Dissolution Efficiency Research Articles

Graphitized carbon encapsulated Co anode electrochemically activating persulfate for sulfamethoxazole degradation

The excessive use of antibiotics like sulfamethoxazole (SMX) is causing environmental pollution and endangering human health and the ecosystem. Using transition metals as catalysts to activate persulfate (PS) can effectively degrade the organic pollutants in the advanced oxidation process (AOP). However, the high dissolution of the transition metals leads to poor stability, low efficiency in pollutant degradation, and secondary pollution. In this work, a graphitized carbon encapsulated Co (Co@EC) anode is developed for electrochemically activating peroxymonosulfate (PMS) to degrade SMX. It is found that the synergistic effect of Co@EC, PMS, and current significantly enhances SMX degradation. Under optimal conditions (current density of 5 mA cm−2, pH of 9, and PMS concentration of 0.25 mM), the Co@EC anode can completely remove 10 μM of SMX in 9 min, a much higher efficiency compared to processes without PMS, Co, or current. The rapid reaction kinetics (6.69×10−1 min−1) at optimal conditions are associated with the two main active species of 1O2 and O2•− during electroactivation. Furthermore, the Co@EC anode maintains high degradation efficiency and low dissolution after repeated cycling tests due to its structural stability. These findings provide new insights and strategies for developing stable catalysts.

Electrochemical dissolution of titanium under alternating current polarization to obtain its dioxide

Abstract The titanium electrode was polarized under the influence of alternating current (AC) at 50 Hz. The current density was varied between 100 and 5,000 A m−2. Initially, the titanium electrode oxidized, and then, titanium oxides were reduced during the cathodic half-cycle of the AC. When the cathodic half-cycle changes to the anodic half-cycle, titanium is oxidized to the trivalent state: Ti − 3 e ̄ → Ti 3 + {{\rm{Ti}}-3{\rm{e}}{\rm{̄}}\to {\rm{Ti}}}^{3+} . The direction of the AC changes depending on its frequency, causing the processes occurring on the electrodes to be periodically repeated. The current efficiency of the titanium electrode dissolution depends on the sulfuric acid concentration and electrolyte concentration, reaching up to 63.4% under optimal conditions. Bipolar electrodes were used during AC electrolysis. It was found that the decrease in the mass of titanium electrodes increases almost linearly at first, from 400 to 1,600 A m−2, and then more intensively within the current densities from 1,800 to 2,500 A m−2. It was shown that when using a bipolar electrode, the total mass loss of the electrodes is 1.38 times greater than the total mass loss during polarization without a bipolar electrode. The composition of the titanium dioxide obtained as a result of electrolysis was identified using physico-chemical analysis methods.

Pharmaceutical quality of dispersible diclofenac tablets in the Saudi market

The fundamental objective in developing any drug delivery approach is to achieve effective and safe therapy. Medications classified as generics are those that contain the same active ingredients and have the same quality as the reference medications. Several generic drugs are available on the market, all at a reasonable cost. In this study, the quality of Three generic brands of diclofenac dispersible tablets available in the Saudi market was assessed, namely: G1 and G2, and G3.Except for the borderline performance of one generic formulation (G3), all formulations passed in vitro quality tests according to the United States Pharmacopoeia. According to the US Pharmacopoeia, every generic formulation passed in vitro quality tests, except for one generic formulation (G3) that performed inconclusively. All brands showed low weight variation, minimum weight loss in the friability test, and a rapid dispersion time of around 5 s. The chemical potency results demonstrated that all three brands complied with United States Pharmacopeia (USP) specifications, typically falling between 90% and 110% of the labeled amount. G1 and G2 passed the content uniformity test in their first attempt. G3 initially failed the content uniformity test but passed upon retesting with additional samples. G1 and G2 tablets passed the USP Acceptance criteria in stage one, and G3 tablets met the requirements in stage two. G1 showed the highest DE (%78.83), followed by G2 (%72.23), and G3 (%67.50). The G1 dissolution data, which showed the highest dissolution efficiency, were used as the reference product to calculate the similarity factor (f2 (ratio. G1 (Reference) and G2 with an f2 of (58.3) have similar dissolution profiles, however, the dissolution profiles for the two products may be considered similar without f2 calculation since more than 85% of the drug was dissolved within 15 min (SFDA Guidelines for Bioequivalence, Similarity while G3, with an f2 of (47.5) suggest a lack of similarity between the two dissolution profiles. This study highlights the importance of post-marketing evaluations of generic drug performance.

