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In textile wastewater, ions such as Cl−, NO3−, SO42− added as salts (dye-enhancers), were reported to exacerbate the deactivation of TiO2 surface in aqueous media. The rate of degradation of a model cationic dye methylene blue (MB) with or without NaCl and nature of adsorbed species on pure anatase TiO2 were investigated, other factors considered were pH4 and pH10, ultraviolet light (UV). XPS analysis of samples T1–T8, shows varying values of percent atomic concentration (PAC) from fresh sample Tf. For Tf, Ti (25.88%) and O (68.07%) values were higher than in any other sample and has the least C (4.11%) with no traceable amount of N, S and Na. For the deactivated samples, in addition to basic elements Ti, O and C, there were traces of new elements, nitrogen (N) in T1 (N: 1.16%), no nitrogen or sulfur (S) in T2, in T3 (N: 3.34%, S: 0.84%), T4 (N: 3.17%, S: 1.72%), T5 (N: 1.46%), T6 (N: 1.16%), T7 (N: 3.21%, S: 0.97%) and T8 (N: 3.02%, S: 1.11%, Na: 3.02%), no Cl− was found in any sample. Shifts were observed in the XPS high resolution spectra (HRS) in C1s, O1s, Ti2p, N1s, S2p and Na1s regions. FTIR confirmed the new adsorbed species on deactivated samples (T1–T8).

Microbial fuel cell is a sustainable and renewable technology which commonly uses graphite as cathode for hydrogen peroxide production. One of the limitations of using graphite cathode is the slow kinetics of oxygen reduction reaction. Nitrogen doping has been demonstrated to be an efficient approach to regulate the electronic as well as surface characteristics of graphite cathode. Therefore, in this study nitrogen doping of graphite cathode was performed to determine the feasibility of H2O2 production and energy generation in a dual chamber MFC. An integrated approach of quantum chemical calculation in combination with experimental investigation was used. Quantum chemical calculations confirmed the production of H2O2 with the lowest Gibb's free energy of −63 kcal/mol. For validation, ammonia treatment of graphite cathode was performed. The XPS analysis of doped cathode revealed the presence of Graphitic-N functionalization with overall N1s content of 2.96%. Cyclic voltammetric analysis of nitrogen doped cathode further confirmed the production of H2O2 at the peak current value of −4.0 mA and on-set potential of −0.55 V. Following CV analysis, hydrogen peroxide production experiments were performed in a dual chamber MFC. Maximum of 175 mg/L of H2O2 was obtained with simultaneous power generation of 47.61 W/m3, indicating the synergetic effect of nitrogen doped cathode. Thus, from the findings of quantum chemical evaluation and experimental investigation, it is concluded that nitrogen doping of graphite cathode is an efficient approach to improve the performance of MFC in terms of H2O2 production and power generation.

Catalytic hydrogenation is considered as an efficient technique for upgrading pyrolysis bio-oil. High flammability of hydrogen gas in contact with air leads to difficult control of high pressurized hydrogen gas in large-scale systems. Meanwhile, molecular hydrogen production is a costly industrial process. Thus, hydrogenation study using hydrogen donor (H-donor) material as alternative for hydrogen gas could be useful in terms of cost and safety control. In this study, the potential of decalin and tetralin for use as hydrogen source was investigated in transfer hydrogenation of renewable lignin-derived phenolic compounds (phenol, o-cresol and guaiacol) and a simulated phenolic bio-oil over Pd/C and Pt/C catalysts. Reaction mechanisms of H-donor dehydrogenation and phenolics hydrogenation were studied. Catalytic activity of Pt/C for transfer hydrogenation of the phenolic compounds was higher than that of Pd/C at reaction temperature of 275 °C. Decalin as hydrogen source showed to be more efficient for hydrogenation of the phenolic compounds compared to tetralin. In addition, the influence of water content on transfer hydrogenation activity was studied by employing the water to donor ratios of 0/100, 25/75, 50/50 and 75/25 g/g. Maximum hydrogenation of phenol as bio-oil model compound was observed at water to donor ratio of 50/50 g/g.

Nanoparticle formation from their respective precursors through bottom-up method is a very fascinating practice in nanotechnology. This research contribution discusses two promising bottom-up methods: (i) controlled precipitation of Ni, Fe, and Co nanoparticles and reinforcement with silicate through modified Stober method and (ii) chemical vapor deposition of nanocarbon from methane. Experimental results reveal that metal oxide particles were formed as single-crystal nanoparticles after silicate addition and exhibited catalytic activity enhancing features, such as low particle size and high surface area and porosity. The single-point surface area increased from 62.22 m2/g to 91.50 m2/g, 35.13 m2/g to 97.31 m2/g, and 14.29 m2/g to 48.96 m2/g for n-NiO, n-FeO, and n-CoO nanoparticles, respectively, after silicate incorporation. Preliminary catalytic activity was also analyzed in a fixed-bed pilot plant. n-NiO/SiO2 nanoparticles were found to be the most efficient catalyst for thermocatalytic methane decomposition and generated 57.28% hydrogen at 730 °C. Physical and chemical characteristics of the fabricated nanocatalysts were determined using N2 adsorption–desorption measurement (Brunauer–Emmett–Teller method), X-ray diffraction (XRD), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H2-TPR), and field-emission scanning electron microscopy (FESEM) analyses. Produced nano-carbon was inspected with TEM, FESEM and XRD.

