结合丙烯腈量对丁腈橡胶/炭黑硫化胶热降解性能的影响

采用热失重分析法和差示扫描量热法研究了结合丙烯腈量对丁腈橡胶/炭黑硫化胶热降解性能及热降解活化能的影响。结果表明,在降解反应初期首先发生交联环化反应,然后发生断链降解反应。交联反应放出的热量随结合丙烯腈量的增加而降低,最大放热峰温受结合丙烯腈量的影响不大。断链降解过程分为2个阶段,分别受结合丙烯腈量和丁二烯单元含量的影响。初期断链降解受腈基含量影响较大,腈基起到催化和加速降解的作用;430℃以上的失重行为与丁二烯单元的含量有关;494℃以上的降解受丁腈橡胶成炭性质的影响。不同结合丙烯腈量的丁腈橡胶/炭黑硫化胶的降解活化能趋近。     

甲基丙烯腈聚合物和共聚物的热降解研究

1、由通常游离基引发剂制备的聚甲基丙烯腈 据《P.D.S.》1994,45,285—291报导,英国学者制备了几种聚合物样品,并用TG,DTA和TVA(热挥发产物分析)等分析方法进行研究。通过TVA实验所得的降解产物的分离和分析,证明聚甲基丙烯腈单独降解或者用通常的游离基引发剂例如偶氮异丁腈、过氧化苯甲酰等引发时,几乎定量地降解成为单体,只产生(广艮)量的异丁烯和氰化氢。他们提出一种降解     

固定化菌种降解丁二腈的研究

分别用海藻酸钠与聚乙烯醇为载体,对前期研究中获得的丁二腈高效降解菌进行包埋固定。研究了不同载体包埋固定的菌种对废水中丁二腈的降解效果。结果表明,采用海藻酸钠包埋固定的菌种在30℃,pH=6.5,摇床转速为250r/min的条件下,当菌的质量浓度为lg/L和2g/L时,丁二腈的降解率均达80%以上。     

两种混合取代聚膦腈的温敏性能和降解性能研究

研究了具有甘氨酸乙酯(或苯丙氨酸乙酯)和甲氧基乙氧基乙氧基侧链的混合取代聚膦腈的温度敏感性能和降解性能。两种聚膦腈均具有较低临界溶液温度(LCST),在质量分数为2. 5% ~15%的范围内,其LCST与浓度无关。体外降解实验表明,两种聚膦腈在酸性和碱性条件下降解较快,而在pH7. 4时降解较慢。其降解产物为对机体无害的小分子。     

Fenton法降解水杨腈废水中COD和水杨酰胺的实验研究

研究采用Fenton氧化降解水杨腈废水中的水杨酰胺和COD。通过单因素实验考察双氧水用量、反应时间、绿矾用量和反应初始pH值等主要因素对废水中水杨酰胺去除率和COD去除率的影响。结果表明:Fenton法对水杨腈废水中水杨酰胺和COD的降解优化条件:pH=4.2、绿矾用量为6.8 g/L、反应时间为90 min、双氧水的用量为30.0 mL/L,在此优化条件下废水的水杨酰胺降解达到91.3%,COD的降解率达到73.8%,BOD5/COD从0.05提升到0.38,显著提高了可生化性,保障了后续生化处理的进水要求,为生产企业处理水杨腈废水提供了方向。     

