Solid Residue Research Articles

DELIGNIFICATION OF OIL PALM EMPTY FRUIT BUNCHES USING DEEP EUTECTIC SOLVENT IN PRESSURIZED REACTOR

Although lignin from oil palm empty fruit bunches (OPEFB) is a sustainable bioresource with several value-added uses, it is still difficult to extract lignin from lignocellulosic biomass economically. Lignin fractions are required for high-value applications and subsequently increase the feasibility of lignocellulosic biorefineries. Besides, the remaining cellulose could be further valorized into various chemical products. In this study, the delignification efficiency of OPEFB under inert and pressurized conditions has been studied as an effective pretreatment method for OPEFB. The optimal conditions of the high-pressure reactor to remove lignin from OPEFB were determined to be 80 °C at 30 bars with the presence of deep eutectic solvents (DES). It was identified that pressure affects the removal of lignin with the least amount of structural breakdown and the digestibility of cellulose. The effective removal of lignin from the OPEFB was established under mild conditions employing an inert nitrogen gas pressurized system. This work selectively removes lignin from the OPEFB of palm oil biomass plants using DES under mild extraction conditions. Solid residues were characterized by using FTIR, SEM, TGA, and XRD to investigate fractions under various reaction conditions, such as removal temperature, time, and pressure. The thermal stability of lignin was determined by TGA. In this study, 36.68% of lignin was removed under optimum pressure conditions at the lowest process temperature of 80 °C to determine how these factors influence the efficiency of lignin extraction in a high-pressure reactor.

Hybrid Organic-Inorganic Copper and Cobalt Complexes for Antimicrobial Potential Applications

Background/Aims: The naturally occurring phenolic chemical curcumin (CUR), which was derived from the Curcuma longa plant, has a variety of biological actions, including anti-inflammatory, antimicrobial, antioxidant, and anticancer activities. Curcumin is known for its restricted bioavailability due to its hydrophobicity, poor intestinal absorption, and quick metabolism. To boost the biological effects of these bioactive molecules, it is necessary to raise both their bioavailability and their solubility in water. Aim: The aim of this study is to synthesize and characterize hybrid organic-inorganic complexes of copper and cobalt, and to evaluate their antimicrobial potential against a range of pathogenic microorganisms. Methods: The synthesis of metal curcumin complexes (Cu-CUR and Co-CUR) was achieved by mixing curcumin with copper acetate monohydrate. The solid residue was isolated, filtered, and dried in an oven. X-ray diffraction analysis was used to identify the structure and phase of the prepared samples. FTIR spectra were recorded using a Shimadzu 2200 module. The antimicrobial activity of the prepared complexes was evaluated against four bacterial strains and two Candida species. The chemical materials were dissolved in DMSO to a final concentration of 20%, and the plates were incubated at 37°C for 24 hours. The results showed that the prepared complexes had antimicrobial activity against the tested microorganisms. Results: The study compared the Powder X-ray diffraction (XRD) patterns of prepared copper and cobalt complexes to pure curcumin, revealing new, isostructural complexes. The FTIR analysis showed that the Cu-CUR and Co-CUR complexes varied in their inhibitory effect against microorganisms, with Co-CUR being more effective. The results are consistent with previous studies showing the cobalt-curcumin complex was effective against various bacterial genera, with inhibition activity varying depending on the species and strains of microorganisms. Conclusion: Copper and cobalt curcumin complexes, synthesized at room temperature, exhibit high crystallinity and antimicrobial activity. Co-CUR, with its superior antibacterial potential, outperforms pure curcumin in inhibiting microbes. Further investigation is needed to understand their interaction mechanisms with bacteria and fungi.

Heterogeneous solid residue from macadamia nut processing as viable feedstock for high-temperature gasification

This study delves into the intriguing prospect of concurrently utilizing macadamia husk and nutshell for biomass gasification, aiming to generate sustainable energy. By scrutinizing their physicochemical properties such as thermal behaviors, char conversion kinetics, and syngas properties we unveiled an intriguing revelation. The fusion of these residues creates an apt feedstock for biomass batch-gasification in industrial settings. This resultant blend inherits distinctive traits from its constituent parts, profoundly influencing gasification reactivity and fostering heightened char conversion efficiency and stability. Spanning 2165 s, this process exhibited commendable control. Furthermore, the residue amalgamation consistently yields an average syngas flow rate of 0.00136 [mol (g minute)−1], predominantly composed of CO at 0.00097 [mol (g minute)−1], constituting over 71 % of the syngas. These findings underscore the potential of merging these residues to optimize the conversion process and bolster resource availability, thus propelling advancements in waste-free energy production and sustainable energy technologies.

