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1.
利用磁性二氧化硅表面接枝的聚丙烯酰胺络合Cu2+离子,制备了表面铜螯合磁性SiO:材料,采用傅立叶红外光谱(FT.IR),X射线衍射(XRD)对该磁性材料进行了表征,并通过配位作用固定化漆酶,考察了其对水中2,4-二氯酚(2,4-DCP)的催化降解效能及主要影响因素。结果表明,表面铜螯合磁性SiO:固定化漆酶对2,4-DCP具有较好的催化降解效能,利用8g/L固定化漆酶催化降解50mL初始浓度为24.25mg/L的2,4-DCP,反应12h2,4-DCP去除率达91%;当pH值在3.0~6.0范围内时,2,4-DCP的去除率随反应pH值的增加而升高;2,4-DCP初始浓度在14.39~257.6mg/L范围内时,反应12h,2,4-DCP的去除率均达85%以上;给酶量增加促进2,4-DCP的去除,但过多的给酶量导致单位质量固定化漆酶催化降解2,4-DCP的速率下降;水中硫酸根离子对固定化漆酶催化降解2,4-DCP具有明显的促进作用,而碳酸氢根离子明显抑制反应的进行。  相似文献   

2.
包埋固定化微生物法处理含油废水研究   总被引:18,自引:0,他引:18  
本研究通过包埋固定化微生物法固定除油菌(Y1’菌),用于处理含油废水,并以水体中乳化油去除率为指标考察了影响乳化油降解的各种因素。选用聚乙烯醇(PVA)-海藻酸钠(SA)复配作为包埋固定化载体材料,制备成固定化微生物小球(IMB),通过实验优化了IMB制备的工艺条件。连续批次除油实验结果表明,在25-40℃,固液比1:10,HRT为6h的条件下,进水油含量在20—50mg/L,乳化油去除率可达85%-90%,出水油含量低于5mg/L。  相似文献   

3.
为寻求一种廉价高效的漆酶固定化方法,以树脂D380为载体、戊二醛为交联剂,结合吸附法和交联法固定真菌漆酶,并研究固定化漆酶的性质。最优固定化条件:1g载体在20mL0.7%的戊二醛溶液中交联2h后,加入2mL稀释酶液和5mLpH为4的醋酸一醋酸钠缓冲溶液,在25℃下吸附反应6h,最终获得的酶活回收率为65.94%。固定化漆酶的最适温度为20℃,最适pH为4,在4℃下保存14d仍保持约80%的酶活力。自由漆酶和固定化漆酶的Km值分别为1.207mmol/L和1.616mmol/L,说明固定后漆酶对底物的亲和力有所下降。  相似文献   

4.
Phlebia acanthocystis TMIC34875是一株具有七氯降解能力的木材腐朽菌。为利用微生物技术去除环境中的七氯残留提供理论依据,研究了该菌株及其粗酶液对七氯的降解性能及其动力学特性。结果表明,菌株在七氯的初始浓度为50μmol/L时具有最大降解速率,为0.3031μmol/(L·h);而菌体接种量为15%时,降解速率达到最高,为0.2045μmol/(L·h)。降解酶定位研究表明,七氯的降解主要是胞内酶在起作用。七氯胞内酶降解的酶促反应最适温度是35℃,在30-40℃之间有较高的催化活性;最适pH值为5.0,在pH 4.5-6.0之间有较高的催化活性,最适条件下反应1 h后七氯的降解率为65%。胞内粗酶液降解七氯的米氏常数K m为5.42μmol/L,最大反应速率V max为4.55μmol/min。胞内酶处理体系的GC/MS图谱显示,主要降解产物为1-羟基六氯、1-羟基-2,3-环氧六氯和环氧七氯,表明胞内酶对七氯的初始代谢机理同菌株相似,均是通过环氧化和置换反应来完成的。  相似文献   

5.
以原位沉淀法制备的氧化石墨烯/Fe3O4磁性纳米复合颗粒为固定化载体,1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐为交联剂,成功固载了辣根过氧化物酶。探讨了固定化条件对辣根过氧化酶活性的影响以及固定化酶的理化性质,实验结果表明,固定化最佳pH为6、温度为30℃、时间为11 h、交联剂浓度为1 mg/L。与游离酶相比,固定化酶具有良好的pH稳定性和热稳定性。最后将固定化酶用于降解水中的苯酚和2,4-二氯酚,并考察了固定化酶的重复利用性。  相似文献   

