助留剂在造纸中的应用

介绍了纸料的絮聚原理及常见的助留助滤系统,分析了各种助留助滤系统的优点及适应范围。     

凹凸棒黏土助留助滤效果研究

探讨了凹凸棒黏土与阳离子聚丙烯酰胺(CPAM)组成的微粒助留助滤体系的助留助滤效果及相关机理,并与CPAM-膨润土助留助滤体系进行了比较。结果表明,高剪切处理后的凹凸棒黏土微粒解聚分丝、具有更好的分散性能,提高了助留助滤效果。当凹凸棒黏土微粒用量为0.4%、CPAM用量为0.05%时,处理后的凹凸棒黏土助留助滤效果与商品膨润土相当,抄造纸张的强度性能略好。用聚焦光束反射原理测定絮体弦长及其分布发现,处理后凹凸棒黏土的絮体弦长大于未处理凹凸棒黏土的絮体弦长,但小于商品膨润土的絮体弦长。     

阴离子树枝状聚酰胺-胺在有机微粒助留助滤体系中的应用

通过碱性水解将端酯基的半代树枝状聚酰胺-胺(Gn.5PAMAM)改性为外层基团为羧酸钠的阴离子树枝状聚酰胺-胺(A-Gn.5PAMAM),并通过红外光谱进行了结构表征。将A-Gn.5PAMAM作为有机阴离子微粒组分与星形阳离子聚丙烯酰胺(S-CPAM)及阳离子聚丙烯酰胺(CPAM)组成有机微粒助留助滤体系,系统地研究了该有机微粒体系对漂白旧报纸脱墨浆的助留助滤效果。结果表明,S-CPAM(CPAM)-(A-Gn.5PAMAM)有机微粒体系对纸料具有较好的助留助滤作用效果;高代数的A-Gn.5PAMAM对纸料小絮块的絮聚能力优于低代数产物;该有机微粒助留助留体系可以适应较宽的pH值范围,且抵抗高剪切作用的能力较强。研究同时表明,A-Gn.5PAMAM有机阴离子微粒与膨润土无机阴离子微粒具有很好的协同作用。     

纳米TiO2胶体多元复配体系对DIP的助留助滤研究

利用动态滤水实验,通过检测留着率和滤水时间来考察纳米TiO2胶体多元复配体系对脱墨浆(DIP)抄造新闻纸过程的助留助滤作用.结果表明,二元体系中,AmS(两性淀粉)-TiO2二元复配体系助留助滤效果最好,当纳米TiO2胶体用量0.20％和AmS用量0.5％时,其滤水时间是13s,其总留着率达到93.4％;在三元体系中,当CS(阳离子淀粉)用量0.4％、APAM(阴离子聚丙烯酰胺)用量0.01％和纳米TiO2胶体用量0.2％时的体系的滤水时间最小,为17s;当CS用量0.4％、CPAM(阳离子聚丙烯酰胺)用量0.01％和纳米TiO2胶体用量0.2％时总留着率最大,为97.5％.研究发现,纳米TiO2胶体多元体系具有好的助留助滤效果,淀粉系列因为具有三维结构,为纤维、DCS(溶解和胶体物质)的絮聚提供了更多的结合机会,而PAM(聚丙烯酰胺)系列主要通过桥联、电荷吸附以及补丁絮聚机理实现好的助留助滤效果.     

造纸法抄造烟草薄片助留助滤性能的研究

选取了壳聚糖、CGG、CPAM 3种助留助滤剂,分别研究了其对烟草薄片浆料Zeta电位、动态滤水和单程留着率、填料留着率以及对薄片抗张强度的影响,以期能够提高烟草薄片生产过程中的纸机运行性能、提高生产效率.研究结果表明3种助留助滤剂对浆料Zeta电位、助滤性能、留着性能的影响具有相似的规律壳聚檐＞CPAM＞CGG.壳聚糖用量达到0.6%时,其助留助滤性能基本能够满足纸机抄造系统的使用要求以及烟草薄片的性能要求,其用量继续提高会引起浆料的强烈絮聚,对抄纸过程和产品质量将产生不利影响;CGG和CPAM在较高用量时,浆料的絮聚并不显著,提高其用量,对浆料的助留助滤性能仍有提高的潜力.     

