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％。     

Aggregate structures formed via a bridging flocculation mechanism

A high molecular weight cationic polyelectrolyte has been used to flocculate a colloidal dispersion of anionic polystyrene latex particles. The polymer used had a high charge density and the flocculation occurred at a solution pH where both the polymer and the particles were fully charged. Under these conditions, flocculation is expected to occur through a bridging flocculation mechanism. Low angle laser light scattering has been used to follow the flocculation process as a function of time; parameters of interest were the aggregate sizes, size distributions, and aggregate mass fractal dimensions. The light scattering measurements showed that the flocs formed had a mass fractal character. All the systems examined here were overdosed with respect to the optimum flocculation concentration of polymer. Under these conditions, decreasing the polymer concentration was seen to result in an increased flocculation efficiency. A secondary growth process was also observed whereby initially formed fractal aggregates can subsequently aggregate again. These larger aggregates are also expected to be mass fractals although this cannot be determined from the light scattering measurements due to the superposition of Fraunhofer diffraction effects. This type of fractal-in-fractal character is unusual.     

Parameters affecting the performance of polyelectrolytes as aids to water clarification

An investigation of the flocculation of silica and alumina suspensions by a series of synthetic flocculants of a wide range of charge density both anionic and cationic in nature has been carried out. The extent of flocculation was determined by measurements of settling rate, sediment volume and supernatant clarity. The effect of the pH of the suspension on the performance of a number of selected polymers has been investigated. In the systems examined, flocculation was largely controlled by the charge carried by the suspended particles and polymer molecules. The dosage/settling rate characteristics of kaolin suspensions flocculated with non-ionic polymers of varying molecular weight are reported. The dosages of non-ionic polymers required for optimum flocculation of kaolin suspensions of varying solids content have been measured. At low particle concentrations bridging is less effective, and is probably reduced due to the adsorption of polymer molecules on to single particles.     

磁加载絮凝处理含铜废水

目前磁加载絮凝技术已被研究用于处理多种类型的废水,然而关于此技术中磁粉作用机理方向少有报道。为了解决这一问题,本文采用磁加载絮凝法处理模拟微蚀铜废水,研究了磁粉的加入对Cu²⁺和浊度去除率、絮体沉降速率以及絮体粒径的影响,深入分析了磁粉的作用规律和机理,为磁加载絮凝法应用到实际工程中提供了理论依据和技术参数。结果表明,当磁粉投加量和粒径分别取2.0g/L和300～400目时,磁加载絮凝效果最好。此时,Cu²⁺和浊度去除率均达到最高值98.53%和94.72%,比传统絮凝法高出4.11%和0.61%;絮体沉降速率最快,达5cm/min,是传统絮凝沉降速率的3.64倍;絮体粒径D₅₀也达到最大值41.94μm,较传统絮体粒径大20μm。磁粉投加量过多或过少、粒径过大或过小都会相应地减慢磁絮体的生长速率。     

二甲基二烯丙基氯化铵聚合物的除浊性能研究

研究了二甲基二烯丙基氯化铵聚合物（PDMDAAC）系列絮凝剂对高岭土模拟水样的除浊效果及其影响因素；借助于微电泳技术，探讨了该系列絮凝剂的絮凝机理，并考察了其与PAC复配的除浊效果。实验结果表明：PDMDAAC系列絮凝剂具有优良的除浊效果，尤其对于高浊水；絮凝剂的特性粘度越高，阳离子度越高，除浊效果载好；PDMDAAC系列絮凝剂具有电中和和吸附架桥两种功能，与PAC复配，PDMDAAC系列絮凝剂可使除浊效果更佳而且可以降低处理成本。     

A pilot-plant study of the adsorptive micellar flocculation process: Optimum design and operation

A pilot-plant scale study of the adsorptive micellar flocculation (AMF) process is presented for the first time, and builds on the solid foundation provided by previous fundamental laboratory studies. A number of experimental tests were conducted to validate the feasibility of using an AMF pilot rig to remove phenol from aqueous effluent streams. Several key factors, including flocculation time, floc settling time, optimum air flow-rate for agitation, and flocculant dosage, were determined. Residual concentrations in treated water indicated a surfactant removal efficiency of 95–98%, and pollutant removal reached 78% in two stages of process operation. A strategy for the separate recycling of surfactant, flocculant and pollutant has already been developed. The present study has thus made further progress in developing, testing, validating and optimising the operating conditions of a pilot-scale process. As such, it has demonstrated the feasibility of scaling up from the bench-scale to a commercial, continuously operated unit.     

