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In this study, the catalytic effect of the internal surface of reactors constructed from stainless steel (SS310) for hydrogen production via methane decomposition has experimentally been proved and compared with a quartz-lined reactor. The effects of the methane decomposition temperature and volume-hourly-space velocity (VHSV) on hydrogen production, conversion of methane, and initial decomposition rates were investigated in an SS310 lab-scale reactor. Within the duration of the experiments, no change was recorded for hydrogen and methane concentration in all the experiments. The catalytic activity of the SS310 reactor's internal surface increased with increasing methane decomposition temperature (850−950 °C) and decreasing VHSV (37−52 h−1). The as-produced carbon was characterized using surface texture analysis, X-ray, and SEM-EDX.

Pyrolysis product yield and composition are dependent on the characteristics of feedstock and operating parameters. Heating rate is one of the key parameters that has substantial influence on pyrolysis yields and its composition. This study aims to investigate the influence of heating rate on the yield and the composition of pyrolysis products from palm kernel shell feedstock in low, medium and high pyrolysis modes. The pyrolysis experiments were performed at three heating rates ranging from 50 to 275 °C/min via screw-assisted fluidization. The process was optimized at the rotation speed of 50 rpm at 500 °C. A maximum bio-oil yield of 72.86 wt.% was obtained with 275 °C/min heating rate. The liquid yield obtained at 275 °C/min heating rate contained higher proportion of organic phase of approximately 42.21 wt.% than the aqueous phase. The presence of oxygenated compounds in the organic phase at this heating rate was lower than that obtained with low and medium heating rates.

A series of experiments was conducted to study the effect of temperature and feed rate on physicochemical properties and yield of bio-oil. The experiments were performed in a helical screw fluidized bed reactor and about 150-gram palm shell (PS) was pyrolyzed in each run at 275 °C/min heating rate. The first set of experiments was conducted at temperature ranging from 400 to 650 °C without using any inert gas for fluidization. While the second set of experiments were performed at feed rates ranging from 3 to 25 g/min in order to investigate the effects of feed rate on pyrolytic products. Results showed that the bio-oil yield was increased with the increase in temperature and feed rate due to the enhanced biomass volatilization. In a similar vein to this, a greater extent in oxygenates cracking was also noted in the bio-oil. A maximum liquid yield of about 72.84 wt% was obtained at 500 °C, while 72.92 wt% liquid yield was obtained with 25 g/min feed rate. The HHV of bio-oil was also increased from 38.52 to 43.13 MJ/kg when pyrolysis temperature was increased from 400 to 650 °C.

The energy scarcity is exacerbating and needs an urgent solution. The most plausible solution to address the forthcoming energy scarcity is to diversify the energy sources. Developing the water-splitting process (WSP) efficiency depends on solar energy representing "21st-century dream technology". We present a comprehensive review of related papers employing graphitic carbon nitride (g-C

Magnetic hyperthermia therapy (MHT) is a highly promising therapeutic modality for the treatment of different kinds of cancers and malignant tumors. The therapy is based on the concept that; iron oxide nanoparticles deposited at cancer sites can generate heat when exposed to an alternating current magnetic field or near infrared radiation and consequently destroying only the cancer cells by exploiting their vulnerability to heat. The fact that the treatment is at molecular level and that iron oxide nanoparticles provide more guided focus heating justifies its efficacy over treatment such as surgery, radiation therapy and chemotherapy. Nevertheless, the spread of MHT as the next-generation therapeutics has been shadowed by insufficient heating especially at the in vivo stage. This can be averted by modifying the iron oxide nanoparticle structure. To this end, various attempts have been made by developing a magnetic hybrid nanostructure capable of generating efficient heat. However, the synthesis method for each component (of the magnetic hybrid nanostructure) and the grafting process is now an issue. This has a direct effect on the performance of the magnetic hybrid nanostructure in MHT and other applications. The main objective of this review is to detail out the different materials, methods and characterization techniques that have been used so far in developing magnetic hybrid nanostructure. In view of this, we conducted a comprehensive review and present a road map for developing a magnetic hybrid nanostructure that is capable of generating optimum heat during MHT. We further summarize the various characterization techniques and necessary parameters to study in validating the efficiency of the magnetic hybrid nanostructure. Hopefully, this contribution will serve as a guide to researchers that are willing to evaluate the properties of their magnetic hybrid nanostructure.

