Waste tire particles as efficient materials towards hexavalent chromium removal: Characterisation, adsorption...

The growing demand for vehicles is increasing every year, and this paves the way for the environmental problem for the generation of the waste tire (WT) and associated disposal after their end life. On the other direction, effluent from tannery and electroplating industries contented with a higher concentration of chromium, which is a toxic pollutant, induces mutation effects. In this work, the approach of reutilization of waste tires as adsorbent is reported towards the sequestrations of hexavalent chromium (Cr(VI)) from the simulated system. The waste tire sample is activated using orthophosphoric acid (H₃PO₄) and utilized for adsorption studies. Adsorption studies are performed with native tire sample (NTP) and activated tire sample (ATP). About 96.5% of Cr(VI) adsorption efficiency was attained using ATP and at the optimal adsorption solution pH 2.0. The adsorbent performed relatively well in wide a range of initial solution pH tested in the present research. The experimental data analysis of Cr(VI) adsorption onto NTP and ATP revealed the best fit with the kinetic model of pseudo-second-order. Further, the equilibrium data were analysed using two-parameter isotherms, relatively the Langmuir isotherm best represented in both NTP and ATP. ATP demonstrated with higher Cr(VI) removal performance with an adsorption capacity of 102.90 mg/g, according to the Langmuir model. The proposed idea of utilizing waste tire particles as adsorbents in the treatment of Cr(VI) contaminated water offers valuable guidance towards further investigations in the directions of dynamic adsorption and effluent treatment.