Moxin Yu

Removal of organic sulfur compounds from diesel by adsorption on carbon materials

Abstract Removal of organic sulfur compounds from diesel by adsorption on different carbon materials, including activated carbons (ACs), carbon aerogels, carbon nanotubes, and AC cloths, was reviewed. The effect of the textural and surface chemistry property of carbon on desulfurization performance, carbon surface modification, adsorption mechanism, and adsorbent regeneration and the effect of other components, including aromatics, additives, nitrogen compounds, and moisture, on adsorptive desulfurization of diesel fuel were also discussed in detail. Carbon materials showed very high selectivity for removing the dibenzothiophenes, especially for 4,6-dimethyldibenzothiophene, which is very difficult with hydrodesulfurization and other adsorbents. Both the textural and chemical properties of AC have an important impact on the adsorption of DBTs. Adsorption selectivity and capacity can be enhanced further by carbon surface modification. Considering the effect of diffusion hindrance and regeneration, mesoporous carbon is more suitable than microporous carbon with pore size <2 nm. It is necessary to eliminate the inhibiting effect of fuel additive and nitrogen compounds on the DBTs before carbon materials are used for desulfurization of real diesel fuel. In the end, some useful suggestions are also made.

Efficient preparation of porous carbons from coal tar pitch for high performance supercapacitors

摇 Porous carbons (PCs) for supercapacitors were prepared from coal tar pitch by a one鄄step microwave鄄assisted KOH ac鄄 tivation with low KOH consumption. The surface area of the PC (PC2鄄M) made at a KOH / pitch mass ratio of 2 with microwave heating for 30 min reaches 1 786 m / g. The electrochemical performance of the PC electrode for supercapacitors was evaluated in different electrolytes including KOH, K2SO4, Na2SO4, Li2SO4 in water, and tetraethylammoniatetra fluoroborate in propylene car鄄 bonate. The supercapacitors have a high specific capacitance of 267 F / g in 6 mol / L KOH aqueous electrolyte at 0. 1 A / g and a high energy density of 12. 0 Wh / kg at 1 318 W/ kg in a 0. 5 mol / L K2SO4 neutral electrolyte. The one鄄step microwave鄄assisted KOH ac鄄 tivation is a simple, efficient and low energy鄄consumption approach for the preparation of high performance PCs for supercapacitors.

Surface modification of biomass-derived hard carbon by grafting porous carbon nanosheets for high-performance supercapacitors

The conversion of renewable biomass offers a great opportunity for economic fabrication of carbon materials for energy storage devices. However, it is difficult to finely tune the structures of biomass-derived hard carbons (BHCs) due to the inherent robust microstructures of biomass itself, limiting the wide applications of BHCs. Obtaining routes to further optimize the structures of BHCs for supercapacitors is still a large challenge. Inspired by nature in which leaves effectively increase the air-accessible surface area of plants to absorb more carbon dioxide for photosynthesis, we aim to increase the accessible surface area of BHCs for ion adsorption by grafting leaf-like units onto the surface of BHCs. In this study, porous carbon nanosheets (PCNSs) functioning as porous leaves are grafted onto rice husk-derived carbons (RHCs) to fabricate PCNS/RHC composites. The as-prepared PCNS/RHC composites are endowed with sheet-like architecture and abundant short pores. As the electrodes for supercapacitors, the PCNS/RHC composite exhibits a high specific capacitance of 315 F g−1 at 0.1 A g−1 and an excellent rate capability of 189 F g−1 at 50 A g−1. The present study demonstrates an effective and universal strategy to boost the functionality of BHCs materials for energy storage devices.

Synthesis and Zn(II) modification of hierarchical porous carbon materials from petroleum pitch for effective adsorption of organic dyes

The discovery of efficient carbonaceous adsorbents for the removal of organic dyes is a meaningful subject. In this study, hierarchical porous carbon materials (HPCMs) were synthesized from petroleum pitch through template strategy coupled with in-situ chemical activation, and the optimal HPCM was further modified by Zn(II) to get modified HPCM (MHPCM). Their properties and structures were characterized, and their adsorption performances for two typical dyes, methylene blue (MB) and direct black 38 (DB 38), were examined. The as-prepared HPCMs and MHPCM exhibit high specific surface area with hierarchical pore structure, abundant oxygen-containing group, and distinct layered structure. As an adsorbent for dye removals, the MHPCM shows excellent performance with its Langmuir saturated adsorption capacity being 1585.7 and 438.6 mg/g for MB and DB 38, respectively. This is mainly due to the large surface area and hierarchical pore structure of HPCMs, as well as the modification effect of Zn(II). This work provides an efficient strategy for the synthesis of carbonaceous adsorbents used in the adsorptive removal of different molecular size dyes, as well as a new approach for the valuable use of low-cost petroleum pitch.