Effect of the parent solution concentration on the flocculation performance of PAAm flocculants and the relation between the optimal parent solution concentration and critical concentrations

Flocculation performance of three kinds of polyacrylamide (PAAm), linear‐PAAm, Al(OH)₃–PAAm hybrid, and star–PAAm, in kaolin suspensions have been investigated by Spectrophotometer. It was found that the flocculation performance of the polymer flocculant is enhanced at the beginning and then impaired with increasing parent solution concentration (C_p) and an optimal parent solution concentration (C_op) exists, which is directly proportional to both critical concentrations of C* and C_s of the polymer in the dilute aqueous solution, and can be roughly expressed by an empirical formula, C_op = 3.1 × 10^?3 + 643.1C_s. The findings suggests that flocculation performance of a given polymer is dependent on both of the interchain association and the chain contact of the polymer chains in the parent solution and in the kaolin suspension, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1585–1592, 2007     

Synthesis of lignosulfonate-acrylamide-dimethyldiallylammonium chloride copolymer and its flocculation performance

In this work, lignosulfonate-acrylamide-dimethyldiallylammonium chloride (LAD) terpolymer was designed and synthesized by microwave-assisted graft polymerization. The optimal synthetic process was obtained as follows: the monomer ratio was 1:4:4, the amount of initiator was 0.9% (w/w), the monomer solid content was 21 wt %, and the reaction time was 14 min with the microwave power of 280 W. Furthermore, the flocculation performance of LAD was verified by removing acid black-172 dye wastewater. At the LAD dosage of 350 mg L⁻¹, the maximum color removal ratio reached 99.8% in 100 mg L⁻¹ of dye wastewater. The dynamics of dye removal reached higher than 90% after 20 s. The flocculant can maintain color removal ratio more than 98% in a wide flocculant dosage and environmental pH. The flocculation mechanism was mainly electrical neutralization and bridging effect. In general, it is a promising candidate in wastewater treatment in terms of cost, synthetic method, and effectiveness. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48560.     

疏水缔合型阳离子聚丙烯酰胺的溶液性能与应用研究

以丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)、丙烯酸十八酯(OA)为单体,用氧化-还原引发体系,通过自由基胶束共聚法制得疏水缔合型阳离子共聚物PADO。研究了共聚物组成对PADO溶液性能的影响,以及PADO对造纸中段废水的絮凝效果。结果表明,PADO水溶液中存在强烈的分子间缔合作用,在处理造纸中段废水时,其应用效果优于聚合硫酸铁、聚合氯化铝和非离子PAM。     

Affine deformation of single polymer chain in poly(methyl methacrylate) films under uniaxial extension observed by scanning near-field optical microscopy

The conformation of single poly(methyl methacrylate) chain in the uniaxially stretched film was observed by the combination of the fluorescence labeling technique and scanning near-field optical microscopy (SNOM). The dimension of the individual probe chain (M_w = 1.99 × 10⁶) along the extension axis was evaluated from SNOM image. In the high molecular weight matrix (M_w = 1.89 × 10⁶) the average extension ratio at the single chain level coincided with the macroscopic extension ratio. The distribution of the chain conformation was in good agreement with that of the freely jointed chain followed by affine deformation. On the other hand, the probe chain embedded in the low molecular weight matrix (M_w = 1.76 × 10⁵) showed the smaller extension than that expected from the affine deformation. This suggests that the conformation of the probe chain is affected by the relaxation of the short surrounding chains through disentanglement.     

The flocculation of kaolin by cationic polyacrylamides and the effect of cationic surfactant on this process

The flocculation of kaolin suspended in a dilute salt solution was studied as a function of the addition of cationic surfactant and cationic polyacrylamide (CPAM) added separately, consecutively, or simultaneously. Cationic polyacrylamide caused flocculation by bridging when added in low concentrations, but at higher concentrations, charge neutralization became the dominant mechanism and the flocculation rate was highly dependent on the charge density of the polymer. Adsorption of sufficient polymer or surfactant (cetyl pyridinium chloride) prevented immediate adsorption of the other, although surfactant could replace polymer after extended agitation. The adsorption of polymer was greatest when small flocs were formed by charge neutralization or by prolonged shaking. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2382–2389, 2002     

天然高分子絮凝剂仙人掌絮凝性能的初步研究

研究了天然高分子絮凝剂仙人掌的絮凝性能,标准水样用高岭土配制。分别处理较高浊度(100~200NTU)和低浊度(20~50NTU)的标准水样,结果表明,仙人掌絮凝剂对浊度的去除率比较高,最终的出水浊度可以达到5NTU。仙人掌絮凝剂的最佳用量与AlCl3·6H2O相比仅仅高一点。可以推测,仙人掌组分中的非极性成分在絮凝过程中起了重要的作用。     

