Solid Conversion Research Articles

A novel computer vision and point cloud-based approach for accurate structural analysis of a tall irregular timber structure

Wood material has been widely used in critical heritage structures such as pagodas, totem poles, and large-scale sculptures. Conducting rigorous structural analysis is crucial to protect these structures in high-seismic regions. Typically, these types of structures are modeled using an equivalent finite element (FE) model which used simple cylinder with a constant cross section equal to the average of the top and bottom cross section. However, simplified equivalent FE models may not accurately consider the irregularities and complexities of these structures. In this paper, advanced computer vision and point cloud techniques were adopted to accurately and rapidly construct a FE model of a 30-meter irregular timber sculpture. This was achieved using video scans, computer vision-aided 3D reconstruction, point cloud processing, and mesh to solid element conversion. The refined FE model was used to conduct capacity check, mesh sensitivity study, pushover analysis, and response spectrum analysis. The results of the refined FE model were compared to an equivalent FE model. The results show: 1) the proposed numerical modeling methodology for structural analysis can efficiently and accurately measure the dimension of the irregular sculpture up to 98.2 % accuracy; 2) the lateral stiffnesses of the 30-meter irregular sculpture vary significantly (up to 42.6 %) from one direction to the other; 3) the equivalent FE model overestimated the shear and moment capacities by 20.6 % and 13.2 %, respectively; 4) on average, the equivalent FE model overestimated the shear and moment demands by 8.9 % and 5.5 %, respectively. Overall, the proposed application has demonstrated a fast, economical and accurate method to conduct seismic evaluation and design for irregular structures.

Delaying cyclization of polyacrylonitrile by boric acid for sulfurized poly(acrylonitrile) cathode materials

Sulfurized poly(acrylonitrile) (SPAN) has become one of the most promising cathode materials in rechargeable Lithium-Sulfur (Li-S) batteries due to their inhibited polysulfide dissolution, high sulfur utilization and excellent electrochemical performance via unique solid–solid conversion mechanism. However, the sulfur content of SPAN (<50 %) is still one of the significant reasons that restrict the electrochemical performance and practical applicability. In this paper, a small amount of boric acid (HBO) was introduced into the precursor of SPAN cathode materials easily before heat-treating, to increase the sulfur content and improve the electrochemical performance. Meanwhile, the results of first principles calculation suggested that the increase of sulfur content of SPAN was derived from the delayed cyclization of polyacrylonitrile (PAN) by HBO. We also discovered when the additive amount of HBO was 1.5 % of PAN mass, the SPAN cathode material possessed high sulfur content up to 54.24 wt%, and delivered prominent reversible electrochemical performances of 714 mAh/g at 0.2C and 734 mAh/g at 0.1C with high Coulombic efficiency. In summary, we proposed a simple and easy method to improve sulfur content and introduced a new strategy for the design of high-sulfur content and high-performance SPAN cathode materials.

Creative synthesis of pH-dependent nanoporous pectic acid grafted with acrylamide and acrylic acid copolymer as an ultrasensitive and selective riboflavin electrochemical sensor in real samples

In current research, an innovative pectic acid was grafted with poly (acrylamide-co-acrylic acid) [PA-g-poly (AAm-co-AA)] nanoporous membrane using a free radical-mediated grafting copolymerization process. The optimized parameters for the grafting copolymerization reaction such as initiator concentration, monomer concentrations, polymerization reaction time, and temperature were studied. Additionally, the solid content, graft percentage, and conversion were calculated. The unique polymeric membrane was characterized using Fourier-transform infrared spectroscopy (FT-IR), thermal gravimetry (TG), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) supported by energy dispersive X-ray spectroscopy (EDX). The formulated novel PA-g-poly (AAm-co-AA) had a nanoporous structure with a diameter of 113 nm. pH-dependent swelling and biodegradation measurements were also studied. The electrochemical characterizations of PA-g-poly (AAm-co-AA) were conducted through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Furthermore, the screen-printed electrode (SPE) was modified with pure PA and the new generation of its grafted polymeric nanoparticles to detect and quantify the concentration of riboflavin (RF) in real samples using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The modified electrode showed two linear concentration ranges from 0.01 - 2 nM and 2 – 90 nM with low detection limits (LODs) of 0.004 and 0.97 nM, respectively, demonstrating high sensitivity. Besides, the fabricated sensor exhibited more selectivity, simplicity, great reproducibility, repeatability, and good stability. Finally, the PA-g-poly (AAm-co-AA)-modified SPE based sensor was effectively used in real sample analysis of egg yolk, milk, and vitamin B2 drugs with good recovery rates.