Optimization of Glibenclamide Loaded Thermoresponsive SNEDDS Using Design of Experiment Approach: Paving the Way to Enhance Pharmaceutical Applicability.

Thermoresponsive self-nanoemulsifying drug delivery systems (T-SNEDDS) offer a promising solution to the limitations of conventional SNEDDS formulations. Liquid SNEDDS are expected to enhance drug solubility; however, they are susceptible to leakage during storage. Even though solid SNEDDS offers a solution to this storage instability, they introduce new challenges, namely increased total dosage and potential for drug trapping within the formulation. The invented T-SNEDDS was used to overcome these limitations and improve the dissolution of glibenclamide (GBC). Solubility and transmittance studies were performed to select a suitable oil and surfactant. Design of Experiments (DoE) software was used to study the impact of propylene glycol and Poloxamer 188 concentrations on measured responses (liquefying temperature, liquefying time, and GBC solubility). The optimized formulation was subjected to an in vitro dissolution study. The optimized T-SNEDDS consisted of Kolliphor EL and Imwitor 308 as surfactants and oil. The optimized propylene glycol and Poloxamer 188 concentrations were 13.7 and 7.9% w/w, respectively. It exhibited a liquefying temperature of 35.0 °C, a liquefying time of 119 s, and a GBC solubility of 5.51 mg/g. In vitro dissolution study showed that optimized T-SNEDDS exhibited 98.8% dissolution efficiency compared with 2.5% for raw drugs. This study presents a promising approach to enhance pharmaceutical applicability by resolving the limitations of traditional SNEDDS.

Formulation of Polyethylene Glycol Based Ibuprofen Nanosuppository Preparations and Assesment of Dissolution

Ibuprofen is widely formulated in oral and rectal dosage forms. Ibuprofen in the rectal route shows c max and t max longer than syrup preparations, this is due to the low solubility of ibuprofen. Nanoparticles are one of the technologies that are widely used to increase the solubility of an active substance. Nanoscale particle size, can increase the solubility of ibuprofen and allow dose reduction. This study aims to formulate ibuprofen nanosuppository preparations, and test the percent dissolution of nanosuppositories compared to conventional suppositories. The ibuprofen nanosuppository formulation consists of ibuprofen lipid component and PEG mix component (PEG 4000: PEG 6000). The ibuprofen lipid component consisted of ibuprofen VCO oil, tween 80 and propylenglycol. This lipid component was then tested for physical characteristics, transmittance, particle size and zeta potential, then the lipid was added to the suppository base component. The responses observed were disintegration time, hardness, and non-intrinsic dissolution efficiency. The test results showed transmittance values of 91.98%, 92.99%, 93.26%. Particle size and potential zeta values of FI = 107, 5 nm, FII 102 nm and FIII 103 nm. The zeta potential were -16.19 mV, -12.44 and -13.25 mV in the lipid component. The test results of the disintegration time of F1, F2, F3 nanosuppositories were 12 minutes, 11 minutes and 10 minutes. The hardness of F1, F2, and F3 were 1.53 kg, 1.43 kg and 1.26 kg and the dissolution efficiency value was higher than conventional suppositories. Modification of ibuprofen nanosuppositories had a significant effect on the percent dissolution of ibuprofen.

