ACS Sustainable Resource Management最新文献

This study developed a two-stage direct thermal contact (2sDTC) process to dewater fluid fine tailings (FFT) from oil sands tailings ponds integrated into ore processing/bitumen extraction plants. The integration aims to recover heat and water from FFT thermal dewatering, thereby reducing FFT storage and freshwater usage while maintaining plant energy efficiency. Employing air-fired natural gas combustion, the process initially involves direct contact between the combustion gas and sprayed FFT, yielding dried solids and steam-rich hot gas. This gas was then mixed with recycled pond effluent water, producing hot water by capturing heat and moisture from FFT dewatering. Case studies using HYSYS simulation assessed the integration feasibility for an extraction plant producing 200,000 barrels daily. Benefits include dewatering 3.36–3.94 million tonnes of FFT annually, conserving a freshwater equivalent to 0.2 barrels per barrel of oil produced. Importantly, these benefits incur no additional energy cost, as the integration eliminates the energy penalty and CO₂ emissions associated with FFT dewatering. Further enhancement using centrifuge-concentrated FFT with approximately 50 wt % solids, which remains pumpable as revealed by this study, increases annual dewatering capacity to 8.05–9.53 million tonnes of FFT, conserving 0.58 barrels per barrel of oil produced, with energy consumption limited to powering the centrifuge machinery.

The two-stage direct thermal contact (2sDTC) process and its integration reduces oil sands tailings stored in ponds, conserving freshwater and energy, crucial for sustainable resource extraction and environmental preservation.

Nanoparticles of n-AgBi₃S₅, n-Bi₂S₃, and n-n-AgBi₃S₅-Bi₂S₃ nanocomposite were synthesized by a facile one-pot hot chemical (90 °C) method using ethylene glycol as a medium without further calcination. The nanocomposite on exposure to natural sunlight exhibits significant and synergistic photocatalytic activity towards degradation of pollutant dye Rhodamine-B (Rh-B) in aqueous solution. The as-synthesized monoclinic AgBi₃S₅, orthorhombic Bi₂S₃, and their nanocomposite were identified and characterized by various spectroscopic, diffraction (XRD), and microscopic techniques. The UV-visible spectroscopic study reveals significant absorption of visible light and narrow band gaps/eV: 2.8 and 1.9 for synthesized Bi₂S₃ and AgBi₃S₅ respectively. The spectroscopically evaluated maximum % of degradation of Rh-B (99.9) and related high-rate constant (0.059 min^–1) were achieved within 25 min with 0.7 g/L AgBi₃S₅-Bi₂S₃ nanocomposite at pH 3. The radical trapping experiments reveal that both ^•O₂^– and ^•OH are almost equally involved in the degradation, while hole, h⁺ is the main initiator of the degradation as usual. Studies of the products of degradation reveal both de-ethylation and ring breaking of Rh-B, indicating simultaneous absorption of sunlight by it and the catalyst. The very high efficiency and synergistic effect of the nanocomposite might be due to either/both Z scheme/S scheme charge separation. The 95% retention of the photocatalytic activity by the 5th time used catalyst AgBi₃S₅-Bi₂S₃ signifies its superiority by auto surface improvement during a reaction.

The composites industry is now turning to a new sustainable material called a biobased epoxy vitrimer. This material is a great substitute for traditional petroleum-based thermosets, which are not recyclable and cause environmental pollution and CO₂ emissions. On the other hand, biobased epoxy vitrimers are a sustainable option due to their recyclability, reprocessability, and repairability properties. Recent research has emphasized developing biobased epoxy vitrimers derived from vegetable oil, lignin, vanillin, etc. The covalent adaptation networks and material properties of these epoxy vitrimers have also been explored. This review examines the current trends in used biobased epoxy vitrimer materials in several applications such as adhesives, coatings, shape memory, self-healing, and composites. The review aims to provide proper guidelines for the preparation of biobased epoxy vitrimers that can significantly contribute to the sustainable development of biobased vitrimer research.

Low-grade ores have received great attention from an economic and environmental perspective due to the shortage of high-grade manganese ore resources. However, it is worth mentioning that the final value of the recovery process must be cost-effective. The extracted Mn²⁺ ions from the low-grade manganese ore were purified and converted to the desired manganese salt which is used as a Mn²⁺ source for the synthesis of manganese sulfide nanostructures (MnS). The low-grade oxide ore was treated by reduction roasting using chemically pure sulfur as a reductant. Then, the roasted samples were subjected to selective leaching conditions to extract manganese (Mn). The effects of the roasting and leaching parameters on the leaching efficiencies of Mn and Fe are investigated. The Mn leaching efficiency of 90.67% is obtained under the optimized conditions, whereas the Fe leaching efficiency is <0.01%. Additionally, the electrocatalytic application towards the oxygen evolution reaction (OER) of the hydrothermally synthesized MnS was studied in 1 M KOH using nickel foam (NF) as the substrate. The MnS-NF electrode material exhibits an overpotential of 285 mV at a standard current density of 10 mA/cm² and a Tafel slope of 75 mV/dec, respectively.

