Materials and Energy Research Center

The substantial sludge, composed of organic compounds, was detected in sediments samples of Anzali wetland. Photocatalysts have a great potential for decomposing organic compounds. In the present research, an attempt was made to decompose the sludge of Anzali wetland using titanium dioxide nanoparticles (TiO2 NPs). For this purpose, Luzchem’s CCP-4 V photoreactor, which is equipped with 12 UV lamps, was used. The influences of UV intensity, TiO2 concentration and exposure time were investigated for the removal of sludge. The statistically analysis showed that exposure time was the most effective factor in removal of sludge. The results also revealed that 10-µg/L TiO2 after long-term exposure (5 days) would decompose about 37% of organic contents of sludge. Further detailed studies revealed that due to the decomposition of organics, about 2100, 1700, 1650, 270 and 181 µg/L of Sr, Mn, Si, Al and P would be released into the water column, respectively.

Here we prepared a highly efficient and reusable catalyst by a step-by-step postsynthesis modification of UiO-66-NH2 metal–organic frameworks (MOFs) with nitrogen-rich organic ligands and used it as support for the preparation of UiO-66-NH2@cyanuric chloride@2-aminopyrimidine/PdNPs. The catalytic performance’s results of UiO-66-NH2@cyanuric chloride@2-aminopyrimidine/PdNPs, UiO-66-NH2/PdNPs, and UiO-66-NH2@cyanuric chloride/PdNPs indicate high efficiency of the modulation of the microenvironment of the palladium NPs. The addition of N-rich organic ligands through postsynthesis modification caused a unique structure of the final composite in favor of the progress of the C–C coupling reaction. Various techniques, including FT-IR, XRD, SEM, TEM, EDS, and elemental mapping, were used to characterize UiO-66-NH2@cyanuric chloride@2-aminopyrimidine/PdNPs, indicating its successful preparation. Three C–C coupling reactions, including the Suzuki, Heck, and Sonogashira coupling reactions, were promoted using the produced catalyst. As a result of the postsynthesis modification (PSM), the proposed catalyst displays improved catalytic performance. In addition, the suggested catalyst was highly recyclable up to ten times without leaching of PdNPs.

In this study, hybrid aerogels containing carbon nanoparticles (CNP) and multi-walled carbon nanotubes (MWCNT) were synthesized via sol–gel method using resorcinol/formaldehyde precursors through a hydrolysis-condensation reaction mechanism. Porous carbonaceous structures were achieved by freeze-drying of the organic gels followed by controlled carbonization under an inert gas. The samples were characterized by various techniques such as FTIR, BJH, FESEM, CV, and EIS. The specific surface area and total pore volume of the aerogel sample were measured to be as high as 452 m2/g and 0.782 cm3/g, respectively, thus enhancing the electric double-layer formation. Electrochemical tests on the samples showed a large specific capacitance (212 F/g) and an excellent cyclic stability over 3000 cycles. Performance of the synthesized structures was subsequently assessed as electrodes in a capacitive deionization (CDI) process. At the operating conditions of 1.6 V voltage, flow rate of 20 mL/min, and NaCl concentration of 1000 mg/L a promising adsorption capacity around 42.08 mg/g was achieved.

Layered oxide cathode materials are synthesized by performing multiple experiments. Optimizing the structure and morphology of cathode particles requires repeating experiments with different operating parameters, such as pH, ammonia concentration, reaction temperature, and stirring speed. Because numerous tests are necessary to achieve the optimal cathodic structure, significant cost and time are required, which can be reduced by modeling the precipitation process. In this study, we focused on nucleation steps in the reactor to understand various physical phenomena that occur during the coprecipitation synthesis process. Our computational model can predict the stoichiometric ratio of transition metal hydroxide precursors synthesized during the coprecipitation process at different pH values and ammonia concentrations inside the reactor and identify synthesis conditions needed for obtaining a specific stoichiometric ratio of transition metal hydroxide precursors. To confirm modeling results, several coprecipitation synthesis processes were performed. Experimental results were compared with modeling results. By using the model, 2 M ammonia concentration and pH 11.5 were determined to be optimal for the synthesis of NCM811 hydroxide precursors. Experiments performed to confirm modeling results indicated that the hydroxide material synthesized in the mentioned conditions had higher tap density and better electrochemical performance in the battery test. This article is protected by copyright. All rights reserved.

