固定化生物活性炭纤维小球处理苯酚废水研究

采用经苯酚驯化后的活性污泥，以活性炭纤维为载体，以聚乙烯醇（PVA）为包埋剂制成固定化生物活性炭纤维小球。通过研究不同因素对苯酚去除率的影响，确定了制备固定化生物活性炭纤维小球的最佳参数：包泥量为1（污泥／PVA溶液），PVA浓度为20％，包炭量为0．04：1（ACF／PVA溶液），交联时间为12h。研究了温度和pH值对苯酚去除效果的影响，结果表明，温度为5～35℃、pH在6～7时对苯酚的去除率可达90％以上，去除效果明显好于活性炭纤维、生物活性炭及生物活性炭纤维。     

养殖水体氨氮去除的固定化微生物技术

应用固定化技术 ,将富集培养的硝化活性污泥制成固定化小球 ,对固定化小球在不同条件下其硝化活性的影响进行了研究 ;同时 ,采用摇瓶试验比较了固定化小球和悬浮硝化活性污泥对养鳖污水氨氮的处理效果。结果表明 ,固定化小球具有明显抗不利因素的能力 ,降解氨氮的效率稳定 ,对养殖污水氨氮的生物处理具有一定的效果。     

采用海藻酸钠固定化微生物技术处理甲醇废水

将海藻酸钠固定化活性污泥制成颗粒小球,以流化床反应器对甲醇废水进行处理.试验结果表明:在溶解氧为6.6～6.9 mg/L的条件下,固定化小球与废水的体积比为30:1 000,温度为30-40 oC,pH值为5.0～9.0是最佳的工况.在此条件下,当进水COD<722.2 mg/L,进水甲醇<307.4 ms/L时,对COD的去除率>85%,对甲醇的去除率可达到90%左右.     

聚乙烯醇作为固定化细胞包埋剂的研究

以聚乙烯醇为包埋剂 ,探索其制备固定化细胞小球的工艺过程 ,着重从小球颗粒的机械强度、传质性能及微生物活性等三个方面来选择其最适宜的包埋条件。最后 ,还对固定化细胞的保存进行了试验研究     

不同载体固定活性污泥原位修复轻度淤积底泥的效能

底泥修复是黑臭水体治理中的重要环节,原位修复操作简便且对河道的破坏小。利用固定化菌剂原位修复实验装置,探究了活性炭、沸石、陶粒3种载体固定活性污泥修复轻度淤积底泥的效能。载体物理特性及载体对微生物的吸附特性实验结果表明,活性炭相对于沸石和陶粒具有更丰富的孔隙结构和更强的活性污泥吸附能力,沸石的吸附能力强于陶粒。不同载体固定活性污泥原位修复轻度淤积底泥实验结果表明,3种载体固定活性污泥均能有效降低底泥中有机质含量,其中活性炭固定活性污泥对底泥中有机质的降解效果最佳,60 d内有机质含量可降低45.2%;3种载体固定活性污泥均能促进底泥中重金属离子转移,其中沸石固定活性污泥对重金属离子的去除效果最佳,60 d内对铜离子、铬离子、铅离子的去除率分别达到了28.8%、27.2%、37.2%;此外,3种载体固定活性污泥均能有效去除上覆水中的COD_Cr、NH₃-N、TN、TP,60 d内COD_Cr去除率基本超过50%,NH₃-N、TN、TP去除率基本超过80%。综合底泥和上覆水处理效果可知,活性炭固定活性污泥的...     

海藻酸钠添加硅藻精土固定化耐低温硝化细菌

运用海藻酸钠添加硅藻精土的方法,将低温下驯化成熟的硝化污泥制成固定化小球,研究了低温条件下固定化小球对氨氮的去除效果,实验结果表明:海藻酸钠+硅藻精土固定化小球对生活污水的氨氮去除率最终可达到80%左右。     

偶氮染料固定化高效脱色菌厌氧膨胀床脱色研究

偶氮染料固定化高效脱色菌厌氧膨胀床脱色研究①景翔峰（河南省环保所）罗志腾（天津城建学院）林荣忱（天津大学）前言偶氮染料占排放到环境中染料总量的８０％，传统的活性污泥法对很多偶氮染料不能有效去除，物化法高级处理如活性炭吸附费用太高。近年来，通过寻找高效...     

