2020 Volume 53 Issue 7 Pages 296-303
A combined process that recycles scrap tire rubber and degrades dye wastewater simultaneously using sub/supercritical water was studied. The effect of the reaction temperature and time on the treatment process was investigated. The apparent reaction kinetics was used to analyze the effect of dyes on the recycling of scrap rubber. The experimental results show that both the degree of devulcanization of the scrap rubber and the degradation rate of the wastewater are proportional to the reaction temperature and time. When the reaction temperature is 360°C and the reaction time is 3 h, the sol fraction in devulcanized rubber exceeds 30%, and the chemical oxygen demand (COD) removal rates of both dye wastewaters exceed 90%. Regardless, when the reaction temperature reaches 380°C, the rubber suffers from excessive devulcanization, which in turn increases the COD of wastewaters. Therefore, the key to create a successful combined process is regulating the reaction temperature. The results of apparent reaction kinetics analysis show that the dye wastewater can inhibit the devulcanization process, and the inhibition of disperse dye wastewater is stronger than that of acid dye wastewater, resulting in a lower reaction rate of devulcanization.
