NaOH溶液吸收CO2的试验研究

为了满足国际海事组织对船舶CO2排放的要求,建立了一种针对船舶尾气CO2的循环吸收系统,利用NaOH溶液吸收CO2.NaOH溶液完成第一步吸收反应后在第二步反应中被还原,从而可以循环利用.分析了初始反应温度、NaOH浓度及溶液中的Na2CO3对CO2吸收率的影响,并计算了循环反应中NaOH的再生率和CaO的过量系数.结果表明,CaO过量系数为1.2时对CO2固化效果最佳,此时NaOH溶液再生率达79.31％.研究表明,NaOH溶液吸收船舶尾气中CO2的循环系统效率高、成本低.     

燃煤飞灰负载型碱基CO2吸收剂再生试验研究

采用热重分析方法研究了燃煤飞灰负载型碱基吸收剂脱除CO2的再生反应特性,同时介绍了燃煤飞灰负载型碱基吸收剂的制备方法,即向燃煤飞灰中添加KHCO3和黏结剂制备得到CO2干式吸收剂.针对不同升温速率和反应终温对吸收剂再生反应特性的影响规律进行试验分析,采用热分析动力学方法确定了吸收剂再生反应特性参数.结果表明:KHCO3负载于燃煤飞灰后,有利于提高颗粒的比表面积;在氮气气氛下,再生反应表观活化能为24～60 kJ/mol;反应速率和终温是再生反应的重要影响因素;当升温速率为10℃/min时,所需活化能最低,为24.8 kJ/mol,再生性能最好;再生反应的起始温度为100～ 150 ℃,终止温度为225～275℃.     

玉米叶吸附剂对水溶液中Pb2+的吸附性能研究

研究了玉米叶对水溶液中Pb2+的吸附性能,借助正交和单因素试验探讨各因素对吸附率的影响,利用红外光谱研究吸附机理,并采用Langmuir、Freundlich和Temkin模型对吸附数据进行拟合.结果表明:金属初始质量浓度和体系pH值是影响吸附的重要因素;玉米叶吸附铅离子的最佳pH值为5.0,金属质量浓度和吸附剂投加量最佳比值为80 mg/L:0.170 g,在25℃时玉米叶对铅离子的吸附较快,180min后达到吸附平衡;吸附数据更加符合Freundlich和Temkin等温吸附模型,由Langmuir等温吸附模型可知玉米叶最大吸附量为103.266mg/g,吉布斯自由能△Ge为负值,该过程吸热且自发进行.红外光谱分析表明,参与作用的官能团为羟基、羧基、酰胺或脂肪族C-x(x代表Cl、Br、I).     

空气氧化解吸NO络合吸收产物试验研究

Fe(Ⅱ) EDTA易被氧化为对NO无吸收能力的Fe(Ⅲ)EDTA,为实现Fe(Ⅱ)EDTA的循环使用,提出了Fe(Ⅱ)EDTA络合吸收-空气氧化解吸-铁屑还原再生组合脱除NO新工艺.采用空气氧化解吸络合吸收产物Fe(Ⅱ) EDTA (NO)中NO的方法,研究了温度及压力对Fe(Ⅱ)EDTA(NO)空气氧化解吸过程的影响.结果表明,0.4 MPa、333K为较优的解吸条件.该工艺可循环脱除NO,成本低、效率高,能有效回收NO2资源.     

丙二酸二(2-(2,3-二羟基苯甲酰胺)乙基)酯的合成与螯合性能研究

用2,3-二羟基苯甲酸经羟基保护、酰胺化、酯化和去保护4步反应,生成一种新型的四齿丙二酸二(2-(2,3-二羟基苯甲酰胺)乙基)酯配体.采用傅里叶变换红外光谱(FT-IR)、紫外-可见光谱(UV-Vis)、核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)和质谱(MS)对其结构进行了表征.在中性pH值条件下,研究了这种配体对铀酰离子的络合能力.结果表明,丙二酸二(2-(2,3-二羟基苯甲酰胺)乙基)酯配体与铀酰离子的螯合常数为23.2.     

单斜相纳米氧化锆基低温SCR催化剂脱硝机制研究

以纳米m-ZrO2为载体,用浸渍法制备出MnOx-CeO2/m-ZrO2催化剂,考察反应温度、活性组分负载量对催化剂NH3-SCR脱硝活性影响,探讨催化剂表面织构特征,分析催化剂脱硝活性机制.结果表明,在低温脱硝温度范围,提高反应温度、增加活性组分负载量,有利于催化剂脱硝效率的增加.110℃时,2.5%MnOx-CeO2/m-ZrO2脱硝效率为55.5%,15%MnOxCeO2/m-ZrO2脱硝效率达93.5%.XRD、BET、XPS、H2-TPR表征结果表明,催化剂表面具有良好的氧化还原能力,表面织构对脱硝反应有利.NH3-TPD测试显示,MnOx-CeO2/m-ZrO2催化剂的脱硝反应机制为:NH3吸附在催化剂表面的Lewis酸性位和Brnsted酸性位上,通过反应生成相应中间产物NH2NO或NH4NO2,中间产物进一步分解最终转变为N2和H2O;催化剂总脱硝反应效率中,在Lewis酸性位上的脱硝反应占比较大.     

