Papers by Keyword: Scrap Tire

Abstract: Activated carbons were prepared by chemical activation from scrap tire with two chemical reagents, NaOH and KOH. The activation consisted of different impregnation of a reagent followed by carbonization in nitrogen at 700°C. The resultant activated carbons were characterized in terms of BET surface area, methylene blue adsorption and iodine number. The influence of each parameter of the synthesis on the properties of the activated carbons was discussed, and the action of each hydroxide was methodically compared. It is the first time that preparation parameters and pore texture characteristics are simultaneously considered for two closely related activating agents of the same char precursor. Whatever the preparation conditions, it was shown that KOH led to the most microporous materials, having surface areas and adsorption properties (methylene blue adsorption and iodine number) higher than those obtained with NaOH, which was in agreement with some early works. However, the surface areas, methylene blue adsorption and iodine number obtained in the present study were much higher than in previous studies, up to 951 m2/g, 510 mg/g and 752 mg/g, respectively, using scrap tire waste char:KOH equal to 1:1. The thorough study of the way each preparation parameter influenced the properties of the final materials bought insight into the activation mechanisms. Each time it was possible; the results of scrap tire waste chemically activated with hydroxides were compared with those obtained with anthracites; explanations of similarities and differences were systematically looked for.

Abstract: Two activated carbons employing Scrap Tire as precursor were produced by using two different activating agents, HCl and H₂SO₄ (fixed impregnation ratio 1:1). Both of activated carbons were allowed by single-step to get difference carbonized at 500, 600 and 700°C in a muffle furnace for 1 h. Activated carbons differed with the physical structure, chemical and adsorption properties which were derived from Scanning Electron Microscope, and N₂ adsorption/desorption isotherms. Batched sorption studies were performed to compare the iodine and methylene blue adsorption properties of two carbons. The carbon materials obtained from sulfuric acid activation of 500°C has BET surface area as high as 1066.70 m²/g, Methylene blue adsorption and Iodine number of 288.90 and 590.50 mg/g, respectively. The surface area and adsorption properties of carbon produced using sulfuric acid activation were higher than that produced using hydrochloric acid activation. The results suggest the feasibility of the process from the point of view of both porous texture and adsorption yield.

Abstract: Scrap tire is considered an environmental concern with inadequate final disposal. A good alternative can be to use the tire as an energy source. Pyrolysis is a thermal process that can transform the rubber portion of used tires into oil, gas and pyrolytic carbon. This type of carbon can be converted into carbon black (CB). The lime industry that demands great amount of energy could be one of the ways to take advantage the scrap tires adequately as energy source. This work aimed to study the operational conditions of the pyrolysis process as well as investigating the possibility to use the pyrolysis products from used tires as industrial fuel. A batch pilot-scale pyrolysis unit was built. Temperatures from 400 to 600oC and relative pressures from 0 to -500 mmHg were investigated in order to evaluate product distribution and quality. Experimental results showed that as the reactor temperature was increased the pyrolytic carbon yield remained constant with a mean of 39.8 wt % and the pyrolytic oil yield reached a maximum value of 45.1 wt % at 500 °C. It is also possible to show that the pyrolytic oil can be used as liquid fuels because of its high heating value (40-42 MJ/kg), excellent viscosity (1.6-3.7 cS), and reasonable sulfur content (0.97-1.54wt %). In addition, chemical and physical characterization was made in order to compare the pyrolytic carbon and oil with currently fuels used in Brazilian lime industries (wood charcoal and coke of petroleum).

Abstract: Unsaturated polyester resins are extensively used in the automotive industry as matrix for polymer based composite materials, but have poor impact resistance. Toughness can be improved dispersing a softer phase in brittle polymers. Scrap tyres constitute a significant waste problem and are a low-cost source for rubber. The objective of this work is the mechanical characterization of matrix systems containing solid rubber particles obtained from scrap tyres. Several pre-treatments were tested based on contact time and temperature. The flexural and Charpy impact behaviour of the modified resins showed a decrease in performance. Dynamic mechanical tests did not result in clear evidence of phase mixing. Optical microscopy showed the presence of contaminant particles, which were considered the cause for the low performance. Among the modified resins, a positive shift in flexural behaviour occurred when pre-heating was used. It is thought the strategy may prove effective in enhancing resin toughness, if the waste rubber is purified prior to its utilization.