Sodium Hydroxide Concentration Research Articles

Niobium Metal–Organic Framework Is an Efficient Catalytic Support for the Green Hydrogen Evolution Process from Metal Hydride

Herein, the development of a niobium-based metal–organic framework (Nb-MOF) designed to serve as a catalytic support for the production of hydrogen (H2) from sodium borohydride (NaBH4) is reported. The Nb-MOF was synthesized via a solvothermal method using niobium ammoniacal oxalate (AmOxaNb) as the metal source and 1,4-benzenedicarboxylic acid (BDC) as the ligand. The resulting MOF was characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The characterization study confirmed the successful synthesis of Nb-MOF. The catalytic activity was optimized by examining five key factors: (i) platinum (Pt) and cobalt (Co) bimetallic compositions (ranging from 1:0 to 0:1 mmol), (ii) NaBH4 concentration (0.2, 0.3, 0.4, and 0.5 mol L−1), (iii) the Nb-MOF/Pt–Co catalyst dose (0.05, 0.10, 0.20, and 0.40 mmol), (iv) sodium hydroxide (NaOH) concentration (0.01, 0.05, 0.1, and 0.2 mol L−1), and (v) system temperature (293.15, 298.15, 303.15, 313.15, and 323.15 K). The optimal catalyst was identified as Nb-MOF supporting a Pt-Co bimetallic composition in a 0.4:0.6 mmol ratio, achieving a hydrogen generation rate (HGR) of 1473 mL min−1 gcat−1 and an activation energy of 19.2 kJ mol−1. Furthermore, this catalyst maintained its efficiency over 20 cycles, demonstrating significant potential as a sustainable solution for H2 evolution from NaBH4.

Pre-treated municipal solid waste bottom ash as alkali-activated mortar precursor

Pre-treated incinerator bottom ash was used as a precursor of alkali-activated mortars. Control mortars were produced using coal fly ash. Different combinations of alkaline activator were tested (sodium oxide/binder ratio (4%, 6%, 8%, 10% and 15%) and silicon dioxide/sodium oxide ratio (0, 0.5, 1.0, 1.5 and 2.0)) and the influence of these on the mortar's mechanical performance was evaluated. The mortars were tested in both fresh (for density and workability) and hardened states (for dry density, compressive and flexural strengths and modulus of elasticity) after 7, 28, 91 and 182 days. The first stage of work was precursor pre-treatment in a sodium hydroxide solution to prevent the expansion of fresh specimens due to the reaction of aluminium with the alkaline activator. The pre-treatment was effective in preventing excessive hydrogen gas generation during setting, leading to dimensional stability and improved strength. Different optimum sodium oxide contents were observed after 28 days (i.e. 15% for fly ash specimens and 8% for bottom ash specimens). The results of a simplified life-cycle assessment showed that such mixes exhibited lower overall carbon dioxide emissions when compared with cement-based counterparts. However, this trend was reversed with increasing contents of sodium hydroxide and sodium silicate.

Evaluating sisal fibers as an eco-friendly and cost-efficient alternative to cotton for the Moroccan absorbent hygiene and textile industries

The Moroccan textile and hygiene industries face challenges related to the cost and availability of imported cotton fibers, prompting the exploration of alternative and sustainable solutions. The goal was to replace cotton, which presented a significant challenge for the sector, while maintaining its quality properties. This study aimed to replace the imported cotton fibers in Morocco with sisal fibers, a locally available, cheaper, and durable product that exhibits satisfactory physicochemical properties. To achieve this, sisal fibers were treated with different concentrations of sodium hydroxide (NaOH), sodium chlorite (NaClO₂), and hydrogen peroxide (H₂O₂). Analytical techniques, including Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), Optical Microscopy (OM), and X-ray Diffraction (XRD), were used to assess both sisal and commercial cotton fibers. Laboratory tests, such as pH measurements, water absorption, flammability, and degumming rate, were conducted to evaluate and compare their properties. Among the sisal samples analyzed, those treated with 10 % by weight (wt) NaOH and bleached with NaClO₂ showed satisfactory results. These fibers exhibited a compliant pH, a chemical structure similar to cotton, reduced fiber size, a type I crystal structure with a 0.36 crystallinity index, and improved thermal stability. Additionally, they presented a whitish appearance, softness similar to cotton, good fluid absorption capacity, and flame resistance. This study concluded that cotton fibers can be substituted with sisal fibers in the textile and hygiene industries. Further comprehensive analyses could expand the applicability of sisal fibers to additional sectors.

