考虑损伤与剪胀及中间主应力的巷道围岩弹塑性分析

为研究圆形巷道围岩的稳定性,考虑了巷道围岩的损伤、剪胀特性以及中间主应力效应,建立了圆形巷道围岩弹塑性损伤力学模型,推导出圆形巷道围岩的弹塑性应力场和位移场解析解。研究结果表明:考虑损伤时围岩塑性区范围更大,所需支护阻力增长明显,塑性区位移明显增加;剪胀对位移场影响较大,对应力场影响较小,剪胀系数越大,需要提供的支护阻力就越大;随着中间主应力系数的增大,所需支护阻力降低,塑性区位移减小,最大位移减小幅度高达79.74%,不考虑中间主应力的强度准则偏于保守;考虑损伤、剪胀和中间主应力的新的位移解更加合理,研究成果为圆形巷道的设计支护提供了一定的理论基础和参考价值。     

海藻酸钠固定化纳米铁还原脱色活性红X3B

采用海藻酸钠固定纳米铁制备海藻酸钠纳米铁小球,研究了海藻酸钠浓度、纳米铁含量、活性红X3B浓度、反应温度、pH值等对海藻酸钠固定化纳米铁小球还原活性红X3B的影响.采用高效液相色谱（HPLC）、紫外可见分光光度计（UV-Vis）、扫描电镜（SEM）、透射电镜（TEM）等方法分析污染物的还原脱色过程.结果表明,X3B的还原脱色获得了较好的效果,当温度25.0℃,海藻酸钠浓度2.0%,纳米铁含量2.0g/L,转速200r/min,pH值10.9时,反应720min后,25.0mg/L活性红X3B的脱色率达98.9%.海藻酸钠凝胶对活性红X3B没有吸附作用,海藻酸钠固定化纳米铁小球降解活性红X3B的主要机制为纳米零价铁的还原作用.     

Modeling of adsorption isotherms and kinetics of uranium sorption by magnetic ion imprinted polymers

Application of magnetic U(VI) ion imprinted polymers (IIPs) coated on magnetic nanoparticles was investigated for pre-concentration and determination of U(VI) ions in aqueous solutions. The scanning electron micrographs revealed the microporosity of the adsorbent. Uranium leaching was successful as the energy-dispersive X-ray spectra showed. The Brunauer–Emmett–Teller (BET) surface area improved by more than 13-fold (83.1 and 6.2 m² g^?1 for the leached and unleached magnetic IIP, respectively). U(VI) uptake was optimized using batch experiments with parameters affecting the uptake performance, such as initial uranium concentration, pH, contact time, and adsorbent dose investigated. Pseudo-second-order kinetics and the Langmuir isotherm model best fitted the experimental data. The maximum adsorption capacity of uranium onto the activated magnetic IIP reached 5.4 mg g^?1. The selectivity order was determined to be U(VI) > Ni(II) > Th(IV).     

Removal of Janus Green dye from aqueous solutions using oxidized multi-walled carbon nanotubes

Multi-walled carbon nanotubes (MWCNTs) were oxidized and characterized by Fourier transform infrared spectroscopy. The adsorption characteristics of the oxidized MWCNT adsorbent were examined using Janus Green (JG) as adsorbate. In batch tests, the effects of pH, adsorbent dose, contact time, and temperature were studied. The maximum adsorption capacity was found to be 56 mg g^?1. The experimental data were fitted to the Langmuir, Freundlich, and Tempkin isotherm models, the first one being the most appropriate. Kinetic analysis showed that adsorption was most accurately represented by a pseudo-second-order model.     

Identification of Sudan III-(deoxy)-guanosine adducts formed in situ in a reaction with no catalyst

Incubation of guanosine and Sudan III induces the formation of a stable adduct, which may be identified using a spectrophotometric technique and mass spectroscopy. The high nucleophilicity of the C⁸ position and its proximity to N⁷ makes the site susceptible to a nucleophilic attack, which explains the S_N2 reaction detected between guanosine and Sudan III dye. In addition, direct interaction of Sudan III with calf thymus DNA was monitored using a simple spectrophotometric technique. The results presented indicate that a simple modification of the chemical structure of Sudan I (monoazo dye) to Sudan III (diazo dye) markedly alters reactivity towards nitrogenous DNA bases.     

