Laboratory-scale Experiments Research Articles

An improved jute ribbon retting using microbial consortia from jute retting water

The extraction of jute fibers, known as retting, traditionally involves immersing harvested jute plants in water to facilitate microbial degradation of pectin and hemicellulose, thereby separating the bast fibers. However, this method is plagued by inefficiencies, including prolonged retting times and water scarcity during the dry season. This study investigates the efficacy of bacterial consortia in jute retting, aiming to shorten retting duration and enhance fiber quality. Laboratory-scale experiments evaluated the enzymatic profiles of bacterial isolates from retting water, assembling seven consortia based on enzymatic capabilities. These consortia were tested in lab-scale retting experiments. The results demonstrate a significant reduction in retting time, with consortia C-4 and C-5 completing the process in just 10 days, a 50 % reduction compared to traditional methods. Consortia C-4 exhibited the highest tensile strength at 801.00±26.28 MPa, a 67.92 % increase over the control group. Molecular identification revealed that key bacterial strains belonged to the genus Bacillus, with enzymatic profiles efficiently breaking down pectin and hemicellulose while preserving cellulose integrity. XRD analysis showed consistent patterns across all jute fiber samples, with characteristic peaks at 2θ angles of 15°-16° and 22°-23°. The crystallinity index for C-4 was highest at 65.99 %, followed by C-5 (64.89 %) and C-6 (64.93 %), indicating enhanced crystalline regions. This study underscores the efficacy of bacterial consortia in jute retting, offering a sustainable solution to decrease retting duration, minimize water usage, and enhance fiber quality for the jute industry.

Strain Field Development, Fracturing, and Gas Ejection in Decoupled Charge Blasting Using Granite Cylinders

This study explored the fracture process of granite cylinders with a centric charge, varying decoupling ratios by conducting laboratory-scale experiments and numerical simulations. In experiments, the three-dimensional (3D) digital image correlation (DIC) technique was employed, using frames captured by two synchronized high-speed cameras. This instrumentation permitted the observation of full-field strain variation, the development of fractures, and gaseous products escaping from the cylinders’ surfaces. Granite cylinders measuring 240 mm in diameter and 300 mm in length served as specimens in blasting experiments, and each specimen had a charge of approximately 3 g. Specimens had a centric blasthole with a diameter of either 10 mm, 14 mm, or 20 mm. The corresponding decoupling ratio varied from 1.8 to 3.6, and the gap between the charge and the blasthole wall was filled with water or air. The experimental results showed that: (1) specimens with decoupling ratios of 1.9 and 2.6 exhibited initial strains on the cylindrical surface between 20 μs and 40 μs. (2) Specimens with water-filled blastholes developed fractures faster and in a denser manner compared to those with air-filled blastholes. In addition, fractures resulting from air-filled blastholes appeared smoother than those from water-filled blastholes. (3) The gas ejection time for the air-filled blasthole remained basically consistent across decoupling ratios ranging from 1.5 to 3.61, varying between 400 μs and 520 μs. The utilization of water-filled blastholes effectively minimized the escape of gaseous products from the cylindrical surface. Numerical simulation conducted with LS-DYNA exhibited results that aligned well with the observed fracture patterns in the experiments. This study aims to provide a better understanding of the fundamental mechanisms of rock behaviors in decoupled charge blasting.

A Generative adversarial network model for estimating temporal frequency variation of vehicle-bridge interaction using modified Stockwell transform

The presence of massive and directional vehicles moving on a railroad bridge causes temporal fluctuations in the fundamental frequencies of both bridge and vehicle systems, making traditional structural inspections difficult to employ effectively. Thus, this paper proposes an image-to-image Generative Adversarial Network (GAN) that estimates temporal frequency variation for the vehicle-bridge interaction system. To address the challenges associated with conventional approaches, eigenvalue analysis, numerical substitution, and Fourier series approximations are examined using a simple degree of freedom and a more complex model. Thus, the GAN model is proposed to overcome those limitations. In the framework, based on the properties of a real bridge and vehicle model, the modified Stockwell transform of bridge acceleration from the dynamic simulation is used as input data with the paired data from the numerical substitution approach. Then, the model is validated through quantitative measures and laboratory scale experiments. Results showed that the model has strong performances across the various scenarios, demonstrating the potential for bridge condition assessment under operational conditions.