Effect of Mercerization on the Properties of Cellulose Fiber and Cellulose Hydrogel Extracted from Pineapple Leaf Fiber

AbstractThis study investigated the effects of alkaline treatment on the pineapple leaf fiber (PALF) cellulose extraction and the properties of cellulose hydrogel. PALF was treated with different concentrations of sodium hydroxide (NaOH) (2 to 10 wt %) and at room temperature (RT) and 80 °C. Then, extracted cellulose was then dissolved in N,N’‐dimethyl acetamide (DMAc)/lithium chloride (LiCl) solvent system and formed into hydrogel by phase inversion method. The Fourier transform infrared spectra shows the peak disappearance at 1606 cm−1 proves that lignin was removed starting from 6 and 4 wt % NaOH at RT and 80 °C, respectively. Higher NaOH concentrations treatment increased thermal stability and the crystallinity (71 to 79 %) of the fibers. Higher NaOH concentration and treatment temperature enhanced cellulose extraction from PALF, leading to more physical crosslinking during hydrogel formation. High amount of cellulose extracted decreased the hydrogel's swelling equilibrium and increased the gel fraction. The highest transmittance (87.8 %) and the lowest intensity of absorbance (at 280 nm corresponding to lignin) were obtained by the hydrogel prepared with PALF treated with 8 wt % NaOH at 80 °C. Clearly, this research findings provide new insights into optimizing cellulose extraction using alkaline treatment specifically for cellulose hydrogel formation.

An investigation of the mechanical strength, environmental impact and economic analysis of nano alkali-activated composite

The current study explores both the mechanical strength and life cycle assessments of fly ash (FA)-based alkali-activated concrete (AAC) with/without colloidal nano-silica (NS) addition at high and low molar concentrations of sodium hydroxide in the activator fluid (12 M and 3 M). The cradle-to-gate approach is used to establish the system boundaries for life cycle assessments (LCA). The environmental impact of AAC (with/without NS) and conventional cement concrete (CC) mixtures was determined using the ReCiPe midpoint and endpoint approaches across various impact categories. The AAC mixes with and without NS addition reduce greenhouse gas (GHG) emissions by 30 % and 25 % with respect to CC mix, respectively. Within the majority of impact categories, sodium silicate and sodium hydroxide production are the primary contributors, accounting for up to 91 %. However, in water depletion, global warming potential, and fuel depletion, the overall contribution is as high as 65 %. Also, the AAC mix with and without NS addition consumes 34 % and 14 % less electricity during its production with respect to the CC mixture. The CC mixes have almost 70 % more ecological damage and approximately 30 % more health risk than AAC with and without NS. However, the NS-modified AAC shows 20 % lower ecological and health risks than AAC without NS. The effect of resource scarcity on NS modified AAC is 50 % less than that of other mixes, including both AAC mix without NS and CC mix. In comparison to AAC without NS, the NS modified AAC demonstrates an 18 % reduced impact on resource scarcity. Finally, cost analysis demonstrates that AAC with NS is 16 % less expensive than CC, while AAC without NS is 26 % cheaper than CC. AAC containing 6 % NS inclusions exhibits environmental and economic benefits in addition to its enhanced mechanical performance, indicating its potential for widespread practical usage.