A Sustainable Recycling Approach to Regenerate Graphite from Industrially Sourced Failed Anodes

Recycling graphite from Li-ion battery (LIB) waste plays an important role in increasing the accessibility of graphite resources and sustainable recovery. This presentation describes our work to purify graphite from failed (i.e., out-of-specification) anodes in LIB manufacturing by focusing on the most common contaminant: copper, used as the current collector in LIB anodes.A new, three-step scalable and environmentally friendly approach was used to provide a cost-effective and sustainable method in industrial settings to recycle failed anodes during the early stages of battery manufacturing.The study aimed to understand the differences between new, battery-grade graphite and recycled graphite from anode production waste. In particular, focus was placed on the effect of metallic Cu residues on electrochemical performance. The efficiency of Cu removal from graphite was quantified by Microwave Plasma – Atomic Emission Spectroscopy (MP-AES) analysis of leachates. The following experimental parameters were studied to maximize Cu leaching efficiency: solid-to-liquid ratio, temperature, acid concentration, time and stirring speed.The surface morphology and elemental composition of leached and thermally treated purified graphite were analysed by Scanning Electron Microscopy – Energy Dispersive Spectroscopy (SEM-EDS) and Laser Induced Breakdown Spectroscopy (LIBS). The specific surface area and crystallographic parameters were measured by Braunauer–Emmett–Teller Analysis (BET) and X-Ray Diffraction (XRD), respectively. The electrochemical performance was evaluated by galvanostatic cycling with potential limitation versus Li+/Li. These five techniques were carried out on the solid residues after each stage of the regeneration procedure. The results were compared with battery-grade graphite to assess the effectiveness of our sustainable recycling approach to reuse graphite from failed anodes in LIBs.

Role of Side Reaction Involving PbOx in Soluble Lead Redox Flow Battery: Effect on Cyclability

Soluble lead redox flow battery (SLRFB) has been an active subject of investigation in the past two decades because of its high energy efficiency (~70%) and charge efficiency (~90%) [1]. During charging, Pb2+ ions deposit as solid lead dioxide (PbO2 ) on anode and solid lead (Pb) on cathode, respectively. These features permit a membrane-less single-compartment design, making SLRFB a cost-effective electrochemical energy storage device. Discharge occurs by electro-dissolution of these solids, regenerating the electrolyte. The limited cycle-life of SLRFB is its current deployment challenge (best achieved about 100 cycles [2]). The shedding of solid lead dioxide over cycling is an indirect irreversible loss of active material from the electrolyte, the reason for SLRFB’s limited cyclability.Mathematical models link the deposit formation and the two-step charging potential profile through a side reaction involving PbO and PbO2 [3-5]. Morphological changes in deposit during cycling have been reported and presented as an alternate justification to the two-step potential profile [6]. To clarify these, we tested the role and feasibility of re-oxidation of solid PbO on cycling under varied conditions using an in-house prepared Nafion membrane-divided cell. We show that the charging through side reaction does not occur without the availability of Pb2+ near the electrode. We also show that the observations are independent of the electrodes’ age, the amounts of PbO and PbO2 present, and the applied current density. We obtained FESEM images of anode after short re-charging in a single-compartment design. We observed the formation of a new phase, plausibly lead dioxide from Pb2+ ions, leaving the solid residue almost unaffected. These findings challenge the idea of charging sustained in part by the oxidation of PbO through the side reaction. The deposit, constituted by whisker-like particles (thickness~200 nm), appears weak and layered. Gas evolution reactions known to occur under the limited availability of Pb2+ ions may promote residue disintegration. These observations lead us to hypothesize that cycling leads to irrecoverable residue accumulation, which may negligibly participate in further re-oxidation through the side reaction. These cumulative effects, accompanied by formation of a new phase at every charging, appear to contribute significantly to restricting SLRFB to a short cycle-life. These features raise concerns about the prevailing hypotheses about SLRFB dynamics and suggest need for strict design and operational controls to avoid residue buildup.

