虾蛄壳生物炭吸附Pb^(2+)的特性及机理研究

以废弃虾蛄壳为原料制备生物炭(MSSB),利用SEM、BET、FTIR和XRD等技术对MSSB进行了表征.探讨了吸附时间、Pb^(2+)浓度、初始pH、MSSB添加量、共存离子以及共存污染物等对MSSB吸附Pb^(2+)的影响.利用吸附动力学模型与等温吸附模型以及测定吸附前后滤液中离子含量的变化探究吸附机理.MSSB对Pb^(2+)的吸附动力学更符合拟二级动力学模型,吸附等温线则更符合Langmuir模型,根据Langmuir模型计算得出MSSB对Pb^(2+)的最大吸附容量为1467.6 mg·g^(-1).吸附以化学吸附为主,具体涉及孔隙作用、沉淀作用、络合作用、静电吸引、离子交换等多重作用机制.MSSB有潜力用于高效去除水体中的Pb^(2+).

Effect of bionic mantis shrimp groove volute on vortex pump pressure pulsation

In order to reduce pressure pulsation of vortex pumps,the mantis shrimp was chosen as biological prototype and a bionic engineering model was developed from its abdominal segment grooves.Bionic mantis shrimp groove volute vortex pump models with different numbers of grooves were developed,and numerical simulation methods were used to calculate the models to study the effects of the volute grooves on the pressure pulsation of a vortex pump.The results show that a bionic groove volute could effectively improve the pressure pulsation of a vortex pump outlet,and reduce the pressure pulsation around the pump’s tongue and other internal points.The pressure pulsation under different conditions is impacted by shaft frequency and blade frequency.The bionic groove structure has little effect on the external characteristics of the pump,but could improve the static pressure,velocity distribution,and vortex structure of the flow field.Additionally,pressure pulsation of the whole vortex pump is reduced.

Morphometric, Reproductive Parameters and Seasonal Variations in Fatty Acid Composition of the Mantis Shrimp Squilla mantis （Crustacea： Stomatopoda） in the Gulf of Gabes （Tunisia）

The growth, reproductive properties and the variations in total lipids and fatty acids in the gonads and muscle tissue of the mantis shrimp Squilla mantis （Crustacea： Stomatopoda） caught from the gulf of Gabes in Tunisia were studied by sampling carried out between Jan. 2005 and Dec. 2006 to elucidate the importance of these components during sexual maturation. A total of 16,569 specimens were examined. The sex of this species was determined macroscopically and the proportion of females （47.07%） was significantly lower than that of males （52.93%） with a ratio of 1 ：l. 12 （male^female）. The mean total lengths （TL） of the male and female individuals were 142.02 ~： 22.76 mm and 141.45 ＋ 24.37 mm, respectively. Length-weight （TL-W） relationship was estimated as W = 7 ~ l06 TL3 o644 for females and W = 4 ~ 10＂6 TL320o7 for males, being altometrically positive for both sexes. The reproductive season, evaluated from the gonado-somatic index （GS1）, extended from Dec. to July, with a peak in Feb.. The smallest mature female was 93 mm total length. Fifty percent of the females were mature at 147.19 mm total length. The levels of lipid displayed pronounced seasonal fluctuations with the highest value in Feb. and the lowest value in Oct.. Major fatty acids in both gonads and muscle tissue （female and male） were C 14：0, C 16：0, C 18：0, C 18： I n-9, C 18：2n-6, C 18：3n-3, C20：4n-6, C20：5n-3 and C22：6n-3. Significant increases in the levels of saturated and poly-unsaturated fatty acids were observed in gonads. The levels of n-3 poly-unsaturated fatty acids （PUFA）, particularly C20：5n-3, decreased in gonads as ovarian development proceeded. Docosahexaenoic acid （DHA）, linoleic acid （LA） and eicosapentaenoic acid （EPA） were the most abundant polyunsaturated fatty acids （PUFAs） in the muscle tissue for both male and female. The highest percentages for EPA and DHA were found in winter and summer season for Squilla mantis in the Gulf of Gabes. The n-3/n-6 ratio fatty acids ratio in Squilla mantis can be significantly influenced by spawning and season. It was conchtded that the mantis shrimp is a healthy item in the human diet during the winter and summer period when balanced n-3/n-6 ratios and EPA and DHA levels are considered.