N-hydroxyphthalimide anchored on hexagonal boron nitride as a metal-free heterogeneous catalyst for deep oxidative desulfurization

A metal-free N-hydroxyphthalimide/hexagonal boron nitride(NHPI/h-BN)catalytic system was developed for deep oxidative desulfurization(ODS)of fuel oils.Detailed experiments find that the heterogenization process of loading NHPI on h-BN not only benefits to the dispersion and utilization of NHPI,but also can significantly promote the catalytic performance.By employing NHPI/h-BN as the catalyst,azodiisobutyronitrile(AIBN)as the metal-free initiator,a 95%conversion of dibenzothiophene(DBT)can be acquired under the reaction conditions of 120°C and atmospheric pressure with molecular oxygen(O_(2))as oxidant.Moreover,the heterogenization is convenient for the regeneration of the catalyst with>94%DBT conversion after being recycled seven times.Characterizations illustrate that the promoted catalytic activity along with the regenerability originate from the interactions between NHPI and h-BN.The catalytic mechanism study shows that molecular oxygen is readily activated by the NHPI/h-BN to form a superoxide radical(O_(2)^(·-)),which oxidize DBT to DBTO2 for desulfurization.

Catalytic oxidation of pentanethiol on basic nitrogen doped carbon hollow spheres derived from waste tires

A series of basic nitrogen doped carbon hollow spheres(p-N-C) catalysts derived from waste tires were prepared by a green, facile and environmental “leavening” strategy for the catalytic oxidation of pentanethiol. Compared to pristine carbon, the p-N-C has a higher surface curvature conducive to the enrichment of substrates, leading to an excellent catalytic performance. This increased surface curvature of p-N-C was fabricated on the synergistic effect of two foaming agents((NH4)2 C2 O4 and NaHCO3), and the released gas also endows the spherical shell of p-N-C with a hierarchical porous structure, promoting the accessibility of active sites with pentanethiol. Pyridine-like and pyrrolic-like nitrogen atoms were investigated as reactive sites on the p-N-C to accelerate the electron transfer from sulfur to active surface oxygen and enhance the adsorption/oxidation process. As a result, the optimal p-N-C catalyst exhibits superior adsorption and oxidation performance(99.9%) of pentanethiol, outperforming the “unleavened”catalyst(20.8%). This work offers a new avenue for the fabrication of highly efficient materials for the desulfurization of fuel.

Enhanced adsorption performance for antibiotics by alcohol-solvent mediated boron nitride nanosheets

The development of high-efficient adsorbents for the treatment of antibiotics from contaminated water has been of great concern.This work introduced an alcohol-solvent mediated strategy to increase the specific surface area(SSA)and porosity of hexagonal boron nitride nanosheets(BNNSs)for improving tetracycline(TC)removal efficiency.The BNNSs synthesized with the mediation of n-propanol solvent(BN-P)exhibited the largest pore volume and relatively high SSA(increased by 34%and 64%,respectively,compared with that synthesized under the mediation of water)in its structure,which in turn facilitated the mass transfer of TC molecules onto BN-P framework.The remarkable adsorption performance of BN-P,with 20%increase in equilibrium adsorption capacity and Langmuir maximum adsorption capacity of 556 mg·g^(-1),was achieved for capturing TC within just 3 h,which is mainly through p-p interaction and electrostatic force.Pseudo-second kinetics equation can well illustrate the adsorption process,while Freundlich and Langmuir isotherm models fitted the equilibrium data well.Thermodynamics study demonstrated a spontaneous exothermal adsorption process.Furthermore,the strong environmental suitability and notable recycling performance of BN-P revealed its good application prospect in removing antibiotic TC from wastewater.