The ever-increasing CO2 emission has necessitated the search for suitable technologies for CO2 utilization at a low cost. Recently, a novel concept called reactive gas electrosorption (RGE) for energy harvesting from CO2 emission, which could boost the efficiency of a thermal power plant by 5% was proposed by Hamelers and coworkers. The concept involves mixing of air stream with a low CO2 concentration with a stream of high CO2 concentration in an alkaline aqueous electrolyte. However, this concept is faced with the challenges of designs specific for CO2-electrolyte, and inadequate performance of the electrode materials. Therefore, this study showcases electricity generation opportunities from CO2 via RGE and discussed challenges and prospect. The study reveals that the drawback relating to the electrode could be solved using heteroatom doped traditional carbon materials and composite carbon-based materials, which has been successfully used in capacitive cells designed for desalination. This modification helps to improve the hydrophilicity, thereby improving electrode wettability, and suppressing faradaic reaction and co-ion repulsion effect. This improvement could enhance the charge efficiency, sorption capacity durability of electrodes and reduce the energy loss in RGE. Moreover, intensification of the membrane capacitive deionization (MCDI) process to obtain variances like enhanced MCDI and Faradaic MCDI. Hybrid capacitive deionization (HCDI) is also a promising approach for improvement of the capacitive cell design in RGE. This intensification can improve the electrosorption capacity and minimize the negative effect of faradaic reaction. The use of alternative amine like Piperazine, which is less susceptible to degradation to boosting CO2 dissolution is also suggested.

Empty fruit bunches (EFB) have great potential to be used as a renewable fuel. Its current low rate of utilization due to high moisture content and low calorific value (CV) can be overcome via a thermal pretreatment, i.e., torrefaction. This study investigated the effects of torrefaction temperature (225, 250, 275, and 300 °C), residence time (20, 40, and 60 min) and particle size (< 106, 106–250, and 500–700 μm) on EFB’s final product distribution and their characteristics in a fixed bed. Structural and thermal properties of the torrefied EFB at different temperatures were determined. Optimum temperature to produce torrefied EFB was identified at 225 °C, while optimum residence time and particle size were 20 min and 500–700 μm, respectively, for a maximum mass (90.3 wt.%) and energy (98.8%) yields. The mass and energy yields of torrefied EFB decreased with increasing temperature and residence time, but increased with increasing particle size of EFB. It was found that the torrefaction temperature had the greatest influence on mass and energy yields of torrefied EFB compared with residence time and particle size. In addition, the study revealed that moisture content had reduced, and carbon content increased with an increasing torrefaction temperature, but those of the O/C ratio, and H and O contents decreased, resulting in an improved CV up to 24.6 MJ kg−1 from its raw form of 17.6 MJ kg−1. The findings obtained are useful for future upscaling of EFB-based solid fuel production.

Nowadays, methane cracking in the presence of an efficient catalyst is one of the most investigating areas aiming hydrogen and nanocarbon synthesis. This research contribution systematically investigated the influence of methane partial pressure (PCH4), decomposition temperature, and weight of Ni/SiO2 nanocatalyst (n-Ni/SiO2) on carbon nanotube (CNT) yield. The optimum reaction condition for optimal methane cracking resulted in maximum CNT yield is derived using Design Expert Software. A series of experiments conducted to develop a quadratic polynomial model for CNT yield using response surface methodology. Surprisingly, the optimum catalyst quantity was the lowest (0.30 g) in the experimented parameter range, which exhibited the highest CNT production at 610 °C temperature and 0.8 atm PCH4. The minimal catalyst quantity for the optimum CNT production, which needs only 0.26% of the total volume of the pilot plant reactor, is a breakthrough finding in methane cracking research. It could help to overcome the reactor blockage limitation issues of the process in large scale applications. Thanks to the uniquely supported n-Ni/SiO2 catalyst prepared via co-precipitation cum modified Stober method. The fresh and used catalysts investigated using different types of characterization techniques such as XRD, BET, Raman spectra, HRTEM, and FESEM-EDX. Characterization results evidenced the presence of differently structured CNTs formed at optimum reaction conditions.

