Qatar Foundation Annual Research Forum Volume 2013 Issue 1

Methane steam reforming is a carbon-intensive process with high energy requirements. The addition of a CO2 sorbent in the reformer has been proposed as an alternative process to reduce heat demands (since the carbonation reaction is exothermic) and at the same time capture CO2, drive the thermodynamic equilibrium and obtain high-purity hydrogen. In a QNRF funded project, AUTH and TAMUQ are investigating sorption enhanced steam reforming combined with chemical looping. The process is called Sorption Enhanced-Chemical Looping Steam Methane Reforming and in addition to the sorbent, the reformer contains material which serves as an oxygen transfer material (OTM). The basic principle is shown in Fig.1. During the reduction step (reforming), the OTM is reduced by methane into metallic nickel, the active catalyst for endothermic methane reforming, and the reaction proceeds under near autothermal conditions due to heat released by sorbent carbonation. During the regeneration/oxidation step, the reduced OTM is re-oxidized, releasing significant amount of heat which drives the endothermic regeneration of the saturated sorbent. The key for successful commercialization of the process is development of stable sorbents and OTMs that can undergo multiple cycles of reaction/regeneration without deterioration in their performance. Herein, we report results from our studies on development of CaO-based mixed oxides CO2 sorbents. Mixed calcium oxides with alumina, zirconia, magnesia and lanthana were synthesized via the sol-gel autocombustion method using citric acid as a combustion agent. The mixed oxides were prepared with constant 66wt% concentration of free CaO and were characterized by BET and XRD. Results showed that CaO is formed in all cases, accompanied by formation of mixed Ca3Al2O6 and CaZrO3 in Ca-Al and Ca-Zr sorbents, respectively. On the contrary no mixed phase was formed between CaO and Mg or La. The sorption capacity and stability of the sorbents were tested in a TGA instrument (or unit) for 100 consecutive sorption-desorption cycles under 15% CO2 in N2 for 30 minutes at 650°C and 100% N2 for 5 minutes at 850°C. The CO2 capacity of all the synthesized sorbents as a function of a number of cycles is shown in Fig.2. The highest CaO conversion was obtained with Ca-Al (99.8%), followed by Ca-Zr, Ca-Mg and Ca-La. The most stable material proved to be Ca-Zr with only 13.7% loss of capacity after 100 cycles. Ca-Al also had a promising performance with 20.7% loss, while Mg and La both exhibited significant deactivation (i.e.  30% loss in sorption capacity). The two most promising materials (Ca-Al and Ca-Zr) were also synthesized using a different combustion agent, triethanolamine, to investigate the effect of an organic fuel. The use of TEA was beneficial for Ca-Zr,which achieved higher CaO conversion (96.9%) and better stability (13.4% loss), while the opposite trend was observed for Ca-Al. Overall among all investigated CO2-sorbents, Ca-Al and Ca-Zr prepared with both citric acid and triethanolamine as combustion agents, exhibited excellent initial capacity and stability, with a sorption capacity higher than 9 mol CO2/kg of sorbent after 100 sorption-desorption cycles under relatively mild operating conditions.

The rejection efficiency of boron by RO membranes is poor, especially when a large proportion of boron in feedwater exists as uncharged boric acid which can diffuse through most of the available RO membranes.1,2 Among the methods suggested for boron removal from water and wastewater, adsorption is a very useful and economical technique. Magnetic adsorbents containing chelating precursors that are selective for boron have been used as a smart, fast and simple method for the separation and pre-concentration of boron3. After adsorption, the adsorbents can be isolated from the medium by simple magnetic separation. Here, we present novel magnetic nanocomposites for the selective removal of boron from seawater. The nanocomposites have been synthesized and fully characterized using scanning electron microscopy (SEM), tunneling electron microscopy (TEM), Fourier transformed infrared (FTIR) and powder x-rat diffraction (PXRD). This technology provides a simple method for the adsorption of boron and separation of magnetic nanoparticles from a solution using an easy magnetic procedure. The effect of different nanosorbents, sorbent amount and pH on the sorption of boron was studied. The magnetic sorbent that provided the highest boron sorption efficiency was used for the subsequent experiments investigating the most effective magnetic sorbent amount and pH for the sorption of boron. Experimental results indicate that boron sorption increases with increasing sorbent dosage up to a sorbent amount of approximately 0.6 g, after which the difference in removal efficiency was found to be negligible. The effect of pH on boron removal efficiency using the nanosorbents was studied at initial boron concentrations of 4-5 ppm, amounts commonly found in seawater. The sorption of boron was found to be highest at a pH range of 7-7.5 with a sorption efficiency of 77.6 ± 1%.

