Reaction Conditions Temperature Research Articles

Investigation on preparation and properties of gel type 188W/188Re generator

As one of the most important integrated nuclides for diagnosis and treatment in recent years, rhenium-188 (188Re) has a broad scope in the clinical application. Due to the specific properties of such radionuclide, it was mainly provided by the chromatographic 188W-188Re generators. There is no doubt that the application of 188Re in the treatment of various diseases depended on the development of 188W-188Re generator. Considering the high standards of such technology on radioactive activity of 188W and impurity content, a 188W-188Re generator filled with the zirconium tungstate gel has been prepared in this work. The effects of molar ratio of chemical agents, pH, reaction temperature, drying methods, rinsing methods and other conditions on the synthesis of gel particles have been studied. Furthermore, a variety of characterization techniques were used to observe the macro-/micro-morphology and chemical structure of gel particles. It can be concluded that vacuum freeze-dried method could significantly increase the specific surface area, pore size and tungsten content of gel particle. In order to decrease the content of 188W in the elute, a handful of acidic alumina was filled in the bottom of our 188W-188Re generator, an elution and purification integrated-generator was formed. During the first five processes, the nuclear purity of 188Re solution was above 99.99%, the radiochemical purity was approximately 99.5%, the pH value was 5.0–7.0 and the average elution efficiency reached up to 82.7%. In addition, the leakage rate of 188W was low as 1.60 × 10−6, and the peak of elute curve was located at 2 mL without the trailing phenomenon. This work lays a solid foundation for the domestic demand of daughter nuclide 188Re, further makes an outstanding contribution to the application of the radiation therapy technology and the protection of people's health.

Dephosphorisation behaviour of blast oxygen furnace (BOF) slag due to carbothermal reduction

ABSTRACT The thermodynamic analysis of converter slag by carbothermal reduction was carried out. The laboratory tests of converter slag by carbothermal reduction dephosphorisation were carried out in molybdenum disilicide high-temperature resistance furnace and 500 kg top bottom combined blowing multi-functional test furnace respectively. The results show that the reaction temperature and kinetic conditions have a great influence on the dephosphorisation rate. In the top and bottom combined blowing multi-functional test furnace, coke powder is used as both reducing agent and heating agent. The exothermic reaction between coke powder and oxygen can ensure that the dephosphorisation reaction can be carried out at a higher temperature. At the same time, the good stirring of topblowing oxygen on the slag layer is conducive to further improve the dephosphorisation reaction speed.

Selective hydrogenation of 5‐hydroxymethylfurfural to 5‐hydroxymethyltetrahydrofurfural over heterogeneous Pd catalyst under mild conditions

5‐Hydroxymethylfurfural (5‐HMF) derived from lignocellulose represents an important platform molecule that could be employed in the selective hydrogenation of the furan ring to prepare 5‑hydroxymethyltetrahydrofurfural (HMTHF). However, the reported catalytic systems for the synthesis of HMTHF using 5‐HMF still require additional hydrogen pressure. In this study, the Pd/ZrO2 catalyst with uniformly dispersed Pd nanoparticles was prepared via a simple impregnation reduction process. This catalyst exhibited excellent catalytic activity and selectivity for the hydrogenation of 5‐HMF to HMTHF. High HMTHF yield up to 92.3% was produced under mild reaction conditions of ambient hydrogen pressure and room temperature in methanol solvent. This result was superior to the most catalytic systems that had been reported so far. The mechanism study revealed that the active hydrogen species on the surface of the Pd nanoparticles and the reaction solvent in this study were the pivotal factors influencing the hydrogenation of furan rings in 5‐HMF.

Room Temperature Regioselective Debenzylative Cycloetherification Reaction.

A regio- and stereoselective debenzylative cycloetherification (DBCE) reaction of protected hexoses to form stereodefined hydroxylated tetrahydrofurans of synthetic utility has been investigated under very mild room temperature reaction conditions. This study revealed the potential application of the DBCE reaction of simple, abundant starting materials to access stereochemically rich tetrahydrofuran compounds under mild reaction conditions.

