共查询到20条相似文献,搜索用时 15 毫秒
1.
Na-A zeolite was synthesized using oil shale ash (OSA), which is a solid by-product of oil shale proc- essing. The samples were characterized by various techniques, such as scanning electron microscopy, X-ray diffrac- tion and Brunaner Emmet Teller method. The batch isothermal equilibrium adsorption experiments were performed to evaluate the ability of Na-A zeolite for removal of Cu (II) from aqueous solutions. The effects of operating pa- rameters, such as concentration of copper solutions, adsorbent dosages, pH value of solutions and temperature, on the adsorption efficiency were investigated. The equilibrium adsorption data were fitted with Langmuir and Freundlich models. The maximum adsorption capacity of Na-A zeolite obtained from the Langmuir adsorption iso- therm is 156.7 mg.g-t of Cu (lI). The increase of pH level in the adsorption process suggests that the uptake of heavy metals on the zeolite follows an ion exchange mechanism. The batch kinetic data fit the pseudo-second order equation well. The thermodynamic parameters, such as changes in Gibbs free energy (AG), enthalpy (AH) and en- tropy (AS), are used to predict the nature of the adsorption process. The negative AG values at different tempera- tures confirm that the adsorption processes are spontaneous. 相似文献
2.
系统研究了油页岩渣合成沸石过程中NaOH浓度、熔融温度、晶化时间、晶化温度对沸石生成及其Cr6+吸附性能的影响. 结果表明,NaOH浓度和晶化时间主要影响沸石的种类;沸石对Cr6+的吸附率随其制备的熔融温度、晶化时间、晶化温度的增加有增大的趋势,但随NaOH浓度降低而增加;沸石对1 mg/L含铬模拟废水中Cr6+的最大吸附量为1.120 mg/g,吸附率达到89.6%. 考虑到成本,最佳合成条件为:NaOH浓度4.6 mol/L,熔融温度400℃,晶化时间72 h,晶化温度140℃. 相似文献
3.
4.
本试验以内蒙古锡林郭勒盟粉煤灰为原料,采用500℃低温碱融-水热法合成了4A分子筛,并加入了导向剂,有效减少了晶化时间.以4A分子筛的Ca2交换能力为指标,并运用XRD、SEM、FT-IR对生成的4A分子筛进行表征,通过正交试验对合成工艺进行了探究.结果表明:在500℃下碱融活化2h后,粉煤灰中的石英和莫来石晶体结构被完全破坏.原料配比为n(SiO2):n(Al2O3)=2.1,n(Na2O):n(SiO2) =2.2,晶化温度50 ℃,晶化时间30 h,在此条件下生成了纯净的4A分子筛,粒径约为2μm,对Ca2的交换能力为310 mg/g. 相似文献
5.
6.
本文考察了4M氢氧化钠水溶液和121℃条件下水热反应时间对粉煤灰合成产物的影响,用粉末X-射线衍射(PXRD)、扫描电镜(SEM)、差式扫描量热(DSC)以及热重(TG)等手段对产物进行了分析表征.Jade 6.0软件分析表明,粉煤灰水热反应合成了羟基方钠石,其晶胞参数为a=b=c=0.906 nm.随着水热时间的延长,合成羟基方钠石的结晶度和含量增加.合成产物呈表面粗糙的球状,粒度随水热时间延长而增大.热分析结果表明合成羟基方钠石中含有结晶水,其分子式为Na8Al6Si6O24 (OH)2·2H2O.粉煤灰400 min水热合成产物中的二水羟基方钠石纯度约为65.32%. 相似文献
7.
以吉林桦甸-公郎头四层油页岩为原料,以掺混SiO2的油页岩为对比样品,利用热重-红外联用仪考察了页岩灰对油页岩热解特性的影响,通过分析热解固相产物组成变化对热解失重及产物析出规律进行了研究. 结果表明,页岩灰对油页岩中的有机质和矿物质失重过程均有促进作用,当页岩灰或SiO2含量为83%时,在300~600, 600~750, 750~900℃三个加热温度区间内,掺混页岩灰样品比掺混SiO2样品的失重率分别提高1.92%, 3.39%和18.99%. 低温段有机质热解过程中CO2先于脂肪烃热解析出,且750℃后CO2析出峰仅出现在掺混页岩灰的样品中,应为油页岩中难分解的碳酸盐在页岩灰作用下加速分解及页岩灰中CaSO4与残炭反应共同作用所致. 相似文献
8.