Unlocking Value from Municipal Solid Waste Incineration Ash: Electrochemical and Chemical Approaches for Materials Recovery

Nowadays, in the U.S. more than 6.6 million tons of hazardous solid residue, called municipal solid waste incineration (MSWI) ash is annually generated in waste-to-energy (WTE) plants for producing electricity and reducing landfill volume. This ash cannot be further utilized for beneficial applications, so it is mostly buried and has a negative value with the cost of a disposal fee. Moreover, the economics of MSWI is challenged by the decreasing cost of renewableelectricity. However, WSWI ash represents a unique opportunity for valuable element recovery, with the embodied value ranging from $100-400/tonne. We propose an electrochemical and chemical process for mining MSWI ash that utilizes electricity from the WTE plant toelectrolytically produce acid and base streams for materials recovery and refining. We establish a sequential process of electrochemical extraction and chemical precipitation, and successfully recover Cu, Pb, Zn, Mg, Ca, Fe, Al, with a purified silica co-product. Recovery of >90% of the targeted elements at purities >90% is demonstrated. The industry-scale technoeconomic analysis shows our proposed technology will realize the possibility of extracting the embodied mineral value with net positive returns that significantly exceed the combined value of WTE electricity sales and landfilling cost.

Assessing Full Stomach Prevalence with Ultrasound Following Preoperative Fasting in Diabetic Patients with Dysautonomia: A Comparative Observational Study.

Traditionally, diabetics have been considered patients with a high risk of aspiration due to having delayed gastric emptying; However, the evidence concerning residual gastric volume (GV) in fasting diabetic patients is inconsistent. This study aimed to compare the fasting GV of diabetic patients with or without dysautonomia with control patients scheduled for elective surgery using gastric ultrasound. This bicentric prospective single-blinded case-control study was conducted at 2 university hospitals in Spain. Patients aged over 18 years, classified as American Society of Anesthesiologists (ASA) physical statuses I to III and having similar fasting statuses, were included in the study. The primary outcome was to compare the prevalence of risk stomach using the Perlas gastric content grading scale evaluated by ultrasound in the 3 groups. Secondary outcomes included the measurement of cross-sectional area (CSA) and GV in the right lateral decubitus (RLD) position, as well as the prevalence of solid gastric residue. A total of 289 patients were recruited for the study, comprising 145 diabetic patients (83 of whom had dysautonomia) and 144 patients in the control group. The percentage of patients classified as Perlas grade 2 was 13.2% in the control group, 16.1% in diabetic patients without dysautonomia, and 22.9% in diabetic patients with dysautonomia (P = .31). Antral CSA was significantly higher in diabetic patients with dysautonomia (6.5 [4.8-8.4]) compared to the control group (5.4 [4.0-7.2]; P = .04). However, no significant differences were observed between groups in residual GV. Among diabetic patients with dysautonomia, 12% exhibited solid gastric residue, which was twice the percentage observed in diabetic patients without dysautonomia (4.8%) and 3 times higher than that in the control group (3.5%; P = .03). The presence of dysautonomia was associated with an increased odds ratio of solid gastric residue (odds ratio [OR], 3.37; 95% confidence interval [CI], 1.28-8.87; P = .01) after adjusting for confounding factors. This study offers insights into the relationship between dysautonomia in patients with diabetes mellitus and the presence of full stomach, underscoring the significance of preoperative gastric ultrasound evaluation in managing perioperative risks in this population.

Biofuel from wastewater-grown microalgae: A biorefinery approach using hydrothermal liquefaction and catalyst upgrading

Third-generation biofuels from microalgae are becoming necessary for sustainable energy. In this context, this study explores the hydrothermal liquefaction (HTL) of microalgae biomass grown in wastewater, consisting of 30% Chlorella vulgaris, 69% Tetradesmus obliquus, and 1% cyanobacteria Limnothrix planctonica, and the subsequent upgrading of the produced bio-oil. The novelty of the work lies in integrating microalgae cultivation in wastewater with HTL in a biorefinery approach, enhanced using a catalyst to upgrade the bio-oil. Different temperatures (300, 325, and 350 °C) and reaction times (15, 30, and 45 min) were tested. The bio-oil upgrading occurred with a Cobalt-Molybdenum (CoMo) catalyst for 1 h at 375 °C. Post-HTL, although the hydrogen-to-carbon (H/C) ratio decreased from 1.70 to 1.38–1.60, the oxygen-to-carbon (O/C) ratio also decreased from 0.39 to 0.079–0.104, and the higher heating value increased from 20.6 to 36.4–38.3 MJ kg−1. Palmitic acid was the main component in all bio-oil samples. The highest bio-oil yield was at 300 °C for 30 min (23.4%). Upgrading increased long-chain hydrocarbons like heptadecane (5%), indicating biofuel potential, though nitrogenous compounds such as hexadecanenitrile suggest a need for further hydrodenitrogenation. Aqueous phase, solid residues, and gas from HTL can be used for applications such as biomass cultivation, bio-hydrogen, valuable chemicals, and materials like carbon composites and cement additives, promoting a circular economy. The study underscores the potential of microalgae-derived bio-oil as sustainable biofuel, although further refinement is needed to meet current fuel standards.