In the present study, after the synthesis of Cu-based metal–organic framework (MOF), to take its advantage in electrode active material of a supercapacitor, Nickel and Vanadium were added to the synthesized MOF through post-synthetic procedures and after calcination at a temperature of 500 °C, two composites of CuO/NiO, and CuO/NiO/Ni3(VO4)2 were achieved to study the effect of Nickel Vanadate on the supercapacitive performance of the CuO/NiO composite. The synthesized active materials were characterized with powder X-ray diffraction analysis, Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, as well as surface area and porosity analyzer. Moreover, to observe the effect of various electrolytes on the electrochemical performance of each composite the cyclic voltammetry and galvanostatic charge–discharge studies were performed in four different environments of Na2SO4 (1 M), NaOH (3 M), KOH (3 M), and LiOH (3 M). The results of CV and GCD tests revealed the pseudocapacitive behavior of the fabricated active material, in which the CuO/NiO/Ni3(VO4)2 electrode yielded the maximum storage capacity at a gravimetric current of 2 A/g with the amount of 37.04 C/g in LiOH (3 M) electrolyte. Moreover, Dunn's calculation revealed that both surface- and diffusion-dominated processes contributed differently to the electrode's overall capacity for charge storage in all electrolytes.

In this research a highly efficient and heterogeneous catalyst of ZSM-5@APTMS@(E)-4-((pyridin-2-ylimino)methyl) benzaldehyde@Cu-NPs was synthesized for upgrading the A3 coupling reaction for the synthesis of propargylamines under mild conditions. Rational tuning of the microenvironment of metallic NPs to improve efficiency and reusability in catalytic performances is of significance for scalable applications. Firstly, ZSM-5 was immobilized with APTMS (3-aminopropyltrimethoxysilane) and further modified with (E)-4-((pyridin-2-ylimino)methyl)benzaldehyde. Subsequently, the amine-activated zeolite@(E)-4-((pyridin-2-ylimino)methyl)benzaldehyde was applied to increase the stabilization of Cu metal nanoparticles. The catalyst was treated with hydrazine to reduce Cu(ii) to Cu(0), which led to active metal sites. The results of catalytic performance in comparison with different parts of catalysis indicate high efficiency due to the stabilization of copper nanoparticles onto the newly synthesized support of MOF modified with nitrogen aromatic groups. The addition of N-rich organic ligand through modification alters the electronic structure of the final composite in favor of the progress of the A3-coupling reaction. Moreover, the proposed catalyst showed no reduction in the catalytic performance up to four cycles, and a minor loss of efficiency occurs after the seventh cycle. In addition, the catalyst was effectively recycled up to 7 times without leaching of Cu-NPs.

Novel composites (MOF-5 and Cu-BDC) based on economically activated carbon have been developed to investigate methane adsorption capacity for ANG applications. The composites were synthesized by adding MOFs precursor in two different weight percent (10% and 40%) to commercial activated carbon under solvothermal conditions (110-120°C). The synthesized adsorbents were characterized by FT-IR, XRD, SEM, EDS, and BET techniques to gather information about their crystallinity, morphology, and specific surface area. A methane uptake measurement system based on the volumetric method was made to obtain methane adsorption capacity on each composite. Then, the amount of methane adsorption for each one was calculated, and the experimental data were compared with different isotherm adsorption models appropriate for gas adsorption, including Langmuir, Freundlich, and Dubinin-Radushkevich. This comparison showed that the best fitting belonged to the Langmuir isotherm model. Also, stability and kinetic studies were done for two MOF-540% @AC and Cu-BDC40% @AC composites. In the kinetics study, experimental data were compared and analyzed in terms of pseudo-first order, pseudo-second order, and intraparticle diffusion models. The kinetics study showed that methane adsorption happens very fast on the synthesized adsorbents. The amount of methane adsorption at 35 bar and room temperature for pure activated carbon was specified as 4.32 mmol/g. The 10% and 40% of Cu-BDC with activated carbon are 5.59 mmol/g and 6.85 mmol/g, respectively. The capacity of MOF-510% @AC and MOF-540% @AC composites were obtained at 5.9 mmol/g and 7.3 mmol/g, respectively. Increasing methane uptake (70%) was obtained by adding 40 wt.% of MOF-5 to commercial activated carbon.

