Precipitation interaction mechanism of humic acid with rare earth elements.

对腐殖酸与三价稀土元素在水溶液中的结合作用进行实验研究,在宽浓度范围内探讨两者之间的络合与沉淀反应机制,考察溶液体系稳定性及其离子强度和pH值的影响.结果表明腐殖酸与稀土离子形成的配位络合物是沉淀产生的主要原因,共存体系的稳定性明显受到离子强度和pH值影响.腐殖酸和稀土元素通过共沉淀从溶液中去除,在作用机制上表现为离子交换、配位络合和共沉淀等多种形式.Interactions of humic acid with trivalent rare earth ions (REE~(3+)) in solution were examined to study the mechanisms of complexation and precipitation reactions, and the effects of ionic strength and pH on the stability of solution systems were investigated. The experimental results indicated that the formation of complexation products of humic acid with REE~(3+) is the main cause of precipitation, and the stability of coexisting solution systems is affected evidently by the ionic strength and pH. The humic acid and rare earth elements can be removed from the solution by the coprecipitation in which the ion exchange, complexation and coprecipitation are the most important interaction mechanism.教育部优秀年轻教师基金资助项目(1999)

Adsorption mechanism of rare earth elements and humic acids in the system of iron oxyhydroxide

实验考察稀土元素(La3+、Ce3+、Ho3+、Yb3+)在水合氧化铁表面的吸附动力学过程,对比研究腐殖酸对吸附机制的影响.当腐殖酸与稀土元素共存时,腐殖酸通过化学吸附优先占据氧化铁表面的吸附点位,颗粒物表面特性因覆盖有机膜而得到修饰.初期的动力学过程主要表现为腐殖酸的竞争吸附,随后转变为吸附态腐殖酸对稀土元素的表面结合.轻稀土因较强的结合能力而比重稀土易于被吸附去除,这与天然水体中发生的稀土元素分异现象保持一致.Kinetics of rare earth elements(La~(3+),Ce~(3+),Ho~(3+),Yb~(3+)) adsorption to the iron oxyhydroxide were investigated,and the effects of humic acid on adsorption mechanism were revealed.Coexisting humic acid with rare earth elements(REEs),the surface sites of iron oxyhydroxide might be occupied preeminently by the humic acid through the chemical adsorption,and the characteristics of the solids are decorated by covering the organic membrane.The adsorption kinetics of REEs initially shows the competitive adsorption with humic acid,and then is the surface binding with the adsorbed humic acid.The LREEs tend to be adsorbed on the solids and removed from the liquid due to their stronger binding ability with humic acid than the HREEs,which is consistent with the fractionation of the REEs taking place in the natural waters.国家教育部资助优秀青年教师项目(1999

区域循环经济数学模型建立及应用研究

在区域层面上分析社会经济系统内的物质流特征,提出衡量区域经济循环程度的标志性指标,并以制定区域循环经济发展规划为目标,建立了区域循环经济多目标规划数学模型。以江南某新兴工业城市为例,采用该市历史统计数据,开展区域循环经济发展规划的实证研究。计算结果表明,多目标线性规划模型是解决区域循环经济问题的有效方法,在参数选取和决策流运算求解方面具有一定的可操作性,对科学制定区域循环经济发展战略具有参考应用价值

海洋工程环境影响评价实践中存在的问题

在海洋工程环境影响评价工作中遇到许多实际困难,本文列举了对海洋功能区划、评价等级的划分、环境容量、现状监测、污染防治措施、环境事故风险评价等方面存在的困惑之处,并提出自己的一些见解

区域循环经济指标体系研究及案例分析

以循环经济理论为基础,依据循环经济"3R"原则构建区域循环经济普遍化指标体系,通过对具体指标的主成分和独立性分析,构建具有代表性和可操作性的区域循环经济指标体系,运用层次分析法测算指标权重。以石狮为例,对区域循环经济发展水平与趋势进行案例分析,结果表明该市循环经济核心指标指数和综合发展指数均较低,循环经济总体发展水平处于起步阶段。国家自然科学基金资助项目(70473077

Characteristics and assessment of environmental quality in seawater and sediment of Yacheng Bay,Fujian

于2005年10月首次调查了福建牙城湾海域水体及沉积物的环境质量。结果表明,海水中主要超标污染物为PO4-P和d In,其含量范围分别为0.029--0.037 Mg/l和0.270--0.510 Mg/l,其它指标均符合二类海水水质标准。沉积物中各项指标基本达到《海洋沉积物质量》的一类标准,其中Hg、Pb、Cu和Cd等四种重金属的平均含量分别为0.091x10-6、39.7x10-6、29.3x10-6和0.118x10-6,有机物和硫化物的平均含量分别为0.941x10-2和207x10-6。湾水水体已达到富营养状态,且n为限制因子。此外,对沉积物中重金属及其他环境因子间的相关性进行了分析。The concentrations of the major environmental items in surface seawater and sediment are reported for the first time in Yacheng Bay in Fujian Province in Oct.2005.The major pollutants in seawater are DRP and DIN,and their concentrations are 0.029～0.037 mg/L and 0.270～0.510 mg/L,respectively.The contents of other environmental items in seawater are within the Second Class Standard of Seawater Quality.Most of the items in surface sediments are below the values of First-class Standard for Marine Sediments Quality.The average concentrations of Hg,Pb,Cu,Cd in surface sediments are 0.091×10-6、39.7×10-6、29.3×10-6 and 0.118×10-6,respectively.The organic matter and sulfide are 0.941×10-2 and 207×10-6,respectively.It is found that the quality in seawater in Yacheng Gulf was in eutrophication condition using the way of index E,while the limit factor is N.What's more,the correlations among some heavy metals and other environmental items were also analyzed.国家自然科学基金(40306012);福建省重点科技项目(2005Y021);福建省海洋与渔业局科技项目(1020-K53011;0051-K37011

