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Item Multi-objective optimization and modeling of microwave-infrared pretreatment on drying and quality characteristics of cannabis (Cannabis sativa L.) using response surface methodology and artificial neural network(Taylor and Francis, 2025-03-19) Das, Pabitra Chandra; Baik, Oon-Doo; Tabil, Lope G.Electromagnetic drying of cannabis is a fast and energy-efficient method, but prolonged exposure may impact product quality. The study aimed to explore short-time microwave-infrared (MI) pretreatment of cannabis before controlled environmental drying at 25 °C and 50% RH. Using a Box-Behnken design and response surface methodology (RSM), pretreatment time (2–5 min), infrared (75–225 W), and microwave (70–210 W) power were optimized to maximize drying rate and cannabinoid contents, with minimizing color change and energy consumption. Results showed that the drying rate, color changes and tetrahydrocannabinol (THC) of dried inflorescences increased significantly (p < 0.05), whereas the energy consumption and tetrahydrocannabinolic acid (THCA) decreased due to MI pretreatment, without affecting the total THC. The optimal parameters were determined to be 225 W infrared and 210 W microwave pretreatment for 3.36 min. Comparing to untreated cannabis drying, MI pretreatment of cannabis at optimized conditions and drying resulted in shorter drying time and lower moisture content, >65% energy savings, 43% reduction of terpenes and more porous microstructure. Artificial neural network (ANN) modeling with a 3-9-6 structure outperformed RSM in predicting the response variables. Overall, this study identified that short-time MI pretreatment improved cannabis drying efficiency and neutral cannabinoids, with ANN modeling offering accurate predictions.Item Impact of Radiofrequency and Microwave Heating on the Nutritional and Antinutritional Properties of Pulses: A Review(Wiley, 2025-02) Das, Pabitra Chandra; Baik, Oon-Doo; Tabil, Lope G.; Rajagopalan, NandhakishorePulses, which are the dry seeds of legume crops, have gained global popularity, leading to a notable rise in their production. They are rich in protein, minerals, fibers, and low in fat content. However, they have some antinutrients that need to be removed. Novel techniques like radiofrequency (RF) and microwave (MW) heating can enhance pulse quality by reducing the antinutrients. The key mechanism behind this improvement is the rapid heating that disrupts the native structure of the pulses. These technologies offer several advantages, including speed, consistency, sustainability, and energy efficiency. The effectiveness of RF and MW processing depends on the heating conditions used and the kind of pulses being treated. This review highlights the mechanisms and influencing factors of RF and MW heating as well as their effect on the nutritional and antinutritional qualities of various pulses. Additionally, the limitations of these technologies are summarized, and future research prospects focusing on pulse processing are identified.Item Microwave-infrared drying of cannabis (Cannabis sativa L.): Effect on drying characteristics, energy consumption and quality(Elsevier, 2024-02) Das, Pabitra Chandra; Baik, Oon-Doo; Tabil, Lope G.Conventional cannabis drying is time-consuming and energy intensive. A quick and dependable drying of cannabis is essential to ensure high-quality products to meet increasing demands. This study explored a combined microwave and infrared (MI) drying on cannabis comparing with control environmental (CE) drying. MI was very efficient with a short drying time of 16–200 min, high moisture diffusivity of 7.95×10−09-8.70×10−08 m2/s, and low energy consumption of 390.49–1611.42 kJ. The Page and Modified Page drying models fitted well to describe and predict the MI drying characteristics of cannabis. Microstructural images identified shrinkage in glandular trichomes of cannabis, whereas colorimetric assessment resulted in alteration of color attributes due to MI drying. It also facilitated the conversion of acidic cannabinoids to their neutral forms by decreasing tetrahydrocannabinolic acid (THCA) in g/g of dry matter from 20.15% to 7.57% and increasing tetrahydrocannabinol (THC) from 