Environmental and financial concerns have motivated road authorities to limit the utilization of natural resources in road construction, particularly the resources that cannot be renewed. To fulfill ...such requirements, pavement researchers have successfully utilized reclaimed asphalt pavement (RAP) materials as an attractive alternative to their natural counterparts. In practice, rejuvenators are often used to amend the properties of the RAP binder. The addition of the rejuvenator in the mixtures containing RAP materials could completely change the behavior of the mixtures. Such changes in the mechanical responses of the asphalt mixtures are essential aspects of pavements’ lifetime performance and should be considered during the asphalt mix design. Although the self-healing performance of asphalt mixtures prepared by virgin materials is well researched, a few research studies have been carried out to investigate the healing properties of asphalt mixtures prepared by RAP materials. This paper examines the influence of the addition of rice bran oil (RBO) capsules on the self-healing performance and mechanical properties of the asphalt mixtures containing various amounts of RAP: 20% and 40% and control mix containing no RAP material. In general, it was found that the addition of the capsules into the mixtures with RAP materials decreased the resilient modulus and flow number (FN) values. As a consequence of the fact that some part of the rejuvenator inside capsules is released into the mixture during mixing and compaction; moreover, the skeleton structure of capsules is weaker than aggregates, which allows the reduction in the maximum density. Further, the addition of capsules into the asphalt mixture without RAP has increased the fracture energy since the inclusion of capsules would increase the bond between asphalt binder and aggregates. In contrast, encapsulated mixtures containing RAP materials had lower fracture energy values compared with their corresponding mixtures without capsule addition. Furthermore, the results revealed that the addition of RBO capsules to the mixtures with RAP materials increased the healing performance of mixtures due to the fact that the reduced viscosity of aged asphalt binder had increased following the gradual release of the rejuvenator; therefore, the microcracks were closed and prevented further damages.
Metal-organic frameworks (MOFs) are attractive functional materials due to their high surface area, high porosity, and flexible compositions. However, the high precursor cost and complex synthetic ...processes hinder their large-scale applications. Herein, a novel green approach has been developed toward the synthesis of Cu-based MOF by a solvent-free mechano-synthesis method and utilizing consumed polyethylene terephthalate (PET)-derived benzenedicarboxylate (BDC) as the linker. The as-prepared CuBDC and aminated CuBDC (CuBDC-NH2) act as green catalysts for the reduction of deleterious 4-nitrophenol (4-NP) into the value-added 4-aminophenol (4-AP). Compared with CuBDC, CuBDC-NH2 shows increased adsorption capability and reduction efficiency. The mechanism and thermodynamic studies suggest that the adsorption of 4-NP on CuBDC-NH2 is an endothermic, spontaneous, favorable, and physical adsorption process. Furthermore, CuBDC-NH2 can expedite the reduction of 4-NP by participating in an adsorptive catalytic process. With the CuBDC-NH2 catalyst, the catalytic normalized kinetic rate of 4-NP was achieved 11.28 mol/min. mg, outperforming state-of-the-art catalysts, and a complete reduction occur in 5 min for a concentrated effluent (200-ppm 4-NP). The plastic waste-derived MOF-mediated catalytic valorization of organic pollutants demonstrated here opens an avenue for the green recycling/utilization of plastic waste, providing meaningful insights into the sustainable management of organic pollutants in wastewater.
