基因工程菌强化芳香化合物的处理工艺

分别固定克隆有甲苯加双氧酶基因的工程菌和筛选出的野生菌株,串联两种固定化细胞反应器,研究以基因工程菌突破关键步骤的限制,筛选菌株辅助完成彻底降解芳香类污染物复合工艺可行性和强化效果.克隆有苯降解过程中的关键基因——甲苯加双氧酶的基因工程菌E. coli. JM109(pKST11)对苯具有较高的降解效率和降解速度,应用于固定化细胞反应器中效果突出.在较短的水力停留时间内,可以将1500mg/L苯降解70%,降解速度为1.11mg/(Ls),延长水力停留时间,可以使去除率达到95%以上.该反应器对高浓度的苯具有突出的处理效果.同时所得到的产物为环己二烯双醇,可以被野生非高效菌W3快速利用.     

镉抗性菌株的筛选及对番茄吸收镉的影响

通过在培养基中加入一定浓度的镉(CdSO₄8H₂O, Cd 200mg/L),从土壤中分离到3株具有很强的镉抗性细菌,经初步鉴定,它们分别属于假单胞菌属和芽胞杆菌属(编号分别为NJ3、NJ9、RJ16).将分离到的3株菌分别接种到添加镉(200mg/kg)的土壤并进行番茄盆栽试验,结果表明,供试抗性菌株均能显著促进植株生长,活化植株根际镉,接RJ16菌株处理的番茄地上部植株干重、根际有效镉含量及植株吸收的镉含量分别比不接菌对照增加64.2%,46.3%,107.8%,而接NJ3和NJ9菌株处理的番茄植株吸收的镉与对照植株吸收的镉没有显著差异.     

G-CNTs/PVDF mixed matrix membranes with improved antifouling properties and filtration performance

A novel nanocomposite OMWCNT-A-GO was synthesized by conjugating OMWCNT and GO. The P-OMWCNT-A-GO membrane was fabricated by non-solvent induced phase inversion. The P-OMWCNT-A-GO exhibits the best water flux, BSA rejection and flux recovery. It should be due to the enhanced membrane pore size, porosity and hydrophilicity. Although carbon nanomaterials have been widely used as effective nanofillers for fabrication of mixed matrix membranes (MMMs) with outstanding performances, the reproducibility of the fabricated MMMs is still hindered by the non-homogenous dispersion of these carbon nanofillers in membrane substrate. Herein, we report an effective way to improve the compatibility of carbon-based nanomaterials with membrane matrixes. By chemically conjugating the oxidized CNTs (o-CNTs) and GO using hexanediamine as cross-linker, a novel carbon nanohybrid material (G-CNTs) was synthesized, which inherited both the advanced properties of multi-walled carbon nanotubes (CNTs) and graphene oxide (GO). The G-CNTs incorporated polyvinylidene fluoride (PVDF) MMMs (G-CNTs/PVDF) were fabricated via a non-solvent induced phase separation (NIPS) method. The filtration and antifouling performances of G-CNTs/PVDF were evaluated using distillate water and a 1 g/L bovine serum albumin (BSA) aqueous solution under 0.10 MPa. Compared to the MMMs prepared with o-CNTs, GO, the physical mixture of o-CNTs and GO and pure PVDF membrane, the G-CNTs/PVDF membrane exhibited the highest water flux up to 220 L/m²/h and a flux recovery ratio as high as 90%, as well as the best BSA rejection rate. The excellent performances should be attributed to the increased membrane pore size, porosity and hydrophilicity of the resulted membrane. The successful synthesis of the novel nanohybrid G-CNTs provides a new type of nanofillers for MMMs fabrication.     

Cultivation of aerobic granular sludge in a conventional,continuous flow,completely mixed activated sludge system

Aerobic granules were formed in a conventional, continuous flow, completely mixed activated sludge system (CMAS). The reactor was inoculated with seed sludge containing few filaments and fed with synthetic municipal wastewater. The settling time of the sludge and the average dissolved oxygen (DO) of the reactor were 2 h and 4.2 mg·L^-1, respectively. The reactor was agitated by a stirrer, with a speed of 250 r·min^-1, to ensure good mixing．The granular sludge had good settleability, and the sludge volume index (SVI) was between 50 and 90 mL·g^-1. The laser particle analyzer showed the diameter of the granules to be between 0.18 and 1.25 mm. A scanning electron microscope (SEM) investigation revealed the predominance of sphere-like and rod-like bacteria, and only few filaments grew in the granules. The microbial community structure of the granules was also analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Sequencing analysis indicated the dominant species were α, β, and γ-Proteobacteria, Bacteroidetes, and Firmicutes. The data from the study suggested that aerobic granules could form, if provided with sufficient number of filaments and high shear force. It was also observed that a high height-to-diameter ratio of the reactor and short settling time were not essential for the formation of aerobic granular sludge.     

