Removal Of Calcium Research Articles

Nano-zerovalent copper biochar composite for treating selenium oxyanions in water: synthesis, evaluation, removal mechanism, density functional theory, and molecular dynamics simulations

This study focused on the synthesis and applicability of nano-zerovalent copper biochar composite (nCu0-BC) for treating selenium oxyanions in water. In batch experiments, 2 g/L of nCu0-BC efficiently removed 98.96 % of selenite [Se(IV)] and 98.78 % of selenate [Se(VI)] in 10 mL of water (10 mg/L for each Se oxyanion) in 12 h. Both Se(IV) and Se(VI) removal followed the pseudo-second-order kinetic model, and their removal rates increased by 3.02 and 7.44-folds, respectively, by increasing the nCu0-BC dose from 2 to 3 g/L. Co-existing ions had minimal effect on Se(VI) removal except PO43- which significantly reduced the Se(VI) removal; while the presence of calcium, sodium, nitrate, and bicarbonate lowered Se(IV) removal by 7–10 %. Spectroscopic analyses were employed to characterize virgin and spent nCu0-BC. XRD analysis revealed that nCu0-BC contains copper in two crystalline phases, i.e., zerovalent copper (Cu0) and cuprous oxide. XPS analysis showed that Cu0 was the main source of electrons for the reduction of Se oxyanions; Se(IV) was reduced to Se(0) while Se(VI) was reduced to Se(IV) and Se(0). The density functional theory simulation indicated that both Se(VI) and Se(IV) form stable complexes with nCu0-BC with the calculated adsorption energies of −3,657 kcal/mol and −3,669 kcal/mol, respectively. The molecular dynamic simulation revealed a high adsorption affinity of Se oxyanions towards nCu0-BC owing to the presence of Cu0 on its surface, resulting in stable bidentate binuclear complexes formation between Se oxyanions and Cu0.

Virtual calcium removal in calcified coronary arteries with photon-counting detector CT-first in-vivo experience.

To evaluate the feasibility and accuracy of quantification of calcified coronary stenoses using virtual non-calcium (VNCa) images in coronary CT angiography (CCTA) with photon-counting detector (PCD) CT compared with quantitative coronary angiography (QCA). This retrospective, institutional-review board approved study included consecutive patients with calcified coronary artery plaques undergoing CCTA with PCD-CT and invasive coronary angiography between July and December 2022. Virtual monoenergetic images (VMI) and VNCa images were reconstructed. Diameter stenoses were quantified on VMI and VNCa images by two readers. 3D-QCA served as the standard of reference. Measurements were compared using Bland-Altman analyses, Wilcoxon tests, and intraclass correlation coefficients (ICC). Thirty patients [mean age, 64 years ± 8 (standard deviation); 26 men] with 81 coronary stenoses from calcified plaques were included. Ten of the 81 stenoses (12%) had to be excluded because of erroneous plaque subtraction on VNCa images. Median diameter stenosis determined on 3D-QCA was 22% (interquartile range, 11%-35%; total range, 4%-88%). As compared with 3D-QCA, VMI overestimated diameter stenoses (mean differences -10%, p < .001, ICC: .87 and -7%, p < .001, ICC: .84 for reader 1 and 2, respectively), whereas VNCa images showed similar diameter stenoses (mean differences 0%, p = .68, ICC: .94 and 1%, p = .07, ICC: .93 for reader 1 and 2, respectively). First experience in mainly minimal to moderate stenoses suggests that virtual calcium removal in CCTA with PCD-CT, when feasible, has the potential to improve the quantification of calcified stenoses.

