臭氧预氧化-BAF深度处理造纸废水

采用臭氧预氧化-BAF工艺对某钞票纸厂废水进行深度处理.结果表明,臭氧预氧化处理能提高废水的可生化性,废水经臭氧预氧化-BAF工艺处理后(臭氧用量100 mg/L,臭氧与废水接触时间5 min,BAF水力停留时间2.0h)出水CODCr浓度约40 mg/L,色度几乎完全去除,能够达到较高的废水排放标准或作为中水回收利用.     

超效浅层气浮生物接触氧化工艺处理废纸造纸废水

采用超效浅层气浮生物-接触氧化工艺处理废纸造纸废水,在进水CODCr、SS、BOD5分别为1200mg/L、800mg/L和300mg/L的情况下,经过该工艺处理后,出水CODCr、SS、BOD5分别为64.8mg/L、20mg/L和30mg/L.     

气浮-接触氧化-混凝沉淀处理制革废水

采用气浮-接触氧化-混凝沉淀工艺处理某制革厂制革废水,经过一年多稳定运行表明,在进水CODCr、BOD5和SS分别为2500mg／L、1000mg／L、1200mg／L情况下,处理后出水CODCr、BOD5和SS质量浓度分别为75～84mg／L、18-26mg／L、62-70mg／L,达到了一级标准。该废水处理工艺有工程投资省、运行费用低、处理效果好等特点。     

Mn-Ce/Al_(2)O_(3)催化剂臭氧催化氧化深度处理漂染废水探析

针对某漂染企业生化出水提标改造的需求,以活性氧化铝为载体,以Mn为活性组分并掺杂稀土元素Ce构建复合催化剂,臭氧催化氧化深度处理漂染废水。实验结果表明,分散红模拟废水,CODCr为300 mg/L、废水体积为1 L时,活性组分Mn占催化剂总质量浓度的10%,催化剂投加量为10 g/L,臭氧浓度为250 mg/L,臭氧流量为50 mL/min,臭氧催化氧化60 min后,废水中CODCr、TOC的去除率分别为98.4%、97.1%。采用Mn-Ce/Al_(2)O_(3)催化剂臭氧催化氧化法深度处理实际漂染废水,出水的CODCr均低于50 mg/L,达到企业废水深度处理的要求。     

微电解与Fenton氧化联合降解印染退浆废水研究

本研究采用改性微电解材料与Fenton氧化、混凝工艺联合处理印染退浆废水.研究结果表明:微电解/Fenton/混凝为最佳组合工艺,出水B/C为0.44.利用该工艺处理CODCr 5315 mg/L、PVA 0.68 g/L、B/C 0.10的印染退浆废水,废水pH调至4、微电解材料一次投加量465 g/L、停留时间60...     

壳聚糖丙烯酰胺接枝共聚物的制备及其与Fenton氧化法联合处理麦草浆中段废水

以硝酸铈铵为引发剂,合成了壳聚糖丙烯酰胺接枝共聚物（CAM）;结果表明,当m（丙烯酰胺）∶m（壳聚糖）=3∶1,c（硝酸铈铵）=3 mmol/L,反应温度为60℃时,合成的CAM接枝率达到239.4%,单体转化率达到79.83%;将其与Fenton试剂联用,可处理麦草浆中段废水。Fenton氧化预处理的最佳工艺为：ρ（H2O2）=2 g/L,m（H2O2）∶m（FeSO4）=2∶1,pH=4,处理时间为60 m in。絮凝阶段处理的最佳工艺为：ρ（CAM）=10 mg/L,在此条件下,处理后麦草浆中段废水CODCr去除率达82.38%,浊度去除率达到98.53%。     

SR-AOPs深度处理制浆造纸废水的研究

采用由高级氧化塔、离子沉淀池、V型砂滤池组成的基于亚铁离子(Fe2+)活化过硫酸盐(PS)产生硫酸根自由基(SO4-·)的高级氧化工艺(SR-AOPs)深度处理制浆造纸废水二级出水(CODCr为85～110 mg/L).结果表明,SR-AOPs对制浆造纸废水二级出水有很好的处理效果,最优工艺条件为:PS用量1.5 mmol/L,Fe2+用量2.25 mmol/L,n(PS)∶n(Fe2+) =2∶3.在该条件下,出水CODCr为31.2 mg/L,CODCr去除率达到70％,出水SS低于5 mg/L,SO42-浓度为203.5 mg/L,出水水质达到GB3544-2008制浆造纸废水排放标准,废水处理成本约为2.831元/t.     