Enhancing Albendazole Delivery Using Mesoporous Santa Barbara Amorphous‐15: A Box‐Behnken Design Study

Over 70% of pharmaceutical compounds face the challenge of poor water solubility, which impacts on their bioavailability. This study focuses on the use of Santa Barbara Amorphous‐15 (SBA‐15) mesoporous silica material as carrier, which is synthesized and characterized to address this limitation. Albendazole (ABZ), an antiparasitic agent with low water solubility, serves as model drug. A Box‐Behnken design (BBD) is used to investigate the impact of immersion method loading factors (temperature: 25–50 °C, time: 24–72 h, and SBA‐15 amount: 83.2–252.0 mg) on drug loading percentage (DL%) and dissolution efficiency (DE%). The ABZ loading is confirmed by elemental analysis and Fourier transform infrared spectroscopy. Stability tests are performed, comparing drug dissolution profiles and X‐ray diffraction patterns immediately after loading and after 12 months of storage at 25 °C and 60% relative humidity (RH%). DL% varies between 18% and 36% (w/w), showing that the amount of SBA‐15 is the most significant factor on DL%. The lowest SBA‐15 amount yielded the highest DL%. Regarding DE%, all the design samples exhibit higher values than pure ABZ, with the amount of SBA‐15 being the primary influencing factor. Several samples from the BBD show high DE% (>70%) corresponding to high DL% values. After 12 months, most samples maintain similar dissolution profiles, demonstrating the good stability of the drug in the carrier over time. This study provides valuable insights into optimizing the loading process to enhance ABZ solubility and long‐term stability using mesoporous SBA‐15.

Comprehensive investigation of flue gas component separation and CO2 sequestration in water-saturated porous media of subsurface formation

Flue gas poses subsurface direct storage inefficiency due to its high non-CO2 content, while surface separation, desulfurization and denitrification processes require additional equipment and financial resources. To address these challenges, flue gas subsurface component separation and CO2 sequestration within aquifer were proposed in this paper. CO2 migrates notably slower than N2, leading to the gathering of N2 at gas flooding front and the occurrence of CO2 hysteresis during flue gas filtration within the aquifer. The phenomenon, characterized by gas composition deviations from the original injection mole fractions of N2 and CO2, is referred to as the flue gas component separation. Numerical simulation results indicate that the solubility difference between N2 and CO2 is the primary force driving the separation of components, and the asynchronous filtration velocities of the gas and aqueous phases further promote the separation. Thus, simultaneous N2 separation and CO2 storage can achieve by the optimized gas-water alternate injection, and the efficiencies of N2 separation and CO2 storage are inversely correlated. Increasing N2 mole fraction within the injected flue gas enhances the efficiency of N2 separation, while having a slight effect on CO2 storage. Water vapor in flue gas condenses and integrates into the liquid phase, while O₂ component is produced slightly later than N₂, leading to a marginal reduction in N₂ separation efficiency. The synergistic influences of aquifer temperature and pressure exhibit bidirectionality, stemming from the shift between the dominant factors between CO2 dissolution and gas sweep efficiency. Conditions of relatively lower aquifer temperatures and moderate pressures, particularly in medium permeability aquifers, are more favorable for enhancing N₂ separation and CO₂ storage. This proposal method holds the potential for efficient subsurface separation of flue gas components and concurrent underground storage of CO2, thereby contributing to the reduction of greenhouse gas emissions and mitigation of climate change.

Self-Nanoemulsifying Drug Delivery System Combined with a Polymeric Amorphous System of Glibenclamide for Enhanced Drug Dissolution and Stability.