Modeling and optimization of atmospheric CO2 capture for neutralization of high alkaline wastewaters using response surface methodology

Lab-scale stirrer bubble and lab-scale stepped continuous flow capillary columns were developed to neutralize lime precipitation treated slaughterhouse wastewater (SWW) and recover the volatilized ammonia, using atmospheric CO2. These experiments were carried out using central composite design based on the response surface methodology. The carbonation process occurred in both processes. For the bubbling process, numerical optimization indicated a final pH of 8 with calcium and ammonium nitrogen removals of 76.0 and 66.2%, respectively, applying 21 h, air flow rate at 65 L h−1, the stirring speed at 52 rpm, and SWW volume at 178 mL. It was also observed that increasing the air flow rate can avoid the stirring step. For the capillary process, a pH of 8.2 and calcium and ammonium nitrogen removals of 81.0 and 57.5% were achieved, applying a SWW flow rate at 1.2 mL min−1, air flow rate at 90 L h−1, and capillary area at 700 cm2. Under optimal conditions, the flow capillary column was able to neutralize different SWW volumes, 178–478 mL, without significant differences in the collected samples, with the operation time varying between 4.48 and 10.20 h, respectively.

Determination of 93Zr, 237Np and Th radionuclides in radioactive waste and mineral samples: extension of the method for determination of actinides

A novel method has been developed for the simultaneous determination of difficult-to-measure (DTM) nuclides 93Zr, 237Np, 232Th, 230Th and 228Th using a DGA resin® (containing N,N,N′,N′-tetra-n-octyl-diglycolamide) column for simultaneous separation of Zr and actinides followed by purification of Zr, Np and Th on a TEVA resin® (containing Aliquat 336) column. Samples are destroyed by fusion with sodium hydroxide or by acid destruction using HNO3, HCl and HF. Pre-concentration procedure tailored to the extraction chromatography is based on co-precipitation of Zr and actinides and removal of alumina, silica, iron and calcium. The concentrations of 93Zr, 237Np and Th nuclides are determined by ICP-MS and α spectrometry, respectively. High chemical recoveries (≥ 73%) and separation factors were obtained for Zr, Np and Th both in evaporation concentrates of an NPP and various samples of mineral origin such as soil and concrete. The procedure can be easily combined with the simultaneous separation of other actinides (Pu, Am, U) using the same DGA column that has been described in our previous papers (Cassette et al. in Appl Radiat Isot 68:122–130, 2010 and Groska et al. in J Radioanal Nucl Chem 309(3):1145–1158, 2016).

Kinetic analysis and mechanism of nitrate, calcium, and cadmium removal using the newly isolated Pseudomonas sp. LYF26

The co-existence of heavy metals and nitrate (NO3−-N) pollutants in wastewater has been a persistent global concern for a long time. A strain LYF26, which can remove NO3−-N, calcium (Ca(II)), and cadmium (Cd(II)) simultaneously, was isolated to explore the properties and mechanisms of synergistic contaminants removal. Different conditions (Cd(II) and Ca(II) concentrations and pH) were optimized by Zero-, Half-, and First-order kinetic analyses to explore the environmental parameters for the optimal effect of strain LYF26. Results of the kinetic analyses revealed that the optimal culture conditions for strain LYF26 were pH of 6.5, Cd(II) and Ca(II) concentrations of 3.00 and 180.00 mg L−1, accompanied by Ca(II), Cd(II), and NO3−-N efficiencies of 53.10%, 90.03%, and 91.45%, respectively. The removal mechanisms of Cd(II) using strain LYF26 as a nucleation template were identified as biomineralization, lattice substitution, and co-precipitation. The differences and changes of dissolved organic matter during metabolism were analyzed and the results demonstrated that besides the involvement of extracellular polymeric substances in the precipitation of Cd(II) and Ca(II), the high content of humic acid-like species revealed a remarkable contribution to the denitrification process. This study is hopeful to contribute a theory for further developing microbially induced calcium precipitation used to treat complex polluted wastewater.

