Effects of arsenic on seed germination and physiological activities in wheat seedlings

The effects of arsenic(As)were investigated on seed germination,root and shoot length and their biomass and some other factors to elucidate the toxicity of As.The results showed low concentrations of As(O-1 mg/kg)stimulated seed germination and the growth of root and shoot,however,these factors all decreased gradually at high concentrations of As(5-20 mg/kg).The contents Of O2-,MDA,soluble protein and peroxidase(POD)activity all increased with increasing As concentrations.Soluble sugar content,ascorbate peroxidase(APX),and superoxide dismutase(SOD)activities decreased at low concentrations of As,and increased at high concentrations of As.While acetylsalicylic acid(ASA)and chlorophyll contents,catalase(CAT)activity displayed increasing trend when the concentrations of As was lower than 1 mg/kg,and then decreasing trend.By polyacrylamide gel electrophoresis(PAGE).As induced the expression of POD isozymes of wheat seedlings.As induced the expression of CAT isozymes but inhibited the expression of SOD isozymes of wheat seedlings at concentrations lower than 1 mg/kg.However,As inhibited the expression of CAT isozymes but induced the expression of SOD isozymes at concentrations higher than 5 mg/kg.The results indicated As could exert harmfulness in the early development stage of wheat at inappropriate concentrations.     

阳离子聚丙烯酰胺复配钠基膨润土处理模拟苯酚废水

将阳离子聚丙烯酰胺与钠基膨润土进行复配,制备出复合吸附剂,并将其用于模拟苯酚废水的处理。采用XRD和FTIR技术对复配前后的钠基膨润土进行了表征。表征结果显示:阳离子聚丙烯酰胺附着在钠基膨润土的表面,对钠基膨润土的表面具有改性作用,使其由亲水性变为疏水性。实验结果表明:在阳离子聚丙烯酰胺与钠基膨润土的复配比例为200 mg/g、反应时间为40 min、复合吸附剂投加量为6 g/L、废水p H为11的最佳条件下,于25℃处理苯酚质量浓度为50 mg/L的模拟苯酚废水,苯酚去除率达89.5%。     

废水中聚丙烯酰胺在H-Beta分子筛上的吸附特性

将H-Beta用于处理含聚丙烯酰胺(PAM)的驱油废水,研究了PAM在H-Beta上的吸附动力学和热力学特征,并考察了吸附条件对吸附效果的影响.结果表明,吸附过程遵循准二级动力学模型;在低PAM初始浓度(100 mg·L-1)时,吸附表观活化能40 k J·mol-1,说明H-Beta对PAM的吸附以化学吸附为主;在高PAM初始浓度(200和500 mg·L-1)时,吸附活化能降低,吸附向物理吸附转变.吸附等温线在低平衡浓度区符合Langmuir模型,25、40和50℃时的单层饱和吸附量分别达到70.2、76.9和90.9 mg·g-1;在高平衡浓度区符合Freundlich模型,表现为多层吸附.吸附主要来自氢键作用,为自发的吸热过程.p H为2~4,吸附剂用量为5 g·L-1时,具有更优的吸附效果.真实废水中油和盐类的存在对PAM在H-Beta上的吸附未产生不利影响.     

应用聚丙烯酰胺的环境与生态行为研究

聚丙烯酰胺(PAM)在油田中的大量使用,其环境和生态行为及降解产物对环境的潜在危害,都亟待去研究。本文分析论述了其物理、化学性质及化学降解、机械降解、热降解、生物降解性,及影响其在土壤中的被吸附的因素和生态毒理学研究,提出有待进一步研究的课题为:PAM在油藏条件下的降解机理和降解速度;PAM及其衍生物在环境中的存在形式及其迁移转化的方式,在生物体内的存在形式及其在生物圈内的迁移转化等。     

浅谈混凝剂在气田水处理中的应用

在重庆气矿气田水处理中加入了聚合氯化铝和聚丙烯酰胺,其应结果表明,这两种絮凝剂配合使用的效果较好,能达到石油企业废水回注指标(pH值为6～9,SS小于30mg/L,石油类物质少于10mg/L)。分析了两者单独使用的处理结果,针对目前使用中存在的问题,指出应注意的事项,并对今后重庆气矿气田水处理运行中混凝剂的使用提出了建议。     