基于硫酸根自由基的高级氧化技术深度处理造纸废水的研究

采用零价铁(ZVI)活化过硫酸钠(PS)产生硫酸根自由基的高级氧化技术处理造纸废水二级出水(CODCr为160 mg/L,色度为200度),考察了常温下pH值、ZVI用量、PS用量等因素对CODCr降解率及色度去除率的影响,并对其降解过程动力学进行了探讨,初步确定了硫酸根自由基氧化降解造纸废水的工艺条件,通过采用GC-MS检测分析了废水处理前后的物质变化情况。结果表明,在酸性至中性条件下,硫酸根自由基皆可有效降解有机污染物;在ZVI用量为8 g/L、PS用量为4 g/L时,室温条件下反应3h后,初始pH值为3和未调节pH值废水的CODCr降解率分别达到57.5%和34.2%,色度去除率分别达到83%和89%;通过GC-MS检测分析可知二级出水中含35种有机污染物,经过硫酸根自由基氧化降解后废水中苯类物质得到了一定的降解,相对含量有一定的变化,但种类基本没变。     

IC厌氧反应器-改良型氧化沟-浅层气浮工艺处理制浆造纸废水

采用IC厌氧反应器-改良型氧化沟-浅层气浮工艺处理制浆造纸废水,介绍和分析了整个工艺的主要构筑物及其调试运行方法.当进水CODCr为4000 mg/L、BOD5为1350 mg/L、SS为2000mg/L时,出水CODCr,≤60 mg/L、BOD5≤20 mg/L、SS≤30 mg/L,达到GB3544-2008造纸工业水污染物排放标准的污染物排放限值.     

臭氧预氧化-BAF深度处理造纸废水

采用臭氧预氧化-BAF工艺对某钞票纸厂废水进行深度处理.结果表明,臭氧预氧化处理能提高废水的可生化性,废水经臭氧颅氧化-BAF工艺处理后(臭氧用量100 mg/L.臭氧与废水接触时间5 min,BAF水力停留时间2.0 h)出水CODcr浓度约40 mg/L,色度几乎完全去除,能够达到较高的废水排放标准或作为中水回收利用.     

复合氧化剂法合成氧化玉米淀粉

以玉米淀粉为原料,过氧化氢和过硫酸钾为复合氧化剂,Fe~(2+)为催化剂,在酸性条件下以湿法工艺合成氧化玉米淀粉。以淀粉质量分数、复合氧化剂比例、复合氧化剂质量分数(占干淀粉总量)、催化剂质量分数(占干淀粉总量)、反应温度、反应时间等因素为变量,以羧基含量作为氧化度衡量指标,采用单因素试验和正交优化试验,确定制备氧化玉米淀粉最佳工艺条件为:淀粉质量分数35%、复合氧化剂质量分数8%、复合氧化剂比例[m(H_2O_2):m(K_2S_2O_8)]为4:1、体系pH 4.00、催化剂质量分数0.3%、反应温度50℃、反应时间1.5 h,在此条件下,可合成氧化度为0.118%氧化玉米淀粉。     

Chemical nitrite oxidation in acid solutions as a consequence of microbial ammonium oxidation

