SGO改性复合纳滤膜的制备及分盐性能

近年来,水资源短缺,水源污染严重,国家对水处理末端的资源化利用提出了更高的要求,分盐过程也受到越来越多的关注.纳滤膜表面通常带有电荷,可以选择性地透过不同价态的离子.基于纳滤膜表面电荷特性不同,为很好地实现盐的分离,将制备的带有磺酸基团的氧化石墨烯引入到纳滤膜材料中,采用界面聚合法,制备了SGO改性复合纳滤膜. Zeta电位分析表明所制备的复合纳滤膜表面的电荷比不添加SGO的纳滤膜更负;红外光谱分析中酯基基团特征峰的出现表明磺酸基团参与了聚合反应; SEM结构表面,膜表面出现了明显的图灵结构,在0. 2 MPa压力下,纯水通量可达45. 85 L·(m~2·h)-1,对Na2SO4截留率为98. 23%,对Na Cl截留率为24. 93%,10 h运行可以很好地实现对SO_4~(2-)、Cl~-的有效分离,可实现盐的资源化回收.     

烃基酚类化合物结构与毒性关系研究

有机化合物通常由电性各异的氢、碳、氮、氧、硫及卤素等原子以共价键结合而成,从分子的三维空间结构出发,按照不同类型原子之间电性相互作用得到一种分子结构表达方法--三维分子电性相互作用矢量(three dimensional molecular electronegativity interaction vector,3D...     

Regioselective oxidation of tetracycline by permanganate through alternating susceptible moiety and increasing electron donating ability

Permanganate has attracted much attention in wide range of chemistry and particularly in degradation of environmental pollutants. However, few studies have discussed the feature of regioselective reactivity of permanganate with specific moiety of the target compound. Herein, we studied the reaction between permanganate and tetracycline that is an emerging micropollutant with different species containing several electron-rich groups. The second-order rate constants increased from 6.0 to 9.0 and could be quantitatively modeled by considering the speciation of both reactants, yielding k_TC⁰?=?11.7 (mol/L)^?1?sec^?1, k_TC^??=?35.7 (mol/L)^?1?sec^?1, k_TC^2??=?43.1 (mol/L)^?1?sec^?1 for individual reaction channels. Degradation products were then identified as the hydroxylated and demethylated compounds. The result suggested a rate-limiting step of simple hydroxylation at the phenolic and/or alkene moieties, while the demethylation should be caused by the unavoidably formed manganese oxide via single electron oxidation. This is supported by the DFT calculation, indicating the primary oxidation of phenolic group of TC⁰ with activation barrier of 44.5?kcal/mol and of alkene group of TC^? and TC^2? with activation barriers of 44.0 and 43.4?kcal/mol, respectively. This is in agreement with the experimental results, implying the alternation of regioselectivity associated with the deprotonation process. The result was further supported by performing the Fukui function and electrostatic potential analysis, reflecting the more probable site and better electron donating tendency beneficial to the permanganate oxidation.     

碱金属改性Pd/γ-Al2O3催化剂三效性能的研究

考察了碱金属对氧化铝负载钯催化剂的改性作用,发现钾的作用最为明显,其三效起燃温度可降低50℃以上,在氧化还原数S=1．0和S=1．5两种条件下进行对比,表明碱金属的掺入可以拓宽催化剂的操作窗口,低电负性碱金属的掺入,一方面增强了电负性物种CO,NO和O2的吸附能力,同时减弱了电正性物种C3H6的吸附能力,另一方面,削弱了吸附态分子NO中N-O键的键能,促进其解离,抑制了N2O的生成。     

The impact of the type and position of the halogen atom on the biodegradation of halosubstituted benzyl alcohols

The biodegradation of 2‐halosubstituted and 4‐halosubstituted benzyl alcohols was studied using two sources of biodegrative micro‐organisms: mixed culture from the ?TUDA waste water treatment plant, Dom?ale, and the white rot fungus Phanerochaete chrysosporium strain MZKI B‐223 (ATCC 24725). The results obtained by this study indicate the interrelationship between the types of micro‐organism used in the experiments and the type and position of the halogen element on the aromatic ring.