Citrobacter sp. CK3对活性红KN-3B的脱色反应动力学研究

采用脱色菌Citrobacter sp. CK3,以活性红KN-3B染料为处理对象,在厌氧批式反应条件下,系统考察了pH值,温度和染料浓度对脱色反应速度的影响;通过动力学模拟及反应过程中染料的UV-Vis扫描图分析,探讨了脱色反应机理。结果表明：Citrobacter sp. CK3对活性红KN-3B的脱色反应的适宜pH为7～9;脱色反应速度在温度为32℃时达到最大。染料初浓度从57 mg/L逐渐增大到458 mg/L时脱色率逐渐降低。脱色过程中染料的偶氮键发生断裂,脱色反应符合二级反应动力学。     

Influence of the initial state of carbon nanotubes on their colloidal stability under natural conditions

The colloidal stability of dry and suspended carbon nanotubes (CNTs) in the presence of amphiphilic compounds (i.e. natural organic matter or surfactants) at environmentally realistic concentrations was investigated over several days. The suspensions were analyzed for CNT concentration (UV-vis spectroscopy), particle size (nanoparticle tracking analysis), and CNT length and dispersion quality (TEM). When added in dry form, around 1% of the added CNTs remained suspended. Pre-dispersion in organic solvent or anionic detergent stabilized up to 65% of the added CNTs after 20 days of mild shaking and 5 days of settling. The initial state of the CNTs (dry vs. suspended) and the medium composition hence are critical determinants for the partitioning of CNTs between sediment and the water column. TEM analysis revealed that single suspended CNTs were present in all suspensions and that shaking and settling resulted in a fractionation of the CNTs with shorter CNTs remaining predominantly in suspension.     

反相乳液聚合制备阳离子聚丙烯酰胺及其絮凝性能评价

研究了单体浓度、单体配比、反应温度、引发剂用量等因素对所制备的阳离子聚丙烯酰胺特性粘度、转化率、阳离子度的影响,并对产品的污水絮凝性能进行了评价。较佳的制备条件为:单体浓度为45%,单体配比为7∶3,引发剂用量m(引发剂)/m(单体)为0.5%,引发温度为45℃。用红外光谱对共聚物进行了结构表征,结果表明聚合物中有六元氮杂环的存在,达到预定要求。对共聚物进行了油田污水絮凝性能评价,研究表明单独使用自制阳离子聚丙烯酰胺(CPAM)时浊度的去除率为86.22%,COD去除率为87.95%,与聚合氯化铝复配使用时浊度去除率提高到92.91%,COD去除率提高到92.68%。     

Preparation, characterization, and photocatalytic activities of boron- and cerium-codoped TiO2

Boron- and cerium-codoped TiO2 photocatalysts were synthesized using modified sol-gel reaction process and characterized by X- ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, particle size distribution （PSD）, diffuse reflectance spectra （DRS）, and Brunauer-Emmett-Teller （BET）. The photocatalytic activities were evaluated by monitoring the degradation of dye Acid Red B （ARB）. The results showed that the prepared photocatalysts were mixed oxides mainly consisting of titania, ceria, and boron oxide. The structure of TiO2 could be transformed from amorphous to anatase and then to rutile by increasing calcination temperature; the transformation being accompanied by the growth of particle size without any obvious change in phase structure of CeO2. The XPS of B1.6Ce1.0-TiO2 prepared at 500℃ showed that a few boron atoms were incorporated into titania and ceria lattice, whereas others existed as B2O3. Cerium ions existed in two states, Ce^3＋ and Ce^4＋, and the atomic ratio of Ce^3＋/Ce^4＋ was 1.86. When boron and cerium were doped, the UV-Vis adsorption band wavelength showed an obvious shift toward the visible range （〈526 nm）. As the atomic ratio of Ce/Ti increased to 1.0, the absorbance edge wavelength increased to 481 nm. The absorbance edge wavelength decreased for higher cerium doping levels （Ce/Ti=2.0）. The particles size ranged from 122 to 255 nm with a domain at 168 nm （39.4%）. The degradation of ARB dye indicated that the photocatalytic activities of boron- and cerium-codoped TiO2 were much higher than those of P25 （a standard TiO2 powder）. The activities increased as the boron doping increased, whereas decreased when the Ce/Ti atomic ratio was greater than 0.5. The optimum atomic ratio of B/Ti and Ce/Ti was 1.6 and 0.5, respectively.     