全氟或多氟烷基物质水处理技术研究进展

自然界废水和饮用水中发现了大量的全氟烷基和多氟烷基物质（PFASs）,因此全氟或多氟烷基物质已成为有机污染物类的全球问题。常规的水处理技术包括混凝、絮凝、过滤、沉淀与生物处理过程都不能完全地去除PFASs。而特定的先进处理技术包括吸附、膜处理与光催化可以有效地去除PFASs,故需要了解深度处理过程中各种PFASs的去除机制,各种PFASs的不同物理化学特性使研究化合物在水溶液中迁移较为困难。在现有研究中关于水质条件对去除PFASs的影响的信息很少,本文全面总结了在不同水质条件下（如pH、温度、溶液中离子、天然有机物和溶质浓度）对去除PFASs的影响,以及先进水处理技术如吸附、膜处理和光催化技术的最新知识。     

Flocculation characteristics of kaolin

The effect of metal cations on the flocculation behaviour of kaolin was investigated.The effects of pH, concentration of cations (Mg²⁺ and Al³⁺), and the presence of these cations in causticised cassava starch on the settling rate and percent reduction in sediment density were studied. Results show that the presence of high concentrations of divalent (Mg²⁺) and trivalent (Al³⁺) ions, and the presence of these cations in causticised cassava starch significantly contributed to the existence of low settling rates at high supernatant clarity often observed in some clay slurry treatment systems by flocculation and sedimentation method. It was also established that for efficient flocculation, the systems must be within the alkaline pH range (pH>10). The study further revealed that in some flocculation systems, fast settling corresponds to high sediment volume whereas in others, the opposite applies. It is therefore concluded that this phenomenon should be taken into consideration for proper design and operation of such treatment facilities.     

絮凝强化铁炭微电解预处理酯化废水的研究

研究了单一铁炭微电解预处理酯化废水的效果,通过正交和单因素试验考察了p H、水力停留时间、填料量和曝气时间等因素对处理效果的影响,并确定最佳反应条件,在此基础上进一步考察絮凝对COD去除效果的影响。结果显示:进水p H对处理效果影响最大,加碱絮凝适合处理酯化废水,在p H=2、HRT=2 h、填料量30%、曝气时间5 min、加碱(p H介于8.5~9.5)絮凝沉淀2 h的条件下,处理效果最佳,COD去除率达到30%以上。     

Removal of Dyes by Biodegradable Flocculants: A Lab Scale Investigation

Abstract

In the present communication, experiments were conducted to investigate the efficiency of mucilage isolated from fruits of Coccinia indica for the treatment of simulated textile wastewater samples containing direct dyes, direct fast scarlet (DFS) and direct fast yellow (DFY) and vat dyes, golden yellow (GY) and nyanthrene yellow (NY). This mucilage (Ku) is an ecofriendly and low cost anionic polysaccharide capable of reducing color from textile effluent through flocculation process. The flocculation efficiency of Ku was improved by grafting polyacrylamide onto it. The copolymer thus obtained (Ku‐g‐PAM) showed much better flocculation capacity than that of its precursor by reducing the flocculant dose and treatment time to half. The results showed that the maximum removal was obtained at acidic pH with both the flocculants. Statistical analysis showed that the change in percent removal with pH was highly significant in case of direct dyes while it was significant in case of vat dyes removal. The plausible mucilage‐dye interaction and flocculation mechanism has been discussed.     

