Stirring Speed Research Articles

Statistical optimization, kinetic modeling, and techno-economic analysis for the production of high molecular mass dextran using sugarcane industrial waste-molasses

This study focuses on the transformation of industrial wastes to wealth by utilizing treated sugarcane molasses (TCM) to produce dextran. The fermentation conditions for maximum dextran production were initially optimized using central-composite design in shake-flasks. The highest titer of dextran (60.0 ± 2.0 g/L) was obtained with optimized variables of 150 g/L substrate (TCM), 12.8 g/L yeast extract, 39.8 g/L K2HPO4, and 48 h fermentation time. Then, the profiles of dextran production, TCM consumption, and microbial growth were fitted by kinetic models to obtain the following kinetic parameters: 0.35 h−1 maximum specific growth rate (μmax), 0.48 g dextran/g substrate yield coefficient (Yps), 0.07 maintenance coefficient (ms), and 10.73 g product/g cell growth-associated constant (α). For determining the scale-up factors, the fermentation conditions were replicated in a 3 L fermenter at various stirring speeds (50–250 rpm), and a scale-up strategy based on constant P/V was used to predict the power consumption (1.88–285.51 W) for a pilot-scale of 2000 L working volume fermenter at various stirring speeds (10.8–54 rpm). The dextran produced was characterized using gel permeation chromatography to determine the molecular mass variations (3–4000 kDa) with fermentation conditions. The rheological variations of fermentation broth at different stirring speeds were also studied and related to the molecular mass of the dextran produced. Techno-economic analysis for dextran production explored a gross margin of 22.65 %, a return on investment of 16.80 %, and a pay-back time of 5.95 years.

An artificial intelligence approach to model and optimize biodiesel production from waste cooking oil using life cycle assessment and market dynamics analysis

Biodiesel has emerged as a viable alternative to fuel, offering a more sustainable and environmentally friendly energy option. The current study explores the modeling and optimization of biodiesel production from waste cooking oil using artificial intelligence and genetic algorithms. The study focuses on enhancing five process parameters: methanol-to-oil molar ratio, catalyst concentration, reaction temperature, reaction time, and stirring speed. The optimization of these parameters is complemented by a life cycle assessment to reduce environmental impact. The approach considers biodiesel yield, high heating value, and energy consumption as output variables, thereby advancing sustainable biodiesel production. The findings indicated that, under optimal conditions (methanol-to-oil ratio of 1:6.9, stirring rate of 500 rpm, reaction duration of 20 s, reaction temperature of 30 °C and catalyst concentration of 1), the transesterification process achieved the maximum biodiesel yield of 97.76 %. The optimization reached a low environmental impact in the production of biodiesel in an efficient way. Additionally, SWOT analysis helps to develop strategic methods that can enhance efficiency and increase competitiveness. The research suggests that, by optimizing the chemical process in biodiesel production, it is possible to achieve a high yield and high heating value of the biofuel, along with feasible environmental mitigation strategies.

Recovery of rare earths from rare earth molten salt electrolytic slag using alkali phase reconstruction method with the aid of external electric field

Rare earth molten salt electrolytic slag (RMES) has emerged as a promising secondary resource for rare earth elements (REEs). This study introduces an innovative leaching technique for extracting REEs from RMES under atmospheric conditions, employing an alkali phase reconstruction method followed by an acid leaching process. Additionally, the external electric field was employed to enhance the reaction. Under the optimal reaction conditions: NaOH initial concentration of 70 wt%, NaOH-slag mass ratio of 4:1, temperature of 160 °C, current density of 1000 A/m2, reaction time of 90 min, stirring speed of 300 r/min, HCl concentration of 4 mol/L, liquid-solid ratio of 15:1, and leaching time of 20 min, the leaching efficiencies of Nd and Pr reach up to 99.21% and 99.14%, respectively. Phase analysis indicates that the rare earth fluorides transform into rare earth hydroxides, significantly enhancing their solubility in acid solution. The imposition of an external electric field leads to pronounced disruption of the RMES surface, thereby promoting the formation of stable reactive oxygen species in the alkaline medium. This facilitates the decomposition of fluorinated rare earths and hastens the phase reconstruction, resulting in an enhanced leaching process. The achieved leaching efficiency with an external electric field is 37% higher than that without an electric field.