极端条件驯化法提高腈水合酶产生菌的丙烯酰胺耐受性

为了提高产腈水合酶的菌体Nocardia sp.对催化产物丙烯酰胺的耐受性,利用极端条件改造了现有的丙烯酰胺生产菌株RS,通过向发酵液间歇加入丙烯腈催化生成丙烯酰胺,为菌体制造出一个极端环境,使菌体在生长催化过程中逐渐适应高浓度丙烯酰胺,强化其丙烯酰胺耐受性,驯化得到了RS-1菌株. 研究了驯化过程中菌体存活率、比死亡速率和腈水合酶活性随丙烯酰胺浓度的变化. 在不同的丙烯酰胺初始浓度(0~400 g/L)下比较了两菌株的丙烯酰胺耐受性,RS-1菌体催化丙烯腈水合的速率都大于RS菌体,平均提高30.8%;而且RS-1菌株的胞内腈水合酶也具有较好的丙烯酰胺耐受性. 在相同的水合条件下,RS-1菌株催化所得的丙烯酰胺终浓度和丙烯腈转化率分别为587.1 g/L和99.97%,都明显优于RS菌株的水合结果. 在进一步的水合实验中,RS-1菌株催化所得的丙烯酰胺终浓度达到了641.4 g/L.     

甲基丙烯腈和苯乙烯的共聚物的热降解

据《P、D、S.》1994,46,185—202报导,英国格拉斯哥大学化学系聚合物研究小组用偶氮异丁腈作为引发剂通过游离基聚合制备了甲基丙烯腈和苯乙烯的共聚物,然后用TA、DTA和TVA等分析方法研究它们的热降解行为.这些共聚物没有发生像某些     

丁腈橡胶热降解的影响因素分析

采用热重分析法对丁腈橡胶(NBR)热降解的影响因素进行分析。结果表明:交联可加快NBR热降解,降低热降解温度;生胶门尼粘度对NBR热降解无影响;随着丙烯腈质量分数的增大,NBR最大降解速率温度降低,最大质量损失速率减小;升温速率较小时,丙烯腈质量分数对最大质量损失速率和最大降解速率温度的影响较大;升温速率增大,最大降解速率温度升高,丙烯腈质量分数越大,最大降解速率温度受升温速率的影响越大,升温速率对最大质量损失速率的影响恰好相反;与氮气气氛相比,空气气氛下炭黑/NBR硫化胶的降解温度升高,降解速率减小。     

己二腈的生产现状及市场分析

对己二腈的几种主要生产工艺进行了评述,包括丙烯腈电解二聚法、己二酸催化氨化法、丁二烯法和己二酰胺降解水解法。对己二腈的需求和市场情况进行了分析。     

纳米TiO2光催化降解溴虫腈

用溶胶-凝胶法制备了纳米级TiO2和不同掺铁量的TiO2纳米粒子,用XRD、TEM、FTIR等手段对其进行了表征。将制备的TiO2和掺铁TiO2纳米粒与溴虫腈农药配制成悬浮液,分别作光降解实验。结果表明,掺铁TiO2对溴虫腈的光催化降解速率较TiO2高,随着铁离子浓度的增大,溴虫腈的降解率先上升后下降,最大催化活性的掺铁量为n(Fe3+)/n(TiO2)=0.08,TiO2在酸性或碱性条件下对溴虫腈的光催化活性较中性高,而掺铁TiO2随着溴虫腈悬浮液pH升高催化活性下降。该研究为农药纳米功能化制剂的制备,及利用光催化降解农药减少环境污染提供了实验依据。     

n-Hexadecane and pyrene biodegradation and metabolization by Rhodococcus sp. T1 isolated from oil contaminated soil

The high-molecular weight polycyclic aromatic hydrocarbons(PAHs) pyrene and typical long chain alkane nhexadecane are both difficult to degrade. In this study, n-hexadecane and pyrene degrading strain Rhodococcus sp. T1 was isolated from oil contaminated soil. Strain T1 could remove 90.81% n-hexadecane(2 vol%) and 42.79% pyrene(200 mg·L~(-1)) as a single carbon within 5 days, respectively. Comparatively, the degradation of pyrene increased to 60.63%, but the degradation of n-hexadecane decreased to 87.55% when these compounds were mixed. Additionally, identification and analysis of degradation metabolites of Rhodococcus sp. T1 in the above experiments showed that there were significant changes in alanine, methylamine, citric acid and heptadecanoic acid between sole and dual substrate degradation. The optimal conditions for degradation were then determined based on analysis of the pH, salinity, additional nutrient sources and liquid surface activity.Under the optimal conditions of pH 7.0, 35 °C, 0.5% NaCl, 5 mg·L~(-1) of yeast extract and 90 mg·L~(-1) of surfactant,the degradation increased in single or dual carbon sources. To our knowledge, this is the first study to discuss metabolite changes in Rhodococcus sp. T1 using sole substrate and dual substrate to enhance the long-chain alkanes and PAHs degradation potential.     

