Characterization of Glass Beads Surface Modified with Ionic Surfactants

Knowledge of the wetting characteristic of mineral surfaces is very important in enhancing the efficiency of separation of valuable minerals from gangue using froth flotation or oil agglomeration. In this paper a capillary rise technique was used to characterize the glass beads surface modified with cationic surfactant. The glass microspheres were used as model particles with a spherical shape and smooth surface to eliminate the roughness effect. The value of the contact angle for water was found to be 21.5 for unmodified beads, and 61.8, 89.7, 68.4 for 0.1, 1.0, 10 mg/g_solid of CTAB, and 39.8, 68.6, 87.9 for 0.1, 1.0, 10 mg/g_solid of DDAHCl, respectively. Data revealed that the adsorption of surfactant onto glass beads decreased the value of the electron donor component, γ-, which defines the hydrophobicity of the surface. Also, the property of the surface was investigated by flotation and oil agglomeration experiments. It was observed that particles with low value of contact angle for water and high for 1-bromonaphthalene and low value of γ- were floated with a recovery equal to 91.1 and 83.1% for CTAB and DDAHCl, respectively, and effectively agglomerated. This indicates that the capillary rise method can be successfully used to predict the wetting properties of solid particles in mineral processing.     

阳离子型聚丙烯酰胺技术条件及絮凝性能评价研究

国家《节能减排"十二五"规划》中,在加强城镇生活污水处理设施建设方面,要求到2015年我国城市污水处理率和污泥无害化处置率分别达到85%和70%。阳离子型聚丙烯酰胺作为一种性能良好的污水处理与污泥脱水剂,被广泛应用于污水处理、污泥脱水处理中。阳离子型聚丙烯酰胺具有优良的选择性和适应性,目前世界有五大系列2 000多个品种,世界年总需求量为65万t,年需求增长率为10%。今后我国污泥脱水处理、污水处理、石油开采、造纸等领域对阳离子聚丙烯酰胺的需求量将不断增长。针对阳离子型聚丙烯酰胺制定了系列质量评价方法并对其在水处理应用方面进行了研究。     

Fe2＋/ATP复合催化剂处理阳离子红X-GRL的研究

以凹凸棒分散液为吸附剂, Fe2＋/ATP为复合催化剂对印染废水中的阳离子红X-GRL进行处理实验。主要分析了Fe2＋负载时间、反应温度和Fe2＋溶液浓度对吸附性能的影响以及影响凹凸棒土联用Feton法与阳离子红反应的因数。实验结果显示,制备ATP/Fe2＋的合适的条件为：凹凸棒土煅烧温度为400℃;负载铁时间为5 h;负载铁浓度为1500 mg/L;负载温度为80℃。     

阴阳离子表面活性剂自发形成囊泡的影响因素

在阴阳离子表面活性剂(SDS/CTAB)复配体系中自发形成囊泡。通过TEM、Zeta粒径分析和表面张力测定等手段进行表征,结果表明浓度、温度、溶剂、pH值等因素对囊泡稳定性有影响,在T=40℃,40%的乙醇为溶剂,调控pH=5,复配浓度在2×10-3mol/L条件下形成的囊泡稳定性最佳。     

^60Coγ辐照水稻秸秆制备阳离子吸附剂的研究

采用辐照法将二甲基二烯丙基氯化铵接枝共聚于预处理的水稻秸秆,考察了产物对于阴离子染料和COD的吸附性能,结果表明接枝后秸秆有吸附阴离子的效果.研究了溶液pH值、吸附时间和温度对吸附过程的影响,吸附剂对于阴离子染料与COD的最大吸附量分别为335 mg/g和73 mg/g.     