Self-nanoemulsifying drug delivery systems (SNEDDS) have been widely applied to improve the dissolution and bioavailability of hydrophobic medications like glibenclamide (GB). However, the acid liability of GB limits its loading in SNEDDS formulation owing to the expected drug degradation. The present study investigated the ability of a polymeric amorphous system (PAS) to amorphize raw GB and facilitate its integration within dispersed SNEDDS. Liquid-SNEDDS (L-SNEDDS), solid-SNEDDS (S-SNEDDS), and combined systems (SNEDDS + PAS) were prepared for this purpose. The physicochemical properties of the prepared formulations were examined using a zeta-sizer, SEM, DSC, PXRD, and dissolution apparatus. In addition, GB integrity within formulations following incubation in a stability chamber was also investigated. The prepared formulations were able to be dispersed within the nanosize range. SEM, DSC, and PXRD showed that freeze-drying (FD) was superior to the microwave (MW) method in GB amorphization. Even though L-SNEDDS and S-SNEDDS were able to increase the dissolution efficiency (DE) of GB, drug degradation was observed. However, PAS prepared using FD was able to increase the DE of GB from 2.5% to 84.2% and protect the drug from chemical degradation. The present study revealed that a combined system (SNEDDS + PAS) is a promising approach to enhance the stability of acid-labile drugs and facilitate the integration of amorphous drugs within a dispersed SNEDDS formulation.

Unveiling the dissolution mechanism of calcium ions from CSH substrates in Na2SO4 solution: Effects of Ca/Si ratio

The decalcification behavior of calcium silicate hydrate (CSH) under sulfate attack poses a critical challenge to the long-term durability of cement-based infrastructure, yet understanding its underlying microscopic mechanisms remains elusive. This study employs molecular dynamics to compare the differences in calcium ion dissolution capability of CSH substrates with varying Ca/Si ratios under sulfate solution exposure. The results show that the dissolution amount and dissolution efficiency of Ca are positively correlated with Ca/Si, and the root cause depends on the basic structure of CSH. With the increase of Ca/Si, the electronegativity of CSH decreases, and the adsorption capacity and stability of cations weaken. Meanwhile, Ca ions are less limited by the silicate chain coordination, water molecules are more likely to invade the substrate interior and replace the Ca ions. This research aims to provide a molecular basis for cement production and durability applications in marine engineering.

Fluorescence visualization dynamics of carbonated water injection processes in homogeneous glass micromodels

Understanding the flow behavior of oil–water phases in porous media is crucial for revealing the kinetic mechanisms underlying oil–water movement. In this study, we designed and constructed a fluorescence visualization experimental platform for carbonated water injection (CWI). We evaluated the effects of nine distinct injection rates on oil production and CO2 sequestration capabilities using three types of homogeneous porous structure micromodels. The microscale oil–water seepage behavior at the pore scale was also explored. The experimental results indicate that optimally increasing the injection rate can improve displacement efficiency, whereas excessively high rates may lead to viscous and capillary fingering. The geometry of the micromodels, particularly the hexagonal matrix, demonstrates potential advantages in enhancing oil displacement due to its uniform flow paths. The capillary number (Ca) significantly influences oil droplet capture behavior within micromodels. For instance, micromodel A captures the largest ganglion area at low Ca values, with a noticeable reduction in average ganglion area as Ca increases. Conversely, micromodels B and C exhibit similar trends in ganglion size variation at high Ca values, suggesting a more uniform impact of pore structure on oil droplet capture behavior. At elevated Ca values, capillary forces exert a more uniform and controlled effect on oil droplet capture and release, minimizing size variability. Additionally, the injection rate plays a critical role in CO2 sequestration, with higher rates promoting convective mixing between CO2 and reservoir fluids, thereby enhancing dissolution and storage efficiency. The complexity of the pore structure, characterized by the presence of micropores and macropores, affects the dissolution kinetics and mobility of CO2, influencing sequestration efficiency. These experimental findings provide valuable insights into the dynamics of oil–water motion and the potential for enhanced oil recovery (EOR) and CO2 storage, offering essential guidance for optimizing CWI strategies in the petroleum industry.

