聚硅硫酸铝絮凝剂的制备及其性能研究

采用硅酸钠、硫酸铝等为原料,制备了聚硅硫酸铝（PSAS）絮凝剂,并以印染废水为对象对其絮凝效果进行了研究。主要考察了在符合工业生产的条件与效益前提下,SiO2浓度、Si/Al物质的量的比、PS的活化时间、PS与PAS聚合后的熟化温度、聚硅酸（PS）与聚硫酸铝（PAS）的聚合pH值、污水pH值等因素对产品絮凝效果的影响。结果表明,Si/Al物质的量的比为1.0,SiO2浓度为1.0%,聚硅酸（PS）的活化时间为2 h,PS与PAS聚合后的熟化温度为50℃,聚合pH值为2.0,污水pH值为7.0条件下制备的聚硅硫酸铝对废水絮凝效果最好,废水的COD去除率达到94.3%。     

聚合氯化铝的盐基度与混凝性能关系研究

用三氯化铝滴碱法和铝酸钙酸溶一步法,分别制备了纯聚合氯化铝(PAC)和含钙的聚合氯化铝(CaPAC),对两种聚合铝的盐基度、铝的形态分布、混凝性能等进行了对比研究.采用Ferron逐时络合比色法对具有不同盐基度的PAC、CaPAC中的Ala、Alb和Alc形态分布进行了分析检测,并用烧杯试验方法考察了PAC、CaPAC对模拟水样和实际水样的混凝除浊性能.结果表明,PAC、CaPAC在对不同水样进行混凝处理后,水中余浊随两种聚合铝盐基度的增加而降低,余浊与盐基度表现出较好的相关性;在相同加药量条件下,CaPAC混凝除浊效果略好于PAC.另外,研究表明,Alb或Alc的形态分布与混凝除浊性能之间,未表现出明显的相关性.     

新型高分子絮凝剂聚硅酸硫酸铝的制备和性能研究

聚硅酸硫酸铝(PSAS)是一类性能优良的无机高分子絮凝剂.以水玻璃、硫酸铝、硫酸为原料合成了PSAS絮凝剂,探讨了反应物浓度、反应温度、反应时间、pH值、Al3+与SiO2物质的量比对产品PSAS制备及混凝脱色性能的影响.在pH=5.0～5.5的弱酸性介质中,PSAS最佳合成条件是SiO2的浓度为2.0%～3.0%,温度为20～30℃,Al3+与SiO2物质的量比为1.0.对染料废水的混凝试验表明产品的絮凝脱色性良好,脱色率≥97%,C0D去除率≥80%.该絮凝剂与其它无机絮凝剂相比,在降低色度、悬浮物、C0D方面效果显著.     

高浓度聚铝硅的制备及其混凝性能

采用稳定高浓度偏铝酸钠,与硅酸钠、硫酸铝等合成得到3个系列共15个澄清稳定的高浓度聚铝硅(HPASS)产品,pH为3.15～3.63,密度为1.20～1.28 g/mL,盐基度为65.90%～72.93%,Al2O3质量分数可达8.21%～10.84%.而Handv公司已工业化的产品PASS-100,Al2O3质量分数为10.1%,盐基度约为50%;国内Al2O3质量分数最高的PASS产品只能达到8%左右,盐基度为40%～60%.HPASS与PAC和聚铝铁(PAFC)的混凝性能对比实验发现,HPASS在投加质量浓度为7 mg/L(以Al2O3计)时,浊度去除率可达90%以上;当达到各自的最佳投加量时,HPASS处理后出水的浊度均《1 NTU.最低可达0.5 NTU,而PAC和PAFC分别为1.3、1.1 NTU.     