Adsorption of methylene blue from aqueous solution by chemically treated water hyacinth

Water hyacinth (WH), an aquatic plant macrophyte, was investigated for its ability to perform as a suitable adsorbent for methylene blue (MB) from aqueous solution. The non-living biomass of WH was subjected to several chemical treatments, namely, washing with hot water, washing with hot dilute HCl, soaking in NaOH, soaking in HNO₃, and sulfonation. The system variables studied also include pH and MB concentration. The Langmuir isotherm was found to represent the measured adsorption data well except for WH soaked in NaOH, which was found to be better represented by the Freundlich isotherm. Values of the dimensionless separation factor, K _R, indicated that the adsorption systems in this study are all favorable. Values of the first layer of adsorption were calculated by the non-linear multilayer adsorption model, and the specific surface area values were found to be high and comparable to commercially activated carbons.     

微电解-H/O-生物接触氧化工艺处理染料废水

某染料厂采用微电解-H/O-生物接触氧化组合工艺处理染料废水。工程设计规模为高浓度有机废水30 m3/d、低浓度有机废水70 m3/d,运行结果表明,该工艺处理效果良好,出水ρ(COD)≤100 mg/L,ρ(苯胺)≤1 mg/L,色度≤50倍,ρ(氨氮)≤15 mg/L,pH为6～9,达GB 8978—1996《污水综合排放标准》一级标准。     

电解-厌氧-好氧-气浮工艺处理分散染料废水

介绍了采用电解-厌氧-好氧-气浮组合工艺对难生化降解的分散染料废水进行高低浓度分治处理的工程实例。工程运行结果表明:实行高低浓度废水的分治处理能有效提高整体系统的处理效率;电解预处理工艺不但能去除高浓度母液废水中75%～90%的色度和25%～40%的COD,还可提高母液废水的可生化性;混合废水再通过厌氧-好氧-气浮处理后,各项水质指标均达GB 8978—1996《污水综合排放标准》中的二级排放要求。     

东方伊萨酵母YP-1对染料活性艳红K-2BP的脱色

利用含染料的选择性培养基从土壤中分离出一株对活性艳红K-2BP有明显脱色效果的酵母菌株YP-1,经鉴定为东方伊萨酵母Issatchenkia orientalis.结果表明,该酵母菌对￡400mg/L的活性艳红K-2BP有较好的脱色效果.对于活性艳红K-2BP起始浓度为100mg/L的培养基,该菌株可在12h达到99%以上的最大脱色率,其最佳接种量为10%(体积分数),最适pH值在3~9之间,氮源(NH4)2SO4的浓度30.02%,碳源葡萄糖的浓度30.2%.脱色机理研究结果表明,该酵母对活性艳红K-2BP的去除是先吸附后生物降解.此外,该菌株对初始浓度为200mg/L的偶氮染料活性黑KN-B的脱色率也可达99.5%.     

A new efficient azo dye-decolorizing bacterium Paenibacillus dendritiformis GGJ7 and its decolorization process北大核心CSCD

This paper aimed to find an efficient bacterium for decolorizing azo dyes. A strain which could decolorize Congo Red efficiently was isolated from Congo Red. The strain was identified as Paenibacillus dendritiformis GGJ7 (GGJ7, in short) by 16S rRNA gene sequence (NCBI accession No. KY655213). Strain GGJ7 was applied to the decolorization of azo dyes in this research, and influencing factors of decolorization were investigated, including diverse nutritional conditions, culture conditions (pH, temperature, oxygen conditions), and various dyes. The results demonstrated that the decolorization rate of Congo Red by strain GGJ7 was much higher than that of the other eight strains (e.g., YRJ1, YRJ2 etc.) in our previous work. The optimal conditions for Congo Red decolorization were 25 g/L LB broth as nutrient source, 30 °C, pH 7, and an anaerobic environment. The mechanism of decolorization was mainly biodegradation, and the decolorization process of strain GGJ7 was conformed to the first-class kinetics model: -ln (At /A0) = 0.6058t - 0.1082. For different azo dyes, the decolorization rate was up to 95%. Strain GGJ7 only needed 1 h to decolorize 50 mg/L Methyl Orange, 25 mg/L Croceine Scarlet, and 25 mg/L Methyl Red, needed 3 h to decolorize 50 mg/L Orange G and 50 mg/L Orange G6, and needed 4 h to decolorize 50 mg/L Congo Red. In summary, strain GGJ7 is an efficient azo dye-decolorizing bacterium, and it has a potential application in treating printing and dyeing wastewater. © 2018 Science Press. All rights reserved.