Herein we introduce an effective approach for incorporating sulfamic acid (SA) into HKUST-1. The synthesized materials have been characterized using XRD, XPS, BET, FT-IR, SEM, EDX and TEM. The X-ray ...diffraction pattern of SA@HKUST-1 is analogous to that of parent HKUST-1 in line shape and
d
-spacing, proving that chemical modification could be obtained without damage to structural solidity. The XPS spectra confirmed successful sulfonation, due to the single S 2p peak being attributable to SO
3
H groups at 168 eV. Catalytic efficiency was studied for 7-hydroxy-4-methyl coumarin and 3,4-dihydropyrimidinone synthesis and it was found to be highly dependent on the amount of SA loaded over HKUST-1. Moreover, the adsorptive removal activity of some common organic and inorganic pollutants from water has been studied. To fully understand the adsorption process, the effects of initial dye concentration, pH of solution, adsorbent dosage, contact time and temperature on the adsorption process were successfully studied. Under the optimum conditions 10 wt% SA@HKUST-1 was able to reach the maximum adsorption capacity for Pb
2+
(298 mg g
−1
) and Malachite green (290 mg g
−1
). Hopefully, this will facilitate research on improving the prospective use of MOFs for future applications.
Herein we introduce an effective approach for incorporating sulfamic acid (SA) into HKUST-1.
A facile co-precipitation technique, including in-situ reduction of graphene oxide (GO), is used to synthesize rGO/CuS nanocomposites. The photocatalytic performance of CuS was enhanced by loading ...reduced graphene oxide (rGO). Several instrumentations depicted the obtained nanostructures. The photocatalytic performance of the rGO/CuS nanocomposites was evaluated, for the first time, to eliminate malachite green (MG) dye under direct sunlight radiance. The experimental results revealed that the (rGO/CuS-7) composite achieved the highest efficiency of 97.6% for MG after exposure to sunlight for 90 min Also, the photocatalyst could recycle for five times without any loss in the activity. The result showed that rGO/CuS has the highest total organic Carbon (76%) compared to the published reports for the photodegradation of MG. The research outcomes develops a new one-pot synthesis avenue to prepare a promising rGO/CuS nanocomposites for the photocatalytic degradation of organic contaminants under direct sunlight.
•rGO/CuS was prepared via in-situ reduction of GO and Cu ions throught a co-precipitation method.•A full characterization of the produced composite confirmed the synthesis of rGO grafted with CuS.•For the first time, rGO/CuS photocatalyst was used for the photodegradation of malachite green.•rGO/CuS photocatalyst exhibited a superior activity towards (MG) dye under direct sunlight.•The result showed that rGO/CuS has a highest total organic carbon for the photodegradation of MG.
The recent deployment of distributed generation has led to a revolution in the use of distribution systems and the emergence of "smart grid" concepts. Smart grids are intended primarily as a means of ...facilitating the integration of renewable energy sources and of achieving greater system reliability and efficiency. Energy storage systems (ESSs) offer a number of benefits that can help utilities move toward those goals. One of those benefits is the capacity to improve the utilization of network infrastructure by means of proper load management. This paper proposes a methodology for allocating ESSs in distribution systems in order to defer system upgrades, minimize system losses, and take advantage of the arbitrage benefit. The cost and arbitrage benefit of energy storage installation are optimized with respect to system upgrade and energy losses costs. The primary goal of this research is to determine the optimal size and location of storage units to be installed, in addition to their optimal operation, so that total system costs are minimized, while system benefits are maximized. In this paper, a probabilistic load model is adopted instead of utilizing time-series based models, which provide an optimal solution that is valid only for the time-series pattern that is applied.
Most line faults in microgrids are temporary and are cleared shortly after the fault inception using an auto-reclosing (AR) scheme. However, there are limitations to the AR activation in ...generation-ended lines of microgrids because reclosing on a permanent fault may cause severe electrical and mechanical stress to generators and turbines. On the other hand, reducing the generator outage time caused by temporary faults is important, especially for distributed generators (DGs), because they significantly affect voltage control and grid stability. In this article, a three-phase adaptive AR scheme for wind farms equipped with doubly-fed induction generators (DFIGs) is presented. The dead time of the proposed method is adaptive and can be set at a minimum value considering the fault condition. The DC-link capacitor of the DFIG converters is used to generate diagnostic pulses to ensure fault clearance. This AR scheme helps to reduce the power generation outage time. Also, it prevents reclosing during permanent faults using active fault detection. Simulations and experimental tests are conducted to evaluate the efficiency of the proposed scheme.
