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Journal of Environmental Sciences 2011年第7期23卷 1211-1218页

作者： Yongchao li tielong li Zhaohui Jin College of Environmental Science and Engineering Nankai University Tianjin 300071 China Key Laboratory of Pollution Processes and Environmental Criteria Ministry of Education of China

Effective in situ remediation of Cr（VI） in groundwater requires the successful delivery of reactive iron particles to the subsurface. Fe 0 nanoparticles （20–110 nm diameter） supported on silica fume were synthesized by borohydride reduction of an aqueous iron salt in the presence of a support material. The experimental result showed that attachment of Fe 0 nanoparticles on the commercial available sub-micrometer silica fume prevented them from aggregation while maintaining the particle reactivity. When the Fe 0 concentration was 0.4 g/L, 88.00% of 40 mg/L Cr（VI） was removed by silica fume-supported Fe 0 nanoparticles （SF-Fe 0 ） in 120 min, 22.55% higher than unsupported Fe 0 . Furthermore, transport experiments confirmed that almost all unsupported Fe 0 was retained, whereas 51.50% and 38.29% of SF-Fe 0 were eluted from the vertical and horizontal sand column, respectively. Additionally, the effect of solution ionic strength on the transport ability of SF-Fe 0 was evaluated. The result showed that increase in the salt concentration led to a decrease in the mobility and also the divalent ion Ca 2＋ had a greater effect than that of monovalent ion Na ＋ .

关键词： silica fume Fe 0 nanoparticles stability Cr（VI） removal transport

AZ31B镁合金连续铸轧板材搅拌摩擦搭焊接头组织研究

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热加工工艺 2024年第12期53卷 145-149,154页

作者：董芬李铁龙许宝卉王付杰运城学院机电工程系山西运城044000

对AZ31B镁合金连续铸轧板材进行搅拌头逆时针与顺时针相结合的二道搅拌摩擦搭接焊。经对其搭接接头横截面的焊缝宏观及不同部位微观组织对比来分析二道搅拌摩擦焊对焊接接头塑性组织及成形的影响。结果表明:焊核区等轴晶粒组织特别细小... 详细信息

对AZ31B镁合金连续铸轧板材进行搅拌头逆时针与顺时针相结合的二道搅拌摩擦搭接焊。经对其搭接接头横截面的焊缝宏观及不同部位微观组织对比来分析二道搅拌摩擦焊对焊接接头塑性组织及成形的影响。结果表明:焊核区等轴晶粒组织特别细小、均匀;过渡区晶粒组织大小起伏较大,略大于焊核,较小于母材组织;前进侧界面迁移呈现大弧度卷起,比较突兀与焊核隔断,形成钩状缺陷,而后退侧界面迁移线缓缓渗入中部焊核区,渐渐消失于焊核组织内;前进侧迁移线的成形特点相比于孔洞隧道缺陷,成为整个焊接接头最薄弱部分;前进侧界面迁移线边的组织融合影响了对焊接头的成形;二道搅拌摩擦搭接两次搅拌头旋转方向同为逆时针时,能得到表面良好、组织熔合紧密、强度较高接头;当搭接接头上板为后退侧时,与上板为前进侧相比,搭接接头能够承受更大剪切力。

关键词： AZ31B镁合金连铸板材搅拌摩擦搭接焊界面迁移

Dechlorination of Trichloroethylene in Groundwater by Nanoscale Bimetallic Fe/Pd Particles

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Journal of Water Resource and Protection 2009年第2期1卷 78-83页

作者： tielong li Shujing li Yongchao li Zhaohui JIN 不详

Palladium/iron bimetallic nanoparticles were synthesized using microemulsion method in the water-in-oil (W/O) microemulsion system, which was made up of iso-octane, cetyltrimethyl-ammonium bromide (CTAB), butanol and water and characterized by measuring the conductivity of the solution. Transmission electron microscope (TEM) and energy dispersive X-ray microanalysis (EDX) analysis showed that the av-erage diameter of synthesized palladium/iron bimetallic nanoparticles was less than 80 nm, which was much smaller than the particles produced by the solution method. The palladium/iron bimetallic nanoscale particles produced in the laboratory showed better performance on dechlorinating TCE than the other materials. The nanoscale Fe/Pd particles exhibited high reactivity. When Pd content is 0.5%, the best TCE dechlorination efficiency is achieved within 30min. And Fe/Pd nanoparticles show persistent reaction activity in some sense.