质子化焦化污泥作为生物吸附剂对水溶液中活性红4的吸附性能

以焦化厂污水处理车间的剩余污泥为材料,经过质子化处理制备生物吸附剂,进行了吸附活性红4(RR4)的研究. 考察了吸附平衡时间,溶液pH,染料质量浓度,NaCl浓度等因素对RR4吸附的影响. 结果表明:生物吸附剂对RR4的吸附所需平衡时间为48 h;溶液的pH对吸附过程有较大影响,酸性条件利于吸附,碱性条件下发生解吸附(解吸附率大于70%);吸附等温曲线符合Langmuir和Freundlich方程, pH=1的条件下最大吸附量为(72.33±5.59) mg/g;ρ(RR4)为100 mg/L时,NaCl浓度对RR4的吸附不产生可见影响,ρ(RR4)为500 mg/L时,NaCl的存在对吸附有阻碍作用.      

Removal of total cyanide in coking wastewater during a coagulation process：Significance of organic polymers

Whether a cationic organic polymer can remove more total cyanide （TCN） than a non-ionic organic polymer during the same flocculation system has not been reported previously. In this study, the effects of organic polymers with different charge density on the removal mechanisms of TCN in coking wastewater are investigated by polyferric sulfate （PFS） with a cationic organic polymer （PFS-C） or a non-ionic polymer （PFS-N）. The coagulation experiments results show that residual concentrations of TCN （Fe（CN）6^3-） after PFS-C flocculation （TCN 〈 0.2 mg/L） are much lower than that after PFS-N precipitation. This can be attributed to the different TCN removal mechanisms of the individual organic polymers. To investigate the roles of organic polymers, physical and structural characteristics of the floes are analyzed by FT-IR, XPS, TEM and XRD. Owing to the presence of N＋ in PFS-C, Fe（CN）3- and negative flocs （Fe（CN）63- adsorbed on ferric hydroxides） can be removed via charge neutralization and electrostatic patch flocculation by the cationic organic polymer. However, non-ionic N in PFS-N barely reacts with cyanides through sweeping or bridging, which indicates that the non-ionic polymer has little influence on TCN removal.     

HDTMA改性粘土对模拟地下水中苯系物的吸附

以季铵盐（QAC）阳离子表面活性剂十交烷基三甲基铵离子（HDTMA）改性膨润土和凹凸棒土,研究它们对模拟地下水中的苯、甲苯、二甲苯的吸附作用.结果表明,两种HDTMA改性粘土矿物的有机质含量分别提高了54．8和404.5倍,它们可以有效地吸附模拟地下水中的苯系物,吸附量比原粘土矿物高出几十全几百倍对苯、甲苯、二甲苯来说,改性凹凸棒土和膨润士的吸附系数分别是原土的79.5和289倍、106和334倍、418和578倍吸附机理较复杂,主要以分配为主.     

阳离子表面活性剂聚集行为的热力学研究

为了深入了解阳离子表面活性剂溶液在复杂体系中的物理化学性质,以十六烷基三甲基氯化铵(CTAC)和十六烷基三甲基溴化铵(CTAB)为模型,通过电导法和表面张力法研究其在水相体系中的聚集行为。测定两种表面活性剂的临界胶束浓度CMC、胶束离解度β、胶束聚集数n和表面过剩吸附量Γs。由CMC与温度T的关系,应用准相分离模型计算了胶束化热力学参数ΔmicG0、ΔmicH0和ΔmicS0,结果表明ΔmicG0为负值,而且随温度变化很小,ΔmicH0的值相对于TΔmicS0来说小得多,表明胶束化过程为熵驱动过程。     

酵母Candida krusei对合成染料的脱色

通过筛选实验,从土壤中新分离到1株对活性艳红K-2BP具有明显脱色效果的酵母菌株Y-G-I,经鉴定为克鲁斯假丝酵母Candida krusei．该菌株对含活性艳红K-2BP起始浓度为200mg／L的培养基,最大脱色率为99％,达到最大脱色率的时间是12h．克鲁斯假丝酵母的最佳接种量应不低于5％（体积分数）,培养基最适pH在4～9之间,氮源（NH4）2S04浓度不低于0．1％,相对应的碳源葡萄糖浓度不低于0．5％．对脱色机理的研究表明,该菌株对活性艳红K-2BP的去除属于降解脱色．此外,该菌株对另外9种染料（50mg／L）的脱色率在62％～96％之间．其中,对偶氮染料弱酸艳红B、活性黑KN-B和活性红M-3BE的脱色率都达到了90％以上,对三苯甲烷染料（酸性媒介漂蓝B）的脱色率达到了93％．表明克鲁斯假丝酵母在染料废水的处理上可能具有较好地应用潜能．