Fate of aluminium released by sacrificial anodes – Contamination of marine sediments by environmentally available compounds     

《Comptes Rendus Geoscience》2018,350(5):195-201

To protect their steel structures from corrosion by cathodic protection, many harbours use aluminium sacrificial anodes, which induces aluminium release and potential contamination of the surrounding waters and sediments. To study the impact on Al mobility, a natural marine sediment was artificially contaminated with aluminium from different sources: sulphate or chloride salts, or sacrificial anodes. To estimate Al mobility in sediments, single (HCl) and sequential (F6) extractions were performed; they highlighted that aluminium is poorly mobile in natural sediment (HCl-leachable: 2% and F6-leachable: 9%). Contamination by aluminium salts inhibits HCl-leachability (≤ 2%), whereas the Al F6-leachability is intensified up to 18%, suggesting that the additional aluminium is scavenged in a mobile fraction that HCl is not able to solubilise. In case of aluminium anode contamination, sediments present surging Al HCl-leachable (15%) and F6-leachable (32%) fractions, which are related to aluminium mineralogical speciation. Indeed, contrary to the Al naturally present or introduced by salts, Al released by anodes is partly bound to the acid-soluble fraction, probably because of the integration of the released Al into the calcareous deposit produced at the anodes surfaces that finally comes away and gets mixed up with the sediment. The presence of aluminium in the acid-soluble fraction of sediments could have an important environmental impact as this fraction is easily available. Indeed, Al scavenged in the acid-soluble fraction of sediments participates in enhancing Al lability near the sacrificial anodes and may affect the surrounding ecosystems.  相似文献   

华南渣拉沟剖面纽芬兰世沉积水体氧化还原状态演化   总被引：2，自引：0，他引：2  

向雷  蔡春芳  贺训云  姜磊  袁余洋  于雷 《地质学报》2015,89(6):1120-1133

为研究纽芬兰世斜坡一盆地环境背景下的水下隆起的沉积水体氧化还原性质的垂向演化,本文选取黔东南渣拉沟剖面,进行总有机碳含量(TOC)、铁组分、黄铁矿硫同位素(δ~(34)S_(py))、干酪根的碳和硫同位素(δ~(13)C_(kero)、δ~(34)S_(kero))等方面的分析。本文依据硅质岩、磷块岩、多金属硫化物层和干酪根碳同位素等对比标志,对渣拉沟剖面进行地层对比,认为:渣拉沟剖面本文分析层段大体与滇东纽芬兰世石岩头组的中下部相对应。铁组分和TOC/S_(py)显示渣拉沟剖面老堡组硅质岩段处于缺氧非硫化环境,其上覆的渣拉沟组分析层段以硫化环境为主,其间间断性的发育缺氧非硫化环境,并最终回复到缺氧非硫化环境。δ~(34)S_(py)与δ~(34)S_(kero)在老堡组的缺氧非硫化环境都较渣拉沟组中的硫化环境重,可能与前者的细菌硫酸盐还原反应主要发育在相对封闭的孔隙系统,后者的细菌硫酸盐还原反应主要发育在相对开放的沉积水体有关。  相似文献   