Consolidation and aggregate densification during gravity thickening

A continuous laboratory column system has been used to investigate the consolidation behaviour of kaolin slurries flocculated by a nonionic flocculant under different conditions. Measurements of the steady-state bed density profile showed that higher agitation intensities during flocculation resulted in lower bed densities. The relative importance of compression versus shear for kaolin dewatering was determined by operating the steady-state column system at different bed heights above a mechanical rake. It was found that rake action, not compression, was the dominant dewatering mechanism. Samples taken from the consolidating bed before and after the rake were analysed by microscopy to determine the density–size relationship of the individual aggregates. This showed that the dewatering induced by the rake action occurred not only by removal of inter-aggregate liquor but also by densification of the aggregates (i.e. removal of intra-aggregate liquor). Measurements made on full-scale thickeners are also presented which demonstrate similar behaviour.     

壳聚糖絮凝剂处理水源水中有机物的试验研究

研究了壳聚糖絮凝剂的絮凝特性,进行了壳聚糖絮凝剂跟无机絮凝剂复合絮凝对水源水中浊度和有机物去除的试验。实验结果表明,复合絮凝能够相互促进各自的絮凝性能,显著提高有机物的去除效果,并使除浊和去除有机物得到了统一。在壳聚糖絮凝剂分别与三种常用无机絮凝剂(硫酸铝、氯化铁和聚合铝铁)的复合絮凝的效果的实验表明,其中聚合铝铁跟壳聚糖的复合絮凝剂的效果最好,在最佳条件下,其浊度、CODMn和UV254的去除率分别达到了97％、44％和55％。     

Population Balance Model (PBM) for flocculation process: Simulation and experimental studies of palm oil mill effluent (POME) pretreatment

The present study is intended for the first time to completely replace the inorganic coagulants with organic polymers in palm oil mill effluent (POME) pretreatment by using direct flocculation of single and dual polymer systems under applied shear. The efficiency of direct flocculation of POME was investigated by using the Population Balance Model (PBM) which considered the charge neutralization and bridging attraction under applied shear. The collision efficiency was calculated based on the Derjaguin Landau Verwey Overbeek (DLVO) theory which considered the effect of adsorbed polymer layers on van der Waals attraction and bridging attraction. This is the first attempt to correlate the floc size distribution from PBM to the indirect indicators of COD, suspended solids, oil and grease. The model predictions are in close agreement with the experimental results for both single and dual polymer systems. The interaction energy curves based on PBM shows that the flocculation using cationic polymer is by charge neutralization and bridging attraction whereas flocculation using anionic polymer is by only bridging attraction. At the optimum flocculation conditions, 99.66%, 55.79%, 99.74% and 80.78% of suspended solids, COD, oil and grease removal and water recovery are achieved, respectively. The direct flocculation process significantly reduced the treatment cost by a factor of 3.6 compared to the conventional coagulation–flocculation process.     

Microprocesses of liquid extraction

The extraction mechanism has been considered and the crucial role of the dynamic interfacial layer has been noted. The microprocesses that take place in extraction systems and are associated with the Marangoni effect, the loss of hydrodynamic stability, partial dispersion, coalescence, flocculation, the Ostwald ripening of drops, chemical reactions, the emergence of a new phase, adsorption, coagulation, the formation of structures, and polymerization have been described. For LnCl₃–H₂O–diluent systems (heptane, toluene, tetrachloromethane), data on the shift in the boundaries of the observed transition region over time have been presented. The mechanism of the transfer of the substance in the transition region of the extraction system has been formulated.     