高效苯酚降解菌群的选育及降解特性研究

通过富集驯化获得具有高效降解苯酚能力的苯酚降解菌群PDBC-1,对菌群降解苯酚的性能及影响因素进行了分析。结果表明,红球菌属细菌是该菌群中的优势菌种。在初始苯酚质量浓度低于1 200mg/L时,菌群能够在72 h内完全降解苯酚,但在更高苯酚浓度下,苯酚对菌群生长造成明显抑制,苯酚降解能力显著下降。该菌群降解苯酚的适宜盐度为0~5%,温度为25~40℃,pH为7.0~8.0。     

丙烯腈生产的高效精制工艺优化

采用阳离子交换树脂D001去除丙烯腈中(口恶)唑。D001的平衡吸附量为37.08 mg·g-1,在20℃、30℃、40℃、50℃下,D001对(口恶)唑的吸附符合Langmuir吸附等温方程。在进料流量为2.0 BV·h-1、体系温度为20℃时,丙烯腈中(口恶)唑的去除率达99％以上。采用5％的HCl为洗脱剂,在其用...     

化学法丙烯酰胺生产中原料精制工艺技术研究

采用阴离子交换树脂去除生产丙烯酰胺的主要原料丙烯腈中的氢氰酸,该树脂的吸附量为37.08 mg/g,氢氰酸的吸附率达99%以上,脱附率可达100%。在丙烯酰胺生产工艺中,增加离子交换树脂吸附氢氰酸精制工艺部分,可使主要原料丙烯腈氢氰酸的含量控制在1 mg/g以下,可以降低原料丙烯腈中氢氰酸对生产丙烯酰胺产品质量的影响。     

高效优势降解菌处理樟脑废水

针对樟脑废水,从活性污泥中筛选出降解樟脑废水的高效优势菌,通过分离纯化,优选出3株适应能力强、生长旺盛的菌株,分别为ZH-1、ZH-2、TZH-2。经初步鉴定分别为动胶菌属、假单胞菌属、短杆菌属。试验测定了樟脑混合菌最佳生长条件的优化组合为:葡萄糖质量浓度20 g.L-1,温度30℃,pH值为7,转速为125 r.m in-1,培养时间55 h。并测定了单株菌和混合菌对樟脑废水的降解效果,结果表明混合菌的降解效果最为明显,降解率为75.23%。     

湿法腈纶生产的含腈废水处理实验研究

采用不同方法对湿法腈纶废水进行预处理，比较了它们的处理效果和特点。研究中使用的菌种预处理方法达到了理想的效果，废水中大分子有机污染物被迅速、高效地分解为挥发性脂肪酸和氨氮等，为后续的接触氧化以及反硝化创造了良好的条件，COD和TKN的总去除率分别为92％和85％，最终出水达到或优于行业二级排放标准。     

炼厂油泥降解菌的筛选及降油条件初探

从某炼厂的土壤和处理水中筛选到了3株降解炼厂油泥中原油效果较好的菌株T1、A2、Z8,其中菌株T1对原油的降解效果最好。初步研究了菌株T1的培养条件以及降解原油的条件。结果表明,菌株T1的最佳培养条件为:温度30℃、转速160r·min-1、pH值9.0;最佳的培养基组成(g·L-1)为:葡萄糖25、NaCl 3.0、(NH4)2SO41.0、NaNO31.0、KH2PO44.0、K2HPO4·3H2O 25.0,与其它无机盐相比,K2HPO4·3H2O对T1菌株降解油泥的影响最大。在最佳条件下,第一代T1菌株对油泥中原油的降解率达71.3%。     

