Papers by Keyword: Zeolite

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Authors: Aurelia Cristina Nechifor, Alexandrina Ivan, Stefan Ioan Voicu, Valeriu Danciulescu, Roxana Trusca
Abstract: In order to improve the capabilities of zeolites for biomedical applications, new composite materials based on polyaniline in-situ generated inside zeolite pores were developed. As precursors for polyaniline several monomers (like aniline and p-phnylenediamine) were used and different oxidant systems (like ammonium peroxodisulphate/HCl, sodium vanadate/ethylic alcohol) were studied and were used for the separation of different biological interest ions and release of antibiotics.
Authors: Shi Ling Guo, Zi Yang Yu, Yi Liang Chen, Xin Xing Chen
Abstract: Zeolite NaKL was in-situ crystallized under static condition with kaolin microspheres calcined at 980 °C as silicon and aluminium sources. Influences of hydrothermal synthesis conditions such as the mole ratio of n(K2O)/n(Na2O), n(OH-)/n(SiO2) and crystallizaion time on crystallization of zeolite L were studied in detail. The crystal phase and morphology of the as-prepared zeolite samples were characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The results showed that the as-synthesized samples owned characteristic peaks of zeolite L with high crystallinity and were covered uniformly by regular crystal of zeolite L on its kaolin microsphere surface , which maintained complete ball shape as before. The optimum conditions to get zeolite NaKL with high crystallinity by this method were found to be the mole ratio of n(K2O)/n(Na2O) =7:3 and n(OH-)/n(SiO2) =0.50 in the reaction mixture, an aging of the reactants at room temperature for 30 h and crystallization temperature 120 °C for 24 h.
Authors: Shi Chun Mu, M. Pan, Run Zhang Yuan
Abstract: Some minerals were considered to store hydrogen on the basis of their porous crystal structure. Besides of crystal graphite and zeolite, some natural clay minerals such as palygorskite-sepiolite minerals with nano-scale channels and polar surface can also store hydrogen. The hydrogen storage mechanism of porous minerals was discussed. The experimental results showed a potential application of palygorskite-sepiolite minerals as the media of hydrogen storage.
Authors: Dao Ji Wu, Yan Jie Wang, Xue Dong Zhai, Xiao Xiang Cheng
Abstract: According to the characteristic of high ammonia nitrogen concentration of Huaihe River in winter, a pilot-scale test was studied in this paper. This paper compared the start-up and operation performance of zeolite biofilter, quartz sand + activated carbon biofilter and zeolite + activated carbon composite biofilter in lower temperature. The results show that three kinds of biofilters for NH4+-N have high remove effects. Average removal rate of zeolite biofilter, quartz sand + activated carbon biofilter, zeolite + activated carbon composite biofilter for NH4+-N were 73%,64% and 78% and effluent NH4+-N concentration were 0.31mg/L,0.24mg/L,0.21mg/L. Average CODMn removal rate of three kinds of biofilters were 5%,13% and 28%. Zeolite + activated carbon composite biofilter does not exist to NO2-N accumulation phenomenon and showed good ability to start-up and running.
Authors: Zhen Peng, Li Zhang, Chun Sheng Wang, Ke Fu Yao
Abstract: It is well-known that TiO2 is an environmental benign photocatalyst which can be used to decompose harmful organic compounds. Recently, many studies are concentrated on the purification of industrial wastewater due to the requirement of environmental protection. In present study, TiO2 nanomaterials supported by fine zeolite particles have been used as the photocatalyst to purify the oily wastewater. It has been found that the oil concentration in the modulated water can be reduced significantly and rapidly under the action of photocatalytic degradation and the ultraviolet light radiation. After 80 minutes, oil concentration in the modulated water can be reduced by more than 80%. The results suggest that TiO2 nanomaterials supported by fine zeolite particles are effective material for purification of oily wastewater. In addition, the present results show that the efficiency of water purification can be significantly increased by use of mechanical stirring during the photocatalytic degradation process.
Authors: Hai Lin, Zhi Ying Zhao, Le Yong Jiang, Wei Wei
Abstract: In this study, the zeolites were treated by NaCl and FeCl3 as an active agent, combined with calcination modification. We studied the ammonia nitrogen (NH3-N) and phosphorus (P) removal of the modified zeolites. The results showed that concentration of NaCl and FeCl3 affected NH3-N and P removal of Secondary sewage effluent greatly. The optimal concentrations of NaCl and FeCl3 were 2.0% and 0.4%. At this condition, the NH3-N and P removal rate of zeolites reached the peak. Application experiments revealed that NH3-N removal rate reached 80.9%, P removal rate reached 83.4%, and COD removal rate reached 96.0%, when the dosage of modified zeolites was 3.0g/L and adsorption duration was 2h for Secondary sewage effluent with 6.0mg/L NH3-N concentration and 1.5mg/L P concentration. After the treatment, the NH3-N and P concentration met Reclaimed Water Quality Standards. The adsorption capability of modified zeolites was better when the pH ranged from 3 to 6. The reason of using NaCl+FeCl3 was that Na+ could exchange the NH3-N in the effluent; Fe3+was able to combine with PO43- in the sewage and formed precipitate; and Fe3+ could also oxidize the organic pollutants.
Authors: Ping Qin, Guan Wen Cheng, Zhi Chao Wu, Xiang Feng Huang, Fei Juan Zhang
Abstract: The result showed that, after addition of a suitable content zeolite to A/O tank, the zeolite sludge had a low resistance and a high membrane flux. The heavy metals in municipal wastewater were inactivated and types of organic matter were adsorbed by the sludge containing zeolite, while sludge compressibility was decreased. It also changed the chemical composition of the sludge and added the inorganic substances such as silicon, aluminum, potassium and sodium, which obviously influenced the way the sludge could be reused.
Authors: Xiao Hua Yu, Hai Liang Lü, Guo Wei Zhou, Li Guo Zhou, Yong Chun Zhang
Abstract: In the present study, three kinds of zeolite (NaP1, NaA, and NaX) were synthesized by a hydrothermal method. These zeolites were modified by cetyl trimethyl-ammonium bromide (CTAB), and used to adsorb methyl orange (MO). NaP1 had the highest adsorption capacity, with a 99.7% MO removal percentage. An orthogonal experiment was conducted to determine the influence of adsorbent dosage, solution pH, initial MO concentration, contact time, and solution temperature on NaP1. The results showed that the initial MO concentration had the most significant effect. The adsorption isotherms of the zeolites are in a good agreement with the Langmuir formula, and the adsorption mechanism is also discussed.
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