Evaluating Alkali Activation in Magnesium Slag Carbonization and Its Mechanism

In recent years, magnesium slag has been used as a raw material for solid waste treatment using the carbonization method and has proven to be promising in reducing carbon emissions. In this study, the alkali activation reaction was introduced to promote the carbonization of magnesium slag. The resulting mechanical properties, microstructural attributes, and carbonization mechanism were studied by varying the sodium hydroxide content, temperature, and carbon dioxide concentration during the reaction process. The results showed that the amounts of calcium hydroxide, C-S-H, and calcium carbonate in the reaction products increased with the sodium hydroxide content, which enhanced the compressive strength of the composite. However, it does not influence the carbonization mechanism with the increasing reaction temperature, which only elevates the reaction rate. With the increase in the carbon dioxide concentration during alkali activation, the carbonization reaction is dominated by the amount of CO2 dissolved in the reaction medium, and the carbonization mechanism is changed. Thus, a significant decrease in the calcium hydroxide content and a sharp increase in the calcium carbonate content in the products occurred, which significantly improved the compressive strength of the resulting magnesium slag composite. Among them, the maximum compressive strength is 6.83 MPa.

Pretreatment and dyeability analysis of cotton and novel Bauhinia vahlii fiber

The textile industry is witnessing a paradigm shift towards sustainable materials, prompting the exploration of novel natural fibers as alternatives to synthetic fibers to meet environmental standards and address the growing demand for eco-friendly and sustainable products. Different natural fibers possess varied properties and are suitable for numerous applications in conventional and technical textiles. The coloration of these textile materials is an important aspect of conventional textiles, which starts with the pretreatment of the material. This study introduces a novel blend of cotton and Bauhinia vahlii fiber, a lesser-known natural cellulosic fiber with promising textile properties, and evaluates its pretreatment outcomes and dyeability characteristics. The study employs a systematic approach to pretreat the cotton and Bauhinia vahlii fiber blend (cotton: Bauhinia vahlii fiber 70:30) in a single bath using a conventional combined scouring bleaching process. The pretreatment process is carried out two times with varied sodium hydroxide (NaOH) and hydrogen peroxide (H2O2) concentrations for different processing times at 90 °C to assess the component fibers’ whiteness index, union bleaching balance, and weight loss percentage under diverse pretreatment conditions. Each time, 50% of the chemicals were used and continued for half of the processing time. The dyeability of the treated fibers is analyzed by dyeing the same in a single bath using amron bright red HF2R bifunctional reactive dye in varied shade depths (1%, 3%, and 5%) and fiber blend ratios (cotton: Bauhinia vahlii fiber 100:0, 90:10, 80:20, 70:30, and 0:100) to assess the color strength, union dyeing balance, and fastness properties. The maximum whiteness was achieved with 6 g per liter (gpl) of NaOH and H2O2 and at a processing time of 150 min with a whiteness index of 80.46 and 54.34 of cotton and Bauhinia vahlii fiber, respectively, with a union bleaching balance of 1.48. The dyed fibers’ colorimetric results confirm that Bauhinia vahlii fiber gives higher color strength than cotton fiber, irrespective of shade depth and blend ratio. The union dyeing balance of 1.2 was achieved at 5% shade depth with a 70:30 cotton Bauhinia vahlii fiber blend. This research contributes to the conventional textile field by introducing a sustainable fiber blend that reduces reliance on synthetic fiber and opens new avenues for utilizing Bauhinia vahlii fiber in conventional textile manufacturing.

Optimizing alkali-activated clay with rubber waste for sustainable earthen bricks: A comprehensive study

This study explores the potential of optimizing alkali-activated clay with rubber waste to create sustainable earthen bricks. The research addresses the environmental challenges associated with traditional cement-based construction materials by incorporating locally sourced calcined clay and recycled rubber tire waste. The experimental program involves testing different proportions of sand with calcined clay, varying sodium hydroxide (NaOH) concentrations, and integrating rubber content. The aim is to develop a material that balances environmental sustainability with improved mechanical and durability properties. The mechanical and microstructural properties of the resulting materials were evaluated through compressive and flexural strength tests, wetting and drying cycles, and advanced analysis techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that while the inclusion of rubber enhances certain properties such as reducing the unit weight and Structural Integrity During Wet-Dry Cycles, it adversely affects compressive and flexural strengths. This study highlights the importance of optimizing the balance between durability and mechanical strength to develop effective and sustainable construction materials.