Effect of CaO–SiO2–MgO–CaF2 slags on deep deoxidation and desulphurisation of low-Ni 201 stainless steel by simultaneous consideration of multiple slag–steel reactions

Effects of the CaO–SiO2–MgO–CaF2 slag on the deep deoxidation and desulphurisation of low-nickel 201 stainless steel (SS) are investigated via laboratory-scale experiments and a developed thermodynamic model. The model was developed based on the slag–steel equilibrium theory, the law of mass conservation, as well as the ion and molecule coexistence theory. And the model involves the Si–Mn–Cr–Fe–S–O reaction system. By comparing the measured values and the model-predicted values, the model has been proved that can effectively predict the equilibrium oxygen and sulphur contents in 201 SS with CaO–SiO2–MgO–CaF2 slag. The average deviation between the model-predicted value and the measured value is <1.5×10−6. Both the model-predicted values and the measured values show that a high basicity is beneficial for the deoxidation and desulphurisation of steel. Moreover, the measured values of the minimum oxygen and sulphur contents are 8.69×10−6 and 8.10×10−6, respectively, which are obtained at B≥1.9. Increasing the MgO content at B=1.7 to within 5 wt-% slightly improves the deoxidation and desulphurisation of the steel, while it has no effect at (% MgO)≥7.0. Increasing the CaF2 content in the range of 20–40 wt-% slightly decreases the equilibrium sulphur content (3.6×10−6) in the steel, but it does not affect the equilibrium oxygen content. As a result, the optimum slag for both the deoxidation and desulphurisation of 201 SS is to maintain a binary basicity range of 1.9–2.1, with MgO content at saturation state and CaF2 content at 40 wt-%. In addition, the deoxidation and desulphurisation mechanisms between CaO–SiO2–MgO–CaF2 initial slag and 201 SS are discussed based on the developed model.

Experimental Investigation of Amine Regeneration for Carbon Capture through CO2 Mineralization

Summary The most common method for point-source carbon capture involves the absorption of CO2 from flue gas by amine solutions. The CO2 is then stripped from the amine solution by desorption with steam or heat. While amine solvents exhibit high CO2 absorption efficiency, their desorption process consumes a substantial amount of energy. A more energy-efficient alternative for the regeneration of the amine can be done through a mineralization process. Past studies have shown the feasibility of mineralizing captured CO2 from amine solution using calcium oxide (CaO) or other CaO-containing industrial waste. This study aims to show experimentally the extent of mineralization over time in near-ambient conditions and develop a mechanistic model. Lab-scale experiments are conducted to determine the absorption characteristics of CO2 in monoethanolamine (MEA) solutions and the extent of mineralization. We observe that pH serves as an indicator for CO2 loading in amine solutions. At high concentrations of MEA, CO2 absorption efficiency is about 0.5 mol CO2/mol MEA. Under ambient pressure and a temperature of 40°C, CaO effectively mineralizes CO2 and regenerates MEA. The CaO initially reacts with water to produce calcium hydroxide (Ca(OH)2) and subsequently reacts with dissolved CO2, forming calcium carbonate (CaCO3). Both 13C nuclear magnetic resonance (NMR) and FTIR indicate that MEA can be regenerated with an efficiency close to 69 to 98%, by comparing the carbamate and bicarbonate peaks in the 13C NMR response. A model to describe the absorption and mineralization reaction is proposed using the PHREEQC software; the pH is matched within less than 3% error. This study demonstrates that CO2 desorption from MEA solutions can occur through mineralization, converting CO2 into carbonates at low pressure and temperature with CaO. This method has lower energy consumption and results in the most stable form of CO2, making it a safer sequestration strategy than supercritical CO2 storage in reservoirs.

