共查询到19条相似文献，搜索用时 109 毫秒
1.
选取胶州湾海域2个站点的沉积物进行了表面酸碱电位滴定实验,并考察了人工海水介质中对铜离子的吸附性能,比较了介质的盐度和温度等对吸附动力学曲线和吸附等温线的影响.结果发现:2个站点的沉积物随pH值由3增大到10表面质子电荷密度的值由正转负,零净质子电荷点pHPZNPC均在4.0～4.5之间,表面位浓度Hs在1.34×104～1.90×10-4 mol·L-1之间;沉积物对铜离子的动力学吸附曲线可用伪一级动力学方程、伪二级动力学方程、Elovich方程、双常数速率方程拟合,其中伪二级动力学方程符合较好,吸附在2h左右达到平衡;吸附等温线可用Langmuir等温式拟合.零净质子电荷点低、表面位浓度大的沉积物对铜离子的吸附能力较强.蒸馏水介质中,沉积物对铜离子的饱和吸附量小于在稀释人工海水中和人工海水中的结果;较高的温度使饱和吸附量增大. 相似文献
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选取胶州湾海域2个站点的沉积物进行了表面酸碱电位滴定实验,并考察了人工海水介质中对铜离子的吸附性能,比较了介质的盐度和温度等对吸附动力学曲线和吸附等温线的影响。结果发现:2个站点的沉积物随pH值由3增大到10表面质子电荷密度的值由正转负,零净质子电荷点pHPZNPC均在4.0～4.5之间,表面位浓度HS在1.34×10-4～1.90×10-4mol.L-1之间;沉积物对铜离子的动力学吸附曲线可用伪一级动力学方程、伪二级动力学方程、Elovich方程、双常数速率方程拟合,其中伪二级动力学方程符合较好,吸附在2 h左右达到平衡;吸附等温线可用Langmuir等温式拟合。零净质子电荷点低、表面位浓度大的沉积物对铜离子的吸附能力较强。蒸馏水介质中,沉积物对铜离子的饱和吸附量小于在稀释人工海水中和人工海水中的结果;较高的温度使饱和吸附量增大。 相似文献
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采用负载镧的乙二醇二缩水甘油醚(EGDE)交联壳聚糖微球对含氟水进行吸附处理.该吸附剂的适宜工作条件为:温度30～50℃,pH值7.0,吸附时间30 min.用吸附等温线描述了F-在吸附剂上的吸附平衡,并用动力学模型研究了其吸附动力学机制.结果表明:吸附剂对F-的吸附平衡符合Langmuir吸附等温线和Freundlich吸附等温线,饱和吸附容量为25.7mg·g-1;该吸附剂对F-的吸附既包含化学吸附又包含物理吸附过程,以单分子层的化学吸附为主;吸附动力学符合拟二级动力学方程,吸附过程受化学吸附机理的控制,颗粒内扩散和液膜形成的边界层是其限速步骤. 相似文献
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选取长江口邻近海域的沉积物风干研磨后筛分为4个不同粒度的样品(40~80目,80~100目,120~200目及200目以下),考察粒度及磷浓度对动力学吸附的影响,比较了处理方式、介质pH及所含腐殖酸HA对等温吸附的影响。结果发现:(1)沉积物对磷的吸附可用伪二级动力学方程描述,沉积物粒度越小、初始磷浓度越大,对磷的吸附速率越大;(2)等温吸附曲线可用Langmuir-交叉型等温式拟合,磷的吸附量随粒度减小而增加。沉积物经HCl处理之后,对磷的吸附能力增强,沉积物对磷的吸附量与介质中HA的浓度正相关,pH对沉积物吸附磷的影响较为复杂,"稳定pH范围"约为7~9。 相似文献
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本文研究了不同pH、反应时间、温度、初始糖浓度条件下溶液中褐藻胶低聚糖（AOS）在活性炭上的吸附性能及其吸附动力学和热力学机制。结果表明，溶液pH对活性炭吸附AOS具有重要影响，随pH降低，AOS在活性炭上的吸附增强，pH=1时吸附量可达0.116 g/g。吸附反应在5 min内迅速发生，60 min后达到吸附平衡。活性炭吸附AOS符合准二级吸附动力学过程。吸附热力学研究表明，吸附过程为自发的放热反应，吸附等温线符合Langmuir模型。综上，吸附过程为单分子层均相吸附，降低pH、低温有利于AOS在活性炭上的吸附。 相似文献
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黄河口沉积物重金属含量变化特征研究 总被引：11，自引：0，他引：11
在黄河口的平水期、枯水期和丰水期采集沉积物样品。分析了铜、铅、锌、镉、铬、砷、汞浓度.结果表明,黄河口沉积物样品中的重金属含量由河到海呈现先上升后下降的趋势,平水期和枯水期Cd、Cr、As呈显著相关(0.01水平)。重金属含量为平水期>枯水期>丰水期。水文特征严重影响到沉积物中重金属的迁移。沉积物中重金属含量和沉积物的粒度密切相关.粒度越小重金属含量越高,反映了河流沉积的特征。沉积物中重金属浓度较低。各项目基本上都符合海洋沉积物质量一类标准。 相似文献
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黄河口磷酸盐缓冲机制的探讨Ⅲ.磷酸盐交叉缓冲图及"稳定pH范围" 总被引：8，自引：1，他引：7
于 1 994年 5月— 1 995年 6月在实验室进行了不同磷酸盐浓度、pH条件下的悬浮物吸附解吸模拟实验 ,对黄河口磷酸盐的缓冲机制进行了探讨。黄河口悬浮物对磷酸盐的吸附量 (解吸量 )随磷酸盐浓度的增大而增大 (减小 ) ,零平衡时磷酸盐浓度 (EPC0 )值在 0 .4— 1 .3μmol/dm3之间 ,且随温度的升高和悬浮物粒度的增大而略有减小。黄河口悬浮物的线性吸附系数 (K)在 0 .0 3— 0 .40dm3/g之间 ,且随温度的升高呈线性关系增加 ,随悬浮物粒度的减小呈指数形式增加。盐度对EPC0 和K基本没有影响。在pH对黄河口悬浮物吸附和解吸磷酸盐的影响实验中 ,首次发现在pH约为 7.7— 9.3范围内存在“稳定pH范围” ,在此范围内悬浮物对磷酸盐的吸附量和解吸量不随水体pH值发生变化。此范围的大小和位置随实验条件不同而略有变化 ,稳定pH范围随温度的上升有所减小且左移 (pH减小方向 ) ,随着悬浮物粒度的增大稳定pH范围有所增大且右移。 相似文献
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黄河口沉积物对磷酸盐的吸附与释放 总被引：44，自引：2，他引：44
本文对黄河口典型沉积物进行了吸附磷及释放磷的研究,结果表明黄河口地区浅海沉积物对磷的释放极少.阴离子表面活性剂的存在能降低对磷的吸附能力,溶液pH的增大对吸附量有增大的作用,硝酸盐的存在不影响沉积物对磷的吸附.沉积物吸附大量磷后的再释放是缓慢的.经测定,沉积物吸附/解吸平衡点一般为0.24～4.27μmol/dm3,此值一般高于底层水磷浓度,因此我们推测除粗颗粒样品外,黄河口地区浅海沉积物有向上覆水释放磷的倾向. 相似文献
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The adsorption of Pb, Cu and Cd on synthetic hydrous ferric oxide (HFO) has been performed under simulated environmental conditions of the Changjiang Estuary. An improved M2 - H exchange-adsorption model is proposed to explain the adsorption processes. The adsorption of these elements falls in the order: Pb ≥ Cu > Cd and has a good coincidence with the field results obtaimed from the Estuary. It has been concluded that the adsorption processes of Pb and Cu on HFO are mainly chemical actions, whereas static-electrical action dominates in the case of Cd. 相似文献
