生物膜处理高含油废水及膜表面微生物群落特性研究

利用单一铜绿假单胞菌NY3生物膜在敞开体系中（非无菌条件下）处理石油废水,结果发现,生物膜可高效率去除高浓度含油废水中的油类物质.在2g/L含油水样中,连续运行25d,石油烃去除率可持续保持约91.1%.停止进水后,曝气可使生物膜活性恢复.自然环境中,配伍于NY3菌生物膜中的微生物主要有芽孢杆菌、假单胞菌和红球菌属,其中在实验室能够培养出来的微生物经16SrRNA鉴定分别属于红球菌属和芽孢杆菌属,经检测,2株菌均有高的石油烃降解效率.     

Optimization of mixture ratio of electrolyte for reducing activation resistance of proton exchange membrane fuel cell

The purpose of this study is to find an optimal mixture ratio of the platinum-loaded carbon catalyst and the electrolyte in a membrane electrode assembly (MEA) of a proton exchange membrane fuel cell for reducing the activation resistance, which influences the electrochemical surface area, activation polarization, and maximum power density of the MEA. First, mixture ratios of 10, 20, 40, and 60 wt% platinum-loaded carbon catalysts and electrolyte were examined. The results indicated that the fuel cell performance improved for mixing weight ratios of 1.0:2.0 in 10 wt% Pt/C, 1.0:1.8 in 20 wt% Pt/C, 1.0:1.1 in 40 wt% Pt/C, and 1.0:0.5 in 60 wt% Pt/C. Next, we evaluated the activation resistances of the MEA from the AC impedance characteristics using the optimal mixing weight ratio of the platinum-loaded carbon catalyst and the electrolyte. It was found that the activation resistances of the anode and cathode decrease with an increase in the weight ratio of platinum-loaded carbon in the catalyst layer.     

深孔预裂爆破在深井高瓦斯低透气性煤层瓦斯抽采中的应用

为解决潘一东矿深井低透气性高瓦斯煤层瓦斯抽采率低的问题,提出了运用深孔预裂爆破技术提高煤层透气性,进行瓦斯预抽,进而提高瓦斯抽采率,降低煤层突出危险性的方法。通过数值模拟阐述了深孔预裂爆破技术的作用机理,并对潘一东矿应用效果进行了现场考察。研究表明:在低透气性煤层实施深孔预裂爆破技术后,煤层透气性得以提高,平均瓦斯抽采量提高了3倍,有效地提高了瓦斯抽采率,降低了煤体瓦斯压力和含量,从而在一定程度上降低了煤与瓦斯突出的危险性。     

臭氧/陶瓷膜对生物活性炭工艺性能和微生物群落结构影响

利用处理量为120m3/d的臭氧/陶瓷膜-生物活性炭(BAC)组合工艺处理微污染原水, 对工艺性能和BAC中的微生物多样性和种群结构进行了研究.结果显示,组合工艺可有效去除微污染原水中的有机物和氨氮.臭氧曝气提高了溶解氧浓度,改善了后续BAC工艺对氨氮的去除效果.组合工艺对氨氮和CODMn的总去除率分别约为90%和84%,其中BAC在污染物的去除中发挥了重要作用.组合工艺和传统工艺中BAC床层共检测到36个门类的细菌.与传统BAC工艺相比,臭氧/陶瓷膜降低了后续BAC中微生物群落结构的多样性和均匀度.组合工艺BAC中存在丰度较高的亚硝化单胞菌属和硝化螺旋菌属,可能对氨氮的去除具有重要的作用.臭氧/陶瓷膜对后续BAC中致病菌和条件致病菌有很好的预处理和抑制作用,显著降低了其相对丰度,提高了饮用水的生物安全性.     

盐度对膜-生物反应器污泥表观硝化速率的抑制机理

为研究盐度对膜-生物反应器(MBR)污泥表观硝化速率的抑制机理,采用批次试验模拟不同盐度条件下MBR活性污泥的硝化反应并测定其表观硝化速率、自养菌活性和SMP、EPS中脱氧核糖核酸和蛋白质的含量变化.结果表明,随着盐度的不断提高,污泥表观硝化速率逐渐下降,当盐度大于12.5g/L时,污泥体系出现NH4+-N含量上升的现象.自养菌的活性逐渐被抑制,抑制程度和盐度正相关,当盐度大于2.5g/L时,SMP和EPS中DNA的含量逐步上升,细胞结构被破坏是微生物活性被抑制的原因.SMP和EPS中蛋白质含量随着盐度的提升明显增长,蛋白质在污泥系统水解并发生氨化释放NH4+-N也是表观硝化速率下降的原因;当盐度小于12.5g/L,系统释放NH4+-N对表观硝化速率抑制作用随着盐度的提高而不断提升.     