聚硅硫酸铝锌絮凝剂的制备及形态分析

以Na2SiO3、Al2(SO4)3和ZnSO4为原料,在常温常压下,制备出一种新型无机高分子絮凝剂-聚硅硫酸铝锌(PAZSS),以高岭土模拟废水为处理对象,探讨了Na2SiO3的摩尔浓度、Zn/Al摩尔比、(Al+Zn)/Si摩尔比对絮凝效果的影响,用X-射线衍射分析(XRD)和红外光谱分析等方法对该絮凝剂的结构及形貌进行了表征。结果表明,当Zn/Al摩尔比为1.0、(Al+Zn)/Si摩尔比为1.0时的去浊效果最佳,此时的去浊率可达到98%以上。且XRD和红外光谱分析的结果说明,向聚硅酸中引入的铝、锌离子与聚硅酸产生了一定相互作用,有利于链网状结构的生成,提高絮凝性能。并将PAZSS与聚硅硫酸铝(PASS)进行了比较,其处理效果远优于后者。     

聚硅硫酸铝处理黄浦江原水中试研究

用聚硅硫酸铝处理黄浦江原水进行中试研究,以解决冬季低温时硫酸铝混凝效果不佳的问题,结果表明:与硫酸铝相比,在相同投加量情况下,聚硅硫酸铝沉淀池出水浊度可降低50%;在投加量为硫酸铝1/2情况下,聚硅硫酸铝沉淀池出水的浊度仍低于硫酸铝沉淀池出水;残留的铝含量降低,而残留硅的含量没有增加,但投加聚硅硫酸铝会导致滤池水头损失增加。     

聚硅酸硫酸铝絮凝剂的制备及性能研究

本文尝试利用硫酸铝对活性硅酸进行改性,制备聚硅酸硫酸铝絮凝剂(PSAS)。研究表明,pH为3.0,铝硅摩尔比为1∶1时,制备的PSAS具有良好的稳定性和絮凝效果。其对pH约为7～9的中性浊水处理效果较好,在本次实验中最佳用量约为10 mg/L。其对高浊度实际水样及染料废水的净化和脱色能力较强,尤其对无机染料的脱色率约为99%。     

pH对聚合铝形态分布与混凝效果的影响

为了解聚合铝的混凝作用机理,以不同碱化度的聚合铝为混凝剂,考察了p H对聚合铝的形态分布、混凝效果及总溶解性残余铝的影响。结果表明,p H对聚合铝形态分布的影响十分明显,碱化度越低影响越显著;预制Alb和Alc在混凝过程中相对比较稳定,而低聚合度的Ala受p H影响显著;Ala在混凝过程中表现出阳离子的性质,电中和能力弱;与高Alb含量的聚合铝相比,高Alc含量的聚合铝出水浊度降低,但不能提高出水中的溶解性有机物去除率;总溶解性残余铝含量与混凝过程中Ala的含量有直接关联。     

冬季淮河水处理混凝剂的选择

以水玻璃、硫酸铝和硫酸为原料制备出了聚硅硫酸铝(PASS),制成品聚硅硫酸铝中Al2O3的质量分数为2.66%,SiO2的质量分数为2.54%,pH值为2.0~2.5。混凝试验表明:聚硅硫酸铝是一种适合处理低温低浊水的净水剂。在将冬季淮河原水的浊度从40NTU处理到4.31NTU时,需聚合氯化铝(以Al2O3计)4.10mg/L;而处理到相近浊度3.56NTU,仅需聚硅硫酸铝(以Al2O3计)2.20mg/L,絮凝效果聚硅硫酸铝好于聚合氯化铝。每处理1×103t冬季淮河水的混凝剂费用,聚硅硫酸铝为15.4元,聚合氯化铝为35.0元。     

新型高分子絮凝剂聚硅酸酸铝的制备和性能研究

聚硅酸硫酸铝（PSAS）是一类性能优良的无机高分子絮凝剂。以水玻璃，硫酸铝，硫酸为原料合成了PSAS絮凝剂，探讨了反应物浓度，反应温度，反应时间，pH值，Al^3 与SiO2物质的量比对产品PSAS制备及混凝脱色性能的影响，在pH=5.0-5.5的弱酸性介质中，PSAS最佳合成条件是SiO2的浓度为2.0%-3.0%。温度为20-30℃,Al^3 与SiO2物质的量比为1.0。对染料废水的混凝试验表明产品的絮凝脱色性良好，脱色率≥97%，COD去除率≥80%，该絮凝剂与其它无机絮凝剂相比，在降低色度，悬浮物，COD方面效果显著。     

