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。     

阳离子聚丙烯酰胺对克雷伯杆菌絮凝效果的研究

采用有机絮凝剂阳离子型聚丙烯酰胺对克雷伯菌菌悬液进行絮凝处理。探讨了浓度、pH值、温度、助滤剂对絮凝剂絮凝及过滤性能的影响,并采用光学显微镜和扫描电子显微镜对菌悬液、絮凝剂和絮体3个方面进行了絮凝形态观察。结果表明,絮凝剂浓度为0.08 g/L,pH=7,温度为37℃时絮凝效果最佳。添加助滤剂Al2(SO4)3.18H2O、CaCl2.2H2O后过滤效果有明显的提高,且絮凝颗粒增大,沉降速度加快。     

温敏型聚合物在稠油污水中的絮凝作用探讨

稠油污水絮凝剂大都是阳离子聚丙烯酰胺(CPAM),但该絮凝剂在稠油污水中高分子长链的伸展受到高温和高矿化度的影响,絮凝效果大大降低。探讨了一种温敏型絮凝剂PA在不同浓度、温度、及不同浓度无机盐(NaCl和CaCl_2)条件下的絮凝作用并与CPAM进行对比。实验结果表明:温敏絮凝剂PA对稠油污水的乳化油和固相悬浮物的去除率较CPAM高,其主要原因是PA在较高温度下发生相分离使溶液亲水性降低、吸附能力增强;温度和无机盐(NaCl、CaCl_2)能促进温敏絮凝剂PA对稠油污水中乳化油和固相悬浮物的去除效果。     

天然改性植物阳离子絮凝剂对洗煤废水的处理研究

基于洗煤废水对环境所造成的危害,研究了一种以植物木粉为原料,通过与醚化剂接枝共聚制得的易降解、且不产生二次污染的天然改性植物阳离子絮凝剂。其对洗煤废水的处理,研究表明,常温下,当pH=6～8,该絮凝剂和聚铝的投入量分别为10 mg/L和5 mg/L时,洗煤废水的浊度、CODCr、固体悬浮物的去除率分别可达到96.8%6,9.3%9,7.9%。     

高浑浊度水混凝及混凝控制指标的研究

高浑浊度水是指浊度较高、有清晰的界面分选沉降的含沙水体。作者在分析高浑浊度水快速混凝特性的基础上,提出了高浊度水的混凝动力学机理及其综合控制指标,并通过试验进行了验证。     

煤泥水pH值对絮凝沉降效果的影响

针对选煤厂循环水浓度高,煤泥水难沉降的特点,研究了煤泥水pH值对絮凝沉降效果的影响。结果表明,煤泥水絮凝沉降应选择中性或偏酸性的环境;非离子型PAM、阳离子型PAM和阴离子型PAM在不同pH值的煤泥水中絮凝沉降效果不同。非离子型PAM在pH值为9,阳离子型PAM和阴离子型PAM在pH值为5时絮凝沉降效果较好。     

阳离子聚丙烯酰胺对甜高梁混合汁中泥沙的絮凝效果研究

以阳离子型聚丙烯酰胺（CPAM）为澄清剂,对甜高粱混合汁中的泥沙进行絮凝处理。实验结果表明,CPAM对水样的絮凝效果良好,糖分损失很小,且在投加量为1．5mg／L时,絮凝效果达到最佳,絮凝率达到78．54％;CPAM最佳投药量处水样的吸光度值随着泥沙含量的升高而变大;甜高粱混合汁中含糖量越低,CPAM的除泥沙效果越好;沉降时间对CPAM的絮凝效果无明显影响;pH对CPAM除泥沙效果有较大的影响,且在pH为5时絮凝效果达到最佳,絮凝率达到85．86％。     

聚丙烯酰胺对氨水中有机悬浮物絮凝作用的研究

对氨水中的有机悬浮物采用聚丙烯酰胺(PAM)进行絮凝。通过絮团特征、清液特征、絮团聚集程度以及氨水中絮团体积的变化率同絮凝时间的关系,比较了不同添加量、不同种类的PAM絮凝效果。结果表明,采用阴离子型聚丙烯酰胺和阳离子型聚丙烯酰胺相结合的絮凝方式,能较好地絮凝氨水中的有机悬浮物。较好的絮凝方式是:在140 r/m in搅拌中,往氨水中加入分子量为1100万、浓度为1‰的阴离子型聚丙烯酰胺15 mL/L,搅拌1 m in;调转速为60 r/m in,加入离子度为20%~25%、浓度为1‰的阳离子型聚丙烯酰胺5 mL/L,搅拌5 m in,静止1 h。     

