两性聚电解质在黄河高浊度水中的应用

本文合成了一系列不同阴、阳离子度的强碱弱酸型的两性聚电解质[丙烯酰胺(AM)-二甲基二烯丙基氯化铵(DMDAAC)-丙烯酸(AA)共聚物]。研究了阴、阳离子单体的配比对两性聚电解质分子量的影响;以及两性聚电解质阴、阳离子度对絮凝效果的影响。并将所合成的两性聚电解质作为絮凝剂,首次应用到黄河高浊度水的处理中。填补了国内两性聚电解质高分子絮凝剂应用于上水的空白。研究结果表明:在等电点范围内的两性聚电解质对黄河高浊度水的絮凝效果明显优于传统的非离子型、阳离子型及阴离子型絮凝剂。     

Influence of flocculant molecular weight and anionic charge on flocculation behaviour and on the manufacture of fibre cement composites by the Hatschek process

Although in the industrial Hatschek process it is necessary to use flocculants to improve retention, dewatering and formation, the use of flocculants may also decrease the strength of the final product. This paper studies the influence of the molecular weight and the anionic charge of anionic polyacrylamides on the flocculation behaviour of fibre cement suspensions and on the bending strength of the final product. Flocculants influence the density of the final product and in-turn the lowering of the density results in strength reduction. Results showed that an increase in the flocculant molecular weight reduces the bending strength of the composites significantly due to its density reduction. However, an increase in flocculant anionic charge increases the bending strength of composites. Therefore, in order to optimise the fibre cement process, it is necessary to use flocculants with high anionic charge and medium molecular weight.     

The shear degradation of high-molecular-weight flocculant solutions

Solutions of polyacrylamide and poly(acrylamide-co-sodium acrylate) flocculants with varying molecular weights were shear degraded under a range of mixing conditions. The viscosity and flocculant activity of the solutions generally decreased with time to limiting values dependent on the mixing intensity. The activity of 10 and 20% anionic flocculants displayed quite different trends from those for nonionic flocculants of equivalent molecular weight, with less apparent degradation due to mixing, particularly at low dosages. However, viscosity measurements on sheared solutions diluted with a salt buffer suggest that nonionic and anionic flocculants with similar initial molecular weights were degraded to the same degree. Multiangle laser light-scattering measurements were used to confirm that the shearing process resulted in a reduction in molecular weight which was independent of anionic character. The apparent shear resistance of anionic flocculation mechanisms for the nonionic and anionic flocculants. © 1996 John Wiley & Sons, Inc.     

Study on chain deformation of polyacrylamides in solutions and its flocculation performance during the flocculation process

Effects of external conditions, solution concentration, solvent quality, added salt, and pH on the chain conformation dimension of two kinds of polyacrylamide (PAAm) flocculants, neutral‐PAAm, and cationic‐P(AAm‐DMC) (DMC, 2‐[(methacryloyloxy)ethyl] trimethylammonium chloride), in parent solutions and their flocculation performance for Kaolin suspensions have been investigated by Ubbelohde viscometer and spectrophotometer, respectively. It was found that a negative correlation existed between the flocculation performance of PAAm flocculants and their chain sizes in parent solutions. This was attributed to the expanded chain deformation of PAAm flocculants during the flocculation process from the flocculant parent solution to the Kaolin suspension and was interpreted in term of the competitive interaction among the polymeric flocculant, solvent, and Kaolin particle in the chain deformation process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

不同絮凝剂对高泥氧化铜浸出液沉降的影响

为解决云南某氧化铜现场生产中酸浸矿浆含泥量高、沉降速度慢、固液分离困难的问题,对其浸出矿浆进行絮凝沉降实验研究. 实验用浸出矿浆浓度为28.73%,考察了絮凝剂种类、用量、浓度对矿浆沉降的影响. 结果表明,明矾、十二烷基丙磺酸钠、聚丙烯酰胺、明胶、改性阴离子型聚丙烯酰胺、改性阳离子型聚丙烯酰胺均不能有效改善沉降速度,而改性非离子型聚丙烯酰胺(GH-6C)可使矿浆沉降速度大大加快. 这是由于GH-6C分子链上的官能团与浸出液中的胶体粒子发生吸附架桥作用,使颗粒逐渐变大而絮凝沉降. GH-6C分子量较大,在水相中流体力学尺寸或体积也较大,絮凝网捕能力也大,可有效降低絮凝剂的使用浓度、提高絮凝效率. GH-6C浓度为0.1%、用量为0.067 g/L时,沉降指标较好.     

