Adsorption Of Ca Research Articles

Thermodynamic Analysis of the Temperature Effect on Calcite Surface Reactions in Aqueous Environments

Reactive transport models for subsurface applications, particularly those for modified salinity waterflooding (MSW) in carbonates, have to be equipped with thermodynamic models that can reliably predict/describe adsorption phenomena at variable temperature conditions. To advance the understanding of the calcite reactivity at high temperatures, combining experimental and modeling studies is required. Therefore, we used a surface complexation model (SCM) to describe the reactivity at the calcite–water interface and obtained the enthalpies of the surface reactions by fitting the SCM either to high-temperature electrokinetic data obtained through streaming potential measurements on limestone samples or to the effluent concentration from single-phase flooding experiments. We assumed that the equilibrium constants of the surface reactions follow a temperature dependence according to van’t Hoff equation. Our calculations suggest that calcite protonation is more exothermic compared to other minerals (e.g., silica, hematite) and that the adsorption of Ca2+, Mg2+, and SO42– are all endothermic, with SO42– having the highest reaction enthalpy. We further show that the inferred enthalpies were in agreement with enthalpy changes from published microcalorimetry experiments. Despite the consistency with microcalorimetry data, the obtained enthalpies are not undisputable, and additional data are necessary to unequivocally constrain the temperature effect on the calcite surface reactivity.

Mild Reaction of Highly-Oriented Collagen Fibril Arrays with Simulated Body Fluid

The highly-oriented collagen fibrils that paralleled to one (rubbing) direction were fabricated by which the collagen molecular solution was spin-coated and self-assembled on the rubbed polyimide film. Subsequently, the hydroxyapatite crystals were precipitated on the collagen fibrils by immersing into simulated body fluid. In details, the carboxyl groups on the collagen fibrils were used as a reaction field for adsorption of Ca2+ ions and promoted the formation of hydroxyapatite crystals. As a result, the hydroxyapatite crystals grew along the a-axis leading to the formation of stable interfaces between hydroxyapatite crystals and collagen fibrils. Moreover, the oriented collagen fibril arrays were more useful for the nucleation and growth of hydroxyapatite. Therefore, we successfully fabricated the highly-oriented collagen fibril arrays which were useful for the precipitation of hydroxyapatite crystals.

Surface Free Energy, Interaction, and Adsorption of Calcium and Phosphate to Enamel Treated with Trimetaphosphate and Glycerophosphate

This study aimed to evaluate the surface (γs) and interaction (ΔGiwi) free energy and calcium (Ca2+) and phosphate (PO43−) adsorption to dental enamel treated with sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP) that had or had not been exposed to CaPO4-containing solutions. Bovine enamel blocks (n = 192; 24 blocks/group) were treated (2 mL/block; 2 min) with TMP (0%, 1%, 3%, and 9%) and CaGP (0, 0.25, 0.5, and 1%) or exposed to a CaPO4-containing solution. The adsorption of these compounds by enamel was assessed before and after treatment. γs and ΔGiwi and their apolar (γsLW and ΔGiwiLW) and polar (γsAB and ΔGiwiAB) components and acid-base interactions (γs+/γs−) were determined by the contact angles. The data were subjected to ANOVA, followed by the Student-Newman-Keuls test (p < 0.05). The adsorption of TMP was dose dependent (p < 0.001), and it reduced γs and γsAB and increased ΔGiwiAB (ΔGiwi > 0) and γs− when compared with the group without TMP (p < 0.001). The immersion in CaPO4-containing solution increased γs and γsAB and reduced ΔGiwiAB (ΔGiwi > 0) and γs− (p < 0.001). There was a correlation between the adsorption of TMP and Ca2+ (r = 0.916; p < 0.001) and PO43− (r = 0.899; p < 0.001). The adsorption of CaGP on the enamel was dose dependent (p < 0.001), reducing γs, ΔGiwiAB (ΔGiwi < 0), γsLW, and γs− when compared to the group without CaGP (p < 0.001). When exposed to the CaPO4-containing solution, there was an increase in ΔGiwiAB (ΔGiwi > 0), γsLW, and γs− and a decrease in γsAB (p < 0.001) without adsorption of Ca2+ by enamel. It may be concluded that TMP and CaGP were adsorbed onto the enamel, producing hydrophilic and hydrophobic surfaces, respectively. TMP produces electron donor sites that induce Ca2+ adsorption, while CaGP releases Ca2+ into the medium.

