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Fernandes, Valter J.; Araújo, Antônio S.; Medeiros, Rosemary Álvares de; Matos, J. R.; Mercuri, Lucildes Pita; Silva, A. O.; Melo, D. M. A.

doi:10.1023/a:1010142003725

Cited by 15 publications

(4 citation statements)

References 19 publications

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“…The thermal degradation activation energy ( E a ) values of the composites were determined with the Kissinger and Ozawa methods. 3, 4, 14, 18 According to the Kissinger method, E a is determined from the slope of a log β versus 1/ T d plot, corresponding to − E a / R with eq. (2): where β is the heating rate (°C/min), T d is the peak maximum for degradation temperature, E a is the activation energy, and R is the gas constant.…”

Section: Resultsmentioning

confidence: 99%

“…Different types of zeolite minerals, either natural (e.g., clinoptilolite, mordenite, chabazite) or synthetic (e.g., A type, X type, Y type), have been used as particulate fillers. 2–4 All commercial zeolites owe their value to one of the following properties: ion exchange, adsorption, or catalysis. They have unusual crystalline structures that give them unique chemical properties.…”

Section: Introductionmentioning

confidence: 99%

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Effect of zeolite filler on the thermal degradation kinetics of polypropylene

Pehlivan

Balköse

Ülkü

et al. 2006

J of Applied Polymer Sci

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ABSTRACT:In this study, the thermal degradation behavior of polypropylene (PP) and PP-zeolite composites was investigated. Clinoptilolite, a natural zeolitic tuff, was used as the filler material in composites. The effects of both pure clinoptilolite and silver-ion-exchanged clinoptilolite on the thermal degradation kinetics of the PP composites was studied with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Polymer degradation was evaluated with DSC at heating rates of 5, 10, and 20°C/ min from room temperature to 500°C. The silver concentration (4.36, 27.85, and 183.8 mg of Ag/g of zeolite) was the selected parameter under consideration. From the DSC curves, we observed that the heat of degradation values of the composites containing 2-6% silver-exchanged zeolite (321-390 kJ/kg) were larger than that of the pure PP (258 kJ/kg). From the DSC results, we confirmed that the PPzeolite composites can be used at higher temperatures than the pure PP polymer because of its higher thermal stability. The thermal decomposition activation energies of the composites were calculated with both the Kissinger and Ozawa models. The values predicted from these two equations were in close agreement. From the TGA curves, we found that zeolite addition into the PP matrix slowed the decomposition reaction; however, silver-exchanged zeolite addition into the matrix accelerated the reaction. The higher the silver concentration was, the lower were the thermal decomposition activation energies we obtained. As a result, PP was much more susceptible to thermal decomposition in the presence of silver-exchanged zeolite.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of zeolite filler on the thermal degradation kinetics of polypropylene

Pehlivan

Balköse

Ülkü

et al. 2006

J of Applied Polymer Sci

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“…Some examples are the removal of fluoride using clinoptilolite with a maximum adsorption capacity of 12.3 mg/g [37], the gasoline desulfurization employing 5A and 13X zeolites with a removal of 16.7 mg/g [38], and the nitrite removal from wastewater [39]. The superficial zeolite modification using NH 4 Cl and a subsequent thermal treatment have been utilized to tailor synthetic chabazites for the thermal degradation of high-density polyethylene to low molecular mass hydrocarbons [40] and the adsorption of ethane (41 mg/g) and propane (81 mg/g) [41]. This material had been also employed as a catalyst in the methanol to olefins reaction (forming polyaromatic coke species) [42].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Arsenic, Lead, Cadmium, and Chromium Ions from Aqueous Solution Using a Protonated Chabazite: Preparation, Characterization, and Removal Mechanism

Pinedo-Torres

Bonilla-Petriciolet

García-Arreola

et al. 2023

Adsorption Science & Technology

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The adsorption of As(V), Pb(II), Cd(II), and Cr(III) ions from aqueous solutions on natural and modified chabazite was studied. The functionalization of chabazite was performed via a protonation and calcination with the aim of generating Lewis acid sites to improve its anion exchange properties. The surface and physicochemical properties of both adsorbents were studied and compared. The adsorption isotherms of tested heavy metal ions were quantified and modeled to identify the best isotherm equation. Steric parameters for the adsorption of these ions were also calculated with a monolayer statistical physics model. Natural chabazite showed the maximum adsorption capacity for Pb(II), while the modified zeolite improved its As(V) properties in 79%. These results showed that the modified zeolite was able to remove both cations and anions from aqueous solution. The application of this functionalized chabazite can be extended for the removal of other anionic pollutants from water, thus opening the possibility of preparing new adsorbents with tailored properties for water treatment.

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“…Zeolitic materials are often used in the catalytic degradation of polymers, due to their excellent properties as catalysts, in addition to contributing to the resolution of the environmental problem generated by plastic waste. The zeolites combine high acidity with shape selectivity, high surface area, and high thermal stability [12,13]. These particular properties promote the breaking of the C-C bonds of the polymer chains and determine the products obtained [14,15].…”

Section: Introductionmentioning

confidence: 99%

Thermo-catalytic degradation of PE and UHMWPE over zeolites with different pore systems and textural properties

et al. 2020

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The thermo-catalytic degradation of polyethylene (PE) and ultra-high molecular weight polyethylene (UHMWPE) was studied in the presence of zeolites (ZSM-5, ZSM-22, and ferrierite) with different pore systems and textural properties. The zeolites were physically mixed with polymers in the proportion of 30 wt% and submitted to thermogravimetric analysis at heating rates of 5, 10, 20, and 30 °C.min-1. The activation energy of the degradation process was determined using the Flynn-Wall-Ozawa method. The addition of zeolites to polymers has considerably reduced the temperature of degradation. ZSM-22 demonstrated greater efficiency in the degradation of PE because it has a smaller crystallite size, promoting a shorter diffusional path for the polymer fragments coming from the surface. Ferrierite showed a lower energy level in the degradation of UHMWPE, showing the need for synergy between the accessibility of the structure and acidity of the catalyst to promote the cracking of this polymer.

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Cited by 15 publications

References 19 publications

Effect of zeolite filler on the thermal degradation kinetics of polypropylene

Effect of zeolite filler on the thermal degradation kinetics of polypropylene

Adsorption of Arsenic, Lead, Cadmium, and Chromium Ions from Aqueous Solution Using a Protonated Chabazite: Preparation, Characterization, and Removal Mechanism

Thermo-catalytic degradation of PE and UHMWPE over zeolites with different pore systems and textural properties

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