海水淡化装置内舱碳钢防护涂层寿命预测研究

目的获得海水淡化装置内舱碳钢防护涂层的耐热老化寿命。方法通过调整设备的温度及压力,模拟低温多效蒸发器半浸区工作环境,进行为期20个月的浸泡加速试验。以涂层的附着力随老化时间的变化情况、涂层颜色变化情况、涂层浸泡前后微观形貌和阻抗值为评判依据,在老化经验公式的基础上进行外推计算,进行涂层热老化寿命预测。结果该涂料在该区域经过20个月的挂片试验,涂层表面均未出现起泡、锈蚀、开裂、脱落等失效现象;表面色差变化趋势相对稳定;干态附着力为10.9 MPa,经过20个月的测试,附着力为8.95 MPa;0.01 Hz低频阻抗(|Z|0.01 Hz)条件下,其电化学交流阻抗值由浸泡前的1.8×10^8Ω·cm^2下降为浸泡后的7.9×10^6Ω·cm^2。涂层阻抗的数量级虽有所下降,但仍然具有较高的阻抗值,具有较好的保护性能。经过老化经验公式进行外推计算,预测海水淡化装置内舱碳钢防护涂层的热老化寿命为13.33年。结论海水淡化装置内舱防护涂料具有长寿命热老化重防腐作用。     

石墨烯薄膜原子氧剥蚀行为及电阻特性

目的研究石墨烯薄膜在原子氧空间环境的适应性,为其在航天器上应用提供参考。方法采用刮涂法制备石墨烯薄膜,将石墨烯薄膜材料及石墨烯电阻传感器置于微波源原子氧设备内开展原子氧试验,原子氧剂量分别为3.0×10^20 atoms/cm2和7.5×10^20 atoms/cm^2,研究薄膜表面形貌、结构、成分及电阻性能的变化。结果采用刮涂法可制备氧含量较低的石墨烯薄膜,原子氧剂量为7.5×10^20 atoms/cm^2情况下,石墨烯薄膜的厚度损失为5.3μm,原子氧反应率为7.14×10^-25 atoms/cm^3。原子氧作用后,石墨烯薄膜中碳原子无序程度增大,C—O、—COOH官能团含量降低,C=O官能团含量增加。石墨烯电阻传感器的R0/R比值随原子氧剂量增加线性降低,0.8μm厚度薄膜可探测最大原子氧剂量为5×10^19 atoms/cm^2,增加薄膜厚度有望提高传感器的使用寿命。结论得到了石墨烯薄膜厚度损失、原子氧反应率、微观结构及电阻特性的变化规律,可为石墨烯薄膜的空间应用提供技术支撑。     

典型金属材料深海腐蚀行为规律与研究热点探讨

综述了碳钢与低合金钢、不锈钢、铜合金、铝合金以及钛合金等典型金属材料深海腐蚀行为规律的研究进展。结合深海环境的苛刻与独特性,探讨了深海腐蚀环境试验及实海原位电化学测试技术等领域研究方向,尤其是中国临近海域深尺度、涵盖当前实际需求材料的大规模深海环境试验以及耐受高静水压、集电化学数据采集与远程数据传输于一体的实海电化学测试技术。此外,从阴极保护、仿真预测、应力腐蚀、涂层防护等方面介绍了实验室深海模拟试验方面的研究热点,进一步展望了典型材料深海腐蚀数据积累及适用性研究发展前景。     

车辆装备涂层局部微小破损对防护性能的影响研究

目的探究车辆装备有机涂层在微小破损之后性能的变化情况,并通过完好涂层防护能力的对比分析,间接预测微小破损涂层的服役寿命。方法利用某型现役装备涂层作为试验样本,进行综合环境下的循环加速腐蚀试验,最后利用EIS分析实验数据,分析两者防护性能的差别。结果完好涂层与破损涂层的防护性能均出现了大幅度的下降,两者在经过10个周期的腐蚀试验之后,都失去了防护能力,出现了大面积锈迹。完好涂层的低频阻抗模值|Z|0.1 Hz在试验初期处于1010Ω·cm2数量级,最后下降到106Ω·cm2以下;初始状态破损涂层的低频阻抗模值|Z|0.1 Hz为1.2×105Ω·cm2,9个腐蚀周期之后下降至5.7×103Ω·cm2,下降了2个数量级。结论破损涂层在腐蚀初期更多地表现出电容性质,其试验初期的防护能力大约相当于完好涂层经历6~7次循环试验之后的防护能力,破损部分随着腐蚀周期的变化呈现“钝化—溶解—再钝化—再溶解”的周期性变化规律。     

油罐常用环氧煤沥青涂层的防护寿命研究

利用电化学阻抗谱（EIS）测试技术,研究储油罐起防护作用的环氧煤沥青涂层逐渐被破坏后的阻抗变化规律。结果表明,涂层上孔洞面积增大到一定程度时,10mHz频率处10^3Ω数量级的总阻抗值是判定环氧煤沥青涂层防护性能失效的量值。     