A novel strategy for recovery of heavy metals and synthesis of Co-rich alloy from the alkali-treated tungsten residue using photovoltaic silicon kerf waste

The treatment of spent cemented carbides using the conventional alkali-acid leaching process results in the generation of hazardous solid waste tungsten leaching residue. This study proposed an alternative process using the alkali-treated tungsten leaching residue (AW-residue) without the acid leaching step, preserving Co in the residue. By using photovoltaic silicon kerf waste (SKW) as a reducing agent, heavy metals (Co, Ni, W, Nb, and Ta) were efficiently extracted from AW-residue and a Co-rich alloy was obtained. The silicothermic reduction process facilitated the recovery of iron group metals (Co, Ni, and Fe) and effectively captured trace refractory metals (W, Ta, and Nb). Phase separation occurred through reduction reaction and viscosity-driven processes between the Co-rich alloy and the slag. Optimal conditions were identified as 20% SKW addition, MgO crucible, and a holding time of 120 min, achieving a total recovery yield of 95.5%, with specific yields for Co (97.7%), Ni (97.0%), W (82.5%), Nb (76.3%), and Ta (70.5%). A 20 kg pilot-scale experiment confirmed the feasibility of the process, yielding 47.0% Co-rich alloy from AW-residue compared to 48.3% in lab-scale experiment, and producing a harmless slag phase. This environmentally friendly approach promotes sustainable recycling of valuable metals in the tungsten industry.

Optimum Tuning for the High-efficiency Removal of Malodorous Gas Containing Hydrogen Sulphide Using Biological Treatment

Hydrogen sulfide, as the main pollutant causing stench, has always been one of the main problems in environmental protection. In order to promote the practical application, a pilot study was carried out in this work on the biological treatment of hydrogen sulfide malodorous gas by the combined process of biological drip filtration on the basis of our previous laboratory-scale experiments. After enlarging the reactor in pilot experiment, various factors affecting the deodorization efficiency are compared in pilot scale and laboratory scale, and the optimum pilot condition are obtained. Furthermore, the mechanism of biological deodorization is analyzed. Based on the results of the comparison between the previous laboratory-scale and the pilot-scale of this work, possible bottlenecks and challenges of biological deodorization technology from pilot to industrial application are discussed. The technical approach proposed in this work provides an economical and efficient feasible scheme for biological deodorization in the industrial practice.

EFFECT OF ECO ENZYME ADDITION ON THE IMPROVEMENT OF WATER QUALITY, REDUCTION OF AMMONIA AND METAL IN DUG WELL WATER

This study aims to: (1) Analyze the effect of artificial eco enzyme addition on improving the quality of dug well water based on pH, TDS, TSS, and DO parameters; (2) Analyze the effect of artificial eco enzyme addition on reducing ammonia and metal content in dug well water. The type of research is a laboratory-scale experiment with a quantitative approach to dug well water samples treated using a complete randomized design (CRD). The characteristics of the experimental test are 4 times treatment 1 time repetition in a homogeneous sample population. The conclusion of the research is that the provision of artificial eco enzyme has an effect in the form of an average increase and decrease in each parameter of the water quality of the dug well, namely pH 0,4, TDS 22 mg/l, TSS 13,3 mg/l, DO 4,2 mg/l, NH3 2,5 mg/l, Fe 0,4 mg/l, and Mn 0,03 mg/l. Based on one-way ANOVA testing resulted in sig. 0.001 0.05 and Duncan testing resulted in different number notations in each sample with sig. 1.000 0.05 which means the addition of eco enzyme gives a real influence on improving the quality of well water.