阳离子聚丙烯酰胺溶液黏度降低的研究

降低聚丙烯酰胺的黏度对于研究聚合物驱采油及其采出水的处理、煤气化灰渣的循环利用等有重大意义。本文考察了pH值、氧化物及矿化度对阳离子聚丙烯酰胺溶液黏度的影响,实验结果表明当pH值达到8.5时,阳离子聚丙烯酰胺溶液黏度急剧下降;当NaClO加入浓度达到60 mg/L时就能有效的分解聚丙烯酰胺;当NaCl加入量在250 mg/L时就能使聚丙烯酰胺溶液的黏度降低一半。     

Colonization and Infection of the Skin by S. aureus: Immune System Evasion and the Response to Cationic Antimicrobial Peptides

Staphylococcus aureus (S. aureus) is a widespread cutaneous pathogen responsible for the great majority of bacterial skin infections in humans. The incidence of skin infections by S. aureus reflects in part the competition between host cutaneous immune defenses and S. aureus virulence factors. As part of the innate immune system in the skin, cationic antimicrobial peptides (CAMPs) such as the β-defensins and cathelicidin contribute to host cutaneous defense, which prevents harmful microorganisms, like S. aureus, from crossing epithelial barriers. Conversely, S. aureus utilizes evasive mechanisms against host defenses to promote its colonization and infection of the skin. In this review, we focus on host-pathogen interactions during colonization and infection of the skin by S. aureus and methicillin-resistant Staphylococcus aureus (MRSA). We will discuss the peptides (defensins, cathelicidins, RNase7, dermcidin) and other mediators (toll-like receptor, IL-1 and IL-17) that comprise the host defense against S. aureus skin infection, as well as the various mechanisms by which S. aureus evades host defenses. It is anticipated that greater understanding of these mechanisms will enable development of more sustainable antimicrobial compounds and new therapeutic approaches to the treatment of S. aureus skin infection and colonization.     

丙烯酰胺-甲基丙烯酰氧乙基三甲基氯化铵共聚物的制备研究

用过硫酸铵(KPS)引发甲基丙烯酰氧乙基三甲基氯化铵(DMC)与丙烯酰胺(AM)单水相共聚,制备了阳离子聚丙烯酰胺类絮凝剂P(DMC-AM),并应用于废水。探讨了单体总量、引发剂用量、pH值、反应时间等因素对聚合物的特性粘数和粘均分子量的影响。结果表明,P(DMC-AM)粘均分子量可达1.72×107g/mol,对废水浊度的去除率达到80%以上,是一种性能优良的絮凝剂。     

微波条件下水分含量对淀粉醚化反应的影响

以木薯淀粉为原料,3-氯-2-羟丙基三甲基氯化铵为阳离子醚化剂,自制碱性复合催化剂为醚化催化剂,采用微波法制备阳离子淀粉。研究探讨不同醚化剂用量、不同微波功率、不同微波时间条件下,反应体系水分含量对阳离子醚化反应效率的影响。结果表明,不同的醚化剂用量、不同的微波功率及不同的微波时间组合,获得最佳醚化反应效率所需的反应体系水分含量各有不同。醚化剂用量较高时,选用较高的体系水分含量以及较高的微波功率和较长的微波时间,可获得较高的醚化反应效率;醚化剂用量较低时,选用中等的体系水分含量以及中等的微波功率和较长的微波时间,可获得较高的醚化反应效率。     

典型南方源水的有机高分子助凝研究

对我国南方某典型源水的有机高分子助凝效果进行了研究,分别进行了烧杯试验和中试验证。结果表明:阳离子型PAM是较适合当地水质情况的助凝剂,其投量应选在0.03～0.10mg/L,助凝效果最显著地体现在聚合氯化铝(PAC)投量≤2.0mg/L阶段;投加时间点应在PAC投加1min后;搅拌强度为100～300r/min;PAM溶液(浓度为0.1%～0.4%)放置二周其助凝效果也不会发生明显变化。在沉速试验中发现,助凝剂在不同投药时间点(如同时投药或1min后投药)的絮体形成和沉速差别明显,但在沉后静置20min后余浊差别甚微,这将导致不同设施在实施助凝处理时的效果不同。