离子强度及pH对不同类型土壤中胶体释放的影响

采用实验室土柱纵向淋溶法,研究了离子强度及pH变化对常熟乌栅土原状、扰动土柱以及东北黑土、江西红壤扰动土柱土壤胶体释放的影响。结果表明离子强度变化对我国不同类型土壤胶体释放影响不同：淋洗液电解质为NaCl时,对于常熟乌栅土以及东北黑土,离子强度减小促进胶体的释放,反之抑制胶体的释放;对于江西红壤,离子强度变化对土壤胶体释放则不产生影响。淋洗液电解质为CaCl2条件下,土壤胶体的释放量低于淋洗液为NaCl,且离子强度变化对三种土壤胶体的释放均不产生明显影响。相同条件下,常熟乌栅土及东北黑土胶体释放量远远大于江西红壤,pH变化则对上述类型土壤胶体释放的影响不明显。研究结果有助于进一步阐明水化学条件的变化对我国不同类型土壤胶体释放的影响规律。     

不同阴离子溶液中怀俄明州蒙脱石的Na-Zn交换选择性

The effect of background anion on cation exchange reactions, such as Na-Ca and Na-Cu exchange reactions, on montmorillonites has been studied, but the results are not always clear and discrepancies exist in the literature. In this study, the exchange of zinc (Zn²⁺) for sodium (Na⁺) on Wyoming montmorillonite was investigated at 298°K using Cl^-, ClO₄^-, NO₃^-, OAc^-, and SO₄^2- solution media at a constant total metal charge concentration of 0.0200 molc L^-1. Results indicated that the clay CEC values were essential similar for Cl^-, ClO₄^-, NO₃^- and SO₄^2- solution media with an average CEC of 0.856 ± 0.008 molc kg^-1; in an OAc⁺ solution the clay CEC was much higher than that in other anion media. The specific adsorption of Zn (SAZn), as defined by the extraction of Zn using 0.05mol L^-1 Na₂-EDTA, was different in the various background solutions. The highest value for SAZn was 0.359 ± 0.0350molc kg^-1, which occurred in OAc-solution. There was essentially no difference in the total apparent adsorbed metals (the sum of adsorbed equivalents of Na and Zn per kilogram of clay, Q) among the various background solutions. The average Q for all anion media was 0.807 ± 0.011 mol_c kg^-1 and was independent of exchanger composition. Experimental results indicated that there were no significant monovalent cation complexes such as ZnCl⁺ or ZnNO₃⁺ that were adsorbed by montmorillonite. The Na-Zn exchange isotherms indicated that there was an adsorption preference for Zn over Na on Wyoming montmorillonite.     

柱状蒙脱石对环境污染物的吸附研究

Both inorganic and organic pillared montmorillonites were used to adsorb phenol.Batch kinetics and isoterm studies were carried out to evaluate the effect of equilibrium time and pH on adsorption of phenol by montmorillonites and re-adsorbing characteristics of pillared montmorillonites.The adsorption of phenol increased with increasing solution pH values.The elimination ratio of phenol from the solution by the absorption of organic modified pillared montmorillonte(OrPMt），reached equilibrium quickly after vi-brating for 5miuntes ,Meanwhile for organic montmorillonte(OrPMt),pillared montmorillonite(PMt) and montmorillonite(Mt),the time of reach phenol-absortion equilibrium were 20,30 and 90 minutes ,respectively,The adsorbing capacity of the pillaed montmorillonite modified with surfactant improved greatly. The phenol-adsorbing capacity of pillared montmorillonites mailnly depended on microporous struchure and surface component of the modified clays. Ater calcination at 500℃,the pillar structure and the basal spacing (1.83nm)were still stable .So the pillared montmorillonite could be recycled,and it was a potential material for adsorbing environmental pollutants.     

不同钝化机制矿物对土壤重金属的钝化效果及微生物响应

为探讨石灰石、蒙脱石两种不同钝化机制矿物施加对土壤重金属的钝化效果和土壤环境健康的影响,利用盆栽试验,通过常规测定方法和16S rRNA高通量测序手段,分析土壤酶活性和微生物群落结构的变化,并结合土壤重金属有效性、水稻富集系数和转运系数等指标,研究两种矿物施加后土壤的环境功能响应及其影响机制。结果表明:施加石灰石显著降低了土壤Cd、Cu、Pb、Zn的有效性,降低幅度依次为Zn(99.1%)Cd(91.4%)Cu(85.6%)Pb(46.1%),并显著降低了Cd、Zn的富集系数(43.4%～85.5%)和转运系数(Cd 62.5%、Zn 30.0%),而施加蒙脱石使土壤Pb的有效性降低幅度达19.5%,但其含量与对照差异不显著;施加石灰石显著提高了土壤过氧化氢酶和脲酶活性,均为对照(不施加钝化剂)的1.6倍,施加蒙脱石后土壤过氧化氢酶活性显著提高(为对照的1.4倍),但脲酶活性没有明显变化;施加蒙脱石对土壤微生物多样性和微生物群落结构影响较小,但施加石灰石后,土壤微生物多样性指数显著增加,且f_Gemmatimonadaceae、f_BIrii41和c_KD4-96等有益微生物属的丰度明显提高。研究表明,与通过吸附对重金属钝化的蒙脱石相比,石灰石通过提升土壤pH,不但能更有效地降低土壤中Cd、Cu、Pb、Zn等重金属的生物有效性,还能提升土壤酶活性和微生物的多样性,从而改善土壤健康状况,其中土壤pH、有效磷和有机质含量是影响微生物群落结构的关键因素。     

Radioactive contamination of plants in Japan covered with rain-out from H-bomb detonations in March-May 1954 at Bikini Atoll,Marshall Isls. (Part 1) Distribution of deposited radioactivity

Introduction

New H-bombs detonated from March-May 1954 at Bikini atoll not only gave unexpected disaster to crew on board No. 5 Fukuryu-Maru, a tunafishing boat which happened to be in the neighbourhood (43 miles away from) the dangerous area, but also brought a somewhat high radioactive fall-out all over Japan.     