P型分子筛在洗涤剂工业、石化工业、医药和环保工业等领域具有广泛的应用.为了探究粉煤灰制备P型分子筛过程中原料及产物的物相变化规律,用X射线多晶衍射仪(XRD)对粉煤灰、碱融产物及不同工艺参数条件下水热法合成出的产物进行了物相分析.XRD分析结果表明,在m(粉煤灰)∶m(碳酸钠)=1∶1.1、800℃煅烧2h的条件下,能充分活化粉煤灰中的莫来石、石英等惰性相,得到高化学活性前驱粉体,其主要成分为NaAlSiO4.在合成体系的n(SiO2)/n(Al2O3)=3.5、n(H2O)/n(Na2O) =45、n(Na2O)/n(SiO2)=1.3、无老化步骤、在95℃水热晶化时间为9h的条件下,获得的产物是纯净的P型分子筛.该法消耗了粉煤灰,实现了废物的资源化利用,同时获得了高附加值的产物P型分子筛. 相似文献
9.
10.
11.
油页岩灰填充母粒的研制 总被引:4,自引:0,他引:4
论述了油页灰的化学组成、物理性能和颗粒分布特性,介绍了油页岩灰填充母粒的制备方法及其在低填充量下的物理、力学性能、流变性能和断面形态。该填充母粒与碳酸钙填充母粒相比具有优异的耐老性能和较好的流动性,可广泛用于挤塑、注塑和像胶发泡制品。 相似文献
12.
《分离科学与技术》2012,47(14):2260-2274
The removal of phosphate from aqueous solution by the adsorption process using zeolite synthesized from fly ash was investigated in this study. The XRD patterns revealed that the major crystalline phase of the synthesized zeolite was gismondine. The phosphate immobilization capacity (PIC) increased significantly from 52.7 mg/g of fly ash to 102.9 mg/g of synthesized zeolite after conversion. The batch experiments were conducted to investigate the effect of pH, initial phosphate concentration, and adsorbent amount. The maximum adsorption capacity was obtained at the pH value of 7.0. The adsorption process followed Ho' pseudo-second-order model, and both liquid film and intra-particle diffusion were the rate-controlling step for the process. The adsorption equilibrium data had been analyzed by Langmuir, Freundlich, Radlich-Peterson, Koble-Corrigan, Tempkin, Dubinin-Radushkevich, and Generalized models. The results showed that the Langmuir model gave the best fit. The process was also found to be endothermic. The maximum phosphate adsorption capacity obtained was 132.02 mg/g (30°C), 156.36 mg/g (40°C) and 184.17 mg/g (50°C), respectively, suggesting that the synthesized zeolite is a promising material and can be used to remove phosphate from wastewater. 相似文献
13.
14.
以油页岩灰渣为实验原料,利用火焰喷枪熔射法制备了空心陶瓷微球.采用TG-DSC对油页岩灰渣进行热分析,采用SEM和XRD分别对油页岩灰渣和空心陶瓷微球的微观形貌和物相组成进行分析.研究结果表明,利用火焰喷枪熔射法制备的微球绝大多数为球状,极少部分为不规则形状,微球破碎后可发现其为空心结构;空心微球的形成机理为:油页岩灰渣粉末受热熔化、发气物质形成气泡、气泡合并、降温凝固、最终形成空心微球;油页岩灰渣自身疏松的结构、所含充足的发气物质和适宜的熔射温度是形成微球空心结构的重要因素. 相似文献
15.
多孔Na-X分子筛比表面积大,离子交换能力强,常被应用于废水处理、气体吸附分离等领域,通常由硅、铝无机盐原料合成得到。粉煤灰、煤矸石、高岭土、油页岩、稻壳灰、甘蔗渣等矿物及废渣含有高含量的硅、铝元素,经过预处理可用于合成Na-X分子筛。本文综述了多种天然矿物和工业固体废料的组成及合成Na-X分子筛的最新研究进展,讨论了不同矿物和固体废料合成Na-X的活化工艺、晶化动力学及机理,重点分析了合成条件对矿物和固体废料合成Na-X的影响,包括硅铝比、晶化温度、晶化时间、阴阳离子、水硅比、碱灰比、超声条件和有机添加剂的影响。 相似文献
16.
17.
18.
19.