In long-term experiments with membrane aerated biofilm reactors we observed complete nitrite oxidation in highly concentrated ammonium nitrite solutions with a contaminant pH decrease to values below 3. The maximum initial concentration for ammonium was 42 mM and for nitrite was 41 mM. We hypothesized that (1) acid-tolerant ammonium oxidizing bacteria were responsible for the pH decrease, and (2) chemical processes caused complete nitrite oxidation at low pH values. To test this hypothesis we set up a mechanistic computer model based on kinetic data from literature and we validated the model with additional experiments. The simulations fitted the measurements very well. Additionally, an experiment with the inhibitor allylthiourea showed that ammonium-oxidizing bacteria were active at pH values far below 5.5. Experiments in a sterile reactor confirmed the chemical nitrite oxidation to nitrate. Nitrogen balances revealed that 8 +/- 4% of the initial nitrogen (ammonium, nitrite, and nitrate) were lost during the cycles. On the basis of measurements and simulations we concluded that volatilization was responsible for the significant nitrogen loss. We estimated that about half of the lost nitrogen volatilized as nitrous acid HNO2. The rest mainly volatilized as dinitrogen N2 and nitrous oxide N2O.     

蒸煮腌肉色素氧化与脂肪氧化互促效应关系的研究动态

色泽是肉及肉制品的最重要的一个品质指标,因为它是消费者用来判断其新鲜度和是否购买的一个最直观的指标.蒸煮腌肉制品在贮藏过程中会发生褪色,主要是蒸煮腌肉色素(CCMP)的降解和氧化所致,其中脂肪氧化与CCMP的氧化关系密切,许多有关脂肪氧化与肉色变化之间的关系问题还不很明确.本文主要综述了CCMP氧化与脂肪氧化之间的相互诱导和激发、促使关系研究现状,为研究蒸煮腌肉制品贮藏期间色泽变化理论以及确定有效的护色技术提供一些指导.同时,肉类研究者在发展新型稳定肉色方法的同时,需更进一步关注CCMP的化学变化理论研究.     

Determination of thermal oxidation and oxidation products of β-carotene in corn oil triacylglycerols

A reversed phase HPLC-DAD coupled to APCI-MS method is reported for the determination of the degradation of β-carotene and characterization of the oxidation products in corn oil. Corn oil containing β-carotene was oxidized in the Rancimat at 110 °C from 1 to 14 h. A significant degradation of β-carotene was observed in corn oil during accelerated thermal oxidation. A total of eight different oxidized products of β-carotene were identified, which includes 8′-apo-β-carotenal, 6′-apo-β-carotenal, 5,6-epoxy-8′-apo-β-carotenal, β-carotene-2,2′-dione, 13-Z-5,6,5′,6′-diepoxy-β-carotene, all-E-5,8-epoxy-β-carotene, all-E-5,6-epoxy-β-carotene, and 15-Z-5,6-epoxy-β-carotene. Corn oil triacylglycerols (TAGs) oxidation products were also identified using isocratic HPLC–ESI-MS. It was found that β-carotene promoted oxidation of TAGs especially at longer exposure times. For the first time two new classes of oxidized TAGs have been identified in corn oil, which were epidioxy bis-hydroperoxides and hydroxy bis-hydroperoxides. Other oxidation products of TAGs were mono-epoxides, mono-hydroperoxides, and epoxy hydroperoxides. It was found that complementing the HPLC-DAD method for β-carotene with ESI-MS method for TAGs oxidation provides a comprehensive set of analytical tools to characterize carotenoids and triacylglycerols oxidation and degradation in edible oils.     

油脂OSI加速氧化条件下氧化机制初探

对Rancimat加速氧化试验中葵花籽油的氧化指标进行跟踪检测,测定0、1.5、3.0、4.5、6.0、7.5、9.0 h油样的酸价、过氧化值、茴香胺值及总氧化值等指标,通过与室温(25℃)、40、60、100℃的烘箱试验的氧化指标数据进行对比,从理论上确认了OSI(100℃)法对于指导油脂常温存储的可靠性。研究结果表明:油脂在OSI(100℃)、40℃烘箱、60℃烘箱与室温下氧化机制相似,即上述加速氧化方法均能准确反映室温下油脂氧化动力学特征。     