阳离子聚丙烯酰胺对甜高粱混合汁中泥沙的絮凝效果研究

以阳离子型聚丙烯酰胺(CPAM)为澄清剂,对甜高粱混合汁中的泥沙进行絮凝处理。实验结果表明,CPAM对水样的絮凝效果良好,糖分损失很小,且在投加量为1.5 mg/L时,絮凝效果达到最佳,絮凝率达到78.54%;CPAM最佳投药量处水样的吸光度值随着泥沙含量的升高而变大;甜高粱混合汁中含糖量越低,CPAM的除泥沙效果越好;沉降时间对CPAM的絮凝效果无明显影响;pH对CPAM除泥沙效果有较大的影响,且在pH为5时絮凝效果达到最佳,絮凝率达到85.86%。     

Comparison of the performance of chitosan and a cationic polyacrylamide as flocculants of emulsion systems

Food industries contribute significantly to the pollution of water streams. Oil in wasterwaters must be removed to prevent fouling of process equipment, to reduce interference with subsequent water-treatment units, and to comply with water-discharge requirements. Polyelectrolytes are frequently used to coagulate and flocculate colloidal systems. A model system of a sunflower oil/water emulsion was used to analyze the effect of:(i) emulsion droplet sizes, (ii) surfactant chain length (sodium dodecyl sulfate and sodium tetradecyl sulfate), (iii) ionic strength, and (iv) pH, on the doses of chitosan (natural cationic polyelectrolyte) and a cationic polyacrylamide, necessary to neutralize electrical charge and to get flocculation. Methods used were: turbidimetry, jar test, colloidal titration, and light microscopy observation. Results showed that the increase of NaCl concentration reduces the doses of chitosan and polyacrylamide to reach zero colloidal charge; these doses increase with the surfactant chain length. pH variation did not show any influence on the chitosan dose necessary to flocculate the system. Redispersion of the emulsion was observed in chitosan and polyacrylamide treatments.     

Investigation on flocculation characteristics of polysaccharide-based graft copolymers in coal fines suspension

The article deals with the synthesis of two polysaccharide-based graft copolymers of acrylamide, namely, starch-g-polyacrylamide (St-g-PAM) and amylopectin-g-polyacrylamide (Ap-g-PAM). Intrinsic viscosity of the graft copolymers was determined. A flocculation jar test was carried out with −200# ASTM particles for two coking and two noncoking coal samples from Indian coalfields. It is observed that both the grafted products are very effective flocculants in bringing down the turbidity of supernatant liquid of coking coal fines suspension. Though they are effective flocculants in the case of noncoking coal suspension as well, the supernatant turbidity remains somewhat high. Ap-g-PAM performed better than St-g-PAM, which is distinctly apparent in the case of noncoking coal suspension. This may be ascribed to the presence of longer grafted polyacrylamide chains in case of Ap-g-PAM. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2619–2625, 1998     

阳离子表面活性剂在活性炭上的吸附研究

利用表面张力法测定了活性炭自水溶液中吸附阳离子表面活性剂3－烷氧基－2－羟丙基三甲基氯化铵（CnNCl)的吸附等温线,应用热力学公式计算出了吸附过程的ΔG^0、ΔH^0和ΔS^0,实验结果表明,CnNCl同系物的吸附量随温度的升高而降低,随表面活性剂中疏水基碳链的增长而升高。吸附过程为一熵增加过程。     

用弗雷德盐沉降去除水体中镉的絮凝形态

用微/纳结构的弗雷德盐乳液作吸附-絮凝剂以絮凝法去除水体中重金属镉。结果表明,弗雷德盐絮凝沉降镉的去除率达97.8%。背散射与点能谱的研究表明,弗雷德盐在水处理过程中经历了溶解-再结晶,形成稳定性更高的六方柱形方解石和无定型氢氧化铝。水体中部分镉离子吸附或共沉淀在六方柱形方解石表面;另有部分镉离子吸附或共沉淀在水解生成的无定形氢氧化铝胶体中。XRD谱图比较证实,还有部分镉以类质同象取代方解石中的钙进入晶格。     

Mass transport process for the adsorption of Cr(VI) onto water‐insoluble cationic starch synthetic polymers in aqueous systems