Nowadays, much attention has been paid to reactive composites due to their superior mechanical properties and sintering ability compared to conventional composites. In this study, a comparative evaluation of mechanical and microstructural properties of ZrB2-SiC composites fabricated by in situ reaction of ZrO2 + B4C + SiC (ZBS) and non-reactive sintering of ZrB2-SiC (ZS) powders via the spark plasma sintering (SPS) method is investigated. The SPS process was conducted in a vacuum atmosphere and sintering temperatures of 1900 and 2000 °C for 10 min. XRD and FESEM/EDS analysis were carried out for phase characterization and microstructural studies. Bulk density, microhardness, bending strength, and K1C of the fabricated composites were compared. A high shrinkage of the ZBS sample is observed due to the reaction of raw materials, while the ZS1 and ZS2 samples indicated lower shrinkage. This reaction is confirmed by vacuum changes above 1250 °C due to the formation of B2O3 and CO gases. XRD characterizations showed the complete formation of the ZrB2-SiC composite in the ZBS sample. Microstructural studies revealed complete densification of the ZBS composite, while the presence of porosities is observed in the ZS1 sample. A high relative density of 99.8 ± 0.6%, bending strength of 983 ± 36 MPa, hardness of 23.2 ± 2 GPa, and K1C of 5.18 ± 0.63 MPa.m 0.5 were obtained for the ZBS composite, while lower values of relative density (90.5 ± 0.9%), bending strength (554 ± 28 MPa), hardness (17.3 ± 1 GPa) and K1C (3.92 ± 0.15 MPa.m 0.5) are obtained for ZS1 specimen. Increasing the sintering temperature in the ZS2 sample gave a relative density of 99.9%. But it still had weaker bending strength (703 ± 26 MPa), hardness (18.11 ± 1 GPa), and K1C (4.21 ± 0.23 MPa.m 0.5).

The positive effect of buffers to maintain a sui pH for microorganism growth and increase the electrolyte conductivity in microbial fuel cells (MFCs) encourages more studies on the development of new buffer solutions. The effect of types of biological buffers such as phosphate, tris, succinate, and maleate on power production in dual chamber MFC inoculated by saccharomyces cerevisiae has been examined. Electrochemical impedance spectroscopy has been used for evaluating the performance of the buffered and non‐buffered MFC systems. Considering the important impact of buffer type on the resistance of ion migration within the electrolyte and electron transport resistance of the cell components, the internal resistance of the MFC with different used buffers has been obtained and compared. According to the obtained results, the tris buffer solution showed a positive influence on the power output with a power density of 25.41% higher than phosphate.

Hyaluronic acid (HA) is of immense importance to biomaterials science and biomedical engineering. It is finding applications in diverse areas of bioengineering ranging from scaffolds for disease modelling to tissue culture for reconstruction. This review focuses on recent research on the role of HA as a photo-cross-linked bioink and its importance in combating bone and cartilage-related disease, injury and disorders. Photo chemical modifications and 3D fabrication technologies employed to produce HA-modified materials are analysed to provide a fundamental understanding of the structure–function-property relationships that influence printability, shape fidelity and biological performance both in-vitro and in-vivo. The article concludes with a future vision for HA-based bioinks and their deployment in light-based bioprinting technologies for bone and cartilage repair.