Mechanisms of ammonia, calcium and heavy metal removal from nutrient-poor water by Acinetobacter calcoaceticus strain HM12

An Acinetobacter calcoaceticus strain HM12 capable of heterotrophic nitrification-aerobic denitrification (HN-AD) under nutrient-poor conditions was isolated, with an ammonia nitrogen (NH4+-N) removal efficiency of 98.53%. It can also remove heavy metals by microbial induced calcium precipitation (MICP) with a Ca2+ removal efficiency of 75.91%. Optimal conditions for HN-AD and mineralization of the strain were determined by kinetic analysis (pH = 7, C/N = 2.0, Ca2+ = 70.0 mg L−1, NH4+-N = 5.0 mg L−1). Growth curves and nitrogen balance elucidated nitrogen degradation pathways capable of converting NH4+-N to gaseous nitrogen. The analysis of the bioprecipitation showed that Zn2+ and Cd2+ were removed by the MICP process through co-precipitation and adsorption (maximum removal efficiencies of 93.39% and 80.70%, respectively), mainly ZnCO3, CdCO3, ZnHPO4, Zn3(PO4)2 and Cd3(PO4)2. Strain HM12 produces humic and fulvic acids to counteract the toxicity of pollutants, as well as aromatic proteins to increase extracellular polymers (EPS) and promote the biomineralization process. This study provides a experimental evidence for the simultaneous removal of multiple pollutants from nutrient-poor waters.

Removal of calcium from water by zeolites with gravity-driven membrane filtration for water treatment without electricity

Calcium removal from water can be accomplished by zeolite adsorption combined with gravity-driven membrane filtration. Zeolite size and Si/Al ratio significantly affect calcium removal and membrane filterability.

Simultaneous removal of calcium, cadmium and tetracycline from reverse osmosis wastewater by sycamore deciduous biochar, shell powder and polyurethane sponge combined with biofilm reactor

The treatment of reverse osmosis concentrate generated from urban industrial sewage for resource recovery has been hot. In this research, a biofilm reactor was constructed by combining sycamore deciduous biochar, shell powder, and polyurethane sponge loaded with Zobellella denitrificans sp. LX16. For ammonia nitrogen (NH4+-N), calcium (Ca2+), chemical oxygen demand (COD), cadmium (Cd2+), and tetracycline (TC), the removal efficiencies were 98.69 %, 83.95 %, 97.26 %, 98.34 %, and 69.12 % at a hydraulic retention time (HRT) of 4 h, pH of 7.0, and influent salinity, Ca2+, and TC concentrations of 1.0, 180.0, and 3.0 mg/L, respectively. The biofilm reactor packing has a three-dimensional structure to ensure good loading of microorganisms while promoting electron transfer and metabolic activity of microorganisms and increasing the pollutant tolerance and removal efficiency. The reactor provides a practical reference for the sedimentation of reverse osmosis concentrate to remove Cd2+ and TC by microbial induced calcium precipitation (MICP).

PROCESSES OF FORMATION OF SODIUM BICARBONATE GROUNDWATER IN THE RAINWATER – SANDSTONE SYSTEM

In modeling, a study was made of the processes of the physical-chemical interaction between rainwater and sandstone. It was stated that as a result of the interaction, already in mineralization of water equal to 55 mg/l, there emerges a pure soda solution whose sharp oxidation properties, retaining up to 200 mg/l, change to sharp restorative when exceeding this value. At the mineralization of water equal to 30 mg/l, an intensive increase in the number of hydroxide ions in a solution makes it highly alkaline. The active removal of calcium from solution is due to the formation of not only solid phase calcite, whose share does not exceed 15 %, but largely limonite, whose content is as high as 25 %. The accumulation of high concentrations of sodium in a solution is caused by the absence of its secondary mineral formations in a wide range of the rock/water ratios. Under reservoir conditions, the solution is composed of carbonate. This solution, transferred from reservoir to surface conditions, undergoes transformation in the result of interaction with the atmosphere. A decrease in pH of the solution resulted in the acquisition of sharp oxidation properties, with the cation, sulfate, fluorine and chlorine contents remained at the level corresponding to the reservoir conditions and the cardinal changes affected the carbonate system components and silicon compounds. Hydrosilicate ion was transformed into precipitated silicon oxide. Carbonate ions were transformed into hydrocarbonate, and the additional hydrocarbonate ions were formed for the solution to preserve a state of equilibrium after the removal of the representative number of hydrosilicate ions therefrom. An amount of carbon required for their formation was extracted from the atmosphere. The solution became hydrocarbonate, with hydrosilicate ions almost disappeared therefrom. Different calculation options for model solution, which is in equilibrium with the atmosphere, correlate with the representative group of soda-type groundwater. The calculation results are confirmed by field observations over the authigenic mineral formation on a large part of the Russian territory.

