两性生物基絮凝剂制备及其处理造纸废水性能评价

本研究以壳聚糖季铵盐(HTCC)和羧甲基纤维素(CMC)为原料,通过戊二醛交联,制备了一种两性生物基絮凝材料(HTCC-g-CMC)。采用傅里叶变换红外光谱、热重分析对HTCC-gCMC进行表征,并将其应用于高岭土悬浊液和OCC造纸废水的絮凝处理以评价其絮凝性能。结果表明,HTCC与CMC通过缩醛反应成功合成了具有阴阳离子两性的HTCC-g-CMC;当pH值为4时,不添加PAC,HTCC-g-CMC絮凝高岭土悬浊液最小浊度为42. 1 NTU,当pH值分别为6、10时,在添加PAC的条件下,HTCC-g-CMC絮凝高岭土悬浊液最小浊度为2. 5、4. 5 NTU;将HTCC-g-CMC和商业APAM、CPAM对造纸废水直接进行絮凝处理,当用量为12 mL时,废水的浊度和CODCr去除率分别为88. 7、81. 2、35. 6 NTU和66. 2%、63. 6%、70. 0%,表明HTCC-g-CMC絮凝在浊度和CODCr去除率方面与商业PAM的效果相当。     

新闻纸造纸过程水回用处理工艺初探(Ⅱ)--超滤处理工艺参数的优化研究

对超滤法处理造纸过程水进行了工艺参数的优化研究.结果表明:在最佳操作条件下,浊度的去除率在98%以上,UV280降低了65.19%,出水的浊度值在1.0NTU以下,UV280值在1.60以下,很大程度上提高了高级回用的可能性.     

生物强化活性炭滤床深度处理造纸过程水的实验研究

以生物活性炭滤床装置对某造纸集团造纸过程水溶解氧气浮池出水的上清液进行回用深度处理试验。经过近100d运行的试验结果表明:在装置稳定运行时,生物活性炭工艺对造纸过程水的浊度、UV280、电导率的去除率达分别达到77.6%、78.1%、45.7%,出水浊度、UV280、电导率分别低至2.3NTU、0.7、1850μs/cm,证明生物活性炭滤床工艺在造纸过程水回用深度处理中能取得较好的处理效果。     

化学絮凝法在造纸白水处理中的应用

造纸白水用絮凝剂处理后CODCr、浊度去除明显,通过对比聚合碱式氯化铝(PAC)、聚合硫酸亚铁(PFS)、聚硅硫酸铝(PASS)3种不同的絮凝剂与助凝剂阳离子聚丙烯酰胺(PAM)配合处理造纸白水的结果发现,PASS絮凝效果最佳.研究表明,PASS与PAM配合处理白水的最佳条件:PASS用量100 mg/L,PAM用量2 mg/L,pH值7.0,在最佳絮凝条件下,CODCr、浊度的去除率分别为93%、98.2%.     

聚醚酮膜超滤深度处理造纸过程水的试验

对聚醚酮膜超滤法深度处理造纸过程水进行了试验研究。结果表明,超滤操作条件为:压力0.25MPa,水温30℃,搅拌速度60r·min-1时,聚醚酮超滤膜(PEK-20000)超滤出水的浊度为0.153NTU,UV280为1.17,去除率分别为96.8%和63.4%,满足造纸过程水回用对悬浮物和胶体物质的要求,且膜通量较高,为92.3L·(m2·h)-1。     

OS/PD复合物的制备及其对箱纸板生产造纸废水的絮凝处理

研究芭蕉芋氧化淀粉/聚二甲基烯丙基氯化铵(OS/PDADMAC)复合物对箱纸板生产造纸废水的絮凝作用效果。考察了OS羧基含量、PD分子量及组分配比等对絮凝效果的影响;并采用表观黏度测定、紫外光谱(UV)及胶体滴定探讨了OS与PD的复合作用及OS/PD复合物的絮凝机理。结果表明:OS3/PD2复合物对造纸废水絮凝效果最好,在w(OS):w(PD)为7:3,用量为100 mg·L-1絮凝条件下,浊度去除率达91%;OS羧基含量、PD分子量影响复合物的絮凝效果。     

