Fenton氧化法预处理高浓度制药废水的实验研究

采用Fenton法对高浓度制药废水进行预处理实验。主要考察了Fenton试剂氧化法预处理高浓度制药废水的影响因素,主要讨论pH值、FeSO4·7H2O投加量、反应时间对Fenton氧化工艺对制药废水中CODCr处理效果的影响。实验结果显示,pH值为4、反应时间100 min、FeSO4·7H2O投加量为0.024 mol/L、H2O2/Fe2＋投加比为11∶1,CODCr处理去除率为52.1%,可生化性BOD/COD为0.57,效果最为理想。     

超声波强化Fenton试剂深度处理山梨酸废水的研究

采用超声强化Fenton(Fe2++H2O2)试剂,耦合氧化深度处理山梨酸废水。考察了超声功率、反应时间、反应温度、pH值、试剂投加量对CODCr去除率的影响。结果表明:在超声频率40kHz,超声功率400W,反应时间40min、反应温度60℃、pH值3.0、H2O2浓度0.22mol/L、Fe2+浓度0.04mol/L时,CODCr去除率达到95%以上。与单独使用Fenton试剂法相比,该方法反应时间短、反应温度低、试剂投加量小、CODCr去除率高。     

Fenton氧化–曝气生物滤池处理电镀铜镍废水的研究

采用Fenton氧化–曝气生物滤池(BAF)组合工艺对电镀铜镍废水进行了处理。研究了初始pH、ρ(Fe2+)/ρ(H2O2)比值以及H2O2投加量对CODCr去除率的影响,并对该组合工艺进行了经济分析。试验结果表明,经该组合工艺处理后,废水中CODCr去除率达到86%,Cu2+、Ni2+浓度均符合相关排放标准。     

Fenton试剂预处理农药废水实验

对Fenton氧化法预处理农药废水进行了研究,通过考察H2O2投加量、[Fe2 ]/[H2O2](摩尔比)、pH值、反应时间、Fenton试剂投加方式等因素对该农药废水化学需氧量(CODcr)、色度去除率的影响,确定了反应的最佳条件:即H2O2的投加量为50 mmol/L,[Fe2 ]/[H2O2]为1:10,pH值为3,反应时间为2h,Fenton试剂分4次投加.在此条件下CODcr去除率可达68.07%、色度去除率可达90.11%;Fenton氧化预处理后废水的可生化性也得到了大大提高.     

Fenton氧化法深度处理草浆造纸废水的研究

采用Fenton氧化法深度处理经厌氧、好氧处理后的草浆造纸废水,通过正交实验和单因素试验,研究了各主要因素对废水CODCr去除效果的影响,确定了最佳工艺条件。结果表明:在进水CODCr为415 mg/L、pH=3、H2O2投加量为30 mmol/L、Fe2+投加量为5 mmol/L、反应时间为50 min时,废水CODCr的去除率达85.49%,出水CODCr降到61 mg/L以下。     

氧化-絮凝-A/O处理甲基多巴生产废水研究

甲基多巴是一种降压药物,其生产废水具有高色度、高有机物浓度和生物难降解的特性.采用Fenton氧化-PAM絮凝-A/O生化工艺处理该废水.Fenton氧化处理的优化条件为:pH 5.0,n(Fe2 )∶n(H2O2)=1∶4,H2O2和绿矾投加质量浓度分别为5.0 g/L和10.2 g/U,反应时间2.0 h.PAM絮凝处理的优化条件为:pH 7.0,投加量16.7mg/L.经过Fenton氧化-PAM絮凝处理,CODCr去除率达到74%,脱色率达95%,B/C由0.17升到0.38,废水的可生化性明显提高.后续采用A/O工艺进一步处理,可再去除70%～80%的CODCr.     

萃取-Fenton氧化法预处理富马酸生产废水

采用萃取-Fenton氧化相结合的工艺来预处理富马酸生产废水,考察了萃取剂种类、油水体积比、萃取剂与稀释剂体积比、萃取反应pH值、温度等因素对萃取效果的影响,同时研究了Fenton氧化法对萃取后废水的进一步处理效果,结果表明：以磷酸三丁酯为络合萃取剂,异辛醇为稀释剂,最佳油水体积比为0.8,最佳稀释体积比为V（萃取剂）∶V（稀释剂）=3∶1,最佳pH值为废水初始pH值,一次萃取废水CODCr去除率为73%;对萃取后废水采用Fenton氧化法进一步处理,H2O2投加量为9/5 Qth（理论投加量）,n（Fe2＋）∶n（H2O2）=1∶4,反应最佳pH值为3,反应时间为1 h,处理后废水CODCr质量浓度降至1 000 mg/L,总的CODCr去除率达到96.5%。     

曝气微电解-Fenton氧化处理制药废水实验研究

通过曝气微电解-Fenton氧化对制药废水进行了实验研究。研究表明,曝气微电解-Fenton氧化法的最佳工况条件为：铁炭质量比为1∶1、进水pH为2.5～3.0、曝气微电解反应时间为60 min、H2O2投加量为5 mL/L、Fenton氧化反应时间为90 min。在此反应条件下,整个曝气微电解-Fenton氧化-混凝沉淀过程CODCr去除率为93.2%～95.9%,出水各项指标可达到《污水综合排放标准》（GB8978-1996）中一级标准。     

蒸发与Fenton试剂联用处理环氧氯丙烷废水的研究

针对环氧氯丙烷废水含盐量高、难降解等特点,采用蒸发-Fenton试剂氧化法联合对环氧氯丙烷废水进行处理,考察了pH值、H2O2投加量、Fe2+投加量、反应时间、反应温度等因素对CODCr去除率的影响。结果表明,当pH值为3.0、H2O2浓度为2.50 g/L、Fe2+浓度为1.84 g/L、反应时间为60 min、反应温度为60℃时,废水CODCr去除率可达90.4%。     

超声-Fenton法协同处理生化后制药废水研究

研究在酸性环境下,超声协同Fenton技术对废水有机物的去除,同时考察p H、H2O2浓度、Fe2+浓度、超声功率和反应时间等因素对降解生化后发酵制药废水的影响。结果表明:Fenton试剂辅以超声作用后,CODCr去除效果优于单独超声、单独Fenton法;同时确定了超声-Fenton氧化法降解生化后发酵制药废水最佳工艺参数:在超声波功率为75 W、溶液p H为4.0、H2O2浓度为4.70 mmol/L,Fe2+浓度为6.50 mmol/L,反应时间为30 min条件下,CODCr最高去除率可达到71.5%,色度去除率可达到97%。     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.