6.31% to 16.65% that insignificantly (p≥0.05) affected the total THC level. MI drying resulted in a total terpenes concentration (%g/g of dry matters) of 0.541–0.730, insignificantly lower than CE drying (0.768). Overall, the study highlights MI as a rapid and energy-efficient drying for obtaining high quality cannabis, particularly for medicinal applications.Item Postharvest Operations of Cannabis and Their Effect on Cannabinoid Content: A Review(MDPI, 2022-08) Das, Pabitra Chandra; Vista, Alec Roger; Tabil, Lope; Baik, Oon-DooIn recent years, cannabis (Cannabis sativa L.) has been legalized by many countries for production, processing, and use considering its tremendous medical and industrial applications. Cannabis contains more than a hundred biomolecules (cannabinoids) which have the potentiality to cure different chronic diseases. After harvesting, cannabis undergoes different postharvest operations including drying, curing, storage, etc. Presently, the cannabis industry relies on different traditional postharvest operations, which may result in an inconsistent quality of products. In this review, we aimed to describe the biosynthesis process of major cannabinoids, postharvest operations used by the cannabis industry, and the consequences of postharvest operations on the cannabinoid profile. As drying is the most important post-harvest operation of cannabis, the attributes associated with drying (water activity, equilibrium moisture content, sorption isotherms, etc.) and the significance of novel pre-treatments (microwave heating, cold plasma, ultrasound, pulse electric, irradiation, etc.) for improvement of the process are thoroughly discussed. Additionally, other operations, such as trimming, curing, packaging and storage, are discussed, and the effect of the different postharvest operations on the cannabinoid yield is summarized. A critical investigation of the factors involved in each postharvest operation is indeed key for obtaining quality products and for the sustainable development of the cannabis industry.Item Enhancing drying efficiency and terpene retention of cannabis using cold plasma pretreatment(ScienceDirect, 2025-11) Das, Pabitra Chandra; HEYDARI FOROUSHANI, MOHAMAD MEHDI; Baik, Oon-Doo; Zhang, Lifeng; Tabil, LopeHang-drying of cannabis at room conditions is a slow process and leads to the risk of microbial growth. This method can sometimes prevent cannabis from reaching the equilibrium moisture content (EMC) below the safe storage threshold. On the other hand, high-temperature drying techniques are faster but negatively impact the secondary metabolites. Cold plasma (CP) is a novel technique explored in this study to treat cannabis at various operational conditions of plasma jet (power: 300, 350, and 400 W, time: 20, 30, and 40 s) prior to drying at environmental conditions of 25°C and 50 % RH. The findings revealed that untreated cannabis samples reached an equilibrium moisture content (EMC) of approximately 16 % in 1260 min. In contrast, CP-pretreated samples achieved lower EMCs of 10–14 % within 690–840 min. CP pretreatment also resulted in high moisture diffusivity, lower energy consumption, and higher energy efficiency. Increasing CP power and residence time accelerated the decarboxylation of cannabinoids, leading to the formation of more tetrahydrocannabinol (THC) and less tetrahydrocannabinolic acid (THCA), without significantly affecting the total THC (27.45 % untreated vs. 25.82 % - 28.36 % g/ g of dry matter in CP pretreated samples). Compared with untreated dried inflorescences, the 400 W and 30 s CP treated inflorescences resulted in the retention of 96 % of terpenes, whereas all 300 W CP treated samples retained > 90 % of terpenes. Overall, the study highlights that CP pretreatment is a promising technology for the cannabis industry in shortening the drying time and preserving the product quality, especially terpenes.Item Synchrotron X-ray imaging study on the mechanism of solids transfer to bitumen froth during oil sands flotation 1: True flotation(Elsevier, 2025-01-18) Zhang, Hanyu; Xia, Liuyin; Zhu, Yanfei; Gasilov, Sergey; He, Iris; Ding, XiaofanUnwanted mineral solids in bitumen froth can lead to increased solvent usage and higher hydrocarbon loss in