The Performance of Inorganic Salts/PMMA Nanocomposites in Ca and Mg Adsorption from Aqueous Solution

This study aimed to synthesize a new hybrid polymethyl methacrylate (PMMA) nanocomposites as catalysts in water treatment with high efficiency. We prepared three different materials, PMMA alone, then TiSO4/PMMA, and CaSO4/PMMA. After that, we made a screening experiment and found that TiSO4/PMMA was effective for Ca+2 removal and CaSO4/PMMA was effective for Mg+2 removal, and we made the optimization process according to this principle. The pH, contact time, dose, initial pollutant concentration, and temperature were performed to obtain the optimum parameters that achieve the highest Ca+2, Mg+2 removal efficiency as main cations causing hardness. The nanocomposite samples were characterized using different techniques. The CaSO4 nanoparticles were distributed uniformly across the CaSO4/PMMA matrix but TiSO4/PMMA has the parallel plate's morphology. Accordingly, the structures of the hybrids have been postulated. The maximum elimination value was 87.5% for Ca+2 and 65% for Mg+2. Adsorption isotherm and kinetics were demonstrated to set the nature of the reaction. Langmuir adsorption isotherm models were fitted with the experimental data for Mg+2 and Ca+2. The data of the pseudo-second-order kinetic model adequately fit the experimental values for the adsorption of Mg+2 and Ca+2. The positive values of ΔGo for Ca+2 (1.86 to 5.8 KJ/mol ) at all temperatures, and ΔGo for Mg+2 (1.5 KJ/mol) at 25oC indicated spontaneous adsorption process while the negative values for Mg+2 at 40oC and 60oC indicated a non-spontaneous adsorption process.

Graphitic carbon nitride nanosheet as an excellent compound for the adsorption of calcium and magnesium ions: theoretical and experimental studies

In this work, the removal of calcium (Ca2+) and magnesium (Mg2+) ions were studied using graphitic carbon nitride (g-C3N4) nanosheet as an adsorbent from aqueous solutions. In experimental studies, the effects of various adsorption parameters were investigated by batch method culture including pH, initial Ca2+ and Mg2+ concentrations, temperature, time, and adsorbent mass. The best results were obtained at pH=8.50, 0.05 g of g-C3N4, 90 min, 10 ppm of ion concentration, 23.80 mg g-1 of maximum adsorption capacity for Ca2+, and pH=9, 0.05 g of g-C3N4, 60 min, 15 ppm of ion concentration, 40.00 mg g-1 maximum adsorption capacity for Mg2+ ion. The adsorption of calcium and magnesium ions obeyed the Langmuir model on adsorbent. In theoretical study, g-C3N4 nanosheet as an interesting material was studied by first-principle calculation using the Quantum Espresso package. The Ca2+ and Mg2+ ions were located at different positions on g-C3N4 nanosheet to obtain the stable configuration. The Eads, HOMO, LUMO, Eg, band structure, DOS and PDOS plots were investigated at stable configuration of g-C3N4 nanosheet. The adsorption energy (Eads) was calculated -15.55 and -26.24 eV for Ca2+ and Mg2+ ions, respectively. Further, the results indicated that Mg2+can be located at the center of the porous g-C3N4 nanosheet, which the adsorption of Mg2+ on surface of g-C3N4 nanosheet was stronger than that of Ca2+ ion. Theoretical and experimental data confirmed each other’s findings. The adsorption of Ca2+ and Mg2+ ions was shown to be simple, high-yield, eco-friendly, and economical performance from aqueous solutions using g-C3N4 nanosheet

Synthesis of Hydrochar Cassava peels with hydrothermal carbonization method and applications as hard water softener

Groundwater before being used is very important to pay attention to the quality of the water. Water has good quality if it is in accordance with several parameters, including chemical, physical, and biological parameters. Mineral salt content is one of the chemical parameters that can be used to determine the quality of water. In this study, the synthesis of cassava peel hydrochar was successfully carried out using the hydrothermal carbonization (HTC) method. This material was developed to reduce waste of cassava peel biomass and overcome the problem of water hardness. HTC cassava peel was developed as an alternative hard water softener adsorbent. The results of FTIR characterization on hydro-activation (activating hydrochar) and hydro-non (non-activating hydrochar) contain functional groups of O-H stretch, C-H stretch, C≡C stretch and C=C stretch. Observation of surface morphology by SEM method on hydro-non in the form of large sheets, while the surface on hydro-activities in the form of small sheets. The adsorption capacity of hydro-active against Ca2+ ions and Mg2+ ions were 85.240 mg/g and 87.210 mg/g, respectively. Meanwhile, the hydro-non adsorption capacity of Ca2+ and Mg2+ ions were 84,736 mg/g and 85,713 mg/g. The kinetics of hydro-active adsorption on Mg2+ ion took place on order 3 (0.000003 min-1) while when adsorption of Ca2+ ion took place on order 0 (0.0324 min-1).©2021 JNSMR UIN Walisongo. All rights reserved.