Dynamic adsorption behaviors between Cr(VI) ion and water‐insoluble amphoteric starches was investigated. It was found that the HCrO ion predominates over the initial pH ∼ 2–4, the CrO ion predominates over the initial pH ∼ 10–12, and both ions coexist over the initial pH ∼ 6–8. The sorption process occurs in two stages: the external mass transport process occurs in the early stage and the intraparticle diffusion process occurs in the long‐term stage. The diffusion coefficient of the early stage (D₁) is larger than that of the long‐term stage (D₂) for the initial pH 4 and pH 10. The diffusion rate of HCrO ion is faster than that of CrO ion for both processes. The D₁ and D₂ values are ∼ 1.38 × 10⁻⁷–10.1 × 10⁻⁷ and ∼ 0.41 × 10⁻⁷–1.60 × 10⁻⁷ cm² s⁻¹, respectively. The ion diffusion rate in both processes is concentration dependent and decreases with increasing initial concentration. The diffusion rate of HCrO ion is more concentration dependent than that of CrO ion for the external mass transport process. In the intraparticle diffusion process, the concentration dependence of the diffusion rate of HCrO and CrO ions is about the same. The external mass transport and intraparticle diffusion processes are endothermic and exothermic, respectively, for the initial pH 4 and pH 10. The k_d values of the external mass transport and intraparticle diffusion processes are ∼ 15.20–30.45 and ∼ −3.53 to −12.67 kJ mol⁻¹, respectively. The diffusion rate of HCrO ion is more temperature dependent than that of CrO ion for both processes. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2409–2418, 1999     

Trace-element distribution in various solvent refined-coal fractions as a function of the feed coal

Solvent-refined coal (SRC), a tetrahydrofuran soluble and insoluble SRC derived from five different feed coals have been analysed for twelve metallic elements via flameless atomic absorption spectroscopy. Correlations of metal content in the SRC and pilot-plant processing conditions are discussed. A comparison of these data with previously reported metal analyses via energy-dispersive X-ray fluorescence analysis of similar SRC solid products is discussed. Three of the coals have been separated according to effective molecular size by gel-permeation chromatography and metal analyses have been performed on selected fractions. The possibility that some of the metals may be organically bonded is discussed.     

高分子质量聚氧化乙烯(PEO)和阳离子纤维素聚合物对于护发产品调理性能的协同效应

洗发体系中，同时使用高分子量聚氧化乙烯(PEO)和阳离子羟乙基纤维素(HEC)可以提供卓越的调理性能。用含有阳离子HEC和高分子量PEO的配方清洁头发，湿梳理性比仅含阳离子HEC的配方改善30％。与PEO结合使用，阳离子HEC控制的硅油和甲氧基肉桂酸辛酯(OMC)的吸附量分别有27％和25％的提高。极化显微镜观察发现，已稀释配方中聚合物一表面活性剂络合物(凝聚物的外观)在PEO存在时发生变化。含有PEO和阳离子HEC的配方，凝聚物的粒径更细小。这些结果表明：PEO阻止凝聚物聚集，以减小吸附颗粒大小。表面分析也显示：含有阳离子HEC的配方中存在PEO时，不溶性活性物在头发表面的吸附更加均匀。     

改性木素与聚铁复配体系对水中Cu2+的絮凝性能研究

木素磺酸钙和丙烯酰胺通过自由基聚合,合成了木素基重金属絮凝剂(LSAM).研究了LSAM与聚合硫酸铁(PFS)复配去除铜离子的效果.考察了絮凝剂投加量、pH、沉降时间等因素对铜离子去除率的影响.在最佳投加量(LSAM 140 mg/L+PFS 150 mg/L)下,pH在6.0左右,沉降时间30 min,Cu2+的去除率可达到98％.     

A study of acetoacetoxyethyl methacrylate hydrolysis in acrylic latex polymers as a function of pH

Acetoacetoxyethyl methacrylate (AAEM) is an ambient crosslinking monomer that, when incorporated into architectural coatings binders, provides coatings with improved hardness, scrub, stain, and dirt pick-up resistance. This study details the use of NMR spectroscopy to explore the hydrolysis profile of AAEM as a function of pH, type of neutralizer, and glass transition temperature of the binder. We have determined that AAEM has a hydrolysis profile that is independent of latex polymer pH relevant to coatings (pH 7–10). Lower T _g latex polymers enable the diffusion of ammonia into the binder nanoparticles converting a larger amount of the acetoacetoxy moiety to the enamine form; this approach also allows for measuring the distribution of enamine and AAEM form in the latex polymer particle. The consequence of these findings is that AAEM may be utilized at a lower pH than previously envisioned without consequence to the hydrolysis profile of the acetoacetoxy functionality.     

Generation of orthorhombic polyoxymethylene in a cationic polymerization system of trioxane

Orthorhombic polyoxymethylene, which was originally found two decades ago in Italy in a polymerization system of aqueous formaldehyde, has been rediscovered in a cationic polymerization system of trioxane designed to grow needle-like polyoxymethylene single crystals. Besides the single crystals obtained in the liquid phase, it has been known that a thin film bearing a number of particles, up to ～ 1 mm diameter, is formed as a by-product on the inner wall in contact with the gaseous phase. X-ray analysis has now revealed that the particles consist essentially of the orthorhombic crystalline form. The morphology has been investigated and the growth mechanism briefly discussed.