Supported liquid membrane with selective stripping for separative recovery of copper and zinc from plating wastewater

For separation and recovery of different but chemically similar metal from dilute wastewater with reduced process complexity and cost, a supported liquid membrane (SLM) system that utilizes a single carrier together with strip dispersion for selective stripping of coextracted metal ions was proposed to enable concurrent separation and recovery. This study aims to investigate the effectiveness of the proposed SLM system for separative recovery of copper and zinc from real plating wastewater. Solvent extraction experiments were conducted to understand the effect of feed pH and carrier concentration on organic phase migration to the aqueous phase. The effect of stirring speed on the SLM transport rate was studied using synthetic feed. Combined with the insights from our previous study, appropriate settings were identified and applied to the SLM system. The SLM system could recover 83.7% copper with 91.0% purity and 85.5% Zn with 99.3% purity from the plating wastewater in 30 h. The findings indicate the feasibility of using SLM with selective stripping for the concurrent separation and recovery of copper and zinc from a dilute aqueous waste stream predominantly containing these two metals.

Recovery of Cu from waste smelting slag through extraction with novel deep eutectic solvents (DESs)

ABSTRACT This study reports on the recovery of copper, zinc, and iron from the copper smelting slag (CSS) of Saindak Copper and Gold Project, Baluchistan, Pakistan using novel deep eutectic solvents (DESs) and Sulfuric acid. Sorbic acid, citric acid, and urea were each mixed with tetrabutylammonium chloride (TBAC) to prepare three DESs. Leaching experiments were performed in batch mode under a constant stirring speed of 300 revolutions per minute (rev min−1) and contact time of 2 h, under different liquid to solid ratios (L/S 1.5–3) and different temperatures (60–90°C). Results showed that the DES2 (TBAC & citric acid) recovered about 77% copper, 49% zinc, and 1% iron among other two prepared DESs at 3 L/S and 90°C. Sulphuric acid recovered 94% copper, 2% zinc, and 4.7% iron under the same conditions. The same DES also showed selectivity in the recovery of copper, as compared to iron.

Multi-drug extraction using octanol supported rotating cellulose paper disc (RPD) device from complex biological matrices: Fabrication and application in forensic case work

For the first time, a novel rotating paper disk (RPD) device to simplify the sample preparation process for the analysis of a broad spectrum of analytes with varying log Kow (i.e., 0.65–5.4) values is introduced.These analytes encompass diverse classes, including benzodiazepines (such as diazepam, chlordiazepoxide, flurazepam), barbiturates (such as barbital, allobarbital, phenobarbital), antihistamines (i.e., pheniramine, chlorpheniramine), antidepressants (such as fluoxetine, amitriptyline, venlafaxine), antipsychotics (like clozapine, chlorpromazine), opioids (i.e., tramadol) and z-drugs (such as zolpidem). RPD synergistically utilizes the adsorption capabilities of cellulose paper (solid substrate) in conjunction with 1-octanol supported onto the paper. In order to fabricate the RPD device, a magnetic bar was sandwiched between octanol supported cellulose paper layers. RPD was then directly immersed into the diluted biological samples (postmortem biological matrices i.e blood and urine) and allowed to rotate at 400 rpm for 30 min for optimum adsorption of target analytes. Subsequently, adsorbed analytes were back-extracted into 1 mL of methanol without any external diffusion process and finally determined by gas chromatography-mass spectrometry (GC-MS). Design of experiment-based optimization was performed using Box-Behnken design (BBD) for the optimization of significant factors of sample preparation such as pH of the sample, stirring speed, extraction time and ionic strength. Under the optimized conditions, the method was found to be linear in the range of 0.1–10 μg mL−1 for blood and urine samples. Limit of quantification (LOQ) for blood and urine samples were determined within the range of 0.084–0.099 and 0.060–0.078 μg mL−1, respectively. Intra-day and inter-day precisions were less than 6 and 10%, respectively. Good relative recoveries in the range of 50.4–98.2%, were obtained for the proposed procedure. Furthermore, the proposed method has been effectively applied in forensic toxicology case work. Additionally, the proposed method underwent evaluation for its whiteness and blueness using the RGB12 algorithm and BAGI software, respectively.