Pollution, due to activities related to the oil industry, represents a serious threat to the natural environment. The application of biotechnological methods provides much safer and sustainable alternatives for bioremediation of polluted areas, using microorganisms. Several techniques for the isolation of hydrocarbon degrading bacteria have been investigated and published worldwide. A wide range of biological activities was shown. However, local hydrocarbon degrading strains and the factors affecting bacterial and strains variability were not studied deeply. In this study, we showed that the isolation and screening strategy affected a lot, the selection of the strains. We combined the bacterial tolerance to hydrocarbon toxicity, assessed by the growth parameters, and the bacterial degradative activities, assessed by the degradation of a wide range of petroleum hydrocarbons via gas chromatography analysis. The main investigations and findings of the present work are:  A collection of 39 bacterial isolates from Qatari polluted soil was set up and a new isolation and screening program was proposed.  The growth conditions and the activity of pre-selected strains  Shift of the activity of the selected strains from a range of hydrocarbons to another by the effect of the nitrogen source, C/N ratio and organic nitrogen source  70% hydrocarbon removal, achieved with several strains in 2 weeks.  Amongst 12 identified isolates and by molecular ribotyping-DNA sequencing, 3 strains of Pseudomonas genus were isolated from a polluted soil in Qatar, are available for bioremediation of highly polluted soils, tolerating high toxicity and may be adapted to a variety of low or high molecular weight hydrocarbons.

Migration of phthalates into bottled water

Reactive Nanoparticle-Supported Dead-End Flow Ultrafiltration for Removal of Mercury from Water: Effect of Solution Composition

Anchu Ashok*, Arya Arackal, George Jacob, Gargi Raina Centre for Nanotechnology Research, VIT University, Vellore, India - 632014 * [email protected] Keywords: Surface Plasmon, Localization, Propagating surface plasmon, Coupling. Surface Plasmons (SPs) are collective electron oscillations at metal dielectric interface. They are often categorized into localized surface plasmon resonance and propagating surface plasmon resonance (PSPR). LSPR are non propagating electromagnetic waves and PSPR are propagating. In this work, we have carried out a study of Electric Field Intensity variation for different isolated and array structures of Au and Ag for corresponding plasmonic wavelength. Double plasmon resonance peak are observed, which is the combined effect of localized surface plasmonic resonance (LSPR) and propagating surface plasmonic resonance (PSPR). Shape, size and thickness of the structures affect Localized surface plasmonic resonance while as propagating surface plasmonic resonance (PSPR) is dependent on the 1D and 2D arrangements of the patterns. Depending on the sharp and confined corners, density of the hot spot in structures changes. Hence, triangular structure gives more excitation when compared with circle, square and ellipse. This work followed triangular patterns to find the coupling effect of LSPR and PSPR depend on the arrangement of patterns. Incident TM polarized plane wave of wavelength from 300 nm to 1000 nm with electric field intensity 1V/m was given for finding the enhancement of electric field in the patterns. Sharper the corners, more is the electric field enhancement. Another important factor affecting the enhancement of electric field is the grating period. If distance of two adjacent corners decreases, the coupling between the localized surface plasmons increases. This increase in coupling leads to the propagating electromagnetic wave called propagating surface plasmons (PSPs). This coupling distance depends on the propagation length of electric field from one structure to another. If the second structure is placed at a distance less than that of the propagation length there is an effective coupling of the electric field from one structure to another. This work discusses about simulation of electric field intensity for three types of patterns with the variation on their period and confinement employing Finite Element Method (FEM). Double resonance peak are noticed in all structures is due to the coupling effect of field from one structure to another and there is change in field enhancement and resonance wavelength with different patterns. Resonance wavelength due to the PSPR is at longer range and that of LSPR is at shorter range. Propagating surface plasmon resonance wavelength is same for a particular structure irrespective of number of structures in the array. Spectral separation between the LPSR peak and PSPR peak can be modified by changing the period and confinement in the structures. Silver patterns show better enhancement than gold patterns. The enhancement of Gold patterns is in near IR range and that of Silver is in visible range. Combined effect of this LSPR and PSPR give drastic field enhancement which makes these patterns as good substrate candidate for Surface Enhanced Raman Spectroscopy and biosensors.

