无机填料在生物可降解塑料改性的应用进展

生物可降解塑料在实际应用时需要进行适当的改性,以提高其性能并降低成本。无机填料具有耐热性、可降解性及来源广泛等优点,可用于改性生物可降解塑料。无机填料与塑料基体极性差异较大,存在相容性的问题,不同种类的无机填料对生物可降解塑料的改性效果不同。文章概述常用的无机填料如滑石粉、碳酸钙、玻璃纤维等改性生物可降解塑料的研究进展,总结改性方法和作用机理。介绍生物可降解塑料在农业、食品包装、生物医药等领域的应用,对无机填料改性研究存在的问题进行分析。研究表明：无机填料对生物可降解塑料具有一定的成核效果,可显著改善生物可降解塑料的力学强度,使用时需注意无机填料的分散效果,此外,还需关注生物可降解塑料中无机填料的食品安全性。     

填料的改性及其表征

本文叙述了塑料填充改性用无机填料的主要品种及其作用,讨论了填料形状、粒径和表面结构对塑料改性的影响,提出了填料表面改性的主要技术、表征方法以及在塑料中的应用效果.     

填料在改性及其表征

本文叙述了塑料填充改性用无机填料的主要品种及其作用，探讨了填料形状，粒径和表面结构对塑料改性的影响，提出了填料表面改性的主要技术，表征方法以及在塑料中的应用效果。     

木质填料/热塑性塑料复合材料研究进展

介绍了木质填料的种类、用量、尺寸和塑料的种类对木质填料/热塑性塑料复合材料(WPC)性能的影响,综述了WPC的界面改性、增韧改性、加工改性和成型技术等方面的研究进展.     

非金属矿物填料在塑料中的应用与发展

介绍了非金属矿物填料的忠实用户——塑料行业在积极推广应用非金属矿物填料的现状,以及相应的最新涌现的有关塑料改性高新技术及理论,以及在这些理论指导下,产生的具有国内外先进水平的添加非金属矿物填料的改性塑料及发展趋势。     

塑料行业中非金属矿物填料应用现状与发展趋势

本文介绍了非金属矿物填料的忠实用户一塑料行业在积极推广应用非金属矿物填料的现状，以及相应的最新涌现的有关塑料改性高新技术及理论，和在这些理论指导下，产生的具有国内外先进水平的添加非金属矿物填料的改性塑料及它们的发展趋势。     

有机改性蒙脱土改性聚乳酸研究进展

聚乳酸是一种生物可降解高分子材料,具有较高的拉伸强度和良好的加工性能,但韧性较差。蒙脱土是一种层状硅酸盐纳米填料,具有高比表面积、低有效填充量、来源广泛和价格低廉等优点。采用有机改性蒙脱土纳米填料来改性聚乳酸,是一种提高聚乳酸性能的有效方法。综述了有机改性蒙脱土改性聚乳酸的4种方法,即直接共混改性聚乳酸、改性聚乳酸/韧性塑料共混物、改性聚乳酸/弹性体共混物、其他填料协同改性聚乳酸,介绍了其研究进展和存在的问题,并展望其前景。     

UHMWPE复合材料砂浆磨损性能研究

以还原Fe粉、SiO2、MoS2为填料对UHMWPE进行改性，采用模压烧结成型法制备了改性塑料，通过砂浆磨损性能的测试表明：改性塑料的砂浆磨损率均高于纯UHMWPE，加入还原Fe粉和MoS2填料后，改性塑料的磨损率曲线呈反“V”型：加入填料SiO2后，改性塑料的磨损率曲线近似呈“V”型，含量在6％时磨损率达到最小值，为5．66×10^-5mm^-2。     

改性UHMWPE塑料的磨粒磨损性能研究

本文采用还原Fe粉、SiO2、MoS2对UHMWPE进行填充改性,采用模压烧结成型法制备了改性塑料,分别测试了改性塑料的耐磨性、拉伸强度和硬度,根据扫描电镜照片分析了磨损表面形貌、拉伸断口形貌。实验结果表明:随着填料加入量的增加,磨粒磨损率呈现"V"型变化,其中添加SiO2的改性塑料最耐磨。三种填料都不同程度的降低了改性塑料的拉伸强度。添加二氧化硅和还原Fe粉会使材料的邵氏硬度有所提高。     