Response Surface Design Models to Predict the Strength of Iron Tailings Stabilized with an Alkali-Activated Cement

Tailing storage facilities are very complex structures whose failure generally leads to catastrophic consequences in terms of casualties, serious environmental impacts on local biodiversity, and disruptions in the mineral supply. For this reason, structures at risk must be reinforced or decommissioned. One possible option is its reinforcement with compacted filtered tailings stabilized with binders. Alkali-activated binders provide a more sustainable solution than ordinary Portland cement but require an optimization of the tailing–binder mixture, which, in some cases, can lead to a substantial experimental effort. Statistical models have been used to reduce the number of those experiments, but a rational design methodology is still lacking. This methodology to define the right mixture for a required strength should consider both the mixture components and in situ conditions. In this paper, response surface methods were used to plan and interpret unconfined compression strength test results on an iron tailing stabilized with alkali-activated binders. It was concluded that the fly ash content was the most important parameter, followed by the liquid content and sodium hydroxide concentration. From the obtained results, several statistical models were defined and compared according to the definition of a strength prediction model based on a mixture index parameter. It was interesting to observe that models with the porosity cement index still provide reasonable adjustment even when different tailings’ water contents are considered.

Synthesis and characterization of etherified cationic starch flocculant derived from Manihot esculenta peel with varying degrees of substitution

Cationic Manihot esculenta (ME) peel starch was synthesized through etherification method using 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC) as cationizing monomer. The optimization of the main factors influencing the degree of substitution (DS) was conducted using central composite design (CCD) and response surface methodology (RSM). The factors assessed include CHPTAC concentration, catalyst sodium hydroxide (NaOH) concentration, and reaction time. The DS values of the cationic starches were obtained between 0.39 and 0.99. The maximum DS value was up to 0.99 at 0.615 mol/L of CHPTAC, 30 % (w/v) NaOH, and a reaction time of 5 h. The finding based on the optimization using RSM reflected that CHPTAC and NaOH concentrations are the key variables determining the DS value, while reaction time has a negligible impact on the etherification process. Furthermore, the chemical composition, morphology, and structure of the cationic ME peel starch were characterized by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and nuclear magnetic resonance spectroscopy (1H NMR). It was confirmed that the modifying monomers penetrated the surface layer of the starch granules and attached to the starch backbone.

Strength, durability, and toxicity characteristics of water treatment sludge based geopolymers for subgrade application

This study examined the strength, durability and toxicity characteristics of geopolymer made from water treatment sludge (WTS) using fly ash (FA) and ground granulated blast furnace slag (GGBS) as binding materials for the subgrade application. The mechanical properties of WTS-FA-GGBS geopolymers were assessed considering various parameters such as binder proportions, curing period, curing condition, Sodium silicate (SS) to Sodium hydroxide (SH) ratio (i.e. SS/SH), and Sodium hydroxide (NaOH) concentration. The results showed that increasing binder proportions, NaOH concentration, and curing period positively impacted the strength of the WTS-FA-GGBS geopolymer. The unconfined compressive strength (UCS) of the geopolymer samples with an SS/SH ratio of 2.5 showed higher compressive strength than those at an SS/SH ratio of 1. WTS-FA-GGBS geopolymers cured at 100°C showed increased UCS values after 1 to 3 days, but strength decreased after 7 days due to a faster geopolymerisation reaction, resulting in excessive moisture loss and microcracks in the geopolymerized samples. The study also found that all the geopolymer samples met the minimum strength criteria for cement-stabilized mix with a maximum mass loss of 8.17 % are well within the specified limits (<14 %) as per IRC:37–2018. The California Bearing Ratio (CBR) values of WTS-FA-GGBS geopolymers, which range from 41.11 % to 260.32 %, surpass the minimum criteria for cement stabilized subgrade or subbase material, as specified by IRC: SP:89–2010. Additionally, the changes during geopolymerization were confirmed by FESEM, EDS, and XRD analysis. The toxicity characteristic leaching procedure (TCLP) test results showed that the amounts of heavy metals in the geopolymer leachate were within the USEPA-mandated limits.