The process optimization and exergy efficiency analysis for biogas to renewable hydrogen by chemical looping technology

The study on biogas-Chemical Looping Hydrogen Production (biogas-CLHP) highlights its potential to produce high-purity hydrogen with recycling waste bioenergy. It delves into the gas-solid reaction characteristics and optimizes crucial process parameters for the fixed-bed CLHP system. Movement rate equations for the reaction fronts of Fe2O3-Fe3O4 (Rf1), Fe3O4-FeO (Rf2), and FeO-Fe (Rf3) are formulated, aiding in clarifying CO breakthrough curves. The identified convergence temperatures (Tm) under CO and H2 atmospheres are 916 °C and 907 °C, respectively. Rf1 and Rf2 converged above Tm, which leads to the disappearance of the Fe3O4 region in oxygen carrier (OC) beds. A theoretical model for calculating the reduction solid conversion (Xaver) is established, accurately characterizing Xaver under varying reaction times, H2/CO ratios, and temperatures. By using the Particle Swarm Optimization (PSO) algorithm and thermodynamic analysis, the study determines the optimal length-radius ratio (L/r), reduction temperature (T), and H2/CO ratio (α) for the OC bed as 12.5, 916 °C, and 0.72, respectively, at which a maximum conversion ratio of 43.55 % is achieved. Based on optimal parameters, the results of Aspen simulation reveal energy and exergy efficiencies of 74.9 % and 70.8 %. Generally, this research comprehensively outlines the process dynamics, optimizes key parameters, and evaluates exergy efficiency of the biogas-CLHP system.

Optimization of traditional market solid waste conversion process into hydrochar using hydrothermal carbonization technology

Abstract In this study, an analysis was carried out to determine the optimum conditions for the hydrothermal carbonization process of traditional market waste using response surface methodology central composite design. The hydrothermal carbonization process was carried out at temperatures (180, 215, 250°C), process times (30, 60, 90 minutes), and a ratio (waste: water media) of 0,5. The results of response surface analysis show that temperature and process time are parameters that significantly affect the quality of hydrochar. Increasing temperature and process time resulted in a decrease in hydrochar weight from 67,01 to 40,77 grams. Furthermore, there was an increasing heating value of hydrochar from 18,87 to 30,5 MJ/Kg. The optimization formulation of the hydrothermal carbonization process of traditional market waste was obtained at a temperature of 181,133°C and a process time of 30 minutes with a prediction value of weight and heating value obtained, namely 61,39 grams and 23 MJ/Kg.

Disruptive Semi-Solid Lithium Sulfur Battery Cell Design with Fully Separated Anolyte and Catholyte