Transformation of Cu2O into Metallic Copper within Matrix of Carboxylic Cation Exchangers: Synthesis and Thermogravimetric Studies of Novel Composite Materials.

In order to systematize and expand knowledge about copper-containing composite materials as hybrid ion exchangers, in this study, fine metallic copper particles were dispersed within the matrix of a carboxyl cation exchanger (CCE) with a macroporous and gel-type structure thanks to the reduction of Cu2O particles precipitated within the matrix earlier. It was possible to introduce as much as 22.0 wt% Cu0 into a gel-type polymeric carrier (G/H#Cu) when an ascorbic acid solution was used to act as a reducer of Cu2O and a reagent transforming the functional groups from Na+ into the H+ form. The extremely high shrinkage of the porous skeleton containing -COOH groups (in a wet and also dry state) and its limited affinity for water protected the copper from oxidation without the use of special conditions. When macroporous CCE was used as a host material, the composite material (M/H#Cu) contained 18.5 wt% Cu, and copper particles were identified inside the resin beads, but not on their surface where Cu2+ ions appeared during drying. Thermal analysis in an air atmosphere and under N2 showed that dispersing metallic copper within the resin matrix accelerated its decomposition in both media, whereby M/H#Cu decomposed faster than G/H#Cu. It was found that G/H#Cu contained 6.0% bounded water, less than M/H#Cu (7.5%), and that the solid residue after combustion of G/H#Cu and M/H#Cu was CuO (26.28% and 22.80%), while after pyrolysis the solid residue (39.35% and 26.23%) was a mixture of carbon (50%) and metallic copper (50%). The presented composite materials thanks to the antimicrobial, catalytic, reducing, deoxygenating and hydrophobic properties of metallic copper can be used for point-of-use and column water/wastewater treatment systems.

Starch Recovery Process from the Tiger Nut Horchata Processing Waste

AbstractTiger nut horchata solid residue (HSR) has high starch content (about 23%, dry basis) that can be recovered to valorise this waste, together with other valuable components, such as oil, fibres, or phenolic compounds. In this study, a chemical-free, sustainable process was proposed to obtain starch with good yield and purity. This consists of a high-speed homogenisation step with distilled water, followed by filtration and phase separation by density in the slurry to obtain a starch-rich sediment that can be isolated by decantation. Five minutes of homogenisation at 10,200 rpm allows for obtaining 14.5 g of starch powder per 100 g of dried HSR, with a purity of about 85% and WI of 94.97. Applying 1 washing cycle to the filtering residue increased the starch powder yield up to 17 g/100 dried HSR, without notable losses in starch purity, whereas centrifugation at 15,000 g for 1 h in the phase separation step highly reduced separation time, increasing starch purity up to 92%. Thus, it was possible to recover up to 70% of the starch present in the HSR. The obtained starch had similar morphological characteristics, crystallinity degree, and gelatinisation behaviour to that present in the tiger nut tubers, exhibiting similar thermal stability to that reported for other native starches. Therefore, HSR can be used as a starch source for different uses.

Factors influencing demulsification of refinery oily sludge via ultrasonic treatment

Ultrasonic demulsification treatment is essential to dehydrate refinery sludge with complex composition, high water content, and demulsification difficulty. Herein, the influencing factors and the demulsification mechanism are studied in oily sludge treatment. The effects of initial temperature, ultrasonic amplitude, and time, as well as a diversity of additives on the ultrasonic dehydration rate of oily sludge demulsification, are investigated. The optimal demulsification conditions are confirmed (temperature: 20 °C, ultrasonic amplitude: 100 %, and ultrasonic time: 5 min), based on the effectiveness and economy of dehydration. The combined ultrasonication and pyrolysis of the solid residue of sludge shows a dehydration rate of 60.49 %, beneficial for the green transformation and utilization of subsequent demulsification products. Moreover, the mechanism of ultrasonic emulsification is proposed, as well. This work provides an important reference for the subsequent resource utilization of oily sludge in the industry.

