水生腐殖酸分子量分布研究——Ⅰ.串联凝胶色谱法测定水生腐殖酸分子量分布

考察了测定水生腐殖酸分子量分布及其平均分子量的串联凝胶色谱法。结果表明,使用Sepbadex G-25和G-100两种凝胶的色谱柱系统的分离范围可从分子量1000左右到数万,几乎包括了水生腐殖酸分子量分布的整个区段。这样的串联凝胶色谱柱的标定曲线为一折线,可用分段函数近似地加以描述。     

制备条件对硅胶负载氧化锆吸附除氟的影响

应用浸渍法制备了硅胶负载氧化锆除氟吸附剂,研究了焙烧温度、硅胶粒度、浸渍时间、浸渍温度、浸渍液浓度、浸渍固液比和浸渍次数等制备参数对吸附剂吸附容量的影响.实验发现焙烧温度有较大影响,450℃焙烧有最大的吸附量,再升高温度吸附量迅速下降.浸渍可在2h内达到平衡.浸渍温度越高,浸渍液浓度越高,则吸附容量越大.采用较高浓度一次浸渍优于低浓度多次浸渍.硅胶粒度和浸渍固液比也影响吸附量,粒度越大吸附量越小,粒度小于0.25mm后吸附量趋于稳定.     

铜暴露下赤子爱胜蚓（Eisenia foetida）活体基因的损伤研究

通过碱性单细胞凝胶电泳法研究了Cu2+暴露剂量对赤子爱胜蚓(Eiseniafoetida)活体基因损伤的动态影响.结果显示:不添加Cu2+的对照组和添加Cu2+的处理组蚯蚓体腔细胞尾部DNA含量和尾长均呈非正态分布(p<0.05);在暴露72h时,125mg·L-1Cu2+处理组尾部DNA含量值最大,为41.44%,100mg·L-1Cu2+处理组尾长值最大,为33.79μm;随着Cu2+暴露剂量的增加,尾部DNA含量和尾长损伤频率增加;对照组和处理组的尾部DNA含量和尾长之间均存在显著性差异(p<0.05),Spearman非参数相关分析表明,尾部DNA百分含量和尾长之间呈显著相关(p<0.01,n=21),Cu2+暴露浓度与尾部DNA百分含量、尾长具有良好的剂量-构效关系(p<0.01).在125mg·L-1Cu2+浓度下暴露72h时蚯蚓的基因损伤程度达到最大,损伤程度为3级.可见,蚯蚓DNA生物标志物是重金属污染基因毒理诊断的重要指标,碱性SCGE试验是检测Cu2+暴露对赤子爱胜蚓活体基因损伤的有效手段.     

Mechanism on minimization of excess sludge in oxic-settlinganaerobic (OSA) process

The oxic-settling-anaerobic (OSA) process is a promising wastewater treatment technique for efficiently reducing sludge production and improving the stability of process operation. In this paper, the possible factors of sludge reduction such as sludge decay, uncoupled metabolism, and anaerobic oxidation with low sludge production were discussed in the OSA process. It has been confirmed that sludge decay is the decisive cause in the OSA process, accounting for 66.7% of sludge production reduction. Sludge decay includes hydrolysis and acidogenesis of dead microorganisms and particle organic carbon adsorbed in sludge floc and endogenous metabolism. By batch experiments, it has been proven that there is energetic uncoupling in the OSA system since microorganisms were exposed to alternative anaerobic and aerobic environment. It accounts for about 7.5% of sludge production reduction. Soluble chemical oxygen demand (SCOD) released from the anaerobic sludge tank in the OSA process was used as the substrate for cryptic growth. The substrate was used for anoxic denitrifying, anaerobic phosphorus release, sulfate reduction, and methane production. These anaerobic reactions in the sludge anaerobic tank have lower sludge production than in the aerobic oxidation when equivalent SCOD is consumed, which may lead to approximately 23% of sludge reduction in the OSA process. It has been concluded that multiple causes resulted in the minimization of excess sludge in the OSA system. The microbial community structure and diversity of sludge samples from the CAS (conventional activated sludge) and OSA systems were investigated by 16 SrDNA PCR-DG-DGGE (polymerase chain reaction-double gradient-denaturing gradient gel electrophoresis). DGGE profile and cluster analysis showed more abundant species in the OSA system contrasting to microbial communities in the CAS system.     

Novel synthesis of aluminum hydroxide gel-coated nano zero-valent iron and studies of its activity in flocculation-enhanced removal of tetracycline