阳离子型改性淀粉对稠油废水絮凝性能考察

合成了三种具有不同阳离子度的阳离子型改性淀粉接枝共聚物絮凝剂ZHYC-n,考察了这三种絮凝剂与PAC复配对稠油废水的絮凝性能,并与市售阳离子型聚丙烯酰胺絮凝剂CPAM进行了对比.絮凝实验结果表明,ZHYC-n与PAC复配具有优良的絮凝脱油脱硫效果,随阳离子度增加絮凝效果显著增加.阳离子型絮凝剂分子链上的阳离子电荷密度不是影响絮凝效果的惟一主要因素,阳离子型改性淀粉接枝共聚物具有的多支链型结构可以明显的提高絮凝剂的絮凝效果.     

Flocculation and sedimentation of cane sugar juice particles with cationic homo‐ and copolymers

Rapid flocculation and sedimentation of suspended particles in primary cane sugar juice is achieved using a high molecular weight anionic polymer flocculant. This work reports on efforts to enhance the performance of an anionic flocculant by the addition of cationic polymers. Homopolymers of poly(trimethylammonium ethyl methacrylate chloride) (TMAEMAC) and cationic copolymers of poly(trimethylammonium ethyl acrylate chloride) (TMAEAC) and acrylamide were synthesized and their performance, to enhance the flocculation and sedimentation of cane sugar juice particles, was evaluated by turbidity and settling rate measurements. The charge–patch mechanism best explains the performance of the homopolymers, whereas the action of the copolymers is attributed to the bridging mechanism. The results of this work indicate that the copolymers are more effective than the homopolymers to aid flocculation and sedimentation of the cane sugar juice particles, and that the best‐performing polymers are those that act by the bridging mechanism. Addition of increased amounts of anionic flocculant did not confer an improvement, suggesting that the cationic bridging flocculant targets a different population of particles that is largely responsible for the residual turbidity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 316–325, 2003     

Pigment removal in anaerobically digested effluent through polyelectrolyte flocculation and liquid–liquid extraction

BACKGROUND: Use of flocculation in wastewater treatment involves interactions of polymer with suspended solids and some dissolved organic compounds that can have a significant impact on aggregation process. RESULTS: It was found that a strong interaction between cationic compounds and dissolved pigments in anaerobically digested (AD) wastewater occurred. The interactions were investigated by light adsorption of the pigments using a commercial flocculant added in the solutions and through a liquid–liquid extraction method using a model cationic surfactant (CTAB) dissolved in organic solvents. The absorbance of pigments decreased significantly with added cationic flocculant as the pigments and flocculants formed insoluble complexes that were removed by centrifugation. CONCLUSION: The absorbance results indicate that the pigments can form complexes even at high concentrations (e.g. 2000 mg L^?1) of the flocculants. In addition, the extraction results demonstrated that pigments in the aqueous phase were transferred into the CTAB organic phase due to a strong interaction between the pigments and CTAB. These results suggest that the pigments present in AD effluent could be a negative factor for the flocculation process, probably resulting in the need for a high dosage of flocculants. Copyright © 2012 Society of Chemical Industry     

Synthesis and application of salt tolerance amphoteric hydrophobic associative flocculants

A series of amphoteric hydrophobic-associative flocculants with outstanding flocculation efficiency and salt tolerance, poly(acrylamide/acrylic acid/dimethyl benzyl aminoethyl acrylate chloride), are successfully prepared (named AAB series) and used to flocculate the montmorillonite suspensions. The solution properties of AAB copolymer are systematically evaluated by viscometer, rheology and steady-state fluorescence analysis. The results suggest that the space network structure forming via hydrophobic-associating interaction can increase solution viscosity and improve the bridging capacity of copolymers. Meanwhile, the apparent viscosity in salt solution increases with increase in the concentration of salt stemming from the anti-polyelectrolyte effect of polyampholyte. Further, the flocculation performances of flocculants in 1 wt% montmorillonite suspensions are evaluated by turbidity, optimal dosage and settlement rate measurement. The results elaborate that the flocculation performances of amphoteric hydrophobic-associating AAB flocculants are better than that of commercial flocculants (cationic and anionic polyacrylamide) and homemade cationic flocculant (AAB-0-5) independent of the type and concentration of salt. The novel ampholyteric hydrophobic-associative flocculants will exhibit intriguing prospective in industry water treatment, in that the anti-polyelectrolyte effect of polyampholyte and hydrophobic-associating interaction can endow excellent flocculation efficiency and salt tolerance.     