Optimisation of Catalytic Oxidation Conditions for the 2‐Keto‐L‐Gulonic Acid Production Using Response Surface Methodology

AbstractL‐Ascorbic acid, also known as vitamin C, is a very important antioxidant ingredient situated many usage areas in different industries. 2‐keto‐L‐gulonic acid (2‐KLG) is the main precursor component of L‐ascorbic acid production and it can be produced from L‐sorbose via microbial fermentation or chemical (catalytic) oxidation. While some special strains are used in microbial fermentation, it is benefitted from some catalysts in chemical oxidation. Herein, it was aimed to determine the optimum reaction temperature, pH, and time conditions to produce maximum 2‐KLG compound with the catalytic oxidation of L‐sorbose in the presence of Pt/Al2O3 catalyst with response surface methodology approach. For this aim, the reaction temperature, pH, and time used as variable factors. The limit values of variable factors were applied as 40–60 °C for the temperature, 7.00–9.00 for the pH value, and 3–9 h for the time. The analyses results demonstrated that the increasing temperature and time negatively effected the conversion of L‐sorbose into the 2‐KLG. The optimum conditions of variable factors were determined as 41.30 °C for the temperature, 8.23 for the pH, and 3.25 h for the reaction time by the central composite design. Under these optimum conditions, L‐sorbose was converted into 2‐KLG with an average yield of 43.70 %.

Obtaining high H2-rich syngas yield and carbon conversion efficiency from biomass gasification: From characterization to process optimization using machine learning with experimental validation

Gasification, among the other thermochemical processes, stands as a promising method for sustainable waste management while generating valuable H2-rich syngas. In the last few years, there has been a significant surge in the adoption of machine learning (ML) techniques for modelling biomass as well as gasification and pyrolysis of waste. The present study unveiled the supremacy of Gaussian Process Regression (GPR) algorithm as compared to other ML models, in predicting syngas yield [Ysyn (Nm3/kg of biomass)] and carbon conversion efficiency[ηCarbon(%)] respectively, with a high prediction accuracy of R2 > 0.9 in both the cases. The necessary datasets were collected from experimental trials, at reaction conditions of temperature (T): 550–1000 °C, air flow rate (AFR): 0.02–0.04 L/min, and reaction time of 2 h, in a two-stage fixed bed reactor, which were identified on the Basis of thermodynamic as well as stoichiometric analysis. Additionally, the models were employed in Bayesian optimization within a weighted multi-objective framework to obtain the optimal operational parameters, focusing on maximizing both yield and conversion simultaneously. Finally, this result was validated experimentally to check the sanctity of the data-driven optimization.

Design of Experiment Is All You Need: Utilizing AI for High-Entropy Alloy Water Splitting Catalyst