Revolutionizing Waste Management: Solidification of Landfill Leachates Using Alkali-Activated Slag

AbstractLandfill leachate is a highly hazardous effluent characterized by a high concentration of recalcitrant pollutants, presenting a significant environmental challenge. This study investigated the solidification of landfill leachate contaminants using sodium hydroxide-activated Granulated Blast Furnace Slag (GBFS). The stability of the resulting geopolymer was evaluated through unconfined compressive strength and leaching tests. Optimal curing conditions were identified as 7 days at a sodium hydroxide concentration of 12 M, achieving an unconfined compressive strength of 45.738 MPa at a liquid-to-solid ratio of 15%. A linear relationship was observed between the liquid-to-solid ratio and flow workability, with maximum flow workability evidenced by an average diameter of 242 mm at a liquid-to-solid ratio of 0.25. However, a minimum liquid-to-solid ratio of 0.15 was necessary to obtain a workable mortar. The produced geopolymers were characterized using X-ray Fluorescence (XRF) for mineralogical analysis, Scanning Electron Microscopy (SEM) for morphological examination, and the Toxicity Characteristic Leaching Procedure (TCLP) for leaching tests. The findings demonstrated the successful solidification of landfill leachate using GBFS geopolymer. The leachability tests revealed that the geopolymer did not release metals in concentrations exceeding the allowable limits set by the United States Environmental Protection Agency (USEPA), indicating effective encapsulation of the pollutants within the geopolymer matrix. Furthermore, the resultant geopolymer brick is eco-sustainable and can be classified as a green construction material.

Alginate functionalized sugarcane cellulose-based beads to improve methylene blue adsorption from aqueous solution

The study was carried out with the goal of synthesizing composite bead of cellulose, chitosan functionalized by sodium alginate using as an efficient and applicable adsorbent for methylene blue removal. Fabricating parameters of the material synthesis process like cellulose mass, sodium hydroxide concentration, immersing time and sodium alginate concentration were assessed in detail. The dye adsorption performance in water under the influence of pH, contact time, dye initial concentration, the material mass, shaking speed, temperature was also thoroughly evaluated. The results of advanced analyses showed that the beads were successfully synthesized with a rough surface and mesoporous structure. The adsorption isotherm and adsorption kinetics of dye adsorption process exhibited that the process was consistent with the Freundlich adsorption isotherm and the pseudo-second-order kinetic model, indicating a favorable physical adsorption process with multilayer of the dye on the adsorbent surface. The intra-particle diffusion model showed the strong dye adsorption by the beads occurred during the first two and half hours. The adsorbent could maintain its adsorption performance of 86 % for three times of regeneration. Finally, this study provided a recyclable and effective adsorbent for dyes separation from water.

The production and biological activity of fungal chitosan from the mycelial waste of Rhizomucor miehei

In this study, waste biomass of industrial enzyme producer Rhizomucor miehei was used as an alternative source for fungal chitosan production. Fungal chitosan was obtained from mycelial waste at the deproteinization and deacetylation stages at different temperatures and times of alkali and acid treatment with different concentrations of sodium hydroxide (1–3 N) and acetic acid (2–4 %), respectively. High chitosan yield (70.6 mg/g) was reached at the optimized conditions when the concentration of NaOH (3 N), the deproteinization time (20 mins) and temperature ( 95℃), the concentration of acetic acid (4 %), the deacetylation time (6 hrs) and temperature (85℃). The fungal chitosan with a molecular weight of 14 kDa showed a deacetylation degree of 78 %. The XRD pattern showed two peaks at 2θ values of 9° and 19°. The antimicrobial activity of the fungal chitosan showed broad spectrum at low concentrations (125–250 µg/mL) against the test microorganisms. As wound healing activity, after five days post-scratching, the HaCaT cells cultured in the presence of fungal chitosan demonstrated a notable 57 % increase in migration rate. These findings underscored the efficacy of the produced fungal chitosan, highlighting its promising biological activities. This is the first report to evaluate the use of waste Rhizomucor miehei biomass as alternative source for chitosan.

From Field to Pharmacy: Isolation, Characterization and Tableting Behaviour of Microcrystalline Cellulose from Wheat and Corn Harvest Residues.

