Mohamad Sahban Alnarabiji

Study of the antimicrobial activity of cyclic cation-based ionic liquids via experimental and group contribution QSAR model

Over the past decades, Ionic liquids (ILs) have gained considerable attention from the scientific community in reason of their versatility and performance in many fields. However, they nowadays remain mainly for laboratory scale use. The main barrier hampering their use in a larger scale is their questionable ecological toxicity. This study investigated the effect of hydrophobic and hydrophilic cyclic cation-based ILs against four pathogenic bacteria that infect humans. For that, cations, either of aromatic character (imidazolium or pyridinium) or of non-aromatic nature, (pyrrolidinium or piperidinium), were selected with different alkyl chain lengths and combined with both hydrophilic and hydrophobic anionic moieties. The results clearly demonstrated that introducing of hydrophobic anion namely bis((trifluoromethyl)sulfonyl)amide, [NTF2] and the elongation of the cations substitutions dramatically affect ILs toxicity behaviour. The established toxicity data [50% effective concentration (EC50)] along with similar endpoint collected from previous work against Aeromonas hydrophila were combined to developed quantitative structure-activity relationship (QSAR) model for toxicity prediction. The model was developed and validated in the light of Organization for Economic Co-operation and Development (OECD) guidelines strategy, producing good correlation coefficient R2 of 0.904 and small mean square error (MSE) of 0.095. The reliability of the QSAR model was further determined using k-fold cross validation.

The Band Structures of Single-Walled Carbon Nanotubes and ZnO Nanoparticles Used for Oil Recovery in Water Flooding System

A major challenge for the oil industry is increasing the oil recovery from reservoirs. Nanofluid injection with the aid of electromagnetic (EM) waves can improve oil recovery. Nanoparticles of zinc oxide (ZnO) were synthesised using a sol-gel method and characterised using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Nanofluids of SWCNT and zinc oxide (ZnO) were used in this oil recovery study. It was observed that curved antennae with magnetic feeders gave a 472% larger D-field signal than those without magnetic feeders. The Dmol3 simulations showed that the band gap of ZnO is 1.088 eV, and the band gap of the SWCNT was 0.326 eV. The particle sizes of the ZnO nanoparticles were in the range of 30-39 nm. FESEM and HRTEM images showed that the samples were highly crystalline, and the grain size increased as the temperature increased. As a result, these nanoparticles were suitable for the preparation of the nanofluid and oil recovery applications. Oil recovery using 0.001% (w/w) ZnO nanofluid and EM was 16.10 % of OOIP, and using 0.01% SWNT nanofluid yielded an oil recovery of 23 ROIP %. These results imply that injecting a ZnO oxide nanofluid of 0.001% w/w coupled with a curved antenna and magnetic feeders has the potential to improve oil recovery in waterflooding systems.

The Role of Surface Area of ZnO Nanoparticles as an Agent for some Chemical Reactions

Synthesising zinc oxide nanoparticles (ZnO-NPs) to get certain characteristics to be applied in Enhanced Oil Recovery (EOR) is still challenging to date. In this work, the importance of high surface area of ZnO nanoparticles as EOR agent was highlighted. A simulation on density of state (DOS), band structure and adsorption energy of hydrogen and nitrogen gases on the surface of ZnO was carried out; it is observed that from the band structure of the band gap value for ZnO is 0.808ev. For the ZnO, Zn 4s states contribute to conduction band and O 2p states contribute to valence band. ZnO-NPs were synthesised using the sol-gel method by dissolving zinc nitrate hexahydrate in nitric acid and varying the stirring time (1 and 24h) and sintering time (30 and 40 min). A microwave oven was used for annealing ZnO without insulating the samples in any casket. The results show that 30 and 40 min of annealing and stirring for 1 & 24 h influenced the morphology and size of ZnO-NPs. These parameters could be tailored to generate a range of nanoparticle morphology (flask and/with agglomerated nanoparticles in a corn shape) obtained by Field Emission Scanning Electron Microscope (FESEM) and hexagonal crystal, determined by X-ray diffractometer (XRD), with the mean size of 70.5 & 74.9 nm and a main growth at the peak (101). The prepared sample via stirring for 24h and sintering for 40 min was chosen to prepare ZnO nanofluid because it has the highest surface area (BET) among the rest of samples, 0.23 m2/g. 10% of Original Oil In Place (OOIP) was recovered successfully to prove that ZnO is a good candidate to be applied in some chemical reactions. Moreover, it was found that ZnO is a promising catalyst for ammonia synthesis based on the adsorption energy of hydrogen and nitrogen gases (-1.05 and-1.60 kcal/mol respectively).

