Functionalization of biphenylcarbazole (CBP) with siloxane-hybrid chains for solvent-free liquid materials

Funding: This research was funded by the French National Research Agency (ANR) through the Programme d’Investissement d’Avenir under contract ANR-11-LABX-0058-NIE within the Investissement d’Avenir program ANR-10-IDEX-0002-02 and was supported by Khalifa University through the grant RC2-2018-024.We report herein the synthesis of siloxane-functionalized CBP molecules (4,4′-bis(carbazole)-1,1′-biphenyl) for liquid optoelectronic applications. The room-temperature liquid state is obtained through a convenient functionalization of the molecules with heptamethyltrisiloxane chains via hydrosilylation of alkenyl spacers. The synthesis comprises screening of metal-catalyzed methodologies to introduce alkenyl linkers into carbazoles (Stille and Suzuki Miyaura cross-couplings), incorporate the alkenylcarbazoles to dihalobiphenyls (Ullmann coupling), and finally introduce the siloxane chains. The used conditions allowed the synthesis of the target compounds, despite the high reactivity of the alkenyl moieties bound to π-conjugated systems toward undesired side reactions such as polymerization, isomerization, and hydrogenation. The features of these solvent-free liquid CBP derivatives make them potentially interesting for fluidic optoelectronic applications.Peer reviewe

Synthesis and performance evaluation of hydrocracking catalysts: a review

This review provides a comprehensive summary of current hydrocracking applications, and presents recent advances in the synthesis and structure/composition control of various nanomaterials used in hydrocracking catalysts. Although a wide range of feeds are considered in this review, particular focus is placed on hydrocracking of aromatic and paraffinic compounds. The significance, concepts and principles of the hydrocracking process are first discussed focusing on its wide range of industrial applications. Then, recent advances in the synthesis of hydrocracking catalysts are presented, including different types of zeolites and metal promoted catalysts. Finally, we compare the performances of a wide range of hydrocracking catalysts, and discuss how their intrinsic properties (e.g. surface area, porosity, acidity, morphology and structure) can be controlled to achieve optimal catalytic performance in hydrocracking of aromatic compounds, heavy petrochemicals, paraffinic hydrocarbons and vegetable oils

Ni Catalysts Based on Attapulgite for Hydrogen Production through the Glycerol Steam Reforming Reaction

Attapulgite (ATP, a natural clay) was used as carrier to produce a nickel-based catalyst (Ni/ATP) for the work that is presented herein. Its catalytic performance was comparatively assessed with a standard Ni/Al2O3 sample for the glycerol steam reforming (GSR) reaction. It was shown that the ATP support led to lower mean Ni crystallite size, i.e., it increased the dispersion of the active phase, to the easier reduction of NiO and also increased the basicity of the catalytic material. It was also shown that it had a significant effect on the distribution of the gaseous products. Specifically, for the Ni/ATP catalyst, the production of liquid effluents was minimal and subsequently, conversion of glycerol into gaseous products was higher. Importantly, the Ni/ATP favored the conversion into H2 and CO2 to the detriment of CO and CH4. The stability experiments, which were undertaken at a low WGFR, showed that the activity of both catalysts was affected with time as a result of carbon deposition and/or metal particle sintering. An examination of the spent catalysts revealed that the coke deposits consisted of filamentous carbon, a type that is known to encapsulate the active phase with fatal consequences

Solar light responsive bismuth doped titania with Ti\u3csup\u3e3+\u3c/sup\u3e for efficient photocatalytic degradation of flumequine: Synergistic role of peroxymonosulfate

© 2019 Elsevier B.V. The present study is focused on the synthesis of a novel solar light responsive bismuth doped titania (Bi-TiO2) through a facile so-gel technique by applying various wt% of Bi. The as-synthesized Bi-TiO2 showed superior photocatalytic performance than un-doped TiO2 towards degradation of flumequine (FLU) under solar light irradiation. The as-synthesized material was thoroughly characterized to examine its structure, morphology and chemical states. The EPR analysis revealed the existence of Ti3+ ion and oxygen vacancy, which is created due to Bi-doping. The as-synthesized Bi-TiO2 with 5 wt% Bi (TBi5) showed excellent photocatalytic performance as compared to their counterparts. The photocatalytic activity of TBi5 was further improved when added with peroxymonosulfate (HSO5−) and increased with increasing [HSO5−]0. The mechanistic investigation and radical scavenging studies revealed that [rad]OH and SO4[rad]− are involved in the degradation of FLU by the as-synthesized material. The bimolecular rate constants of [rad]OH and SO4[rad]− were calculated to be 9.1 × 109 M−1s−1 and 8.5 × 109 M−1s−1, respectively. The photocatalytic performance of the as-synthesized TBi5 coupled with HSO5− under solar light irradiation towards degradation of FLU in Milli-Q water (MW), tape water (TW) and synthetic wastewater (SWW) was 92, 82 and 70% with kapp values of 0.093, 0.085 and 0.066 min−1, respectively. Furthermore, the degradation pathways of FLU were predicted on the basis of its degradation products (DPs). The high mineralization of FLU as well as the evaluation of non-toxic DPs suggests that solar light/TBi5/HSO5− is a promising advanced oxidation process for the future wastewater treatment applications