Due to expanding seaweed-based industries and the growing popularity of seaweed biorefineries, there is an increasing opportunity for high-value applications of seaweed-extracted polysaccharides. One of the most fascinating applications for these biopolymers is in the field of agriculture, where they have been used as fertilizers, hydrogel/granules for slow release of urea, herbicides, insecticides, and water reservoirs to tackle drought-like situations. Polysaccharides, such as alginate, agar/agarose, ulvan, carrageenan, etc., have been used as such for a long time in multiple applications; however, their use in the development of hydrogels and subsequent utilization to deal with agricultural challenges like drought mitigation, to reduce chemicals leaching from fertilizers, or to lessen the harmful impacts of pesticides and increase crop yields, has recently gained a significant amount of interest from scientists. In this review article, we thoroughly discuss the technique generally utilized to extract polysaccharides from seaweeds, the structure, the gelation mechanism, and agricultural applications of various hydrogels, namely, alginate, agar/agarose, ulvan, and carrageenan. The impact of various bioadditives and surface modification techniques on the properties of polysaccharide-based hydrogels, such as water absorption/retention tendency, variation in fertilizers/pesticide releasing capability, etc., are discussed. Finally, the challenges along with some future possibilities are also discussed.

The exploration of underused seaweed-based sustainable hydrogels in agriculture will help to address water scarcity in arid regions while also mitigating adverse environmental impacts posed by synthetic agrigels.

The development of lighter, high-performance materials, such as composite materials, is in growing demand, especially in the automotive sector, but it generates significant waste. Therefore, the present study introduces thermoset composites of carbon fiber (CF) and epoxy resin (ER) as a material with great potential for achieving a maximum weight reduction in automotive vehicles. In this study, a thermal recycling route using both conventional oven and microwave oven pyrolysis to recover CF from CF/ER composite waste generated in the automotive sector was performed. Pyrolysis in a conventional oven under nitrogen with durations of 20, 45, and 60 min resulted in a 29.1% weight loss. Additionally, microwave oven pyrolysis was conducted under both nitrogen and oxidative atmospheres with durations ranging from 10 to 20 min, leading to a weight loss of 34.4% in a nitrogen atmosphere and 40.3% in an oxidative atmosphere. The recovered CF was characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), contact angle measurements, and tensile testing of the CF monofilaments. Thermal recycling using a microwave oven enabled the recovery of clean and intact CF without compromising its mechanical properties, facilitating its reuse in new applications and processing. Based on the results, thermal recycling using a microwave oven shows promise for CF recovery with low pyrolysis time, resulting in greater energy efficiency during thermal recycling.

The recovery of carbon fibers from structural composites is a sustainable alternative for producing new components, contributing to the circular economy and conserving mineral resources.

In order to estimate the ability of biochar to sequester carbon as part of greenhouse gas removal technology, there is a need for rapid and accessible estimations of biochar stability. This study employs a novel method using Fourier transform infrared spectroscopy (FTIR) to predict common stability indicators, namely H:C and O:C molar ratios. Biochars derived from barley straw were produced at temperatures from 150 to 700 °C. The greatest compositional changes of the biochars occurred between 200 and 400 °C. All biochars produced at ≥400 °C achieved H:C < 0.7 and O:C < 0.4, indicative of biochars suitable for soil application. Regression models were built using FTIR data to predict H:C and O:C molar ratios. The H:C model produced a coefficient of determination (R ²) of 0.99, mean absolute percentage error (MAPE) 6.86%, and root-mean-square error (RMSE) of 0.07. The O:C model achieved the same R ² (0.99), MAPE of 9.02%, and RMSE of 0.03. Our results demonstrate that combining FTIR data with modeling is a promising rapid and accessible method for attaining biochar stability data.

In order to estimate the ability of biochar to sequester carbon as part of greenhouse gas removal technology, there is a need for rapid and accessible estimations of biochar stability. This study employs a novel method using Fourier transform infrared spectroscopy (FTIR) to predict common stability indicators, namely H:C and O:C molar ratios. Biochars derived from barley straw were produced at temperatures from 150 to 700 °C. The greatest compositional changes of the biochars occurred between 200 and 400 °C. All biochars produced at ≥400 °C achieved H:C < 0.7 and O:C < 0.4, indicative of biochars suitable for soil application. Regression models were built using FTIR data to predict H:C and O:C molar ratios. The H:C model produced a coefficient of determination (R²) of 0.99, mean absolute percentage error (MAPE) 6.86%, and root-mean-square error (RMSE) of 0.07. The O:C model achieved the same R² (0.99), MAPE of 9.02%, and RMSE of 0.03. Our results demonstrate that combining FTIR data with modeling is a promising rapid and accessible method for attaining biochar stability data.

This research investigates a new method to predict stability data of biochar, a material used in greenhouse gas removal and soil amendment.

Material sustainability is an ongoing challenge, and their renewable sourcing is the ultimate solution. Graphene-like materials (GLMs) such as graphene, graphene oxide, reduced graphene oxide, graphene quantum dots, and graphite are home to enormous physical and chemical properties exploitable for a range of applications. Lignin, a major component in plant biomass, shares structural similarity with GLMs and, therefore, could be their renewable source. The focus of this work is on the methods employed for the extraction of lignin from biomass using deep eutectic solvents (DESs). DESs have proven to be efficient in the isolation of lignin, presenting a sustainable pathway for the production of GLMs. Results from various studies are presented to demonstrate how lignin can be converted to GLMs. The implications of these findings extend beyond material sustainability and include applications in various fields, such as electronics and energy storage devices. This Review not only addresses the existing knowledge but also contributes to the advancement of ecofriendly methodologies in the pursuit of GLMs, thereby fostering material sustainability.