Sustainable synthesis of 2-ethyl hexyl oleate via lipase-catalyzed esterification: A holistic simulation and cost analysis study

Lipase catalyzed synthesis of fatty acid esters has recently attracted much attention as it represents a cleaner production route compared to the conventional energy intensive chemical method. In this study, the technical and economic viability of 2-ethyl hexyl oleate (2-EHO) synthesis by the catalytic esterification of oleic acid (OA) and 2-ethyl hexyl alcohol (2-EHA) in a stirred tank reactor using Novozym 435 (Candida antarctica lipase B) was investigated. A conversion rate of 91% was obtained by adopting the subsequent optimized parameters: 4% enzyme amount, 2 h reaction time, 4:1 M ratio of alcohol to fatty acid, 150 rpm stirring speed, and 60 °C temperature. The lipase operational stability study showed that enzymes can be used for 30 successive cycles without significant lose in activity. The use of Aspen Plus simulator enabled the development of a detailed process flow diagram, which significantly improved the understanding of this clean production method and assessed the overall costs. A holistic cost analysis revealed a production cost of $2109 per ton of 2-EHO, thereby yielding an approximate 28% profit margin relative to prevailing market rates. Rigorous financial assessments corroborated the project's viability, substantiating a net present value (NPV) of $14.7 MM, a return on investment (ROI) of 583.91% (plant life time = 15 years), projected Payback Period stands at 6 years, and an internal rate of return (IRR) of 23%. These results confirm the technical and economic feasibility of lipase catalyzed production of 2-EHO, highlighting its potential as an environmentally and profitable approach in the synthesis of fatty acid esters.

Custom-made spherical fluorescent tracer particles for laser Velocimetry Laboratory Experiments

This article introduces a method for creating custom-made spherical fluorescent particles tailored for fluid mechanics optical velocimetry laboratory measurements techniques such as Particle Image Velocimetry (PIV) and Particle Tracking Velocimetry (PTV) measurement techniques. The incorporation of the fluorescent dye Rhodamine B into the particle bulk significantly reduces direct light reflections and enhances particle detection when enlightened by a laser and using a band-pass filter on the optical measurement device. Furthermore, the study offers a clear guide for adjusting particle diameter by modifying various parameters such as the stirrer used, its stirring speed, the surfactant concentration, and the type of polymer. This allows for the customization of particles best suited for water multiphase flow characterization and transport studies. The resulting particles exhibit excellent sphericity, making them suitable for a wide range of fluid mechanics investigations, from small to large scale. Experimental validations, including size measurements, density assessments, emission spectra analyses, and applicability in a confined flow affirm the effectiveness of the proposed methodology by exhibiting a signal-to-noise ratio four to five times higher than fluorescent surface-stained and non-fluorescent particles.

A Novel, Dual-Initiator, Continuous-Suspension Grafting Strategy for the Preparation of PP-g-AA-MAH Fibers to Remove of Indigo from Wastewater.

The indigo dye found in wastewater from printing and dyeing processes is potentially carcinogenic, teratogenic, and mutagenic, making it a serious threat to the health of animals, plants, and humans. Motivated by the growing need to remove indigo from wastewater, this study prepared novel fiber absorbents using melt-blow polypropylene (PP) melt as a matrix, as well as acrylic acid (AA) and maleic anhydride (MAH) as functional monomers. The modification conditions were studied to optimize the double-initiation, continuous-suspension grafting process, and then functional fibers were prepared by melt-blown spinning the modified PP. The results showed that the optimum modification conditions were as follows: a 3.5 wt% interfacial agent, 8 mg/L of dispersant, 80% monomer content, a 0.8 mass ratio of AA to MAH, a 1000 r/min stir speed, 3.5 wt% initiator DBPH grafting at 130 °C for 3 h, and 1 wt% initiator BPO grafting at 90 °C for 2 h. The highest grafting rate of the PP-g-AA-MAH was 31.2%, and the infrared spectrum and nuclear magnetic resonance spectroscopic analysis showed that AA and MAH were successfully grafted onto PP fiber. This modification strategy also made the fibers more hydrophilic. The adsorption capacity of the PP-g-AA-MAH fibers was highly dependent on pH, and the highest indigo adsorption capacity was 110.43 mg/g at pH 7. The fiber adsorption capacity for indigo increased rapidly before plateauing with increasing time or indigo concentration, and the experimental data were well described in a pseudo-second-order kinetic model and a Langmuir isothermal adsorption model. Most impressively, the modified fiber adsorption capacity for indigo remained as high as 91.22 mg/g after eight regeneration and reuse cycles. In summary, the PP-g-AA-MAH fibers, with excellent adsorption-desorption characteristics, could be readily regenerated and reused, and they are a promising material for the removal of indigo from wastewater.