Interaction mechanism of flocculants with coal waste slurry

Coal tailings are the inevitable by-product of coal mining and preparation plants, and often are problematic in terms of dewatering and solid-liquid separation. The interaction of multi-component fine coal tailings with various coagulants and flocculants are important in dewatering processes. Tunçbilek coal preparation plant wastes are composed of 81% inorganic solids with negative surface charges dominating at all pHs. The highest settling rate and turbidity values without flocculant are obtained at natural pH of 8.3 due to the presence of inorganic ions in the suspension particularly Mg²⁺and Ca²⁺that act as natural coagulants. Additon of medium and low charge density anionic flocculants with high molecular weight at natural pH produced higher settling rates at lower dosages than nonionic and cationic flocculants. It shown that the charge density of anionic flocculants has a significant effect on both settling rate and supernatant turbidity, also the settling rate increases with increasing the degree of anionicity. Anionic flocculants having high molecular weight and high anione charge density produced flocs at sufficient size necessary for settling conditions, yet anionic flocculants having low charge density were more effective in the clarification of suspensions containing clay minerals of high stability. The multivalent ions act as a bridge between negatively charged coal, quartz and clay minerals with anionic groups (-CH₂-(CH-CO)-COO groups) of the polymer. Non-ionic flocculants required higher dosages than other flocculants to achieve equivalent settling rates; though excellent turbidity values were obtained in most common pH values. Cationic flocculants of higher charge densities (%70) achieved good settling rates and low supernatant turbidities (9.9 NTU) at natural pH for a dosage of 119.7 g/t-solids flocculant. An interaction mechanism of each polymer type with different components of the tailings is proposed.     

无机高分子多阳离子铁系絮凝剂的研究进展

无机高分子多阳离子铁系絮凝剂是铁盐等金属离子在水解过程中的中间产物与溶液中带负电荷的溶胶粒及不同阴离子的结合产物。介绍了无机高分子多阳离子絮凝剂中铁系絮凝剂的制备方法,包括聚磷硫酸铁絮凝剂、聚硅铁絮凝剂、聚硅铝铁絮凝剂、聚氯化铝铁絮凝剂,以及这些絮凝剂在印染废水、造纸废水、油田废水、食品工业废水、医药工业废水处理中的应用现状,并对今后的研究方向提出了建议。     

Characterization of cationic starch: An efficient flocculating agent

Starch is a known carbohydrate in which, regardless of its origin, two polysaccharides are found namely amylose and amylopectin. By insertion of a cationic moiety to the backbone of starch, a modified cationic starch can be developed which can be used as flocculant. Various grades of cationic starches were developed to optimize the best performing flocculant. The base polysaccharide, starch and the best performing cationic starch i.e., Cat St3 (which have been confirmed from flocculation characteristics and intrinsic viscosity measurement) have been characterized by various characterization techniques such as determination of molecular weight, elemental analysis, FTIR spectroscopy, intrinsic viscosity measurement, thermal analysis, etc. From the characterization, it could be concluded that there was a substantial incorporation of cationic moiety onto the backbone of starch. The flocculation efficacy of these cationized starches was compared with each other and with some of the commercial flocculants available in national and international market in manganese ore suspensions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Flocculation properties and adsorption kinetics of cationic starches in kaolin suspensions

The flocculation characteristics of cationic starches with degree of substitution (DS 0.32–0.63) have been evaluated in 1.0 wt % kaolin suspension by spectrophotometry and colloid titration. Cationic starch is found to be an effective flocculant for removal of anionic suspension particles. Changes in the electrokinetics of kaolin as a function of pH were investigated in the absence of flocculant. The results show that kaolin in water exhibits a negative surface charge at pH > 2.5. The negative hydrophilic surface sites of kaolin are responsible for the adsorption of cationic starch molecules. The experimental data of the adsorption of cationic starch (DS 0.51) follow a Langmuir isotherm with maximum adsorption capacities of 16.89 mg/g. For the adsorption of cationic starch, chemical reaction seems significant in the rate‐controlling step and the pseudosecond‐order chemical reaction kinetics provides the best correlation for the experimental data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

辽河油田稀油二元复合驱采出污水絮凝处理研究

对辽河油田稀油二元复合驱采出污水进行絮凝处理。优选了无机、有机絮凝剂,考察了复配絮凝剂效果及其加药方式对絮凝效果的影响,研究了不同絮凝剂产生的絮体形态。结果表明,优选的无机絮凝剂为聚合氯化铝(PAC),有机絮凝剂为阳离子聚丙烯酰胺(CPAM),其絮凝效果随阳离子度的提高而提高。有机絮凝剂投加量对复配絮凝剂的处理效果影响较大。适宜的复配药剂投加量为PAC 300 mg/L、CPAM-1 4 mg/L,处理后污水SS的质量浓度为10.65 mg/L、油的质量浓度为2.43 mg/L、透光率为84.0%,絮体较致密。最好的加药方式为投加完无机絮凝剂后,立即加入有机絮凝剂。不同的絮凝剂形成的絮体形态不同,复配时CPAM-1的投加量越大,絮体越致密。     