Display omitted
•Modified alkaline hydrolysis extraction of high-quality PET-derived BDC in a novel rotary autoclave•Solvent-free green synthesis of waste PET-derived CuBDC•High 4-NP adsorption capacity of green CuBDC-NH2•Achieving comparative high instantaneous efficiency in the reduction of 4-NP to 4-AP•Meticulous mechanism study of adsorptive catalytic reduction of 4-NP
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Conventional fossil-based energy sources have numerous environmental demerits; sustainable and renewable sources are attracting the undivided attention of researchers owing to their valuable physical ...and chemical features. Several industrial-scale technologies are employing hydrogen as a green energy source as the most preferential source. Not only is hydrogen a potent energy carrier but also it is not detrimental to the environment. Among many other hydrogen production processes, steam reforming of methanol (SRM) is deemed a practical method due to its low energy consumption. Cu, Ni, noble metals, etc., are the salient catalysts in SRM. Many researchers have conducted thorough studies incorporating improvement of the catalysts’ activity, mechanism predictions, and the impacts of operational parameters and reformers. This review concentrates on the SRM catalysts, supports, promoters, and the effect of the operational parameters on the process efficiency and H2 production yield. In this regard, the methanol conversion, H2 and CO selectivity, and operating parameters are notably contingent on the surface characterization and chemistry of the catalysts. Herein, Cu-, Ni-, and noble metal-based catalysts on various metal oxide supports, such as Al2O3 and ZnO, are assessed meticulously in the SRM process from the standpoint of mechanism and catalyst characterization. Most of the peer-reviewed studies had encountered agglomeration, metal particle sintering at high temperatures, coke formation, and deactivation of catalysts as the prevalent barriers. Hence, the novel methods of conquering the above-mentioned obstacles are evaluated in this review. Employment of diverse synthetic methods, bimetallic catalysts, distinct catalyst promoters, and unconventional supports, such as metal–organic frameworks, carbon nanotubes, and zeolites, are the salient routes to overcome the metal dispersion and thermal stability issues. In addition, the influence of operational parameters (temperature of the process, steam/carbon ratio, and feed flow rate) has been weighed painstakingly, along with introducing the research gap and future perspectives in the territory of SRM catalysts.
Natural pyrite catalysts were utilized in fluidized bed reactor for dye degradation in presence of hydrogen peroxide, which is famous to heterogeneous Fenton reaction. This process plays an important ...role in wastewater treatment processes and it is more effective when occurs in this kind of reactors. A novel kinetic model for Acid yellow 36 (AY36) degradation by heterogeneous Fenton process, in a fluidized bed reactor has been developed. By evaluating dissolved oxygen (DO) concentration in effluent during the process, a new parameter named effective reaction time is introduced, which could describe the relation of DO concentration and dye degradation, so the prediction of DO concentration by the model is of great importance toward the understanding of process performance. Neglecting mass transfer phenomenon from kinetic models eventuated in incorrect estimation, consequently, in this model, both reaction and mass transfer mechanism have been considered, which forecast the changes in effective factors like pH, DO concentration and dye removal efficiency simultaneously. The model results adequately coincide with the experimental results, which declare the validity of the modified kinetic model.
Display omitted
•A novel kinetic model for dye degradation by heterogeneous Fenton in a fluidized bed reactor.•Mass transfer is considered in the model.•A new parameter named effective reaction time is introduced.•Effective reaction time could describe the relation of dissolved oxygen concentration and dye degradation.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Heterogeneous Fenton process is a kind of advanced oxidation processes (AOPs) that is significant for wastewater treatment. In the first part of this study, acid yellow 36 (AY36) degradation process ...has occurred in two kinds of reactors: fluidized-bed and stirred-tank reactors. Performances of these two semi-pilot reactors are compared by evaluating the removal ratio of the dye and pH changes during the process. Pyrite has been used as a heterogeneous catalyst. For obtaining the characteristics of pyrite, XRD, SEM, and FT-IR analysis have been carried out. In the second part of this study, a modified computational fluid dynamics (CFD) method has been utilized to solve the momentum and mass balances for heterogeneous Fenton process in both reactors. In AOPs, free radicals are reactive and have a short lifetime, so that turbulence mixing would be a limiting factor for the reactions that radicals are involved. By introducing a new parameter, named turbulence mixing rate, as a reaction rate for reactive species like hydroxyl radicals, the results of removal ratio and pH changes during the process showed a good agreement between the experiments and the CFD simulations, compared with not including the mixing rate in the CFD simulations (conventional kinetic modeling). In addition, the results revealed the high performance of the fluidized-bed reactor for this process in both experiments and CFD simulation.