Enhanced osteogenicity of the demineralized bone-dermal matrix composite by the optimal partial demineralization for sustained release of bioactive molecules.

Allogenic demineralized bone matrix (DBM), processed to expose bioactive proteins imbedded by calcium salts, is widely used for bone repair and regeneration as an alternative to the autologous bone graft. However, demineralized bone matrices from tissue banks vary significantly in residual calcium content and osteogenicity for clinical bone regeneration. The present study produced DBM with various residual calcium contents by partial demineralization using ethylenediaminetetraacetic acid disodium (EDTA) and hydrochloric acid. Compositional analysis reveals that, as the percent weight loss of bone materials increases from 0% to 74.9% during demineralization, the residual calcium content of DBM decreases from 24.8% to 0.2% and collagen content increases from 29.7% to 92.6%. Calorimetrical analysis and Fourier transform infrared (FTIR) analysis demonstrated that demineralization to the residual calcium content of <4% enables the complete exposure and/or release of bone collagen fibers and other bioactive molecules. In order to evaluate the relationship between the extent of demineralization and the osteogenicity of DBM, DBM particles were fabricated with the aid of acellular dermal matrix (ADM) microfibers to form flexible foam-like DBM/ADM composites. Proteomic analysis identified various type collagens and bone formation-related bioactive molecules in both ADM and DBM. Using the rat bilateral Φ = 5 mm calvarium defect repair model, the study had shown that the DBM/ADM composite with ~20% DBM residual calcium (e.g., ~40% calcium being removed) maximized the osteogenicity for bone defect repair after 4 and 8 weeks. DBM with ~40% calcium removal had the maximal osteogenicity presumably through the sustained release of bioactive molecules during the process of bone regeneration.

Vitamin K and Calcium Chelation in Vascular Health.

The observation that the extent of artery calcification correlates with the degree of atherosclerosis was the background for the alternative treatment of cardiovascular disease with chelator ethylenediamine tetraacetate (EDTA). Recent studies have indicated that such chelation treatment has only marginal impact on the course of vascular disease. In contrast, endogenous calcium chelation with removal of calcium from the cardiovascular system paralleled by improved bone mineralization exerted, i.e., by matrix Gla protein (MGP) and osteocalcin, appears to significantly delay the development of cardiovascular diseases. After post-translational vitamin-K-dependent carboxylation of glutamic acid residues, MGP and other vitamin-K-dependent proteins (VKDPs) can chelate calcium through vicinal carboxyl groups. Dietary vitamin K is mainly provided in the form of phylloquinone from green leafy vegetables and as menaquinones from fermented foods. Here, we provide a review of clinical studies, addressing the role of vitamin K in cardiovascular diseases, and an overview of vitamin K kinetics and biological actions, including vitamin-K-dependent carboxylation and calcium chelation, as compared with the action of the exogenous (therapeutic) chelator EDTA. Consumption of vitamin-K-rich foods and/or use of vitamin K supplements appear to be a better preventive strategy than EDTA chelation for maintaining vascular health.