内聚营养源固定化SRB去除硫酸盐和铬的研究

内聚营养源生物固定化技术对于缺乏营养源、存在重金属污染风险的水源地水质安全保障具有独特的意义。以聚乙烯醇和海藻酸钠为交联剂,制备内聚蔗糖、葡萄糖、正丙醇、乙酸钠为营养源的固定化硫酸盐还原菌(SRB)小球。在Cr~(6+)初始浓度为100 mg/L、SO_4~(2-)初始浓度为200mg/L的条件下,探讨不同内聚营养源对固定化SRB小球去除Cr~(6+)和SO_4~(2-)效果的影响。结果表明:内聚蔗糖、葡萄糖、正丙醇、乙酸钠的固定化硫酸盐还原菌能得到较好的Cr~(6+)和SO_4~(2-)去除效果,对Cr~(6+)的最大去除量分别达到333.74、297.14、289和260.54μg/g,对SO_4~(2-)的最大去除量分别达到1 553.60、1 375.64、1 374.46和1 267μg/g。固定化小球去除Cr~(6+)和SO_4~(2-)的最适营养源为蔗糖,其对Cr~(6+)和SO_4~(2-)的最高去除率分别达到99.89%和98.65%。小球内羟基化合物、碳酸氢根离子和硫酸盐成分及其反应效果影响了内聚营养源包埋小球对Cr~(6+)和SO_4~(2-)的去除。     

固定化微生物技术处理含酚废水

采用经苯酚驯化后的活性污泥制成固定化微生物小球，处理了两种不同类型的含酚废水：对于苯酚浓度为2148．0mg/L、COD为10828．8mg/L的高浓度合酚废水，经24h处理后，对苯酚及COD去除率分别为50．1％和38．7％；对于苯酚浓度为180．7mg/L、COD为947mg/L左右的一般浓度混合合酚废水，经6h处理后对苯酚及比COD去除率分别为89．1％和84．6％，而活性污泥法分别为76．6％和75．0％。固定化微生物法的比COD去除率在废水比COD＜1500mg/L时保持稳定，而活性污泥法在比COD＜l000mg／L时保持稳定。固定化微生物法在处理时间及浓度两方面均优于活性污泥法。     

固定化尖镰孢菌去除水中蒽的试验研究

采用聚乙烯醇（PVA）-累托石复合载体包埋固定蒽高效降解菌（尖镰孢菌），用于去除水中的蒽，考察了pH值、蒽初始浓度、固定化尖镰孢菌用量及双氧水浓度对固定化尖镰孢菌除蒽效果的影响。结果表明，当蒽的初始浓度为40mg／L时，在pH值为7～8、固定化尖镰孢菌小球用量为8％～10％、双氧水浓度为20～50mg／L的条件下，可取得较好的去除效果。与未包埋尖镰孢菌的小球相比，固定化尖镰孢菌小球对水中的蒽有较强的去除能力，二次使用时，固定化尖镰孢菌小球对水中的蒽仍具有较好的去除效果。     

关键组分对高聚物乳液基酚醛树脂粉玻化微珠复合保温浆料性能的影响研究

通过试验考察了乳液种类及用量、玻化微珠的级配和用量、酚醛树脂粉的用量、疏水剂的种类和用量对高聚物乳液基酚醛树脂粉玻化微珠复合保温浆料的抗压强度、压剪黏结强度、软化系数、热导率、吸水率等主要性能的影响规律,确定了高聚物乳液基酚醛树脂粉玻化微珠复合保温浆料的最优配方。本产品克服了常用有机、无机保温材料的缺点,具有燃烧性能好、热导率低、吸水率低、生产工艺和施工工艺简单、造价成本低等优点。     

Biocalalyst effects of immobilized anthraquinone on the anaerobic reduction of azo dyes by the salt-tolerant bacteria

The accelerating effect of dissolved redox mediators has been studied in details in the bio-decolorization processes, but there are little literatures about the non-dissolved redox mediators. Here we describe the accelerating effect of anthraquinone as a redox mediator in the bio-decolorization. Decolorization of azo dyes was carried out experimentally using the salt-tolerant bacteria under immobilized anthraquinone and high salt conditions. Anthraquinone as a redox mediator was able to increase the decolorization rate of azo dyes, and was immobilized by entrapment in calcium alginate (CA), Polyvinyl alcohol (PVA)-H(3)BO(3) and agar, respectively. The effects of various operating conditions such as anthraquinone bead number, dissolved oxygen, temperature and pH on microbial decolorization were investigated experimentally. The reusability of the anthraquinone immobilization beads was evaluated with repeated-batch decolorization experiments. After four repeated experiments, the decolorization rate of CA immobilized anthraquinone retained over 90% of their original value. The experiments explored a great improvement of the redox mediator application and the new bio-treatment concept.     