EVALUATION OF EROSION CONTROL PRODUCTS WITH AND WITHOUT ADDED POLYACRYLAMIDE1

ABSTRACT: Polyacrylamide (PAM) has been demonstrated to greatly reduce erosion in furrow irrigation, but much less is known about its effectiveness on the much steeper slopes typical of construction sites. The purpose of this study was to determine if anionic PAM would enhance erosion control either alone on bare soil or in combination with four types of ground covers commonly used for grass establishment: straw, straw erosion control blanket (ECB), wood fiber, and mechanically bonded fiber matrix (MBFM). Tests were conducted under natural rainfall and vegetation on a 4 percent slope (bare soil, straw, ECB, and MBFM) or using a rainfall simulator (bare soil, straw, wood fiber, MBFM) on either 10 percent or 20 percent slope on three different soil substrates. All ground cover treatments were evaluated with and without PAM applied in solution at 19 kg/ha. The straw, ECB, and MBFM significantly reduced runoff volume, average turbidity, and total sediment lost over five rainfall events on the vegetated plots. The addition of PAM to ground covers only occasionally had significant effects on runoff parameters but did significantly increase vegetative coverage overall. The rainfall simulator tests produced similar results after four events, with the straw, wood fiber, and MBFM all having significantly lower turbidity than the bare soil. The PAM significantly reduced turbidity for both the first and second events but did not consistently improve runoff quality after multiple rainfall events for any ground cover‐soil combinations tested. Separate tests of PAM applied before or after straw did not indicate a clear advantage of either approach, but runoff turbidity was often significantly reduced with PAM, especially at the 20 percent slope. Turbidity reductions were attributed to flocculation of eroded sediment.     

Cu2O@ZnO复合光催化剂对难生物降解有机物的光降解

通过改进的浸渍-还原-空气氧化法成功制备了Cu₂O@ZnO复合光催化剂,考察Cu₂O@ZnO对对硝基苯酚（PNP）和聚丙烯酰胺（PAM）2种不同化学结构污染物的光催化效果,同时探究了催化剂的稳定性和降解机制.结果表明,在模拟太阳光照射下,当铜锌物质的量比为0.15时,Cu₂O@ZnO复合光催化剂具有最佳的光催化降解性能,其中对硝基苯酚的光催化降解率为98.2%,聚丙烯酰胺光催化降解率为99.7%.基于X射线衍射（XRD）、X射线光电子能谱（XPS）、光致发光（PL）光谱、紫外-可见（UV-Vis）吸收光谱等表征手段可以推断,Cu₂O和ZnO形成Ⅱ型异质结,有效地抑制光生电子空穴对的复合.自由基捕获实验指出超氧自由基和空穴为主要活性物种,经过4次循环使用后光催化剂仍具有很高的光催化性能.     

市政污水厂脱水污泥对赤子爱胜蚓生长与繁殖的影响

在人工土壤条件下,通过添加5%、10%、15%、20%、25%、35%、50%(质量分数,以干重计)的市政污水厂脱水污泥(以下简称"污泥"),研究了添加污泥后对赤子爱胜蚓存活、生长和繁殖的影响,旨在为污泥农用对土壤生物的影响提供基础的参考数据.结果表明,随污泥掺入量增大,蚯蚓的死亡率先减小后增大,繁殖率逐渐减小;添加适量的污泥有利于蚯蚓生长,但没有显著的剂量-效应关系.蚯蚓的死亡和生长主要受重金属(尤其是Cu)的影响,繁殖能力受重金属和聚丙烯酰胺(PAM)共同影响.PAM的降解与蚯蚓的生存情况紧密相关.最终确定污泥的掺入量不宜超过20%.     

PAC和PAM复合混凝剂处理垃圾渗滤液的试验研究

确定PAC和PAM复合混凝剂对垃圾渗滤液进行处理的最佳工艺条件.向垃圾渗滤液中投加混凝药剂,以COD和浊度作为考察指标,根据单因素和正交试验确定其最佳的工艺条件.试验研究表明,在室温条件下,pH=5.5,PAC的投加量为1 000 mg/L、PAM投加量为15mg/L、混凝反应1 min(快速搅拌结束后)投加PAM,对...     

β-环糊精与聚丙烯酰胺的接枝化合物及其对水中污染物的絮凝作用

合成了聚丙烯酰胺与环糊精的接枝化合物，研究了该接枝化合物对模拟水样中污染物的去除能力。试验结果表明，β-环糊精和聚丙烯酰胺的接枝化合物与聚丙烯酰胺相比，对重金属离子Cu^2 、Zn^2 、Cd^2 、Pb^2 ，苯酚和苯胺的去除能力皆有一定的提高。