Display omitted
•Fluidized-bed reactor shows better performance in contrary with stirred-tank reactor.•Turbulence mixing rate is introduced for reactive species in this process as a new parameter for CFD model.•Modified CFD model predicts pH changes and dye removal ratio simultaneously for both reactors.•Modified CFD model yield more agreement with the experiments in compared with conventional kinetic modeling.•Models are in transient state and some results are animated.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The catalytic activity of pure metal nanoparticles is always limited by aggregation during the reaction. Therefore, promising candidates such as metal-organic frameworks possess benefits due to their ...3D porous structures, high stability, and high specific surface area. In this study, effective and reusable catalysts based on M-BDC metal-organic frameworks were synthesized utilizing five different coordinating metal ions (M = Ag, Co, Cr, Mn, and Zr) as metal nodes and 1-4-benzene dicarboxylic acid (BDC) as an organic linker and used in catalytic reduction of 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP) for the first time. The as-prepared catalysts were characterized using SEM, EDX, XRD, and FTIR techniques. Based on catalytic performance, Co-BDC showed the best catalytic efficiency compared to the other M-BDC MOF catalysts with a conversion yield of about 99.25 in 2 min. All of the catalysts could catalyze the complete reduction of 4-NP to 4-AP at different reaction times (2–10); however, Mn-BDC could not finish the catalytic reduction reaction even after 20 min. The two more efficient catalysts including Co-BDC and Cr-BDC demonstrated high stability and reusability (more than 85% catalytic efficiency) even after 5 cycles.
•Five different M-BDC (M = Ag, Co, Cr, Mn, and Zr) were synthesized successfully.•M-BDCs’ performance in catalytic reduction of 4-Nitrophenol to 4-Aminophenol was evaluated and compared.•Co-BDC showed the best catalytic performance among the other catalysts with 99.25% in 2 min.•Prepared catalysts demonstrated acceptable stability and reusability.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A novel environmentally friendly approach was developed to synthesize Cr-BDC@ɣ-Al2O3 granular adsorbents for the purpose of removing mono-ethylene glycol (MEG) as an organic pollutant. The synthesis ...method employed ethanol and water as greener alternatives to dimethylformamide (DMF). Although the granular form of the adsorbent exhibited slightly lower performance compared to the powdered form, it demonstrated superior suitability for separation, regeneration, and industrial applications, such as packed-bed systems. To investigate the influential parameters, the response surface methodology (RSM) was applied, revealing that variations in pH had an insignificant effect on the efficiency of adsorption. The maximum adsorption capacity of 124.45 mg/g was achieved at the highest concentration of the pollutant, attributed to the abundance of pollutant molecules. Based on the RSM results, the optimal conditions for MEG removal were determined as pH 7, a pollutant concentration of 500 ppm, and an adsorbent dosage of 2 g/L. The adsorption kinetics followed the pseudo-quadratic model, with the majority of adsorption occurring within the initial 70 minutes. Thermodynamic studies confirmed the spontaneous and exothermic nature of the adsorption process. The experimental data fitting exhibited good agreement with both the Langmuir and Dubinin-Radushkevich (D-R) isotherms, indicating predominant physisorption and a maximum Langmuir adsorbent capacity of 166.667 mg/g. Additionally, the granular adsorbent demonstrated excellent regeneration capability and remarkable stability even after six consecutive cycles. This study highlights the potential of Cr-BDC@ɣ-Al2O3 granular adsorbents as effective and environmentally friendly materials for the removal of organic pollutants from aqueous systems.