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TiO2 and Sn+4 doped TiO2 nanoparticles were prepared via the surfactant-assisted sol-gel method. Then, H3PW12O40 (PTA) was loaded over Sn-TiO2 nanoparticles with different PTA ...contents by wet impregnation method. The samples have been characterized by XRD, TEM, SEM, FTIR, UV–vis diffuse reflection (DRS) and photoluminescence spectroscopy (PL). The surface acidity was studied by potentiometric titration and the pyridine was used as probe molecules to distinguish between Brönsted and Lewis acid sites. XRD patterns analysis indicates that the crystallite size reduced remarkably with increasing PTA loading. TEM and SEM images exhibit irregular particles shape and the amount of PTA on the Sn-TiO2 surface increased with increasing PTA loading up to 60% wt. The addition of PTA and Sn+4 improved the surface acidity and catalytic activity of TiO2. Moreover, the addition of Sn+4 promoted the electrons transfer between PTA and TiO2 and reduced the recombination of electrons (e–) and holes (h+). The catalytic activity was tested by synthesis of 7-hydroxy-4-methyl coumarin and 14-phenyl-14H-dibenzo a,j xanthene. Both the acidity and catalytic activity increased sharply after modification Sn-TiO2 by PTA and the sample with 50 wt.% PTA showed the highest acidity and catalytic activity. Also, the photocatalytic performance of PTA/Sn-TiO2 was confirmed in the degradation of Methylene Blue (MB) and Rhodamine B (RhB) under UV–vis irradiations. The mineralization of MB and RhB were confirmed by Chemical oxygen demand (COD) and total organic carbon (TOC). The results indicate that 20% PTA/Sn-TiO2 showed the highest photocatalytic activity.
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•Fine-grain sediments, heavy metals concentrations, and dominance of benthic fauna increase upward.•Two main salinity-controlled benthic associations were identified based on ...clustering and nMDS.•Freshwater taxa, suspension-feeders, infauna, and diversity decreases in last 50 year sediments.•Vertical changes in the biotic and abiotic variables point to a steady increase in the anthropogenic input.•Further declining of equilibrium species is expected if no restoration programs implemented soon.
Global climate changes and anthropogenic pressures have altered many coastal ecosystems worldwide. To understand the consequences of these perturbations on the community structure of the benthic communities, the fauna and the sediments retrieved from a short core in the Manzala Lagoon, which is largest in the Nile Delta, were quantitatively analyzed. The 120 cm long-core represents 170 years. A significant ecosystem shift took place in the upper 41 cm of the lagoon sediments were attributed to hydrodynamic changes, associated with the construction of Aswan High-Dam, where heavy metals concentrations, Pollution Load Index (PLI), and fine-grain sediments were increased. Consequently, the community structure of the benthic fauna was dramatically changed. Currently, the benthic community is dominated by brackish and opportunistic taxa (e.g., Fulvia fragilis, Pirenella conica, Corbicula fluminalis, and Melanoidestuberculata). In contrast, the pre-impact community contains equilibrium freshwater species. These salinity-controlled communities were better characterized on both Bray-Curtis -based Constrained Clustering (CC) and non-Metric Multidimensional Scaling (nMDS). The faunal density and Dominance Index are higher in the top samples, which point either to anthropogenic disturbance or taphonomic (mechanical or chemical) distortion with depths. However, higher species richness in lower samples suggested that the mechanical distortion has not altered the original communities and point to anthropogenic drivers of the diversity loss. Further declining or even extinction of the equilibrium species in the future is expected if no restoration programs implemented soon. Furthermore, nMDS and RMA regression models showed that the distribution of benthic fauna is governed by abiotic factors (e.g., water salinity, metal concentrations, and sediment grain-size). The latter indicates that biotic traits of benthic fauna such as feeding-mode and life-habit are highly sensitive to minor environmental changes and thus can be used as a robust indicator in paleoenvironmental reconstructions.