Nanoparticles have a special potential to be used as a co-collector in the flotation process of various minerals. Therefore, in this work, the ability of nano-polystyrene (NP) to facilitate the flotation of Chadormalu iron ore has been investigated. Accordingly, to remove silicon and phosphorus while improving iron content and iron recovery, NP was used as a co-collector in reverse flotation along with dodecylamine cationic and fatty acids anionic collectors. The results showed that NP as a cationic collector with hydrophobic properties is easily adsorbed to quartz anionic particles and by increasing its hydrophobicity, has improved their floating. However, increasing the dose of NP has reduced the flotation of impurities due to the aggregation of NP and the coverage of large areas of mineral particles. The use of gelatinized starch as a depressant in the presence of NP, in addition to reducing the amount of silicon and phosphorus (to 1.1% and 0.052%, respectively), improved the amount of iron and iron recovery (to 68.3% and 89.6%, respectively). The results of this work introduce a new class of special collectors to improve the commercial flotation of iron ore.

Novel bi- and trinuclear palladium(II)-sodium complexes, {[PdL]Na(NO3)(EtOH)} (1) and {[PdL]2Na}Cl (2) based on salophen-type Schiff base N,N'-(1,2-phenylene)-bis(3-methoxysalicylideneimine) (H2L) were synthesized under ambient and sonochemical conditions. Ultrasonication proved to be a more effective method for the rapid synthesis of these bi- and trinuclear complexes under mild conditions. On the basis of the molecular structure of complexes 1 and 2, each palladium atom is placed in the “inner” N2O2 compartment, and the sodium atoms are located in the “outer” O2O’2 compartment of the twofold deprotonated bis-Schiff base ligand. In both complexes, each Pd(II) ion is four coordinated showing square planar geometry, whereas the Na(I) ions in complexes 1 and 2 adopt two different geometries, namely hepta and octa coordination, respectively. In addition, the solventless thermolysis of both complexes at 500 °C was also studied by thermal gravimetric analysis (TGA). EDX and powder XRD data pointed out the presence of highly pure nanoscaled materials. Furthermore, the anticancer and antibacterial activities of bi- and trinuclear complexes were examined towards MCF-7 human breast cancer cell line and evaluated against one gram-negative strain (Escherichia coli ATCC 25922) and one gram-positive strain (Staphylococcus aureus ATCC 6538). The in vitro studies revealed that complex 2 exhibited higher anticancer activity against MCF-7 cell line as well as better antibacterial effect on the examined bacteria strains than complex 1.

Natural mineral clays were extracted from the Syahkalahan mine and used as adsorbent matrices with the aim of removing lead ions (Pb) from drinking water. In this study, the chemical structure, surface morphology, and surface area of prepared clays were characterized using various techniques, including inductively coupled plasma-mass spectrometry, powder X-ray diffraction, field emission scanning electron microscopy (FE-SEM), and Brunauer–Emmett–Teller surface porosity analysis. Characterization results revealed that silica is the dominant chemical component of the clay. FE-SEM images of clay samples confirmed that the average size of clay’s particles is in the nanoscale range. The results for two different clays showed ion removal efficiency of > 92% under the following experimental conditions: clay weight = 1 g, [Pb(II)] =100 ppm, pH = 7, and time = 120 min. Additionally, for the clay samples exhibiting the best removal efficiency, the ion removal efficiency was studied as a function of reaction parameters such as pH, and concentration of both adsorbent and metal ions. To evaluate the adsorption kinetics and mechanism of ion adsorption, kinetic modeling and isotherm models (Langmuir and Freundlich) were performed under the optimized conditions. Based on the fitting analysis, it can be inferred that the adsorption kinetic follows a pseudo-first-order model and the Langmuir isotherm accurately describes the adsorption mechanism of Pb(II) ions on the clays’ surface. These findings further highlight that these inexpensive natural clays can be used as excellent matrices for the adsorption of heavy metal ions in various water treatment systems.

