Effects of <Emphasis Type="Italic">Urechis unicinctus</Emphasis> juveniles on chemical characteristics of organically contaminated coastal sediment

Biological activities of marine benthos such as burrowing and feeding may change sediment characteristics. We conducted three experiments to examine the potential of using juveniles of a spoon worm Urechis unicinctus to improve the quality of organically contaminated coastal sediment. Sediment samples were collected from a site that was heavily contaminated with organic matter (Seonso) and two sites that were clean (Myo-do, Dolsan-do). Urechis juveniles, obtained by artificial fertilization and cultured in the laboratory, were introduced to the sediment (weight 3 kg, depth 10 cm) at a density of 500 individuals per aquarium (length 50 cm, width 35 cm, height 30 cm) (Experiment 1), or at densities ranging from 100 to 900 individuals per beaker (Experiment 2). To examine how sediment contamination can be modified by the effects of Urechis, 500 individuals (per aquarium) were exposed to the Seonso contaminated sediment that had been mixed with 0–100% clean sand (Experiment 3). Each experiment lasted two months and sediment samples were collected every 15 d to determine the several indexes of sediment quality, which included acid volatile sulfide (AVS), chemical oxygen demand (COD) and total ignition loss (TIL). In Experiment 1, the existence of Urechis did not result in significant changes in quality indexes in the sediments collected from Myo-do, Dolsan-do. However, AVS, COD and TIL of the Seonso sediment all decreased significantly after co-incubation with Urechis juveniles for 30 to 45 d. Experiment 2 showed that a density of at least 300 juveniles per beaker was necessary to significantly reduce all three quality indexes, and the magnitude of reduction was positively correlated with juvenile density. Experiment 3 revealed that Urechis juveniles were effective in reducing the AVS, COD and TIL of the Seonso sediment that had been mixed with 60%, 80%, and 80% of clean sand, respectively. The results of the present study therefore indicated that juveniles of this spoon worm have the potential to be used to improve the quality of organically contaminated sediment in coastal waters.     

黄土-古土壤沉积物中酸溶相硼的分离及其同位素测定

用０．５ｍｏｌ／ＬＨＣｌ提取黄土、古土壤中的酸溶相成分,并用混合树脂法和硼特效树脂法两方法叠加以硼进行分离和纯化,Ｃｓ２ＢＯ２＾＋法测同位素比值。结果表明,虽然混合树脂法和硼特效脂法都是较成熟的方法,但用来处理杂质离子含量相对高而硼含量低的样品深液并不成功。两种方法叠加处理后达到理想的效果,重复处理黄土－古土壤样品的精度（２ＲＳＤ）在０．４‰～０．４‰之间,这与标样（ＮＩＳＴ ＳＲＭ９５１）水平（     

闪锌矿精矿的氧压酸浸提取研究

对锌精矿的氧压酸浸条件进行了研究,实验表明：在压力为1.7MPa、温度为140℃～155℃条件下加热1小时,浸出终液硫酸酸度＞1.0mol/L时,锌精矿中锌及稀散元素的浸出率分别为：98.76%（Zn）、96.42%（Ga）、89.03%（Ge）、97.35%（In）、91.30%（T1）.结果表明,该方法具有较高的浸出率,并能消除对环境的污染,具有一定的应用前景.     

大孔膦酸树脂吸附银的行为与机理

研究了大孔膦酸树脂对银的吸附行为、机理及洗脱条件。结果发现:大孔膦酸树脂对银离子的吸附在pH=4.10的HAc-NaAc介质中最佳,静态饱和吸附容量为178mg/g,用5%硫脲-0.5mol/L盐酸溶液能定量洗脱;测得298K下的吸附速率常数k298K=8.89×10-5s-1。吸附机理研究表明,大孔膦酸树脂功能基与Ag(Ⅰ)可能发生了配位键合,配位比为3∶1。     

金川铜镍矿山尾矿砂酸溶性实验研究

为研究金川铜镍矿山酸性废水溶解尾矿砂实现综合治理废液与废固的可能性,进行了尾矿砂在硫酸中的溶解实验。结果表明,尾矿砂在硫酸浓度大于3mol/L、温度保持90℃以上并在液固比6.0下强力搅拌,能够较好地溶解于硫酸中,生成无定形二氧化硅;300℃的马弗炉焙烧4h有助于尾矿砂中绿泥石的溶解,对透闪石的溶解影响不大。尾矿砂中橄榄石、蛇纹石和透辉石较容易被硫酸溶解,透闪石、斜长石则比较难溶解,这与尾矿砂中矿物性质有密切关系。     

海底沉积物中不同形式烃类气体的地球化学意义

顶空气法和酸解烃法将东沙群岛海域海底浅表层沉积物中不同形式的烃类气体释放出来,通过分析两类气体在沉积物中的含量及其甲烷碳同位素,发现两类气体的成因和来源不同。笔者认为,相对而言,吸附气(包裹气)反映的是一种更为早期的信息,而游离气(溶解气)则更具有“现代性”。笔者进一步认为,两类气体的不同形成过程,对于天然气水合物调查具有不同的意义,其中游离气(溶解气)具有直接的指示意义,而吸附气(包裹气)可能指示成岩时沉积物中的空间信息。     

高岭土/胡敏酸复合体对重金属离子吸附解吸实验研究

本文利用高岭土对胡敏酸吸附形成稳定的有机一无机络合物,研究了高岭土／胡敏酸复合体对Cu^2＋、Cd^2＋和Cr^2＋的吸附。结果表明,胡敏酸对高岭土改性后能提高上述三种重金属离子的吸附性能,高岭土／胡敏酸复合体对三种重金属离子的吸附量都随pH值的升高而增加,随离子强度的增加而减小。本文还研究了高岭土／胡敏酸复合体对上述三种重金属离子的吸附动力学,发现吸附过程可用Elovich方程和一级动力学方程进行较好的拟合。