关键词： Trichloroethylene Microemulsion Nanoscale Pd/Fe Particles

Preparation of Nanoiron by Water-in-Oil (W/O) Microemulsion for Reduction of Nitrate in Groundwater

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Journal of Water Resource and Protection 2009年第1期1卷 16-21页

作者： tielong li Shujing li Shuaima WANG Yi AN Zhaohui JIN 不详

Nanometer-sized iron particles with monodispersity and narrow size distribution were synthesized by modi-fied microemulsion system using environment-friendly non-ionic surfactants Span 80 and Tween 60 as mixed surfactants. The synthesized iron nanoparticles were characterized by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the synthesized particles were mainly composed of α-Fe with an average diameter of 80-90 nm. The chemical activity of the obtained iron nanoparticles was evaluated by the denitrification of nitrate in water. On neutral condition, complete denitri-fication of nitrate was achieved by freshly synthesized nanoiron within 30 min. Ammonia was the main product, with good material balance at the end of the reaction. Two possible reaction pathways for nitrate reduction by nanoiron have been proposed in this study.

关键词： Iron Nanoparticles Microemulsion Reduction Nitrate

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鞣酸纳米铁去除六价铬的反应动力学研究

当代化工 2024年第3期53卷 577-581,586页

作者：单广波徐佰青蒋广安王山榕李铁龙刘海娣中石化(大连)石油化工研究院有限公司辽宁大连116045 南开大学环境科学与工程学院天津300350

通过添加不同剂量的鞣酸来制备鞣酸与铁离子摩尔比例分别为0.012 5、0.025 0、0.050 0、0.100 0、0.200 0的鞣酸纳米铁(TA-nZVI),通过TEM、UV-Vis、XRD、GT方法来分析不同比例TA-nZVI的形貌、粒径、成分、热稳定性。TA-nZVI是一种特殊... 详细信息

通过添加不同剂量的鞣酸来制备鞣酸与铁离子摩尔比例分别为0.012 5、0.025 0、0.050 0、0.100 0、0.200 0的鞣酸纳米铁(TA-nZVI),通过TEM、UV-Vis、XRD、GT方法来分析不同比例TA-nZVI的形貌、粒径、成分、热稳定性。TA-nZVI是一种特殊的团簇结构,粒径主要分布在40~70nm之间,比表面积可高达180.1 m^(2)·g^(-1),具有极高的反应活性,对Cr(Ⅵ)去除率在30 min内均可达到100%。TA-nZVI还原去除Cr(Ⅵ)的实验结果表明:不同鞣酸与铁离子摩尔比例条件下制备的纳米铁与Cr(Ⅵ)的反应均符合一级动力学,相同条件下,TA-nZVI的表观速率常数可达到Bare-nZVI的1 119倍,表面积归一化速率常数可达到Bare-nZVI的70.64倍。因此,TA-nZVI对Cr(Ⅵ)的高效去除不仅与其具有的巨大比表面积有关,而且也与其单位体积表面积内的Fe0的活性有关。

关键词：鞣酸纳米铁六价铬反应动力学

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单宁酸稳定纳米铁的制备及其迁移性研究

安全、健康和环境 2024年第2期24卷 22-30页

作者：单广波蒋广安徐佰青赵一山李铁龙刘海娣中石化(大连)石油化工研究院有限公司辽宁大连116045 南开大学环境科学与工程学院天津300350

制备了单宁酸与铁离子物质的量的比分别为0.0125,0.0250,0.0500,0.1000,0.2000的单宁酸稳定的纳米铁(TA-nZVI),通过TEM、XRD、Zeta和磁性来分析TA-nZVI的形貌、粒径、成分、稳定性和分散性。相对于未添加单宁酸为稳定剂制备的纳米铁(Bar... 详细信息