On the basis of the interplay between the metal function of oxo-anions, and structure of zeolites and its acidic properties, we report an innovative approach for enhancing acidity of sulfated zirconia, SZ. This concerns the superiority of SZ comprised of single-Bronsted acid sites dispersed on ZSM-5 over Ag, Ti and W. The influence of doping ZrO2 on MFI framework of ZSM-5 was studied against other composite catalysts characterized by temperature-programmed desorption of ammonia (NH3-TPD), IR spectra of pyridine adsorption, N2 sorption, powder X-ray diffraction, elemental analysis via FE-SEM and EDX. Results showed uniform pore size, high mesopore volume, high surface area, and acid densities on the catalysts. Despite lower pore size distribution, Zr/ZSM-5 exhibited highest total acidity (0.75 mmol/g), and activity in converting >95% used frying oil (48 wt.%) over SZr/Ag, SZr/Ti, and SZr/W. This is outstanding considering the lower reaction parameter of 5 h, 5:1 methanol-to-oil ratio, and 200 °C compared to prior arts. Evidently, structure and strength of Bronsted acids have direct effect on the catalytic activity of the materials. This study also illustrated prospects of converting wastes into biodiesel, which is important especially against the backdrop of the current plummeting price of Brent crude oil.

Here, we report the upgrading of shea butter to biodiesel with hierarchical mesoporous ZSM-5 zeolites (HMZeol). Shea butter is a triglyceride (mainly oleic and steric acid) extracted from African shea tree nut. The catalysts synthesis was by desilication of conventional ZSM-5 with an aqueous solution of NaOH (0.3 and 0.4 M). XRF, XRD, NH3-TPD and N2 adsorption unveiled the effect of desilication of the parent zeolite. The study investigated the effect of NaOH concentration on matrix area, pore size, mesopore volume and Si/Al ratio. HMZeol showed superior activity on biodiesel yield when compared with the parent ZSM-5 zeolite. The catalytic material treated with 0.4 M NaOH (0.4HMZeol) gave 74% biodiesel yield at 5:1 methanol/oil molar ratio, 1 wt% catalyst, and 200 ᵒ C for 3 h reaction time while ZSM-5 gave 46.05% yield under the same reaction conditions. Further increase in the reaction time to 12 h for 0.4HMZeol, 0.3HMZeol and ZSM-5 gave 82.12, 79.21, and 72.13% biodiesel yield respectively. These results showed that hierarchical mesoporous HZSM-5 is a promising solid acid catalyst for biodiesel production via methanolysis.

Highly efficient, robust and mesoporous sulfated zirconia, SZ catalysts were prepared by co-precipitation and incipient-wetness routes with sufficient and in-excess acid. The study investigated the effect of pH, precursor type, and concentration, on SZ and compared their acidity and performance with ytterbium-doped SZ toward transesterification. N2 sorption, elemental analysis, XRD, and ammonia temperature-programmed desorption (NH3-TPD) revealed the properties of the catalytic materials. The specific surface area increases independently of the presence of Ti up to 60.33 m2/g, with increasing pH while pore size of the tetragonal crystallites decreases from 37.04 to 6.83 nm. Soaking the material in sufficient 0.5-M H2SO4 produced 37.04 nm SBET in contrast to 21.21 nm from soaking in excess. Double sulfation ensured sulfate incorporation while moderate precursor amounts enhanced activity of the materials. Interestingly, despite low specific surface area, which was due to short aging period, large mesoporosity, high amount, and dispersion of active sites on Yb-doped SZ, SZr-Ti-Yb-500-4/s ensured remarkable activity. The catalyst converted ca. 99% of used frying oil containing ca. 48 wt. % FFA. Consequently, this highlights the prospect of producing biodiesel at lower cost especially with current dwindling price of crude oil.

The activity of zeolite supported fluoride-ion functionalized molybdenum-oxalate catalyst (FMoOx/Zeol) and its kinetic study on the hydrodeoxygenation (HDO) of oleic acid (OA) is presented in this report. The FMoOx/Zeol was synthesized via simple dissolution method and characterized. The results revealed formation of highly reactive octahedral Mo species with enhanced textural and morphological properties. The FMoOx/Zeol activity on the HDO of OA at the best observed experimental conditions of 360°C, 30 mg FMoOx/Zeol and 20 bar produces 64% n-C18H38 and 30% iso-C18H38 in 60 min. The acidity of FMoOx/Zeol was responsible for the production of the iso-C18H38. The kinetic data showed that sequential hydrogenation of OA into stearic acid (SA) was faster than the HDO of SA into biofuel with activation energies of 98.7 and 130.3 kJ/mol, respectively. The reusability studies showed consistency after three consecutive runs amounting to 180 min reaction time. The results are encouraging towards industrial application.

A B S T R A C T Optimization of hydrodeoxygenation (HDO) of oleic acid (OA) into paraffinic biofuel using zeolite supported fluoroplatinum oxalate (FPtOx/Zeol) catalyst is reported in this study. FPtOx/Zeol was synthesized via incorporation of HF modified oxalic acid (OxA) functionalized K2PtCl4 into zeolite A support. FPtOx/Zeol was characterized and the results showed highly dispersed tetrahedral and octahedral Pt species which are effective for sequential hydrogenation of the unsaturated OA bond and the HDO of OA, respectively. Furthermore, there was increase in Si/Al ratio of FPtOx/Zeol leading to loss of crystallinity due to dealumination of the extra framework and framework alumina as a result of acid attacks and calcination, respectively. FPtOx/Zeol activity was tested on the HDO of OA in a semi-batch reactor and the process parameters were optimized using validated quadratic models. The optimum conditions were 364 8C, 18 bar and 27.8 mg FPtOx/Zeol loading under reaction time of 58 min to produce 28.39% iso-C18H38 and 68.93% n-C18H38. The presence of the isomerized product was due to the combine effect of fluoride ion and oxalic acid functionalization on the catalyst. FPtOx/Zeol reusability studies showed consistency after three consecutive runs. These results are promising for further research toward commercialization of biofuel production.