A lack of strategies for the utilization of harvest residues (HRs) has led to serious environmental problems due to an accumulation of these residues or their burning in the field. In this study, wheat and corn HRs were used as feedstock for the production of microcrystalline cellulose (MCC) by treatment with 2-8% sodium hydroxide, 10% hydrogen peroxide and further hydrolysis with 1-2 M hydrochloric acid. The changes in the FT-IR spectra and PXRD diffractograms after chemical treatment confirmed the removal of most of the lignin, hemicellulose and amorphous fraction of cellulose. A higher degree of crystallinity was observed for MCC obtained from corn HRs, which was attributed to a more efficient removal of lignin and hemicellulose by a higher sodium hydroxide concentration, which facilitates the dissolution of amorphous cellulose during acid hydrolysis. MCC obtained from HRs exhibited lower bulk density and poorer flow properties but similar or better tableting properties compared to commercial MCC (CeolusTM PH101). The lower ejection and detachment stress suggests that MCC isolated from HRs requires less lubricant compared to commercial MCC. This study showed that MCC isolated from wheat and corn HRs exhibits comparable tableting behaviour like commercial sample, further supporting this type of agricultural waste utilization.

Characterisation of alkali-treated novel cellulosic fibres derived from Dombeya Buettneri plant as a potential reinforcement for polymer composites

ABSTRACT The present study evaluates the influence of alkali treatment using 2, 4, and 8 wt.% sodium hydroxide concentration solutions on novel cellulosic fibres manually extracted from the bark of dombeya buettneri plant (DBF). Alkali-treated fibres were characterised through physical and mechanical properties determination, Fourier transform infrared spectroscopy, X-ray diffraction, quantitative chemical analysis, thermogravimetric analysis, and scanning electron microscopy. Quantitative chemical analysis revealed a significant increment in cellulose content, reaching 67 ± 1.7% in DBF treated with 4 wt.% NaOH solution, accompanied by substantial reductions in lignin and hemicelluloses as confirmed by FTIR spectroscopy. XRD analysis showed an improved crystallinity index of 80% and crystallite size of 2.64 nm for 4 wt.% alkali-treated DBF. Additionally, 4 wt.% alkali-treated fibres yielded peak values of breaking force (40 N) and breaking tenacity (181 cN/Tex). SEM analysis confirmed enhanced surface roughness post-treatment, an indication of enhanced fibre/matrix interlocking during composite fabrication, whereas TGA analysis reported improved thermal stability post-treatment. EDX analysis confirmed that the C/O ratio is proportional to alkali solution concentration, indicating effective removal of non-cellulosic contents. In conclusion, treating DBF with 4 wt.% NaOH concentration improves their physical, mechanical, and chemical properties, suggesting their potential for polymer composite applications.

Enhanced Saccharification Yield of Alkali Pretreated Sugarcane Bagasse Utilizing Customized Cellulase Cocktail from Trichoderma harzianum and Trichoderma viride

The experiment was conducted during 2023 at Bioenergy Laboratory, Department of RBEE, College of Agricultural Engineering and Technology, CCSHAU, Hisar, Haryana, India. Compositional changes in sugarcane bagasse subjected to varying concentrations of sodium hydroxide (0.3% to 1.2%), revealing significant increases in glucan content (from 37.13% to 53.81%) alongside decreases in xylan, acid-insoluble lignin, acid-soluble lignin, ash, and other extractives. These changes were validated using microscopic technique SEM, confirming the efficacy of the pretreatment process. The utilization of a customized cellulase cocktail derived from Trichoderma harzianum and Trichoderma viride holds significant promise in enhancing the saccharification from alkali-pretreated sugarcane bagasse. This study investigates the synergistic effects of cellulase enzymes produced by these fungi on the hydrolysis of lignocellulosic biomass. The enzymatic hydrolysis process is optimized by varying enzyme dosages, reaction conditions, and incubation times to maximize the release of fermentable sugars. Results indicate a substantial improvement in saccharification efficiency with the customized cellulase cocktail, highlighting its potential for sustainable biofuel production. The pretreated sugarcane bagasse, when saccharified with Trichoderma harzianum and Trichoderma viride individually, released 254.43 mg g-1 and 325.53 mg g-1 of reducing sugars, respectively, after 40 h of incubation. In contrast, the combined enzymatic cocktail achieved a substantial increase in glucose yields (345.12 mg g-1) at 40 h, showcasing the synergistic effect of the combined enzymatic activity. This research contributes to advancing bioconversion technologies for utilizing lignocellulosic biomass resources efficiently and economically, thus addressing key challenges in sustainable energy production.

