There is general agreement that primary pyrolysis products of end-of-life tyres should be valorised to improve the economics of pyrolysis. In this work, tyre pyrolysis char (TPC) is produced in a pyrolysis pilot plant designed and built at our home university. The produced TPC was upgraded to tyre-derived activated carbon (TDAC) by activation with CO2, and then characterised using stereological analysis (SA) and nitrogen adsorption at 77 K. SA showed that the grains of TPC and TDAC were quasi- spherical and slightly elongated with a 25% increase in the mean particle cross-section surface area for TDAC. The textural properties of TDAC demonstrated the BET and micropore surface areas of 259 and 70 m2/g, respectively. Micropore volume and micropore surface area were 5.8 and 6.7 times higher for TDAC than TPC at 2 nm, respectively. The n-hexane adsorption was investigated using experiments and modelling. Eight adsorption isotherms along with three error functions were tested to model the adsorption equilibrium. The optimum sets of isotherm parameters were chosen by comparing sum of the normalized errors. The analysis indicated that the Freundlich isotherm gave the best agreement with the equilibrium experiments. In relation to different activated carbons, the adsorption capacity of TDAC for n-hexane is about 16.2 times higher than that of the worst reference material and 4.3 times lower than that of the best reference material. In addition, stereological analysis showed that activation with CO2 did not change the grain’s shape factors. However, a 25% increase in the mean particle cross-section surface area for TDAC was observed.
This paper aims to show the effect of activation method of tyre pyrolysis char (TPC) on adsorption of bisphenol A (BPA) from aqueous solutions. The TPC was produced from end-of-life-tyres (ELT) feedstock in a pilot plant at 773 K. Activation was accomplished using two classical methods: physical activation withCO2 and chemical activation withKOH. The two produced adsorbents had pores ranging from micro- to macropores. Distinct differences in the BET surface areas and pore volumes between the adsorbents were displayed showing better performance of the chemically activated adsorbent for adsorption of BPA from water.
The results of the kinetic studies showed that the adsorption of BPA followed pseudo-second-order kinetic model. The Freundlich, Langmuir, Langmuir–Freundlich and Redlich–Peterson isotherm equations were used for description of the adsorption data. The Langmuir–Freundlich isotherm model best fits the experimental data for the BPA adsorption on both adsorbents. The Langmuir–Freundlich monolayer adsorption capacity, qmLF, obtained for the CO2-activated tyre pyrolysis char (AP-CO2) and KOH-activated tyre pyrolysis char (AP-KOH) were 0.473 and 0.969 mmol g��1, respectively.