High-entropy alloy (HEA) is a new group of material that have excited both fields of electrochemistry and computational chemistry, based on its intriguing concept and outstanding catalytic activity. Nevertheless, there exists a clear limitation to the 'trial-and-error' based research: its compositional space is too large. Therefore, AI-based high-throughput research is considered as an efficient way to optimize the composition of HEA electrocatalysts. To fully utilize AI's potential, the quality of data and rational Design of Experiment (DoE) is of importance. In this regard, we have 1) developed an automated one-step synthesis method of HEA with liquid handler and 2) made machine learning model with Gaussian process (GP) regression to minimize the overpotential (fig. 1a).DoE helps developing a new experiment by categorizing the variables and steps that are necessary. First step of DoE is to start with listing the variables. For the one-step synthesis of HEAs, independent variable was the composition of each elements, where the control variables were:A. Solvent (Amine/ethanol)B. Addition of CNT (O/X)C. Reaction temperature (high/low)D. Reaction time (long/short)E. Concentration of solution (5 mM / 10 mM)Each of control variables have two options and the selection is represented by writing an alphabet. For example, if amine (A) and high reaction temperature (C) condition was selected while the second option is used for the rest, it is written as AC. Based on confounding method theory, by conducting AC experiment, we also get information about BDE experiment by assuming a negative correlation to each other. It is written as: AC = -BDE. Similarly, an equivalent combinatorial list can be made for every possible combination (=25) , while the number of experiment is reduced from 32 to 16. Among these combinations, ABCE was found to be optimal synthesis condition (fig.1b).Afterward, we searched the optimal composition of HEAs, starting with grid searching the six-dimensional compositional field. MnFeCoNiCuMoPdPt - octonary alloy was the targeted alloy where the compositions of noble metal were fixed. Binomial distribution design was used to make the distance between neighboring points in 6-dimension compositional space equal (fig. 1c-d). 8C3 = 56 combinations were selected and consequently, the corresponding amounts of precursor solutions were transferred to 56 heat-inert vials and underwent heat treatment of 200 °C. Overpotential of 56 samples were measured and simple GP regression model was constructed based on these datasets.GP regression is composed of two parts: exploration and exploitation. During exploration, the optimal combination is recommended by searching the point that has the largest deviation. Interestingly, by comparing the Shapley Additive explanations (SHAP) value of each elements, it is clearly proved that Cu was harmful and Ni was beneficial to water splitting performance. Thus, Cu was screened out during the end of the exploration step. After finishing exploration, the next combination was recommended by searching near the point with least overpotential (exploitation step). By using GP regression, the optimal composition among HEAs was discovered in less than 200 experiments. It showed the overpotential less than 30mV for HER and less than 250mV for OER, making the overall water-splitting potential less than 1.5 V. In summary, a GP regression model showed synergistic effect with DoE, and HEA with the optimal composition showed an outstanding water splitting performance, reducing overall overpotential by 50% compared to the first step. Figure 1

In-situ preparation of MnFeCoNiCu/C for the sustainable co-production of bio-jet fuel and green diesel under solvent-free and low hydrogen pressure conditions

The conversion of non-edible oils such as fatty acid methyl esters (FAME) into green and renewable liquid fuels align with the current trend of sustainable development. However, traditional processes often involve multi-step process to prepare catalyst and require high-pressure hydrogen. This study reports a strategy for the in-situ preparation of MnFeCoNiCu/C catalyst, enabling the one-step conversion of FAME into bio-jet fuels and hydrocarbon-based diesel under solvent-free and low-pressure conditions. The effect of active metal loading, reaction temperature, hydrogen pressure, and ZSM-5 zeolite addition on the catalytic performance was investigated. Under the conditions of reaction temperature 350 ℃ and hydrogen pressure 2 MPa, the conversion rate of FAME reaches 100 %, and the selectivity of bio-jet fuel and green diesel is 48.35 % and 51.05 %, respectively. A small number of olefins, cycloalkanes, and aromatics can also be detected in the products. After the 4 cycles of AC-15 catalyst, the selectivity of bio-jet fuel and diesel are 40.09 % and 39.81 %, respectively. The above research work provides a mild and efficient method for the preparation of renewable bio-jet fuel and green diesel.

Decorated gelatin polymer onto copper aluminum layered double hydroxides for superior removal of Congo red: Optimization and adsorption evaluation of kinetics, isotherms, and thermodynamics