Particle Shape-Based Evaluation of the Leaching of Sphalerite Ore in Dilute Acid Solutions

In this study, the effects of changes in particle shapes on dissolution efficiencies in zinc (Zn) recovery from a lead-zinc (Pb-Zn) ore by acid leaching method were investigated. In the experiments with nitric acid (HNO3), sulfuric acid (H2SO4), and hydrochloric acid (HCl), particle size (75-106-150 µm), solids ratio (5-10-15-20-25%), leaching time (30-60-120-180-240 min), acid dosage (0.25-0.5-1-2-5 M) and pulp temperature (30-40-50-60-70 oC) parameters were analyzed. Optimum results were obtained under the conditions of 75 µm particle size, 15% solids ratio, 120 min leaching time, 0.5 M acid dosage, and 50°C pulp temperature for H2SO4; 106 µm particle size, 25% solids ratio, 60 min leaching time, 0.5 M acid dosage, and 70°C pulp temperature for HCl; 75 µm particle size, 20% solids ratio, 60 min leaching time, 1 M acid dosage, and 50°C pulp temperature for HNO3. As a consequence of the tests performed under these optimized conditions, 97.32%, 96.38% and 96.06% Zn dissolution efficiencies were obtained. Within the context of particle shape factor research, microscope images of the leaching residues were obtained from the experiments in which the pulp temperature, acid dosage, and leaching time parameters were examined. The samples obtained from the experiments with all three acids were compared with the ore samples, and the impacts of changes in circularity, roundness, and solidity values on dissolution efficiencies were interpreted.

Comparative Study of Itopride Hydrochloride in-Vitro Drug Release in Various Brands of Sustained Release Capsules By RP-HPLC

Background: The World Health Organisation has advocated the use of generic medicines to make them accessible and affordable but studies have revealed that marketed products do not produce same therapeutic effects and hence are not interchangeable. Dissolution testing of generic solid dosage forms serves as a valuable tool for acquiring dissolution profiles and for assessing the similarity or dissimilarity between the formulations under examination. Objectives: To evaluate the in-vitro drug release profiles of different generic brands of Itopride Sustained release capsules that are commercially available in Indian market and compare them with the innovator product using model dependant and as well as model independent methods. To determine whether same medicine manufactured by different brands are interchangeable. Materials & Methods: In this study Eight generic brands of Itopride 150mg sustained release capsules available in the Indian market were evaluated using dissolution test with the aim to assess their bioequivalence with the innovator product (Ganaton OD). Dissolution studies were performed using USP type II apparatus at 100 rpm in 900 ml 0.1N HCl while maintaining a temperature of 37±0.5 ºC. The samples were estimated by a validated HPLC method. Dissolution test results were statistically evaluated by employing both model dependant and model independent methods. In model dependant experimental data obtained for each dissolution profile were transformed by applying the equations of different kinetic models and the best-fit model was selected whereas in model independent approach fit factors, dissolution efficiency and mean dissolution times were calculated. Results: The Weibull model best explained the release of drugs from all the brands. Upon statistical evaluation of dissolution test results its was found that while similarity factor f2 was within the limits for all generic brands, difference factor f1 of two brands was out of acceptable range thus questioning their bioequivalency with the innovator product. Also the dissolution efficiency of four out of the brands was out of acceptable limits. Keywords: bioequivalence, difference factor (f1), similarity factor (f2), dissolution profile, comparison and evaluation..

The Milling Method in Formation of Inclusion Complex p-Methoxycinnamic Acid-Hydroxypropyl-β-Cyclodextrin.