A newly designed aluminum hydroxide gel-coated nanoscale zero-valent iron(AHG@NZVI)with enhanced activity and dispersibility of NZVI was successfully synthesized.The AHG@NZVI composite was synthesized via control of the surface AHG content.AHG@NZVI-1,AHG@NZVI-2 and AHG@NZVI-3 were prepared under centrifugal mixing speeds of 1000,2000 and 4000 r/min,respectively.The activity of AHG@NZVI was evaluated by its tetracycline(TC) removal efficiency.The effects of AHG content,pH value,reaction temperature,and presence of competitive anions on TC removal were investigated.TC could be removed by both adsorption and chemical reduction on AHG@NZVI-2(centrifugal speed 2000 r/min) in a short time with high removal efficiency(≥98.1%) at the optimal conditions.Such excellent performance can be attributed to a synergistic interaction between aluminum hydroxide gel and NZVI:(1) AHG could enhance the stability and dispersity of NZVI;(2) aluminum hydroxide gel could absorb a certain amount of TC and Fe~(2+)/Fe~(3+),which facilitated the mass transfer of TC onto the NZVI surface,resulting in acceleration of the reduction rate of TC by the AHG@NZVI composite;and(3) AHG-Fe~(2+)/Fe~(3+)could absorb a certain amount of TC by flocculation.The kinetics of TC removal by AHG@NZVI composite was found to follow a two-parameter pseudo-first-order model.The presence of competitive anions slightly inhibited the activity of AHG@NZVI systems for TC removal.Overall,this study provides a promising alternative material and environmental pollution management option for antibiotic wastewater treatment.     

兔子宫内膜蛋白等电聚焦电泳载体两性电解质pH范围及比例的选择

兔子宫内膜蛋白是研究早期胚胎发育过程中胚泡附植机制的关键因素之一．为了对子宫内膜蛋白进行有效的分离，本研究探讨了用于等电聚焦电泳的载体两性电解质pH范围及其比例．研究结果表明：在只有pH3～9．5的情况下，蛋白质谱带主要分布于胶条碱性端1／3区域，酸性端无谱带；在载体两性电解质pH3-9．5：pH4～6=1：4的情况下，蛋白质谱带主要分布于胶条碱性端2／3部分；在载体两性电解质以pH3-9．5：pH4～6：pH6—9=1：4：1时，蛋白质谱带分布比较均匀，酸性端也有谱带分布．这说明在作子宫内膜蛋白的等电聚焦电泳时采用pH3～9．5：pH4～6：pH6～9=1：4：1比较理想．     

压裂返排液循环使用技术综述

综述了传统处理方法和深度处理方法两大类压裂返排液处理方法的特点和处理效率。介绍了对氧化破胶的压裂返排液和非氧化破胶的压裂返排液进行处理的方法和机理,以及返排液循环使用效果和性能检测的标准。指出研发含有高分子聚合物稠化剂的返排液循环使用工艺、高效便捷的压裂返排液循环使用工艺和新型可循环使用的压裂液体系等将是未来压裂返排液循环使用的发展方向。     

一种新型泡沫凝胶成胶时间及灭火特性的实验研究

为研究新型无氨泡沫凝胶的胶凝特性和灭火特点,采用倾斜试管法分别测试了不同反应物浓度、温度、pH值和发泡剂浓度等参数对新型泡沫凝胶成胶时间的影响,同时通过灭火实验对泡沫凝胶的消防特性进行了研究。结果显示：当水玻璃与促凝剂的质量比在1．33—4．0时材料成胶时间满足煤矿灭火要求;pH值在6．9—8．5时成胶最快;成胶时间随温度升高而减小;发泡剂浓度对成胶时间影响不大;泡沫凝胶灭火效果良好且有效延长了复燃周期。因此泡沫凝胶在矿井消防中有很强的实用价值,并且可通过限制反应物浓度、pH值、温度等参数,更高效的控制成胶时间。     

过硫酸铵胶囊破胶剂的混储危险性研究

为评价过硫酸铵胶囊破胶剂的混储危险性,测试了过硫酸铵胶囊破胶剂的氧化性,并分别采用压力传感器法和差示扫描量热法测试了非氧化剂过硫酸铵胶囊破胶剂与其他化学品的相容性。试验发现,过硫酸铵胶囊破胶剂由于外壳的包覆作用,其氧化性下降,个别过硫酸铵胶囊破胶剂不属氧化剂;但是通过相容性测试发现,过硫酸铵胶囊破胶剂与多数有机物质不相容。因此在储存过程中应与可燃物质以及还原剂等隔离。     

Competitive sorption and diffusion of chromate and sulphate in a flow system with goethite in gel beads

Column experiments and model simulations were employed to evaluate the processes involved in multicomponent solute transport in a system with heterogeneous flow. Column experiments were performed with goethite embedded in polyacrylamide gel beads. The gel forms an immobile water region that can be accessed by diffusion. A two-region transport model with diffusion into spheres was combined with a surface complexation model to predict reactive transport in the goethite-gel bead system. Chromate and sulphate breakthrough curves were measured in a set of transport experiments, along with corresponding changes in the pH of the effluent. Sorption and transport of sulphate and chromate in separate columns were predicted from independently measured sorption parameters. The model overestimated the pH changes in the effluent, possibly because of proton buffering by the polyacrylamide gel. The effect of competitive sorption on transport was examined in experiments with both anions present. The model predicted the effect of competition very well in a system initially equilibrated with sulphate, followed by infiltration with chromate. However, when sulphate was infiltrated after equilibration with chromate, chromate desorption and sulphate adsorption were clearly overestimated by the transport model. The exchange between the more strongly bound chromate and the sulphate added subsequently may be too slow to cause a substantial chromate peak in the effluent. This suggests that the local equilibrium assumption was not applicable in this case.