Efficient removal of norfloxacin using nano zerovalent cerium composite biochar-catalyzed peroxydisulfate

Norfloxacin (NOR), an important antibiotic used for the treatment of different infections which is reportedly causing huge quantity of water pollution and severe environmental issues. In this study, biochar prepared from Phoenix dactylifera roots biomass (PB) and composited with mesoporous nano-zerovalent cerium (nZVCe) was used for treatment of NOR solutions. The various characterization and treatment studies showed successful formation of the nZVCe and PB composite. The nZVCe was found to improve physiological characteristics and catalytic efficiency of PB. The nZVCe/PB composite caused 52% removal of NOR as compared to 23% by the individual PB. The use of peroxydisulfate (PDS) with PB and nZVCe/PB showed further improvement in the removal of NOR and caused 58 and 84% removal efficiencies of NOR by PB/PDS and nZVCe/PB/PDS, respectively. The use of PDS with PB and nZVCe/PB was found to yield ●OH and SO4 ●– which improved degradation of NOR, however, addition of ●OH and SO4 ●– scavengers impeded NOR degradation. The PB was found to have several oxygen functional groups which decomposed PDS into ●OH and SO4 ●–. The nZVCe/PB showed high recovery, reusability, and stability and caused high removal of NOR even at fifth cycle of treatment both in the absence and presence of PDS. The treatment of NOR by nZVCe/PB-catalyzed PDS showed encouraging results under different pH, and varying concentrations of PDS, nZVCe/PB, and NOR as well as in real water samples which suggest potential practical applications of NOR contaminated water. Degradation of NOR resulted into several products and the resulting final product proved to be non-toxic

Deep eutectic solvent-mediated synthesis of ceria nanoparticles with the enhanced yield for photocatalytic degradation of flumequine under UV-C

© 2019 Elsevier Ltd This study investigated the use of a deep eutectic solvent (DES) for promoting the yield and stability of ceria nanoparticles used for the degradation of flumequine (FLU) under UV-C irradiation. The characterization by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, high resolution transmission electron microscopy, thermogravimetric analysis, and BET surface area analysis revealed the synthesis of highly stable, highly crystalline, and mesoporous ceria nanoparticles using DES which led to the high removal, i.e., 50 % and 94 % of FLU using DES-Ceria and UV-C/DES-Ceria, respectively. Removal of FLU by the UV-C mediated ceria nanoparticles was due to [rad]OH and thus factors that influenced the reactivity and yield of [rad]OH retarded the removal efficiency of FLU. The pH of aqueous solution affected the removal of FLU by the photocatalysts and removal of FLU was inhibited at highly alkaline and acidic pH. The degradation pathways of FLU were established from the pattern of its degradation and nature of the degradation products. Acute and chronic toxicities of FLU as well as its products were measured. The photocatalyst synthesized in DES was found to be environmentally benign and showed significant potential in the remediation of FLU

Synthesis of nitrogen-doped Ceria nanoparticles in deep eutectic solvent for the degradation of sulfamethaxazole under solar irradiation and additional antibacterial activities

© 2020 Elsevier B.V. In this study, highly crystalline, mesoporous, small sized, stable, and efficient nitrogen-doped (N-doped) Ceria nanoparticles were synthesized using deep eutectic solvent (DES) and used for the photocatalytic degradation of sulfamethaxazole (SMX), a widely used human medication and emerging water contaminant. The N-doped Ceria resulted in 96% removal of SMX versus 59% by Ceria under solar irradiation at 150 min time using [SMX]0 = 10 mg/L and [Ceria]0 = [N-doped Ceria]0 = 0.5 g/L. The solar irradiation of the photocatalysts produced [rad]OH which was proved with electron spin resonance (ESR) spectroscopy and radical scavenger studies and the resulting [rad]OH caused the degradation of SMX. The [rad]OH showed high second-order rate constant with SMX, e.g., 4.9 × 109 M−1 s−1. The photocatalytic degradation of SMX was influenced by pH, concentrations of SMX and photocatalysts, inorganic anions, and natural organic matter. The kinetics of the photocatalytic degradation of SMX was found to be pseudo-first-order. The SMX degradation resulted into several products which were identified by UPLC-MS/MS and the resulting products were used to establish degradation pathways of SMX. The synthesized Ceria and N-doped Ceria also showed good antimicrobial activities towards Staphylococcus aureus and Escherichia coli. The treatment of SMX showed high reusability of N-doped Ceria, low leaching of cerium ions into reaction solution, and high decline in toxicity of SMX which suggests high potential of the synthesized nanoparticles towards SMX degradation

Synergistic effects of activated carbon and nano-zerovalent copper on the performance of hydroxyapatite-alginate beads for the removal of As\u3csup\u3e3+\u3c/sup\u3e from aqueous solution