细菌纤维素絮凝材料制备及其处理造纸废水性能研究

以醋酸杆菌构建分泌细菌纤维素(Bacterial Cellulose,BC)的菌种体系,通过优化发酵培养工艺和化学改性条件,制备BC絮凝材料。再通过优化混凝工艺,评价其对造纸废水的混凝处理能力。结果表明,制备的BC絮凝材料具有良好的三维网状结构,其羧基含量显著增加。通过Zeta电位检测表明该BC絮凝材料为阴离子型;且该材料对造纸废水平均浊度去除率可达94.6%,具有优良的混凝沉淀能力。     

膜分离技术深度处理造纸废水的研究

以二级生化处理后的造纸废水为研究对象,探讨了絮凝沉淀预处理和膜分离技术深度处理造纸废水的最佳工艺条件。研究结果表明,在阳离子聚丙烯酰胺添加量1.5 mg/L、聚合氯化铝铁添加量150 mg/L的条件下进行絮凝预处理时,絮凝效果能达到超滤膜进水要求。超滤膜操作压力控制在0.04～0.10 MPa、膜通量在12～17 L/h时,膜处理性能较好。废水经过超滤、纳滤和反渗透处理后,电导率降到12 μS/cm左右,TDS去除率达98%左右,COD_Cr去除率达90%以上,废水浊度已检测不到,完全达到生产回用水质标准。     

阳离子高分子絮凝剂的制备及在造纸废水中的应用

选择丙烯酰胺(AM)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)为主要单体,在适当的条件下进行反相乳液聚合,得到了特性粘度为800～1000 mL/g、阳离子度为25%～50%(摩尔)的阳离子型高分子质量的P(DMC-AM).将P(DMC-AM)乳液用于蒸煮黑液污(废)水的絮凝实验,CODCr去除率可达90%以上,透光率接近100%;通过扫描电镜观察经处理后的造纸中段废水絮凝物可以发现,絮凝后的纤维吸附紧密、交叉网状结构明显,说明其用作造纸废水絮凝剂具有十分显著的效果.     

加核絮凝法处理草浆造纸废水的工艺优化研究

草浆造纸废水成分复杂。拟研究一种以加核絮凝法作为主要工艺单元的组合工艺处理草浆造纸废水,本研究中仅对加核絮凝法进行工艺优化研究。首先设定参数,采用单因素法对加核絮凝工艺处理废水参数进行优化,试验结果表明,最优参数为:絮凝核材料沸石粒径100目,CTMAB(十六烷基三甲溴化铵)絮凝剂用量为25mg/L;处理草浆造纸废水效果较为明显,CODcr去除率可达80%。其次,考虑到成本问题,进行了沸石再生研究,试验结果表明,采用再生沸石不仅可以降低处理成本,而且对处理效果影响不大。     

Oxidation of Lard at Low Temperatures

In the introductory part the main factors are discussed which could cause the anomaly and in some cases even reverse course of the temperature dependence for oxidation of lipids. The experimental work demonstrates that the velocity of oxidation expressed by peroxide value increases in the row: I. lard; 2. lard + water + protein; 3. lard + water + carboxymethylcellulose (CMC); 4. lard + water + dextrose + CMC; 5. lard + water + protein + haemoglobin. As for the influence of NaCl can be stated that the addition has a pronounced proxidative effect in samples B (lard + water + CMC), C (lard + water + dextrose + CMC) and E (lard + water + protein + haemoglobin). As for the temperature dependence of oxidation can be stated that samples A (lard) and D (lard + water + protein) show little influence, samples E (lard + water + protein + hemoglobin) shows a picture normal for fat containing foods, while samples B (lard + water + CMC) and C (lard + water + dextrose + CMC) show the complex picture found by some authors in cured meat.     