Unravelling the complexity of hemicellulose pyrolysis: Quantitative and detailed product speciation for xylan and glucomannan in TGA and fixed bed reactor

For the first time, the complete characterization of the pyrolysis of key biomass components – xylan (representative of pentose-based hardwood hemicellulose) and glucomannan (representative of hexose-based softwood hemicellulose) – is herein obtained by applying a novel methodology based on TGA (thermogravimetric analysis), previously developed for cellulose. Data on devolatilization rates, onset temperatures and detailed quantification of the mass yield of ∼ 50 products in the gas, liquid, solid phase were achieved simultaneously, with closure of mass balance, thus providing unique kinetic information. Pyrolysis tests were also carried out in a fixed bed reactor to explore larger scales and validate the TGA-based approach. At both scales, combinations of different analytical techniques (online MS, offline GC-FID/MS, Karl Fischer titration) and sampling protocols (cold condenser, sorbent traps, vapour syringes, gas bags) were tuned to achieve closure of mass balances and rigorous product speciation.While the pyrolysis of cellulose – chosen as reference system − maximized the bio-oil production (mostly levoglucosan), the pyrolysis of xylan resulted into an even distribution among solid, liquid and gas phases, with condensable oxygenates spanning homogeneously in the C1-C9 range. Interestingly, glucomannan showed an intermediate behaviour between cellulose and xylan, mirroring its intermediate chemical structure. Raman and oxidation analyses on the collected char samples showed that the solid residuals from hemicelluloses were less ordered and richer in ashes than those from cellulose.The predictions of recent lumped kinetic models were used to benchmark the new datasets against the prior art on hemicellulose pyrolysis; the richness and comprehensiveness of the new information clearly emerge and pave the pathway to the de-bottlenecking of kinetic modelling.

In-Line Thermal Desorption and Dielectric Barrier Discharge Ionization for Rapid Mass Spectrometry Detection of Explosives.

Thermal desorption (TD) of wipe-based samples was coupled with an in-line dielectric barrier discharge ionization (DBDI) source and rugged compact time-of-flight mass spectrometer (MS) for the detection of explosives, propellants, and postblast debris. The chromatography-free TD-DBDI-MS platform enabled rapid and sensitive detection of organic nitramine, nitrate ester, and nitroaromatic explosives as well as black powder and black powder substitute propellants. Parametric investigations characterized the response to TD temperature and optimized DBDI voltage, aerodynamically assisted entrainment, and fragmentation through in-source collision induced dissociation (isCID). Excess nitrate generated by the DBDI source yielded predominantly nitrate-adduct formation. Subnanogram sensitivities were demonstrated for all explosives investigated, except for nitroglycerin, specifically due to its volatility. Further, most analytes/explosives exhibited tens of picograms sensitivities. The platform also demonstrated the detection of propellant and military explosives from postblast debris. The TD-DBDI-MS system performed well without the need for aerodynamically assisted entrainment (and the associated rough pump), which along with requiring no additional gases (i.e., N2 or He) or solvents, aid in potential field deployment. The ease of TD-DBDI attachment and removal added trace solid or liquid residue detection to the rugged mass spectrometer, designed primarily for the analysis of volatile organic and inorganic compounds.

A two-stage strategy combining vermicomposting and membrane-covered aerobic composting to achieve value-added recycling of kitchen waste solid residues

A two-stage strategy combining vermicomposting and membrane-covered aerobic composting to achieve value-added recycling of kitchen waste solid residues

Life cycle assessment of recycling metallised food packaging plastics using mechanical, thermal and chemical processes