Display omitted
•Green synthesis of Cr-BDC@ɣ-Al2O3 using water and ethanol, replacing DMF as a solvent.•Comparison and optimization of green and conventional solvothermal synthesis methods.•Evaluation of granular and powder forms of adsorbents in MEG removal.•RSM method for optimal operating conditions, achieving a maximum adsorption capacity of 124 mg/g.•Excellent regeneration and stability of the granular adsorbent even after 6 cycles.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pyrolytic coke is formed in olefin plants of petrochemical complexes that is considered as a detrimental waste material. However, it could be used as a suitable carbon source for value-added ...activated carbon production due to its high carbon and low sulfur content. The aim of this is to convert Pyrolytic coke into activated carbon by KOH activation and cold oxygen plasma treatment as the chemical and physical treatment methods, respectively. First, effective parameters of plasma modification such as vacuum pressure and retention time as well as effective parameters of chemical activation such as temperature, activation time and weight ratio of KOH to the coke was optimized by the adsorption performance of Acid Yellow 17 dye (AY17). In the second step, the novel plasma treated activated pyrolytic coke was introduced at the optimum conditions. Vacuum of 0.2 mbar and residence time of 15 min were determined as optimal plasma modification conditions with almost 40 % AY17 removal efficiency. For chemical activation, temperature of 825 °C, activation time of 1 h and KOH to coke ratio of 1:2 were obtained as the optimal conditions. Optimum waste-base adsorbent's characteristics were investigated by SEM, BET, XRD, XRF, FTIR, CHNS and AFM analysis. Surface area of plasma treated activated pyrolytic coke (PTAPC) was reached up to 102.4 m2/g. Isotherm model and adsorption kinetics showed that this adsorbent follows the Langmuir isotherm with a maximum adsorption capacity of 48.52 mg/g and the pseudo second-order kinetic model. Adsorption at acidic pH, especially at pH = 3, has the best results. The main adsorption mechanism at pHs below zero potential is electrostatic interaction between the dye sulfonate anions and oxygenated groups such as hydroxyl.
Display omitted
•Pyrolytic coke as a petrochemical waste can be turn into value-added materials.•Pyrolytic coke inherits >90 % carbon with low sulfur content.•Plasma treatment before chemical activation increases adsorption capacity.•Plasma treated activated pyrolytic coke can be used as a novel dye adsorbent.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Not only is water an essential source for the existence of humans but also it is a necessity for creatures' life. Reutilizing wastewater is a salient way to conquer this rigor; many physical and ...chemical methods have been developed to treat wastewater, one of which is the advanced oxidation process (AOP). In this study, a heterogeneous Fenton reaction was employed to degrade a non-biodegradable organic contaminant (Direct Blue 71) from synthetic seawater. An unprecedented approach and a novel self-created autoclave were employed to synthesize granulated Fe3O4/Cellulose nanocomposites, which were applied in AOPs as catalysts. Characterization of prepared nanocomposites was investigated by various methods confirming that cellulose is uniformly covered by Fe3O4 nanoparticles. The AOP was carried out in two different kinds of batch and fluidized bed reactors. The impacts of three effectual parameters on the dye removal were weighed using response surface methodology (RSM). The obtained results for both systems demonstrated that exploiting 3.1 g/L catalysts besides the presence of 12.95 mM H2O2 could remove 33.12 mg/L dye entirely. In comparison to the batch reactor, only when the process was conducted in a fluidized bed reactor, did the elimination efficiency increase dramatically. Fluidization results indicated a significant enhancement in dye removal efficiency and a sensitive decrement in the degradation process time. The experimental results were in good agreement with the pseudo-first-order kinetic model and the fluidized bed reactor had a greater K value. The synthesized catalysts were biodegradable and they had an acceptable performance up to 6 cycles after each regeneration process.
Display omitted
•New method for synthesis of granulated Fe3O4/Cellulose nanocomposite.•Utilizing a novel and self-created rotary autoclave for synthesis.•Conducting the Azo dye degradation process in two various reactors.•Optimizing the degradation process by RSM.•High stability of synthetic catalysts in the heterogeneous Fenton reaction.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A Cu/Cr-BDC@γ-Al2O3 granular bimetal-organic framework was synthesized for the first time, and its performance in adsorption of thiophene from isooctane was investigated. XRD, BET, FT-IR, SEM, and ...EDX analysis confirmed the successful synthesis of the adsorbent. The adsorption performances of Cr-BDC, Cu-BDC, and Cu/Cr-BDC were compared, and the bimetallic adsorbent had a better performance due to the synergetic effects of the simultaneous presence of metals. Furthermore, the granular adsorbent had a better performance due to the prevention of the particle’s agglomeration. The highest adsorption percentage and adsorbent capacity were 84% and 55 mg/g, respectively. Experimental data fitted with the pseudo-second-order kinetic model as well as the Langmuir and D–R isotherm models indicated that the adsorption was monolayer and chemisorption was the dominating mechanism. The adsorbents were regenerative up to 5 times. Adsorption was due to the weak bonding of lone pair electrons on sulfur atoms of thiophene and empty orbitals of metals.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
