FORTH Institute of Petroleum Research

Abstract This study presents the preparation and evaluation of a novel adsorbent designed for removing organic solvents from wastewater, focusing on toluene, a common toxic solvent. The adsorbent, a unique blend of silica aerogel, recycled polyethylene terephthalate (rPET) short fibers, FeCl3, and chitosan, was rigorously tested and characterized using a range of methods. The adsorption performance of the adsorbent was tested for various organic solvents, with detailed attention to toluene. The adsorption parameters, including adsorbent dosage, initial toluene concentration (100-1000 ppm), contact time (15-40 minutes), pH (2-10), and temperature (18-40 °C), were investigated using response surface methodology (RSM) based on central composite design (CCD). The maximum toluene removal efficiency was 99.52%, achieved under optimal conditions. The adjusted coefficient of the determination of the model was 0.968, which indicates that the model was entirely appropriate and accurate. Kinetic studies suggested that the adsorption followed pseudo-second-order kinetic, while equilibrium data were well-fitted to Langmuir and Freundlich isotherms. The stability of the adsorbent across four regeneration cycles demonstrates its potential for long-term application in sustainable water treatment. These results, along with the potential for long-term application, suggest that the developed adsorbent is a promising solution for effectively remedying toluene and some organic matters like crude oil-contaminated wastewater, contributing to environmental protection and plastic waste management.

The production of syngas (H2 and CO)—a key building block for the manufacture of liquid energy carriers, ammonia and hydrogen—through the dry (CO2−) reforming of methane (DRM) continues to gain attention in heterogeneous catalysis, renewable energy technologies and sustainable economy. Here we report on the effects of the metal oxide support (γ-Al2O3, alumina-ceria-zirconia (ACZ) and ceria-zirconia (CZ)) on the low-temperature (ca. 500–750 °C) DRM activity, selectivity, resistance against carbon deposition and iridium nanoparticles sintering under oxidative thermal aging. A variety of characterization techniques were implemented to provide insight into the factors that determine iridium intrinsic DRM kinetics and stability, including metal-support interactions and physicochemical properties of materials. All Ir/γ-Al2O3, Ir/ACZ and Ir/CZ catalysts have stable DRM performance with time-on-stream, although supports with high oxygen storage capacity (ACZ and CZ) promoted CO2 conversion, yielding CO-enriched syngas. CZ-based supports endow Ir exceptional anti-sintering characteristics. The amount of carbon deposition was small in all catalysts, however decreasing as Ir/γ-Al2O3 > Ir/ACZ > Ir/CZ. The experimental findings are consistent with a bifunctional reaction mechanism involving participation of oxygen vacancies on the support’s surface in CO2 activation and carbon removal, and overall suggest that CZ-supported Ir nanoparticles are promising catalysts for low-temperature dry reforming of methane (LT-DRM).