p-methoxycinnamic acid (pMCA) is a substance with several pharmacological activities, derived from the rhizome of Kaempferia galanga Linn. The solubility of pMCA can be increased by the formation of inclusion complexes (IC) using hydroxypropyl-βcyclodextrin (HPβCD) compounds. IC are obtained through the milling method, which is a simple, environmentally friendly, and low-cost manufacturing method. The process involves the pounding of material with a certain speed and impact force. This research aims to characterize the pMCA-HPβCD IC made using the milling method. Milling the mixture of pMCA and HPβCD using a ball mill is a common technique to enhance the formation of the inclusion complex. The IC’s physical characteristics were analyzed in terms of their morphology, particle size, crystallinity, and thermal properties. The dissolution profile was also performed using paddle-typed dissolution apparatus (Type II) with 500 mL distilled water as dissolution medium. The amount of pMCA dissolved was determined using UV spectrophotometry. The dissolution parameter was determined as dissolution efficiency at 60 minutes (DE60). The IC particles were irregular in shapes and porous. The size was reduced as compared to the individual components. The XRD revealed that the ICs were amorphous. The DE60 of IC increased by a factor of 4.3 compared to the pure pMCA. In conclusion, the milling method successfully formed complex of pMCA-HPβCD with different characteristics from the initial compound and was significantly increased the percentage of the dissolved pMCA.

Exploring Co-Amorphous Formulations Of Nevirapine: Insights From Computational, Thermal, And Solubility Analyses.

This study aimed to assess the formation of nevirapine (NVP) co-amorphs systems (CAM) with different co-formers (lamivudine-3TC, citric acid-CAc, and urea) through combined screening techniques as computational and thermal studies, solubility studies; in addition to develop and characterize suitable NVP-CAM. NVP-CAM were obtained using the quench-cooling method, and characterized by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and polarized light microscopy (PLM), in addition to in vitro dissolution in pH 6.8. The screening results indicated intermolecular interactions occurring between NVP and 3TC; NVP and CAc, where shifts in the melting temperature of NVP were verified. The presence of CAc impacted the NVP equilibrium solubility, due to hydrogen bonds. DSC thermograms evidenced the reduction and shifting of the endothermic peaks of NVP in the presence of its co-formers, suggesting partial miscibility of the compounds. Amorphization was proven by XRD and PLM assays. In vitro dissolution study exhibited a significant increase in solubility and dissolution efficiency of NVP-CAM compared to free NVP. Combined use of screening studies was useful for the development of stable and amorphous NVP-CAM, with increased NVP solubility, making CAM promising systems for combined antiretroviral therapy.

Co‐Based Metal–Organic Frameworks With Dual Redox Active Centers for Lithium‐Ion Batteries With High Capacity and Excellent Rate Capability

AbstractSmall molecule organic materials are widely used as anode materials for lithium‐ion batteries (LIBs) due to their high reversible capacity, designable structure, and environmental friendliness. However, they suffer from poor intrinsic electronic conductivity, severe dissolution, and low initial coulombic efficiency. Recently, metal–organic frameworks (MOFs) have demonstrated in metal‐ion batteries, outperforming some small molecule organic materials in terms of both cycling stability and rate capability. Herein, the first rational design and synthesis of a new cobalt‐based MOF (CoBPDCA), are reported employing cobalt(II) nitrate as the metal source and small organic molecules (2,2‐bipyridyl‐4,4‐dicarboxylic acid, BPDCA) as the ligands, which shows exceptional chemical stability and impressive electron conductivity. Most importantly, CoBPDCA electrodes deliver a high reversible capacity of 1112.9 mAh g−1 at 0.05 C (1 C = 1000 mA g−1) and outstanding high‐rate durability (166.3 mAh g−1 after 2500 cycles at 10 C). Employing a series of spectroscopic and morphological characterizations and density functional theory (DFT) calculations, it is revealed that these impressively electrochemical performances are contributed to the dual active redox centers of Co cations and BPDCA ligands (CN and CO groups), and the superb electron conductivity. This work might provide a new strategy and a deeper understanding of the other MOFs' development for LIBs.