Azo-dyes are highly soluble in water and well documented by their toxic and nonbiodegradable characters and the removal of such dye pollutants from wastewater is aimed to control environmental pollution. Therefore, the current study is designed and executed to efficiently remove Congo Red dye pollutant (CRDP) as an example of azo-dye coloring materials by using a newly synthesized nanobiosorbent. The aimed Cu/Al-LDHs@Gltn nanobiosorbent was prepared by the direct combination and binding of gelatin as a sustainable biopolymeric material with copper aluminum layered double hydroxides (Cu/Al-LDHs) by using a green microwave synthesis approach. Several characterization techniques were applied to confirm the morphology and structure of Cu/Al-LDHs@Gltn. The particle size range was identified by using the SEM analysis from 16.54 nm to 30.68 nm and the EDX investigation confirmed the elemental existence of C (25.1%), O (41.9%), and N (13.5%), Al (3.2%), Cu (11.9%) and Cl (4.4%) elements. The FT-IR analysis referred to the incorporation of several surface functionalizations as –OH, COOH, metal-O and others, while the BET-surface area configuration was detected (41.35 m2 g−1). Zero-charge point of Cu/Al-LDHs@Gltn was also measured to provide (pHzpc = 6.0). The significant controlling parameters were testified to optimize the pollutant adsorption onto the aimed Cu/Al-LDHs@Gltn via batch removal experiments by using 5-15 mg/L CRDP concentrations. The optimum pH (2.0), reaction duration (35 min), dosage (15 mg) and reaction temperature (25°C) conditions were concluded. Several related models to adsorption isotherm and kinetic studies were explored. The thermodynamic parameters additionally estimated the spontaneity and the exothermal adsorptive reaction of CRDP onto Cu/Al-LDHs@Gltn. This was confirmed to afford high stability and sustainability providing successive efficiency up to 94.6%, 84.1% and 78.8% (1st cycle) and yielded 83.3%, 70.1% and 64.5% (3rd cycle) upon testifying 5, 10 and 15 mg/L CRDP concentrations, correspondingly. Cu/Al-LDHs@Gltn was finally characterized by excellent CRDP removal efficiency up to 92.1-95.1% (5 mg/L CRDP), 91.9-92.3% (10 mg/L CRDP) and 90.4-91.7% (15 mg/L CRDP) from drinking, sea and wastewaters, correspondingly.

Ultrasound-assisted synthesis of novel undecylenic estolides: Modeling and Tribological characterization

Abstract To overcome the issues related to low-temperature characteristics and thermal degradation of fatty acid based lubricant base stocks, chemical modification is essential. To mitigate these shortcomings, considering unsaturated undecylenic acid, the formation of estolides is one of the best transformations considering application in lubricants. Ultrasonic-assisted sulfuric acid-catalyzed synthesis of estolides of undecylenic was modeled using response surface methodology (RSM) and subsequently validated using artificial neural network (ANN) for known and unknown input variables. At optimal reaction conditions of reaction temperature of 56°C, catalyst loading of 0.63 mole-equivalent, and reaction time of 1.61 hours, estolides with estolide number (EN) of 2.58, extraordinary low pour point (PP) of −52°C and better resistance to thermal degradation was obtained. The thermal degradation was evaluated using thermogravimetric analysis (TGA) to find improved resistance toward degradation due to the formation of estolides. Further, tribological properties like wear characteristics, load carrying capacity, and oxidative stability were studied for 5% blends in SN 70 base oil. The anti-wear ability of the estolides was found to be superior to undecylenic acid, with a lower coefficient of friction, scar diameter, depth, and volume. The blend containing estolide was found to have load carrying capacity as high as 800 kgf. Moreover, owing to the double bond migration during the reaction, the oxidative stability of estolides was found to be inferior to the terminally unsaturated undecylenic acid.

Experimental study of synthesis of N-2-Hydroxypropyltrimethylammonium chloride chitosan and carboxymethyl chitosan nanoparticles by ultrasonic microreactor

Abstract To overcome the technical limitations of current batch reactors for synthesizing N-2-HACC/CMCS NPs, an ultrasonic microreactor was designed and fabricated to continuously prepare N-2-HACC/CMCS NPs, which were characterized by SEM, laser particle sizing instrument, and FTIR. The findings indicate that the granular size of the NPs can be precisely regulated by changing the conditions of reaction temperature, ultrasonic power, reactant flux ratio, and reactant concentration. Compared with the batch reactor, ultrasonic microreactors can continuously prepare NPs with smaller and more uniform particle sizes.