双氰胺甲醛缩聚物造纸助留助滤剂的制备及应用

以双氰胺、甲醛为原料制备双氰胺甲醛(DDF)缩聚物,并研究DDF用作造纸助留助滤剂的可行性。探讨DDF用量、浆料pH值、混合时间及DDF与填料碳酸钙添加顺序4个因素对浆料助留助滤性能的影响,并通过扫描电子显微镜对DDF和阳离子聚丙烯酰胺（CPAM）在纸张中的留着情况进行了对比。实验结果表明,当先加入用量0.03%的DDF、再加入20%碳酸钙、浆料pH值9、混合时间6~7 min时,浆料可获得较好的助留效果，但助滤效果不明显；扫描电子显微镜结果表明,碳酸钙和细小纤维在DDF作用下絮聚成体积较大的絮团，留着在纤维交织层中，从而提高了填料和细小纤维的留着率。     

纸张生产中高效的微粒助留助滤体系

拜尔化学公司已为造纸行业开发出一种新的微粒助留助滤体系。当使用这种新的Retaminol Syncro体系时，絮聚过程由化学方法控制，而不是像通常情况下借助机械剪切力的作用。二元体系保证快速而无任何问题地生成蒙脱石分散液和相当有效的助留助滤。它可广泛用于各种中性和碱性抄纸。     

阳离子淀粉/氢氧化铝二元助留体系的研究

由阳离子淀粉和氢氧化铝溶液组成的二元助留体系能引发纤维和填料的絮聚,形成结构致密而尺寸较小的细小纤维絮聚体,这大大提高了纸料的留着率和滤水性能。但这一助留体系助留助滤作用受使用条件(pH、加入量等)影响,本实验在实验室条件下,找出影响这一体系留着作用的主要影响因素。得出阳离子淀粉/氢氧化铝二元助留体系的最佳应用条件:淀粉量1.6%、硫酸铝用量1.5%、pH值为7、动态滤水转速500rpm、接触时间20s。     

用动态滤水仪探讨微粒助留体系絮聚机理

以CaCO3及经100目筛分得到的纤维为实验原料，设计了几种模型，用动态滤水仪(BRITTDDJ)探讨了CPAM／膨润土微粒助留体系的絮聚机理，并与CPAM单元助留体系的留着和抗剪切性能进行了比较。实验发现膨润土的主要作用是与吸附在纤维、细小组分上的CPAM之间产生强的连接键，从而产生絮聚；微粒助留体系比CPAM单元助留体系具有更好的留着和抗剪切性能。     

氢氧化镁铝胶体微粒助留影响因素探讨

双金属氢氧化物被广泛用于很多工业,氢氧化镁铝胶体由于其自身所带的强正电性和特殊的晶体结构,可以与阴离子聚丙烯酰胺复配应用到造纸湿部助留中,可以与纤维发生强烈的电荷中和絮聚吸附作用,能显著提高纤维的留着率.但是助留效果受到很多因素的影响,本文主要从氢氧化镁铝胶体助留实验过程中助剂加入次序,加入间隔的时间,剪切力和填料等方面对其影响进行探讨,更进一步优化氢氧化镁铝胶体助留实验条件.     

PEO辅助助剂对胶体悬浮液絮凝作用影响

以PEO/辅助助剂系统为絮凝系统，对PCC、瓷土和TiO2等三种胶体悬浮液进行絮凝实验，探讨了辅助助剂对胶体悬浮液絮凝作用的影响。结果表明，开环结构的辅助助剂的絮凝效果好，闭环结构的絮凝效果差。由于辅助助剂DEA和ACS带有阴电荷，因此呈阳电性的PCC絮凝最好。使用高阳电性的辅助助剂VBT1时，TiO2的絮凝效果最好。使用PEO/VBT2对三种胶体悬浮液进行絮凝，对瓷土的絮凝效果最好。总体上，瓷土胶体悬浮液最易絮凝。说明辅助剂的电荷密度和酚羟基的密度对胶体悬浮液的絮凝的重要性。     

BIOCHEMICAL ASPECTS OF YEAST FLOCCULATION AND ITS MEASUREMENT: A REVIEW

Factors affecting flocculation of brewing yeast, our current understanding of the process and traditional methods of assessing flocculence are discussed in this review. In spite of extensive study during the last two decades, a number of uncertainties and controversies regarding yeast flocculation still remain. This confusion is due in part to the polyploid or aneuploid nature of most brewing strains studied. At present, uncertainty exists as to the number of genes involved in flocculation as well as the nature and mode of action of the resulting gene products. Another restriction to our investigation of flocculation is the lack of a fundamental and standard test method. Along with a general discussion of yeast flocculation, this report will note conflicting reports concerning the influence of temperature, the effect of metal ions such as magnesium and barium, and the importance of the carboxyl and phosphate groups in yeast cell—cell interactions. As well, past and current methods employed for the assay of brewing yeast flocculation will be discussed.     

Mitochondrial Associated Yeast Flocculation ‐The Effect of Acetylsalicylic Acid

Mitochondrial function is generally accepted as important for expression of yeast flocculation. In this study, a correlation between mitochondrial activity and flocculation is demonstrated using the XTT reduction assay. The mitochondrial activity of strongly flocculent cells was higher than those of weakly flocculent cells and cells cultivated in the presence of acetylsalicylic acid. Furthermore, we show the first oxylipin‐containing flocculation binding sites on yeast cell surfaces using scanning electron microscopy. We propose that in addition to zymolectin‐mediated flocculation, oxylipin interactions may also play a role in yeast flocculation.     