Adsorption and desorption characteristics of mercury(II) ions using aminated chitosan bead

Adsorption and desorption characteristics for mercury ions using aminated chitosan bead which showed very high affinity to mercury ions were studied. The adsorption of mercury ions using aminated chitosan bead was an exothermic process since binding strength each other increased as the temperature decreased. And the adsorption of mercury ions was almost completed in 100 min at 150 rpm. In case that adsorbent dose increased, mercury uptake capacity decreased, while, removal efficiency increased. The beads were not greatly affected by the ionic strength, organic material and alkaline-earth metal ions. Mercury ions adsorbed on aminated chitosan bead were desorbed effectively about 95% by EDTA and the adsorption capacity of the recycled beads can still be maintained at 90% level at the 5th cycle.     

Removal of lead ions from industrial waste water by different types of natural materials

The adsorption capacity of some natural materials for lead such as animal bone powder, active carbon, Nile rose plant powder, commercial carbon and ceramics was studied. The V/m ratio has been chosen to be 500 ml/g. The adsorption process was affected by various parameters such as contact time, pH and concentration of lead solution. The lead uptake percent reaches equilibrium state after 15, 30, 45 and 120 min for bone powder, active carbon, plant powder and commercial carbon, respectively. The uptake percent of lead increased by increasing pH value. The sequence of lead uptake percent (% adsorption) at constant pH from certain concentration of lead nitrate solution by the different natural materials is in the order: bone powder > active carbon > plant powder > commercial carbon. The uptake percent of lead is increased by decreasing the concentration of lead at constant pH. The capacity of lead adsorbed from nitrate solution by the different natural materials increased by increasing pH value. The synthetic and industrial waste-water samples were treated by using the different natural materials (contact time 3h, pH = 4). The percent removal of lead was 100% by bone powder, 90% by active carbon, 80% by plant powder and 50% by commercial carbon. There was no removal of lead by ceramics. This may be due to the presence of high percent of lead in the constituent of ceramics (372 mg/g).     

Uptake of mercury by thiol-grafted chitosan gel beads

This study describes the synthesis and characterization of thiol-grafted chitosan beads for use as mercury (Hg) adsorbents. Chitosan flakes were dissolved and formed into spherical beads using a phase inversion technique, then crosslinked to improve their porosity and chemical stability. Cysteine was grafted onto the beads in order to improve the adsorption affinity of Hg to the beads. The beads possessed an average diameter of 3.2 mm, porosity of 0.9, specific surface area of approximately 100 m2/g, average pore size of approximately 120 angstroms, and specific gravity of 2.0. Equilibrium and kinetic uptake experiments were conducted to study the uptake of Hg by the beads. The adsorption capacity was approximately 8.0 mmol-Hg/g-dry beads at pH 7, and decreased with decreasing pH. Hg adsorption kinetics was modeled as radial pore diffusion into a spherical bead with nonlinear adsorption. Use of the nonlinear Freundlich isotherm in the diffusion equation allowed modeling of the uptake kinetics with a single tortuosity factor of 1.5 +/- 0.3 as the fitting parameter for all initial Hg concentrations, chitosan loadings, and agitation rates. At agitation rates of 50 and 75 rpm, where uptake rate was reduced significantly due to the boundary layer effect, the mass transfer coefficient at the outside boundary was also used as a fitting parameter to model the kinetic data. At agitation rates higher than 150 rpm, pore diffusion was the rate-limiting step. The beads exhibited a high initial uptake rate followed by a slower uptake rate suggesting pore diffusion as the rate-determining step especially at high agitation rates. Higher uptake rates observed in this study compared to those in a previous study of chitosan-based crab shells indicate that dissolution and gel formation increase the porosity and pore accessibility of chitosan.     

The buckling characteristics of some integrally formed bead stiffened composite panels

Composite panel stability can easily be improved by using vertical male beads. In this paper, new methods of stabilizing techniques used for the panels, webs and ribs of composite structures are studied. A parametric study is performed to assess the effects of important design considerations such as, bead length, number of beads, bead radius, bead depth and bead spacing on the initial buckling load of the panels. The results show that, there is an optimum bead spacing for each panel containing more than one bead which can be estimated using a simple equation. Integration of vertical beads with a length of less than 0.5 times the panel's length has no significant effect on the buckling load. There are no significant changes on the buckling loads of the beaded panels with bead depths greater than 0.6 times the bead radius. In this investigation, the instability of the nose and main ribs of a light airplane wing structure made of woven E-glass material and stiffened by P.V.C foam core and vertical male beads are also studied using experimental methods. The experimental results show that we can easily improve the buckling capability of the panels and webs by using vertical male beads instead of sandwiched construction. It is estimated that this would cause a weight reduction of about 50% and a manufacturing time reduction of about 50%.     

