Tailoring the simultaneous abatement of methanol and NOx on Sb-Ce-Zr catalysts via copper modification

● Cu addition enhances CH₃OH oxidation and alleviates its inhibitory effect on SCR. ● Cu addition improves the activation of SCR reactants in the presence of methanol. ● Damaged structure by more Cu addition decreases specific surface area and acidity. ● Excessive Cu addition would lead to the narrowing of SCR temperature window. Simultaneously removal of NO_x and VOCs over NH₃-SCR catalysts have attracted lots of attention recently. However, the presence of VOCs would have negative effect on deNO_x efficiency especially at low temperature. In this study, copper modification onto Sb_0.5CeZr₂O_x (SCZ) catalyst were performed to enhance the catalytic performance for simultaneous control of NO_x and methanol. It was obtained that copper addition could improve the low-temperature activity of both NO_x conversion and methanol oxidation, where the optimal catalyst (Cu_0.05SCZ) exhibited a deNO_x activity of 96% and a mineralization rate of 97% at 250 °C, which are around 10% higher than that of Cu free sample. The characterization results showed that copper addition could obviously enhance the redox capacity of the catalysts. As such, the inhibition effect of methanol incomplete oxidation on NO adsorption and NH₃ activation were then lessened and the conversion of surface formamide species were also accelerated, resulting in the rising of NO_x conversion at low temperature. However, excessive copper addition would damage the Sb-Ce-Zr oxides solid solution structure owing to Cu-Ce strong interactions, decreasing the surface area and acidity. Meanwhile, due to easier over-oxidation of NH₃ with more Cu addition, the temperature window for NO_x conversion would become quite narrow. These findings could provide useful guidelines for the synergistic removal of VOCs over SCR catalyst in real application.     

纳米晶体表层钛阳极的制备及其在废水处理中的应用

采用溶胶-凝胶法制备了纳米晶体表层钛阳极,并表征了该钛阳极的形貌。实验结果表明：纳米晶体表层钛阳极表面平整,裂隙很少,且提高了电流效率;制作的中间涂层,在保护钛板、节省贵金属的同时使钛阳极涂层具有一定的梯度结构,增加了涂层的结合力,使该钛阳极具有较长的使用寿命,最佳条件下可使用15a以上;纳米晶体表层钛阳极处理硝基苯废水的最佳实验条件为：pH=2,每平方厘米纳米晶体表层钛阳极处理12mL废水,电流密度10mA／cm^2。在此最佳条件下,在较低耗电量（每吨废水耗电量低于6kW·h）的情况下硝基苯去除率大于98％。     

有机化合物水中溶解度的测定与估算

本文介绍用摇瓶法、产生柱法和动态联柱高效液相色谱法等方法测定有机化合物在水中溶解度的研究方法,同时给出了某些农药、硝基多环芳烃和氯苯类化合物的水中溶解度的实验数值.     

稀土离子对超氧阴离子自由基生成的抑制作用

利用肾上腺素在碱性条件下自氧化产生超氧阴离子自由基（O^.-2）的性质,研究了稀土硝酸盐对生成O^.-2的抑制作用。稀土硝酸盐与超氧化物歧化酶（SOD）具有相似的性质,对肾上腺素自氧化生成的O^.-2有明显的抑制作用。抑制率在16．3％－78．4％之间,而且体系中稀土硝酸盐的浓度与其对O^.-2的抑制率之间有明显的剂量效应关系。     

土壤中结合态苯氧羧酸类除草剂的测定

利用超临界ＣＯ２流体萃取的方法提取２甲４氯(ＭＣＰＡ),２,４－Ｄ和除草醚在三种土壤中的结合残留．结果表明,在培养２００ｄ的时间内,ＭＣＰＡ的结合残留量为１．０ｌ－５．１２ｍｇ·ｋｇ－１,占添加总量的２．０－１０．１%;２,４－Ｄ的结合残留量为０．２４－２．６５ｍｇ·ｋｇ－１,占添加总量的０．５－５．３%;除草醚的结合残留量为６．５３－１９．３０ｍｇ·ｋｇ－１,占添加总邑的１２．９—３８．２%．农药结合态与游离态含量的比值随时间的延长而增加．     

紫外光作用下氯酚的矿化程度比较

有关氯酚污染物光化学降解的研究,已有报道。ＨｕａｎｇＣＰ的工作较有系统性,他研究了四类深度化学氧化过程,检测指标是氯酚浓度。本文研究了在紫外光以及其它因素作用下,氯酚混合溶液的矿化程度,以溶液总有机磷浓度ＴＯＣ作为指标。所得结论,对于含有氯酚废水的治理,具有指导意义;对于难降解     

Seed priming with brassinosteroids alleviates aluminum toxicity in rice via improving antioxidant defense system and suppressing aluminum uptake

Environmental Science and Pollution Research - Brassinosteroids (BRs) are growth-promoting hormones that exhibit high biological activities across various plant species. BRs shield plants against...     

Assessment of GC–MS response of selected pesticides in apple matrices related to matrix concentration

A uniform analyte response is required for GC–MS analysis in order to obtain acceptable quantitative results. The response of pesticides in complex matrices is susceptible to variation due to the interactions of co-extractives, both with pesticides or with GC–MS system. This study was conducted to determine the magnitude of the interactions, called matrix effect, and their behavior with the matrix dilution. The response of pyrimethanil (4,6-dimethyl-N-phenylpyrimidin-2-amine), cyprodinil (4-cyclopropyl-6-methyl-N-phenylpyrimidin-2-amine), trifloxystrobin (methyl-(2Z)-2-methoxyimino-2-[2-[[(E)-1-[3(trifluoromethyl)phenyl]ethylidene amino]oxymethyl]phenyl]acetate) and bifenthrin(2-methyl-3-phenylphenyl)methyl-3-[(Z)-2-chloro-3,3,3-trifluoroprop-1-enyl]-2,2-dimethylcyclopropane-1-carboxylate), used in apple crops protection, was evaluated in different concentrations of peel and flesh extracts of Granny Smith, Golden Delicious and Demi Rouge, selected as representatives of different matrix types. The matrix effect ranged from ?0.05 to 146.14%, depending on matrix type and pesticide. The highest response variation was observed in extracts of Granny Smith—an enhancement in flesh and suppression in peel extract. With the dilution, the matrix effect decreased with different magnitudes, but for Granny Smith peel extract an inverted effect was observed. The presence of the matrix effect in GC–MS pesticides analysis was obvious, requiring the application of matrix-matched calibration in quantification procedures for each variety, with calibration standards matched by the matrix concentration.     

APPLICATION OF TABU SEARCH TO GROUND WATER PARAMETER ZONATION1

ABSTRACT: The spatial distribution of hydrogeologic parameter is an important issue in ground water simulation. One of the methods is to divide an area into several zones such that parameters are assumed to be constant within zone. The purpose of this study is to apply Tabu Search (TS) to find the best zonation of parameters that can result in the best ground water simulation. The initial zonation can be determined as the Thiessen method, and then zonation is optimized by T.S. The mean square error between simulated and observed hydraulic heads was used as the objective function. A designed confined aquifer with known zonation was used as an example to test the proposed method. Results indicated that Tabu Search can locate the optimal zonation successfully and avoid being trapped by local optimal zonations. Besides this, four other arbitrary initial zonations can be directed to the optimal zonation by TS, which proves the robustness of the proposed method. The method proposed in this study is feasible and expected to work well in the field problems with sufficient sampling of concerned parameters.