Supercritical water oxidation of sulfide

Supercritical water oxidation (SCWO) of sulfide wastewater with oxygen as the oxidant was investigated using ammonium sulfide solution as the model waste. The experiments, which were conducted in a bench-scale continuous SCWO installation, indicated that S2- could be completely oxidized to SO4(2-) within the residence time of less than 10 s under the supercritical water conditions at 698.2-773.2 K and 22.0 MPa-30.0 MPa. The reaction pathway of S2- in SCWO was determined to be S2- --> S2O3(2-) --> SO3(2-) --> SO4(2-). The effects of temperature, pressure, and oxygen content on SCWO of S2- were also studied. The kinetic model based on this pathway was established with the reaction rate constants and orders found by fitting the experimental data. The dependence of the rate constants on the temperature can be described with Arrhenius' law. The rate constants are dependent on the density of SCW, and the dependence is logarithmically linear.     

Kinetics of diesel nanoparticle oxidation

The technique of high-temperature oxidation tandem differential mobility analysis has been applied to the study of diesel nanoparticle oxidation. The oxidation rates in air of diesel nanoparticles sampled directly from the exhaust stream of a medium-duty diesel engine were measured over the temperature range of 800-1140 degrees C using online aerosol techniques. Three particle sizes (40, 90, and 130 nm mobility diameter) generated under engine load conditions of 10, 50, and 75% were investigated. The results show significant differences in the behavior of the 10% load particles as compared to the 50 and 75% load particles. The 10% load particles show greater size decrease at temperatures below 500 degrees C and significant size decrease at temperatures between 500 and 1000 degrees C in a non-oxidative environment, indicating release of adsorbed volatile material or thermally induced rearrangement of the agglomerate structure. Activation energies determined are 114, 109, and 108 kJ mol(-1) for the 10, 50, and 75% load particles, respectively. These activation energies are lower than for flame soot (Higgins et al. J. Phys. Chem. A 2002, 106, 96), but the preexponential factors are lower by 3 orders of magnitude, and the overall oxidation rates are slower by up to a factor of 4 over the temperature range studied. Possible reasons for the differences are discussed in the text.     

亚麻纤维的选择性氧化

采用高碘酸钠对亚麻纤维进行选择性氧化,可使纤维素链单元的2个仲羟基氧化成醛基,红外光谱图证实了活性醛基的生成。在高碘酸钠选择性氧化纤维素过程中,影响氧化程度的因素主要有高碘酸钠质量浓度、氧化时间等。研究了氧化时间和高碘酸钠质量浓度对氧化亚麻纤维醛基含量、失重率和力学性能的影响。结果表明:增加高碘酸钠质量浓度、延长氧化时间,亚麻纤维中的醛基含量增加,但亚麻纤维的失重率增加。随着氧化程度的加深,亚麻纤维的断裂强度逐渐降低。     

Pigment oxidation in ground veal: Influence of lipid oxidation, iron and zinc

The color stability of fresh ground veal from four different muscles (biceps femoris, longissimus dorsi, psoas major and supraspinatus) was characterized, and the effects of lipid oxidation, iron and zinc on this degradative process were investigated. Samples were minced and prepared in a manner consistent with retail production and analyzed for pH, myoglobin concentration, total and nonheme iron, and zinc. Pigment and lipid oxidation were measured on days 0, 3 and 6 of 4°C storage. B. femoris demonstrated the greatest extent of lipid oxidation, and was more color-labile than p. major or supraspinatus (P < 0·05), but no different from l. dorsi (P > 0·05). Total iron and myoglobin concentrations were lowest for l. dorsi (P<0·05). Zinc concentration in the four muscles followed the order supraspinatus ? b. femoris ? l. dorsi ? p. major (P < 0·05). Data analysis revealed that initial metmyoglobin formation (days 0 to 3) was significantly correlated with total iron (r = 0·69) or nonheme iron (r = 0·68) in b. femoris, but not any of the other muscles. Correlations between lipid and pigment oxidation in each of the four muscles were performed and the data support a strong relationship between these degradative processes in ground veal.