1%;平均产氢速率由对照组的36.79 mL·L-1·h-1提高到96.25 mL·L-1·h-1;氢气产率由对照组的0.76 mol·mol-1提高到1.17 mol·mol-1.研究同时证明,尿素对H2的产生具有显著的抑制作用,Mo7O246-则可促进混合微生物对原料的利用和转化;阴离子C2O42-和C6H5O73-的交互作用显著,说明两者同时使用可改善发酵产氢.从理论上对上述结果进行了分析探讨.     

微波-过氧化氢联合作用处理污泥的影响因素

作为一种新的污泥预处理技术,微波-过氧化氢联合作用处理污泥显示出高效、快速的优势.试验考察了3个主要参数:污泥浓度(定量H2O2和等比例H2O2/TSS投加)、微波功率和pH值对微波-过氧化氢联合作用处理污泥的影响.研究结果表明:①在H2O2定量投加(5000mg·L-1)时,当污泥浓度超过22g·L-1,溶出COD没有显著增加;在H2O2与TSS等比例投加条件下,COD溶出与污泥浓度呈线性关系;②微波功率在200～1000W范围内不影响污泥处理效果;③在微波-过氧化氢联合作用处理污泥时,污泥溶解比例随着污泥初始pH值的提高而增加.     

Cd uptake in rice cultivars treated with organic acids and EDTA

A pot experiment was conducted to examine the activity of antioxidant enzymes, the content of malondialdehyde (MDA), proline and protein, and Cd uptake in different rice cultivars exposed to Cd (0, 1 and 5 mg/kg) in the presence of organic acids and ethylenediamine tetraacetic acid (EDTA). The results showed the increase in activity of dismutase (SOD), contents of proline and protein but a decline in activities of peroxidase (POD) and catalase (CAT), and MDA content for cultivars Xiushui63 and IIyou527. The...     

Reinvestigation of the Henry’s law constant for hydrogen peroxide with temperature and acidity variation

Hydrogen peroxide is not only an important oxidant in itself;it also serves as both sink and temporary reservoir for other important oxidants including HOx(OH and HO2) radicals and O3 in the atmosphere.Its partitioning between gas and aqueous phases in the atmosphere,usually described by its Henry's law constant(KH),significantly influences its role in atmospheric processes.Large discrepancies between the KH values reported in previous work,however,have created uncertainty for atmospheric modelers.Based on our newly developed online instrumentation,we have re-determined the temperature and acidity dependence of KH for hydrogen peroxide at an air pressure of(0.960 ± 0.013) atm(1 atm = 1.01325 × 105 Pa).The results indicated that the temperature dependence of KH for hydrogen peroxide fits to the Van't Hoff equation form,expressed as lnKH = a/T-b,and a =-ΔH/R,where KH is in M/atm(M is mol/L),T is in degrees Kelvin,R is the ideal gas constant,and ΔH is the standard heat of solution.For acidity dependence,results demonstrated that the KH value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level(from pH 7 to pH 1).Combining the dependence of both temperature and acidity,the obtained a and b were 7024 ± 138 and 11.97 ± 0.48,respectively,ΔH was(58.40 ± 1.15) kJ/(K·mol),and the uncertainties represent σ.Our determined KH values for hydrogen peroxide will therefore be of great use in atmospheric models.     

阻抑催化动力学光度法测定水体中的痕量镍

研究了在pH9.2硼砂介质中,镍(II)对过氧化氢氧化溴甲酚紫褪色反应具有阻抑作用,聚乙二醇-200(PEG-200)对此反应体系有活化作用,据此建立了阻抑动力学光度法测定痕量镍(II)的新方法。试验考察了反应介质种类和用量、活化剂种类和用量、反应温度、反应时间、共存组分等因素的影响,确定了最佳试验条件。该方法的测定波长为590nm;活化剂为PEG-200;反应温度为沸水浴;反应时间为14min;线性范围为1.7×10-6g/L～1.4×10-4g/L;检出限为1.7×10-6g/L。所建方法用于环境水体中痕量镍(II)的测定,最大相对标准偏差为3.27%,加标回收率为95.5%～104.5%;所建方法与火焰原子吸收光谱法进行了对比试验,方法相对误差小于6.50%。     

