HPAM和PACS对钠型蒙脱土悬浮体的混合絮凝作用

用聚丙烯酸酰胺(PAM)、增聚羟基氯化铝(PACS)和水解聚丙烯酰胺(HPAM)等高聚物作絮凝剂研究其各自对土壤悬浮体的絮凝效果及絮凝机理已有报道,本文研究了HPAM和PACS混合时对钠型蒙脱土悬浮体的絮凝作用,结果表明,混合使用比单独使用时效果显著。     

高强度PAM/PVP半互穿网络凝胶制备及力学性能

以过硫酸铵为引发剂通过一步溶液聚合制备了由化学交联的聚丙烯酰胺(PAM)与聚乙烯吡咯烷酮(PVP)贯穿形成的PAM/PVP半互穿网络(semi-IPN)凝胶,着重研究了凝胶的机械性能。红外光谱、热重分析及拉伸实验分析可知PAM与PVP之间存在氢键作用。拉伸实验表明:在PAM中引入PVP,凝胶拉伸强度明显提高,m(PVP)/m(AM)=7.51%时制备的PAM/PVP semi-IPN凝胶拉伸强度比单纯化学交联的PAM增大64.67%;当AM=6mol/L,n(MBA)/n(AM)=1.67×10-4,m(PVP)/m(AM)=7.51%时,制备的凝胶机械性能较好,拉伸强度达到1.84MPa,断裂伸长率可达3322%;随着含水率增加,凝胶拉伸强度及断裂伸长率均有所降低。     

基于PAM/CS/MoS2复合水凝胶的QCM湿度传感器制备及应用

通过自由基聚合的方法，将二硫化钼(MoS₂)引入聚丙烯酰胺/壳聚糖(PAM/CS)水凝胶体系，制得互穿网络结构的PAM/CS/MoS₂复合高分子水凝胶。利用傅里叶变换红外光谱、拉曼光谱、扫描电子显微镜、激光扫描共聚焦显微镜对水凝胶的组分和形貌进行分析。利用万能试验机和接触角测量仪对水凝胶的力学性能和亲水性能进行测试，最后用石英晶体微天平(QCM)探究了该复合水凝胶薄膜在湿度传感领域的应用。结果表明，PAM/CS/MoS₂-0.4(MoS₂在体系中的质量为0.4 mg)复合水凝胶具有最大的压缩应力(584.6 kPa)与最大的压缩应变(83.8%);MoS₂的引入，增强了复合水凝胶的亲水性；随着环境相对湿度从11%增加到95%，基于PAM/CS/MoS₂复合水凝胶的QCM湿度传感器的响应频率最大可达2 642 Hz，相对湿度变化1%的灵敏度为31.45 Hz，有望应用于湿度传感领域。     

高分子模板调控不同形貌氧化亚铜的仿生合成

采用聚丙烯酰胺(PAM)为软模板,在CuSO4、Na2SO3体系中调控合成了片状、海胆状、一维线、针状聚集体氧化亚铜晶体。研究了不同浓度Cu2+、不同PAM含量及不同温度对晶体生长的影响。结果表明,PAM促使氧化亚铜异相成核,氧化亚铜形貌随PAM质量分数的变化而变化:当c(Cu2+)=0.5mol.L-1时,PAM质量分数为3.0%(常温引入体系),产物主要为片状晶体;PAM质量分数为1.0%、3.0%时(高温引入体系),分别获得一维线状、海胆状晶体;当Cu2+浓度为0.1 mol.L-1时,体系中高温引入质量分数3.0%的PAM,得到片层状晶体;当Cu2+浓度为0.3、0.4 mol.L-1时,得到针状聚集体氧化亚铜晶体。分别用X射线粉末衍射、冷场发射扫描电子显微镜和激光粒度仪对所制备的产品进行了表征。     

纳米二氧化钛增强聚丙烯酰胺/聚乙烯亚胺凝胶的制备及其性能

聚乙烯亚胺（PEI）是一种环境友好型交联剂，但与聚丙烯酰胺(PAM)形成的凝胶体系强度较弱，而纳米二氧化钛是一种非常有效的结构增强剂。制备了纳米二氧化钛增强的PAM/PEI凝胶，其结构经XRD和TG表征。结果表明：纳米二氧化钛对PAM/PEI凝胶有良好的增强作用。在90 ℃下，可使凝胶的成胶时间从7 h缩短至3 h，凝胶强度由F提高至H。     