TC21钛合金表面涂层体系在多因素综合加速试验条件下的老化规律研究

目的 研究TC21钛合金表面防护体系(酸洗+环氧底漆+聚氨酯面漆)在多因素协同加速试验条件下的表面性能变化规律。方法 利用一台海洋大气综合模拟试验装置,在户内模拟热带岛礁海洋大气环境,对经历各个加速试验周期后的试样进行外观拍照、光泽度测试、色差测试、光学显微拍照、以及电化学阻抗测试(EIS),并描述相关变化过程。结果 5个周期的加速试验后,试样表面涂层的失光率和色差分别达到45.6%和4.36。涂层在0.01 Hz处的阻抗模值由初始的2.74×10¹⁰ Ω下降为6.21×10⁷ Ω。结论 经历5个周期的户内多因素综合加速试验的过程中,TC21钛合金表面涂层体系的防护效果呈持续下降趋势,但5周期后尚未完全失效。     

沿海地区输电铁塔防护涂层耐腐蚀性能研究

目的研究沿海地区输电铁塔防护涂层体系的腐蚀失效行为,评估涂层的防护性能,为铁塔防护涂层寿命体系评定和修复提供试验依据。方法分别采用热镀锌、热镀锌/冷涂锌复合涂层、热镀锌/带锈环氧涂层三种技术方案,对铁塔角钢材料进行防腐保护,采用中性盐雾方法模拟沿海环境对试样进行耐蚀性测试,通过试样表面形貌观察、极化曲线、以及阻抗谱等电化学手段对保护效果进行评价。结果热镀锌、热镀锌/冷涂锌复合涂层在盐雾150 h出现大面积腐蚀,热镀锌/带锈环氧涂层在盐雾2000 h未发生明显腐蚀。结论热镀锌/带锈环氧涂层的耐蚀性能优于热镀锌/冷涂锌漆和热镀锌涂层。     

环境因素对硅烷环氧杂化树脂涂层/LY12铝合金间附着力时效性的影响分析

目的研究不同环境因素对硅烷环氧杂化树脂涂层/LY12铝合金间附着力时效性的影响规律。方法制备涂层厚度为30μm的样板,采用拉拔测试仪测试不同环境因素(温度、湿度及酸碱溶液)、不同时间段下涂层/基体间的附着力值,研究环境因素对该涂层/基体间附着力时效性的影响。结果低温或高温环境下,涂层暴露时间越长,其附着力下降程度越大;在湿热环境下,随着试验周期的增加,涂层的附着力明显削弱;酸碱溶液对于涂层体系破坏较为严重。结论环境因素对于硅烷环氧杂化树脂涂层/LY12铝合金间附着力的影响时效性,较为严重的是高低温、酸盐溶液。     

环氧涂层在不同温度海水中的失效行为研究

目的研究环氧涂层在不同温度海水环境中的腐蚀失效行为。方法采用电化学阻抗谱(EIS)技术研究两种海水环境中涂层的EIS特征,同时分析涂层电阻和涂层电容的变化,以研究环氧涂层防护性能随浸泡时间的变化。结果涂层在15℃海水中浸泡1440 h时,阻抗值下降至106?·cm2以下,而在30℃海水中仅浸泡72h时,阻抗值就已下降至106?·cm2。随着浸泡时间的增加,涂层在15℃海水中的EIS响应由高阻抗的单容抗弧变为双容抗弧,而在30℃的海水中,EIS响应首先由单容抗弧演变为双容抗弧,随后又出现了明显的Warburg扩散阻抗特征。涂层电容在两种温度的海水中均呈上升趋势,电阻呈下降趋势。结论涂层在30℃海水中的劣化速度加快,是因为升高温度能够降低涂层与金属间的结合力,加快了海水向涂层内部渗透的速率。由于温度的升高加快了溶解氧的扩散速率,使得氧扩散过程成为腐蚀反应的控制步骤,从而导致了涂层在30℃海水中的EIS响应出现了明显的Warburg扩散阻抗特征。当环氧涂层在15℃与30℃的海水中浸泡1800 h时,其防护性能的变化可以分为快速下降、缓慢下降、趋于稳定三个阶段。     

铝合金牺牲阳极深海应用性能研究

目的评价铝合金牺牲阳极在深海环境的电化学性能。方法通过利用中国船舶重工集团公司第七二五研究所深海试验技术和装置,原位测量三种铝合金牺牲阳极在南海1200 m深海环境的电化学性能。结果三种阳极在1200 m深海环境下的开路电位均在?1.17 V左右,工作电位在?1.11～?0.91 V范围内。1#和2#阳极的实际电容量小于2400A?h/kg,电流效率约为80%,表面存在明显的优先溶解和晶粒脱落现象,表面腐蚀产物有结壳现象发生。3#阳极的实际电容量约为2500A?h/kg,电流效率大于85%,表面微观溶解形貌相对均匀,但表面存在大面积未溶解区域,且腐蚀产物不易脱落。结论该研究结果为深海工程装备阴极保护设计提供了支撑。     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.