聚合氯化铝铁的制备、使用及混凝机制研究

以氯化铝和氯化铁为原料制备出一系列不同铝铁物质的量比及碱化度的无机高分子混凝剂——聚合氯化铝铁（PAFC）,并应用于地表水的混凝处理过程。考察PAFC的混凝效能及产生的絮体特性,进而对其使用条件进行优化并分析混凝机制。结果表明,PAFC为多羟基桥连的铝铁聚合物,水解后发生电中和作用使胶粒脱稳,而后通过羟桥和氧桥联接产生架桥和卷扫沉淀作用,混凝效果优异。PAFC的pH适用范围较宽,但铝铁物质的量比对其水解过程影响较大,在铝铁物质的量比为7:1、碱化度为0.5、投加量为10 mg/L时,絮体的粒度及生长速度最大,此时浊度和UV₂₅₄的去除率分别达84.93%和78.52%。此外,正交实验的结果表明水力条件对PAFC的混凝效能影响显著,其最佳使用条件为：快搅时间为20 s、快搅速度为200 r/min、慢搅时间为15 min、慢搅速度为40 r/min。     

聚硅酸铝铁絮凝剂的制备及处理工业废水的实验研究

采用粉煤灰、工业废硫酸和硫铁矿渣为原料,通过自制的聚铁和聚铝,制备了不同Si/(Al+Fe)摩尔比的聚硅酸铝铁(PSAF)絮凝剂.实验结果表明:与传统无机盐絮凝剂相比,PSAF的絮凝效果较好,COD及色度去除率能达到78.62%和83.56%以上.实验得到PSAF最佳制备条件:Si/(Fe+Al)=1/20,Fe/Al...     

Characterization and catalytic behaviors of methylamine modified FAU zeolites

The methylamine (MA) modified FAU zeolites with 5.8 and 80 of silica alumina molar ratio were successfully prepared by the treatment of original FAU zeolites with MA. The obtained materials were investigated with diffuse reflectance infrared Fourier transform spectroscopy, X-ray diffraction, magic-angle spinning nuclear magnetic resonance, thermogravimetry, temperature-programmed desorption of CO₂ and NH₃ (CO₂-TPD and NH₃-TPD), nitrogen content analysis, and specific surface area analysis. The formations and thermal stabilities of different Si–N–C groups in the MA modified FAU zeolites were confirmed. The changing of aluminium species due to the interaction of MA and framework/extraframework aluminium (FAL/EFAL) in the modified samples was discovered. The acidity and basicity of the MA modified FAU zeolites were correlated to the hybrid aluminium species and variation of Si–N–C groups, respectively. The catalytic behaviors of the MA modified FAU zeolites were explored by Knoevenagel condensation reaction of benzaldehyde and malonic acid.     

聚硅酸氯化铝镁絮凝剂的制备及废水处理研究

将聚硅酸( Psi)、聚合氯化铝(PAC)和氢氧化镁浆料复合,制得了不同铝硅摩尔比和盐基度的聚硅酸氯化铝镁(PACSM)絮凝剂,并用于含油废水和造纸废水的处理,且与PAC、聚硅酸氯化铝(PACS)的处理效果进行了对比.结果表明,在n(Al)∶n(Si)为10～15时,PACSM对2种废水的浊度、色度和有机物的去处效率都较高,并且处理过后的水中残留的铝含量也较低;PACSM各方面处理效果都要好于PACS和PAC絮凝剂,而PACS絮凝剂又要好于PAC絮凝剂.     

Hydrolysis of aluminium on weakly acidic organic exchangers: Implications for phosphate adsorption

In contrast to its behaviour on soil clays and in aqueous solution, aluminium is more extensively hydrolysed between pH3 and 4.5 on organic exchangers because the weakly acidic carboxyl groups appear to act as sinks for the protons released by hydrolysis and polymerization of the Al(H₂O) ₆ ³⁺ ions. In consequence, the basicity (measured by the OH/Al mole ratio) of Al adsorbed on samples of acid peat, humic acid and Amberlite IRC-50 resin was closely correlated with the apparent pK_a of the acid groups. The amount of phosphate adsorbed depended not only on the amount of Al adsorbed but also on the basicity of the adsorbed Al. Phosphate and OH^– ions competed for Al on the exchange sites with the result that the P/Al mole ratio on the exchanger was inversely related to the basicity of the adsorbed Al. Once adsorbed, the Al was quite stable and P adsorption on the Al-exchanger was unaffected by a rise in pH from 4.5 to 6.4.     

