Regulation of Active Oxygen Species in Cu-MnO_<i>x</i> through MOF Templates for Soot Removal

Herein, a series of bimetallic metal–organic framework derivatives with different Mn/Cu molar ratios were prepared by defect engineering for soot oxidation. The catalysts were analyzed through a combination of characterization and density functional theory (DFT) calculations. The results demonstrate that the removal of organic ligands in the metal–organic frameworks and Cu doping lead to lattice defects on the surface of the catalysts, which are beneficial to the increase of the amount of active oxygen in Cu-MnOx. The catalyst with a Mn/Cu molar ratio of 2:1 (2Mn1Cu) has the highest content of active oxygen (36.33%) and Brunauer–Emmett–Teller (BET) surface area (214.45 m2/g) and then exhibits outstanding catalytic performance with the lowest T90 (412 °C) and apparent activation energy (98.87 kJ/mol) under the tight conditions. The simulation results show that the surface energy and formation energy of oxygen vacancies are low, and the adsorption capacity of reactants is increased, which provides supplementary support for the utilization of active oxygen species

Upgrading of Bio-Oil Using Supercritical 1‑Butanol over a Ru/C Heterogeneous Catalyst: Role of the Solvent

Bio-oil was upgraded using supercritical 1-butanol over a Ru/C heterogeneous catalyst. The results clearly demonstrated that the use of a supercritical solvent resulted in an upgraded product with improved properties compared to upgraded bio-oil using no solvent or subcritical solvent conditions. These improvements included a decrease in oxygen content from 24.9 or 21.4 to 14.5% and an increase in the high heating value (HHV) from 27.9 or 30.5 to 32.0 MJ kg^–1. The most important improvement is that carbon deposition was limited to only 0.2% through the use of a supercritical solvent compared to 9.9% without a solvent. Thus, coking was overcome effectively during the upgrading process. The solvent played several roles: in addition to being the reaction medium and reactant, the solvent facilitated hydrogen dissolution, protected the catalyst, and enhanced the product properties. The reaction pathways in supercritical bio-oil upgrading primarily include esterification, etherification, acetalization, hydrogenation, and hydrodeoxygenation. In this study, the properties of upgraded bio-oil purified via vacuum distillation to remove the solvent were quantified

Simultaneous Removal of Toluene in Gas and Electricity Production by Using a Single-Chamber Microbial Fuel Cell-Biotricking Filter System

Biotrickling filters (BTFs) combined with microbial fuel cell (MFC) provide a sustainable approach to remove volatile organic compounds accompanied by electricity production. In this study, an integrate system (SMFC-BTF) combining single-chamber MFC with BTF is constructed and used to remove toluene-containing gas. A stable removal efficiency of ∼80% is obtained for the 800 ppm toluene accompanied with the current output of 0.25 mA, indicating the feasibility of SMFC-BTF for the simultaneous removal of toluene and electricity production. Moreover, the removal efficiency increases to 95% when the inlet toluene concentration is below 400 ppm under the empty bed retention time of 180s. The detection of intermediate products reveals that cresol, benzyl alcohol, hydroxybenzoic acid, and dihydroxybenzoic acid are produced during the oxidation of toluene by aerobic and anaerobic microorganisms. Accordingly, the pathways of toluene degradation in SMFC-BTF are proposed. The significant difference of microbial species growing in different parts of SMFC-BTF suggests that the process of toluene removal in the system is spatial difference. Our results provide a promising system for the simultaneous removal of toluene and energy recovery