Ultrasonic enhanced liquid-liquid interfacial reaction for improving the synthesis of Iron-doped carbon dots (Fe-CDs) for achieving superior photocatalytic performance

The precise and controllable preparation of carbon nanomaterials under mild conditions poses a great challenge, especially for metal-catalysed multiphase preparation. This work proposes an efficient method that utilizing high-density ultrasound to enhance the liquid-liquid interfacial reaction system. Iron-doped carbon dots (Fe-CDs) are successfully synthesized in such a normal temperature and atmospheric-pressure reaction condition. It is shown that transient cavitation provides a high-temperature and high-pressure microenvironment for the preparation of Fe-CDs. Moreover, the size of the reactant droplets is reduced from 200.0 ± 17.3 μm to 8.1 ± 2.9 μm owing to the acoustic flow and cavitation effects, which increases the specific surface area of the two reacting phases and improves the mass transfer coefficient by more than 252.0 %. As a result, the yield increases by more than an order of magnitude (from 0.7 ± 0.1 % to 11.9 ± 0.2 %) and the Fe doping rate reaches 20.9 %. The photocatalytic oxidation conversion of 1,4-Dihydropyridine (1,4-DHP) using the obtained Fe-CDs is as high as 98.2 %. This research gives a new approach for the efficient and safe production of Fe-CDs, which is promising for industrial applications.

Engineering stable active Cu0-Cuσ+ sites via in situ surface reconstruction over Cu/CeO2 catalyst for the hydrogenation of carbon-oxygen bonds

Cu/CeO2 catalysts have been wildly used for the hydrogenation of carbon-oxygen bonds reactions due to their excellent catalytic performance. It is widely accepted that the Cu0-Cuσ+ interface could be the primary active sites during the reaction, but how to form and maintain highly dispersed such species remains challenging under the reaction conditions of high temperature and H2 partial pressure. In this work, we proposed an effective strategy to construct stable Cu0-Cuσ+ interface sites over the Cu/CeO2 catalysts by in situ N2O-involved oxidation treatment. It was evidenced that the sequential oxidation-reduction by N2O and H2 broke the grain boundaries of Cu nanoparticles and therefore facilitated the formation of the active Cu0-Cuσ+ sites, leading to an enhanced activity. However, a rapid deactivation was observed after this temporary enhancement due to the aggregation of copper species. We further introduced some additional cerium species during catalyst preparation. The 16Cu/CeO2-1Ce catalyst prepared by post-impregnation of 1 wt% cerium achieved a stable performance of 90.6% MA conversion after the N2O-involved oxidation treatment, which was much higher than that of 26.2% over the 16Cu/CeO2 catalyst. It was demonstrated that the strong interaction between the formed CeO2 and reconstructed Cu species prevented the metal sintering and increased the fraction of the Cu0-Cuσ+ sites. This method that combined in situ N2O-involved oxidation treatment and cerium modification may offer potential in engineering stable active sites for high-performance catalysts in the hydrogenation of carbon-oxygen bonds.

Simultaneous removal of perfluorooctanoic acid and thiocyanate by modified activated carbon fiber/persulfate system