煤泥水处理药剂的探索与实践

介绍了金鸡岩洗选厂工艺流程。通过对原煤性质的分析,说明入洗煤质极度恶化,为煤泥水处理带来困难。通过对煤泥水处理药剂的实验室及工业试验研究,确定了适合煤质现状的药剂组合,使高灰细粒煤泥得到快速有效沉降,达到了降低药剂用量和提高煤泥回收率的目的。     

Energy storage during inelastic deformation of glassy polymers

In this paper, aspects of the microstructural state of glassy polymers that evolve during physical ageing and inelastic deformation were studied. Differential scanning calorimetric (d.s.c.) measurements were performed on specimens of three glassy polymers: polystyrene (PS), polycarbonate (PC) and poly(methyl methacrylate) (PMMA). Materials were subjected to both a quenched and a well annealed heat treatment and subsequently deformed in compression to various levels of strain. Stress-strain curves and companion d.s.c. scans were compared.

The well known enthalpy overshoot at T_g was observed for the annealed samples, showing that ageing is accompanied by enthalpy relaxation. The annealed material was also found to require a higher stress to yield, and the additional work required to strain-soften the annealed polymer to the flow stress level of its quenched companion was found to correlate well with the area of the enthalpy overshoot of the annealed specimen.

Inelastic deformation was found to increase the specific enthalpy of both annealed and quenched specimens. In the annealed material, the enthalpy overshoot at T_g was found to decrease with inelastic strain and was completely erased by about −20% strain. Simultaneously, a pre-T_g exotherm was observed to develop with inelastic strain over a wide range of temperature. The pre-T_g exotherm was found to evolve until essentially reaching a steady-state profile at approximately −25% strain. This evolution coincided with the strain-softening phenomenon observed in the corresponding stress-strain results. A pre-T_g exotherm was also found to evolve with straining of the quenched material. Furthermore, the steady-state exotherms of the quenched and annealed materials were found to be nearly identical, as were their corresponding flow stress values after strain softening.

Finally, a second, post-T_g exotherm was found to develop with further straining beyond strains of −25%. This exotherm was found to increase with inelastic strain and coincided with the occurrence of strain hardening (due to chain orientation) in the materials.

The presence of two distinct and separately evolving exotherms in the inelastically deformed polymers indicates the existence of two separate deformation resistances in glassy polymers, one related to the initial yield and strain-softening behaviour, and the other to the orientation-induced strain hardening of the material. The observation that the pre-T_g exotherm is spread over a wide temperature range reflects the distributed nature of the structural state and may be quantified using a distribution in activation energy for the local rearrangements. The results therefore provide valuable information about the processes that must be accounted for in the development of accurate constitutive models of mechanical behaviour.     

聚合氯化铝-聚丙烯酰胺复合絮凝剂的特性及絮凝作用

制备了无机和有机高分子复合絮凝剂聚合氯化铝-聚丙烯酰胺(PAC-PAM),在不调节pH值、投加量为8mg.L-1(以Al3+计)的条件下,絮凝剂净化长江水的效果最佳,余浊达到4.0NTU以下。通过测定絮凝剂的Zeta电位、观察絮凝剂形貌和处理长江水所形成絮体的形貌、分析絮体的粒度分布,对聚合氯化铝和聚合氯化铝-聚丙烯酰胺进行了比较研究,探讨了复合絮凝剂的絮凝机理。结果发现:聚合氯化铝与聚丙烯酰胺复合后,水解产物带有更多正电荷并具分枝状长链结构,增强了电中和及吸附架桥的作用。     

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。     

有机絮凝剂的现状和未来

从絮凝剂在水处理的作用入手,简单介绍了有机絮凝剂的三大类别：即合成有机高分子絮凝剂、天然有机高分子改性絮凝剂和微生物絮凝剂,同时指出了有机絮凝剂的发展方向。     

含硼聚硅硫酸铁的制备及絮凝效果研究

以硅酸钠、硫酸铁和四硼酸钠为原料，制备了无机高分子絮凝剂含硼聚硅硫酸铁（PFSSB），研究了PF—SSB的制备工艺条件、PFSSB投加量和废水pH对PFSSB絮凝效果的影响。结果表明，当制备工艺条件为：二氧化硅质量分数为3％，活化时间为30min，活化的pH为3，铁与硅物质的量比为0、50，硼与硅物质的量比为0．40时，得到的PFSSB具有最好的性能，用其处理高COD、高浊度工业废水，絮凝效果明显优于聚合硫酸铁（PFS）。     

对腈纶废丝碱法水解产物接枝后絮凝性能的研究

腈纶废丝在常压碱性条件下水解后,与二甲胺进行接枝制备絮凝剂的适宜条件为:NaOH、水、二甲胺用量分别为14 g、160 mL、36 g,接枝温度为90℃,在此条件下制得的絮凝剂对废水的除浊效果可达到92%以上。     

