Search

Titanium-based SnO2 with Sb dopant (Ti/Sb-SnO2) was of interest in the field of electro-catalytic oxidation due to its high organic oxidation rates. However, the relatively poor mass transfer performance and short service time limited its practical application. To overcome this problem, Ti/Sb-SnO2 electrode was fabricated on mesh substrate and used as the anode for electrochemical oxidization of phenol. Compared to the anode prepared on planar Ti, the mesh anode with compact and uniform catalyst surface lowered electron transfer resistance and higher Oads content (17.41%), which benefited the generation of hydroxyl radicals (·OH) (increment of 24.5%). In addition, this structure accelerated the fluid perturbation around electrode in microscopic scale as the COMSOL simulation result indicated; the electric potential on mesh anode varied regularly along the undulant terrain of electrode so that the mass transfer coefficient was enhanced by 1.67 times. These structure-dependent characteristics contributed to the superior electro-catalytic performance toward degradation of phenol. Experimental results showed that mesh anode had a higher TOC removal efficiency of 90.6% and mineralization current efficiency of 20.1% at current density of 10 mA cm−2, which was 9.95% and 21.6% higher than the planar anode, and the service lifetime was 1.89 times longer than planar anode. This highly electro-catalytically active and stable Ti/Sb-SnO2 mesh electrode showed a potential application prospect toward electro-catalytic degradation process. [ABSTRACT FROM AUTHOR]

A simple, cost-effective and efficient approach is highly in demand for high yield preparation of hierarchical porous carbons. Here, we report a new method of in situ generated MgO or CaCO 3 template coupled with KOH activation to prepare various porous carbons with high carbon yield (20%–50%) via directly pyrolyzing the mixture of polymers, template precursors, coal tar pitch and KOH. The influence of polymers, template precursors and KOH on the morphology, surface area, pore structure and supercapacitor performance have been studied and discussed in detail. These as-prepared porous carbons possess high surface area (805–1525 m 2 g −1 ), hierarchical pores composed of micropores, small mesopores and macropores, and high oxygen doping (10.16–13.51 wt%), which endow C x-y-a with superior capacitive performance. The C PVA-Mg(AC)2-a , C RF-Mg(AC)2-a , C MF-MgCl2-a and C MF-Ca(AC)2-a electrodes exhibit high specific capacitance of 350, 321, 329 and 311 F g −1 at 1 A g −1 and satisfying rate performance of 298, 276, 285 and 269 F g −1 corresponding to 85.1%, 86%, 86.6% and 86.5% retention at 20 A g −1 . The C PVA-Mg(AC)2-a electrode shows specific capacitance as high as 251 F g −1 at 1 A g −1 and excellent rate capability of 90% retention at the large current density of 10 A g −1 in two electrode system. The C PVA-Mg(AC)2-a symmetrical supercapacitor presents a high energy density of 22.3 Wh kg −1 at 876 W kg −1 in 1 M Na 2 SO 4 electrolyte. The present work highlights the in situ templating coupled with KOH activation strategy as a facile protocol for high yield production of porous carbon materials with excellent performance for supercapacitors. [ABSTRACT FROM AUTHOR]

Magnetic particles (MPs) assisted powdered activated carbon (PAC) is a promising composite material for adsorption removal of micropollutants. The fractional amount of Fe 3 O 4 impacts the balance between adsorption capacity and magnetic property of magnetic activated carbons (MPACs), and therefore it affects the extent of sulfamethoxazole (SMX) removal. Here, five MPACs with different mass ratios of Fe 3 O 4 : PAC (1:1, 1:2, 1:4, 1:6, and 1:8) were prepared using a hydrothermal method and characterized by various spectroscopic methods. The spherical shaped MPs were monolayerly deposited on PAC with fewer pores blocked when the mass ratio of Fe 3 O 4 was comparatively low (≤ 20%). MPAC6 (14.3 wt% of Fe 3 O 4 ) had the best overall performance, with good Langmuir adsorption capacities for SMX (173.0 mg g -1 ) and excellent magnetic properties (9.0 emu g -1 ). Corresponding adsorption kinetics fitted well with the pseudo second-order kinetic model. The negative ΔG 0 (-25.6 to -27.2 KJ mol -1 ) and ΔH 0 (-9.14 KJ mol -1 ), and positive ΔS 0 (0.55 KJ mol -1  K -1 ) properties indicated the spontaneous and exothermic nature of the adsorption process accompanied by an increase in entropy. The strong cation-assisted electron donor-acceptor and hydrophobic interactions were contributed to a high extent of SMX removal in the pH range of 2-4. Formation of negative charge-assisted H-bonds was responsible for the adsorption of hydrophilic SMX - on negatively charged MPAC6 in alkaline solution. Desorption and regeneration experiments showed SMX removal was still 92.3% in the 5th cycle. These findings give valuable insights into the interactions between SMX and MPACs and guide for choosing sustainable magnetic adsorbents for environmental applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)