Study On Charateristics And Adsorption Performance Of Non-activated Tire-based Pyrolytic Char

With the rapid development of the transportation industry, the waste tire productionhas skyrocketed. Contamination of the environment from vast number of scrap tires hasbecome an increasingly serious problem. Traditionaly, it seems to be no effective way torecycle or disposal of these massive waste tires. However, pyrolysis offers an alternative towaste tires disposal and can result in the recovery of useful products in an environmentallyfriendly manner. Pyrolysis is a new technology for scrap tires reduction, harmlessness andreuse.Owing to its high carbon content, NATPC (non-activated tire-based pyrolytic char),the solid by-product from waste tire pyrolysis without subsequent activation procedure,was proposed as an alternative adsorent to instead of the expensive activated carbon in thispaper. On the basis of the current research results, the influence of pyrolysis condition onNATPC adsorption capacity, kinetic mechanism, suitable adsorbates and their bestadsorption condition for NATPC were discussed in this paper.Waste tires were pyrolysed in a home-made tubular pyrolysis furnace under nitrogengas circumstance. The influence of pyrolysis temperature, heating rate, heating time andground tires size were analyzed to determine the best pyrolysis condition for NATPCpreparasion. Results show that the effect of temperature on the adsorption capacity ofNATPC is the greatest, heating time is greater, and heating rate is the least. With theincreasement of pyrolysis temperature, the volatile products increase. The pyrolysisprocess end until the temperature up to550℃, which indicates that the pyrolysis conditionshould be higher than550℃, To ensure a good adsorption, pyrolysis at600－800℃for1.5-2hours is suggested for NATPC preparasion.Element analyzer, Scanning Electron Micrograph (SEM), Fourier Transform infraredspectroscopy (FTIR) and nitrogen adsorption isotherms were used to discuss the elementcomposition, surface topography, chemical functional groups and pore characteristics. Thecarbon content of NATPC exceeded70%. The surface texture of NATPC was rough andfull of a large number of irrguler pore space. Respectively, the Brumauer-Emmett-Teller(BET) specific surface area and average pore size of NATPC was about89m2g-1and29.06nm, which demonstated the mesoporous structure. There were many polyaromaticring and ester groups in NATPC.Using thermogravimetric analysis, kinetic model of waste tire pyrolysis process was studied on the basis of different pyrolysis temperature phase. Based on heating rate, threeor four phase was existed in waste tire pyrolysis process. There were four reaction phasewhen heating rate is lower than10℃/min, otherwise, three reaction phase when heatingrate is between10-40℃/min. Activity energy (refered as E) and pre-exponential factor(refered as A) of pyrolysis reaction in different phase were simulated, which indicate that Eand A were highest in the last reation phase with correlation coefficient varying from0.86to0.99.Methylene Blue, humic acid, phenol and Cu2+were chosen as adsorbates to determinethe adsorption capacity of NATPC. The adsorption performance onto NATPC obtained at800℃for1.5hours was conducted under different contact time, adsorbent dosage,adsorbate initial concentration, pH and temperature. Results show that NATPC can adsorbCu2+, Methylene Blue and humic acid well, which indicated NATPC can be used as anexcellent adsorbent with good efficiency, simple manufacture and low cost. Theappropriate adsorbates for NATPC adsorption were heavy metal and macromolecules.