© 2019 Elsevier Ltd In this study, activated carbon (AC) and nano-zerovalent copper (nZVCu) functionalized hydroxyapatite (HA) and alginate beads were synthesized and used for the removal of As3+ from aqueous solution. The characterization by X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, high resolution transmission electron microscopy, BET surface area analysis, thermogravimetric analysis, and Fourier transform infrared spectroscopy revealed successful formation of the AC/nZVCu/HA-alginate, nZVCu/HA-alginate, AC/HA-alginate, and HA-alginate beads. The scanning electron microscopy and surface analysis revealed the prepared beads to be highly mesoporous which led to the maximum adsorption of As3+, i.e., 13.97, 29.33, 30.96, and 39.06 mg/g by HA-alginate, AC/HA-alginate, nZVCu/HA-alginate, and AC/nZVCu/HA-alginate beads, respectively. The thermogravimteric analysis showed the nZVCu/HA-alginate beads to be highly stable while the AC composite beads as the least stable to heat treatment. The HA-alginate beads achieved 39% removal of As3+, however, removal efficiency was promoted to 95% by coupling AC and nZVCu with HA-alginate beads at a reaction time of 120 min. The removal of As3+ by the prepared AC & nZVCu coupled HA-alginate beads was promoted with increasing [As3+]0 and [AC/nZVCu/HA-alginate]0. The pH of aqueous solution significantly influenced the removal of As3+ by AC/nZVCu/HA-alginate beads and maximum removal was achieved at pH 5.8. Freundlich adsorption isotherm and pseudo-second-order kinetic models were found to best fit the removal of As3+ by the synthesized beads. The high performance of AC/nZVCu/HA-alginate beads in the removal of As3+ even after seven cyclic treatment as well as least leaching of Cu ions into aqueous solution suggest enhanced reusability and stability of HA-alginate beads by coupling with AC and nZVCu. The results suggest that the synthesized beads have good potential for the removal of As3+ from aqueous solutions

Selective catalytic deoxygenation of palm oil to produce green diesel over Ni catalysts supported on ZrO2 and CeO2–ZrO2: Experimental and process simulation modelling studies

The selective deoxygenation of palm oil to produce green diesel has been investigated over Ni catalysts supported on ZrO2 (Ni/Zr) and CeO2–ZrO2 (Ni/CeZr) supports. The modification of the support with CeO2 acted to improve the Ni dispersion and oxygen lability of the catalyst, while reducing the overall surface acidity. The Ni/CeZr catalyst exhibited higher triglyceride (TG) conversion and yield for the desirable C15–C18 hydrocarbons, as well as improved stability compared to the unmodified Ni/Zr catalyst, with TG conversion and C15–C18 yield remaining above 85% and 80% respectively during 20 h of continuous operation at 300 oC. The high C17 yields also revealed the dominance of the deCOx (decarbonylation/decarboxylation) pathway. A fully comprehensive process simulation model has been developed to validate the experimental findings in this study, and a very good validation with the experimental data has been demonstrated. The model was then further utilised to investigate the effects of temperature, H2 partial pressure, H2/oil feed ratio and LHSV. The model predicted that maximum triglyceride conversion was attainable at reaction conditions of 300 °C temperature, 30 bar H2 partial pressure, H2/oil of 1000 cm3/cm3 feed ratio and 1.2 h−1 LHSV.MAG and NDC gratefully acknowledge that this researched was co-financed by Greece and the European Union (European Social Fund-ESF) through the Operational Programme “Human Resources Development, Education and Lifelong Learning” (MIS-5050170). KP and SA acknowledge the financial support from the Abu Dhabi Department of Education and Knowledge through the grant AARE-2019-233 and the support from Khalifa University through the grant RC2-2018-024. VS acknowledges the ICTS ELECMI-LMA for offering access to their instruments and expertise.Peer reviewe

Optimizing the oxide support composition in Pr-doped CeO2 towards highly active and selective Ni-based CO2 methanation catalysts

In this study, Ni catalysts supported on Pr-doped CeO2 are studied for the CO2 methanation reaction and the effect of Pr doping on the physicochemical properties and the catalytic performance is thoroughly evaluated. It is shown, that Pr3+ ions can substitute Ce4+ ones in the support lattice, thereby introducing a high population of oxygen vacancies, which act as active sites for CO2 chemisorption. Pr doping can also act to reduce the crystallite size of metallic Ni, thus promoting the active metal dispersion. Catalytic performance evaluation evidences the promoting effect of low Pr loadings (5 at% and 10 at%) towards a higher catalytic activity and lower CO2 activation energy. On the other hand, higher Pr contents negate the positive effects on the catalytic activity by decreasing the oxygen vacancy population, thereby creating a volcano-type trend towards an optimum amount of aliovalent substitution.AIΤ, NDC and MAG acknowledge support of this work by the project “Development of new innovative low carbon energy technologies to improve excellence in the Region of Western Macedonia” (MIS 5047197) which is implemented under the Action “Reinforcement of the Research and Innovation Infrastructure”, funded by the Operational Program “Competitiveness, Entrepreneurship and Innovation” (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund).Peer reviewe