In this study, NaOH-modified activated carbon fiber (NaOH-ACF) was used as a catalyst to activate persulfate (PS) for the removal of perfluorooctanoic acid (PFOA) and thiocyanate (SCN−) from wastewater. The effects of the crucial parameters in the NaOH-ACF/PS process, including NaOH-ACF dosage, PS concentration and initial pH, were investigated and optimized using response surface methodology. The experimental results indicated showed that under the optimal reaction conditions of NaOH-ACF dosage (0.40 g/L), PS concentration (2.0 mmol/L), pH (3.0), and temperature (25 °C), the removal efficiencies for PFOA and SCN− reached 93.63 % and 95.17 %, respectively, within 60 min of reaction. When PFOA and SCN− coexisted in the reaction system, it was observed that PFOA had minimal effect on the removal of SCN−, while SCN− actually enhanced the removal of PFOA. Free radical identification experiments demonstrated that the NaOH-ACF/PS system generated free radicals (O2−, SO4−, OH) and non-free radicals (1O2), which cooperatively facilitated the degradation of PFOA and SCN−. Furthermore, Liquid Chromatograph-Mass Spectrometer (LC-MS) analysis results have been used to speculate on the possible degradation pathways and intermediates of PFOA. The material characterization results indicated that NaOH-ACF possesses abundant surface functional groups with excellent adsorption and catalytic properties. Thus, the NaOH-ACF-activated PS advanced oxidation process offered a promising approach for the simultaneous removal of Perfluorinated compounds and thiocyanates.

Highly active and stable Ni@SiO2 catalyst for ammonia decomposition

Ammonia is considered as a potential hydrogen carrier as its high hydrogen content. Hydrogen release still presents challenges due to the lack of efficient catalyst. In this work, we report a Ni@SiO2 catalyst prepared through a sol–gel method, which displays satisfied catalytic activity and remarkable long-term stability. The origination of activity and stability has been investigated carefully by various characterizations. The strong interaction between nickel species and silica species is responsible for the excellent performance via generating small nickel particle and hindering the sintering of nickel during the high temperature reaction condition. This study offers novel insights into the design and preparation of highly efficient catalysts for ammonia decomposition to produce hydrogen.

Synthesis of Boron-Containing Nucleoside Analogs.

Over the last century, nucleoside-based therapeutics have demonstrated remarkable effectiveness in the treatment of a wide variety of diseases from cancer to HIV. In addition, boron-containing drugs have recently emerged as an exciting and fruitful avenue for medicinal therapies. However, borononucleosides have largely been unexplored in the context of medicinal applications. Herein, we report the synthesis, isolation, and characterization of two novel boron-containing nucleoside compound libraries which may find utility as therapeutic agents. Our synthetic strategy employs efficient one-step substitution reactions between a diverse variety of nucleoside scaffolds and an assortment of n-alkyl potassium trifluoroborate-containing electrophiles. We demonstrated that these alkylation reactions are compatible with cyclic and acyclic nucleoside substrates, as well as increasing alkyl chain lengths. Furthermore, regioselective control of product formation can be readily achieved through manipulation of base identity and reaction temperature conditions.

Surface functionalization of synthesized sodium alginate from brown algae for maximizing the yield of re-refined used lubricating oil using extraction-flocculation–an environment-friendly approach

This study aims at efficient, economically feasible, and environmentally friendly regeneration of waste lubricant by surface-functionalized bio flocculant via extractive-flocculative technique for maximization of yield. Further, optimization has also been escalated for designing the optimal process parameters (such as reaction time, solvent to waste oil ratio, and bio-flocculant concentration) for enhancing the quality and cost effectiveness of the regenerated product. FTIR, SEM, and TGA analysis were used to characterize the synthesized bio-flocculant. GC-MS, FTIR, and NMR analysis were used to characterize the chemical composition, chemical nature, and functional group of virgin, used, and re-refined lubricant. Experimental findings showed that a grafting efficacy of 76% can be achieved with optimal conditions of reaction temperature of 70 °C, irradiation time of 6 min, 2.5 wt. % monomer concentration and 800 W microwave radiation. Maximum yield of 94% can be obtained with optimal process constraints such as reaction time of 60 min, refining temperature of 80 °C, the ratio of solvent and waste oil of 3:1 g/g and 1 g/kg of solvent flocculant dosage, grafting % of 76. Fuel characterization studies reveal that the fuel characteristics of re-refined lubricant are analogous to those of fresh oil.