Development, modelling and optimization of process parameters on the tensile strength of aluminum, reinforced with pumice and carbonated coal hybrid composites for brake disc application

This study focuses on optimizing double stir casting process parameters to enhance the tensile strength of hybrid composites comprising aluminum alloy, brown pumice, and coal ash, intended for brake disc applications. Analytical techniques including X-ray fluorescence, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy were employed to characterize the composite constituents. The Taguchi method was utilized for experimental design and optimization to determine the optimal weight compositions of brown pumice and coal ash, as well as stir casting parameters (stirrer speed, pouring temperature, and stirring duration). Regression analysis was employed to develop a predictive mathematical model for the tensile strength of the hybrid composites and to assess the significance of process parameters. The optimized composite achieved a predicted tensile strength of 186.81 MPa and an experimental strength of 190.67 MPa using 7.5 vol% brown pumice, 2.5 vol% coal ash, a pouring temperature of 700 °C, stirrer speed of 500 rpm, and stirring duration of 10 min. This represents a 52.23% improvement over the as-cast aluminum alloy’s tensile strength. Characterization results revealed that brown pumice and coal ash contain robust minerals (SiO2, Fe2O3, Al2O3) suitable for reinforcing metal matrices like aluminum, titanium, and magnesium. Thermogravimetric and differential thermal analyses demonstrated thermal stability up to 614.01 °C for the optimized composite, making it suitable for brake disc applications.

Highly efficient and eco-friendly process for selective recovery of copper from waste printed circuit boards via pyrolysis and ammoniacal solvoleaching

This study proposes a process combining pyrolysis and ammoniacal solvoleaching to selectively recover Cu from waste printed circuit boards (WPCBs). Optimal pyrolysis conditions were determined by investigating parameters such as temperature, heating rate, N2 flow rate, holding time and particle size. Under the conditions: 500 °C temperature, 20 °C/min heating rate, 0.3 L/min N2 flow rate, 10 min time and +9.50 mm particle size, ∼25% of weight loss was obtained. The pyrolyzed mass underwent further physical separation process involving impact crushing, magnetic- and gravity separations to enrich metals into a concentrate. Copper in the resulting concentrate was selectively extracted using a one-stage ammoniacal leaching and solvent extraction process (ammoniacal solvoleaching), employing an oxime-based organic extractant, LIX 84-I with a small volume of NH4OH. Ammoniacal solvoleaching was optimized by considering parameters such as stirring speed, time, LIX 84-I concentration, volume of aqueous ammonia, temperature and pulp density. Under the following conditions: 500 rpm, 0.3/0.3/10 (g/mL/mL) of sample/NH4OH/LIX 84-I (0.8 M), 3 h time and 25 °C temperature, quantitative Cu dissolution was achieved after two-stage solvoleaching. Cu solvoleaching followed the Avrami model, with an activation energy of 28.95 kJ/mol in the temperature range 15–45 °C (298–318 K) for the mixed control mechanism. LIX 84-I could be recycled without loss of extraction performance. Cu concentration was further enriched during stripping stage using H2SO4. A flowsheet for the sustainable metal recovery from WPCBs was developed.

Optimisation of a Microwave Synthesis of Silver Nanoparticles by a Quality by Design Approach to Improve SERS Analytical Performances.