辛基酚聚氧乙烯醚混合菌的构建及响应面优化

为提高辛基酚聚氧乙烯醚（OPnEO）的生物降解效果,在本实验室已筛选出的H1、TXBc10、OPQb11、TXBa23四株OPnEO高效降解菌的基础上,首次从构建OPnEO混合菌的角度,着重探究了四菌株等比例不同组合降解OPnEO的效果.结果表明,混合菌L9（H1：TXBc10：TXBa23为1：1：1）培养7d后对初始浓度500mg/LOPnEO的降解率最高,达到56.44%,比各单一菌株降解效果有较明显提高.运用单因素试验考察了影响L9的相关因素,初步确定L9降解OPnEO的最适外加碳源和氮源分别为葡萄糖和胰蛋白胨,最适初始pH值为7.0,最适温度为28℃,最适接种量为4%.Plackett-Burman试验筛选获得影响OPnEO降解率的3个显著因子为L9接种量、温度及初始pH值.最陡爬坡试验逼近3个显著因子的最大响应区域,采用Box-Behnken试验设计及响应面法分析,确定L9的最优降解条件为50mL反应体系中接种量4.16%、温度28.20℃、初始pH值7.13、葡萄糖与胰蛋白胨浓度均为2%、OPnEO初始浓度500mg/L、180r/min培养7d,该条件下混合菌L9对OPnEO降解率达62.15%,比未优化条件提高了5%左右.     

有机胺对CO2吸收解吸的研究

利用常压搅拌吸收-解吸装置,在不同温度和浓度条件下,对MEA(乙醇胺)、DEA(二乙醇胺)、MDEA(N-甲基二乙醇胺)、TETA(三乙烯四胺)、DETA(二乙烯三胺)5种有机胺吸收解吸CO2进行研究.探讨了反应温度、吸收液浓度、有机胺种类对CO2吸收和解吸过程的影响规律,并利用正交试验法筛选出性能较好的混合胺复配剂.结果表明,当TETA/DEA=5:1,吸收温度为318K,解吸温度为388K时,混合胺具有较优的吸收解吸综合性能.     

硝化产物对硝化细菌混培物保藏特性的影响

采用添加硝化产物的方法,研究了饥饿保藏过程中硝化产物对硝化细菌混培物活性和相关性状的影响.结果表明,饥饿保藏过程中添加亚硝酸盐可改善硝化细菌混培物的保藏效果,并明显降低硝化活性的衰减速率.缺氧条件下,4℃加5mmol/L亚硝态氮、4℃加5mmol/L硝态氮及4℃不加代谢产物3种保藏方法下的硝化活性均呈指数衰减,衰减速率分别为0.010d-1、0.020d-1、0.021d-1,半衰期分别为72.3、33.9、32.7d;硝化活性趋于稳定时,3种方法下的硝化活性保留率分别为18.7%、19.1%和15.1%,总菌体量保留率分别为62.0%、47.3%和58.7%;随着饥饿保藏时间的延长,各方法下的硝化细菌混培物ATP含量和血红素c含量均随硝化活性的衰减而下降,混培物颜色也随硝化活性的衰减而变黑.     

粗苯酐与杂醇油综合利用制备增塑剂的研究

在固体酸催化下 ,粗苯酐与杂醇油直接酯化再经减压蒸馏制备邻苯二甲酸C4 ～C5混合酯增塑剂 ,经中试生产表明 ,该工艺技术是可行的 ,苯酐及C4 ～C5醇回收利用率均可达 90 %以上 ,且废水排放量很少。其最佳工艺条件为 :(1)酯化反应　 (C4 ～C5醇 )∶(苯酐 ) =2 6∶1 0 ,催化剂用量为反应物总质量的 1 5 % ,温度 110～ 16 0℃ ,时间 5h ,反应在搅拌下进行 ;(2 )减压蒸馏　蒸馏压力 <2 0kPa。     

在线超声清洗对膜生物反应器污泥混合液特性的影响

采用低功率超声波实现了膜生物反应器中膜污染的在线超声清洗,考察在线超声清洗对污泥混合液特性的影响。结果表明:在线超声清洗能有效控制膜污染,但也会导致污泥浓度和污泥活性降低,混合液过滤性能变差,上清液有机物浓度上升,污泥絮体结构破解。污泥混合液特性的恶化必然会影响膜生物反应器的稳定运行,不利于膜污染的控制。为了避免混合液特性过度恶化,每次超声清洗时间应该控制在10 min以内。