Single treatment of metallised food packaging plastics waste (MFPW) has shown disappointing results with recycling rate <20 % due to its complex structure consisting of 10 % aluminium (Al) and 90 % mixed plastic films made of PE, PP, PS, PET, etc. Besides, it is generating many emissions and residues that must be landfilled making it difficult to integrate them into the circular economy. Therefore, a multi-stage recycling (MSR) approach has recently been developed using several sequential mechanical, thermal and chemical processes to recover energy and Al from MFPW with additional revenue for recycling plant operators. The thermal treatment helps to decompose the plastic fraction into wax or oil, gaseous, and solid residue (SR) composed of Al and coal, while the mechanical process can be used as a pre-treatment of MFPW feedstock and SR. Finally, the chemical treatment (leaching and functionalization) can be used to extract Al from SR and to refine coal into carbon microparticles (CPs), respectively. In order to investigate the environmental performance of the proposed MSR system, this research was developed. The investigation was performed using SimaPro life cycle analysis (LCA) tool according to ISO 14040/44 Standards and the impact assessment method is ReCiPe 2016. Five different scenarios were proposed in the constructed LCA layout, namely, conversion of MFPW to a) wax and gas (pyrolysis), b) wax, gas, and aluminium chloride (AlCl₃) (pyrolysis and leaching), c) wax, gas, AlCl₃, and CPs (pyrolysis, leaching, and functionalization), and d) oil, gas, AlCl₃, and CPs (catalytic pyrolysis, leaching, and functionalization). Besides, the oil produced from catalytic pyrolysis is used for generation of electricity (scenario e). The results showed that wax and gas recovery scenario (a) has better environmental potential and environmental benefits compared to incineration practice. The results did not change much after extraction of Al and CPs (scenario b, c), with a few increasing by 2–4% in the total score. While a lot of environmental burdens from upgrading and utilization (Scenario d, e) were recorded, reaching 79 % due to the huge amount of the catalyst was used. Thus, MSR systems have bigger environmental benefits, however, the chemical and catalytic processes still need to be further improved to reduce the effect of terrestrial acidification.

Solid residues after gasification of agricultural residues as scalable and economical CO2 adsorption materials

Economical CO2 adsorbents are gaining significant attention as viable solutions to combat climate change. This research assessed the CO2 adsorption potential of solid residues following the gasification of bagasse (SR-Bagasse), bamboo (SR-Bamboo), and rice husk (SR-Rice husk) in various systems in Vietnam and Cambodia. Among these residues, SR-Bagasse showed the highest CO2 adsorption capacity, followed by SR-Bamboo, while SR-Rice husk exhibited moderate performance. The CO2 adsorption capacity at 25 °C with 100 % CO2 flow varied from 6 % to 9.5 % of the adsorbent's weight. Under flue gas conditions (15 % CO2 and 85 % N2), the adsorption capacity ranged from 2 % to 5 %. Additionally, these chars demonstrated significant recyclability with 90 % of initial adsorption capacity retained after 30 cycles, making them comparable to several advanced CO2 adsorbents studied previously. The highest performance of SR-Bagasse could be attributed to its substantial microporous and ultra-microporous volumes, with micropores serving as both CO2 adsorption sites and conduits to ultra-micropores. This study's findings emphasize the potential for integrating energy production with the development of economical and scalable CO2 adsorbents for industrial use.

Adsorption of methane by modified-biochar aiming to improve the gaseous fuels storage/transport capacity: process evaluation and modeling.

The CH4 storage by adsorption on activated carbons for natural gas handling has gained interest due to the appearance of lightweight materials with large surface areas and pore volumes. Consequently, kinetic parameters estimation of the adsorptive process can play a crucial role in understanding and scaling up the system. Concerning its versatility, banana peel (BP) is a biomass with potential for obtaining different products, such as biochar, a solid residue from the biomass' thermal decomposition of difficult disposal, where through an activation process, the material porous features are taken advantage to application as adsorbent of gaseous substances. This research reported data for the CH4 adsorption kinetic modeling by biochar from BP pyrolysis. The activated biochar textural characterization showed particles with fine mesoporous structure (pore diameter ranging between 29.39 and 55.62Å). Adsorption kinetic analysis indicated that a modified pseudo-first-order model was the most suitable to represent the experimental data, with equilibrium adsorption of 28mgg-1 for the samples activated with 20.0% vol wt.-1 of H3PO4 and pyrolysis at 500°C. The equilibrium constant was consistent with the Freundlich isotherm model, suggesting a physisorption mechanism, and led to a non-ideal, reversible, and not limited to monolayer CH4 adsorption.