Efficient treatment of high-concentration pharmaceutical wastewater with high-salinity by chemical synthesis coupling with evaporation: From lab-scale to pilot-scale

This study focused on the treatment of high-concentration pharmaceutical wastewater with high-salinity by pretreatment of chemical synthesis coupling with evaporation. Via chemical synthesis, this pretreatment process was developed to remove the organic matter that inhibited evaporation of wastewater, resulting in improved evaporation efficiency. Lab-scale results demonstrated that under the optimum conditions (∼pH 9, 2 mL/L demulsifier, 98 mM/L H2O2, 3 h of aeration time, 80 °C, 500 mg/L PAC, and 20 mg/L PAM), 54.9 % of COD was successfully removed by single pretreatment and 98.6 % after coupling with evaporation. Compared to the 80.1 % COD removal efficiency of direct evaporation of 100 mL with 30 min, the pretreatment process coupling with evaporation demonstrated superior performance and halved the evaporation time. A pilot-scale chemical synthesis pretreatment (120 t/d) was further developed to treat pharmaceutical wastewater of both high COD concentrations and high salinity. Under the optimal conditions determined in the lab-scale experiments, the pilot-scale achieved a COD removal efficiency of 49 % with a single pretreatment and 95.8 % after coupling with mechanical vapor recompression (MVR). Additionally, the obtained salt appeared visually clean and white compared to that obtained from the treated wastewater without pretreatment. Furthermore, to elucidate the possible mechanisms driving the efficient removal of COD, GC–MS was performed on the wastewater before and after pretreatment, and the resulting products from pretreatment in pilot-scale applications were further determined by both FTIR and GC–MS. It was proposed that the aldol condensation reaction increased the formation of carbon chains to macromolecular compounds might be the possible mechanism. This study gives insights into the future application of low-investment and low-cost technology in the treatment of high-concentration pharmaceutical wastewater with high salinity in industry.

Waste solution of acrylic-based emulsion with low solid content for cement concrete curing: a lab-scale study

In this study, we investigate using acrylic and acrylic-styrene emulsions as curing solution to enhance water resistance and prevent cracking in cement concrete surfaces. Our main objective is to investigate the possibilities of utilizing washing waste generated during the Rhomn & Haas factory - Dow Chemical Vietnam production process. This waste is currently being treated as solid even though it contains anywhere from 10-45% solid content. Through laboratory-scale experiments and analysis, we aim to assess the feasibility of employing this waste material as a cost-effective, technically sound, and environmentally sustainable solution for curing compound of concrete. The findings of this research have the potential to contribute to the advancement of eco-friendly waste management techniques while improving the durability and effectiveness of cement structures.

Effectiveness of empty fruit bunch ash as the catalyst for palm oil transesterification

Empty Fruit Bunch (EFB) resulted from oil palm plantations and mills can be converted into ash through open combustion. The EFB ash then treated by simple calcination and used as a heterogeneous catalyst for biodiesel production. The characteristics of EFB ash were identified based on its elemental composition, porous structure, and active site size. The effectivity of the EFB ash as a catalyst was tested in a transesterification reaction of Refined Bleached Deodorized Palm Oil (RBDPO) with excess methanol (30 %-w) in various catalyst loads (in%-wt). The lab-scale experiments were conducted in a three-neck glass reactor, which was put on the hot plate stirrer at 450 rpm. The EFB ash performed the best as a catalyst by attaining optimal conversion at 65 °C for 1 h with a 16 %-wt of catalyst load. In this condition, most of the standard quality of biodiesel were complied with total glycerol under 0.24% and ester methyl contents up to 98.9 %. The characteristics tests showed that the properties and active side of the EFB ash are excellent after calcination at 600 for 5 h. The recyclability test of EFB ash as a catalyst showed high performance in two repetition cycles, each showing an increase in the yield of biodiesel, which was 92.21 % in cycle 2 and 91.23 % in cycle 3.

Anti-turbulent efficiency of oil-soluble polymer solutions and colloid systems flowing through cylindrical channel