聚硅酸铝锌絮凝剂的制备及其絮凝性能研究

研究了聚硅酸铝锌絮凝剂适宜制备条件和提高絮凝性能的适宜条件。以硅酸钠、氯化铝、氯化锌为原料,制备聚硅酸铝锌絮凝剂,处理含磷废水。结果表明,硅酸钠浓度0.5mol/L,活化p H为4,活化时间60min,n(Al)/n(Si)为2,n(Zn)/n(Si)为3,水样p H为12,静沉时间10min时,含磷废水处理效果较好,除磷率可达98.6%。     

Multifunctional CO2-switchable polymers for the flocculation of oil sands tailings

A series of multifunctional homopolymer and copolymer of 2-dimethylamino ethyl methacrylate (DMAEMA) and N-isopropyl acrylamide (NIPAM) were designed and used to flocculate oil sands mature fine tailings (MFTs). Carbon dioxide (CO₂) protonated the tertiary amine groups of P(DMAEMA) and P(DMAEMA–NIPAM) making their chains positively charged. The pH sensitivity of these polymers favored the flocculation of the negatively charged clays in MFT due to charge neutralization. Three different polymers, P(DMAEMA), P(NIPAM₃₃–DMAEMA₆₇), and P(NIPAM₆₇–DMAEMA₃₃) were synthesized via aqueous free-radical polymerization and used to flocculate MFT in the presence of CO₂. Experimentally, CO₂ was introduced in the system in three different ways: (1) CO₂ was first bubbled into polymer solution, then the polymer solution was added to MFT, (2) CO₂ was first bubbled into MFT and then the CO₂-free polymer solution was added to MFT, and (3) both polymers and MFT were bubbled with CO₂ separately, then mixed together. We compared the effects of the method of CO₂ addition, copolymer composition, and polymer molecular weight on MFT flocculation performance. Our results indicate that CO₂-switchable polymers can be employed to enhance the dewatering of challenging wastewaters such as oil sands tailings. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47578.     

不同折板絮凝器对薄荷水提液的絮凝效果研究与比较

为了优化折板絮凝器结构及提升折板絮凝器对中药液的絮凝效果,利用FLUENT软件对同波/对波折板絮凝器的内部流场进行了模拟,分析了两种折板絮凝器内的涡旋分布及涡量.以薄荷水提液为研究对象,壳聚糖为絮凝剂,采用不同折板絮凝器对薄荷水提液进行絮凝处理,以薄荷水提液澄清层高度、絮体沉降速度、总黄酮保留率、絮凝率、药液吸光度及絮...     

Rheological behavior of polymer solutions during fabric coating

The overall performance of coated products is determined by the intrinsic material properties in solution and processing conditions. To characterize the behavior of these materials, the viscosity of polymers in solution at various concentrations was measured and the experimental data were fitted with the Carreau model. The results describe the rheological behavior of coating materials, and provide a basis for the modeling of polymer flow during the coating process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

聚硅硫酸铝的制备及其对生活废水的絮凝应用

以硅酸钠、硫酸铝为原料,采用复合共聚法制备聚硅硫酸铝(PASS)。以生活废水为对象,以浊度与COD去除率为指标,在不同的处理条件下,观察废水脱色情况,考察聚硅硫酸铝的絮凝效果。结果表明:加入量为0.4g.L-1的PASS,搅拌转速为250r.min-1,搅拌时间为25min,调节水体处于酸性条件下,静置沉降1h后,浊度和COD去除率分别达到90.9%和82.3%,且废水脱去黑褐色。另外还初步阐述了PASS的絮凝机理。     

聚合硅酸硫酸铝的絮凝性能及改性研究

以硫酸铝、水玻璃和铝酸钠为原料制备了聚合硅酸硫酸铝(PASS),研究了PASS絮凝性能,并利用聚二甲基二烯丙基氯化铵(PDMDAAC)和聚丙烯酰胺(PAM)对PASS进行复合改性。结果表明,PASS絮凝条件选择为加药量40 mg/L,A l/S i为10-20,原水在pH值6.0-8.0有较好的絮凝效果。在最佳絮凝条件下处理低浊水时,其除浊率达到97%,通过加入少量PDMDAAC对PASS改性后能显著减少PASS用量。     

天然高分子改性制两性絮凝剂及其性能研究

以天然植物胶粉F691为原料,通过羧甲基化、接枝共聚和曼尼奇(Mannich)三步反应合成出改性两性型絮凝剂(CG-AC),确定了其较佳的制备条件.试验表明:20 mg/L CG-AC与100 mg/L PAC配合使用处理活性红模拟染料废水,脱色率可达68%,效果明显优于对比样PAM-C;CG-AC对造纸混合污泥的絮凝脱水性能优于对比样PHP和PAM-C.