downstream processing, negatively impacting the cost-effectiveness and sustainability of synthetic crude oil production. Enhancing the quality of bitumen froth with fewer solids is a goal for oil sands processors. This study presents an in-situ analysis of the particle size distribution and association of solids in bitumen froth, thereby uncovering solids transport mechanisms, such as true flotation. Oil sands flotation experiments were conducted with 30% pulp density, at 50 °C and pH 8.5. The collected bitumen froth was immediately characterized using synchrotron-based X-ray imaging by a monochromatic X-ray with photon energy of 60 keV provided by 05ID-2 beamline of the BioMedical Imaging and Therapy (BMIT) facility at the Canadian Light Source (CLS). This characterization method can finish a typical CT scan with 2000 projections in less than 3 min, and thus allows for in-situ imaging of freshly prepared bitumen froth without the need for special arrangements, such as freezing. 14, 234 unwanted solids carried over into bitumen froth were visualized, 98.9 wt% of them were sand particles, which is consistent with mineral liberation analysis (MLA) results. This study introduced an innovative image segmentation technique to quantify the transfer of particles into the bitumen froth via true flotation. Statistical analysis revealed that approximately 53 wt% of sand particles were collected due to true flotation. Furthermore, the median particle size (P50) for sand particles entering froth by true flotation was determined to be 67.6 μm, significantly larger than the 30.6 μm observed for particles transferring through entrainment or entrapment.Item Enhancing drying efficiency and terpene retention of cannabis using cold plasma pretreatment(Elsevier, 2025-02-11) Das, Pabitra Chandra; Heydari, Mohamad Mehdi; Baik, Oon-Doo; Zhang, Lifeng; Tabil, LopeHang-drying of cannabis at room conditions is a slow process and leads to the risk of microbial growth. This method can sometimes prevent cannabis from reaching the equilibrium moisture content (EMC) below the safe storage threshold. On the other hand, high-temperature drying techniques are faster but negatively impact the secondary metabolites. Cold plasma (CP) is a novel technique explored in this study to treat cannabis at various operational conditions of plasma jet (power: 300, 350, and 400 W, time: 20, 30, and 40 s) prior to drying at environmental conditions of 25°C and 50 % RH. The findings revealed that untreated cannabis samples reached an equilibrium moisture content (EMC) of approximately 16 % in 1260 min. In contrast, CP-pretreated samples achieved lower EMCs of 10–14 % within 690–840 min. CP pretreatment also resulted in high moisture diffusivity, lower energy consumption, and higher energy efficiency. Increasing CP power and residence time accelerated the decarboxylation of cannabinoids, leading to the formation of more tetrahydrocannabinol (THC) and less tetrahydrocannabinolic acid (THCA), without significantly affecting the total THC (27.45 % untreated vs. 25.82 % - 28.36 % g/ g of dry matter in CP pretreated samples). Compared with untreated dried inflorescences, the 400 W and 30 s CP treated inflorescences resulted in the retention of 96 % of terpenes, whereas all 300 W CP treated samples retained > 90 % of terpenes. Overall, the study highlights that CP pretreatment is a promising technology for the cannabis industry in shortening the drying time and preserving the product quality, especially terpenes.Item Electrostatic Particle Ionization for Reduction in Livestock and Potash Dust(MDPI, 2025-01-15) Martel, Myra; Taylor, Matthew; Kirychuk, Shelley; Choi, Kwangseok; Guo, Huiqing; Zhang, LifengAirborne dust is an important contaminant affecting the health and the environment, and a crucial concern in many workplaces such as animal facilities and potash mines. One of the techniques used for dust control is electrostatic particle ionization (EPI). This technology has been proven effective in reducing airborne dust; however, it has downsides, such as the generation of ozone and corrosion of electrodes. Thus, this study tested a corrosion-resistant carbon-fiber discharge electrode and compared it with electrodes commonly used in EPI systems, that