Relevance. The use of anti-turbulent additives for transporting hydrocarbon liquids through main pipelines allows reducing significantly the energy consumption of pumping power stations. Aim. Comparative analysis of the anti-turbulent efficiency of high-molecular polymers and compositions of surfactants. Methods. Laboratory-scale experimentation aimed to study the flow of dilute polymer solutions and dispersed surfactant systems through a cylindrical channel of a turbulent rheometer. Results. The author has carried out the comparative experimental studies of the anti-turbulent efficiency of extremely dilute solutions of polymers and colloidal systems. The results were obtained that suggest a higher anti-turbulent efficiency of high-molecular-weight polymers compared to micellar surfactant systems. Solutions of high molecular weight polybutadiene and aluminum polyhydroxydicarboxylates in gasoline were used as samples for the experimental comparison of hydrodynamic efficiency. The paper describes the laboratory setup, on which the studies were carried out, and introduces the formulas used for quantitative calculations. The structure of polymer solutions and colloidal systems is considered and a theoretical explanation is given for the preferential use in industrial practice of high-molecular polymers in extremely low concentrations in real pipelines. It was found out that the mechanisms of degradation of antiturbulent properties of polymer solutions and dispersed surfactant systems are different. This is due to the difference in the structure of macromolar coils of polymer with an immobilized solvent and that of micelles from low molecular amphiphilic compounds. The paper introduces the arguments that explain the degradation of the antiturbulent properties of polymers not by the destruction of carbon-chain macromolecules, but by decomposition in a turbulent flow of the original large associates, consisting of a large number of chains, into individual and smaller macromolecular coils with an immobilized solvent.

Bio-Based Materials as a Sustainable Solution for the Remediation of Contaminated Marine Sediments: An LCA Case Study.

Contaminated sediments may induce long-term risks to humans and ecosystems due to the accumulation of priority and emerging inorganic and organic pollutants having toxic and bio-accumulation properties that could become a secondary pollution source. This study focused on the screening of novel bio-based materials to be used in the decontamination of marine sediments considering technical and environmental criteria. It aimed to compare the environmental impacts of cellulose-based adsorbents produced at lab scale by using different syntheses protocols that involved cellulose functionalization by oxidation and branching, followed by structuring of an aerogel-like material via Soxhlet extraction and freeze-drying or their combination. As model pollutants, we used 4-nitrobenzaldehyde, 4-nitrophenol, methylene blue, and two heavy metals, i.e., cadmium and chromium. When comparing the three materials obtained by only employing the Soxhlet extractor with different solvents (without freeze-dying), it was observed that the material obtained with methanol did not have a good structure and was rigid and more compact than the others. A Life Cycle Assessment (LCA) was conducted to evaluate the environmental performance of the novel materials. Apart from the hierarchical categorization of the materials based on their technical and environmental performance in eliminating organic pollutants and heavy metal ions, it was demonstrated that the cellulose-based material obtained via Soxhlet extraction with ethanol was a better choice, since it had lower environmental impacts and highest adsorption capacity for the model pollutants. LCA is a useful tool to optimize the sustainability of sorbent materials alongside lab-scale experiments and confirms that the right direction to produce new performant and sustainable adsorbent materials involves not only choosing wastes as starting materials, but also optimizing the consumption of electricity used for the production processes. The main results also highlight the need for precise data in LCA studies based on lab-scale processes and the potential for small-scale optimization to reduce the environmental impacts.

A Lab-Scale Experiment on the Spontaneous Combustion Behavior of Chronic Naturally–Oxidized Coal in Re-Mining Coal Mine

ABSTRACT Spontaneous combustion of coal in re-mining coal mine is a serious threat to the safety recovery of coal resources. In this paper, six coal samples, including two raw bituminous coal samples from the new mining working face and four oxidized bituminous coal samples from the re-mining working face, are selected. The pore structures, thermogravimetric properties, and spontaneous combustion characteristics of raw coal and oxidized coal are studied. The pore structures show that the surface of oxidized coals has more cracks and higher macropore volume and porosity as compared with raw coal. The thermogravimetric experiments demonstrate that the oxidized coal has a higher combustion rate and turns to the combustion reaction zone in advance. Moreover, the oxidized coals perform a better combustion property by showing a comprehensive combustion index of 6.7 × 10−9 min−2·°C−3 and 8.9 × 10−9 min−2·°C−3, higher than the raw coal of 4.0 × 10−9 min−2·°C−3. The spontaneous combustion characteristics show that the oxidized coal performs a greater rate of oxygen consumption and more oxidation products released than raw coal. The CPT of raw coal is higher than 157°C, while the CPT of oxidized coal is between 132°C and 140°C. The research results can provide a risk assessment method for coal spontaneous combustion in the re-mining coal mine, and provide guidance for avoiding the occurrence of coal fires.