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Concentrations of P and of heavy metals (Zn, Cd, Pb, Cu) were determined in sediment cores from the Peel-Harvey Estuary in Western Australia. Two cores were extracted, each representing one of the two basins of the estuary. Sediments were dated by surplus210Pb, by137Cs and by changes in the Fe/S ratio. Increasing exports of P from the mainly agricultural catchments have resulted in more than a doubling of both total P and acid extractable inorganic P in sediments of the estuary. Accumulation of P in the estuary is less than expected for complete retention of inputs of P from the major tributaries. Historical data show that since 1950 average concentrations of dissolved inorganic P have approximately doubled in the Peel Inlet and increased by times seven in the Harvey Estuary. Increases in concentrations in surface sediments of acid extractable Zn, Cd, Pb and Cu are noticeable in the Peel Inlet, and of Zn and Cd in the Harvey Estuary. The greatest increase, relative to background, is shown by Zn. Concentrations of extractable Zn and Cd in surface sediments are similar to those estimated from average concentrations in the water column for equilibrium adsorption to organic matter in sediments. Extractable Pb is greater than estimated for equilibrium adsorption to sediments. Extractable Cu is of the order of what can be expected for equilibrium adsorption to sediments in the Peel Inlet, but is less than expected in the Harvey Estuary. 相似文献
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The process of adsorption of metal ions by immobilized marine algae with the existence of clay was investigated. It can be noted from the results that, after mixing with clay, the adsorption rate increases rapidly with the increasing amount of the marine algae. When pH=5, the best ratio between the clay and the marine algae is 1：4 for Pb^2＋. The result of in situ handling of the waste water containing heavy metals shows that the average adsorption rates of heavy metal irons Cu^2＋, Cd^2＋, Pb^2＋ and Ni^2＋ are all over 70 %. 相似文献
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The thermodynamic process of two macroalgae, Sargassum fusiforme and Lamin aria japonica, absorbing heavy, metal ions Cu^2 , Pb^2 , Cd^2 and Ni^2 . has been studied. The result indicates that the absorption isotherms of these two macroalgae clearly accord with the Landmuir adsorption model. The absorptive processes of S. fusiforme and L. japonica for Cu^2 are endothermal, and at 35℃, the adsorption heat of these two algae is 59.5kJ/mol and 76.8 kJ/mol respectively. Temperature could affect the algae‘s adsorption capacity. Their adsorption capacity increases with temperature (25℃ and 35℃). 相似文献
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The comparison of spatial and temporal distribution of Hg, Cd, Pb, Cu, Ni, Zn, Mn and Fe concentrations in sediments from the Gulf of Riga and open Baltic Sea along the coastal zone is presented for the first time. There were considerable differences in Pb, Zn, Mn and Fe levels in sediment at various stations of the Gulf of Riga. A significant difference of Cd, Pb, Cu, Ni, Zn levels was found in sediments of various stations in the open Baltic coast. The amount of Cd, Pb, Cu, Ni, Zn and Fe levels also