Formulation and optimization of olanzapine-carboxylic acid cocrystals orodispersible tablets: In-vitro/ In-vivo study

Oromucosal delivery of olanzapine (OLZ) is an optimal strategy to overcome low oral bioavailability as well as improve medication adherence. However, its poor aqueous solubility may hinder its absorption through the buccal mucosa. The aim of the study is to enhance OLZ solubility and dissolution via cocrystal formation, followed by incorporation into an orodispersible tablet (ODT) based on an effervescent mixture and crospovidone as a superdisintegrant mixture. OLZ was cocrystallized with different carboxylic acids using slow solvent evaporation, and the optimal cocrystal formula was subjected to solid state characterization. Central composite design (CCD) was used in the modeling and optimization of the ODT independent variables (amounts of crospovidone and effervescent mixture). The optimized OLZ cocrystal ODTs were subjected to microenvironmental pH, stability, and in-vivo studies. The results revealed that the OLZ:itaconic acid at 1:1 M ratio showed a 7.86 fold increase in OLZ solubility and 86.71 ± 1.07 % dissolution efficiency (DE60 %) with FTIR, XRPD, and DSC diffractograms that confirmed the cocrystal formation. The optimized OLZ cocrystal ODTs exhibited hardness of 3.6 ± 0.1 kg/cm2, disintegration time of 11.66 ± 1.52 s, wetting time of 36.33 ± 2.51 s, and 94.26 ± 2.77 % OLZ released within 15 min with a DE60 % of 91.65 ± 0.98 %. Finally, the optimized OLZ cocrystal ODTs showed a significant (p < 0.01) higher Cmax and AUC with a relative bioavailability of 139.08 % compared to the Schisolazine©10 mg ODTs. These results suggest that OLZ:itaconic acid cocrystal incorporated into an ODT containing a superdisintegrant mixture of effervescence mixture and crospovidone is a potential approach for enhancement of oromucosal delivery of OLZ.

Seafloor alkalinity enhancement as a carbon dioxide removal strategy in the Baltic Sea

Carbon dioxide removal from the atmosphere and storage over long times scales in terrestrial and marine reservoirs is urgently needed to limit global warming and for sustainable management of the global carbon cycle. Ocean alkalinity enhancement by the artificial addition of carbonate minerals to the seafloor has been proposed as a method to sequester atmospheric CO2 and store it in the ocean as dissolved bicarbonate. Here, a reaction-transport model is used to scrutinize the efficacy of calcite addition and dissolution at a well-studied site in the southwestern Baltic Sea – a brackish coastal water body in northern Europe. We find that most calcite is simply buried without dissolution under moderate addition rates. Applying the model to other sites in the Baltic Sea suggests that dissolution rates and efficiencies are higher in areas with low salinity and undersaturated bottom waters. A simple box model predicts a tentative net CO2 uptake rate from the atmosphere of 3.2 megatonnes of carbon dioxide per year for the wider Baltic Sea after continually adding calcite to muddy sediments for 10 years. More robust estimates now require validation by field studies.

New Mn Electrochemistry for Rechargeable Aqueous Batteries: Promising Directions Based on Preliminary Results

Aqueous batteries with metal anodes exhibit robust anodic capacities, but their energy densities are low because of the limited potential stabilities of aqueous electrolyte solutions. Current metal options, such as Zn and Al, pose a dilemma: Zn lacks a sufficiently low redox potential, whereas Al tends to be strongly oxidized in aqueous environments. Our investigation introduces a novel rechargeable aqueous battery system based on Mn as the anode. We examine the effects of anions, electrolyte concentration, and diverse cathode chemistries. Notably, the ClO4‐based electrolyte solution exhibits improved deposition and dissolution efficiencies. Although stainless steel (SS 316 L) and Ni are stable current collectors for cathodes, they display limitations as anodes. However, using Ti as the anode resulted in increased Mn deposition and dissolution efficiencies. Moreover, we evaluate this system using various cathode materials, including Mn‐intercalation‐based inorganic (Ag0.33V2O5) and organic (perylenetetracarboxylic dianhydride) cathodes and an anion‐intercalation‐chemistry (coronene)‐based cathode. These configurations yield markedly higher output potentials compared to those of Zn metal batteries, highlighting the potential for an augmented energy density when using an Mn anode. This study outlines a systematic approach for use in optimizing metal anodes in Mn metal batteries, unlocking novel prospects for Mn‐based batteries with diverse cathode chemistries.