Diesel removal in non-aqueous phase by fibres from Calotropis procera: kinetic, isothermal and sorption potential evaluation

ABSTRACT Calotropis procera fibres have been proposed for free-phase diesel removal in case of spillage into groundwater. For this, characterizations were carried out using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FEG-SEM), wettability and contact angle measurements. Sorption oil capacity, kinetic, isothermal and recycling behaviour were evaluated. For initial optimization of the oil sorption capacity, an experimental design (DOE) was applied, with the optimized condition being 60 g L−1 of diesel in water and 0.01 g of fibre. Then, the results clearly indicated that the fibres have a hydrophobic and oleophilic character, quickly reaching more than 71.43 g g−1 of diesel sorption, according to the adjustment (R² > 0.99) of the pseudo-second order and Langmuir models, governed by absorption mechanisms. It should also be noted that at the end of 8 reuse cycles, the fibre presented a total accumulated sorption capacity of about 252.6 g g−1 of diesel. Furthermore, a laboratory-scale experiment was carried out to remove diesel from groundwater in gas station areas, the fibre removed 98.55% to 99.97% of removal efficiencies were achieved of the free phase over time. Therefore, the material demonstrates excellent characteristics for removing diesel spills in groundwater due to its fast, high and stable removal capacity.

A low-cost, open-source gas flow meter for laboratory-scale bioreactors

Biogas production measurement is a fundamental aspect of anaerobic digestion research. Lab-scale experiments usually require devices capable of measuring low flowrates and low relative pressures. Despite the existence of multiple commercially available alternatives for such demands, each with particular advantages and limitations, researchers have often resorted to in-house developed systems. This inclination is motivated by cost savings and the potential for of customization to suit specific research needs. Those systems, however, are seldom reproduced beyond laboratory walls due to overly complex designs, limited component availability or unpublished software. In this work, we developed a fully open-source lab-scale biogas flow meter equipped with datalogging capabilities. Our approach relied on inexpensive, widely available electronic modules. The flow meter was calibrated, tested and validated in batch biogas production experiments, alongside a comparative assessment with a proprietary device widely used in the field. The semi-continuous gas meter presented a resolution of 7.45 ± 0.13 mL and maintained a stable pulse volume (under 2 % relative standard deviation) for flowrates ranging from 60 mL h−1 to 1120 mL h−1. The device was not sensitive to the evaporative loss of up to 7 mL of packing liquid, demonstrating its applicability to long-term experiments. The developed system was shown to be robust and reliable and can be easily reproduced, revised and enhanced in laboratories everywhere.

Unlocking the power of LiOH: Key to next-generation ultra-compact thermal energy storage systems

This study explores the potential of untapped lithium hydroxide (LiOH) as a phase change material for thermal energy storage. By overcoming the challenges associated with the liquid LiOH leakage, we successfully thermal-cycled LiOH in a laboratory scale experimentation, and observed its stability (>500 thermal cycles), without chemical decomposition. This step has never been performed to date. Its solid-to-liquid reversible transitions temperatures and related solidification/melting enthalpies values have been verified. Then, the first experimental characterization of LiOH's thermal properties shows unexpected values for its heat capacity, thermal conductivity and diffusivity, in contradiction with the few ones available in literature. This opens avenues for LiOH's applications for the storage of sensible and latent heat, as shown through the increased cycle efficiency potential of a thermal energy storage system if based on its energy storage capacity; up to six times more volumetric energy density compared to traditional Solar Salt-based systems used in the solar tower plant (4.5 GJ/m3 vs. 0.76 GJ/m3 over 1000 thermal cycles). Additionally, we observed a softening phenomenon that occurs inconsistently during heating, but which may account for its excellent melting properties and the interplay with other raw chemicals. This new insight contributes certainly to the underlying mechanisms in the synthesis of another promising heat storage material in development: the peritectic compound Li4Br(OH)3. This pioneering work suggests LiOH as a promising ultra-compact thermal energy storage material for filling the intermediary gap from current to next-generation solar power plants, although its large-scale application requires further investigation to achieve economic viability.