Lithium-Sulfur-Batteries (LSBs) have been discussed as one of the most promising post-lithium-ion-battery technologies in literature for the last decade due to their high theoretical specific energy of 2600 Wh/kg. However, several drawbacks still exist in case of liquid LSB-concepts, especially cycling stability with low electrolyte excess in combination with a reasonable sulfur utilization plus cycle stability still hinders the commercial breakthrough of this battery technology. One main reason for both issues is the dissolution of the active material, sulfur, as polysulfides in the electrolyte, which leads to the so-called polysulfide shuttle that comprises polysulfide diffusion through the cell to the lithium metal anode resulting in decomposition reactions, and therefore, loss of active material. Several electrolyte approaches in order to limit polysulfide dissolution have been developed over the last 5-10 years, however, those electrolyte formulations usually lead to a strong lithium metal corrosion. Electrolytes that enable stable cycling of lithium metal batteries in combination with a nickel manganese cobalt oxide cathode have been successfully developed, however, they are ususally not compatible with the polysulfides of Li-S batteries. Hence, decoupling the anolyte from the catholyte has been much desirable. Recently introduced solid-state lithium sulfur batteries based on sulfidic solid electrolytes might overcome some challenges of conventional liquid LSBs since no formation or diffusion of polysulfide species can take place, and very high sulfur utilization have been already reached. However, solid-state LSBs have not been cycleable so far when a thin layer of solid electrolyte and lithium metal anode (without indium) were employed, especially in pouch cells, due to the formation of lithium dendrites, resulting in short circuits.Herein, a completely new battery design, a “semi-solid”-LSB, is presented. The concept combines the advantages of liquid and solid state LSBs. On the cathode side, an electrode comprising carbon, sulfur and sulfidic solid electrolyte (argyrodite) enables a solid to solid conversion of sulfur resulting in a complete suppression of the polysulfide shuttle.On the anode side, a liquid electrolyte enabling stable cycling of a lithium metal anode is employed. A careful design of the liquid electrolyte is crucial in order to obtain high stability of the liquid electrolyte against the lithium metal anode as well as to avoid side reaction between the solid electrolyte of the cathode and the liquid electrolyte. Different electrolytes are discussed for the new cell design and proof of concept was successfully reached in coin cells leading to 100 cycles with a stable coulombic efficiency of over 99 % which outperforms the majority of previously published Li-S cycling data. In addition, the concept was also transferred into first semi-solid lithium sulfur-pouch cells which is an important step in the direction of practical applications.

Collaborative modelling of gas-solid reacting flow in a fuel reactor equipped with process controllers in chemical looping combustion/conversion

Chemical reactors usually feature complex internal reacting flows, and they are usually equipped with process controllers to stabilise their operations, especially for highly dynamic reactors including chemical looping combustion/conversion (CLC). However, their dynamic internal states are not well understood due to the lack of reliable research tools. In this work, for the first time, an innovative numerical collaborative model is developed to describe the reacting flow details and simulate the response to a process controller. The collaborative model is applied to a fuel reactor (FR) in a CLC to demonstrate its effectiveness. The detailed internal flow patterns in the FR are obtained and described by the three-phase reacting flow CFD model, and the circulating rate of oxygen carrier (OC) is controlled and optimised by the fuzzy logic controller (FLC). The controller is designed to operate at varying control time intervals, 1 s, 2 s, and 5 s, to study the optimal frequency for data sampling and feedback. The efficiency of the controller to the FR is tested in terms of OC circulation, gas components and the general performance of the reactor. The results show that the stability of OC circulating rate and performance are effectively improved by the process controller; among the three control intervals, the 2 s interval shows the highest feasibility and capability of maintaining stable OC circulation and CO2 yield in the FR. Quantitatively, compared to the base case without a controller, the range of OC circulating rates has been narrowed from [0.014, 0.534] to [0.018, 0.385] in control case A, [0.075, 0.342] in control case B, and [0.004, 0.530] in control case C. Meanwhile, the CO2 yield increased from 86.93 % in the base case to 87.98 % in control case A, 88.16 % in control case B, but decreased to 85.4 % in control case C due to poor controlling performance. The combustion efficiency increased from 84.20 % in the base case to 84.87 % in control case A, 86.22 % in control case B, and 85.88 % in control case C. Among all control cases, control case B presents the narrowest data range and highest efficiency, indicating optimal control performance in improving OC circulation stability. The deviation of OC circulating rate values decreases from 0.123 to 0.058, and the CO2 yield increases from 86.93 % to 88.16 % in control case B with a 2 s interval. This work provides a new cost-effective tool for real-time simulating and controlling the reacting flow system including CLC for clean combustion and solid wastes conversion.