This paper presents a planning model that utilizes mobile energy storage systems (MESSs) for increasing the connectivity of renewable energy sources (RESs) and fast charging stations (FCSs) in ...distribution systems (DSs). The proposed planning model aims at enabling high penetration levels of green technologies while minimizing the total DS cost that includes investment, operating, and emission costs. The proposed model determines the optimal MESS sizes and transportation schedules as well as the optimal sizes and locations of wind-based distributed generators (DGs), photovoltaic (PV) DGs, and FCSs. The model takes into account techno-economic and environmental factors in addition to the power variations of RESs, FCSs, and load demands. The proposed planning model is applied on two benchmark test systems (i.e., 33-bus and 69-bus DSs). To evaluate the efficacy of the proposed model, the results obtained from the model are compared to those obtained from a traditional planning technique. The comparison of the results demonstrates that the proposed model with MESSs successfully achieves a significant cost saving and increases the penetration levels of RESs and FCSs.
Smart grids have been emerging nowadays as an initiative to operate modern distribution systems in a more economic and efficient way. Energy storage systems (ESSs) are one of the promising ...technologies that can achieve the goals of smart grids via facilitating the connection of renewable sources, improving system reliability, and controlling the net demand through peak load shaving, etc. In this paper, a comprehensive planning framework is introduced for ascertaining the most cost effective siting and sizing of ESSs that maximize their benefits in distribution networks. A probabilistic approach is further adopted that includes the consideration of the stochastic nature of system components. Such approach allows determining the optimal operation of ESS at each load state. Moreover, contingency planning decisions, in the form of load points to be shed during contingencies, are identified through the approach proposed.
Solar steam generation (SSG) is a potential approach for resolving the global water and energy crisis while causing the least amount of environmental damage. However, using adaptable photothermal ...absorbers with salt resistance through a simple, scalable, and cost-effective production approach is difficult. Herein, taking advantage of the ultra-fast water transportation in capillaries, and the large seawater storage capacity of wood, we develop a highly efficient natural evaporator. The wood wastes (sawdust) were carbonized at low temperatures to fabricate a green and low-cost carbonaceous porous material (CW). To enhance the salt resistance in high saline water, this evaporator was coated with polyaniline emeraldine salt (ES-PANI) which was synthesized through facile and cost-effective one-step oxidation of aniline. Furthermore, the composite was decorated with silver sulfide to increase the evaporation rate which reached up to 1.1 kg m
−2
h
−1
under 1 sun irradiation with 91.5% efficiency. Besides, the evaporator performs exceptionally well over 10 cycles due to the salt resistance capability of ES-PANI which generates a "Donnan exclusion" effect against cations in saline water. The Ag
2
S@PANI/CW evaporator may be a viable large-scale generator of drinking water due to its high efficiency for energy conversion, simple and low-cost fabrication approach, salt-resistance, and durability.
Solar steam generation (SSG) is a potential approach for resolving the global water and energy crisis while causing the least amount of environmental damage.
In this study, zirconia-supported mesoporous MCM-41 composite was synthesized through the surfactant-assisted sol-gel technique. Then, different weight percentages of phosphotungstic acid (PTA) were ...loaded over Zr-MCM-41 composites by wet impregnation method. The composites were characterized by different techniques like TEM, XRD, FTIR, and N2 adsorption isotherms (BET). Potentiometric titration was used to study the surface acidity of the prepared catalysts, while pyridine adsorption was used as a probe molecule to distinguish between Brönsted and Lewis acid sites. Characterization techniques reveal that the insertion of PTA and ZrO2 improved the acidic strength and surface acidity of mesoporous MCM-41. The catalytic performance of the composites was studied through the synthesis of 7-hydroxy-4-methyl coumarin. Both catalytic activity and surface acidity raised sharply after addition of PTA and 25.0 wt% PTA/Zr-MCM-41 displayed the highest catalytic activity and surface acidity. As well as, the adsorption activity of PTA/Zr-MCM-41 composites was tested in the removal of Methylene Blue (MB) from an aqueous solution. Among the synthesized composites, 25.0 wt% PTA/Zr-MCM-41 has a maximum adsorption capacity equal 259.1 mg/g at pH = 10.0. The adsorption and kinetics data are well fitted with Langmuir isotherm model and pseudo-second-order model.
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•Different weight contents of phosphotungstic acid supported on ZrO2/MCM-41 composites were successfully synthesized.•25.0 wt% PTA/Zr-MCM-41 sample showed maximum catalytic activity in coumarin synthesis with percentage yield equal 97.2%.•The prepared composites displayed as an excellent adsorbent with maximum adsorption capacity equal 259.1 mg/g.
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