Low temperature mullite forming pre-ceramic resins of high ceramic yield for oxide matrix composites

Monophasic mullite precursors, namely aluminosiloxanes were synthesized by a novel synthetic route, in which co-hydrolysis and condensation of aluminium tri secbutoxide and tetraethoxy silane was achieved in presence of con. HCl in a non-polar medium. Aluminosiloxanes were characterized by FT-IR, NMR, and elemental analyses. Spectral analysis confirms the presence of Si-O-Al bonds in all the samples and also validates the incorporation of more aluminium via Si-O-Al bonds with increasing Al/Si mole ratio in the precursor. These FT-IR and NMR data also attest the precursor level homogeneity in all the samples. The aluminosiloxanes are obtained as low viscous resins and are capable of giving high ceramic residue qualifying them as ceramic matrix precursors for CMCs. The effect of Al/Si ratio on the ceramic conversion was studied. All the precursors showed the formation of mullite at 1000 °C. This low temperature mullite formation is a key factor in developing oxide CMCs without fiber damage. The results obtained from the study show that the composition of the ceramic can be controlled between a silica rich mullite phase and near-stoichiometric mullite phase by suitably selecting the Al/Si monomer feed ratio of the precursors. This aspect provides a greater scope for designing application-specific ceramic matrices for space applications.     

聚硅酸铁钛絮凝剂制备及焦化废水混凝处理试验

制备无机-无机多元复合型絮凝剂聚硅酸铁钛,通过正交试验考察Fe∶Ti、(Fe+Ti)∶Si以及碱化度对混凝能力的影响,将其应用于焦化废水生化出水的混凝处理,并研究其对焦化废水中有机物的特性去除以及混凝过程中絮体粒径变化趋势。研究结果表明:配比为Fe∶Ti=7∶1、(Fe+Ti)∶Si=6∶1、碱化度=0.8的絮凝剂混凝能力较优;投加量为600 mg/L时,对焦化废水生化出水中浊度、DOC、COD_Cr和UV₂₅₄的去除率可以分别达到95.7%、24%、46.4%、36.1%,并且对其中长链羧酸、长链酰胺类以及类富里酸与酪氨酸类芳香性蛋白质有机物去除效果明显。     

Acidity and catalytic activity of the mesoporous aluminosilicate molecular sieve MCM-41

The acidity and catalytic properties of aluminosilicate mesoporous molecular sieves with the MCM-41 structure and bulk Si/Al ratios in the 10–60 range have been investigated. The incorporation of 4-coordinate aluminium into the structure of MCM-41 generates both BrØnsted and Lewis acid sites in amounts increasing with the degree of incorporation. However, the BrØnsted/Lewis acid population ratio is independent of the content of aluminium. The number and strength of acid sites generated are comparable to those of a pillared acid-activated clay and lower than in zeolite H-Y with Si/Al=3.65. Aluminosilicate MCM-41 is a moderate catalyst for the conversion of cumene which proceeds predominantly via catalytic cracking to propene and benzene. The sample of MCM-41 with the highest content of framework aluminium (Si/Al=10) has the largest number of BrØnsted acid sites and exhibits highest catalytic activity.     

聚硅酸硫酸铝铁的制备和应用研究进展

介绍了混凝剂聚硅酸硫酸铝铁(PAFSS)的制备方法和应用研究的新进展,讨论了PAFSS混凝剂的混凝作用机理及其稳定性。指出制备良好的聚硅酸硫酸铝铁混凝剂,关键因素是控制Al/ Fe/ Si的物质的量比、硅酸浓度、温度、pH和铝盐、铁盐的加入顺序。通过调节pH、控制二氧化硅浓度、向PAFSS中投加无水乙醇、正丁醇、丙酮等稳定剂,可以有效延缓PFASS混凝剂的凝胶速度,提高了其稳定性。此外,针对目前聚硅酸盐在应用中存在的问题,提出了今后的研究方向。