is, stainless-steel and tungsten electrodes, in terms of collection efficiency for potash dust and wheat flour (representative of livestock dust), ozone production, and power consumption. The carbon-fiber electrode performed comparably to stainless-steel electrodes, particularly for potash dust, and performed better than the tungsten electrode in terms of dust collection efficiency. Moreover, it had the lowest energy consumption and generated the least amount of ozone. However, because of the limitations of this study (e.g., fewer samples, low air velocity, controlled conditions, and the use of wheat flour instead of livestock dust), tests under real barn or mining conditions are necessary to confirm the results.Item Chiral nematic cellulose nanocrystal films: Sucrose modulation for structural color and dynamic behavior(International Journal of Biological Macromolecules, 2025-01) Babaeighazvini, Amin; Vafakish, Bahareh; Acharya, BishnuThis study explores the effect of sucrose addition on the properties of chiral nematic cellulose nanocrystal (CNC) films for potential food industry applications, including biodegradable packaging and food coloring. The addition of sucrose altered the films' structural color, shifting from blue in pure CNC films to aqua blue, green, yellow-green, and red with increasing sucrose concentrations (up to 21 %). Surface analysis revealed a reduction in contact angle from 96° to 48° due to sucrose's hydrophilic nature and smoother film surfaces. XRD results indicated a decrease in crystallinity from 84.5 % to 15.6 %, linked to the disruption of CNC alignment by sucrose. Mechanical testing showed reduced tensile strength (138 MPa to 35 MPa) and Young's modulus (1.634 GPa to 70 MPa) with higher sucrose content. Notably, over the storage time, films with 21 % sucrose exhibited dynamic structural coloration caused by localized sucrose recrystallization, leading to pitch shifts and color transitions. These findings demonstrate the tunable optical and mechanical properties of CNC-sucrose films, positioning them as promising materials for sustainable food packaging and responsive coatings.Item A novel biochar adsorbent for treatment of perfluorooctanoic acid (PFOA) contaminated water: Exploring batch and dynamic adsorption behavior(Journal of Water Process Engineering, 2024-11) Afrooz, Malihe; Zeynali, Rahman; Soltan, Jafar; McPhedran, KerryPerfluoroalkyl substances (PFAS), like perfluorooctanoic acid (PFOA), are of concern worldwide given they are ubiquitous in the environment. In this study, the treatment of PFOA-contaminated water was assessed using biochar adsorbents produced from raw canola straw (RCS) through chemical activation with H3PO4 and ZnCl2 and microwave-assisted pyrolysis (MWP). MWP conditions were evaluated to create optimal H3PO4-treated (PBC) and ZnCl2-treated (ZnBC) biochar adsorbents with treatments determined using a central composite design (CCD) based on the response surface methodology (RSM) considering activator concentration, and microwave heating time and power. The highest PFOA removal efficiency for PBC (3.0 mol/L) was achieved at 92 % (368 μg/g), while for ZnBC (0.55 mol/L) it was 84 % (336 μg/g). In contrast, untreated biochar and RCS had markedly lower PFOA removals of 5 % and 1 %, respectively. Activation of biochar under optimal pyrolysis conditions (6 min at 600 W) led to increased chemical functional groups, porosity, and surface area, as confirmed by FT-IR, XPS, and BET. The kinetic study indicated that chemisorption was the primary PFOA adsorption mechanism, while the Freundlich isotherm model suggested heterogeneous multilayer adsorption for PFOA removal. Further, background salts enhanced PFOA adsorption through divalent bridges and salting-out mechanisms. PBC and ZnBC adsorbents performed well over a broad pH range of 3 to 9. Lastly, Yan and Yoon-Nelson models were used to assess adsorption breakthrough for a model fixed-bed adsorption system. This study exhibits that PBC and ZnBC adsorbents, derived from accessible biomass, offer an environmentally friendly solution to remove PFOA from contaminated water.Item Unraveling chemical origins of dendrite formation in zinc-ion batteries via in situ/operando X-ray spectroscopy and imaging(Nature