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To avoidcomplexities arising from acid-catalyzed persulfate decom-position for the MAAP aquifer material the degradationkinetics for this system at the high persulfate concentrationwere determined using data collected during the first 80 d.Best-fit reaction rate coefficients (kobs) for the low persulfateconcentration systems varied from 10 3to 10 2d 1for the7 aquifer materials used (Table 1). The kobs for the highconcentration experiments was estimated to be between 6and 39% of the kobs for the low concentration experimentsindicating higher persulfate stability at higher concentrationsgiven the same mass of aquifer solids. This observation isconsistent with other findings (21) which have shown thatat a given temperature kobs increased with a decrease inpersulfate concentration. In general, the estimated kobs showthat persulfate half-life varies from ∼15 to 600 d in thepresence of aquifer materials over a range of persulfateconcentrations and hence appears to be stable at this scaleof investigation.
From the observed persulfate degradationtrends it is clear that the stability of persulfate over a long-term(weeks tomonths) cannot be evaluated based on batchtests conducted over a 10-day period (13).Since kobs for the aquifer materials are up to an order ofmagnitude higher than those which can be estimated fromeq 4 for pH>3at20 °C, the enhanced degradation of persulfatein the presence of aquifer solids is due to reactions withtransition metal catalysts and other reductants (e.g., NOMand reduced inorganics) associatedwith these solids (28, 29).Persulfate reactions with mineral catalysts are not well-characterized (28), but based on homogeneous aqueoussolution studies the persulfate degradation rate law in thepresence of transitionmetal catalysts can be represented asfirst-order with respect to persulfate concentration and 3/2-order with respect to the catalyst concentration (21, 29–31).The reaction between persulfate and NOM is complicated(14, 15, 22, 24), and various reaction orders have beenproposed provided there is no mass transport limitation(22–24, 30).In this investigation we are interested in capturing thebehavior of persulfate decomposition in subsurface systemsso an appropriate rate expression can be given by
丙烯酰胺/4 -苯乙烯磺酸钠共聚物和半互穿聚合物网络由明胶和/或聚乙二醇染料的溶胀和吸附的初步研究
摘要：半聚水凝胶基于凝胶（GEL）和/或聚（乙二醇）（PEG）制备丙烯酰胺（AAm）和4 -苯乙烯磺酸钠，（SSS光谱标准物质）作为一种阳离子染料（甲基紫MV）的加水吸附剂。为此，化学交联的共聚物，丙烯酰胺/ SSS凝胶和/或PEG共聚物的制备通过水溶液聚合的丙烯酰胺和SSS采用过硫酸铵（APS）/N,N,N’,N’-四甲基乙二胺（TEMED）作为氧化还原引发对中存在的聚（乙二醇），二丙烯酸酯（PEGDA）为交联剂。傅里叶红外光谱（FT-IR）分析被用来确定在半互穿网络不同的重复单位的存在。用扫描电镜（SEM）表征了表面形态。有些溶胀和扩散特性适合于不同的半互穿网络和多种的配方下制备的水凝胶。吸水性和交联聚合物体系对染料的吸附性，譬如AAm/GEL/SSS, AAm/PEG/SSS 和 AAm/GEL/PEG/SSS水凝胶体系研究了水凝胶的化学组合物的功能系统。MV已经用在吸附研究。论文网
关键词：丙烯酰胺/ 4 -苯乙烯磺酸钠、聚电解质水凝胶、溶胀、染料的吸附、甲基紫。
简介：吸水性凝胶或“饥饿网络”占了大量的生物医学和技术应用。高度溶胀的聚合物凝胶化与吸收大量水的能力又是在调查研究中，由于其潜在的应用生物工程，生物医学，和其他相关领域。许多合成和天然来源的材料对形成特征的水凝胶进行了研究。研究已报道的水凝胶或亲水性交联聚合物或共聚物用作去除重金属的吸附剂，用于染料的回收，对有毒或放射性元素从各种废水和金属预浓缩从水溶液中除去的环境样品分析。在一些工业印染废水具有高的颜色和有机质含量。有色的河水也影响我们用于饮用和其他城市农业用途的美丽的土地。已经提出了许多方法用于除去染料，重金属和其他有害物质。化学沉淀法、膜萃取法、混凝法、溶剂萃取法、离子交换法和吸附法是一些常用的方法，但每种方法在其应用方面优缺点。使用不同的高分子材料和合成树脂的吸附法或离子交换法是某些发达国家从化学过程工业的的染料去除大部分废水处理工艺方法选择的方法。超级挡水的水凝胶，它是以高度溶胀的聚合物吸附剂的化学催化剂，用于离子交换行业的色谱填料，原材料，水净化，分离过程和农业著称的。用于从废水中去除或水溶液中的染料的聚合物水凝胶的使用已经在最近几年持续吸引大量的关注。