• Energy Research
• 2016-2025close
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By means of the saturation shake-flask technique, the saturation solubility data of 3,3′-diaminodiphenyl sulfone in 14 monosolvents (n-propanol, N,N-dimethylformamide, methanol, ethanol, ethylene g...

Abstract Ammonia oxidation experiments were conducted at high pressure (30 bar and 100 bar) under oxidizing and stoichiometric conditions, respectively, and temperatures ranging from 450 to 925 K. The oxidation of ammonia was slow under stoichiometric conditions in the temperature range investigated. Under oxidizing conditions the onset temperature for reaction was 850–875 K at 30 bar, while at 100 bar it was about 800 K, with complete consumption of NH3 at 875 K. The products of reaction were N2 and N2O, while NO and NO2 concentrations were below the detection limit even under oxidizing conditions. The data were interpreted in terms of a detailed chemical kinetic model. The rate constant for the reaction of the important intermediate H2NO with O2 was determined from ab initio calculations to be 2.3 × 102 T2.994 exp(−9510 K/T) cm3 mol−1 s−1. The agreement between experimental results and model work was satisfactory. The main oxidation path for NH3 at high pressure under oxidizing conditions is NH3 ⟶ + OH NH2 ⟶ + HO 2 , NO 2 H2NO ⟶ + O 2 HNO ⟶ + O 2 NO ⟶ + NH 2 N2. The modeling predictions are most sensitive to the reactions NH2 + NO = NNH + OH and NH2 + HO2 = H2NO + OH, which promote the ammonia consumption by forming OH radicals, and to NH2 + NO = N2 + H2O and NH2 + NO2 = N2O + H2O, which are the main chain-terminating steps.

Abstract As a type of solid waste, the used cigarette filters (UCF) were utilized to produce ester-rich bio-oil via a cleaner production process, namely, microwave-assisted pyrolysis (MAP). The pyrolysis efficiency was significantly enhanced owing to the high heating rate under MAP conditions with assistance of microwave absorber silicon carbide (SiC) in reactor and adding methanol into N2 carrier gas. Compared with the traditional tubular muffle furnace heating method yielding 0% of bio-oil, the MAP heating method obtained 29.17% of bio-oil from UCF. The bio-oil yield from UCF increased from 29.17% to 46.71% due to the introduction of methanol. Results of the gas chromatography/mass spectrometry showed that esters were the main components in the bio-oils (over 40%), especially of methyl acetate (over 12%). The aromatic compounds of phenols and polycyclic aromatic hydrocarbons (PAHs) were also produced from the MAP of UCF. The bio-char from MAP of UCF exhibited the mesoporous property (e.g., over 500 m2/g of specific surface area). It is expected to produce over 350000 metric tons ester-rich bio-oil if the proposed technology can be scaled up globally. It will be a preeminent contribution for the conversion of UCF to the cleaner production and our environments.

Graphene has been used as an electrically tunable material for switchable devices. A large area fabrication of Al-doped ZnO/Al2O3/graphene/Al2O3/gold/silicon device was enabled by a spin-processible hydrophilic mono-layer graphene oxide. The graphene was obtained directly from graphene oxide during the atomic layer deposition without other extra steps. A significant shift of Raman frequency up to 360 cm−1 was observed from graphene in the fabricated device, indicating a structural change in graphene. The absorption from the device was tunable with a negative voltage applied on the Al-doped ZnO side. The generated absorption change was sustainable when the voltage was off and erasable when a positive voltage was applied. The sustainability of tuned optical property in the graphene under investigation can lead to a design of device with less power consumption and many other applications.

Phosphonic acid functionalization of gellan gum and chitosan biopolymers was successfully performed. In the first step, the sorption was investigated using La(III) ions before testing for the recovery of rare earth elements (REEs) from pretreated industrial acidic leachate. The sorbent was characterized by Fourier-transform infrared (FTIR), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), and pH of zero charge (pHPZC) determination. FTIR and EDX results show efficient grafting of phosphoryl groups. The sorption was determined for the crude materials before functionalization (PGEG) and after phosphorylation (TBP-PGEG). More efficient sorption was seen for phosphorylated sorbent than for the crude composite. The sorption capacity is 0.226 mmol La g−1 for the PGEG while the value is 0.78 mmol La g−1 for the TBP-PGEG. We infer that phosphonate groups participate in the sorption. The most effective sorption is at pH = 4. The kinetic behavior was described using pseudo first-order equations (PFORE), pseudo second-order equations (PSORE), and resistance to intraparticle diffusion (RIDE). The sorption isotherms can be better represented by Langmuir and Sips equations than by the Freundlich equation. The sorbent shows high stability performance during reuse cycles with a limit on the decrease in the sorption performances and stability in the desorption performances. We have thus developed a good tool for the recovery of REEs with a selectivity higher than that of the non-functionalized components.

A series of supertetrahedron (ST)-based sodalite (sod)-topology zeolitic MOFs specimens ST-sod-MOFs featuring ultramicroporous square windows and a mesoporous sodcage have been synthesized via a window-space-directed assembly approach.