Fe(II)(EDTA)螯合物/UV催化臭氧工艺降解PAM溶液研究

研究采用Fe(II)(EDTA)螯合物/UV催化臭氧降解聚丙烯酰胺(PAM)溶液。考察Fe(II)(EDTA)螯合物/UV催化臭氧法对PAM溶液粘度、PAM去除率和可生化性的影响。研究表面活性剂对Fe(II)(EDTA)螯合物/UV催化臭氧工艺降低PAM粘度的影响,并探讨草酸对该工艺降解PAM溶液影响规律。研究结果表明,Fe(II)(EDTA)螯合物/UV催化臭氧法对PAM溶液降解效能良好,在15min内,PAM溶液粘度的可以降低57%,在120min后,PAM去除率可达75%,B/C从0.121提升到0.423。表面活性剂对Fe(II)(EDTA)螯合物/UV催化臭氧工艺降低PAM溶液粘度影响较小。草酸不利于Fe(II)(EDTA)/UV催化臭氧工艺去除PAM和降低PAM溶液粘度,这是因为草酸造成的酸性环境抑制了臭氧在水中的分解作用,从而导致草酸/Fe(II)(EDTA)/O3体系中PAM溶液的降粘效果和去除率低于Fe(II)(EDTA)/O3体系。     

聚丙烯酰胺/层状无机物纳米复合材料研究进展

聚丙烯酰胺(PAM)/层状无机物纳米复合材料相比于纯PAM具有更好的力学性能、超吸水性能、热稳定性能和气体阻隔性能等,是一种性能优异并在采油、农业和卫生学等领域有着广泛应用前景的新型聚合物基纳米复合材料。本文对近年来聚丙烯酰胺/层状无机物纳米复合材料的研究进展进行了综述。首先重点介绍了层状双氢氧化物(LDHs)在有机溶剂和水中剥离分散方面的研究进展,接着综述了PAM/LDH和PAM/粘土纳米复合材料的制备与结构表征,最后阐述了PAM/层状无机物纳米复合材料的流变性能、力学性能和超吸水性能等。     

阳离子化聚丙烯酰胺絮凝剂阳离子化度分析方法的探讨

聚丙烯酰胺絮凝剂(以下简称PAM)是最近十多年来发展起来的一种高效高分子有机沉降剂。在PAM基础上近年来又发展了阳离子型和阴离子型RAM。这些沉降剂在石油、化工、冶金、环保等部门得到了广泛应用。有关阳离子化PAM阳离子化度分析方法的报导很少见,几年前北京矿冶研究院等单位研制成功一种适用于高浓度硫酸矿浆的二乙胺型阳离子化PAM,但缺乏分析方法,他们只     

聚丙烯酰胺纳米复合水凝胶研究进展

传统化学交联的聚丙烯酰胺(PAM)水凝胶由于力学性能较弱,其应用范围受到很大限制。与之相比,采用纳米复合技术制备的PAM纳米复合(NC)水凝胶,不仅大幅提高了力学性能,而且在溶胀率等方面也有明显的提高。本文结合该领域近年来的研究进展,将PAM NC水凝胶分为纯物理交联和化学物理交联相结合两类,重点讨论了NC水凝胶在力学性能方面的研究结果,对溶胀率等其它方面的性能也进行了综合论述。     

聚丙烯酰胺结构与水溶液粘度保持率

聚丙烯酰胺衍生物(PAM)是高温高矿化度油藏的关键性助剂之一,为适应油藏高温环境,PAM不仅需要具有优异的热稳定性,还应在温度升高时具有较高的粘度保持率。与耐温抗盐单体共聚显著改善了PAM的热稳定性,已有许多文章总结了这一领域的进展。相对而言,关于PAM水溶液在高温时粘度保持率的报道较少。本文从聚合物分子构造以及其在水溶液中的聚集态结构出发,总结了PAM水溶液粘度保持率与结构的关系。主要包括在线性主链上引入支化侧链来提高聚合物分子链刚性,以及利用超分子相互作用形成物理交联网络改变PAM在水溶液中的聚集态结构。此外,展望了耐温抗盐PAM的发展趋势。     

Thermal and microbial degradation of alginate-based superabsorbent polymer

In this study, an alginate-based superabsorbent polymer (SAP), alginate-graft-poly[acrylamide-co-(itaconic acid)-g-(acrylic acid)] or Alg-g-P(AM-co-IA-g-AA), was prepared to examine its thermal and microbial degradation properties through Thermogravimetric Analysis (TGA), and soil supernatant test (with and without added nutrient) and soil burial test, respectively. The TGA thermogram of the SAP showed three degradation steps. The first degradation step was due to the thermal degradation of alginate and decomposition of the functional groups of PAM, PIA and PAA; whereas the second degradation step occurred as a result of the decomposition of PAM, PAA and PIA chains. Further decomposition of PIA contributed to the third degradation step. Among all the soil samples [tropical forest soil (TF), former tin mine lake soil (TM), peanut farm soil (PF), indigenous microorganism soil from an organic vegetable farm (OF), and oil palm plantation soil (OP)] tested, OF soil degraded the polymer sample most effectively, with the highest weight loss of 82.6% (with added nutrient) and 82.8% (without added nutrient) in soil supernatant tests, and 63.5% in soil burial test. Morphological observation under an Illuminated Stereo Microscope showed some holes and weak topographical spots on the surface of the polymer material after it had been incubated in OF solution for 40 days. Meanwhile, the intrinsic viscosities, [η], of NaAlg and the Alg-based SAP solutions were 2.62 and 2.75 respectively.     