Experimental study on electromagnetic-assisted ZnO nanofluid flooding for enhanced oil recovery (EOR)

Recently, nano-EOR has emerged as a new frontier for improved and enhanced oil recovery (IOR & EOR). Despite their benefits, the nanoparticles tend to agglomerate at reservoir conditions which cause their detachment from the oil/water interface, and are consequently retained rather than transported through a porous medium. Dielectric nanoparticles including ZnO have been proposed to be a good replacement for EOR due to their high melting point and thermal properties. But more importantly, these particles can be polarized under electromagnetic (EM) irradiation, which provides an innovative smart Nano-EOR process denoted as EM-Assisted Nano-EOR. In this study, parameters involved in the oil recovery mechanism under EM waves, such as reducing mobility ratio, lowering interfacial tensions (IFT) and altering wettability were investigated. Two-phase displacement experiments were performed in sandpacks under the water-wet condition at 95°C, with permeability in the range of 265–300 mD. A crude oil from Tapis oil field was employed; while ZnO nanofluids of two different particle sizes (55.7 and 117.1 nm) were prepared using 0.1 wt. % nanoparticles that dispersed into brine (3 wt. % NaCl) along with SDBS as a dispersant. In each flooding scheme, three injection sequential scenarios have been conducted: (i) brine flooding as a secondary process, (ii) surfactant/nano/EM-assisted nano flooding, and (iii) second brine flooding to flush nanoparticles. Compare with surfactant flooding (2% original oil in place/OOIP) as tertiary recovery, nano flooding almost reaches 8.5–10.2% of OOIP. On the other hand, EM-assisted nano flooding provides an incremental oil recovery of approximately 9–10.4% of OOIP. By evaluating the contact angle and interfacial tension, it was established that the degree of IFT reduction plays a governing role in the oil displacement mechanism via nano-EOR, compare to mobility ratio. These results reveal a promising way to employ water-based ZnO nanofluid for enhanced oil recovery purposes at a relatively high reservoir temperature.

Catalytic Hydrodeoxygenation of Rubber Seed Oil over Sonochemically Synthesized Ni-Mo/γ-Al2O3 Catalyst for Green Diesel Production

Hydrodeoxygenation is one of the promising technologies for the transformation of triglycerides into long-chain hydrocarbon fuel commonly known as green diesel. The hydrodeoxygenation (HDO) of rubber seed oil into diesel range (C15-C18) hydrocarbon over non-sulphided bimetallic (Ni-Mo/γ-Al2O3 solid catalysts were studied. The catalysts were synthesized via wet impregnation method as well as sonochemical method. The synthesized catalysts were subjected to characterization methods including FESEM coupled with EDX, XRD, BET, TEM, XPS, NH3-TPD, CO-chemisorption and H2-TPR in order to investigate the effects of ultrasound irradiations on physicochemical properties of the catalyst. All the catalysts were tested for HDO reaction at 350 °C, 35 bar, H2/oil 1000 N (cm3/cm3) and WHSV = 1 h-1 in fixed bed tubular reactor. The catalyst prepared via sonochemical method showed comparatively higher specific surface area, particles in nano-size and uniform distribution of particle on the external surface of the support, higher crystallinity and lower reduction temperature as well as higher concentration of Mo4+ deoxygenating metal species. These physicochemical properties improved the catalytic activity compared to conventionally synthesized catalyst for HDO of rubber seed oil. The catalytic performance of sonochemically synthesized Ni-Mo/γ-Al2O3 catalyst (80.87%) was higher than the catalyst prepared via wet impregnation method (63.3%). The sonochemically synthesized Ni-Mo/γ-Al2O3 catalyst is found to be active, produces 80.87 wt% of diesel range hydrocarbons, and it gives high selectivity for Pentadecane (18.7 wt%), Hexadecane (16.65 wt%), Heptadecane (24.45 wt%) and Octadecane (21.0 wt%). The product distribution revealed that the deoxygenation reaction pathway was preferred. Higher conversion and higher HDO yield in this study are associated mainly with the change in concentration ratio between oxidation states of molybdenum (Mo4+, Mo5+, and Mo6+) on the external surface of the catalyst due to ultrasound irradiation during the synthesis process. Consequently, the application of sonochemically synthesized non-sulphided catalysts favored mainly hydrodeoxygenation of diesel range hydrocarbon.

Controllable green synthesis of supported hollow NiO crystals with shape evolution from octahedral to novel truncated octahedral

A simple controlled synthesis method for supported hollow NiO crystals from an octahedral morphology to their different truncated shapes was successfully obtained by utilizing a facile wet-impregnation method through controlling the calcination temperature.