壳聚糖对茶皂素水溶液絮凝工艺的研究

以壳聚糖为絮凝剂，研究了茶皂素水溶液的絮凝工艺，考察了壳聚糖加入量、助剂加入量和絮凝时间对絮凝效果的影响。通过正交试验得出最佳絮凝条件为：壳聚糖加入量5mL、助剂加入量5mL、絮凝时间4h。在最佳条件下验证试验，杂质去除率为34．33％，茶皂素损失率为5．64％。     

Yeast flocculation: kinetics and collision theory

Flocculent yeast cells have an absolute requirement for mechanical energy input in order for flocculation to occur. Flocculation is arrested by cessation of energy input. The initial rate of flocculation increases as the square of the cell concentration. There is a minimum shaking speed to initiate flocculation and thereafter the initial rate of flocculation increases exponentially with the shaking speed. The minimum shaking speed for flocculation to occur increases with pH value. Activation energy for flocculation, derived from Arrhenius-like plots, varies with pH value. We propose that activation energy is required to overcome mutual repulsion between charged yeast cells and allow flocculent bonds to be formed.     

PAFC与PAM复合絮凝剂处理泡菜废水

采用絮凝法对泡菜废水进行了絮凝烧杯试验,讨论了絮凝剂的选择、PAFC与PAM的不同用量、pH值以及温度对絮凝效果的影响,确定了絮凝剂处理废水的较佳絮凝条件。研究结果表明,PAFC用量90 mg/L,PAM用量60 mg/L,pH值为7,温度为35℃,在此条件下,泡菜废水处理率为:COD、NH3-N、TP去除率分别为83.9%、47%、92.5%。     

氢氧化镁的絮凝沉降规律

文章考察了采用氯化镁-氢氧化钠常温合成工艺制备的氢氧化镁在典型絮凝体系中的聚沉行为。实验结果表明:常温合成的氢氧化镁颗粒之间静电斥力较大,极难沉降;氯化亚铁和明矾对氢氧化镁无絮凝作用;淀粉和非离子型聚丙烯酰铵由于架桥效应可在一定程度上加速氢氧化镁的沉降;高聚合度阴离子型聚丙烯酰铵具有电荷中和与架桥双重功能,可使氢氧化镁的沉降体积及团聚粒径大幅度增加,聚沉效果显著提高。     

聚合硅酸硫酸铝的絮凝性能

研究了聚合硅酸硫酸铝对高岭土悬浮液的絮凝性能.结果表明,聚合硅酸硫酸铝对高岭土悬浮液具有极好的絮聚作用,其絮凝效果与聚合硅酸硫酸铝的碱化度、加入量和高岭土悬浮液的pH值有关;其絮凝机理主要为吸附架桥与卷扫等作用.     

Identification of key constituents and structure of the extracellular polymeric substances excreted by Bacillus megaterium TF10 for their flocculation capacity

Extracellular polymeric substances (EPS), a complex high-molecular-weight mixture of polymers excreted by microorganisms and produced from cell lysis, may have a high bioflocculation activity. In this work, the EPS excreted from Bacillus megaterium TF10, which was isolated from a soil sample, were systematically characterized to give insights into the relationship between their specific constituents and structure with their flocculation capacity. The results of microscopic observation, zeta potential, and TF10 EPS structure analysis show that the bridging mechanism was mainly responsible for the flocculation of the TF10. The constituents with a large molecular weight (1037-2521 kDA) and functional groups had contributed to the flocculation. GC-MS and NMR analyses demonstrate that the polysaccharides had long chain composed of rhamnose as well as glucose and galactose with uronic acids, acetyl amino sugars, and proteins as the side chains. The proteins in TF10 had no flocculation ability because of their special secondary structure and molecular weight diffusion characters. The EPS from Bacillus megaterium TF10 were found to exhibit a high flocculation activity, and the polysaccharides in EPS, which have the structure of the long backbone with active side chains, were identified as the active constituents for the high flocculation activity.     

Lipid Turnover During Inverse Flocculation in Saccharomyces cerevisiae UOFS Y‐2330

In this study we uncovered that Saccharomyces cerevisiae UOFS Y‐2330 does not only demonstrate inverse flocculation, but is also characterised by two different lipid turnover patterns. During Flo1 phenotype flocculation, this yeast showed two neutral lipid accumulating stages (i.e. at 8 h and from 12 h). This is probably triggered by flocculation, which can be regarded as a survival mechanism where cells accumulate predominantly neutral lipids as a reserve energy source — a similar mechanism is probably operative when cells enter stationary growth. Contrary to Flo1 behaviour, this strain in NewFlo phenotype mode demonstrates only a single lipid accumulation phase i.e. when cells enter stationary growth, which coincides with increase in flocculation. In addition, an increase in phospholipids was experienced during active growth in both flocculation behaviours i.e. Flo1 and NewFlo probably as a result of active membrane production.