Desalination of mother liquor generated from the precipitation of lithium carbonate during the recycling of retired lithium ion battery

Generally, hydrometallurgy process is adopted in factory to recover valuable metal from anode materials in lithium ion battery. The mother liquor generated from the precipitation of lithium carbonate in this process is often managed by evaporative crystallization process which is high energy-consuming and expensive. The methodology employed in this research involves pretreatment and bipolar membrane electrodialysis to partition salts within the mother liquor into acids and bases, thereby achieving cost savings. The findings reveal that a significant 76.5 % reduction in COD is achievable through the application of potassium permanganate and activated carbon in the treatment of the mother liquor. Subsequently, the treated mother liquor can be transfer to electrodialysis process for further treatment. During this process, desalination of the mother liquor occurs, leading to the decomposition of sodium sulfate into sulfuric acid and sodium hydroxide. Analysis of the experimental data reveals that optimizing the initial concentrations of sulfuric acid and sodium hydroxide within the acid and alkali collection chambers, along with the application of elevated electric current density and maintaining a high pH value of the mother liquor, yields improvements in current efficiency and concomitant reductions in energy consumption. Under optimal conditions, the current efficiency of acid and alkali preparation is 52.53 % and 62.12 % respectively, along with energy consumption of acid and alkali preparation is 8.68kWh/kg and 8.99kWh/kg respectively. The pretreatment and bipolar membrane electrodialysis process is low-energy consumption and inexpensive, facilitating a reduction in processing expenses to $6.659 per ton of mother liquor.

Modeling and Optimizing the Alkaline Treatment Process to Enhance the Date Palm Fibers’ Tensile Mechanical Properties Using RSM

ABSTRACT This study aims to enhance the mechanical properties of date palm fibers (DPFs) by implementing a targeted treatment technique. The response surface methodology (RSM) is utilized for modeling and optimizing. The study seeks to identify the optimal Alkaline treatment settings for improving the mechanical properties of DPFs by carefully analyzing parameters such as average diameter, time, and NaOH concentration. The analytical results offer valuable insights into the possible use of DPFs in many engineering applications, contributing to the industrial advancement of sustainable and eco-friendly materials. The experimental findings are analyzed using a full-factorial design (43), incorporating analysis of variance and RSM. Combining RSM and desirability function is used to get the best mechanical properties, including stress, strain, and Young’s modulus. The model appropriateness is evaluated by analyzing residual values. The findings suggest that the sodium hydroxide concentration (%NaOH) has the most significant impact on strain (11.63%), stress (12%), and Young’s modulus (11.72%) besides the time t (h) also significantly influences 6.01%, 6.26%, and 5.79% strain, stress, and Young’s modulus, respectively.

Synthesis of copper oxide (CuO) via coprecipitation method: Tailoring structural and optical properties of CuO nanoparticles for optoelectronic device applications

Oxide-based nanoparticles have been studied extensively due to their unique optical and passivation properties, which are significantly distinct from those of bulk materials. The present study aimed to synthesize copper oxide nanoparticles through the co-precipitation method. The adequate substitution of sodium hydroxide (NaOH) into CuO is analyzed by different characterizations, i.e., X-ray diffraction (XRD), Scanning Electron Microscope (SEM), UV–visible spectroscopy (UV–visible), Fourier transform infrared (FTIR), and EDX. The X-ray diffraction spectra indicate that the prepared copper oxide nanoparticles were crystalline, nano-sized, and highly pure. The SEM micrographs showed that nanoparticles were spherical at lower contents of NaOH, while at higher contents, agglomeration of nanoparticles occurs, and the grain size changes. The decreased optical bandgap of the nanoparticles was observed due to different concentrations of sodium hydroxide. The crystalline size and strain values were also determined through the Williamson-Hall method. The compressive micro-stain in CuO materials confirms the negative slope value of the line fit in the W–H Plot. From this study, we concluded that synthesized CuO NPs have the potential to combine CuO materials with antireflecting films for improved optical performance in optoelectronic devices, precisely current density properties.