I. INTRODUCTION The utility-scale Photovoltaic (PV) system experienced a tremendous growth to satisfy the fast increase of world's power demand. Nowadays, focus has been placed on innovative and cheap inverter solutions and system configurations. Among them, The Cascaded Multi-level Inverter (CMI) structure is more preferable to reach utility-scale power ratings and medium-voltage levels due to transformer-less, small size, high efficiency, high power density, and low cost. However, due to lack of boost function, the traditional CMI will lead to overrating the inverter by a factor of two to cope with wide (1:2) PV voltage variations. The recently proposed quasi-Z-source CMI (qZS-CMI) structure provides attracting improvement by combing the quasi-Z-source network into the traditional CMI. In addition to the advantages of traditional CMI, the qZS-CMI provides buck/boost function in a single-stage inverter topology, the independent dc-link voltage balance, and the one-third module reduction. All of those will bring positive effects on the system volume, efficiency, and cost. Contributions of this paper are proposing a high-power PV system based on qZS-CMI, which is 1-MW power and 11-kV voltage with 16 cascaded quasi-Z-source H-Bridge inverter (qZS-HBI) modules per phase. In this way, the high-power system can be fulfilled by low-power-low-frequency devices, aiming at the proposed PV system of low cost, high efficiency and reliability, and high performance-cost ratio, thus to improve the scientific and economic developments of Qatar. II. METHODS AND RESULTS The proposed system was simulated in MATLAB / Simulink by: 1) Sixteen cascaded quasi-Z-source H-Bridge inverter modules per phase. 2) Each qZS-HBI is fed by separate PV panels. 3) The phase-shifted sinewave pulsewidth modulation is applied to synthesize the multilevel voltage waveform. 4) Next step is to design the control scheme of the system with maximum power point tracking, grid-tie injection, novel modulation, etc.. ACKNOWLEDGEMENT This work was supported by NPRP-EP No. X - 033 - 2 - 007 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.

Vehicles at Qatar university road networks are subject to pass through multiple roundabouts and intersections in order to reach their destination. Since the traffic volume is relatively low, unsignalized controlled intersections are used to regulate the flow of vehicles (sign-controlled) .T shaped intersections and multiple lane roundabouts are utilized throughout Qatar University closed loop system. This study has been conducted to measure the current performance of some unsignalized intersections at Qatar University roads. Two roundabouts and one TWSC intersection were selected for the study. The methods presented in the Highway Capacity Manual (HCM 2000) were employed in this study and were used to compute the various approaches and movements capacities and the related performance measures .e.g. Control Delays (s), Queue lengths (veh ) and Level of service (LOS). To this end we will base our capacity analysis on Gap acceptance method and on simple, empirical, lane-based, regression model for multiple lane roundabouts. Data inputs collected for the selected method involved the critical traffic volumes (veh/hr) which occur in the peak hour .15 peak minute flow rates were recorded to obtain the peak hour flow rates. In addition the methods were used to make future projection of the capacities and the related performance measure based on forecasted demand in 2022. The results show that the current performance of the roundabouts is satisfactory for which the Level of service was graded A for all approaches in the two roundabouts given that the computed delays never exceeds 10 s / vehicle in any approach. The current results for the roundabouts coincide with the actual performance of the intersections where very little delays are encountered while driving and very short queues are formed during the peak hour. Regarding the T intersection the performance of the Left turn of the major street was found satisfactory and was graded A while the performance of the shared lane of the minor road was graded C. Based on forecasting results, the increase in entry and conflicting flow rates have resulted in decreasing the expected capacities of the various approaches on the studied intersections. In general for the roundabouts no significant difference in performance is to be experienced in year 2022 when current demand is expected to experience over 50 % increase and still the performance will be satisfactory. The same conclusion was drawn for the Left turn movement from Major Street that no major difference in performance is projected in future. But this conclusion was not applicable on the shared lane where it was very much affected by the increase in demand and the performance has rapidly dropped from its current level.

Meeaad Y. Al-Jassim1, Noof M. Al-Korbi1, Fatima A. Al-Naemi1 1Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, Doha, Qatar The mycobiota of soil was investigated in ninety soil samples collected from three different localities in Qatar, biology field2, biology field 3 and University farm. Biology field 2 and biology field 3 are located at longitude and latitude 549350.32 M.E and 2866180 M N 3 549812.00 ME and 2806702.93 M N respectively. Qatar University farm is located in Raodat Al Faras, about 60 km north of Doha (49° 25´ N, 20° 51´ E), 14.1 meters above sea level, with an area of 54.3 ha. Soil samples were collected under Zygophyllum quatarense, which was dominated in biology field 2 and 3 and from rhizosphere of fig, lemon, and date palm trees in QU farm. Twenty nine species of fungi belong to 9 genera were isolated from Biological field 2 and 3 at Qatar University. Whereas 19 fungal species belonging to 10 genera were isolated from QU farm. The distribution of soil borne was affected by the microclimate, physic-chemical propriety of soil and types of vegetation. The genus of highest incidence and their respective numbers of species was, Rhizopus ( 24 %, 3 species) isolated from biology field 2 and 3. The genus of lowest incidence was (Aspergillus (4.5 %, 2 species) islolated from biology field 2 and 3. Whereas, Aspergillus was the most common genera(43.78%, 18 species) isolated from QU farm followed by Rhizopus (13.4 %, 4 species) and Trichoderma (7.7 %, 2 species). Sixteen isolates were shown an antagonistic activity. Alternaria chlamydospora showed highest percentage of antagonistic activity against many species. In contrast, introduction of Rhizopus arrhizus led to approximately 62.5% reduction in Alternaria chlamydospra growth. Moreover, Penicillium griseofulvum inhibited the growth Alternaria chlamydospra by 10%. Keywords: Soil borne fungi, antagonist, microclimate, biological control