Tetraphenylethene-based mononuclear aggregation-induced emission (AIE)-active mechanofluorochromism gold(I) complexes with different auxiliary ligands

In this study, a series of tetraphenylethene-containing gold(I) complexes with different auxiliary ligands have been synthesized. These complexes were characterized using a variety of techniques including nuclear magnetic resonance spectroscopy, mass spectrometry, and single crystal X-ray diffraction. Their aggregation-induced emission (AIE) behaviors were investigated through ultraviolet/visible and photoluminescence spectrum analyses, and dynamic light scattering measurements. Meanwhile, their mechanofluorochromic properties were also studied via solid-state photoluminescence spectroscopy. Intriguingly, all these mononuclear gold(I) molecules functionalized by tetraphenylethene group demonstrated AIE phenomena. Furthermore, five gold(I) complexes possessing diverse auxiliary ligands exhibited distinct fluorescence changes in response to mechanical grinding. For luminogens 2–5, their solids showed reversible mechanofluorochromic behaviors triggered by the mutual transformation of crystalline and amorphous states, while for luminogen 1, blue-green-cyan three-color solid fluorescence conversion was realized by sequential mechanical grinding and solvent fumigation. Based on this stimuli-responsive tricolored fluorescence feature of 1, an information encryption system was successfully constructed.

Multi-dimensional CFD-Mask R-CNN and CFD-watershed segmentation approach for multiphase non-catalytic gas-solid reactions: A case study for hydrogen reduction of porous iron oxide pellets

The direct reduction of iron oxide (DRI) using hydrogen is a promising method for clean steelmaking. Previous studies used one-dimensional models to explore this non-catalytic gas–solid reaction, but they lacked accuracy in assessing the impact of pellet shape. To tackle this issue, a multi-dimensional computational fluid dynamic (CFD) method has been employed, integrating a novel porous three-interface unreacted shrinking core model (USCM) to explore the effects of pellet shape through multiphase reactions of Fe2O3 → Fe3O4 → FeO → Fe by pure hydrogen. The model incorporates Knudsen, molecular, and effective diffusion mechanisms, alongside a continuous porosity function. Validation against previous experiments within a temperature range of 800–1000 °C and varying porosity is performed by solving four partial differential equations (PDEs) of mass and momentum balance in a porous media using the finite element method (FEM). Subsequently, a dataset comprising 754 images of pellets from the industrial DRI unit is collected and applied for the mask region-based convolutional neural network (Mask R-CNN) algorithm coupled with CFD, to draw geometries and simulate DRI to study indentations and protrusions of pellets. Furthermore, watershed segmentation is applied to investigate the shapes and real sizes of pellets from their images. The Mask R-CNN achieves intersection over union (IoU), precision, and recall percentages of 86.1 %, 87.3 %, and 87.2 % on average, respectively. Pellet shape investigations reveal notable discrepancies in wustite phase profiles and porosity. A nuanced impact is discerned regarding the DRI in 2D shape deviation, while 3D model errors in solid conversion time range from 3 % to 12.8 %.

Polymerised forms in the zirconium conversion coatings on cold-rolled steel: proof of concept

This study validates the proposed polymerised structure, including tetrameric polynuclear species, of solid amorphous oxyhydroxide zirconium conversion coatings on cold-rolled steel using ToF-SIMS. Tetramers are formed at pH near 4 (and possibly higher), with thickness increasing over extended conversion times. EIS in simulated acid rain further demonstrates that optimal coating formation requires a pH of at least 4 and a sufficient conversion time for adequate thickness, confirmed by the high-frequency EIS loop. Tetramer forms were not observed when the coatings were prepared at lower pH or shorter conversion time, proving that the polymerisation step is crucial for obtaining the coatings offering adequate corrosion protection.