Catalytic degradation of antibiotic sludge to produce formic acid by acidified red mud

As complex and difficult-to-degrade persistent organic pollutants (POPs), antibiotics have caous damage to the ecological enused serivironment. Because of the difficult degradation of antibiotics, sewage and sludge discharged by hospitals and pharmaceutical enterprises often contain a large number of antibiotic residues. Therefore, the harmless and resourceful treatment of antibiotic sludge is very meaningful. In this paper, amoxicillin was selected as a model compound for antibiotic sludge. Acidified red mud (ARM) was used to degrade antibiotic sludge and produce hydrogen energy carrier formic acid in catalytic wet peroxidation system (CWPO). Based on various characterization analyses, the reaction catalytic mechanism was demonstrated to be the result of the non-homogeneous Fanton reaction interaction between Fe3O4 on the ARM surface and H2O2 in solution. Formic acid is the product of the decarboxylation reaction of amoxicillin and its degradation of various organic acids. The formic acid was produced up to 792.38 mg L−1, under the optimal conditions of reaction temperature of 90 °C, reaction time of 30 min, H2O2 concentration of 20 mL L−1, ARM addition of 0.8 g L−1, pH = 7, and rotor speed of 500 rpm. This research aims to provide some references for promoting red mud utilization in antibiotic sludge degradation.

Attapulgite-based MCM-41 zeolite supported Ni-Nb catalysts for hydrogen production by acetic acid steam reforming

Acetic acid steam reforming (AASR) was generally considered as one of the promising technologies for hydrogen production. In this work, the L-lysine-assisted attapulgite-based MCM-41 zeolite (LAMZ) was successfully synthesized by using attapulgite-derived silicon source and the LAMZ-supported Ni-Nb (xNi-yNb/LAMZ) catalysts were prepared via conventional impregnation method. The effects of LAMZ and Nb content on regulating the microstructures and properties of Ni-based catalysts were investigated by various characterizations. Results revealed that the addition of L-lysine could contribute to forming more void structures and increasing specific surface area of LAMZ support, which was beneficial for promoting the dispersion of active sites and enhancing the metal-support interaction. Additionally, Nb optimized the reduction of Ni, increased the concentration of surface-active Ni species, improved the strength of surface Lewis acid and promoted the formation of Ni-NbOx interfaces. Amongst, 5Ni-1Nb/LAMZ exhibited the highest surface Ni0 sites and Ni-NbOx interfaces, which further induces the generation of VO generation and the flow of lattice oxygen. Therefore, the 5Ni-1Nb/LAMZ catalyst presented the highest acetic acid conversion (82.1 %) and hydrogen yield (69.9 %) at reaction conditions of reaction temperature = 750 °C, S/C = 3, WHSV = 19.96 h−1, furthermore, it almost no any inactivation during 55 h of AASR. Additionally, the characterization results of spent catalysts confirmed that 5Ni-Nb/LAMZ possess high coke resistance and anti-sinter capability.

Hydrogen Generation from Waste Aluminum Foil AA 1235 Promoted by Sodium Aluminate in Sodium Hydroxide Solutions

The primary barrier to hydrogen production through the aluminum-water reaction is the oxide layer which forms on the exterior surface of the aluminum. In this work, the passivation was minimized by optimizing the concentration of sodium hydroxide solution (0.3 - 0.5 M) promoted by NaAlO2 at room temperature reaction conditions. The aluminum used is waste aluminum foil AA1235 chips having dimensions of 20 mm x 30 mm. The results showed that the hydrogen production rate increases as the NaOH solution concentration increases. The higher the solution’s pH, the shorter the hydrolysis process of the alumina layer, hence the hydrogen production is faster. Adding NaAlO2 as a promoter could increase the hydrogen production rate compared to sole NaOH, i.e., 11.162 ml/minute and 9.86 ml/minute, respectively. This increase occurred significantly during the fast reaction stage. It indicates that the solution containing NaOH and NaAlO2 work synergistically whereby NaOH can accelerate the reaction rate in the aluminum core and NaAlO2 functions as the booster for producing Al(OH)3.