表面改性塑料填料流体力学及传质性能研究

采用新的塑料波纹填料改性方法,有效改善填料成膜性,与同等条件下商业填料进行对比。采用氧解析实验,在直径190 mm的有机玻璃塔内,液相喷淋密度10—36 m3/(m2·h),F因子0.2—3(m/s)·(kg/m3)0.5的实验条件下测定了改性填料及商用填料的流体力学及传质性能。实验结果表明:当液体喷淋密度为10,24,36 m3/(m2·h)时,在相同的F因子下,改性填料的液相传质单元高度Ho L较商用填料分别降低了29.50%,23.00%以及23.95%,同时改性后压降也相应为商用填料的85.37%,89.71%和88.35%。表明该改性方法在低喷淋密度下对塑料填料性能提升显著。此外,对实验填料的Ho L、压降进行了关联,采用狭通道液膜波动理论对填料塔内部液泛进行了探讨,为塑料填料的工业应用提供了设计基础。     

磁致物理化学生物效应及其在废水生物降解中的应用

对磁化所产生的物理、化学、生物三方面的效应进行了分析与综述,展望了其在废水生物降解中的应用。在废水生物降解处理过程中,利用磁致物理效应可提高溶解氧的浓度和嗜磁菌的密度,增加污染物、降解菌和氧的接触几率,强化体系中物质的扩散与传递;磁致化学和生物效应还可诱导微生物酶的合成和酶活,加快酶反应。新型活性磁种生物填料(同时结合生物亲和、亲水改性),可使微生物挂膜启动、新陈代谢以及废水的生物接触氧化降解过程更加容易且高效。最后指出生物亲和亲水活性磁种填料的研制和应用是生物接触氧化水处理技术的发展方向。     

Open-cell polyvinylidene fluoride foams as carriers to promote biofilm growth for biological wastewater treatment

This article reports the design and fabrication of open-cell polyvinylidene fluoride (PVDF) foams as carriers that can promote biofilm growth and organic removal efficiency for biological wastewater treatment in attached growth bioreactors. Open-cell PVDF foams were fabricated by a manufacturing approach that integrated compression molding and particulate leaching. PVDF carriers were structured with two governing factors of leaching agent types (e.g., sodium chloride [NaCl] and sodium acetate [NaOAc]) and contents (e.g., 80 and 90 wt%). Open-cell PVDF foams possessed high porosity and high protected surface area (i.e., more than ×10 to ×20 of the areas of commercialized carriers), which promoted biofilm growth in these carriers. As a successful advantage, PVDF carriers used in the moving bed biofilm reactors (MBBR) were entirely covered by biofilm in both interior and exterior parts without clogging. This provides strong evidence of the bacterial compatibility of the fabricated open-cell PVDF foam carriers. Moreover, the specific morphology of the PVDF carriers in this article provided superior biofilm protection from the detachment in MBBR. Experimental results revealed that PVDF open-cell foams fabricated by 80 wt% of NaCl demonstrated higher mechanical strength with an organic removal efficiency of 77% ± 7% in the corresponding bioreactor containing them.     

Three-Dimensional Stratification of Bacterial Biofilm Populations in a Moving Bed Biofilm Reactor for Nitritation-Anammox

Moving bed biofilm reactors (MBBRs) are increasingly used for nitrogen removal with nitritation-anaerobic ammonium oxidation (anammox) processes in wastewater treatment. Carriers provide protected surfaces where ammonia oxidizing bacteria (AOB) and anammox bacteria form complex biofilms. However, the knowledge about the organization of microbial communities in MBBR biofilms is sparse. We used new cryosectioning and imaging methods for fluorescence in situ hybridization (FISH) to study the structure of biofilms retrieved from carriers in a nitritation-anammox MBBR. The dimensions of the carrier compartments and the biofilm cryosections after FISH showed good correlation, indicating little disturbance of biofilm samples by the treatment. FISH showed that Nitrosomonas europaea/eutropha-related cells dominated the AOB and Candidatus Brocadia fulgida-related cells dominated the anammox guild. New carriers were initially colonized by AOB, followed by anammox bacteria proliferating in the deeper biofilm layers, probably in anaerobic microhabitats created by AOB activity. Mature biofilms showed a pronounced three-dimensional stratification where AOB dominated closer to the biofilm-water interface, whereas anammox were dominant deeper into the carrier space and towards the walls. Our results suggest that current mathematical models may be oversimplifying these three-dimensional systems and unless the multidimensionality of these systems is considered, models may result in suboptimal design of MBBR carriers.     

The Complex Mechanism of the Salmonella typhi Biofilm Formation That Facilitates Pathogenicity: A Review

Salmonella enterica serovar Typhi (S. typhi) is an intracellular pathogen belonging to the Enterobacteriaceae family, where biofilm (aggregation and colonization of cells) formation is one of their advantageous traits. Salmonella typhi is the causative agent of typhoid fever in the human body and is exceptionally host specific. It is transmitted through the fecal–oral route by consuming contaminated food or water. This subspecies is quite intelligent to evade the innate detection and immune response of the host body, leading to systemic dissemination. Consequently, during the period of illness, the gallbladder becomes a harbor and may develop antibiotic resistance. Afterwards, they start contributing to the continuous damage of epithelium cells and make the host asymptomatic and potential carriers of this pathogen for an extended period. Statistically, almost 5% of infected people with Salmonella typhi become chronic carriers and are ready to contribute to future transmission by biofilm formation. Biofilm development is already recognized to link with pathogenicity and plays a crucial role in persistency within the human body. This review seeks to discuss some of the crucial factors related to biofilm development and its mechanism of interaction causing pathogenicity. Understanding the connections between these things will open up a new avenue for finding therapeutic approaches to combat pathogenicity.     