Two‐dimensionalization of 3D perovskites for passive narrowband Photodetection

AbstractIn the rapidly advancing field of information technology, passive sensors with the exemption of external power input can serve as intelligent instruments for end‐node data acquisition. 3D perovskites have been recognized as a superior optoelectronic material but suffering from notorious instability due to their “soft lattice” nature. Replacing by their 2D counterparts in these photo‐sensing applications can boost the reliability level. However, traditional fabrication for 2D perovskite relay on wet chemistry methods, exhibiting complication, and inefficiency in making high‐quality films for device integration. This study unveils a new solid–solid conversion routing toward a direct transformation from 3D orientated films into 2D highly crystalline configuration, based on a spontaneous lattice regulation mechanism through an amine steam treatment. The resultant 2D film exhibits greater orientational micromorphology and a distinct monochromatic narrowband light sensing behavior after integration into a self‐powered photodetector. This method on perovskite conversion bears the promise of advanced future‐manufacturing for high‐performance photonic sensing.image

Alcohol formaldehyde resin solid acid catalytic conversion of biomass into furan compounds

The conversion of waste lignocellulosic biomass into biomass platform chemicals is very promising. In this work, a novel resin-based solid acid catalyst was obtained by condensation of furfuryl alcohol with furfural, and mild calcination and sulfonation process. Then it was used to convert sugars and biomass to obtain furan compounds. Results showed that the solid acid with a furfural to furfuryl alcohol molar ratio of 3:1 is an irregular mesoporous material, with a specific surface area of 134.18 m2/g and an acid content of 2.723 mmol/g, which is extremely stable below 200 °C. 82.2 % (from fructose), 15.8 % (from glucose), 10.0 % (from cellobiose) yields of 5-HMF and 35.5 % (from xylose) yield of furfural could be obtained at 160 °C for 2 h. It can be reused more than 5 times and can restore the best catalytic effect after re-sulfonation. Notably, in the catalytic conversion of rice husk, rice straw, camphor tree branch and leaves under typical reaction conditions, 5-HMF and furfural was in yields of 9.4–24.5 % and 20.3–47.9 %, respectively. Moreover, a 10 % water dropwise to solvent can effectively promote the catalytic conversion of biomass, while there is a significant inhibitory effect after it exceeds 20 %.

In Situ Construction of CdS/g-C3N4 Heterojunctions in Spent Thiolation@Wood-Aerogel for Efficient Excitation Peroxymonosulfate to Degradation Tetracycline.

Pollutant treatment, hazardous solid waste conversion, and biomass resource utilization are significant topics in environmental pollution control, and simultaneously achieving them is challenging. Herein, we developed a "from waste absorbent to effective photocatalyst" upcycle strategy for nontoxic conversion of Cd(II) adsorbed on thiolation@wood-aerogel (TWA) into CdS/g-C3N4 heterojunctions through the in situ chemical deposition high-temperature carbonization combined conversion method to overcome the above problems simultaneously. We used Schiff base reaction to graft l-cysteine into dialdehyde@wood-aerogel to prepare TWA with a high Cd(II) adsorption capacity (600 mg/L, 294.66 mg/g). Subsequently, the spent Cd(II)-loaded-TWA was used as a substrate for in situ construction of Cd(II) into CdS/g-C3N4 heterojunction for activating peroxymonosulfate (PMS) under simulated sunlight [simulated solar light (SSL)], achieving efficient tetracycline (TC) degradation (20 mg/L, 95.32%). The Langmuir and pseudo-second-order models indicate single-layer chemical adsorption of Cd(II) on the TWA adsorption process. In the PMS/SSL system, CdS/g-C3N4@TWA efficiently and rapidly degraded TC via an adsorption-photocatalytic synergistic degradation mechanism. The used CdS/g-C3N4@TWA has a good biocompatibility. This study proposed design and preparation of a new type of wood aerogel absorbent and provided a novel upcycling strategy for innovative use of the spent waste adsorbent.