土壤中砷形态分析研究进展

本文评述了近年来国内外土壤中砷形态分析的主要研究方法,包括联用分析法、分级提取法和同步辐射X-射线线吸收光谱法。联用分析法包括气相色谱联用法、毛细管电泳联用法和高效液相色谱联用法。重点介绍了目前应用范围较广的高效液相色谱-等离子体质谱(HPLC-ICP-MS)联用法和高效液相色谱-氢化物发生-原子荧光光谱(HPLC-HG-AFS)联用法。同步辐射X-射线线吸收光谱法近几年发展迅速,是最具发展潜力的形态分析方法。     

土壤在环境污染治理中的研究与应用

本文综述了土壤在环境处理中应用研究的进展。介绍土壤作为环境污染物处理材料在吸附、絮凝、催化等功能应用方面的研究现状;重点阐述土壤作为催化功能材料的高级氧化体系对污染物的降解;并就该领域研究的发展进行了探讨,引用文献49篇。     

Isoelectric focusing in soil science

Applications of isoelectric focusing (IEF) in soil science are illustrated. The materials studied, i. e. humic substances and organic fertilisers, and their behaviour when subjected to IEF are briefly described. Preliminary studies carried out on soil indicate a relation between the isoelectric point and molecular weight, and a connection with humification has been hypothesised; therefore, assessment of soil conditions could be an application of IEF. Another application is evaluation of the stabilisation of organic fertilisers. Finally, IEF can be used to distinguish different organic matrices, as such and in mixtures with mineral fertilisers.     

Mussel-Inspired Adhesive,Antibacterial, and Stretchable Composite Hydrogel for Wound Dressing

Hydrogels have attracted extensive attention in the field of biomedicine because of their similar structure to extracellular matrix (ECM) and good biocompatibility. However, the adhesiveness, mechanical properties, and antibacterial properties of conventional hydrogels are not satisfactory. In this study, multifunctional chitosan/polydopamine/polyacrylamide (CS/PDA/PAM) hydrogels are prepared through a nature-inspired strategy. The catechol group of polydopamine (PDA) component endows CS/PDA/PAM hydrogels with tissue adhesion and self-healing properties. The introduction of chitosan (CS) not only greatly improves antibacterial ability, but also enhances the mechanical properties of CS/PDA/PAM hydrogels. Skin wound healing experiments show that CS/PDA/PAM hydrogels could accelerate skin tissue regeneration and promote wound healing. Therefore, CS/PDA/PAM hydrogels have great potential in the application of new wound dressings.     

Environmental monitoring approaches used during bioremediation of soils contaminated with hazardous explosive chemicals

Defense sites are contaminated with explosives, which are released during manufacturing, firing, testing and training operations; loading, assembly and packing activities; and demilitarization operations. Explosive chemicals are hazardous in nature. Contamination of the soil and the underlying groundwater by explosives pose serious threat to human and animal health and the eco-system. Bioremediation is an eco-friendly technology as it exploits nature’s own agents- the microbes in degrading the contaminant of interest. This waste treatment technology has been extensively studied for degrading the explosive pollutant. Environmental monitoring, a process of systematic collection of data and analysis is essential in performance evaluation of any waste treatment system. This paper gives a comprehensive overview on the environmental monitoring approaches used during bioremediation of explosives contaminated soil. Biogeochemical factors viz., presence and survivability of microbes, bioavailability of the contaminant, pH, temperature, moisture content, redox conditions, presence/addition of substrate and nutrients and presence of intermediates/co-contaminants in the soil environment that are reported to affect the bioremediation of explosives are highlighted. Details on physical, chemical and biological parameters monitored during bioremediation are included. Advancements in instrumental techniques are evolving rapidly and its application in bioremediation approaches promise an enhanced understanding of the mineralization of explosive in the soil environment. Recent developments in application of advanced analytical instrumentation techniques, future research insights with recommendations, which will illuminate the selection of appropriate monitoring tool for evaluating bioremediation are also summarized.     