6.
考察了海藻酸钠(SA)和聚乙烯醇(PVA)含量对固定化载体性能的影响,并筛选了最优条件制备固定化氨氮降解菌,研究其对氨氮废水的处理效果。当PVA和SA质量分数分别为8.00%、1.00%时,制成的固定化载体抗压性能最好,能够形成丰富的多孔结构。固定化氨氮降解菌在处理氨氮废水前驯化168h,可以恢复较高活性。在固定化氨氮降解菌投加量2%(质量分数)、反应温度30℃、pH 8.01、溶解氧3.0 mg/L的条件下反应60h,氨氮废水中的氨氮质量浓度从最初的3 835.29 mg/L降为82.35mg/L,去除率为97.85%。固定化氨氮降解菌在投加量低于氨氮降解菌的情况下,仍然能实现与之相近的氨氮废水处理效果,证明固定化氨氮降解菌能高效处理高浓度氨氮废水。  相似文献   

7.
通过批实验和柱实验研究了三氯乙烯(TCE)初始浓度、四氯乙烯(PCE)等对零价铁去除三氯乙烯的影响,并建立了三氯乙烯降解的反应动力学方程。结果表明:(1)零价铁对TCE具有较好的降解效果,反应符合准一级反应动力学方程,表观反应速率常数随TCE浓度的增加而减小;(2)在铁粉充足的条件下,TCE初始浓度对降解效果影响不显著,且TCE去除率皆可达到90%以上;(3)PCE的存在抑制了TCE的脱氯反应。PCE和TCE共存时,TCE的最大去除率仅为64.2%;TCE脱氯反应的表观反应速率明显降低,反应半衰期由TCE单独存在时的6.8~9.7 h增大到66 h~346.5 h。  相似文献   

8.
灵芝漆酶对直接蓝86的催化脱色性能   总被引:1,自引:0,他引:1  
利用灵芝菌Ganoderma lucidum U-281漆酶对直接蓝86进行酶促氧化脱色,并对其降解机理进行了探讨。结果表明,染料-漆酶共反应体系在20~50℃及pH小于5.0范围内,直接蓝86均可脱色50%以上;漆酶对直接蓝86具有宽泛的浓度适应性,对300 mg/L的该染料仍具有耐受性。最优脱色工艺参数为温度40℃、pH 5.0、染料初始浓度200 mg/L、漆酶用量1 U/mL。在优化条件下,直接蓝863 h的脱色率达到54.54%,48 h脱色率达到91.54%。紫外-可见吸收光谱分析表明,漆酶的酶促氧化导致染料的分子结构产生了变化,是造成直接蓝86脱色的主要发生机制。  相似文献   

9.
采用核桃壳质生物炭为固定化材料,以铜矿污泥和焦化废水污泥微生物为混合菌源,通过正交试验确定了优化的固定化条件:0.1 g 16目生物炭,微生物接种量5 mL(600 nm下的吸光度(OD600)=1.0),固定时间36 h,此时固定化菌系可在48 h降解76.13%的菲。温度20~40℃、pH 4.00~9.00范围内,固定化菌系的降解能力优于游离态菌系。在温度为30℃、pH为7.00时,培养7 d后,固定化菌系对菲的降解率高达95.94%。固定化菌系在低温、低pH下均表现出更强的适应性,对菲的降解率比游离态菌系更高。此外,固定化体系中生物炭水溶提取物可充当共代谢碳源,促进菌系的生长。  相似文献   

10.
包埋固定化微生物法处理含油废水研究   总被引:1,自引:0,他引:1  
本研究通过包埋固定化微生物法固定除油(Y1#菌),用于处理含油废水,并以水体中乳化油去除率为指标考察了影响乳化油降解的各种因素.选用聚乙烯醇(PVA)-海藻酸钠(SA)复配作为包埋固定化载体材料,制备成固定化微生物小球(IMB),通过实验优化了IMB制备的工艺条件.连续批次除油实验结果表明,在25~40℃,固液比1∶10,HRT为6 h的条件下,进水油含量在20~50 mg/L,乳化油去除率可达85%~90%,出水油含量低于5 mg/L.  相似文献   

11.
介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠  相似文献   

12.
Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.  相似文献   

13.
不同泥源对厌氧氨氧化反应器启动的影响   总被引:2,自引:1,他引:1  
李祥  黄勇  袁怡  张丽  朱莉 《环境工程学报》2012,6(7):2143-2148
采用2套上流式生物膜反应器,分别接种少量厌氧氨氧化污泥和大量硝化污泥,考察其对厌氧氨氧化反应器启动的影响。污泥接种入反应器后,测得接种厌氧氨氧化污泥的反应器(R1)内MLSS为0.22 g/L,另一个反应器(R2)MLSS为2.7 g/L。与直接接种厌氧氨氧化污泥相比,R1经过72 d的运行才显现出厌氧氨氧化特性。经过114 d的培养,前者氮去除速率由0.23 kg/(m3.d)提升到5.29 kg/(m3.d),总氮去除率大于89%;R2的氮去除速率由0.01 kg/(m3.d)提升到1.1 kg/(m3.d),总氮去除率大于84.6%。说明普通污泥启动需要一个较长的筛选过程,直接接种少量的厌氧氨氧化污泥比接种普通的污泥能够更快启动厌氧氨氧化反应器。  相似文献   

