Comparison of 4-chloro-2-nitrophenol adsorption on single-walled and multi-walled carbon nanotubes

<p>Abstract</p> <p>The adsorption characteristics of 4-chloro-2-nitrophenol (4C2NP) onto single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) from aqueous solution were investigated with respect to the changes in the contact time, pH of solution, carbon nanotubes dosage and initial 4C2NP concentration. Experimental results showed that the adsorption efficiency of 4C2NP by carbon nanotubes (both of SWCNTs and MWCNTs) increased with increasing the initial 4C2NP concentration. The maximum adsorption took place in the pH range of 2–6. The linear correlation coefficients of different isotherm models were obtained. Results revealed that the Langmuir isotherm fitted the experimental data better than the others and based on the Langmuir model equation, maximum adsorption capacity of 4C2NP onto SWCNTs and MWCNTs were 1.44 and 4.42 mg/g, respectively. The observed changes in the standard Gibbs free energy, standard enthalpy and standard entropy showed that the adsorption of 4C2NP onto SWCNTs and MWCNTs is spontaneous and exothermic in the temperature range of 298–328 K.</p

Hydrogen production from biogas reforming: an overview of steam reforming, dry reforming, dual reforming, and tri-reforming of methane

International audienceGreen hydrogen can be produced from biogas as a renewable resource using a multistep process, including mainly biogas reforming, water-gas-shift reaction, and hydrogen separation. This chapter is focused on different methane reforming processes: steam reforming, dry reforming, dual reforming, and tri-reforming. In fact, only steam methane reforming (SMR) has been commercialized, but it is well known as a highly energy intensive process. Thus, alternative processes, such as dry, dual, and tri-reforming, are being developed. These solutions are significantly interesting for biogas reforming because of its high carbon dioxide content, which can be used as an oxidant. For each process, different aspects will be presented, including: thermodynamic equilibrium, process at industrial scale or research laboratory development, kinetic models, and mechanistic study