含蒙脱土和多糖的保水剂对高羊茅品种可奇思种子萌发及生长的影响

采用正交实验法在室温下合成了含有天然产物蒙脱土（MMT）和羧甲基纤维素钠（CMC）的系列环境友好型保水剂,研究了不同保水剂组成和合成条件对高羊茅品种可奇思（简称可奇思）种子发芽及生长指标的影响规律。结果表明,试验合成的保水剂能显著提高可奇思的发芽能力和植株的生长指标,天然组分MMT和CMC含量对其发芽和植株生长影响显著。用性能最佳的保水剂处理可奇思种子,其发芽率、发芽指数、活力指数、总干重、总根长和总分蘖数分别比空白对照试样提高了61．6％、80．5％、125％、102％、67．6％和68．6％,比市售合成类保水剂对照试样提高了4．50倍、5．50倍、7．60倍、6．88倍、3．88倍和3．92倍,这对提高可奇思种子发芽能力和促进其植株生长具有重要意义,对该保水剂在可奇思种子发芽中的应用提供了试验依据,     

胶体作用下饱和土壤中Cd运移的数值模拟

通过室内土柱出流实验探讨了饱和壤砂土中Cd在SiO2胶体作用下的运移行为,并用对流-弥散方程(Convection-Dispersion Equation,CDE)对实验结果进行了数值模拟。结果表明,土壤中SiO2胶体的存在抑制了Cd的运移,土壤对Cd的吸附以动力学反应为主。耦合Freundlich等温吸附的单点非平衡模型(One Site Nonequilibrium Model,OSM)能较好地模拟Cd在壤砂土中的运移,模拟得到的吸附特性参数β较小,表明壤砂土吸附表面的不均一性较强。SiO2胶体的穿透时间较早,耦合沉淀-释放反应的CDE模型可以很好地描述SiO2胶体在壤砂土中的运移。胶体作用下的CDE模型成功地模拟了SiO2胶体存在时Cd的运移;同时,参数敏感性分析结果表明,胶体对Cd的吸附速率系数kamc、kaic越小,解吸速率系数kdmc、kdic越大,越有利于Cd的运移。     

纳米胶体金免疫标记技术在牛病检测中的研究和应用

作者综述了以胶体金免疫渗滤法和胶体金免疫层析法为代表的纳米胶体金免疫标记技术近年来在牛病检测方面的研究和应用进展,并分析和预测其应用前景,为该技术在牛病临床检测领域的进一步研究与应用提供参考。     

玉米赤霉烯酮污染日粮添加改性蒙脱石对断奶仔猪免疫指标的影响

【目的】研究1.0 mg•kg-1玉米赤霉烯酮（zearalenone,ZEA）污染日粮对断奶仔猪血液学、外周血T淋巴细胞亚群、血清免疫球蛋白和猪瘟抗体效价的影响,同时评价改性蒙脱石的脱毒效应。【方法】将36头试验仔猪按体重随机分为6个处理组（公母各半）,仔猪采用试验笼单独饲养;对照组饲喂基础日粮,试验1组在基础日粮的基础上添加1.0 g•kg-1改性蒙脱石（商品名：Calibrin-Z）,试验2组在基础日粮的基础上添加1.0 mg•kg-1 ZEA,试验3、4和5组在试验2组的基础上分别添加1.0、2.0和4.0 g•kg-1 Calibrin-Z。预饲期7 d,正式期22 d。【结果】与对照组相比,日粮添加1.0 mg•kg-1 ZEA组能显著降低断奶仔猪血小板、淋巴细胞比率、血红蛋白含量、外周血CD4+和CD8+的比例、血清IgG产量和21 d仔猪血清猪瘟抗体水平（P＜0.05）,1.0 mg•kg-1的ZEA处理组日粮添加2.0-4.0 g•kg-1 Calibrin-Z能够显著改善ZEA诱导的免疫毒性（P＜0.05）;且随日粮Calibrin-Z水平的增加,血小板、淋巴细胞比率、血红蛋白和血清IgG线性升高（P＜0.05）。【结论】1.0 mg•kg-1的ZEA足以诱导仔猪的免疫毒性,添加2.0-4.0 g•kg-1 Calibrin-Z具有显著的脱毒效应。     

土壤胶体在不同饱和度土壤介质中的释放与淋溶行为研究

采用饱和与非饱和填充土柱纵向淋溶研究方法,结合对流弥散模型方程（CDE）对穿透曲线的拟合计算,全面考察了土壤介质水饱和度、土壤水pH/离子强度、土壤孔隙水流速和土壤胶体颗粒大小对天然土壤胶体在实际土壤介质中释放、沉积迁移行为的影响。分别获取胶体扩散系数和阻滞因子值,定量说明实验中水化学、水动力学等条件的作用影响力。结果显示,介质不饱和条件不利于胶体的释放和淋溶;高pH和低离子强度条件对土壤胶体释放与迁移有利;淋溶过程的间断干扰,可以促使土壤胶体的增量淋溶释放;淋溶强度及胶体颗粒粒径大小,能够影响胶体穿透时间和穿透浓度峰值大小。