化工原料及制药中间体中二苯胺亚硝化衍生的极谱法测定

报道一种经亚硝化后用极谱定量二苯胺的极谱测定方法。在０．２ｍｏｌ／ＬＨＡｃ－０．０２５ｍｏｌ／ＬＨ＿２ＳＯ＿４－４×１０￣（－６）ｍｏｌ／ＬＮａＮＯ＿２底液中，二苯胺的亚硝化产物有一良好的极谱还原波，峰电位为－０．６１Ｖ（ｖｓ，ＳＣＥ），峰高与二苯胺浓度在２×１０￣（－７）～１×１０￣（－５）ｍｏｌ／Ｌ范围内有线性关系（ｒ＝０．９９９９）。     

近岸、河口缺氧区域的主要生物地球化学耗氧过程

近岸、河口区的缺氧问题正逐步发展为全球性的重大生态环境问题,探究缺氧的形成、变化趋势及其控制机理科学意义显著,也是区域环境保护与治理决策的科学基础.珠江是中国第二大河,其主要入海口之一的虎门及其上游水域的表层溶解氧浓度经常小于3 mg/L,甚至低达0.5～1 mg/L,该低氧水域面积超过70 km^2.本文以珠江口缺氧区域为主,综述了近岸、河口区的主要生物地球化学耗氧过程,提出在分析近岸、河口区的缺氧问题时必须综合考虑有机物耗氧分解与硝化作用,缺氧水域同时也是CO2、N2O、CH4等生源温室气体的重要源地.     

三江平原典型草甸小叶章湿地土壤的反硝化作用

选择三江平原典型草甸小叶章湿地土壤（草甸沼泽土）为研究对象,采用厌氧淹水培养法,研究了不同土层的反硝化率、反硝化能力及反硝化速率。结果表明,不同土层的反硝化率均随培养时间延长而增加,0～30cm土层的反硝化率较高,30cm以下土层较低且相近;不同土层的氖损失贡献率在不同阶段具有明显的时空分异特征,0～30cm土层的氮损失贡献率较高,介于52．39％和57．91％之间;不同土层的反硝化速率与培养时间均符合一阶指数衰减模型（R2≥0．97）,上层土壤的反硝化速率明显高于下层土壤。不同土层的反硝化率和反硝化速率与土壤理化性质密切相关,反硝化细菌的剖面分布可能对其具有重要影响。图3,表4,参24。     

SBR反应器实现半亚硝化的启动策略

由于碳源不足,传统脱氮工艺难以处理高NH4+-N低碳氮比废水,采用短程硝化与厌氧氨氧化相结合的工艺可以处理此类废水,而半亚硝化是上述组合工艺的先决条件.采用低溶解氧和半碱度为启动策略,实现SBR反应器的半亚硝化作用,以期为后续厌氧氨氧化反应器提供合适进水水质.实验结果表明:水温(26±1)℃,控制初始碱度和NH4+-N的摩尔比为1,进水pH保持7.5±0.1,溶解氧为(0.8±0.2)mg/L的条件下,可将NO2--N累积率维持在95%,且出水中NO2--N和NH4+-N浓度相近,而NO3--N质量浓度低于5mg/L,反应器成功启动.进水化学需氧量(COD)对半亚硝化效果几乎没有影响.一个运行周期内三氮及COD的变化趋势说明,采用半碱度策略控制半亚硝化进程是可行的,能够保证出水NO2--N/NH4+-N摩尔比约为1.     

三峡库区消落带土壤N2O排放和反硝化影响因子分析

应用乙炔抑制培养法研究了水分、温度、氮源和碳源等影响因子对三峡库区腹地消落带土壤N2O排放和反硝化作用的影响,并与原位试验结果进行了比较。结果表明,土壤含水量是影响土壤N2O排放和反硝化作用的重要因素,反硝化速率随着土壤充水孔隙度（WFPS）的增加而增大,土壤反硝化速率最大值出现在土壤WFPS为100%时,N2O排放速率最大值出现在土壤WFPS为60%时。温度在10～40 ℃范围内,土壤N2O排放速率和反硝化速率随着温度的升高而增大,相关性分析表明,土壤N2O排放速率和反硝化速率均与温度呈显著正相关。外加氮源为NO -3-N时,反硝化速率随氮源量的增加有减小的趋势,过多的硝态氮抑制反硝化作用;而添加易被微生物利用的葡萄糖作为碳源则会明显提高土壤反硝化速率,当每千克土加入碳源量为240 mg时反硝化速率最大。     