A kinetic and thermodynamic study of the removal of calcium and magnesium from aqueous solutions similar to those of complex sulphide flotation by the addition of sodium carbonate

ABSTRACT The use of recycled water in flotation has a negative impact on flotation of sulphide mineral species because these waters contain chemical species that affect the recovery and selectivity of the process. This study aims to study the reaction mechanism between aqueous calcium and magnesium sulphate contained in the water released by complex sulphide flotation process, and the carbonate ions added to the water as sodium carbonate (Na2CO3). The addition of Na2CO3 has been shown to have a positive effect on the recovery and grade of the final Pb-Cu concentrate obtained, but the reasons of this are not yet fully understood. The present study was conducted by adding Na2CO3 to a saturated gypsum solution containing Mg(II). Analytical techniques such as XRD, TGA and zeta potential measurements were used to characterise the obtained solids. It was observed that the addition of Na2CO3 favoured the precipitation of the Ca(II) as calcite and vaterite. The reaction kinetics was found to be of second-order. In the case of magnesium alone, the precipitates are amorphous. This study provides new information on the reaction mechanism between metal ions and carbonates. The information collected can help design processes for the removal of ions from flotation water.

Interaction of Ca2+ and Fe3+ in co-precipitation process induced by Virgibacillus dokdonensis and its application

Biomineralization has garnered significant attention in the field of wastewater treatment due to its notable cost reduction compared to conventional methods. The reinjection water from oilfields containing an exceedingly high concentration of calcium and ferric ions will pose a major hazard in production. However, the utilization of biomineralization for precipitating these ions has been scarcely investigated due to limited tolerance among halophiles towards such extreme conditions. In this study, free and immobilized halophiles Virgibacillus dokdonensis were used to precipitate these ions and the effects were compared, at the same time, biomineralization mechanisms and mineral characteristics were further explored. The results show that bacterial concentration and carbonic anhydrase activity were higher when additionally adding ferric ion based on calcium ion; the content of protein, polysaccharides, deoxyribonucleic acid and humic substances in the extracellular polymers also increased compared to control. Calcium ions were biomineralized into calcite and vaterite with multiple morphology. Due to iron doping, the crystallinity and thermal stability of calcium carbonate decreased, the content of OC = O, NC = O and CO-PO3 increased, the stable carbon isotope values became much more negative, and β-sheet in minerals disappeared. Higher calcium concentrations facilitated ferric ion precipitation, while ferric ions hindered calcium precipitation. The immobilized bacteria performed better in ferric ion removal, with a precipitation ratio exceeding 90%. Free bacteria performed better in calcium removal, and the precipitation ratio reached a maximum of 56%. This research maybe provides some reference for the co-removal of calcium and ferric ions from the oilfield wastewater.

Artificial intelligence models for predicting calcium and magnesium removal by polyfunctional ketone using ensemble machine learners

Calcium (Ca2+) and magnesium (Mg2+) are the major scaling ions of reverse osmosis concentrate in zero-liquid discharge systems, causing performance decline. In this study, we predicted the removal of Ca2+ and Mg2+ from simulated reverse osmosis concentrate by functional polyketones (FPKs). Four amines, including 1,2-diaminopropane (DAP), 1-(2-aminoethyl) piperazine (AEP), 1-(3-aminopropyl) imidazole (API), and butyl amine (BA) used to synthesize FPKs. The effects of various factors such as the amount of adsorbent, feed water concentration, and pH were investigated for process optimization. In this study, ensemble learner artificial intelligence models, decision tree (DT), extreme gradient boost (XGB), and random forest (RF) were used to predict Ca2+ and Mg2+ removal by the FPKs. Datasets were collected experimentally using FPKs to remove Ca2+ and Mg2+ from the simulated reverse osmosis concentrate. The predictions were made by XGB, DT, and RF models for the first chosen amine for Ca2+ and then for Mg2+, subsequently, this process was repeated with each amine. The developed DT, RF, and XGB models demonstrated higher coefficients of determination for predicting Mg2+ removal by AEP and DAP (R2 = 0.841–0.935) than by API and BA (R2 = 0.774–0.801) except in the RF and XGB model results (R2 = 0.801–0.846). Overall, the XGB model displayed good results for both Ca2+ and Mg2+ removal but slight changes were observed in the AEP and BA predictions by DT and RF. Therefore, artificial intelligence models may be a viable alternative for further insight in predicting Ca2+ and Mg2+ removal by FPKs from simulated reverse osmosis concentrate.