水分散型阳离子聚丙烯酰胺的絮凝性能研究

通过高岭土模拟废水实验,考察了水分散型聚（甲基丙烯酰氧乙基三甲基氯化铵／丙烯酰胺）（以下简称CPAM）的投加量、阳离子度、分散剂分子量及其与PAC复配对絮凝性能的影响。结果表明,在絮凝过程CPAM表现出两个聚沉点,其适宜阳离子度和分子量范围分别为10％～15％和500×10^4～700×10^4,与PAC复配可显著增强其絮凝效果。     

复合型微生物絮凝剂与化学絮凝剂的复配及其应用

通过实验考察F2–F6复合型微生物絮凝剂分别与无机絮凝剂氯化铝、无机高分子絮凝剂聚合氯化铝、有机絮凝剂聚丙烯酰胺复配使用处理泥浆废水絮凝条件和絮凝效果,并对水源水和工业废水中的处理效果进行了测定。实验结果表明：F2–F6微生物絮凝剂与化学絮凝剂配合使用不仅获得了更好的净化效果,而且可大大降低絮凝剂的总投加量。     

Flocculation of fine particles in ceramic wastewater using new types of polymeric flocculants

It appears to be quite a few national and international studies were reported regarding flocculation and settling properties of ceramic industry wastewater containing various mineral matters. Cleaning of ceramic industry wastewaters with ever increasing environmental standards needs effective and economical solid–liquid separation processes. In this study, quantity and type of optimum flocculant concentration were investigated for solid–liquid separation of Umpac ceramic plant (located at Usak, Turkey) wastewaters. A new generation of flocculants namely unique molecular architecture (UMA) are used to obtain high settling velocity along with high solid content waste and circulation water with low turbidity values. Zeta potential of the tailings including quartz, feldspar, clorite, and mica was also measured at different pH values. The flocculation tests were performed in the presence of different types of polymers at different polymer dosages. It seems that Magnafloc 5250 shows higher performance than the anionic flocculant SPK 508 and other anionic UMA flocculants Magnafloc 6260 and Magnafloc 3230. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis,characterization, and flocculation properties of poly(acrylamide‐methacryloxyethyltrimethyl ammonium chloride‐methacryloxypropyltrimethoxy silane)

A novel hydrophobically modified and cationic flocculant poly(acrylamide‐methacryloxyethyltrimethyl ammonium chloride‐methacryloxypropyltrimethoxy silane) (P(AM‐DMC‐MAPMS)) was synthesized by inverse emulsion polymerization. The molecular structure of hydrophobically cationic polyacrylamide (HCPAM) was characterized by FTIR and ¹H‐NMR. The effects of DMC and MAPMS feed ratio on intrinsic viscosity and solubility were measured. The effects of hydrophobically cationic flocculants on reactive brilliant red X‐3B solution and kaolin suspension were studied. It was found that the introduction of MAPMS could increase the intrinsic viscosities of P(AM‐DMC‐MAPMS) and enhance the flocculation properties to anionic dye solution and kaolin suspension, but reduced their water‐solubility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

水质变化对煤泥水絮凝沉降的影响

以高浓度难沉降煤泥水为研究对象,进行了水的pH、硬度对不同类型絮凝剂沉降澄清效果的影响研究。结果表明：非离子型聚丙烯酰胺在煤泥水pH为9,阳离子型聚丙烯酰胺和阴离子型聚丙烯酰胺在pH为5左右时絮凝沉降效果较好;非离子型聚丙烯酰胺、阳离子型聚丙烯酰胺、阴离子型聚丙烯酰胺在水质硬度分别为17.8,53.4,71.2 mmol/L时絮凝沉降效果较好。     

Water-soluble polymers as retention aids in a model papermaking system. III. Modified polyacrylamides

The pigment retention efficiency, in a model papermaking system, of anionically and cationically modified polyacrylamides was compared to that of the unmodified homopolymer. The anionic polyacrylamide is a much less efficient retention aid, especially at high pH's; the nonionic and cationic polymers perform similarly and without any marked pH dependence. However, it is the nonionic and anionic polyacrylamides which are similarly poor at fiber flocculation, at pH's between 4.5 and 7.5, whereas the cationic polymer is a good fiber flocculant. All three polymers stabilize pigment suspensions. The anionic polymer is not effective in heteroflocculation of mixed dispersions of fibers and pigment, whereas both the nonionic and cationic are good flocculants, the latter being less susceptible to overdosing. Equilibrium adsorption isotherms were determined; the cationic polymers is, unlike the other modified polyacrylamide, very well adsorbed by cellulose fibers. Onto titanium dioxide, polymers adsorbed in the order anionic < nonionic < cationic. A further differentiation of the cationic polymer is that it gives high pigment retention in sheet formation without markedly increasing the resistance to fluid flow through the forming sheet. Although a process of heteroflocculation is postulated for both nonionic and cationic polymers, in the former case it is thought that the primary adsorption is onto titanium dioxide, whereas with the latter it is onto cellulose.