聚合物／甘蔗渣复合材料研究进展

甘蔗渣是一种可再生的生物资源,将其与聚合物共混制备木塑复合材料则是当代甘蔗渣高值化利用的发展方向之一。系统地介绍了甘蔗渣的预处理技术、加工温度和甘蔗渣加入量等因素对聚合物／甘蔗渣复合材料性能的影响。在制备复合材料的过程中除了要注重甘蔗渣的加入量和预处理方法外,还要着重选择良好的相容剂和不同的改性方法,才能改善甘蔗渣与聚合物的相容性,充分展现甘蔗渣在木塑复合材料中的优势。     

综合化工废水处理技术的研究进展

阐述了我国综合化工废水的来源和特点。针对目前国内外主要综合化工废水处理技术,如物理化学工艺和生物强化工艺等进行了综述,总结了各种处理技术在综合化工废水处理中的应用实例、研究成果和存在的问题。提出了今后综合化工废水处理的研究方向和发展趋势。     

正火预处理对高速犁用28MnB5钢组织及力学性能的影响

为解决现有国产高速犁入土部件存在强韧性不足的问题,研究了正火-淬火-回火(N-Q-T)工艺对28MnB5钢微观组织与力学性能的影响机制,并与现有淬火-回火(Q-T)工艺生产的高速犁入土部件进行了对比。结果表明,N-Q-T态和Q-T态28MnB5钢的组织均以板条马氏体为主,N-Q-T态的马氏体板条平均宽度(0.9μm)显著低于Q-T态(1.5μm),且N-Q-T态的强度和韧性均显著高于Q-T态。基于Hall-Petch关系进一步分析可知,板条马氏体细化是导致N-Q-T态28MnB5钢强度提升的主要原因。同时,N-Q-T态28MnB5钢的板条马氏体细化也导致其大角度晶界占比(34.9%)显著高于Q-T态(25.1%),有助于产生更多的残留奥氏体来抑制裂纹的扩展,从而间接地提高韧性。     

基于预处理的水样检测结果分析

水样预处理过程中的不同处理方法或者说操作步骤对氨氮分析结果的影响有重要的影响,实验分析水样预处理方法对氨氮分析结果产生的影响,希望本实验的结果和分析能为实验操作人员提供一些有用的数据和经验,给广大实验操作者提供比较明确的数据和结论,以使操作人员能清晰判断要预处理与否并对水样进行合理的预处理操作。     

Effects of iron surface pretreatment on sorption and reduction kinetics of trichloroethylene in a closed batch system

The decline of trichloroethylene (TCE) in a metallic iron-water system results from the combination of reduction reaction and sorption onto iron surfaces. Sorption, particularly by highly impure iron, accelerates the removal of TCE from the aqueous phase, but delays the prevalence of steady-state conditions. In this case, an overly high value of reaction rate constant in the design of a treatment system would be used. In this work, the effects of an iron surface with 8.0% C, 6.1% O and 0.8% Si separately following HCl-washing and H2-reducing pretreatment on sorption and reduction rates were examined. The amounts of both aqueous and sorbed TCE were measured using a modified solvent-extraction method. TCE sorption onto an iron surface, as quantified by the Langmuir sorption maximum, followed the trend H2-reduced Fe0 > HCl-washed Fe0 > untreated Fe0 (0.887, 0.365 and 0.311 mg/g, respectively). Measurements of the concentration of sorbed TCE revealed that about 34-37% of the initial mass of TCE in the aqueous phase was removed by sorption by H2-reduced Fe0, 16-19% was removed by HCl-washed Fe0 and 13-16% was removed by untreated Fe0. A combination of new and previously reported data on cast iron's capacity to sorb TCE revealed a linear relationship between this capacity and the C fraction in the surface of the iron, with the coefficient of determination (r2) exceeding 0.99. The first-order observed rate constants (k(obs)) of the reduction of TCE in contact with Fe0 were obtained from the slope of a plot of total TCE loss rate (-dC(T)/dt) versus the amount of TCE in the aqueous phase (C(w)) using linear least-squares analysis. The k(obs) values were 0.080, 0.148 and 0.191 h(-1) for untreated, HCl-washed and H2-reduced Fe0, respectively. Normalized to iron surface area concentration, the specific rate constants (k(SA)) were 2.3 7x 10(-3) , 2.31 x 10(-3) and 5.62 x 10(-3) h(-1) m(-2) L, respectively. The results indicated that HCl-washing approximately doubled k(obs), primarily because of the increase in the surface area of the iron, and it slightly decreased k(SA) due to rapid corrosion during the rinsing process. Both the number of reactive sites and the sorption capacity per unit iron surface area through the H2-reducing pretreatment were increased due to the reduction of iron oxide layer and the carbonization of carbon-containing subjects on the iron's surface. Hence, the H2 reduction of cast iron promotes the removal of TCE from contaminated water by the concurrent sorption and reduction.     

高锰酸钾预处理微污染地表水研究

通过生产性试验考察了高锰酸钾预处理工艺对地表水中有机物、氨氮、铁、锰等污染物的去除效果,并与预氯化工艺进行了对比。结果表明,高锰酸钾预处理在减少铁锰污染、去除氨氮、降低有机物含量等方面具有比预氯化更好的效果。     

混凝/微滤用于反渗透海水淡化的预处理

考察了混凝/微滤工艺用于反渗透海水淡化预处理的可行性,并通过调整FeCl3和粉末活性炭(PAC)投量来确定最佳运行条件。结果表明,当FeCl3投量为2.5mg/L(以Fe3 计)、PAC耗量为40mg/L时处理效果最好,出水浊度<0.1NTU,污泥淤塞指数SDI<1.5,CODMn平均去除率为24%,满足反渗透的进水水质要求。此外,混凝及PAC的吸附作用可使海水中粒径<0.22μm的颗粒物变大,从而被微滤膜截留,这是出水水质良好的保证。     

瓷珠曝气生物滤池去除源水中氨氮研究

采用以瓷珠为填料的曝气生物滤池(BAF)预处理某高氨氮源水,结果表明,在气水比为1∶1、滤速为5. 5m/h、水温>10℃的条件下,当进水氨氮<5mg/L时BAF对氨氮的去除率为70% ~90%,反应器中存在一定的亚硝酸氮积累;反冲洗周期对氨氮的去除率有较大影响。     

组合工艺流程处理微污染源水研究

研究了由生物预处理、预臭氧化、常规处理和深度处理组成的八种工艺流程对深圳水库微污染源水的处理情况。试验结果表明,各工艺流程出水水质皆达到了国家建设部颁布的《城市供水行业２０００年技术进步发展规划》中规定的一类水司８８项水质标准的合格率。通过对各流程出水南的全面对比分析和研究表明,在各种工艺流程中,生物预处理＋常规处理＋臭氧生物活性炭工艺的出水水质最优。     

取样扰动对土的工程性质指标影响的试验研究

本文报道了取样扰动对土的工程性质指标影响的一批研究成果。采用100mm和75mm两种直径的取土器取样作对比试验以研究取土器扰动的影响。试验证明取土器直径对试样的孔隙比、压缩系数、超固结比和天然强度等指标都有明显的影响。采用两种预固结处理的方法以恢复原生应力状态,用不固结不排水试验比较了应力状态对天然强度的影响。对取土过程中土体应变的分布及其对土样扰动的影响用有限元方法进行了模拟。