植被收割对滨海湿地沉积物中CO_2和N_2O释放的影响

为了揭示冬季滨海湿地植被收割对其沉积物中温室气体释放的影响,以长江入海口典型滨海湿地——崇明东滩为研究对象,观测季节性(冬季)植被收割(分别于收割后第0天、第10天、第30天、第60天采样)与不收割条件下芦苇(Phragmites australis)、米草(Spartina alterniflora)、芦苇-米草交互带和光滩沉积物中CO2与N2O的释放特征.结果表明:1米草和芦苇-米草交互带植被收割并未增加沉积物中CO2的释放(P0.05),但芦苇收割可能会增加N2O的释放(P0.05),说明植被收割对湿地沉积物中CO2和N2O释放的影响与植被类型密切相关.2与芦苇带相比,米草和芦苇-米草交互带沉积物中CO2累积释放量分别高出12%~57%和17%~43%,但芦苇植被覆盖下沉积物中N2O累积释放量分别比二者高出11%~81%和8%~95%.可见,米草和芦苇-米草交互带沉积物碳的呼吸损失明显高于芦苇带,但芦苇植被覆盖下沉积物中N2O逸失量相对较高.34种植被类型下,沉积物中N2O累积释放量为0.1~0.4 mg/kg,CO2累积释放量则高达1 024~2 645 mg/kg.因此,冬季滨海湿地植被收割不会显著增加N2O的温室效应,但选择性收割米草有望减少沉积物碳的呼吸损失.     

Applying a new method for direct collection,volume quantification and determination of N2 emission from water

The emission of N2 is important to remove excess N from lakes, ponds, and wetlands. To investigate the gas emission from water, Gao et al.(2013) developed a new method using a bubble trap device to collect gas samples from waters. However, the determination accuracy of sampling volume and gas component concentration was still debatable. In this study, the method was optimized for in situ sampling, accurate volume measurement and direct injection to a gas chromatograph for the analysis of N2 and other gases. By the optimized new method, the recovery rate for N2 was 100.28% on average; the mean coefficient of determination(R2) was 0.9997; the limit of detection was 0.02%. We further assessed the effects of the new method, bottle full of water, vs. vacuum bag and vacuum vial methods, on variations of N2 concentration as influenced by sample storage times of 1,2, 3, 5, and 7 days at constant temperature of 15°C, using indices of averaged relative peak area(%) in comparison with the averaged relative peak area of each method at 0 day.The indices of the bottle full of water method were the lowest(99.5%–108.5%) compared to the indices of vacuum bag and vacuum vial methods(119%–217%). Meanwhile, the gas chromatograph determination of other gas components(O2, CH4, and N2O) was also accurate. The new method was an alternative way to investigate N2 released from various kinds of aquatic ecosystems.     

Enhanced bio-decolorization of 1-amino-4-bromoanthraquinone-2-sulfonic acid by Sphingomonas xenophaga with nutrient amendment

Bacterial decolorization of anthraquinone dye intermediates is a slow process under aerobic conditions. To speed up the process, in the present study, effects of various nutrients on 1-amino-4-bromoanthraquinone-2-sulfonic acid (ABAS) decolorization by Sphingomonas xenophaga QYY were investigated. The results showed that peptone, yeast extract and casamino acid amendments promoted ABAS bio-decolorization. In particular, the addition of peptone and casamino acids could improve the decolorization activity of strain QYY. Further experiments showed that L-proline had a more significant accelerating effect on ABAS decolorization compared with other amino acids. L-Proline not only supported cell growth, but also significantly increased the decolorization activity of strain QYY. Membrane proteins of strain QYY exhibited ABAS decolorization activities in the presence of L-proline or reduced nicotinamide adenine dinucleotide, while this behavior was not observed in the presence of other amino acids. Moreover, the positive correlation between L-proline concentration and the decolorization activity of membrane proteins was observed, indicating that L-proline plays an important role in ABAS decolorization. The above findings provide us not only a novel insight into bacterial ABAS decolorization, but also an L-proline-supplemented bioaugmentation strategy for enhancing ABAS bio-decolorization.     

Applying a new method for direct collection, volume quantification and determination of N2 emission from water

The emission of N₂ is important to remove excess N from lakes, ponds, and wetlands. To investigate the gas emission from water, Gao et al. (2013) developed a new method using a bubble trap device to collect gas samples from waters. However, the determination accuracy of sampling volume and gas component concentration was still debatable. In this study, the method was optimized for in situ sampling, accurate volume measurement and direct injection to a gas chromatograph for the analysis of N₂ and other gases. By the optimized new method, the recovery rate for N₂ was 100.28% on average; the mean coefficient of determination (R²) was 0.9997; the limit of detection was 0.02%. We further assessed the effects of the new method, bottle full of water, vs. vacuum bag and vacuum vial methods, on variations of N₂ concentration as influenced by sample storage times of 1, 2, 3, 5, and 7 days at constant temperature of 15°C, using indices of averaged relative peak area (%) in comparison with the averaged relative peak area of each method at 0 day. The indices of the bottle full of water method were the lowest (99.5%-108.5%) compared to the indices of vacuum bag and vacuum vial methods (119%-217%). Meanwhile, the gas chromatograph determination of other gas components (O₂, CH₄, and N₂O) was also accurate. The new method was an alternative way to investigate N₂ released from various kinds of aquatic ecosystems.