Ionic liquid reinforced NaSICON-type oxide electrolyte films enabling solid state conversion metal fluoride-lithium batteries

Solid-state batteries (SSBs) with metal fluoride cathodes are an exciting combination due to their high theoretical energy density and good safety. However, owing to the high chemical compatibility requirements between metal fluoride cathode and the solid-state electrolyte (SSE), developing an adaptable SSE film with comprehensive properties is particularly challenging. Herein, a class of ionic liquid (IL) reinforced oxide SSE films was proposed. Among them, the combination of Li1.5Al0.5Ge1.5(PO4)3 (LAGP) oxide SSE and EMIM-based IL (LAGP-EMIM) exhibits good flame-retardant properties, exceptional air stability, high ionic conductivity and excellent chemical stability. The introduction of ILs can increase the ion transport channels in SSEs and render the usage of dry-process, well addressing the contradiction between the flexibility and ionic conductivity of oxide films. The thickness of LAGP-EMIM films is 59 μm and they show the highest ionic conductivity of 1.05 mS cm−1 among the NaSICON-type oxide-based SSE films till now. In addition, it can be stably matched with the conversion metal fluoride cathodes such as FeF3 and CuF2 to construct semi-solid-state batteries, delivering high initial discharge capacity of 820.2 and 539.6 mAh g−1, respectively. The present work shed new insight into designing the composite electrolytes toward the next-generation solid state conversion batteries.

Eco-innovation in energy: Solid degradation kinetics of rejected red macroalgae (Kappaphycopsis cottonii) for bio-oil and biochar production

In the pursuit of renewable energy sources, biomass conversion into biofuels has garnered attention as a sustainable alternative to fossil fuels. This research focuses on the pyrolytic conversion of red macroalgae, specifically rejected Kappaphycus cottonii, an underutilized biomass in Indonesia, into valuable bio-energy carriers, while analyzing the solid degradation kinetics involved. The dried K. cottonii underwent slow pyrolysis at varying temperatures (400–600 °C) and time intervals (10–50 min). The impact of these variables on the yield of bio-oil and biochar, alongside the thermogravimetric profiles indicating mass loss, was thoroughly assessed. The study also explores the chemical kinetics of the decomposition process, utilizing the first-order reaction model to analyze the solid biomass conversion rate, activation energy, and frequency factor. Key findings demonstrate that the optimal pyrolysis temperature for maximizing bio-oil yield was precisely 500 °C, beyond which thermal cracking led to yield reductions. Reaction times also greatly affect yield, highlighting the importance of optimized pyrolysis conditions. The determined activation energy and frequency factor, based on the Arrhenius equation, highlighted K. cottonii's lower decomposition energy barrier relative to terrestrial biomass. This distinction is largely ascribed to its unique chemical makeup, notably a lower lignin content, positioning K. cottonii as an advantageous feedstock for biofuel production through pyrolysis.

Synergistic Coupling of Sulfide Electrolyte and Integrated 3D FeS2 Electrode Toward Long‐Cycling All‐Solid‐State Lithium Batteries

FeS2 cathode is promising for all‐solid‐state lithium batteries due to its ultra‐high capacity, low cost, and environmental friendliness. However, the poor performances, induced by limited electrode‐electrolyte interface, severe volume expansion, and polysulfide shuttle, hinder the application of FeS2 in all‐solid‐state lithium batteries. Herein, an integrated 3D FeS2 electrode with full infiltration of Li6PS5Cl sulfide electrolytes is designed to address these challenges. Such a 3D integrated design not only achieves intimate and maximized interfacial contact between electrode and sulfide electrolytes, but also effectively buffers the inner volume change of FeS2 and completely eliminates the polysulfide shuttle through direct solid–solid conversion of Li2S/S. Besides, the vertical 3D arrays guarantee direct electron transport channels and horizontally shortened ion diffusion paths, endowing the integrated electrode with a remarkably reduced interfacial impedance and enhanced reaction kinetics. Benefiting from these synergies, the integrated all‐solid‐state lithium battery exhibits the largest reversible capacity (667 mAh g−1), best rate performance, and highest capacity retention of 82% over 500 cycles at 0.1 C compared to both a liquid battery and non‐integrated all‐solid‐state lithium battery. The cycling performance is among the best reported for FeS2‐based all‐solid‐state lithium batteries. This work presents an innovative synergistic strategy for designing long‐cycling high‐energy all‐solid‐state lithium batteries, which can be readily applied to other battery systems, such as lithium‐sulfur batteries.