制备了单宁酸与铁离子物质的量的比分别为0.0125,0.0250,0.0500,0.1000,0.2000的单宁酸稳定的纳米铁(TA-nZVI),通过TEM、XRD、Zeta和磁性来分析TA-nZVI的形貌、粒径、成分、稳定性和分散性。相对于未添加单宁酸为稳定剂制备的纳米铁(Bare-nZVI),TA-nZVI是一种粒径主要分布在40~70 nm之间的特殊团簇结构,且随着单宁酸用量的增加,相应纳米铁颗粒的Zeta电位数值增加,颗粒的分散性和抗氧化性明显提高。通过研究TA-nZVI的沉降实验和迁移实验发现,随着单宁酸用量的增加,纳米材料的附着效率降低,颗粒在沙柱中处于“非有利沉降条件”,从而使颗粒的迁移能力得到显著提高。其中,单宁酸与铁离子摩尔比例为0.2000条件下制备的纳米铁颗粒通过动态柱实验后,总铁迁出率达到97.56%,几乎无截留现象,是相同条件下Bare-nZVI的17.96倍,具有一定的环保应用价值。

关键词：单宁酸纳米铁沉降迁移 X射线衍射

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电性矿物强化脱氯菌对水中TCE的降解

天津大学学报:自然科学与工程技术版 2023年第11期56卷 1177-1186页

作者：李铁龙谭鹏王薇南开大学环境科学与工程学院天津300350 南开大学沧州渤海新区绿色化工研究院沧州061108

针对地下水环境中脱氯菌污染修复周期长、电子供给难度大、易带来二次污染等问题,设计以天然矿物电气石的电场刺激、水解供氢和水体调节性能强化含脱卤拟球菌(Dehalococcoides spp.)的混合脱氯菌功能,通过将电气石和脱氯菌共同固定化,... 详细信息

针对地下水环境中脱氯菌污染修复周期长、电子供给难度大、易带来二次污染等问题,设计以天然矿物电气石的电场刺激、水解供氢和水体调节性能强化含脱卤拟球菌(Dehalococcoides spp.)的混合脱氯菌功能,通过将电气石和脱氯菌共同固定化,开发适用于地下水环境的生物强化原位修复技术.研究了共同包埋的电气石和脱氯菌对地下水典型有机污染物三氯乙烯(TCE)的降解性能.结果表明,在包埋材料海藻酸钠含量6%、凝固剂氯化钙含量6%、电气石含量1.0%、交联时间24 h条件下制得的固定化微球弹性好,机械强度高,粒径均匀分布在3~5 mm,具有多孔洞内结构和较为致密的外表面,既可提供电气石和细菌附着的场所,又能有效地防止微球内部菌体的流失.同时,包埋后的电气石仍能快速调节水体的pH和ORP,为厌氧脱氯菌提供适宜的生长代谢环境.无论是固定化还是分离体系,电气石的加入均增强了脱氯菌对TCE的还原脱氯效果,而电气石-脱氯菌共同固定化体系不仅能加快TCE的降解,在无外加电子供体的情况下仅180 h即可将16 mg/L的TCE完全去除,还显著促进了中间产物的进一步脱氯,反应800 h时终产物乙烯的转化率达到64%,比菌体系提升了1倍.电气石对共同包埋的脱氯菌更有效地起到了电场刺激和电子供体的作用,使其快速稳定的增殖.该复合固定化的应用方式促进了脱氯菌的富集及与电气石的接触,更加充分地发挥了电气石表面电场的直接和间接强化作用,可解决实际地下水修复过程中微生物和强化剂易分离失效的问题,促进地下水有机污染原位生物修复技术的发展.