Comparative analysis of bioenergy and mycoprotein production from apple pomace: Strategies for enhancement and environmental benefits

Apple pomace constitutes a major waste stream of the food processing industry that is characterized by high concentrations of free sugars and structural carbohydrates. This study comparatively explored alternative apple pomace valorization strategies. To this regard, the integration of hydrothermal and organic acid pretreatment as a strategy to enhance anaerobic digestion biomethane yield and alternative production of mycoprotein as a valuable secondary product via the use of Aspergillus oryzae and Neurospora intermedia edible fungi were investigated. In scenario 1, both pretreatment liquors and solid residues underwent anaerobic digestion to produce biomethane. In scenario 2, pretreatment liquors and solid residues underwent fungal cultivation and anaerobic digestion, respectively. Additionally, to optimize bioenergy yield and minimize wastewater generation in scenario 2, the fungal growth effluent was also subjected to anaerobic digestion. In scenario 1, employing methane for transportation showed the potential to decrease GHG by 314.8 kt CO2 eq, translating to US$72.4 million in social cost savings. Similarly, in scenario 2, replacing edible fungal biomass in the food market could lead to a substantial reduction in emissions by 824.2 kt CO2 eq and a corresponding US$227.0 million in social cost savings.

Study on recirculating aquaculture system (RAS) in organic fish production

Abstract The growth of conventional aquaculture has created environmental issues due to excessive feeding, low dissolved oxygen level etc into the water body. Organic aquaculture is a recent development as a solution to these issues. It is a clean alternative to reduce pollution and to produce safer consumable food. In the past few decades, recirculating aquaculture systems (RAS) were introduced to maintain pond water quality through lesser water exchange, by focusing on water reuse after treatment. In this study, the technical viability of RAS was analyzed for introduction in organic aquaculture systems. Indian major carps (IMCs) were cultured through conventional methods in the three tanks of conventional system, while the same species was grown organically in another three tanks in organic system. The stocking density and physical conditions were kept same for both cultured systems. The RAS consisted of fish culture tank with an average volume of each tank was 165 m3, a screen filter, foam fractionator and trickling filter. The various water quality parameters, i.e., solid size distribution in water, and removal efficiencies in biological treatment of both systems were compared. The present study, particle size distribution of solids in water body was measured by filtration, followed by weighing of dry residue solids. Pore sizes of 1000μ, 100μ, 20μ and 3μ were employed for filtration. For organic tanks, a majority of solids are of size between 1 mm and 100 μm. The larger sized particles (&gt; 30 μm) constitute nearly 70 % of the solids and the trait differs from the generalized conclusions of that a major part of sediments will be of sizes less than 20 μm. For the conventional tanks, majority of solids are of size between 3 mm and 20 μm and TAN shows higher removal efficiencies for effluents from organic system rather than conventional system. The results showed that organic aquaculture causes lesser pollution load per weight of fish. The particle size distribution of organic water was better compatible to screening and sedimentation than conventional water. Also the filtration efficiencies in nitrifying trickling filters of both water bodies were comparable, with that of organic water slightly on the higher side. Thus recirculating water treatment systems are introduced in organic aquaculture.

Performance evaluation of fracturing fluids in the presence of NaCl, CaCl2 and KCl as hydrate inhibitors for extremely low temperature stimulation applications

Naturally occurring gas hydrates are established as an abundant reserve of natural gas. Production initiatives raised challenges such as low production rate, freezing problems, water, and sand production along with geomechanical concerns. Recent studies suggest that fracturing the sediment can significantly improve the conductivity and productivity of such reserves. This study is an initiative to verify the suitability of conventionally used polymer (guar) for fracturing at extremely low temperatures along with the integration of widely available gas hydrate inhibitors for efficient stimulation. Established inhibitors such as NaCl, CaCl2 and KCl were introduced to linear and crosslinked gels to study their compatibility with the reference guar-based gels. The inhibitor integrated linear gel samples demonstrated similar performance trends to that of the reference gel establishing their compatibility with the polymer, whereas the inhibitor integrated crosslinked samples displayed deswelling nature. The low concentration inhibitor integrated linear gel samples performed superior to the reference gel whereas the high concentration sample inhibited the swelling performance of the polymer. Both the reference and inhibitor integrated linear gel samples gradually disintegrated after 48 h leaving behind soft cloudy residue, whereas the inhibitor integrated crosslinked samples rapidly released water and contracted into a solid residue which can cause serious flow related disruptions during operations and apparently damage the conductivity of the sediment for long term. This study delivers crucial understanding on how various salts interact with guar polymers at low temperatures and whether their presence can be a boon or bane during the design of a fracturing fluid.