Chemisorption of oxygen onto activated carbon can enhance the stability of biological perchlorate reduction in fixed bed biofilm reactors

Fixed bed biofilm reactors with granular activated carbon (GAC) or glass beads as support media were used to evaluate the influence of short-term (12h) and long-term (23 days) increases of influent dissolved oxygen (DO) concentrations on biological perchlorate removal. The goal was to evaluate the extent by which chemisorption of oxygen to GAC can enhance the stability of biological perchlorate reduction. Baseline influent concentrations were 50 microg/L of perchlorate, 2 mg/L of acetate as C, and 1mg/L of DO. Perchlorate removal in the glass bead reactor seized immediately after increasing influent DO concentrations from 1 to 4 mg/L since glass beads have no sorptive capacity. In the biologically active carbon (BAC) reactor, chemisorption of oxygen to GAC removed a substantial fraction of the influent DO, and perchlorate removal was maintained during short-term increases of influent DO levels up to 8 mg/L. During long-term exposure to influent DO concentrations of 8.5mg/L, effluent perchlorate and DO concentrations increased slowly. Subsequent exposure of the BAC reactor bed to low DO concentrations partially regenerated the capacity for oxygen chemisorption. Microbial analyses indicated similar microbial communities in both reactors, which confirmed that the differences in reactor performance during dynamic loading conditions could be attributed to the sorptive properties of GAC. Using a sorptive biofilm support medium can enhance biological perchlorate removal under dynamic loading conditions.     

Photodynamic inactivation of E. coli by immobilized or coated dyes on insoluble supports

The photodynamic inactivation of E. coli by methylene blue, rose bengal and eosin covalently immobilized on polystyrene beads and that of methylene blue coated on granular activated carbon, silica gel and XAD-2 (polystyrene resin) was studied. For the study light-exposed and aerated tap-water contaminated with E. coli subjected to dye sensitized photo-oxidation was used. After 0, 10, 20, 30, 40 and 60 min treatment time, samples were diluted and plated on agar to determine the number of Colony Forming Units (CFU). The study gave the following results: all the light exposed and aerated immobilized dyes (methylene blue, rose bengal and eosin) had an elevated photodynamic action on E. coli. After only 30 min treatment time there was 97.5% inactivation of E. coli by methylene blue, 92.2% by rose bengal and 81.6% by eosin. Methylene blue proved to be the most active. Methylene blue coated on activated carbon, silica gel and XAD-2 also had a high photodynamic action. Activated carbon was found to be the best support; since after 30 min contact it had adsorbed 2 mg g⁻¹ of dye and inactivated 94.4% of E. coli. Comparing the differences in the regression lines of the various methods employed (parallel test) it was found that the effect of each dye was significantly high (P = 0.001) whereas there was no significant difference between methylene blue immobilized and coated on active carbon. From these results it seems that sensitized photo-oxidation using methylene blue coated on activated carbon can be used as an alternative for disinfecting waters for potable purposes, but its effectiveness against other micro-organism present in the water must also be tested.     

Chemical modification of chitosan and equilibrium study for mercury ion removal

To increase the uptake capacity of mercury ions, several chemical modifications of chitosan beads which are cross-linked with glutaraldehyde were performed. Among them, aminated chitosan bead prepared through chemical reaction with ethylenediamine had a high uptake capacity of about 2.3 mmol g(-1) dry mass at pH 7. The increased number of amine groups was confirmed by IR analysis and measuring the saturation capacities for adsorption of HCl. The surface condition and existence of mercury ions on the beads was confirmed by the environmental scanning electron microscope and energy dispersive X-ray spectroscopy instrumental analyses. The beads showed the characteristic of competitive sorption between mercury and hydrogen ions and it was successfully modelled by an equilibrium model.     

Mechanisms of lead biosorption on cellulose/chitin beads

Environment-friendly cellulose/chitin beads being prepared by coagulating a blend of cellulose and chitin in 6 wt% NaOH/5 wt% thiourea aqueous solution with 5% H2SO4 possessed higher heavy metals uptake capacity than pure chitin flakes. The mechanisms of Pb2+ adsorption on cellulose/chitin beads at pH0=5 were investigated at the molecular levels by scanning electron micrographs (SEM), transmission electron micrographs (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD). The result revealed that mechanisms for the adsorption of Pb2+ on the cellulose/chitin beads could be described as complexation between Pb2+ and N atom in the chitin, and further adsorption of Pb2+ nearby the complexed Pb2+ and precipitation of the hydrolysis product of the Pb2+ complex on the beads as the crystalline state. Furthermore, structural factors such as larger surface area of the beads resulted from microporous-network structure, low crystallinity of cellulose/chitin beads and high hydrophilicity induced by hydrophilic skeleton of cellulose played an important role in increasing adsorption ability.