The production of bio-oil from palm shell pyrolysis was investigated using a helical screw fluidized bed reactor setup. This study was done by investigating the effects of particle size, pyrolysis time and vapor residence time on pyrolysis product yields. The pyrolysis experiments were performed at different particle sizes, pyrolysis times and vapor residence times from 0.25 mm to 10 mm; 20 min to 60 min and 0.25 s to 15 s, respectively. The optimum condition for PS pyrolysis in helical screw fluidized bed reactor is at 2 mm particle size, 30 min pyrolysis time and 0.25 s vapor residence time to produce PS derived bio-oil of the highest yield of 73.86 wt% and higher heating value of 43.14 MJ/kg. Here, we report of the capability of helical screw fluidized bed reactor in handling large biomass particle size ranging up to 10 mm with marginal deteriorations of less than 1% and 3% for bio-oil yield and higher heating value respectively. This feature was attributed to the screw propeller design system in helical screw fluidized bed reactor which provided high mass and heat transfer at large particle size range which is 5 times of the particle size limit as recommended in previous studies. This finding would enable the possibility of helical screw fluidized based pyrolysis to be done in the absence of biomass size reduction processes to reduce process cost and complexity.

The potential of producing high calorific value (CV) solid fuel was investigated in a helical screw rotation-induced (HSRI) fluidized bed reactor based on mechanical fluidization. The study revealed that the HSRI torrefaction improved the torrefied product properties. For the 40 and 0 rpm conditions, the CV, fixed carbon, and ash contents of torrefied solid fuel increased with an increase in temperature. In contrast, volatile matter, moisture content, mass and energy yields decreased. The CV of torrefied solid fuel increased by a factor of 1.43 and 1.58 at 280 °C for the 40 and 0 rpm conditions, respectively. HSRI torrefaction enhanced the removal of hydroxyl functional group. HSRI torrefaction improved the hydrophobicity of the torrefied solid fuel. Therefore, the HSRI fluidized bed reactor promotes uniform temperature distribution, a higher heat transfer rate within the sample particles in the reactor, and a homogenous torrefied solid product compared to the fixed bed reactor.

This study explored the predictive modelling of the pyrolysis of rice husk to determine the thermal degradation mechanism of rice husk. The study can ensure proper modelling and design of the system, towards optimising the industrial processes. The pyrolysis of rice husk was studied at 10, 15 and 20 °C min−1 heating rates in the presence of nitrogen using thermogravimetric analysis technique between room temperature and 800 °C. The thermal decomposition shows the presence of hemicellulose and some part of cellulose at 225–337 °C, the remaining cellulose and some part of lignin were degraded at 332–380 °C, and lignin was degraded completely at 480 °C. The predictive capability of artificial neural network model was studied using different architecture by varying the number of hidden neurone node, learning algorithm, hidden and output layer transfer functions. The residual mass, initial degradation temperature and thermal degradation rate at the end of the experiment increased with an increase in the heating rate. Levenberg–Marquardt algorithm performed better than scaled conjugate gradient learning algorithm. This result shows that rice husk degradation is best described using nonlinear model rather than linear model. For hidden and output layer transfer functions, ‘log-sigmoid and tan-sigmoid', and ‘tan-sigmoid and tan-sigmoid' transfer functions showed remarkable results based on the coefficient of determination and root mean square error values. The accuracy of the results increases with an increasing number of hidden neurone. This result validates the suitability of an artificial neural network model in predicting the devolatilisation behaviour of biomass.

Production of bio-jet fuel from triglycerides (TGs) based vegetable oils have recently received increased attention from research and industries because of its renewability and environmental benefits. Catalytic deoxygenation (DO) is a suitable way to produce bio-jet fuel from TGs. Presently, the main challenges faced by DO are the optimized selection of feedstocks, catalysts, reaction pathways and parameters. This review includes discussion on the feedstock and assessment of several potential catalysts: noble metals, sulphided, non-sulphided for DO of TGs. This assessment elucidates the model compounds of TGs, effect of operating parameters, potential catalysts and different DO reaction pathways to attain optimum yield and selectivity of desired products. In addition, some relevant discussion of TGs derived jet fuel specification, characteristics and fuel properties are also discussed. Overall, this review provides a comprehensive discussion on DO of TGs based vegetable oils in enhancing alternative jet fuel production in all relevant technical aspects.