On the origin of F-wave: involvement of central synaptic mechanisms.

Neurophysiological methods are used widely to gain information about motor neuron excitability and axon conduction in neurodegenerative diseases. The F-wave is a common biomarker used to test motor neuron properties in the diagnosis of neurological diseases. Although the origin of the F-wave is a subject of debate, the most widely accepted mechanism posits that the F-wave is generated by the backfiring of motor neurons stimulated antidromically from the periphery. In this study, we developed an ex vivo mouse sciatic nerve-attached spinal cord preparation with sensory axons severed. In this preparation, stimulation of the whole sciatic nerve or its tibial branch evoked responses with the electrophysiological signatures of F-waves. Manipulations of synaptic transmission by either removal of extracellular calcium or block of post-synaptic glutamate receptors abolished these responses. These results suggest that F-waves are mediated by spinal microcircuits activated by recurrent motor axon collaterals via glutamatergic synapses.

Floating Constructed Wetlands Efficiency in Removal of Total Hardness, Calcium and Magnesium from Secondary Treated Sewage Water

Floating Constructed wetlands (FCWs) also popular as Floating Treatment Wetlands (FTWs) were used in situ for suspended solids,heavy metals, biological oxygen demand (BOD), chemical oxygen demand (COD), faecal coliform bacteria, nutrients and heavy metalsremediation from various types of wastewater. However, there was limited data available on total hardness (TH), calcium (Ca2+) andmagnesium (Mg2+) ions removal from secondary treated sewage water (STSW). This article focuses on TH, Ca2+ and Mg2+ ions removalefficiency of FCWs from STSW. Mesocosms include a control (without FCWs), FCWs planted with macrophyte plant species Cannaindica var. indica L. (S1) and Typha angustifolia L. (S2) and one mixed culture with both Typha and Canna plants (S3). The changes in TH,Ca2+ and Mg2+ concentration in wastewater were recorded at a 7-day hydraulic retention time (HRT) for 7 batches. Mean percentageremoval efficiency recorded was 9.8, 1.7, 4.9 and 11.2% for TH, -3.4, 7.6, 27.1 and 14.1% for Ca2+and 29.5, 4.2, -0.6, and -0.6% for Mg2+,in Control, S1, S2, S3 FCWs respectively. Results showed that S2 and S3 FCWs are effective in TH and Ca2+ removal but not for Mg2+ ions.Thus, FCWs can reduce TH and Ca2+ ions concentration along with nutrients from STSW.

Sodium benzyl sulfonate functionalized-bentonite as a novel adsorbent for water softening process

In this work, novel Sodium benzyl sulfonate functionalized-bentonite (SBSB) adsorbent was synthesized through the reaction of bentonite with benzyl alcohol and chlorosulfonic acid. The prepared adsorbent was characterized using Low-angle XRD, FT-IR and TGA methods, and applied for the removal of calcium and magnesium ions from water solutions. The effect of contact time and initial hardness concentration on the hardness removal efficiency of the prepared adsorbents were studied. It was found that the adsorption was reached the equilibrium condition within about 60 min, and the maximum adsorption capacity (52.5 mg g−1) was achieved in the hardness of 150 mg L−1. Compared to pristine bentonite, the adsorption efficiency of SBSB was significantly enhanced, which is ascribed to the presence of benzyl sulfonate functional groups on its surface. The adsorption isotherm of calcium and magnesium ions on SBSB was described by Langmuir and its adsorption kinetic behavior followed pseudo-second-order model.