关键词：电气石脱卤拟球菌固定化三氯乙烯产乙烯

Synthesis of nanoiron by microemulsion with Span/Tween as mixed surfactants for reduction of nitrate in water

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Frontiers of Environmental Science & Engineering 2007年第4期1卷 466-470页

作者： ZHANG Yunxia li tielong JIN Zhaohui WANG Wei WANG Shuaima College of Environmental Science and Engineering Nankai UniversityTianjin 300071China

Denitrification of nitrate in groundwater using iron nanoparticles has received increasing interest in recent years.In order to fabricate iron nanoparticles with homoge-neously spherical shape and narrow size distribution,a simple and“green”method was developed to synthesize iron nano-particles.The conventional microemulsion methods were modified by applying Span 80 and Tween 60 as mixed sur-factants.The maximum content of water in the Water-in-oil(W/O)microemulsion and its appropriate forming conditions were found,and then the microemulsion system consisting of saturated Fe^(2+)solution was used to synthesizeα-Fe ultrafine particles by redox reaction.The nanoparticles were characterized by using powder X-ray diffraction(XRD)and transmission electron microscopy(TEM).The results show that the average diameter of the particle is about 80-90 nm.The chemical activity of the obtained iron nanoparticles was studied by the denitrification experiment of nitrate.The results show that under the experimental conditions,iron removed most of the 80 mg/L nitrate within 30 min.The mass balance of nitrate reduction with nanoscale Fe indicates that endproducts are mainly ammonia.Two possible reaction pathways for nitrate reduction by nanoscale iron particles have been proposed in this work.

关键词： mixed surfactants microemulsion iron nanoparticles nitrate

Studies on catalytic reduction of nitrate in groundwater

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Frontiers of Environmental Science & Engineering 2007年第3期1卷 357-361页

作者： GENG Bing ZHU Yanfang JIN Zhaohui li tielong KANG Haiyan WANG Shuaima College of Environmental Science and Engineering Nankai UniversityTianjin 300071China

Catalytic reduction of nitrate in groundwater by sodium formate over the catalyst was investigated.Pd-Cu/c-Al2O3 catalyst was prepared by impregnation and charac-terized by brunauer-emmett-teller(BET),inductive coupled plasma(ICP),X-ray diffraction(XRD),transmission electron microscopy(TEM)and energy dispersive X-ray(EDX).It was found that total nitrogen was effectively removed from the nitrate solution(100 mg/L)and the removal efficiency was 87%.The catalytic activity was affected by pH,catalyst amount used,concentration of sodium formate,and initial concentration of nitrate.As sodium formate was used as reductant,precise control in the initial pH was needed.Exces-sively high or low initial pH(7.0 or 3.0)reduced catalytic activity.At initial pH of 4.5,catalytic activity was enhanced by reducing the amount of catalyst,while concentrations of sodium formate increased with a considerable decrease in N2 selectivity.In which case,catalytic reduction followed the first order kinetics.

关键词： catalytic reduction nitrate ammonium catalysis sodium formate

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热挤压AZ80镁合金板材的组织及力学性能

热加工工艺 2023年第15期52卷 31-33,37页

作者：李铁龙许宝卉运城学院机电工程系山西运城044000

对热挤压AZ80镁合金板材进行了金相组织、显微硬度、拉伸及断口扫描试验,探讨了热挤压板材的组织与力学性能。结果表明:板材纵向组织偏析严重,板材边缘组织与板材中心组织差异较大,板材中心组织纵向延伸较大,具有很强方向性,而板材横向... 详细信息

对热挤压AZ80镁合金板材进行了金相组织、显微硬度、拉伸及断口扫描试验,探讨了热挤压板材的组织与力学性能。结果表明:板材纵向组织偏析严重,板材边缘组织与板材中心组织差异较大,板材中心组织纵向延伸较大,具有很强方向性,而板材横向组织差异不明显;同时显微硬度值在板材边缘较小,而在板材内部较大,在厚度方向呈两边小中间大的分布,这些表明板材具有明显的各向异性;板材纵向抗拉强度高达384 MPa,伸长率较低,为10.81%;板材断口微观形貌呈现内部很深的卵性韧窝,属于韧性断裂。

关键词： AZ80镁合金热挤压板材金相组织显微硬度抗拉强度