In this study, thermal liquefaction of natural rubber was performed using different alcohols to produce valuable intermediate product. The experiment was conducted in autoclave reactor at different temperatures (250–375 °C), different solvent-to-natural rubber mass ratios (0.5:1 to 4:1), and at different reaction times (15–75 min.). The results showed the maximum liquid yield of 89.53 wt.% was obtained by using propanol at optimum conditions. Around 51.23% and 10.65% of liquid comprised of D-limonene and Isoprene respectively, which are being used as potential feedstock in different industrial sectors. Besides these compounds, the liquid product also consisted other hydrocarbon such as aromatics, alkyls, and alkene with high HHV (46 MJ/kg), and low oxygen contents (1.02%). These properties make this liquid suitable to be used for substitution the conventional fossil fuels. In addition, alcohol solvents played an important role to facilitate the liquefaction process by providing milder process conditions and hydrogen donor. Among the solvents, propanol has significant improvement on the liquid yield, solvent recovery and energy density.

Hydrogen peroxide (H2O2) is commercially produced by catalytic oxidation of anthrahydroquinone, which is energy-intensive. Electrochemical production of hydrogen peroxide production through oxygen reduction reaction (ORR) is a sustainable approach, primarily due to its significance in energy conversion systems such as fuel cells. Low temperature fuel cells use graphite as a cathode for H2O2 synthesis. However, the catalytic activity of a graphite cathode for a two-electron oxygen reduction reaction must be improved. Nitrogen doping is an efficient approach to modify the electrochemically active surface of the graphite cathode. Therefore, quantum chemical approaches are essential to comprehend the molecular nature of the processes at the cathode. DFT/B3LYP/6-31G* method was employed and bond dissociation energy (BDE) analysis was performed to determine the feasibility of H2O2 production at graphite and nitrogen-doped graphite (Graphite-N) cathodes. According to the suggested mechanism, oxygen adsorption is the first step of the ORR. Calculated values showed that with energy value of 23.50 kcal/mol oxygen adsorption at the Graphite-N cathode is energetically more favorable than the graphite cathode (Ead = 65.08 kcal/mol). Considering the ORR mechanism, a second-electron oxygen reduction is identified as a key step for both H2O and H2O2 production. Therefore, BDEs were compared at the second-electron oxygen reduction step. On average, − 320.92 and − 286.04 kcal/mol of BDEs for graphite and Graphite-N cathodes showed the feasibility of H2O2 production at the Graphite-N cathode. The results are in agreement with the literature. Thus, it is concluded that nitrogen doping of the graphite cathode increases the feasibility of H2O2 production.

Redox mediators supply an effective way to promote electrons (and protons) transport between the electrode and substrate without being in direct physical contact with the electrode. Here, the carbon-based electrodes with Amberlyst-15 as the redox mediator were used in the electrocatalytic reduction to investigate their ability to indirectly convert glycerol into 1,2-propanediol. The process aims to study the influence of different activated carbon compositions (60%, 70%, 80%, and 90% of total weight) in the activated carbon composite (ACC) electrodes on the electrochemical properties, reaction mechanisms, and selectivity of the yielded products. Their electrochemical behavior and physicochemical properties were determined by cyclic voltammetry (CV) and chronoamperometry (CA), followed by FESEM-EDX for the selected ACC electrode. Electroactive surface area (EASA) plays a role in glycerol mass transport and electrons transfer. EASA of 60ACC, 70ACC, 80ACC, and 90ACC (geometrical surface area of 0.50 cm