A study on the mechanism of calcium ion in promoting the sedimentation of illite particles

Clay minerals are the main reason why coal slime water is difficult to settle. For the exploration of the influence of Ca2+ on the sedimentation effect of illite, the adsorption characteristics of illite were investigated under different Ca2+ concentrations. After adsorption equilibrium, the sedimentation test was carried out, and the changes in the surface properties of illite particles were analyzed by measuring Zeta potential and contact angle. The Theory of EDLVO was adopted to calculate the interaction energy between illite particles. The results showed that with the increase of Ca2+ concentration, the equilibrium adsorption capacity of illite increased, and the adsorption equilibrium was basically achieved at 60 min. The adsorption process was in accordance with the quasi-second-order kinetic model and Langmuir isothermal adsorption model. The sedimentation effect of illite was obviously improved after adsorption of Ca2+. When the concentration of Ca2+ was 10 mmol/L and pH = 8, the sedimentation rate was 92.5%. With the increase of Ca2+ concentration, the absolute value of the Zeta potential of illite after adsorption equilibrium decreased continuously, and the contact angle increased continuously. According to the Theory of EDLVO, the polar force is the dominant force affecting the interaction between particles. As the concentration of Ca2+ increases, the van der Waals attraction force between illite particles increases, the electrostatic and polar repulsive forces weaken, and the total interaction energy gradually decreases, indicating that Ca2+ can promote the agglomeration of illite particles, which is of benefit to the clarification of coal slime water.

Improving the Ca(II) adsorption of chitosan via physical and chemical modifications and charactering the structures of the calcified complexes

Chitosan (CS) has limited capacity for Ca(II)-adsorption abilities. Here, glutaraldehyde cross-linked chitosan (GLA-CTS) and maltose chitosan (MAL-CTS) were obtained by physical and chemical modifications to improve the adsorption of Ca2+. By comparing the adsorption kinetics and isotherm, the adsorption capabilities of GLA-CTS and MAL-CTS reached 112.27 ± 2.63 and 240.38 ± 31.88 mg/g in the presence of concentrations of 3000 mg/L Ca2+, which were about 2.1 and 4.6 times than CS. The structures of the resulting calcified complexes were profiled by SEM, XPS, FT-IR, and 13C NMR. Unlike the folds and spherical particles observed in CS-Ca(II) and GLA-CTS-Ca(II), the surface morphology of MAL-CTS-Ca(II) presented as flat-membrane-structures. In XPS assays, the peaks of Ca in GLA-CTS-Ca(II) and MAL-CTS-Ca(II) were significantly higher than that of CS-Ca(II), and the percentages of Ca atoms on the surfaces were 1.67 and 1.95 times higher respectively. Structural analyses were indicated from the FT-IR and 13C NMR results, the –NH2, –NHCOCH3 and –OH groups were all involved in the adsorption to Ca2+, and the worked groups were changed when calcium contents increased. Accordingly, possible structures of Ca(II)-complexes and the adsorption mechanisms were initially proposed. These two chitosan derivatives with evidently improved Ca(II)-adsorption are favorable for developing applications based chitosan.

Adsorption of Ca(II) and K(I) on the kaolinite surface: a DFT study with an experimental verification

The clay minerals have a negative influence on the settlement of coal tailings, and the addition of metal cations has a positive effect on treating coal tailings water. Microscopic adsorption mechanism of Ca(II) and K(I) on kaolinite surface was investigated by means of density functional theory (DFT) calculations and Monte Carlo method. The structures of Ca(II) and K(I) adsorption on kaolinite (001) and (00−1) was obtained, with Mulliken bond populations and binding energies calculated. Ca(II) adsorbed on kaolinite (001) surface and K(I) adsorbed on (00−1) surface are their main products, respectively, and the binding energies of all the adsorption products of Ca(II) are higher than those of K(I). Partial density of states projections combining with Mulliken bond charge and populations indicate that Ca−O and K−O bonds of the adsorption products are dominated by ionic interaction. Cation hydration can make the adsorption occurs more easily and enhance the covalent interaction of the bonds. The adsorption experiment verifies that Ca(II) is easier to adsorb on kaolinite than K(I).