A major limitation preventing the use of surface-enhanced Raman scattering (SERS) in routine analyses is the signal variability due to the heterogeneity of metallic nanoparticles used as SERS substrates. This study aimed to robustly optimise a synthesis process of silver nanoparticles to improve the measured SERS signal repeatability and the protocol synthesis repeatability. The process is inspired by a chemical reduction method associated with microwave irradiation to guarantee better controlled and uniform heating. The innovative Quality by Design strategy was implemented to optimise the different parameters of the process. A preliminary investigation design was firstly carried out to evaluate the influence of four parameters selected by means of an Ishikawa diagram. The critical quality attributes were to maximise the intensity of the SERS response and minimise its variance. The reaction time, temperature and stirring speed are critical process parameters. These were optimised using an I-optimal design. A robust operating zone covering the optimal reaction conditions (3.36 min-130 °C-600 rpm) associated with a probability of success was modelled. Validation of this point confirmed the prediction with intra- and inter-batch variabilities of less than 15%. In conclusion, this study successfully optimised silver nanoparticles by a rapid, low cost and simple technique enhancing the quantitative perspectives of SERS.

Optimization and characterization of essential oil-loaded nanoemulsions for enhanced antiviral activity against tobacco mosaic virus (TMV) in tobacco plants

Tobacco mosaic virus (TMV) is a significant viral pathogen that infects various economically important crops, including tobacco, tomatoes, and cucumbers. The current study aimed to develop and optimize essential oil-loaded nanoemulsions using Response Surface Methodology (RSM) to enhance antiviral activity against TMV in Nicotiana tabacum plants. Essential oils from tea tree (Melaleuca alternifolia) and lime peel (Citrus latifolia) were chemically analyzed using gas chromatography-mass spectrometry (GC-MS). Terpinene-4-ol (70.92 %) and trans-isolimonene (33.82 %) were identified as the major components in tea tree and lime peel oils, respectively. RSM was used to optimize the nanoemulsion formulations based on oil concentration, hydrophilic-lipophilic balance (HLB), and stirring speed. Optimal tea tree oil (TTEO) and lime peel oil (LPEO) nanoemulsions were developed and characterized using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and particle size analysis. The antiviral efficacy of the optimized formulations was tested against TMV using RT-qPCR analysis and physiological measurements. TTEO nanoemulsions significantly inhibited TMV expression by 89.78 %, while LPEO nanoemulsions achieved a 42.22 % reduction after six days. Additionally, these essential oils (EOs) enhanced plant defense mechanisms by modulating the activities of phenylalanine ammonia-lyase (PAL) and peroxidase (POD), along with maintaining chlorophyll levels. This study demonstrates that TTEO and LPEO nanoemulsions offer promising eco-friendly antiviral agents for TMV management in tobacco plants. The research underscores the potential of essential oil-based formulations in mitigating viral infections in crops, providing a sustainable alternative to synthetic chemicals.

Concentrations Influence of Complexing Agents on the Physicochemical Properties of Chemical Bath Deposited n‐Type FeSxOy for Homostructure Solar Cell

A chemical bath deposition (CBD) is applied to deposit n‐type iron sulfide (FeSxOy) film on fluorine (F)‐doped tin oxide (SnO2)–FTO substrate. The duration, temperature, and magnetic stirrer's speed in CBD are 3 h, 75 °C, and 100 revolutions per minute. The influence of complexing agents’ concentration (≤200 mm)–acid (tartaric and lactic) on the physicochemical properties of film is studied. All films are n‐type semiconductors with large bandgap (2.95–3.58 eV) and contain high oxygen (≈56–83%). Scanning electron microscopy image shows the 50 mm tartaric acid film has a uniform and denser surface morphology. FeSxOy film with tartaric acid has lesser goethite and hematite peaks in X‐ray diffraction than lactic acid. The FeSxOy film with 100 mm lactic acid exhibits a slightly higher transmittance at ≈350–450 nm. The FeSxOy homostructure reveals average open‐circuit voltage (Voc) = 0.45 V, short‐circuit current (Jsc) = 0.0003 mA cm−2, fill factor =38%, and efficiency (η) = 0.57%.