不同浸泡方法对绿豆吸水特性的影响

为研究浸泡方式对绿豆软化处理的影响,采用不同温度条件浸泡、超声波和微波辅助浸泡处理、化学法辅助浸泡处理以及酶法辅助浸泡处理绿豆,考察不同方法对绿豆浸泡时吸水率、体积膨胀率的影响,同时采用扫描电子显微镜观察绿豆内部微观结构,并对其吸水动力学进行初步研究。结果表明,随着浸泡时间延长及温度提高,绿豆吸水率及体积膨胀率呈现增长态势直至饱和,但随着温度的升高,绿豆的饱和吸水率明显降低,不同浸泡处理方式的饱和吸水率及膨胀率不同。4种浸泡软化方法的吸水动力学方程为:1)不同温度条件浸泡:y_(20)=0.056x+0.002(R~2=0.945,20℃)、y_(40)=0.235x+0.085(R~2=0.978,40℃)、y_(60)=1.057x+0.332(R~2=0.983,60℃);2)超声波和微波辅助浸泡处理:y_u=0.182x+0.001(R~2=0.988,超声波)、y_m=0.116x+0.081(R~2=0.982,微波);3)化学法辅助浸泡处理:y_a=0.029x+0.051(R~2=0.963,乙酸)、y_(sb)=0.036x+0.027(R~2=0.838,碳酸氢钠)、y_(sc)=0.057x+0.054(R~2=0.957,碳酸钠);4)酶法辅助浸泡处理:y_c=0.122x+0.051(R~2=0.999,纤维素酶)、y_h=0.101x+0.103(R~2=0.854,半纤维素酶)、y_p=0.098x+0.002(R~2=0.990,果胶酶)。绿豆吸水动力学研究结果表明,物理、化学辅助浸泡处理均能提高绿豆的吸水速率,超声波、酶法辅助浸泡处理能显著缩短浸泡时间。     

Effect of Electrolyzed Water for Reduction of Foodborne Pathogens on Lettuce and Spinach

ABSTRACT:  The ability of electrolyzed water (EW) to inactivate foodborne pathogens on the surfaces of lettuce and spinach was investigated. Lettuce and spinach leaves were inoculated with a cocktail of 3 strains each of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and treated with acidic electrolyzed water (AC-EW), alkaline electrolyzed water (AK-EW), alkaline electrolyzed water followed by acidic electrolyzed water (sequential treatment, AK-EW + AC-EW), deionized water followed by acidic electrolyzed water (sequential treatment, DW + AC-EW), and deionized water (control, DW) for 15, 30 s, and 1, 3, and 5 min at room temperature (22 ± 2 °C). For all 3 pathogens, the same pattern of microbial reduction on lettuce and spinach were apparent. The relative efficacy of reduction was AC-EW > DW + AC-EW ≈ AK-EW + AC-EW > AK-EW > control. After a 3-min treatment of AC-EW, the 3 tested pathogens were reduced below the detection limit (0.7 log). DW + AC-EW and AK-EW + AC-EW produced the same levels of reduction after 5 min when compared to the control. AK-EW did not reduce levels of pathogens even after a 5-min treatment on lettuce and spinach. Results suggest that AC-EW treatment was able to significantly reduce populations of the 3 tested pathogens from the surfaces of lettuce and spinach with increasing time of exposure.     

SEPARATION of CHOLESTEROL FROM BUTTEROIL USING QUILLAJA SAPONINS. II. EFFECTS of TEMPERATURE, AGITATION and CONCENTRATION of QUILLAJA SOLUTION

The separation of cholesterol from butteroil was achieved by various processes based on contacting it with aqueous solutions of Quillaja saponaria saponins followed by separation of the cholesterol-saponin complex. Alternative processes and controls studied were (1) Water Control (W): butteroil was contacted with pure water; (2) Reaction (R): butteroil was contacted with aqueous solution of saponins; (3) Adsorption Control (A): butteroil was contacted with water, diatomaceous earth was then added; (4) Reaction + Adsorption (R+A): diatomaceous earth was added to the Reaction medium (from 2); (5) Reaction + Washing (R+W): the aqueous phase resulting from Reaction (2) was discarded and pure water contacted with the fat. the last step in all the above processes and controls was the separation of the fat phase, after which analyses were made. ANOVA indicated that the Adsorption Control process did not yield any significant cholesterol reduction over the Water Control; all other processes resulted in significant cholesterol separation in the order R+A > R+W > R. the levels of cholesterol reduction achieved by the R, R+W, and R+A processes were significantly affected by the concentration of quillaja solution and temperature; the level of agitation had no significant effect over the range investigated. Quillaja powder residue was present in the fat phase after Reaction (2) but both adsorption and washing procedures significantly reduced it.     