水稻秸秆厌氧发酵制氢技术研究

以水稻秸秆为研究原料,用牛粪为接种物,采用稀硫酸预处理方法来提高秸秆纤维素的降解率,从而提高其发酵产氢的能力,并且进一步考察了发酵初始pH、发酵温度、牛粪与秸秆的质量比和底物浓度四个条件对发酵产氢的影响。实验结果表明:在接种100g/L牛粪的条件下,以1.8%的硫酸加热30min预处理秸秆产氢效果最佳,为19.64mL/gTS,是未经过预处理的秸秆产氢量(0.1mL/gTS)的196倍,粗纤维含量由未处理前的36.7%下降到酸处理后的31.5%。在pH8.0、温度为37℃、牛粪与秸秆质量比为2.5∶1、底物浓度为50g/L时的产氢效果最好,累计产氢量为29.14mL/gTS,此时生物气中没有检测到甲烷气体,氢气浓度达到63.88%。     

油田含硫化氢天然气无害化治理技术

重点介绍了生物法治理油田储油罐逸散的含硫化氢天然气的工程应用经验。     

Modeling forest floor contribution to phosphorus supply to maritime pine seedlings in two-layered forest soils

The quantitative contribution of the forest floor to P nutrition of maritime pine seedlings was experimentally determined by Jonard et al. (2009) in a greenhouse experiment using the radio-isotopic labeling. To extend the results of the experiment on a known mineral soil, a modeling approach was developed to predict P uptake of maritime pine seedlings growing in a mineral soil covered with a forest floor layer. The classical nutrient uptake model based on the diffusion/mass-flow theory was extended to take into account mineralization of P in dead organic matter, microbial P immobilization and re-mineralization and P leaching. In addition, the buffer power characterizing the P retention properties of the mineral soil was allowed to vary with time and with the P-ion concentration in solution. To account for increasing root competition with time, a moving boundary approach was implemented. According to the model, the forest floor contributed most of the P supply to the seedlings (99.3% after 130 days). Predicted P uptake was consistent with observed P uptake and modeling efficiency was 0.97. The uptake model was then used to evaluate the impact of the P retention properties of the mineral soil on the contribution of the forest floor to P uptake. Simulations showed that the contribution of the forest floor was much lower in the quasi non-reactive soil (45.7%) but rapidly increased with soil P reactivity.     

水稻根系吸收砷的动力学特征及硅的缓解机制（Uptake Kinetics of Arsenic Species in Two Genotypes of Rice Plants and Mitigatory Mechanism of Silicon）

采用室内模拟的方法,研究了两种基因型水稻(硅突变体和野生型)根系吸收As的动力学特征以及Si对水稻吸收As的影响.结果表明,两种基因型水稻根系对As(III)和As(V)的吸收均可以用Freundlich模型较好地模拟.外源Si的加入可显著降低水稻根系对As(III)和As(V)的吸收.在20μmol·L-1As处理下,与不加Si处理相比,加1.0mmol·L-1Si处理导致水稻根系吸收As(III)和As(V)分别降低94.1%和92.2%(野生型);74.4%和90.2%(突变体).在100μmol·L-1As处理下,水稻根系吸收As(III)和As(V)则分别降低64.5%和91.2%(野生型);76.1%和90.6%(突变体).     

亚热带丘陵区绿狐尾藻人工湿地处理养猪废水氮磷去向

以亚热带丘陵区为研究区,采取野外定位观测的研究方法,选取耐高氮（N）、磷（P）的绿狐尾藻为湿地植物,建立稻草基质池+6级绿狐尾藻表面流湿地系统,湿地总面积1597 m²,水力负荷0.06~0.14 m·d^-1,水力停留时间31 d,研究此湿地系统对养猪废水（NH₄⁺-N：535.4~591.09 mg·L^-1、TN：682.09~766.96 mg·L^-1、TP：57.73~82.29 mg·L^-1和COD：918.4~1940.43 mg·L^-1）的治理效果,旨在为亚热带高负荷猪废水的生态治理提供参数依据.结果表明,湿地系统对NH₄⁺-N、TN、TP和COD的平均去除率为97.4%、97.1%、91.0%和90.2%,其中以CW1累积贡献率最大（37.3%、38.4%、43.3%和27.4%）.植物N、P吸收量在23.87~79.96 g·m^-2和5.34~18.98 g·m^-2之间,占湿地N、P去除量的19.1%和20.2%;底泥N、P吸附量在19.17~56.62 g·m^-2和10.59~26.62 g·m^-2之间,占去除量的19.8%和61.7%.湿地N、P去除率与影响因子间的关系表明,环境因子解释了湿地N、P去除率的79.9%和70.1%.其中,DO是湿地系统N去除的主要因子,底泥P吸附是P去除的关键.