An effective tandem leaching method for recovering precious metals from depleted ternary lithium-ion batteries

The increasing volume of spent ternary lithium batteries necessitates the development of an environmentally friendly and efficient recycling process tailored for these batteries. This paper introduces an innovative leaching system that employs oxalic acid and its derivative, Deep Eutectic Solvents (DES), as leaching agents, specifically designed to selectively recover Li and other valuable metals from the cathode materials of discarded ternary lithium batteries, Li(NixCoyMn1-x-y)O2 (NCM). These findings indicate that oxalic acid is capable of selectively leaching Li without the need for reducing agents, whereas DES effectively segregates and leaches other valuable metals. The optimal parameters determined through orthogonal experiments for the initial leaching stage included a solid-to-liquid ratio of 15 g L−1, leaching duration of 3 h, temperature of 75 °C, and stirring speed of 400 rpm, resulting in a Li leaching rate of 99.95%. In the subsequent step, DES enabled the precipitation of Ni and the leaching of Co and Mn within 2 h at 110 °C, achieving recovery rate of 99.88% for Ni, 98.1% for Co, and 90% for Mn, while also significantly optimizing the recovery conditions. This breakthrough may offer an environmentally benign and effective method for the selective recovery of Li and other valuable metals.

A hybrid adsorption / ultrafiltration membrane process for removal of Cs-137 from radioactive wastewater using natural clay adsorbent

The removal of radioactive cesium element (Cs-137) from wastewater is relatively challenging due to its high diffusion coefficient, short hydration radius, and the similarity between its chemical behavior to other alkali metals having high background concentrations, leading to a competition that reduces the removal efficiency of cesium (Cs-137). This study introduces an innovative treatment process using a submerged membrane adsorption hybrid system (SMAHS) using natural Iraqi clay minerals as adsorbents. The operational conditions were studied using the (SMAHS) continuous flow operation in stirred filtration mode experiments. The maximum operational conditions were achieved for the initial radioactivity concentration of Cs-137 at 7201.8 Bq/L, clay dose 1 g/L, the stirring speed at 700 rpm, pH =6, the transmembrane pressure (TMP) under 2 bar, and temperature at 25 °C. The SMAHS rejection percentage of Cs-137 was 93.6 % and the permeate flux was 105.6 L/m2.h at the best operational conditions. This study demonstrates that utilizing raw bentonite which is both environmentally friendly and locally available as an adsorbent in the SMAHS has proven its effectiveness for removing Cs-137 from wastewater. The hybrid method effectively immobilizes radioactive waste by converting it from liquid to solid state, leading to an extended and safer storage time.

Synthesis and morphology of Ag nanowires by fiber template method

The synthesis of traditional silver nanowires often uses a polyol method. There are many factors that affect the structure of silver nanowires, such as silver ion concentration, type and amount of reducing agent, oxygen concentration, stirring speed, temperature, and time. The synthesis conditions are harsh and difficult to replicate. In this paper, natural fibers and synthetic fibers were used as templates to assist the polyol reduction method to obtain silver nanowires with uniform structure. The effect of fiber types on the structure of silver nanowires were studied, including hemp fibers, wheat straw fibers, tobacco stem fibers, and polycarbonate fibers. Polycarbonate fibers induced the synthesis of silver nanowires with the highest aspect ratio, highest yield, and most uniform diameter distribution. The effect of polycarbonate fibers concentrations on the morphology and conductivity of silver nanowires were also studied. When the polycarbonate mass concentration was 8.5 × 10−4 g/mL, the aspect ratio of silver nanowires was the highest. The effect of polycarbonate fibers length (2 mm\\5 mm\\7 mm) on the morphology of silver nanowires were also studied. When the length of the template polycarbonate fibers was 7 mm, the length to diameter ratio and conductivity of the nanowires obtained are the best. Furthermore, the reaction kinetics of the reaction were studied via multiple sampling of silver nanowire reaction solutions and characterized by using UV–visible spectroscopy and scanning electron microscopy. The synthesis method of silver nanowires using fiber template is simple and fast, and can be used to synthesize silver nanowires with uniform diameter distribution on a large scale, thus solving the bottleneck problem of harsh synthesis conditions for silver nanowires. The resulting silver nanowires were blended with carboxymethyl cellulose to prepare conductive inks, which were coated on paper and cured at 180 °C for 30 min to achieve good conductivity.