Portfolio, 2024) Dai, Hongliu; Sun, Tianxiao; Zhou, Jigang; Wang, Jian; Chen, Zhangsen; Zhang, Gaixia; Sun, ShuhuiTo prevent zinc (Zn) dendrite formation and improve electrochemical stability, it is essential to understand Zn dendrite growth, particularly in terms of morphology and relation with the solid electrolyte interface (SEI) film. In this study, we employ in-situ scanning transmission X-ray microscopy (STXM) and spectro-ptychography to monitor the morphology evolution of Zn dendrites and to identify their chemical composition and distribution on the Zn surface during the stripping/plating progress. Our findings reveal that in 50 mM ZnSO4, the initiation of moss/whisker dendrites is chemically controlled, while their continued growth over extended cycles is kinetically governed. The presence of a dense and stable SEI film is critical for inhibiting the formation and growth of Zn dendrites. By adding 50 mM lithium chloride (LiCl) as an electrolyte additive, we successfully construct a dense and stable SEI film composed of Li2S2O7 and Li2CO3, which significantly improves cycling performance. Moreover, the symmetric cell achieves a prolonged cycle life of up to 3900 h with the incorporation of 5% 12-crown-4 additives. This work offers a strategy for in-situ observation and analysis of Zn dendrite formation mechanisms and provides an effective approach for designing high-performance Zn-ion batteries.Item Low adsorption affinity of athabasca oil sands naphthenic acid fraction compounds to a peat-mineral mixture(Elsevier, 2024-04-24) Meulen, Ian J. Vander; Steiger, Bernd G.K.; Asadi, Mohsen; Peru, Kerry M.; Degenhardt, Dani; McMartin, Dena W.; McPhedran, Kerry M.; Wilson, Lee D.; Headley, John V.Much of the toxicity in oil sands process-affected water in Athabasca oil sands tailings has been attributed to naphthenic acids (NAs) and associated naphthenic acid fraction compounds (NAFCs). Previous work has characterized the environmental behaviour and fate of these compounds, particularly in the context of constructed treatment wetlands. There is evidence that wetlands can attenuate NAFCs in natural and engineered contexts, but relative contributions of chemical, biotic, and physical adsorption with sequestration require deconvolution. In this work, the objective was to evaluate the extent to which prospective wetland substrate material may adsorb NAFCs using a peat-mineral mix (PMM) sourced from the Athabasca Oil Sands Region (AOSR). The PMM and NAFCs were first mixed and then equilibrated across a range of NAFC concentrations (5–500 mg/L) with moderate ionic strength and hardness (∼200 ppm combined Ca2+ and Mg2+) that approximate wetland water chemistry. Under these experimental conditions, low sorption of NAFCs to PMM was observed, where sorbed concentrations of NAFCs were approximately zero mg/kg at equilibrium. When NAFCs and PMM were mixed and equilibrated together at environmentally relevant concentrations, formula diversity increased more than could be explained by combining constituent spectra. The TOC present in this PMM was largely cellulose-derived, with low levels of thermally recalcitrant carbon (e.g., lignin, black carbon). The apparent enhancement of the concentration and diversity of components in PMM/NAFCs mixtures are likely related to aqueous solubility of some PMM-derived organic materials, as post-hoc combination of dissolved components from PMM and NAFCs cannot replicate enhanced complexity observed when the two components are agitated and equilibrated together.Item Experimental and Modeling Studies of Torrefaction of Spent Coffee Grounds and Coffee Husk: Effects on Surface Chemistry and Carbon Dioxide Capture Performance(ACS Publications, 2022) Mukherjee, Alivia; OKOLIE, JUDE; Niu, Catherine; Dalai, Ajay K.Torrefaction of biomass is a promising thermochemical pretreatment technique used to upgrade the properties of biomass to produce solid fuel with improved fuel properties. A comparative study of the effects of torrefaction temperatures (200, 250, and 300 °C) and residence times (0.5 and 1 h) on the quality of torrefied biomass samples derived from spent coffee grounds (SCG) and coffee husk (CH) were conducted. An increase in torrefaction temperature (200–300 °C) and