Effect of protein on PVDF ultrafiltration membrane fouling behavior under different pH conditions: interface adhesion force and XDLVO theory analysis

To further determine the fouling behavior of bovine serum albumin (BSA) on different hydrophilic PVDF ultrafiltration (UF) membranes over a range of pH values, self-made atomic force microscopy (AFM) colloidal probes were used to detect the adhesion forces of membrane–BSA and BSA–BSA, respectively. Results showed that the membrane–BSA adhesion interaction was stronger than the BSA–BSA adhesion interaction, and the adhesion force between BSA–BSA-fouled PVDF/PVA membranes was similar to that between BSA–BSA-fouled PVDF/PVP membranes, which indicated that the fouling was mainly caused by the adhesion interaction between membrane and BSA. At the same pH condition, the PVDF/PVA membrane–BSA adhesion force was smaller than that of PVDF/ PVP membrane–BSA, which illustrated that the more hydrophilic the membrane was, the better antifouling ability it had. The extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) theory predicts that the polar or Lewis acid–base (AB) interaction played a dominant role in the interfacial free energy of membrane–BSA and BSA–BSA that can be affected by pH. For the same membrane, the pH values of a BSA solution can have a significant impact on the process of membrane fouling by changing the AB component of free energy.

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Behavior of aqueous stable colloidal nano-C60 aggregates exposed to TX100 micelles under different environmental conditions

C₆₀, as one of carbon nanomaterials widely used in various fields, could be released into the water environment thus exerting some potential health risks to human beings. This work examined the behavior of aqueous stable colloidal nano-C₆₀ (nC₆₀) aggregates under different environmental conditions including Polyethylene glycol octylphenol ether (TX100) micelles concentration, pH, and reaction time when exposed to TX100 micelles. Results show that the nC₆₀ aggregates became more dispersive and restored the capability of generating the singlet oxygen when exposed to TX100 micelles. With the increase of TX100 concentration, smaller average size of nC₆₀ aggregates was observed in dynamic light scattering (DLS) analysis, the fluorescence intensity of TX100 was more quenched by nC₆₀ aggregates, and the kinetic rate constant of generating the singlet oxygen for nC₆₀ aggregates was improved. The mean size of nC₆₀ aggregates in the presence of TX100 had no obvious variations when the pH ranged from 4 to 8. The longer reaction time between nC₆₀ aggregates and TX100 led to a higher kinetic rate constant of generating the singlet oxygen. Collective data suggest that variations in physicochemical properties of nC₆₀ aggregates are strongly dependent on the surrounding media under different environmental conditions and directly govern nC₆₀’s transport behavior and potential toxicity.     

LDPE膜被动采样技术预测模型的建立及其应用

选用3种厚度的低密度聚乙烯(LDPE)膜(76,56和25μm)作为研究对象,对辛醇-水分配系数的对数(logKow)>2的有机污染物采用被动采样技术进行膜-水分配系数(Kpew)实测实验和动力学实验,首次建立考虑时间(t),膜厚度(d)和动力学3个因素的LDPE膜 Kpew预测模型.实验结果表明,预测模型得到的Kpew与实测Kpew的相对误差为±0.03,证明了预测模型的准确性和可靠性.Kpew预测模型的建立避免了实验监测Kpew的繁琐实验过程,从而极大地提高了有机污染物的监测效率.将预测模型Kpew值应用于浑河与东洲河有机污染物质的监测,监测结果进一步表明了预测模型的准确性和实用性.此外本文首次提出了苯系物的Kpew值,对LDPE膜被动采样技术应用的延伸属于突破性进展.     

蔗糖改性纳米铁原位反应带对硝基苯污染的模拟修复研究

在一维模拟装置中创建改性纳米铁原位反应带,研究反应带对硝基苯污染的修复情况,并通过反应带渗透性变化对其可持续修复能力进行评估.模拟试验结果表明:不同条件下硝基苯的去除率为45%~80%;反应带渗透性变化过程按时间分为3个阶段,分别是0~10d的快速下降期、10~30d的缓慢下降期和30~60d的稳定期,平均下降了53.2%,堵塞现象未发生,反应带可持续修复能力较好.较大的介质粒径和浆液浓度使污染物降解效率增加,硝基苯去除率可分别提高23.7%和13.7%;较高的地下水流速和污染物浓度不利于污染物的去除,硝基苯去除率均下降约46.8%.各反应带中实际参与反应的铁与硝基苯的物质的量比值分别为11.2、17.9、12.6、3.3和25.7,改性纳米铁颗粒的实际利用率较低,实际应用中浆液需要过量注入.     

深部开采松软煤层抽采钻孔变形特性研究

为了研究深部开采松软煤层抽采钻孔变形失稳特性,基于有限元理论和统计损伤理论数值模拟了深部开采松软煤层抽采钻孔变形失稳整个过程,分析了钻孔周围煤体应力及形变分布、卸压区演化和渗透特性。研究表明:钻孔破坏形式为上方发生垮塌,形成垮塌区;左右侧发生破坏,形成破碎区;钻孔周围煤体均向钻孔移动,钻孔附近煤体位移量较大,远处煤体位移量相对较小;钻孔形状由开始的圆形逐渐变成“类橄榄球形”,然后钻孔“类橄榄球形”断面逐渐减小至坍塌。钻孔失稳过程中,钻孔附近煤体渗透率逐渐增大,钻孔周围煤体渗透率变化量及变化范围均不断增加;周围煤体渗透率分布均大致呈“V”字型变化规律,即煤体渗透率呈随着距钻孔距离的增加先减小后增加然后趋于稳定的趋势。研究结果可以为我国煤矿深部开采松软煤层瓦斯治理和煤层瓦斯抽采提供理论支撑,具有指导性意义。