An experimental and numerical framework to assess the temperature distribution in complex He II-cooled magnet geometries

In the context of the High Luminosity upgrade of the Large Hadron Collider at CERN, a framework implementing experimental techniques and numerical analysis has been developed to systematically assess the temperature distribution in complex He II-cooled composite magnet geometries. The experiments are designed to measure the heat transfer coefficients in the magnet coil layers using coil samples in a stagnant superfluid helium bath. A numerical tool-kit has been developed to facilitate intensive parametric studies, in addition to estimation of helium content via a phenomenological model. The workflow of the tool-kit is built to handle complex geometries composed of different materials each with their temperature-dependent properties, at low computational cost. This framework has been validated with experimental data obtained from laboratory-scale experiments on impregnated coil samples, reported and discussed here. Three use cases for the developed numerical tool, with increasing levels of complexity, are presented and its results discussed.

Process integration and techno-economic assessment of crystallization techniques for Na2SO4 and NaCl recovery from saline effluents

Saline effluents containing primarily sodium chloride (NaCl) and sodium sulfate (Na2SO4) are generated from common salt production, tannery CETPs, textiles industries, desalination rejects, etc. In this work, experimental studies have been conducted for parametric evaluation of crystallization techniques for selective isolation of Na2SO4 and NaCl from saline effluent. Three crystallization approaches, i.e., evaporation-crystallization, cooling-crystallization, and antisolvent-crystallization, are assessed through parametric studies. A representative saline solution generated from a salt refinery unit is considered for the study. Lab-scale experiments were performed to determine the optimum process conditions for each crystallization process, and their performance was evaluated by estimating the separation efficiency. Chemical, P-XRD, and TGA analyses were performed to characterize the product composition, purity, and hydration state. For selective Na2SO4 recovery, cooling crystallization, and antisolvent crystallization were found suitable over evaporation crystallization. Subsequently, integrated process variants for cooling crystallization and antisolvent crystallization-based separation were developed. A techno-economic assessment (TEA) was performed to compare integrated process variants for the recovery of salts (Na2SO4 and NaCl) and establish the prospective towards commercialization. The parametric evaluation and TEA shows that the combined crystallization technologies can be potential approach to recover added-value products from saline effluents promoting waste to wealth notion.

Cultivation of a naturally resilient Chlorella sp.: A bioenergetic strategy for valorization of cheese whey for high nutritional biomass production

This study investigated Chlorella's capacity to treat cheese whey (CW) effluent and produce a high-nutritional value biomass, by using a systematic sequential experimental design. Physicochemical analysis of CW revealed its high pollution load, characterized by elevated levels of lactose, phosphorus, and nitrogen, as well as high turbidity due to the presence of whey solids. Screening experiments demonstrated that trace mineral addition and continuous air supply are essential factors for Chlorella biomass production in CW (>800 mg·mL−1). Furthermore, whey solids did not hinder Chlorella growth, with notable biomass production observed even in undiluted CW, demonstrating this microalga's ability to adapt metabolically to the complex environment. Laboratory-scale photobioreactor experiments confirmed Chlorella's ability to produce biomass in CW, outperforming controls (>800 mg·mL−1). Bioremediation potential assessment exhibited significant reductions in organic pollutants (>14 g·L−1 COD), nitrogen (>400 mg·L−1), phosphorus (>140 mg·L−1) and sodium (>650 mg·L−1). CW solids were also removed with Chlorella harvesting (>99 %). Harvested algal biomass was enriched with proteins (>40 g·100 g−1), polyunsaturated fatty acids (>9 % TFA) and pigments, offering potential applications in nutraceutical and pharmaceutical industries. Overall, this study highlights Chlorella's efficacy in CW treatment and biomass valorization, offering a sustainable solution for dairy wastewater management while producing valuable resources.