Study on the Binding Sites of Humic Acids with Rare Earth Elements and Its Characterization

采用红外光谱(FTIR)与核磁共振波谱(1H NMR和13C NMR)技术,对来自森林土壤和湖泊沉积物的两种腐殖酸及其与三价稀土离子(RE3+)沉淀反应的产物进行对比研究.结果表明,腐殖酸结构中活性官能团特征以及它的拥有量因腐殖化程度不同而存在较大差异.腐殖酸与RE3+沉淀反应产物在性质上属于一种有机弱酸盐,羧基-COOH和酚羟基-OH为主要结合点位,结合反应过程中它们的质子被RE3+交换出来.Two types of humic acids taken from forest soil and lake sediment,and their precipitation reaction products with the trivalent rare earth elements are identified comparatively by FTIR,~1H NMR and ~(13)C NMR spectroscopy.The FTIR and NMR spectra indicate that the structural framework of two humic acids are similar principally due to their same origin,but there is great difference in the structural characteristics and functional groups amount of humic acids because of their different humification degree.Forest soil humic acid(FHA) has more Ar-COOH with strong binding strength than lake sediment humic acid(SHA),which has more Ph-OH with weak binding strength due to its high humification degree.The explicit evidences of humic acids binding with trivalent rare earth elements are found from FTIR and NMR spectroscopy,which the Ar-COOH and Ph-OH are the main binding sites of humic acids with RE~(3+).The precipitation reaction products of humic acids with RE~(3+) belong to a kind of undissolved organic weak acid salts,which are similar to the binding reaction mechanism of weak acid with metal ions.In the reaction procedure of humic acids with RE~(3+),the results of pH monitoring of the solutions demonstrate that the protons of ArCOOH and Ph-OH can be exchanged out by RE~(3+).教育部优秀青年教师基金资

Determination of 1-Hydroxyl Pyrene in Tap Water and Human Urine by Enhanced Synchronous Fluorescence Spectrometry with β-Cyclodextrin and n-Propyl Alcohol

使用正丙醇这一小分子脂肪醇,进一步促进β-环糊精有序介质对1-羟基芘的荧光增强作用,基于此,利用同步荧光法测定水样中的1-羟基芘,检测限达到2.5×10-11m ol/L,相对标准偏差为3.8%(n=5),运用该方法测定了自来水与人尿样品中的1-羟基芘,结果满意。Joint use of β-Cyclodextrin and n-propyl alcohol can enhance synchronous fluorescent intensity of 1-hyroxyl pyrene(1-HP) greatly.Based on this phenomenon,experiments were carried out,a new method for the determination of 1-HP established by enhanced Synchronous Fluorescence Spectrometry.The limitation of determination of this method was 2.5×10-11 mol/L,RSD=3.8%(n=5).Tap water and human urine samples were determined by this method,and satisfying data were gained

Distribution and Potential Ecological Risk Evaluation of Heavy Metals in the Surface Sediments From the Jiulongjiang River Estuary

对九龙江口表层沉积物中的TOC,Cu,Pb,Cd,Cr,Hg,AS的含量进行了分析,TOC,Cu,Cd,Hg和AS的质量分数均符合一类海洋沉积物质量标准;Pb和Cd在个别站位超标。相关性分析表明,九龙江口表层沉积物中大多数重金属呈现相近的来源特征,有机质是影响沉积物中重金属分布的重要因素。采用潜在生态风险指数法对九龙江口表层沉积物重金属污染的潜在生态风险进行了评价,结果表明,九龙江口存在一定程度的生态风险,重金属的生态风险依次为Cd>Hg>AS>Pb>Cu>Cr,除Cd达到重的生态风险外,其余元素均为低生态风险。Analyses were made of the contents of TOC,Cu,Pb,Cd,Cr,Hg and As in the surface sediments from the Jiulongjiang River Estuary.The contents of TOC,Cu,Cr,Hg and As are in accordance with the marine sediment quality standard I and those of Pb and Cd are beyond of the standard at some stations.The correlation analysis indicates that most of the heavy metals in the surface sediments of the Jiulongjiang River Estuary are similar in sources and organic metter is an important factor that influences the distributions of heavy metals in the surface sediments.The potential ecological risk caused by the pollution of heavy metals in the surface sediments is evaluated by means of serious ecological risk index.The results indicate that the potential ecological risk of the heavy metals in the surface sediments of the Jiulongjiang River Estuary is in the order of Cd>Hg>As>Pb>Cu>Cr.of them,Cd is the most hazardous element and others belong to low ecological risk elements.国家自然科学基金——区域循环经济体系及其产业结构的生态重组研究(70473077