应用扫描电镜与X射线能谱仪研究黔北黑色页岩储层孔隙及矿物特征   总被引：3，自引：2，他引：1  

王坤阳  杜谷  杨玉杰  董世涛  喻晓林  郭建威 《岩矿测试》2014,33(5):634-639

页岩储层研究已经成为页岩气研究的重点,页岩组构特征的特殊性使得页岩储层发育纳米/微米级孔隙。岩石及矿物中的纳米/微米级空隙是黔北黑色页岩的结构组分之一,传统的光学显微镜方法由于分辨率及放大倍数的限制无法对页岩储层的孔隙类型进行观察;核磁共振等仪器虽能准确测试页岩储层的孔隙度,但是无法获得孔隙的形貌及分布特征等信息。本文整合扫描电镜微区分析与X射线谱学分析的优点,运用Hitachi S-4800型场发射扫描电镜与IE250X-Max50牛津能谱仪组合,对黔北黑色页岩储层中矿物的分布、形态特征及矿物的组成元素进行分析测试。分析结果表明,利用场发射扫描电镜发现黑色页岩中发育微裂缝、纳米/微米级粒内溶孔;通过X射线能谱发现黑色页岩矿物主要有伊利石、石英、钠长石,其次为绿泥石、白云母、白云石等。黔北黑色页岩中裂隙直径为0.1~20μm,其中主要分布在1~5μm,均大于甲烷分子直径(0.414 nm),因此可作为天然气的运移通道与储集空间。此外通过X射线能谱仪对黔北黑色页岩中的石英、方解石、白云石、伊利石等脆性矿物进行分析,发现石英的含量(9.1%~78%)较高,伊利石(17.6%~25.5%)等黏土矿物含量较低,所以该页岩具有很高的脆性,易产生裂缝,可为游离气提供运移通道及储集空间,提高页岩气的产能及储量,进而为黔北地区储层评价及预测等提供依据。  相似文献   

污泥/煤流化床混烧底灰中的重金属毒性研究     

赵晓莉  朱伟  徐德福  邱林倩  张超  杨创 《南京气象学院学报》2013,5(3):244-250

研究了污泥与煤按不同质量比例混烧后,底灰中的重金属形态分布与浸出毒性.结果表明:30:70的泥煤比使底灰中重金属硫化物及有机态和残渣态所占比例最大,即生物无效部分比例最大;在浸出毒性实验中,30:70的泥煤比使底灰重金属浸出量最小.由此推出,对环境毒害程度最小的泥煤质量比为30:70,即该实验条件下最优泥煤质量比为30:70.  相似文献   

Simplified synthesis of an 8-hydroxyquinoline chelating resin and a study of trace metal profiles from Jellyfish Lake, Palau     

Holger Dierssen  Wolfgang Balzer  William M. Landing   《Marine Chemistry》2001,73(3-4)

We report a simplified synthesis, and some performance characteristics, for 8-hydroxyquinoline (8-HOQ) covalently bonded to a chemically resistant TosoHaas TSK vinyl polymer resin. The resin was used to concentrate trace metals from stored, acidified seawater samples collected from Jellyfish Lake, an anoxic marine lake in the Palau Islands. The Mn, Fe, and Zn profiles determined from the 8-HOQ resin extraction were similar to those determined using Chelex-100 resin. The Zn and Cd profiles did not exhibit removal by sulfide “stripping” in contrast to other anoxic marine basins. The profiles of Co and Ni also exhibited elevated concentrations in the anoxic hypolimnion. The solution speciation and saturation states for the metals were calculated using revised metal-bisulfide stability constants. The calculations suggest that the MS(HS)⁻ species dominates the solution speciation for Mn, Co, Ni, Zn, Cd, and Pb. Cu(I) is modeled as the CuS⁻ or Cu(HS)₂⁻ species, while Fe(II) behaves as the free Fe²⁺ cation. The Mn, Co, Ni, Cu and Cd concentrations appeared to be at least 10-fold undersaturated, while the Fe(II), Zn, and Pb concentrations were close to saturation with respect to their metal sulfides.  相似文献   