Background Tissue engineering is an emerging technology developed for the therapeutic reconstruction of damaged tissue. Objective In this study, a ceramic/polymer nanocomposite bone tissue engineering scaffold was prepared by coating a tetracalcium phosphate/dicalcium phosphate mixture slurry on a porous 3D chitosan-gelatin construction. Methods The phase composition, structural groups, and morphological aspects of the samples were characterized. Furthermore, the 3D composite scaffold was immersed in simulated body fluid (SBF) solution at 37 ºC for various periods to track its compositional and structural changes. Results Based on the results, the coated layer is composed of needle-like carbonated apatite nanosized crystals with some tetracalcium phosphate/dicalcium phosphate initial materials. The nanocomposite was porous with an average macropore size of about 410 µm. The in vitro tests revealed that the composition of the coated layer tends to be apatite crystals, which are similar to natural bone in terms of chemistry and morphology Conclusion The results suggest that a simple coating of chitosan-gelatin scaffolds using reactive calcium phosphate particles may introduce a novel nanocomposite scaffold with improved mechanical strength, bioactivity, and osteoconductivity.

Application of cost-effective pretreatment of wheat straw is an important stage for massive bioethanol production. A new approach is aimed to enhance the pretreatment of wheat straw by using low-cost ionic liquid [TEA][HSO4] coupled with ultrasound irradiation. The pretreatment was conducted both at room temperature and at 130 °C with a high biomass loading rate of 20% and 20% wt water assisted by ultrasound at 100 W-24 kHz for 15 and 30 min. Wheat straw pretreated at 130 °C for 15 and 30 min had high delignification rates of 67.8% and 74.9%, respectively, and hemicellulose removal rates of 47.0% and 52.2%. Moreover, this pretreatment resulted in producing total reducing sugars of 24.5 and 32.1 mg/mL in enzymatic saccharification, respectively, which corresponds to saccharification yields of 67.7% and 79.8% with commercial cellulase enzyme CelluMax for 72 h. The ethanol generation rates of 38.9 and 42.0 g/L were attained for pretreated samples for 15 and 30 min, equivalent to the yields of 76.1% and 82.2% of the maximum theoretical yield following 48 h of fermentation. This demonstration provided a cheap and promising pretreatment technology in terms of efficiency and shortening the pretreatment time based on applying low-cost ionic liquid and efficient ultrasound pretreatment techniques, which facilitated the feasibility of this approach and could further develop the future of biorefinery.

Different types of wound dressings have been introduced in various forms such as membrane, gel, sponge, and hydrocolloid. Bacterial cellulose (BC) is a natural polymer produced by many bacterial cells. It has received much attention in wound healing due to its attractive and suitable properties including purity, ultrafine network structure, high water-holding capacity, excellent mechanical properties, cytocompatibility, and high crystallinity. In this review, the wound healing process is first described, then the types of wound dressings and their advantages and disadvantages are discussed. Also, BC-based wound dressings and their combination with other materials are investigated for antimicrobial activity.

Due to their structural diversity, superior physiochemical characteristics, and promising electrochemical performance, metal-organic frameworks (MOFs) and layered double hydroxides (LDHs) have garnered substantial interest as potential materials for electrochemical energy storage and conversion. We provided three bimetallic layered double hydroxides (LDH): NiAl-LDH, CoAl-LDH, and ZnAl-LDH from aluminum-fumarate metal-organic frameworks (Al-Fum MOF) as a sacrificial template using a facile solvothermal method in an alkaline environment. Numerous materials containing aluminum are considered one of the best cathode materials for supercapacitors due to their applicability and structural tunability. These as-prepared active materials were sprayed on a nickel foam and used in three- and two-electrode setups. After conducting several electrochemical measurements such as CV and GCD, NiAl-LDH performed as the superior electrode with low charge-transfer resistance and higher capacity of 2.86 Ω and 373 F g⁻¹, respectively. After assembling the asymmetric supercapacitor (ASC) system based on the NiAl-LDH, the maximum energy density of 8.65 Wh kg⁻¹ at a power density of 155.58 W kg⁻¹ was attained at the potential window of 1.5 V with the excellent cycling lifespan (∼ 95% retention) after 10,000 cycles. In this paper, we present a method for modifying a common material and developing it into new materials for future applications in energy storage.