Reduction of Salmonella enterica on alfalfa seeds with acidic electrolyzed oxidizing water and enhanced uptake of acidic electrolyzed oxidizing water into seeds by gas exchange

Alfalfa sprouts have been implicated in several salmonellosis outbreaks in recent years. The disinfectant effects of acidic electrolyzed oxidizing (EO) water against Salmonella enterica both in an aqueous system and on artificially contaminated alfalfa seeds were determined. The optimum ratio of seeds to EO water was determined in order to maximize the antimicrobial effect of EO water. Seeds were combined with EO water at ratios (wt/vol) of 1:4, 1:10, 1:20, 1:40, and 1:100, and the characteristics of EO water (pH, oxidation reduction potential [ORP], and free chlorine concentration) were determined. When the ratio of seeds to EO water was increased from 1:4 to 1:100, the pH decreased from 3.82 to 2.63, while the ORP increased from +455 to +1,073 mV. EO water (with a pH of 2.54 to 2.38 and an ORP of +1,083 to +1,092 mV) exhibited strong potential for the inactivation of S. enterica in an aqueous system (producing a reduction of at least 6.6 log CFU/ml). Treatment of artificially contaminated alfalfa seeds with EO water at a seed-to-EO water ratio of 1:100 for 15 and 60 min significantly reduced Salmonella populations by 2.04 and 1.96 log CFU/g, respectively (P < 0.05), while a Butterfield's buffer wash decreased Salmonella populations by 0.18 and 0.23 log CFU/g, respectively. After treatment, EO water was Salmonella negative by enrichment with or without neutralization. Germination of seeds was not significantly affected (P > 0.05) by treatment for up to 60 min in electrolyzed water. The uptake of liquid into the seeds was influenced by the internal gas composition (air, N2, or O2) of seeds before the liquid was added.     

营养冲调粥流化床干燥特性及动力学模型的建立

利用流化床干燥装置,对营养冲调粥（玉米、红豆、荞麦、燕麦和小米质量比为3.5∶3.0∶2.0∶0.7∶0.8,加水后经双螺杆挤压膨化制得）的流化床干燥特性进行实验研究,探讨干燥过程中不同风速、进风温度以及产品加工过程中的加水量对营养冲调粥干基水分质量分数和干燥速率的影响,得到了营养冲调粥流化床干燥的失水特性规律。根据实验数据建立营养冲调粥流化床干燥的动力学模型,并对模型进行统计检验。结果表明,经拟合得到营养冲调粥流化床干燥的最佳模型为Page模型,拟合方程为：ln（－ln MR）＝－4.064 63＋0.014 14T＋0.069 85v＋0.327 5H＋（0.570 96＋0.000 976 25T－0.009 68v－0.265 5H）ln t（T为进风温度/℃;v为干燥风速/（m/s）;H为原料加水量/%）,此方程能够较好地描述营养冲调粥的干燥过程,准确预测各阶段营养冲调粥的干基水分质量分数和干燥速率。     

蒸煮方式对熟制小龙虾尾肉解冻后品质的影响

采用4 种蒸煮方式（以冷水开始煮制（BC）、以沸水开始煮制（BB）、以冷水开始蒸制（SC）和以沸水开始蒸制（SB））对小龙虾进行熟制,然后将熟制小龙虾于－18 ℃冻藏30 d,再采用2 种解冻方式（静水解冻（thawing in still water,ST）和4 ℃低温解冻（low temperature thawing,LT））进行解冻,研究不同解冻和蒸煮方式对小龙虾肌肉品质的影响。以冷却至室温未经冻藏的熟制小龙虾肉为对照组。测定菌落总数、持水性、水分分布、质构特性、色度、硫代巴比妥酸反应物（thiobarbituric acid reactive substances,TBARs）值,并通过电子鼻分析和感官评价分析小龙虾肉的感官特性。结果表明：ST组中采用BC和SC蒸煮小龙虾肉的菌落总数最高,分别为4.26、4.43（lg（CFU/g））;ST组较LT组更易使小龙虾肉的水分流失,并且以冷水开始蒸煮（BC和SC）的小龙虾肉持水性优于以沸水开始蒸煮（BB和SB）的小龙虾。感官评价与质构分析的结果表明,以沸水开始蒸煮的小龙虾肉感官品质更优。与对照组相比,ST与LT组小龙虾肉亮度值、黄度值（b*）增大,红度值减小,ST组中BC、BB、SC、SB方式蒸煮小龙虾肉的b*分别为32.67、28.87、33.36、27.36,显著高于其他2 组;ST组比LT组氧化程度高,且以冷水开始蒸煮的小龙虾肉脂肪氧化程度大于以沸水开始蒸煮的小龙虾。2 种解冻方式的小龙虾肉气味差异明显,冷、热水蒸煮对小龙虾的气味影响较大。     