新疆某地浸砂岩型铀矿中铀赋存形态的研究   总被引：3，自引：2，他引：1  

马强  冯志刚  孙静  谢二举  李小军 《岩矿测试》2012,31(3):501-506

以新疆某地浸砂岩型铀矿为研究对象,参考Tessier逐级化学提取方法,对10件矿芯试样进行铀赋存形态的研究。将铀赋存形态分为可交换离子态、碳酸盐结合态、铁锰氧化物结合态、硫化物及有机物结合态和残渣态,其中前4种形态铀为活性铀,残渣态铀为惰性铀。研究结果显示,无论是试样间还是同一试样内,铀的形态分布特征都存在明显的差异。各形态铀的含量(平均值)占总量铀的比例为:残渣态(37.75%,RSD为1.80%)>碳酸盐结合态(20.56%,RSD为2.72%)>可交换离子态(15.51%,RSD为1.85%)>硫化物及有机物结合态(14.26%,RSD为2.08%)>铁锰氧化物结合态(11.91%,RSD为1.75%),表明残渣态铀是砂岩型铀矿石中铀的重要赋存形式。针对目前酸法地浸工艺,活性铀是可被浸出的部分,而惰性铀对资源回收是无效的,对于残渣态铀所占比例较高的铀矿石,铀的浸出值较低,在地浸过程中依靠提高溶浸剂的酸度和增加氧化剂对提高浸出率是无益的。  相似文献   

生物样品中硒形态分析前处理技术     

张绿茵  余晓平  郭亚飞  邓天龙 《岩矿测试》2012,31(3):407-412

样品前处理过程在硒形态分析中至关重要。文章对生物样品中硒形态分析的前处理方法,包括液相萃取、微波辅助萃取、固相微萃取、液相微萃取等及其应用进行归纳总结,指出了痕量、超痕量硒形态分析前处理技术的未来发展方向主要集中在满足简单、快速和环境友好的自动化处理,并着重于样品前处理的各种萃取技术在线耦合以及与硒形态分析检测器联用技术。  相似文献   

江西省鄱阳湖流域根系土硒形态分析及其迁移富集规律   总被引：5，自引：0，他引：5  

魏然  侯青叶  杨忠芳  尹国胜  衷存堤  邓国辉  马逸麟 《物探与化探》2012,(1):109-113

对江西省鄱阳湖流域根系土中硒的形态分析表明,根系土中Se的强有机态、腐植酸结合态约占Se全量的66.23%,残渣态占12.32%,3种形态均与根系土Se全量呈极显著的线性正相关。根系土Se全量受pH值的影响不明显,但受有机质含量的影响很大,线性回归关系极显著,说明岩石风化、土壤发育过程中,有机质吸附Se,致使Se较其他元素流失比例少,造成根系土中Se相对富集。同时,提出了利用全量Se推导Se各形态值的方法,建立了土壤Se全量与各形态间的关系模型和决定土壤有效态Se的公式,建议在评价土壤Se时只用考虑有机结合态Se、残渣态Se、水溶态Se和全量Se。  相似文献   

Sulfur Speciation in Hydrothermal Fluids     

NI Huaiwei  Hans KEPPLER 《《地质学报》英文版》2013,87(Z1):263-263

  相似文献   

Variations in Phosphorus Speciation in Response to Simulated Riparian Zone Enhancement with Red Mud to Treat Reclaimed Water     

Jing Qin  Ping Liu  Gang Wu 《洁净——土壤、空气、水》2012,40(12):1334-1340

Variations in phosphorus speciation in two sets of simulated riparian zones with and without Perennial ryegrass were compared. Each set consisted of four units, each measuring 700 mm × 200 mm × 200 mm, which were enhanced with 0, 2.5, 5, and 7.5% red mud (RM) by weight. The levels of total phosphorus (TP), total dissolved phosphorus (TDP), soluble reactive phosphorus (SRP) in the effluent were analyzed, and phosphorus fractionation in the media were also determined after the systems had been operational for 3 months. The results showed that the unit received 2.5% RM had the highest rate of phosphorus removal, including TP, TDP, SRP, particulate phosphorus (PP), and dissolved organic phosphorus (DOP) were present at the average concentrations of 0.17, 0.10, 0.07, 0.08, and 0.03 mg/L in the effluent. Sequential phosphorus fractionation showed that calcium‐bound phosphorus (Ca–P) was the major component, indicating that the addition of RM induced aluminum/iron‐bound phosphorus (Al/Fe–P), which was intensely bioactive, to form intractable Ca–P, which further inhibited the release of phosphorus from the media. However, the presence of P. ryegrass had little effect on the removal of phosphorus. Therefore, RM, when used directly in riparian zones at a suitable concentration, is a novel and low cost additive material that can be used to remove phosphorus from reclaimed water.  相似文献