新型材料淀粉微球对Cu2＋、Cr3＋和Pb2＋的吸附机理研究

以可溶性淀粉为原料,在反相悬浮体系中合成N,N′-亚甲基双丙烯酰胺交联淀粉微球为载体,研究了新型吸附材料淀粉微球（cross-linked starch microsphere,CSMs）对Mn＋（Cu2＋、Cr3＋、Pb2＋）的静态吸附行为。利用扫描电镜、X射线衍射仪和红外光谱仪对微球及其吸附产物进行表征,分析讨论了3种金属原子结构,研究了吸附机理。结果表明：308K时,Cu2＋、Pb2＋和Cr3＋的饱和吸附量分别是2.43、0.30和0.27 mmol/g,CSMs对Cu2＋离子吸附能力最强,并且其通过物理吸附、配位吸附方式吸附Mn＋,并得出引起微球吸附能力大小可能与金属离子电荷、离子半径和外层电子排布的差异因素有关。     

膜基活化溶液中活化剂在回收温室气体CO2过程中的作用

将AMP和PZ作为活化剂添加于MDEA溶液中,形成活化溶液,研究了膜基活化溶液回收温室气体CO2性能,着重考察活化剂的活化作用和对膜接触器传质加强的影响,提出一个活化机理来解释活化现象,建立了阻力层方程模型, 并模拟膜基活化溶液回收CO2的传质过程。结果表明,活化剂对膜接触器传质的加强起到重要作用,具有双氨基环状结构的PZ对传质的加强作用高于具有空间位阻结构的AMP;活化溶液的CO2回收率和传质通量明显高于未活化的MDEA溶液,活化性能PZ＞AMP;活化剂的活化效应与分子结构有关;流体力学的改变对传质的影响有限,活化剂的反应动力学对传质的加强起主导作用;阻力层方程模型能较好地模拟膜基活化溶液回收CO2传质过程,传质通量和总传质系数的模型值与实验值符合较好。     

Photocatalytic oxidation of monuron in the suspension of WO3 under the irradiation of UV-visible light

A comprehensive study of the degradation of monuron, one of the phenylurea herbicides, was conducted by UV-Vis/WO₃ process. It was found that hydroxyl radicals played a major role in the decay of monuron while other radicals (e.g. superoxide) and hole might also contribute to the decomposition of monuron. The oxidation path likely plays a major role in the generation of hydroxyl radicals. The effects of initial pH level, initial concentration of monuron, and inorganic oxidants on the performance of UV-Vis/WO₃ process were also investigated and optimized. Comparison between monuron decay pathways by UV-Vis/WO₃ and UV/TiO₂ was conducted. The decay mechanisms, including N-terminus demethylation, dechlorination and direct hydroxylation on benzene ring, were observed to be involved in the oxidation of monuron in these two processes. Sixteen intermediates were identified during the photodegradation of monuron and degradation pathways were proposed accordingly.     

Catalytic destruction of pentachlorobenzene in simulated flue gas by a V2O5-WO3/TiO2 catalyst

Pentachlorobenzene (PeCB) in simulated flue gas was destructed by a commercial V₂O₅-WO₃/TiO₂ catalyst in this study. The effects of reaction temperature, oxygen concentration, space velocity and some co-existing pollutants on PeCB conversion were investigated. Furthermore, a possible mechanism for the oxidation of PeCB over the vanadium oxide on the catalysts was proposed. Results show that the increase of gas hourly space velocity (GHSV) and the decrease of operating temperature both resulted in the decrease of PeCB removal over the catalyst, while the effect of the oxygen content in the range of 5-20% (v/v) on PeCB conversion was negligible. PeCB decomposition could be obviously affected by the denitration reactions under the conditions because of the positive effect of NO but negative effect of NH₃. The introduction of SO₂ caused the catalyst poisoning, probably due to the sulfur-containing species formed and deposited on the catalyst surface. The PeCB molecules were first adsorbed on the catalyst surface, and then oxidized into the non-aromatic acyclic intermediates, low chlorinated aromatics and maleic anhydride.     

The OH-induced degradation mechanism of 4-chloro-2-methylphenoxyacetic acid (MCPA) with two forms in the water: a DFT comparison

The initial degradation mechanisms of OH and 4-chloro-2-methylphenoxyacetic acid (MCPA) including molecular form and anionic form are studied at the MPWB1K/6-311+G(3df, 2p)//MPWB1K/6-31+G(d, p) level. Possible reaction pathways of H-atom abstraction and OH addition are considered in detail. By result comparison analysis, it is found that the reaction mechanisms for OH and two forms of MCPA are different, and most reactions for anionic MCPA are easier than those for molecular MCPA. For H-atom abstraction reactions, the calculated energies show that OH abstracting H-atom from -CH₃ group of molecular MCPA is the most kinetically favorable process; the potential energy surface for anionic MCPA indicates that H-atom in -CH₂ group is slightly easier to be abstracted than that in -CH₃ group. For OH addition reactions, the addition of OH to the C1 site is the initial step for molecular MCPA and the predominant product is 4-chloro-2-methylphenol (denoted P3), while the C4 site is the most reactive site for anionic MCPA and the primary product results from the hydroxylation of the aromatic ring, which is in good agreement with the experimental observation. In additional, results from PCM calculations show that most reactions in water phase are more kinetically favorable than those in gas phase, though the mechanisms discussed above will not be changed.     