Utilization of Charred Water Hyacinth (Jalkumvi) as Biosorbent for Removal of Ca(II) Ion from Aqueous Solution

A promising adsorbent, charred water hyacinth (CWH) for the removal of Ca(II) from the aqueous solution was explored by heat treatment of water hyacinth followed by chemical activation with acidified zinc chloride (ZnCl2). The adsorbent was characterized using scanning electron microscopy (SEM) and electron dispersive X-ray (EDX) spectroscopy. Batch adsorption techniques were conducted for Ca(II) adsorption to assess the adsorption isotherm, effect of pH, contact time, initial Ca(II) concentration, adsorbent doses, and adsorption kinetics. The SEM micrograph illustrates the rough and irregular surface morphology and EDX spectra confirm the successful adsorption of Ca(II) on the adsorbent surface. The equilibrium adsorption data better fitted to the Freundlich isotherm model having a maximum adsorption capacity (qmax) of 319.75 mg/g. The highest percentage of adsorption was found at pH 1.5. The adsorption of Ca(II) by CWH decreased at the higher metal concentration and lower adsorbent doses. The adsorption of Ca(II) ions onto CWH followed the pseudo-second-order kinetics model. . Overall, these results suggested that the as-prepared CWH can be used as an eco-friendly, economical and efficient alternative for the removal of Ca(II) from the aqueous solution.

DFT study of adsorption and diffusion of Mg, K, Ca over monolayer antimonene

Density Functional theory (DFT) based calculations are carried out to investigate adsorption and diffusion properties of Magnesium (Mg), Potassium (K) and Calcium (Ca) over single layer antimony (Sb) i.e. antimonene. Ca has highest value of absolute adsorption energy followed by K and Mg respectively. Charge transfer is greater in case of K adsorbed antimonene as compared to both of the other metals. This affects the electronic properties such as bandstructure and density of states. Antimonene is semiconducting in its pristine form. The adsorption of K leads to a shift to metallic nature, whereas Mg and Ca adsorption still maintain the semiconducting nature after reducing the bandgap. Diffusion of these metals shows that K can easily diffuse through the antimonene surface as compared to the Mg and Ca. The value of diffusion barrier for Mg, K and Ca is 0.30, 0.12 and 0.43 eV respectively. The effective adsorption and charge transfer along with low values of diffusion barrier suggests that phosphorene can be explored further as potential candidate for metal-ion batteries.

Effect of complex modification of Ca and Sb on the microstructure and mechanical properties of hypoeutectic Al-11Mg2Si alloy

The combined addition of 0.2 wt% Ca-Sb in Al-11Mg2Si alloy led to significant refinement of the eutectic Mg2Si from a coarse, needle-like morphology to spherical particles. Specifically, a further increase of Ca-Sb addition to 1.0 wt% resulted in the microstructure transition from hypoeutectic to hypereutectic characteristics. The refinement of eutectic Mg2Si could be attributed to the selective adsorption of Ca and Sb atoms on Mg2Si surfaces, which inhibited the growth of the eutectic phase in the preferential growth direction. Importantly, Ca and Sb elements were involved in the formation of heterogeneous nuclei for primary Mg2Si when Ca-Sb content increased to 1.0 wt%, which introduced the transition of composition from hypoeutectic to hypereutectic structures. Comparing to the unmodified alloy, the Al-11Mg2Si alloy modified with 0.2 wt% Ca-Sb exhibited significantly enhanced elongation to failure of ~7.9% (from ~1.3% of the unmodified alloy) and ultimate tensile strength of ~222 MPa (from ~180 MPa of unmodified alloy). The spheroidization of eutectic Mg2Si after complex modification is believed to be the underlying reason for the greatly enhanced tensile properties.

