“水解-A_P/O-化学沉淀-过滤”工艺处理涂装污水

涂装污水成分复杂,有机物、磷酸盐和锌含量高,可生化性较差。工程实践采用"水解-ApO-化学沉淀-过滤"工艺处理涂装污水,BOD_5、COD、磷酸盐和总锌的去除率分别为98.7%、98.5%、97.5%和98.8%,出水水质优于(GB 8978—1996)《污水综合排放标准》一级,并可满足回用要求。处理能力为1 500 m~3/d的处理设施的投资费用为350万元,运行费用为0.86元/m~3。实践证明,该工艺处理效果好,投资成本和运行费用低,耐冲击负荷能力强,切实可行。     

Synergistic effect of N- and F-codoping on the structure and photocatalytic performance of TiO2

Three types of TiO₂ nanostructures were synthesized via a facile hydrolysis method at 195 °C. Effects of the preparation method and doping with N and F on the crystal structure and photocatalytic performance of TiO₂ were investigated. The nanomaterials were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller porosimetry, ultraviolet–visible diffuse reflectance spectroscopy and fluorescent emission spectra. Their photo-catalytic activity was examined by the photodegradation of methylene blue in aqueous solution under both ultra-violet and visible light irradiation. The results show that nitrogen and fluorine co-doped anatase TiO₂ had the characteristics of a smaller crystalline size, broader light absorption spectrum and lower charge recombination than pure TiO₂. Most importantly, more efficient photocatalytic activity under both ultra-violet and visible light was observed. The obtained N–F-TiO₂ nanomaterial shows considerable potential for water treatment under sunlight irradiation.     

区域工业污染物增长份额偏离分析

以吉林省为例,在汇总各类污染物排污费的基础上,应用份额偏离分析方法解析地区污染增长,从空间关联和结构关联等方面探索区域污染治理改进方向.结果表明,①全域尺度上结构偏离分量和竞争力偏离分量的变异系数分别为15.78和34.05,清洁生产和污染治理等技术措施对于降低区域污染的作用远远大于产业组织方式的影响;②邻域尺度上地区增长份额多数高于全域尺度模型计算结果,进一步对比结构偏离分量和竞争力偏离分量的组合关系,有助于通过空间组织方式改进污染治理,而降低长春市和吉林市的污染排放对于改善吉林省区域环境具有重要意义;③从污染物结构关联方面将地区污染分为复合污染型和单项污染型,有利于通过产业组织方式推动区域产业生态化发展;④按照各市州所属组别的相似性,并考虑地理临近,吉林省产业生态化空间组织结构可以划分为中部组、东南组、西部组和东部组.     

利用酸法和酶法水解玉米芯发酵生产木糖醇

利用稀硫酸和纤维素酶预处理玉米芯,得到不同木糖含量的水解液,并利用热带假丝酵母进行发酵.结果表明,酸法获得水解液中的木糖浓度较高,酸法水解组中木糖醇产量和转化率均略高于酶法水解组,两者间差异不显著.     

应用钙法除磷-碱解-微电解组合工艺预处理吡虫啉农药废水

根据吡虫啉农药废水成分复杂，含有大量有毒有害物质的特点，在小试实验研究的基础上，确定了预处理的组合工艺流程为：钙法除磷-碱解-催化微电解。实验结果表明，预处理的适宜参数为：钙法除磷的pH值11，搅拌速度为100 r/min，钙的投加量为理论计算值的1.4倍；碱解反应的温度70℃，pH值11，反应时间2 h；催化微电解反应的pH值3～4，曝气时间3 h，催化剂与铸铁屑的质量比1∶5。组合工艺对COD、色度、磷的总去除率分别达到81%、90%和99.99%，废水的可生化性能得到很大改善。组合工艺不仅适用于预处理高浓度吡虫啉农药废水，也能为其他高浓度、难生物降解农药废水的治理提供有益的参考。     

Transient‐phase and steady‐state kinetics of lipase‐catalyzed ester hydrolysis 1

Abstract

An experimental study has been made of both the steady‐state and the transient‐phase (presteady‐state) kinetics of the hydrolyses of several saturated aliphatic esters of p‐nitrophenol catalyzed by wheat germ lipase. The analysis of the presteady‐state part revealed two transients indicating that lipase‐catalyzed reactions proceed via a two‐intermediate mechanism suggested for other esterases. The possibility of more than one species of the enzyme engaged in catalytic activity is discussed and a reaction mechanism scheme is proposed accordingly.     