The present investigation aimed to study the physicochemical characteristics of supported catalysts comprising various percentages of zinc dispersed over SiO2. The physiochemical properties of these catalysts were surveyed by N2 physisorption (BET), thermogravimetry analysis (TGA), H2 temperature-programmed reduction, field-emission scanning electron microscopy (FESEM), inductively coupled plasma-optical emission spectrometry (ICP-OES), and NH3 temperature-programmed desorption (NH3-TPD). In addition, to examine the activity and performance of the catalysts for the hydrodeoxygenation (HDO) of the bio-oil oxygenated compounds, the experimental reaction runs, as well as stability and durability tests, were performed using 3% Zn/SiO2 as the catalyst. Characterization of silica-supported zinc catalysts revealed an even dispersion of the active site over the support in the various dopings of the zinc. The acidity of the calcinated catalysts elevated clearly up to 0.481 mmol/g. Moreover, characteristic outcomes indicate that elevating the doping of zinc metal led to interaction and substitution of proton sites on the SiO2 surface that finally resulted in an increase in the desorption temperature peak. The experiments were performed at temperature 500 &deg, C, pressure 1 atm, weight hourly space velocity (WHSV) 0.32 (h&minus, 1), feed flow rate 0.5 (mL/min), and hydrogen flow rate 150 (mL/min). Based on the results, it was revealed that among all the prepared catalysts, that with 3% of zinc had the highest conversion efficiency up to 80%. However, the selectivity of the major products, analyzed by gas chromatography flame-ionization detection (GC-FID), was not influenced by the variation in the active site doping.

International audience; Glycerol is a by-product produced from biodiesel, fatty acid, soap and bioethanol industries. Today, the value of glycerol is decreasing in the global market due to glycerol surplus, which primarily resulted from the speedy expansion of biodiesel producers around the world. Numerous studies have proposed ways of managing and treating glycerol, as well as converting it into value-added compounds. The electrochemical conversion method is preferred for this transformation due to its simplicity and hence, it is discussed in detail. Additionally, the factors that could affect the process mechanisms and products distribution in the electrochemical process, including electrodes materials, pH of electrolyte, applied potential, current density, temperature and additives are also thoroughly explained. Value-added compounds that can be produced from the electrochemical conversion of glycerol include glyceraldehyde, dihydroxyacetone, glycolic acid, glyceric acid, lactic acid, 1,2-propanediol, 1,3-propanediol, tartronic acid and mesoxalic acid. These compounds are found to have broad applications in cosmetics, pharmaceutical, food and polymer industries are also described. This review will be devoted to a comprehensive overview of the current scenario in the glycerol electrochemical conversion, the factors affecting the mechanism pathways, reaction rates, product selectivity and yield. Possible outcomes obtained from the process and their benefits to the industries are discussed. The utilization of solid acid catalysts as additives for future studies is also suggested.

Glycerol electrooxidation has attracted immense attention due to the economic advantage it could add to biodiesel production. One of the significant challenges for the industrial development of glycerol electrooxidation process is the search for a suitable electrocatalyst that is sustainable, cost effective, and tolerant to carbonaceous species, results in high performance, and is capable of replacing the conventional Pt/C catalyst. We review suitable, sustainable, and inexpensive alternative electrocatalysts with enhanced activity, selectivity, and durability, ensuring the economic viability of the glycerol electrooxidation process. The alternatives discussed here include Pd-based, Au-based, Ni-based, and Ag-based catalysts, as well as the combination of two or three of these metals. Also discussed here are the prospective materials that are yet to be explored for glycerol oxidation but are reported to be bifunctional (being capable of both anodic and cathodic reaction). These include heteroatom-doped metal-free electrocatalysts, which are carbon materials doped with one or two heteroatoms (N, B, S, P, F, I, Br, Cl), and heteroatom-doped nonprecious transition metals. Rational design of these materials can produce electrocatalysts with activity comparable to that of Pt/C catalysts. The takeaway from this review is that it provides an insight into further study and engineering applications on the efficient and cost-effective conversion of glycerol to value-added chemicals.

Thermogravimetric analysis (TGA) for solid-gas reactions is well formalized and of ubiquitous use. However, the use of volatile samples in TGA often results in pre-loss of volatile sample by evaporation prior to reaching the specified thermal conditions of analysis. Therefore, sample encapsulation method was proposed as an innovative technique to address this issue. This technique was shown to provide a continuous and delayed release of vaporized samples over the range of elevated temperature through the progressive loosening of the hermetic seal of metal capsule. This effect can be enhanced by using capsule with higher material hardness and smaller surface area for sample evaporation. Application of this method in catalytic phenol reduction has shown an increase in benzene yield from 19.2 mol% to 46.5 mol% when phenol is encapsulated by tin cylinder. Based on these findings, delayed volatiles release phenomenon may lead to further opportunities in the area of thermochemical kinetics study for fuel processing such as gasification, carbonization, reforming or petrochemical reactions that involve catalyst activation at high temperature and use of volatile samples such as fuel model compounds in TGA setup.