甜水混凝除杂的净化效果

甜水是油脂水解制取甘油的粗产物,甜水除杂净化是甘油精制的重要环节。本文提出了混凝净化油脂水解甜水的新工艺,研究了相关因素对除杂净化效果的影响。得出当pH值调节阶段pH值为11.4、搅拌转速大于300r/min、搅拌时间为60min、混凝阶段的混凝剂用量为75mg/L、絮凝剂用量为20mg/L、絮凝转速为100r/min、絮凝时间为30min时,为最适宜的除杂净化操作条件参数,甜水混凝除杂的效果最佳。研究结果表明:采用该方法得到的净化甜水较传统工艺的皂化当量和浊度更小,沉渣易于分离,混凝过程中不破坏脂肪酸结构,可以回收再用。该方法在甜水除杂净化实际生产中具有较大的应用推广价值。     

廉价培养酱油曲霉产生物絮凝剂的研究

考察了味精废水培养生物絮凝剂产生菌--酱油曲霉(Aspergillus sojae)的条件,比较了在三种不同培养基中该菌种发酵产生絮凝剂的情况.实验结果表明:利用不同培养基培养酱油曲霉,产生絮凝剂的最大絮凝活性基本相当,最大絮凝活性出现时间的先后顺序为:查氏培养基、含蔗糖味精废水培养基、不含蔗糖味精废水培养基.实际废水净化实验表明:产生的絮凝剂对多种废水具有良好的净化效果,对染织厂废水处理的效果最好,CODCr、色度、浊度的去除率分别为72%、97.3%、96.2%.     

Separation of Contaminants from Deinking Process Water by Dissolved Air Flotation: Effect of Flocculant Charge Density

Abstract

The effect of charge density of 5 cationic polyacrylamides (C-PAMs) and 3 anionic polyacrylamides (A-PAMs) in single and in dual treatments with a coagulant on the flocculation and removal of dissolved and colloidal material by dissolved air flotation (DAF) in papermaking has been studied. In single systems, good results were achieved both with low and high charge C-PAMs (1.0 and 3.0–3.5 meq/g). In dual systems, high charge C-PAMs (3.0–3.5 meq/g) and A-PAMs (1.5 meq/g), were the most efficient. Results show that monitoring flocculation by a focused beam reflectance measurement (FBRM) allows papermakers to optimize the chemical dosages to maximize the separation efficiency of DAF units either with single or dual systems, which is not always possible with traditional methods as charge titration.     

Removal of Cadmium from Dilute Solutions by Hydroxyapatite. III. Flocculation Studies

Abstract

Synthetic hydroxyapatite in a fine particulate dispersion has been used previously for the removal of Cd²⁺ cations from dilute aqueous solutions. In the present work the flocculation of these hydroxyapatite particulates was examined with and without the presence of Cd²⁺ ions by applying the conventional inorganic flocculents ferric chloride and aluminum sulfate. An optical technique was applied in order to monitor the flocculation dynamics of the dispersed particles, complemented by electrophoretic and turbidity measurements. The relative size of aggregates formed during flocculation, expressed as a “flocculation index,” could be continuously measured by this technique. Results indicated that the flocculation index provided important information about flocculation mechanisms. The main parameters examined included flocculent dose, solution pH, and mixing intensity. The optimum conditions for efficient flocculation were determined.     

新型两性聚合物絮凝剂的反相乳液法制备及性能研究

通过反相乳液法合成了一系列两性共聚物Poly(AM-DMPS),并研究了该两性共聚物对黏土的絮凝效果,结果发现,该两性共聚物对黏土有较好的絮凝效果,同时对絮凝现象进行了机理探讨.     

羧甲基壳聚糖净化海水的试验研究

用改性壳聚糖(羧甲基壳聚糖)作絮凝剂在室温(25℃)下对海水进行絮凝处理,研究了絮凝剂投加量、pH值和搅拌条件对絮凝处理效果的影响,并确定了适宜的操作条件:絮凝剂投加量范围为25～30mg/L,pH值范围为5～7,快速搅拌转速400r/min,时间90s,慢速搅拌转速60r/min,时间20min。在优化絮凝条件下浊度、化学耗氧量(CODMn)和总磷(TP)的去除率分别达72.6%、53.9%和40.0%。将羧甲基壳聚糖与壳聚糖对海水的絮凝净化效果进行了对比分析,结果表明,羧甲基壳聚糖对海水的絮凝效果相对壳聚糖有了较大提高,浊度和CODMn去除率明显提高,投加量适用范围更宽。