residence time (0.5–1 h) for CH led to an improvement in the fixed carbon content (17.9–31.8 wt %), calorific value (18.3–25 MJ/kg), and carbon content (48.5–61.2 wt %). Similarly, the fixed carbon content, calorific value, and carbon content of SCG rose by 14.6–29 wt %, 22.3–30.3 MJ/kg, and 50–69.5 wt %, respectively, with increasing temperature and residence time. Moreover, torrefaction led to an improvement in the hydrophobicity and specific surface area of CH and SCG. The H/C and O/C atomic ratios for both CH- and SCG-derived torrefied biomass samples were in the range of 0.93–1.0 and 0.19–0.20, respectively. Moreover, a significant increase in volatile compound yield was observed at temperatures between 250 and 300 °C. Maximum volatile compound yields of 11.9 and 6.2 wt % were obtained for CH and SCG, respectively. A comprehensive torrefaction model for CH and SCG developed in Aspen Plus provided information on the mass and energy flows and the overall process energy efficiency. Based on the modeling results, it was observed that with increasing torrefaction temperature to 300 °C, the mass and energy yield values of the torrefied biomass samples declined remarkably (97.3% at 250 °C to 67.5% at 300 °C for CH and 96.7% at 250 °C to 75.1% at 300 °C for SCG). The SCG-derived torrefied biomass tested for CO2 adsorption at 25 °C had a comparatively higher adsorption capacity of 0.38 mmol/g owing to its better textural characteristics. SCG would need further thermal treatment or functionalization to tailor the surface properties to attract more CO2 molecules under a typical post-combustion scenario.Item Techno – Economic analysis of activated carbon production from spent coffee grounds: Comparative evaluation of different production routes(Elsevier, 2022) Mukherjee, Alivia; OKOLIE, JUDE; Niu, Catherine; Dalai, Ajay K.Activated carbon (AC) has gained immense popularity owing to its excellent physicochemical properties and its ability to remove carbon dioxide (CO2) from flue gas stream. This study examines the potential of spent coffee grounds (SCG) as a precursor for activated carbon (AC) production via prominent thermochemical conversion technologies. Different production routes, such as slow pyrolysis, activation, and deep eutectic solvent (DES) functionalization were compared in terms of their economic viability. Three scenarios (Scenario 1–3) involving combinations of the technologies and production routes were evaluated. Scenario 1 comprises of slow pyrolysis, CO2 activation and flue gas recycling for activation. Scenario 2 includes flue gas combustion while the third scenario comprise of flue gas combustion and DES impregnation. All processes were simulated with Aspen plus, while a detailed cash flow analysis was used to estimate the profitability parameters. The price of AC was found to be the most crucial determinant of an AC production plant’s viability and feasibility. The minimum selling price (MSP) of AC samples produced from scenarios 1,2 and 3 are U.S $0.15/kg, $0.21/kg, $0.28/kg respectively. The price of pristine AC and DES treated AC were lower than the commercially available activated carbon (U.S $0.45/kg).Item A New Dataset of Leaf Optical Traits to Include Biophysical Parameters in Addition to Spectral and Biochemical Assessment(2022) Peters, Reisha; Noble, ScottTo enable future improvement on current leaf optical property models, more data incorporating a larger range of measured properties is needed. To this end, a dataset was collected to associate spectral measurements (ultraviolet, visible, and near infrared) with biochemical and biophysical properties of leaves. The leaves represented in this dataset were selected to provide representation of agricultural species and of leaves with a wide variety of color (pigment) expression, surface characteristics, and age. Data collected for 290 leaf samples studied in this project included multiple spectral measurement geometries and ranges, biochemical assessment of chlorophyll a and b, carotenoids, and anthocyanins, and biophysical assessment of leaf thickness and surface characteristics that has not previously been a focus in other leaf datasets. The methods and results associated with this dataset are described in this work.