Rational design and synthesis of cheap, noble metal-free, thermal/hydrothermal stable and active catalyst for efficient hydrogenation and hydrogen production reaction is crucial towards renewable and sustainable energy generation. This gives the use of molybdenum carbide nanoparticle considerable attention as an alternative to noble metals. However, the industrial application is not yet feasible due to insufficient stability and activity coupled with the lack of detailed understanding of the reaction mechanism. This work discusses the effect of the operating parameters on the properties and morphology of molybdenum carbide nanoparticle, as well as their impact on the catalytic activity. Critical issues such as structural diversity, surface properties, and multiscale reaction modeling are also discussed for better understanding of the reaction mechanism. This is a promising strategy towards synthesis of cost-effective and efficient catalysts for renewable and sustainable energy production.

Biomass pyrolysis processes for bio-oil production were commonly done using batch, semi-continuous or continuous process. However, past studies have shown many concerning issues in regard to the use of batch process such as high residence time, product inconsistencies across batches, high labor cost and difficulty in industrial scale up. With these, scientists are now placing a greater interest and focus in the study of semi-continuous and continuous pyrolysis processes with their commercialization and industrialization as the major outcomes. The production rates of semi-continuous and continuous pyrolysis process are certainly more superior to the former owing to their facile in-situ withdrawal of products during pyrolysis. Nevertheless, they are of higher design complexities, thus requiring a better controllability of the operating parameters. This article reviewed on semi-continuous and continuous pyrolysis process through several perspectives: feed treatment, feeding system, operating parameters, reactor technologies and additional product separation devices. The expressed contents of this review will provide an understanding of the technical aspect of pyrolysis process comprehensively, starting from the material treatment to the end of product collection.

A visible light responsive photocatalyst, nano-sized copper doped TiO2/ZnO, was synthesized by sol gel method. It was characterized in terms of thermal stability, crystalline phase, crystal size, morphology, surface area, UV–Vis DRS and band gap. The results showed that the synergistic effect of copper ions considerably narrowed the band gap of the synthesized photocatalyst compared to TiO2/ZnO. Its photoactivity was then evaluated by measuring degradation efficiency of methyl orange (MO) and methylene blue (MB) in terms of colour, COD and TOC removal. The synergistic or antagonistic effects of different combinations of dye and catalyst concentrations, pH, intensity of light irradiation and reaction time on photoactivity of Cu-TiO2/ZnO were also investigated. The highest photoactivity achieved was 85.45% of colour, 70.56% of COD and 48.70% of TOC removal for MO and 73.20% of colour, 59.92% of COD and 38.77% of TOC removal for MB under optimal conditions.

In this study, the natural rubber (NR) was liquefied to produce liquid fuels using hydrous pyrolysis technique. The study was performed in the autoclave batch reactor at different temperatures (300–400 °C), with different water to natural rubber mass ratios (1:1–5:1) and different reaction times (15–75 min). The effect of different parameters then was evaluated on the liquid product in term of quantity and quality. The results showed that the highest liquid yield of 76 wt% was obtained at temperature, H2O/material mass ratio and time of 375 °C, 3:1 and 30 min respectively. Among the parameters, temperature was found to be the most important parameter, showing a notable positive effect on the liquid oil quality and quantity. The characterization results showed that the oil had high energy density, low oxygen and sulfur contents, and non-acidic. The GC–MS analysis showed that the obtained oil was dominated by alkenes, aromatics and alkyls. From all characteristic results it showed that the oil from NR was more suitable to be used as fuel compare to the oil derived from scrap tire, where the study on hydrous pyrolysis of scrap tire was also provided in this manuscript as comparative study. In addition, the production of oil from the hydrous pyrolysis of NR in Malaysia could add to the energy potential about 15 PJ/year or equivalent to 2.5 million barrels of oil per year.