一株反硝化真菌的分离鉴定及其对生物塔脱氮效率的影响

国内外对细菌的作用及作用机制研究较多,而对真菌的作用及机制研究较少.为了提高NO,NO_x的脱除效率,本文对脱氮塔生物膜中的反硝化真菌进行了分离、纯化及鉴定,通过摇瓶实验研究了反硝化真菌对NO_3~-的作用特征,最后在脱氮塔中投加了分离的反硝化真菌纯菌株扩大培养液,研究了其对NO_x脱除效率的影响,还对脱氮塔内真菌的群落结构进行了高通量测序分析.实验结果表明:经过真菌形态特征和脱氮(NO_3~-)特性研究及ITS序列测定分析,将3LNB菌株鉴定为镰刀菌的腐皮镰刀菌Fusarium solani.高通量测序分析结果证明了脱氮塔内确实存在镰刀菌属的腐皮镰刀菌Fusarium solani.在NO_3~-—N浓度高达10.01g/L的条件下,实验共10d,细菌反硝化组反硝化率为5.6%,其脱除效率为0.56g/L;真菌3LNB菌株的反硝化率能达到15.1%,其脱除效率为1.51g/L.实验室实验证明3LNB菌株对NO_3~-具有较强的反硝化能力.将3LNB纯菌株扩大培养液400mL(4%)投加到脱氮塔中,NO,NO_x的平均脱除率分别提高了5.12%,5.36%.脱氮塔净化实验证明3LNB培养液能强化微生物对NO,NO_x的脱除效能,这可能主要与腐皮镰刀菌等真菌细胞存在细胞色素P450nor有关.     

Population dynamics and spatial distribution of microbial species in multispecies biofilms under the action of direct electric current

The metabolism, population dynamics and spatial distribution of nitrifying bacteria and heterotrophs in biofilms under the action of direct electric current were investigated by using the micro-slicing technique. The nitrification rate of nitrifying bacteria was severely inhibited by a current over 10 Am^-2 at lower C/N ratios. Compared to heterotrophs, the nitrifying bacteria in the surface biofilms were severely inhibited, resulting in a significant decrease in bacterial density. An increase in current density narrowed the less current-sensitive inner biofilm region, and in addition the density of NO2-oxidizers decreased more significantly than that of NH4-oxidizers in the surface biofilms probably due to electrochemical reactions at the anode. However, the effect of current on both the population dynamics and the spatial distribution of the microbial species was less significant at larger C/N ratios.     

Effects of nitrogen sources and glucose on the consumption of ethylene and methane by temperate volcanic forest surface soils

There is limited knowledge with regard to the consumption of ethylene (C2H4) and methane (CH4) in volcanic forest soils containing low microbial carbon-to-organic carbon ratio, and to the responses of both consumptions to nitrogen and carbon additions. Temperate volcanic forest surface soils under three forest stands (e.g. Pinus sylvestris L., Cryptomeria japonica and Quercus serrata) were used to compare CH4 and C2H4 consumption by forest soils, and to study the effects of nitrogen sources and glucose on both consumptions. There was a good parallel between CH4 and C2H4 consumption by for- est soils, but mineralization reduced CH4 consumption rather than C2H4 consumption in forest soils, particularly in a Pinus forest soil. The stimulatory effect of glucose addition on both CH4 and C2H4 consumption by forest soils was increased by increasing the pre-incubation period after glucose addi- tion, and a largest stimulation occurred in the Pinus forest soil. The addition of KNO3-N at the rate of 100 μg·g1 significantly reduced the consumptions of both C2H4 and CH4 by forest soils (P≤0.05). In the presence of urea plus dicyandiamide, the consumption rates of C2H4 and CH4 by forest soils were higher than those in the KNO3-N and urea-N treated soils at the same N rate (P≤0.05), but were similar to those of the control. Hence, under experimental conditions, there was a strong inhibitory effect of NO3 rather than NH4 addition on the CH4 and C2H4 consumption in these forest soils. When amount of the added NO3-N increased up to more than 2―3 times the soil initial NO3-N concentrations, both C2H4 and CH4 consumption rates were reduced to 10%―20% of the rates in soils without nitrate addition. By comparing the three forest stands, it was shown that there was a smallest effective concentration of the added nitrate that could inhibit C2H4 and CH4 consumption in the Pinus forest soil, which indicated that C2H4 and CH4 consumption of the soil was more sensitive to NO3-N addition.     

近岸、河口缺氧区域的主要生物地球化学耗氧过程

近岸、河口区的缺氧问题正逐步发展为全球性的重大生态环境问题,探究缺氧的形成、变化趋势及其控制机理科学意义显著,也是区域环境保护与治理决策的科学基础.珠江是中国第二大河,其主要入海口之一的虎门及其上游水域的表层溶解氧浓度经常小于3 mg/L,甚至低达0.5～1 mg/L,该低氧水域面积超过70 km2.本文以珠江口缺氧区域为主,综述了近岸、河口区的主要生物地球化学耗氧过程,提出在分析近岸、河口区的缺氧问题时必须综合考虑有机物耗氧分解与硝化作用,缺氧水域同时也是CO2、N2O、CH4等生源温室气体的重要源地.     

温度、光照强度和盐度对近海养殖水体硝化作用的影响

温度;光照强度;盐度;近海;养殖;水体;硝化作用