This paper proposes a hierarchical control approach for SuperCapacitor (SC) energy storage and microsources in islanded DC microgrids. It takes into account microsources’ dynamic and steady-state limitations. The proposed approach relies on an architecture presented for the SC’s and microsources’ interfaces with the DC bus. In the proposed architecture, DC microsources interface with the DC bus through buck converters. Moreover, the SC interfaces with the DC bus through the bi-directional buck converter. The instantaneous loads currents are measured and employed in the secondary control to calculate the reference currents for buck converters. In the primary control, we run buck converters as current sources. Moreover, the bi-directional buck converter is run to regulate the DC bus voltage. The proposed approach is generic; meaning that it can be employed for any islanded DC microgrid. Without loss of generality, to prove its effectiveness, we utilized it for a Low Voltage DC (LVDC) microgrid in this paper. Analysis, design, simulations, and experimental verifications are presented for the LVDC microgrid. The experimental results confirm that, by employing the proposed approach, the DC bus voltage deviations from its reference voltage is 5% and it restores in less than 1 sec .

In this research, the samples were exposed to full and partial solution heat treatments and quenched in the air and nitrogen each period. Also, one sample was kept in the liquid nitrogen for 2 h after cooling in the air and isothermal process. In the end, the samples were aged. At every stage, samples were investigated using scanning electron microscope (SEM) and microhardness HV test. The results showed that the rejuvenation heat treatment leads to formation of nanoprecipitates with the cubic morphology in the matrix. The percentage of nanoprecipitates after aging increased by about 87/8%. Keeping in the liquid nitrogen after full solution increased the volume fraction of the small precipitates by about 85%. After partial solution heat treatment, the precipitates became coarse and volume fraction increased to 74%. By increasing the cooling rate, microhardness increased from 620 to 786 microhardness HV after aging. After solutionizing and high rate quench, the microhardness of the blade airfoil decreased to 361 HV, which means a successful solutionizing as the main stage of rejuvenation. During rejuvenation, the size and volume fraction of γ´ precipitates decreased in the solution step and increased by aging. The use of cryogenics and the high rate of quench caused the improvement in the rejuvenation process compared to previous researches. This research can be a start for using this new method of rejuvenation.

Thin-film nanocomposite reverse osmosis (TFN-RO) membranes were fabricated in this study. Titanium silicate-1 (TS-1) was used as an additive during interfacial polymerization. Since nanoparticle dispersion in the membrane matrix is a significant challenge in fabricating high-performance membranes, polyvinyl alcohol/titanium silicate-1 (PVA/TS-1) composite with different PVA polymer dosage was prepared and used in TFN-RO membrane to provide better dispersion of the synthesized TS-1. As a result, the pure water flux increased by 39.5%, and the NaCl rejection improved from 95.03% to 99.1% at the optimum content of 0.1 wt.% (PVA) and 0.1 wt.% (TS-1). The antifouling properties of this membrane for bovine albumin serum (BSA) and humic acid (HA) were enhanced. Characterization of the morphologies of the membranes was investigated using AFM and FESEM. The measurement of water contact angle and zeta potential was accomplished to characterize the surface properties of the membranes. ATR-FTIR was used to study the chemical structure of the membranes. Following the introduction of the PVA/TS-1 composite, the TFN membranes became smoother, thinner, more hydrophilic, and negatively charged. Due to hydroxyl groups and less cross-linked structure of the top layer, water flux was higher. A smoother surface and more negative charges on the top layer also improved fouling resistance.