固体表面生物膜结构特征与控制技术研究进展

固体表面附着的微生物膜往往具有很高的耐受性,难以清除并严重损害管道和设备。研发高效、生态友好的生物膜控制技术成为工业水处理的一个重点课题。通过阐述生物膜空间结构和物理化学特征,探讨了运用化学和生物技术处理生物膜的作用机制和效果。通过分析各种生物膜控制方法的研究进展,指出了未来管道生物膜控制技术的主要发展方向。     

不同填料在序批式生物膜反应器中的应用研究

填料是序批式生物膜反应器(SBBR)的重要组件,作为微生物在反应器中的载体,影响着生物的生长繁殖以及脱离进程,填料的性能还直接制约着处理效果.本文详述7种不同填料的特点和它们的运行效果,阐述了填料在SBBR工艺中的应用实例,讨论了适用于污废水处理的填料形态,为进一步开发出新型的性能更为良好的生物处理填料提供了研究基础.     

不同填料的厌氧氨氧化污泥挂膜性能比较

向厌氧氨氧化反应器内投加填料形成生物膜有利于污泥的持留,然而有关填料本身的不同特点对厌氧氨氧化生物膜生长影响的报道较少。将两种不同密度的悬浮塑料填料和两种不同密度的海绵填料置于同一反应器内,进行厌氧氨氧化污泥的挂膜,结果发现海绵填料的单个填料氨氮平均去除速率和亚硝态氮平均去除速率整体高于悬浮塑料填料,所挂污泥的EPS含量整体也高于悬浮塑料填料,并且挂膜速度也相对较快。在挂膜30 d后,单个小密度海绵填料便可检测出氨氮和亚硝态氮去除速率,且Δ（NO₂^--N）/（NH₄⁺-N）值接近1.32。在挂膜105 d后,单个小密度海绵填料的氨氮平均去除速率为0.123 mg·L^-1·h^-1,亚硝态氮平均去除速率为0.160 mg·L^-1·h^-1,值为1.30,最为接近理论值1.32,厌氧氨氧化活性为最佳,并且其所挂污泥的厌氧氨氧化菌丰度值在4种填料中最大,为1.73×10¹⁰ copies·（g dry sludge）^-1,总体来看小密度海绵填料的挂膜效果更好。     

新型好氧生物膜过滤器的应用研究

采用新型好氧生物膜过滤器对污水进行深度处理，中试结果表明，该过滤器能有效地降低污染水源和污水中的CODCr、BOD5、NH3－N和SS等，使出水水质能够满足工业回用水的要求，有显著的社会和经济效益。     

Characteristics of polyurethane (PU) foam plastics bio-carrier modified by chemical oxidation-surface covering with iron ion

采用化学氧化-铁离子覆盖改性方法对普通聚氨酯泡沫塑料填料进行改性,研究改性前后填料的表面特性、挂膜速度、生物膜量以及废水处理等性能。结果表明,改性填料表面的疏水性基团C—C、C—H比例下降了15.81%,亲水性基团C—O比例增加了16.17%,填料表面与蒸馏水的动态接触角减少了10.46°,其表面粗糙度以及亲水性提高。与未改性填料相比,改性填料生物膜量提高60%,生物膜平均每天生长量提高50%,但其生物膜脱氢酶活性并未明显提高。挂膜初期改性填料的COD和氨氮去除效果明显占优,挂膜完成后,改性填料对氨氮去除率比未改性填料高10%。     

化学氧化-铁离子覆盖改性聚氨酯泡沫塑料填料的特性

采用化学氧化-铁离子覆盖改性方法对普通聚氨酯泡沫塑料填料进行改性,研究改性前后填料的表面特性、挂膜速度、生物膜量以及废水处理等性能。结果表明,改性填料表面的疏水性基团C—C、C—H比例下降了15.81%,亲水性基团C—O比例增加了16.17%,填料表面与蒸馏水的动态接触角减少了10.46°,其表面粗糙度以及亲水性提高。与未改性填料相比,改性填料生物膜量提高60%,生物膜平均每天生长量提高50%,但其生物膜脱氢酶活性并未明显提高。挂膜初期改性填料的COD和氨氮去除效果明显占优,挂膜完成后,改性填料对氨氮去除率比未改性填料高10%。