differed significantly in the sediments of the Gulf of Riga in different years. A considerable yearly difference in amount of Hg, Cd, Pb, Cu, Ni and Mn levels was found in sediments in the open Baltic coast. The essential highest values of Pb and Zn in coastal sediments of the open Baltic Sea are stated in comparison with the Gulf of Riga. The concentrations of other metals have only a tendency to be higher in coastal sediments of the open Baltic Sea in comparison with the Gulf of Riga. Natural and anthropogenic factors were proved to play an important role in determining resultant metals concentrations in the regions. 相似文献
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The adsorption kinetics of Pb, Cu and Cd on hydrous ferrk oxide (HFO) has been approached in tthe simulated environmental conditions of the Changjiang Estuary. The forward adsorption rate constants of different systems under different temperatures have been determined, and the activation energies of the adsorption for Pb and Cu evaluated (Pb=7 kcal/mol, Cu= 11 kcal/mol). The results show that Pb and Cu are strongly adsorbed by HFO; the order of their adsorption rate is found to be Pb≥Cu≥Cd, which follows thte order of their theonody-namic equilibrium constants. It has been demonstrated that the surface exchange-adsorption is the determining step of the solid-liquid interface process. The field investigation results are theoretically explained by the kinetic mechanism. 相似文献
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Peter H. Santschi Scott Nixon Michael Pilson Carlton Hunt 《Estuarine, Coastal and Shelf Science》1984,19(4):427-449
The accumulation of sediments, trace metals and hydrocarbons has been estimated from the analysis of the sediment from six coring sites in Narragansett Bay. Radionuclides (234Thxs, 210Pbxs, 239,240Pu) with known input functions and trace metals (Cu, Pb) were used. We estimate that 6·9 × 104 tons of sediments, 51–90 tons of Pb, 72–100 tons of Cu and 400–1000 tons of total hydrocarbons accumulate annually under present conditions in the bay. This represents 64–117% (Pb), 89–123% (Cu) and 23–58% (hydrocarbons), respectively, of present day inputs to the bay. Furthermore, close to 100% of the particle-reactive radionuclides 210Pb and 239,240Pu accumulate in the bay. Present day inputs to the bay were calculated independently as 77–80 tons Pb and 81 tons of Cu. Sewage effluents were the dominant source of Cu, whereas atmospheric deposition and urban runoff were most important for Pb. Dredging activities by the U.S. Army Corps of Engineers between 1946 and 1971 removed more sediments from the bay than would have accumulated during the same time in the undredged areas of the bay. Copper smelting and coal mining on the shores of the upper bay during 1866–1880 left an imprint in the sediments which is still evident. Model derived accumulation rates of Pb, Cu and coal during that time were 3–4 times present-day inputs. 相似文献
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西北冰洋表层沉积物中重金属的赋存形态研究 总被引：1，自引：0，他引：1
用连续提取法对选自西北冰洋的32个表层沉积物进行分析,测定了Cr、Cu、Pb在全样中及其在P1-2、P3、P4、P5中的含量.结果表明随着离岸距离增加,水深加深,Cr、Cu、Pb含量呈增高的趋势.研究区陆架沉积物中Cr、Cu、Pb含量分别为60.66、14.77、16.65μg/g;深海沉积物中Cr、Cu、Pb的含量分别为80.40、41.70、25.62μg/g.元素赋存形态分析表明,Cr、Cu、Pb主要赋存在残渣态,残渣态中三元素的含量平均值分别为64.97、19.67、17.56μg/g,占元素总量的比例分别为93.58%、75.02%和83.76%.三元素在各赋存形态中的含量分布是:Cu为残渣态>有机质和硫化物态>铁锰氧化态>可交换及碳酸盐态;Pb和Cr则为残渣态>铁锰氧化物态>有机质硫化物态>可交换态及碳酸盐态.研究区重金属元素在不同赋存形态中的含量分布与北太平洋深海沉积物中类似. 相似文献