Selective Leaching and Separation of Uranium from Ochre-Umm Greifat, Red Sea Coast, Central Eastern Desert, Egypt

The Ochre-Umm Greifat area is one of the Red Sea areas with high concentrations of iron and zinc, which is formed from hydrothermal solutions as a result of the structural activity that occurred in the Red Sea Zone during the Pleistocene period. These deposits are also accompanied by deposits of low- to high uranium grade. In addition to Zn, Pb, and Cu anomalies, particularly in fault zones and their branches affecting the study area, although there are numerous zinc minerals in the Ocher-Greifat area, uranium minerals are scarce, with only one mineral, compreignacite, being recorded and the majority of the uranium being present as an adsorbed element on iron and/or clay stones. In addition, uranothorite is extremely rare and occurs as fine grains embedded in rocks. A technological sample was taken from an iron-rich clay area in a fault zone and was found to assay 700-ppm uranium. The leachability of uranium from the used sample was investigated using an alkaline solution based on the chemical and mineralogical composition of the used sample. The selected ore is treated with Na2CO3 and NaHCO3 in the presence of H2O2 as oxidant. Many digestion factors are studied and optimized. Under the optimum leaching conditions, the uranium dissolution efficiency is around 84%. For the uranium separation, the pH of the leach liquor is adjusted at 10, then subjected to a solvent extraction step using 4% Aliquat®336/kerosene in the presence of isodecanol as third-phase prevention. The loaded organic solvent was then treated with NaOH/H2O2 solution as a stripping solution. Finally, the resultant solution is subjected to a precipitation step using ammonia solution.

ISOLASI DAN UJI AKTIVITAS BAKTERI PELARUT FOSFAT DARI RHIZOSFER TANAMAN PADI (Oryza sativa L.) PADA FASE VEGETATIF DAN GENERATIF

Phosphorus (P) is a very important macronutrient for plant growth and development. Plants cannot fully absorb phosphate in the soil, only 25% can be absorbed by plants while Al binds 75% in the soil. Plants absorb P from the soil in the form of phosphate ions, especially in the form of H2PO4- and HPO42- which are present in soil solutions. H2PO4 ion is more common in acidic soils, while higher pH (&gt; 7) forms HPO42- is more dominant. The lack of P dissolved in the soil causes the plant to get P intake from other sources such as fertilizers. Efforts to increase the efficiency of Phosphate dissolution, currently the use of Phosphate solubilizing microbes have begun to be developed. This study aims to determine the number of isolated bacterial colonies, the ability of phosphate-solubilizing bacteria, and the levels of P-available before and after giving phosphate-solubilizing bacterial isolates. This research was conducted at the Laboratory of Plant Pests and Diseases and in the Laboratory of Soil and Environmental Conservation, Faculty of Agriculture, Universitas Muslim Indonesian, Makassar, Indonesia, from November to December 2020. The materials used in this study were HVS paper, aluminum foil, plastic wrap, labels, rubber, Pikovskaya media, sterile distilled water, plastic, cotton, tissue, 70% alcohol, rubbing alcohol, NA (Natrium Agar) media, soil samples from the vegetative and generative phases of rice rhizosphere from Tebba Village, Salomekko District, Bone Regency. This research method is a qualitative exploratory research based on data analysis. The results of this study indicated that the vegetative phase 3 rice isolates with 10-5 dilution had the highest number of colonies, namely 9,200,000 CFU /ml. Plant generative phase 3 rice isolate at 10-5 dilution had the highest average phosphate solubility with an IPF value of 5.56. Plant generative phase 3 rice isolate had the highest average P-available before and after the addition of Phosphate Solubilizing Bacteria isolates, namely 3.83 ppm, and after the addition of Phosphate Solubilizing Bacteria isolates increased to 9.58 ppm.