Laser-induced breakdown spectroscopy (LIBS) to measure quantitatively soil carbon with emphasis on soil organic carbon. A review

Soil organic carbon (OC) measurement is a crucial factor for quantifying soil C pools and inventories and monitoring the inherent temporal and spatial heterogeneity and changes of soil OC content. These are relevant issues in addressing sustainable management of terrestrial OC aiming to enhance C sequestration in soil, thus mitigating the impact of increasing CO₂ concentration in the atmosphere and related effects on global climate change. Nowadays, dry combustion by an elemental analyzer or wet combustion by dichromate oxidation of the soil sample are the most recommended and commonly used methods for quantitative soil OC determination. However, the unanimously recognized uncertainties and limitations of these classical laboursome methods have prompted research efforts focusing on the development and application of more advanced and appealing techniques and methods for the measurement of soil OC in the laboratory and possibly in situ in the field. Among these laser-induced breakdown spectroscopy (LIBS) has raised the highest interest for its unique advantages. After an introduction and a highlight of the LIBS basic principles, instrumentation, methodologies and supporting chemometric methods, the main body of this review provides an historical and critical overview of the developments and results obtained up-to-now by the application of LIBS to the quantitative measurement of soil C and especially OC content. A brief critical summary of LIBS advantages and limitations/drawbacks including some final remarks and future perspectives concludes this review.     

Certified reference materials to support a European thematic strategy for soil protection: the EUROSOILS (IRMM-443) experience

The recent proposal of thematic strategy for soil protection by the European Commission outlines that knowledge of problems associated with soil has increased considerably based on surveys, monitoring systems and data networks. Although this information is very useful, its value for the policy-making process is limited due to a lack of comparability. From this unsatisfying situation the need arises to develop an EU-wide monitoring system accompanied by suitable matrix reference materials. Experiences gained from the development and certification of IRMM-443 (The EUROSOILS) show how to approach the complex problem of providing suitable (i.e. representative) soil CRMs for the arising analytical needs to support existing and upcoming EU legislation.This paper presents briefly the quantitative findings of a certification exercise (adsorption coefficients for atrazine, lindane and 2,4-D, as well as pH in suspension). A comparison of these results with those of an intercomparison exercise organised in 1989 by the German UBA on very similar soils shows the significant improvement in the determination of soil adsorption coefficients that was induced by the EUROSOIL project. Indicative values of total and organic carbon content and nitrogen according to ISO Standards are also presented.Furthermore, the idea of reference soils and derived reference materials (for analytical purposes) as well as reference matrices (substrates for ecotoxicological testing) is highlighted and set into the context of horizontal standardisation of methods.     

A simple route to interpenetrating network hydrogel with high mechanical strength

A simple two-step method was introduced to improve the hydrogel mechanical strength by forming an interpenetrating network (IPN). For this purpose, we synthesized polyacrylate/polyacrylate (PAC/PAC), polyacrylate/polyacrylamide (PAC/PAM), polyacrylamide/polyacrylamide (PAM/PAM) and polyacrylamide/poly(vinyl alcohol) (PAM/PVA) IPN hydrogels. The PAC/PAC IPN and PAC/PAM IPN hydrogels showed compressive strength of 70 and 160 kPa, respectively. For the PAM/PAM IPN and PAM/PVA IPN hydrogels, they exhibited excellent tensile strength of 1.2 and 2.8 MPa, and elongations at break of 1750% and 3300%, respectively. A strain relaxation was also observed in the case of PAM series IPN hydrogels. From FTIR, TGA and SEM measurements, we confirmed that physical entanglement, hydrogen bonds and chemical crosslinking played major roles in improving hydrogel strength and toughening. The two-step technique contributes to the understanding of ideal networks, provides a universal strategy for designing high mechanical strength hydrogels, and opening up the biomedical application of hydrogels.     

Application of solid phase microextraction for the determination of soil fumigants in water and soil samples

The potential of solid phase microextraction (SPME) for the determination of the soil fumigants 1,3-dichloropropene (1,3-DCP) and methyl isothiocyanate (MITC) in environmental samples such as soil and water samples has been investigated. Direct immersion SPME followed by GC/ECD/NPD analysis allowed the rapid determination of the two fumigants in water samples, with very little sample manipulation, giving an LOD of 0.5 microg L(-1). Precision, calculated as relative standard deviation (RSD) for six replicates at three concentration levels, was found to be lower than 20% at the concentration levels tested. For the analysis of soil samples, headspace (HS)-SPME combined with GC/ECD/NPD analysis has been applied. Quantification using matrix-matched calibration curves allowed determination of both analytes (MITC and 1-3-DCP) with a LOD of 0.1 microg kg(-1) (RSD < 10%) for the two concentration levels assayed (0.02 and 0.2 mg kg(-1)). The HS-SPME procedure developed in this paper was applied to soil samples from experimental green house plots treated with metham-Na, a soil disinfestation agent that decomposes in soil to MITC. The absence of sample manipulation as well as the low solvent consumption in SPME methodology are among the main advantages of this analytical approach.