建筑施工企业安全质量标准化常见问题及对策

本文介绍了建筑施工企业开展安全质量标准化达标活动的背景,并从"对安全质量标准化达标活动重视程度不够、主动性不强"、"全员参与程度低"等几个方面指出了建筑施工企业开展安全质量标准化达标活动中存在的问题;同时提出了"统一思想,提高对安全质量标准化达标的认识"、"强化安全生产主体责任的落实"等8条解决措施,并提出了"建立有效...     

氚在黏土矿物等多孔介质中的滞留机制

通过电感耦合等离子体光谱(ICP)、热重(TG)等分析方法对黏土矿物的结构成分、加热特性等进行了检测;通过蒸馏冷凝等实验,实现了对吸附后黏土矿物的吸附水、层间水、结构水的分离,检测了氚在黏土矿物结构内外各类型水中的分布;通过红外吸收光谱(IR)等分析方法对氚在黏土矿物结构中的吸附位置及形态进行了检测研究;通过同位素效应...     

催化臭氧氧化过程中溴酸盐的生成机制研究

以黄河下游某水厂滤后水为目标物,选择了9种催化剂,在间歇反应装置中研究了单独臭氧和催化臭氧氧化过程中溴酸盐（BrO 3-）的生成情况,结果表明,在催化臭氧氧化过程中,NiO、CuO、Fe3O4、Al2O3加入使BrO 3-质量分数分别降低34.0%、32.8%、29.2%、20.8%.选取Fe3 O4作为催化剂研究催化...     

多环芳烃在冬小麦体内的吸收与转运及富集研究进展

多年来以煤炭为主的能源消费结构和经济社会持续发展,导致我国PAHs(多环芳烃)排放量居高不下,直接造成土壤和大气PAHs严重污染.为了探明PAHs在冬小麦体内的积累过程和调控机制,在系统分析PAHs在冬小麦体内的吸收、转运和富集的基础上,重点阐述了冬小麦PAHs根系吸收和叶面吸收影响因素方面的最新研究进展.研究发现:① 小麦根系对PAHs的吸收包括主动吸收和被动吸收两种方式,其中主动吸收是一个载体协助、消耗能量、PAHs与H+共运的过程;被动吸收除了在高等植物中普遍存在的简单扩散外,水-甘油通道也参与了该过程. ② PAHs通过气态、颗粒态沉降到小麦叶面角质层或直接通过气孔进入叶片. ③ 影响PAHs根系和叶面吸收的主要因素包括PAHs理化性质、植物生理状况、环境因素等. ④ 小麦根系吸收的PAHs可以向地上部转运,并且与辛醇-水分配系数(K_OW)、蒸腾速率、土壤中氮的形态和浓度有关.主要问题:① 对于小麦叶片吸收的PAHs向基运输机理有待进一步研究. ② 农田生态系统中冬小麦往往遭受土壤及大气双重污染,根系吸收及叶面吸收分别对其体内积累PAHs的贡献尚不清楚.因此,需关注韧皮部、木质部在PAHs转运中所起的作用;利用同位素示踪、双光子激发显微镜等先进技术观察和跟踪PAHs如何进入小麦以及在小麦叶中的转移和分布,阐明PAHs叶面吸收的微观机理;注重大田试验研究,为揭示冬小麦对PAHs的吸收、积累及调控机理,同时也为有机污染地区生产安全农产品提供重要依据.      

1株耐油甲醛降解菌的分离鉴定及降解特性

烹饪油烟的健康危害一直以来受到广泛关注.以甲醛为代表的醛类污染物是烹饪油烟排放的主要污染物之一.微生物法降解甲醛具有工艺简单、成本低及无污染等优点.本研究从烹饪油烟冷凝液中分离筛选出1株具有甲醛降解能力的菌株XF-1,经序列鉴定结合菌落形态特征及生理生化试验,该菌株被鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens sp.).该菌株具有能耐受高油环境的性能,最大耐受浓度为900 g·L^-1.在甲醛浓度为100 mg·L^-1的培养基中,菌株XF-1在34 h内的甲醛降解率为95.80%;当甲醛初始浓度<300 mg·L^-1时,菌株XF-1能够在120 h以内完全降解溶液中的甲醛;甲醛浓度为800mg·L^-1时,在96 h,菌株XF-1的降解率达到73.01%,并可耐受1.5 g·L^-1浓度的甲醛.通过单因素(p H、接种量、甲醛浓度和温度)试验,得到该菌株最佳生长温度为30℃、最佳生长pH为6左右,最佳接种量为10%.利用GC-TOF-MS进一步分...