Approaching high rate All-Solid-State Lithium-Sulfur batteries via promoted sulfur conversion with nickel oxide nanoparticle electrocatalyst

All-solid-state lithium-sulfur battery (ASLSB) is deemed a promising next-generation energy storage device owing to its combination of high theoretical specific energy (2600 Wh kg−1) derived from the sulfur active material, and exceptional safety characteristics and the ability to suppress the polysulfide shuttle effect through the use of solid electrolyte (SE). However, the low electronic and ionic conductivity of sulfur, coupled with the poor solid–solid interfacial contact inherent in all-solid-state configuration, has resulted in poor electrochemical performance. Herein, NiO electrocatalyst supported on N-doped sites of super-p was synthesized and incorporated as a carbon additive in the composite cathode of the ASLSB. The direct growth of nanosized NiO electrocatalyst on the N-doped sites of super-p ensures facile electron transfer to the electrocatalyst surface, while maximizing the electrocatalyst’s surface area. As a result, the overpotential during charging and discharging of the ASLSB was significantly reduced, as assessed through galvanostatic intermittent titration technique and cyclic voltammetry, indicating enhanced redox conversion of sulfur. Furthermore, the Li6PS5Cl sulfide SE induces solid–solid conversion of sulfur, eliminating the dissolution issue of polysulfide intermediates and ensuring good cycle performance. The assembled ASLSB exhibits a high reversible capacity of 1845 mAh g−1 at 0.05C at room temperature and enhanced rate capability at high C-rates, operated at 60 °C. Even at a substantially high sulfur loading level of 6.65 mg cm−2, a maximum areal capacity of 9.48 mAh cm−2 was achieved at room temperature, highlighting the important role of electrocatalyst in realizing high performance ASLSBs.

Thermal degradation of emerging pollutants in municipal solid wastes and agro wastes: effectiveness of catalysts and pretreatment for the conversion of value added products

In this study, emerging soil pollutants in the form of municipal solid waste (MSW) and agricultural waste were converted into biofuel via thermal degradation process. Among various waste-to-energy conversion processes, the pyrolysis of biomass is considered the most significant due to its maximum biofuel yield than other conversion techniques. Individual and co-pyrolysis of MSW and sugarcane residue (SR) as well as its treated variant (TSR) were performed in a lab-setup fixed-bed reactor with and without catalyst. The effect of acid pretreatment and catalytic effects on the pyrolysis process was assessed in terms of product yields and characterization. The acidic pretreatment of SR and catalyst in the pyrolysis process alters the process yield and its composition. The maximum oil yield of 50.5 wt% was achieved by catalytic co-pyrolysis of MSW + TSR + HZSM5, whereas the maximum gas yield of 38.1 wt% was achieved by catalytic co-pyrolysis of MSW + SR + HZSM5. This suggests that intrinsic minerals present in the biomass and MSW, particularly alkali and alkaline earth metals, have a catalytic effect on the devolatilization of organic material and the char cracking event. The pretreatment of biomass showed considerable improvement in the properties of the produced pyrolysis oil and char. Compared to the pyrolysis oil and char obtained from MSW + SR, the oil and char obtained from MSW + TSR + HZSM5 showed a small increment in their heating values. Pretreatment and the catalytic co-pyrolysis process influenced the structure of the pyrolysis oils, increasing the production of phenolic compounds and aromatic hydrocarbons. The amount of gas components in pyrolysis gas, such as CH4, CO2, and CO also changed more according to the feedstock used for the process. Overall, the HZSM-5 catalyst and co-pyrolysis of MSW with pretreated SR enhanced the pyrolysis conversion of waste municipal solids and agricultural wastes into energy-rich products.