The effect of calcium removal from skim milk by ion exchange on the properties of the ultrafiltration retentate

New processes are needed to produce concentrated milk feedstocks with tailored calcium content, due to the direct link between calcium concentration and final product texture and functionality. Skim milk treatment with cation exchange resin 1% (w/v) or 2% (w/v) prior to ultrafiltration to a volumetric concentration factor (VCF) of 2.5 or 5 successfully decreased the calcium concentration by 20–30% and produced concentrates with solids content at ∼22–24 g 100 g−1 at a VCF of 5. Calcium reduction partially solubilized the casein micelles, increasing the concentration of soluble protein and individual caseins, leading to decreased turbidity but increased protein hydration and hydrophobicity. Decalcification (2% (w/v) resin treatment) reduced thermal stability, significantly decreasing the denaturation temperature of α-lactalbumin and β-lactoglobulin in the milk by ∼3 °C and ∼1 °C respectively. Filtration was also altered, reducing permeation flux and the gel concentration and increased filtration time. When combined, calcium reduction and filtration altered functional properties including soluble calcium, soluble protein and sedimentable solids, with increased milk protein hydration also contributing to increased viscosity. This study provides a route to produce calcium-reduced milk concentrates with potential for use in retentate-based dairy products with tailored functionality.

Facile preparation of bentonite/nano-gamma alumina composite as a cost-effective adsorbent for Ca2+ removal from aqueous solutions

Desalination and removing elements such as calcium from aqueous solutions is very important to improve water quality. In this study, bentonite/nano γ-alumina composites were utilized as a low-cost adsorbent for calcium removal from aqueous solutions. To investigate the adsorption process, several experiments were conducted, including initial calcium concentration, adsorbent dosage, pH, contact time, and the γ-alumina content in the composite. Increasing γ-alumina amounts in the composite by more than 1% had the reverse effect due to agglomeration. The increase in specific surface area for bentonite-1wt% γ-alumina compared to bentonite is mainly due to the addition of γ-alumina. The calcium adsorption capasity increased from 0.5 mg/g to 1.15 mg/g when the initial ion concentration was raised from 60 ppm to 100 ppm. The adsorption capacity of 1.15 mg/g and removal % of 23 with were obtained for optimal initial concentration of 100 ppm, adsorbent dosage of 20 g.l−1, and composite percentage of bentonite/1 wt% γ-alumina. The adsorption mechanism was studied by the Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models, and the adsorption data was fitted better by the Freundlich model. The Dubinin-Radushkevich isotherm revealed the physical nature of the adsorption. Conclusively, the bentonite-1wt% γ-alumina nanocomposite had better results than the raw bentonite.

Sodium-mediated plateau potentials in an identified decisional neuron contribute to feeding-related motor pattern genesis in Aplysia.

Motivated behaviors such as feeding depend on the functional properties of decision neurons to provide the flexibility required for behavioral adaptation. Here, we analyzed the ionic basis of the endogenous membrane properties of an identified decision neuron (B63) that drive radula biting cycles underlying food-seeking behavior in Aplysia. Each spontaneous bite cycle arises from the irregular triggering of a plateau-like potential and resultant bursting by rhythmic subthreshold oscillations in B63's membrane potential. In isolated buccal ganglion preparations, and after synaptic isolation, the expression of B63's plateau potentials persisted after removal of extracellular calcium, but was completely suppressed in a tetrodotoxin (TTX)- containing bath solution, thereby indicating the contribution of a transmembrane Na+ influx. Potassium outward efflux through tetraethylammonium (TEA)- and calcium-sensitive channels was found to contribute to each plateau's active termination. This intrinsic plateauing capability, in contrast to B63's membrane potential oscillation, was blocked by the calcium-activated non-specific cationic current (ICAN) blocker flufenamic acid (FFA). Conversely, the SERCA blocker cyclopianozic acid (CPA), which abolished the neuron's oscillation, did not prevent the expression of experimentally evoked plateau potentials. These results therefore indicate that the dynamic properties of the decision neuron B63 rely on two distinct mechanisms involving different sub-populations of ionic conductances.