Combination of a crude oil-degrading bacterial consortium under the guidance of strain tolerance and a pilot-scale degradation test

Under the guidance of strain tolerance, a new combinationmethod for crude oil-degrading bacterial consortium was studied. Firstly,more than 50 efficient crude oil-degrading and biosurfactant producing bacteriawere isolated from petroleum-contaminated soil andwater in Tianjin Binhai New Area Oilfield, China. Twenty-four of them were selected for further study. These strains were identified as belonging Pseudomonas aeruginosa, Bacillus subtilis, Brevibacillus brevis, Achromobacter sp., Acinetobacter venetianus, Lysinibacillus macroides, Klebsiella oxytoca, Stenotrophomonas rhizophila, Rhodococcus sp. and Bacillus thuringiensis. A shake-flask degradation test revealed that 12 of these strains could degrade over 50% of 1% crude oil concentration in 7 d. Of these, 8 strains were able to produce biosurfactants. Furthermore, environmental tolerance experiments indicated that the majority of the strains had the ability to adapt to extreme environments including high temperatures, alkaline environments and high salinity environments. A mixed bacterial agent comprising the strains WB2, W2, W3 and HA was developed based on the environmental tolerance tests and subjected to the pilot-scale degradation test indicating that this bacterial agent could degrade 85.2% of 0.8% crude oil concentration in 60 d. Our results suggest that the application of this mixed agent could remediate crude oil polluted soils in saline and alkaline environments.     

红平红球菌LSSE8-1中辅因子再生系统的构建

采用PCR方法从红球菌Rhodococcus sp. RHA1基因组中克隆了编码甲酸脱氢酶的基因(fdh),将该基因片段插入大肠杆菌-红球菌穿梭质粒pBS306,构建了甲酸脱氢酶表达质粒pBS-PFG,转入专一性脱硫菌R. erythropolis LSSE8-1,得到重组菌LSSE8-1-FDH. 2,3,5-三苯基氯化四氮唑(TTC)显色反应测得重组菌LSSE8-1-FDH的总脱氢酶活(OD496)为0.464,原始菌LSSE8-1的总脱氢酶活(OD496)为0.353,重组菌比原始菌酶活增加了31%. 考察了不同浓度甲酸根对R. erythropolis LSSE8-1与重组菌LSSE8-1-FDH生长的影响,当甲酸根浓度为25 mmol/L时重组菌LSSE8-1-FDH的生长最佳. 油水相静息细胞脱硫实验表明,重组LSSE8-1-FDH菌比宿主菌的脱硫速率增加了12.5%,总脱硫率增加了约20%.     

Determination of degradation rate of acrylonitrile polymers

Low‐temperature degradations of acrylonitrile homopolymers and acrylonitrile/acrylamide copolymers in air were investigated by IR and thermogravimetry. The degradation rates of acrylonitrile polymers were determined by measurement of normalized absorbance of ? C?N band and effects of the degradation temperature, time, and comonomer on the rate of degradations were discussed. It was found that the polymers start to degrade as the temperature increased to 150°C. In the temperature range of 180–210°C, values of the rate of polymer degradation were maximal and the rate of degradation of acrylonitrile/acrylamide copolymers was higher compared with that of acrylonitrile homopolymers. At 150°C, acrylonitrile homopolymers had an induction period of about 0.5 h. The rate of degradation of acrylonitrile/acrylamide copolymers showed an obvious trend of increase along with acrylamide concentration, and changes of the rate became less prominent as the weight ratio of acrylamide/acrylonitrile went beyond 5/95. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1511–1514, 2006