A multi-scale experimental study on calcium-looping for thermochemical energy storage using the CO2 captured from power generation systems

The reversible carbonation/calcination reaction of calcium-rich particles (i.e., so-called calcium-looping), whether in an open loop configuration or in a closed cycle, has attracted significant attention in recent years for utility-scale thermochemical energy storage. The calcium-looping process and its variants can be used in conjunction with solid fuel-based conversion systems (e.g., combustors, gasifiers, pyrolysers, etc.) to store thermal energy in chemical form using the CO2 captured from the flue gas streams of these systems with CO2 concentrations typically ranging between 5 and 20 vol%. The calcium-looping-based processes, however, are very much scale dependant. What we know today about the application of the calcium-looping-based processes for thermochemical energy storage is largely based on small-scale experiments reported in the open literature. A multi-scale study was therefore conducted over that past four years to address this shortcoming by conducting a series of complementary experiments at instrument-scale (e.g., thermogravimetric analysers “TGA”), bench-scale, laboratory-scale, and pilot-scale.It was found that the results at different scales were not linearly correlated. For instance, while the calcination and carbonation temperatures had an impact on the reactivities of the calcium-rich particles, the extent of the impact was different at the instrument-scale (e.g., TGA), bench-scale, laboratory-scale, and pilot-scale. The differences between instrument-scale results and those of other scales are largely assigned to the absence of diffusional limitations for the transport of heat and mass at instrument-scale. Diffusional limitations, however, depend on the size and volume of a given system and as such underpin the discrepancies that we have seen among the experimental data collected at the bench, laboratory, and pilot-scales. For example, in our study the low calcination and carbonation temperatures typically resulted in higher reactivities at bench and laboratory-scales while the reactivity of calcium-rich particles at the pilot-scale remained largely unaffected by the calcination and carbonation temperature. Also, the extent of the deactivation of calcium-rich particles over the first few calcium-looping cycles differed at bench, laboratory, and pilot-scales. Hence, any industrial scale use of calcium-looping-based processes for thermochemical energy storage must be backed up by multi-scale studies like that reported here so that the scaling effects are well understood, and proper mitigation measures are implemented.

Transitioning towards circular economy through municipal solid waste analysis and characterisation using SowaCLINK software

Municipal solid waste constitutes environmental challenges globally, especially in developing countries, due to increasing waste generation, population growth, inadequate infrastructure, lack of data and poor planning. This study aims to conduct a comprehensive waste audit on the municipal solid waste generated in Aba, a metropolis in southeastern Nigeria. Aba is a commercial city considered the messiest because of the massive municipal solid waste generation and poor management. The study investigated the energy potential and waste regeneration. Municipal solid waste data was sought to provide insight into the quantity and composition of municipal solid waste. The methodology was site-based, in line with the standard test method for determining unprocessed municipal solid waste (ASTM-D5231-92) and SowaCLINK software, a computer-based environmental application, was used for characterization. Linear extrapolation was adopted to quantify the rate of municipal solid waste generated. The geometric mean was applied to forecast the area’s population for a 10-year design period. The chemical elements of the characterized municipal solid waste were utilized based on the ASTM-D5291 standard for municipal solid waste thermochemical conversion, and the high and low heating values were analyzed. The outcomes provided energy recovery potential, the electrical power potential, and the power to the grid of electrical power of the municipal solid waste. The results obtained were 0.7813 kg/p/d and 490,268 t/y for a population of 1,719,185 persons. The percentage of the municipal solid waste components with energy potential was 71%, comprising 48% combustible and 23% organic components on average. The high heating value computed was 176.5 MJ/kg, and the low heating value was 14 MJ/kg. The energy recovery potential was 3,709,463 MWh, the electrical power potential was 38,680 MW, and the power to the grid was 26.1 MW daily. The research reveals a promising direction in transitioning from the linear economy of municipal solid waste management toward implementing an integrated sustainable municipal solid waste management based on the circular economy model. The study recommends adopting detailed steps to proffer solutions to the environmental challenges associated with municipal solid waste in most low-middle-income countries to achieve sustainable municipal solid waste management while generating electricity and bio-fertilizers through incineration and anaerobic digestion.