SEPARATION of CHOLESTEROL FROM BUTTEROIL USING QUILLAJA SAPONINS. 1. EFFECTS of PH, CONTACT TIME and ADSORBENT

The technical feasibility of separating cholesterol from butteroil by contacting it with aqueous solutions of Quillaja saponaria saponins followed by separation of the cholesterol-saponin complex was studied. Alternative processes and controls compared were (1) Water Control (W): butteroil was contacted with pure water; (2) Reaction (R): butteroil was contacted with aqueous solution of saponins; (3) Adsorption Control (A): butteroil was contacted with water, diatomaceous earth was then added; (4) Reaction + Adsorption (R+A): diatomaceous earth was added to the Reaction medium (from 2); (5) Reaction + Washing (R+W): the aqueous phase resulting from Reaction (2) was discarded and pure water contacted with the fat. the last step in all the above processes and controls was the separation of the fat phase where cholesterol was determined. Statistical analysis indicated that the Adsorption Control did not yield any significant cholesterol reduction over the Water Control, while all other processes gave significant reduction. the order of cholesterol separation observed was R+A > R+W > R. the levels of cholesterol reduction were significantly affected by pH of quillaja solution and amount of adsorbent used; the time of contact with quillaja solution had no significant effect over the range investigated. These results indicate the technical feasibility of reducing the cholesterol levels of butteroil using food grade quillaja saponins.     

低频电场冰温保鲜对虾的水分迁移规律及品质变化的影响

为探明低频电场延长冰温保鲜对虾货架期的可行性。在冰温基础上施加低频电场（LFEF+冰温）保鲜对虾,监测贮藏期间对虾的菌落总数和总挥发性盐基氮（TVB-N）含量变化,分析微观结构变化,通过低场核磁共振（LF-NMR）技术探究虾肉和虾头的水分迁移和变化规律,并与常规冰温保鲜作对照。结果表明:贮藏第9 d,LFEF+冰温组的菌落总数和TVB-N含量开始表现出显著低于对照组的趋势（P<0.05）;第12 d后,LFEF+冰温组的菌落总数比对照组低一个数量级;其TVB-N含量在第11 d比对照组显著低36%（P<0.05）,货架期可达13 d以上。相比对照组的松散结构,LFEF+冰温组的虾肉微观结构变化程度明显较小。LF-NMR结果表明,低频电场从第7 d开始明显抑制冰温保鲜对虾虾头部位不易流动水向自由水的迁移,MRI成像可见水分扩散较慢。虾肉的腐败速率则低于虾头,LFEF+冰温组虾肉15 d内未出现明显的水分迁移。低频电场有利于延缓冰温保鲜期间对虾的腐败,延长货架期3~5 d。     

Dietary and waterborne mercury accumulation by yellow perch: a field experiment

It is well accepted that the majority of monomethylmercury (MMHg) in fish originates in their food; however, the additional contribution of water as a source to fish MMHg levels remains unclear. We used isotope enriched mercury (Hg) in a controlled field experiment to quantify the uptake of Hg from ingested and aqueous sources by young-of-year yellow perch (Perca flavescens). Water and zooplankton from a lake that had received (202)Hg-enriched additions (called spike Hg) for 7 y during a whole-ecosystem loading study (METAALICUS) provided natural, low-level Hg exposure. We achieved separation of exposure pathways by housing perch in one of four treatments: clean water + clean food; clean water + Hg spiked food; Hg spiked water + clean food; Hg spiked water + Hg spiked food. Fish accumulated MMHg directly from water, and this source accounted for at least 10% of MMHg in fish during the 27-d trial. Accumulation of spike Hg from water and food was additive, with food providing the majority of spike MMHg taken in by fish. Predictions from a bioenergetics model that excludes water as a source underestimated Hg in perch by 11%. This study illustrates the importance of acknowledging both food and water as sources of Hg to fish and suggests that aqueous Hg should be included as a source of contamination in bioaccumulation models and experiments.