Improvement of mechanochemical leaching of zinc oxide ore — Optimization of grinding parameters for basket grinder

The mechanochemical leaching (MCL) process presents promising potential for efficiently extracting zinc from zinc oxide ores. This study analyzed the effects of several grinding parameters, including the agitator type, grinding ball size and material, grinding ball addition, and stirring speed, on the zinc leaching. Among them, the agitator type affects the flow form and mass transfer rate of the solution, the grinding ball size and material affects the crushing effect of the mineral powder, the grinding ball addition affects the state of motion of the grinding ball, and the stirring speed affects the grinding effect of the grinding ball on the mineral powder, which in turn affects the extraction of zinc. Experimental results show that optimization of these grinding parameters results in higher zinc leaching rates at lower energy costs. Under optimal conditions, the zinc leaching rate can reach 86.02% through the optimized MCL process, which is 9.38% higher than the conventional leaching process. Analysis techniques, such as XRD, particle size analysis, SEM-EDS, and EPMA, were utilized to examine leaching residues. The leaching mechanism of MCL process is derived under mechanical activation to destroy the insoluble product layer of zinc oxide ores (such as gangue), expose the zinc containing components, change the physical and chemical properties (such as mineral structure, particle size, and specific surface area), and enhance the reactivity of zinc oxide ore, and enhancing zinc leaching. The optimized MCL process offers the benefits of a straightforward process, reduced energy consumption, and eco-friendliness. This process has vast potential in the development and utilization of low-grade refractory zinc oxide ores in the Lanping area.

Preparation of Microsponge Drug Delivery System (MSDDS) Followed by a Scale-Up Approach.

In 1987, Won invented the solid-phase porous microsphere (MS), which stores bioactive compounds in many interconnected voids. Spherical particles (5-300 μm), MS, may form clusters of smaller spheres, resulting in many benefits. The current investigation focussed on gel-encased formulation, which can be suitable for dermal usage. First, quasi-emulsion (w/o/w) solvent evaporation was used to prepare 5-fluorouracil (5 FU) MS particles. The final product was characterized (SEM shows porous structure, FTIR and DSC showed drug compatibility with excipients, and gel formulation is shear-thinning) and further scaled up using the 8-fold method. Furthermore, CCD (Central Composite Design) was implemented to obtain the optimized results. After optimizing the conditions, including the polymer (600 mg, ethyl cellulose (EC), eudragit RS 100 (ERS)), stirring speed (1197 rpm), and surfactant concentration (2% w/v), we achieved the following results: optimal yield (63%), mean particle size (152 µm), drug entrapment efficiency (76%), and cumulative drug release (74.24% within 8 h). These findings are promising for industrial applications and align with the objectives outlined in UN Sustainable Development Goals 3, 9, and 17, as well as the goals of the G20 initiative.

Analisis Pemanfaatan Limbah Abu Kelapa Sawit Sebagai Adsorben dalam Menurunkan Logam Besi (Fe) pada Air Asam Tambang

The aim of this research is to analyze the comparative ability of boiler ash and incinerator ash in reducing Fe metal levels in Acid Mine Water, analyze the effect of mass variations and pH variations of the POFA adsorbent and analyze the adsorption ability. The flow in this research is adsorbent activation, taking Acid Mine Water samples, testing the initial conditions of Acid Mine Water samples which include pH and Fe testing and the AAT adsorption experimental stage, acid mine water sample volume 250 ml for each experiment, stirring speed 300 rpm and contact time. for 3 hours with adsorbent masses used of 2.5g, 5g and 10g, and pH variations of 5, 7 and 9, data analysis stage of adsorption capacity data. Based on research results, boiler ash is better at adsorbing Acid Mine Water, the greater the POFA adsorbent mass has the ability to reduce Fe metal because the removal percentage is greater. The best pH for adsorption treatment is pH 7, namely neutral pH, the most optimal mass of adsorbent used is 10g with a pH value of 7. The regression value on the Langmuir Isotherm is higher than the Regression value on the Freundlich Isotherm, so the Langmuir Isotherm is better for find out how much adsorbate mass can be adsorbed by the adsorbent.