14.
Evaluation of the presence of drugs of abuse in tap waters   总被引:1,自引:0,他引:1  
A total of seventy samples of drinking water were tested for non-controlled and illicit drugs. Of these, 43 were from Spanish cities, 15 from seven other European countries, three from Japan and nine from seven different Latin American countries. The most frequently detected compounds were caffeine, nicotine, cotinine, cocaine and its metabolite benzoylecgonine, methadone and its metabolite EDDP. The mean concentrations of non-controlled drugs were: for caffeine 50 and 19 ng L−1, in Spanish and worldwide drinking water respectively and for nicotine 13 and 19 ng L−1. Illicit drugs were sparsely present and usually at ultratrace level (<1 ng L−1). For example, cocaine has mean values of 0.4 (Spain) and 0.3 ng L−1 (worldwide), whereas for benzoylecgonine, these mean values were 0.4 and 1.8 ng L−1, respectively. Higher concentrations of benzoylecgonine were found in Latin American samples (up to 15 ng L−1). No opiates were identified in any sample but the presence of methadone and EDDP was frequently detected. Total mean values for EDDP were 0.4 ng L−1 (Spain) and 0.3 ng L−1 (worldwide). Very few samples tested positive for amphetamines, in line with the reactivity of chlorine with these compounds. No cannabinoids, LSD, ketamine, fentanyl and PCP were detected.  相似文献   

15.
Biodegradation mechanisms were elucidated for three dibenzoate plasticizers: diethylene glycol dibenzoate (D(EG)DB), dipropylene glycol dibenzoate (D(PG)DB), both of which are commercially available, and 1,6-hexanediol dibenzoate, a potential green plasticizer. Degradation studies were done using Rhodococcus rhodochrous in the presence of pure alkanes as a co-substrate. As expected, the first degradation step for all of these systems was the hydrolysis of one ester bond with the release of benzoic acid and a monoester. Subsequent biodegradation of the monobenzoates of diethylene glycol (D(EG)MB) and dipropylene glycol (D(PG)MB) was very slow, leading to significant accumulation of these monoesters. In contrast, 1,6-hexanediol monobenzoate was quickly degraded and characterization of the metabolites indicated that the biodegradation proceeded by way of the oxidation of the alcohol group to generate 6-(benzoyloxy) hexanoic acid followed by β-oxidation steps. This pathway was blocked for D(EG)MB and D(PG)MB by the presence of an ether function.The use of a pure hydrocarbon as a co-substrate resulted in the formation of another class of metabolites; namely the esters of the alcohols formed by the oxidation of the alkanes and the benzoic acid released by hydrolysis of the original diesters. These metabolites were biodegraded without the accumulation of any intermediates.  相似文献   

16.
影响混凝效果的因素众多,混凝沉淀烧杯试验是进行水的混合、絮凝、沉淀工艺研究、设计和生产指导的最有效方法之一,阐述了智能型混凝试验搅拌器的设计原理和技术性能.  相似文献   

17.
生物质快速热裂解主要参数对生物油产率的影响   总被引:5,自引:0,他引:5  
以松木木屑为原料,在自制的小型流化床上,开展了生物质热裂解温度、生物质粒径和进料速率对生物油产率的影响实验研究.结果表明,在热裂解温度分别为450、475、500、525和550℃条件下,当热裂解温度为500℃时,生物油产率最高,平均产率达到53.33%(质量百分比).反应温度越高,炭产量越低,不可冷凝气体产量越高,气体发热值越高;粒径<1 mm的生物质其粒径对生物油产率影响不大;生物质进料速率增加时,生物油产率增加.本研究为生物能的利用提供了新的途径.  相似文献   

18.
The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.  相似文献   

19.
寻找廉价而高效的替代原料是实现生物柴油产业化的关键所在.微藻以含油量高、生长周期短、环境适应能力强、生物产量高等优点,有望成为一种极具潜力的生物柴油生产原料.然而,目前尚存在微藻培养低效成本高和微藻回收效率低两大难题.综述了微藻培养与回收过程中的关键技术,并对存在的两大难题及其改进技术进行了详细的探讨.最后,总结并展望了微藻培养、回收技术未来的发展趋势.  相似文献   

20.
造纸废水混凝处理中SFT助凝替代性研究   总被引:1,自引:0,他引:1  
中小造纸厂废水处理常用PAC作混凝剂 ,PAM作助凝剂。由于PAM成本很高 ,影响了处理设备的投运率。用超细滑石粉 (SFT)替代PAM助凝 ,与混凝剂PAC配合 ,其混凝处理效果基本相当 ,但是处理成本降低 0 .10元 /m3 。由于SFT属环境无害材料 ,不会给排泥带来二次污染  相似文献   

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