Enzyme-Mediated Reactions of Oligosaccharides and Polysaccharides

Two types of enzymatic reactions are given here as examples of synthetic problems encountered in industry. In the first case, commercially available -D-galactosidase from Escherichia coli was used as a catalyst to transfer galactose from -lactose to oligosaccharides. A preference for galactosyl transfer to the 3- or 4-position of the sugar moiety of the oligosaccharide was observed for the products. As expected, only the -anomer was produced. A wide variety of sugars, including disaccharides, trisaccharides, cellotetraose, and maltodextrins, has been shown to act as acceptors, yielding oligosaccharides. In the second example, -galactomannan that had been previously treated to contain cationic groups (cationic guar gum) was subjected to treatment with a series of inexpensive commercial enzymes such as lipases, protease, and cellulases. Some enzyme preparations showed significant changes in the viscosities of 1% cationic guar solution. For example, lipases from Aspergillus niger and Aspergillus saitoi and protease XIII from Rhizopus niveus produced a substantial viscosity reduction (0–20% of original viscosity). These examples demonstrate the utility of low-cost enzymes in manipulating polymer structures.     

挺水植物生物炭对硫丹的吸附及催化水解作用

以美人蕉、菖蒲、芦苇、茭白、再力花、芦竹等挺水植物为原料,在限氧升温（550℃）条件下制备6种不同性质的生物炭,研究其组成及结构对硫丹吸附和催化水解作用.结果表明：550℃下热解,湿地植物生物炭所含灰分高于一般农产品废弃物,介于10.88%~31.11%间.生物炭表面芳香类官能团较多,孔隙部分呈碎片化,以介孔为主.6种生物炭对硫丹都具良好吸附性能.吸附行为主要发生在含致密有机质的生物炭表面,包括疏水、扩散及分配作用等.中/碱性条件下,美人蕉生物炭、菖蒲生物炭及再力花生物炭能有效去除水溶液中的硫丹,去除率为96.77%~98.57%.中性条件下,因生物炭对硫丹的催化,对硫丹的去除率提高约16.57%~72.57%.     

污水中基于酶活性分析的硫酸雌酮雌激素效应

在污水处理厂尾水中,雌酮（E1）和硫酸雌酮（E1-3-S）分别是赋存浓度最高的自由态雌激素和结合态雌激素.E1-3-S难以被生物降解且雌激素效应有限,但环境条件适宜时可在芳基硫酸酯酶（AryS）作用下通过水解释放出具有雌激素效应的E1.本论文提出了一种利用AryS活性值和E1-3-S酶促水解动力学参数计算E1-3-S半寿期的方法.根据现场取样分析得到了重庆市某污水处理厂生物处理构筑物内混合液,合流制管道溢流口与尾水受纳水体底泥中在冬、春、夏3个季节的AryS活性值,其均值分别为417.41~941.14,91.55~179.42,28.11~59.64μg对硝基酚/（g·h）.在20℃的实验室条件下,E1-3-S的酶促水解遵循一级动力学模式（P<0.01）,且水解速率K_d与AryS活性呈线性正相关（R²=0.9774）.根据春季的AryS活性数据和实验室条件下E1-3-S水解速率与酶活性的线性回归方程推算,得到了在污水处理厂生物构筑物内、合流制管网溢流口和污水厂尾水排放点附近水体中E1-3-S在对应环境温度条件下通过酶促水解的半寿期分别为33.5,153.0,410.0h.该方法可用于评估硫酸型结合态雌激素在水环境中的雌激素效应释放风险.     

高原喀斯特土壤有机碳短期稳定的温度作用机制

探明有机碳稳定的温度作用机制,是评估全球变化背景下土壤碳源/汇演变趋势的关键.应用土壤密度分组和酸水解技术,采用红外线辐射增温法,对比研究不同升温情景下高原喀斯特土壤及其物理和生化组分中有机碳密度的短期(4a)变化特征.升温情景包括不升温(对照)、对称升温(全年同步升温2.0℃)和非对称升温(冬春/夏秋季升温幅度为2.5℃/1.5℃、3.0℃/1.0℃、3.5℃/0.5℃和4.0℃/0℃,低度、中度、高度和极端非对称升温),其中中度非对称升温与该区域多年升温情景类似.结果表明,不同升温情景下表层(0~15 cm)土壤有机碳密度在1.95~2.02 kg·m-2之间,其差异不显著,且与对照(1.94 kg·m-2)差异不显著.升温处理间土壤轻组和重组碳密度、重组顽固性碳密度差异不显著,且与对照差异不显著.5个升温处理轻组顽固性碳平均密度是对照的1.18倍,其中对称升温、低度和中度非对称升温处理显著高于对照.轻组顽固性碳密度和轻组顽固性碳指数随升温的非对称性增加而降低,其中对称升温处理均显著高于中度、高度和极端非对称升温.亚表层(15~30 cm)土壤及其物理和生化组分中有机碳密度对短期升温均不敏感.研究揭示:短期内,升温提高了高原喀斯特土壤非保护组分中有机碳顽固性.基于对称升温情景并不一定会误估全球变暖对土壤有机碳数量和土壤碳物理保护能力的影响,但可能会高估表层土壤(0~15 cm)非保护组分有机碳顽固性.