Synthesis and optimization selective ion-imprinted polymer for the elimination of Ca II ions using Taguchi design

One of the most important problems associated with calcium measurement is the possibility of underdiagnosed due to a false prediction of hypercalcemia results. Ion imprinting has become one of the fast growing technologies that have gained a lot of attention recently especially in the area of materials science. The present work proposes the synthesis and characterization of ion-imprinted polymer (IIP) in the form of porous film for the removal of Ca (II) from aqueous solution and human blood serum. Ca (II)-IIP films are prepared from mixing of two naturally formed biopolymers cellulose and sodium alginate, CaCl2, ECH, EDTA are used as the source of template ions, cross-linker and extraction agent, respectively. Taguchi method is used to optimize the synthesis and adsorption parameters of the new developed IIP. The optimum IIP films are characterized using FTIR, TGA, FESEM and XRD for determining the performance of the imprinting process achieved. PH dosage, initial concentration, reusability, selectivity, isotherm and kinetic study are investigated for the optimized IIP in Ca (II) aqueous solution. The resulted optimum conditions are pH 5.9, initial concentration (50 mg/l), dosage (300 mg) and 90 min contact time. It was clear from the adsorption data that the Ca (II) sorption by Ca (II)-IIP was fitted with the Langmuir isotherm model. The Langmuir adsorption constants for the adsorption of Ca (II) at room temperature are calculated to be (0.017 L/mg) and the R is 0.9469. The rate of removal of Ca (II) by Ca (II)-IIP is sustained between 98.99 and 86.12% for five periods. Furthermore, findings show that the Ca (II)-IIP is can successfully applied for the removal of free Ca (II) ions in human blood serum.

Esoteric CO adsorption by CuCl-NiCl2 embedded microporous MIL-101 (Cr)

A microporous MIL-101 (Cr) material with considerably high surface area of 3084 m2 g−1 and high total volume of 2.04 cm3 g−1 was used to host CuCl and NiCl2 species. Cu (II) was completely reduced to Cu (I) in the MIL-101 (Cr), while maintaining the Ni (II) in the host structures in order to effect the π-complexation between CO and the CuCl-NiCl2 MIL-101 (Cr) sample for improved CO adsorption. Ni (II) species were found to promote the reduction of Cu (II) and inhibit the agglomeration of copper crystals into large-size crystals, which enhanced the CO adsorption. The CuCl-NiCl2 MIL-101 (Cr) was capable of reaching a maximum CO adsorption of ca. ∼3.22 mmol g−1 and IAST-predicted CO/N2 selectivity of ca. ∼405. The sample was also regenerable for an extended period of time by a mere pressure swing without a post-treatment, making it a promising candidate for an industrial scale CO separation, enrichment and purification at ambient conditions.

A simulation on the graphyne and its inorganic BN-like nanosheets as anode materials for Ca-ion batteries

ABSTRACT Although the Li-ion batteries have some advantages, they have some disadvantages such as high cost, short life, and safety issues. Recently, Ca-ion batteries (CIB) have been suggested to replace Li-ion batteries due to calcium wide availability, multivalent character, and nontoxicity. Now, we evaluated the potential application of graphyne and its BN analogous (BN-yne) in the CIBs with the use of the B3LYP-gCP-D3 approach. The adsorption of Ca2+ and Ca on the graphyne is stronger and weaker than those on the BN-yne, respectively. The highest energy barrier for Ca2+ migration on the BN-yne (4.3 kcal/mol) is much lesser than that on the graphyne (5.9 kcal/mol) because of a strong cation-lone pair interaction in the BN-yne compared to the weak cation-π interaction of graphyne. Therefore, we realise the potential of the BN-yne in providing a greater Ca ion mobility and a more rapid charge/discharge rate compared to graphyne. Diffusion coefficient values calculated for the Ca2+ on the surface of graphyne and BN-yne are 3.27 × 10−11 and 5.14 × 10−9 cm2/s, and the predicted cell voltages are 3.38 and 3.66 eV, respectively. The results suggest that the BN-yne sheet may be a superior anode candidate for CIBs compared to the graphyne.

Excellent selectivity and high capacity of As (V) removal by a novel lignin-based adsorbent doped with N element and modified with Ca2+

As one of the most significant natural polymer with the highest annual yield, lignin has been applied in the treatment of wastewater to remove heavy metal ions. However, there are still some shortages, such as low reactivity, difficulties in adsorbing oxyanions and low selectivity on specific oxyanions. To improve its adsorption properties, a novel lignin-based adsorbent was prepared in this study, doped with nitrogen by Mannich reaction, using triethylenetetramine (TETA) as N source, and further modified with Ca2+. The adsorption of Ca, N-co-doped lignin (Ca@N-Lig) for As (V), Cr (VI) and P (V) was studied. The Ca@N-Lig shows high capacity, excellent selectivity and prominent regeneration ability for As (V) adsorption. The adsorption of Ca@N-Lig for As (V) followed the Langmuir isotherm model and the pseudo-second-order kinetics model, yielding a maximum adsorption capacity of 681.59 mg·g−1 and a fast adsorption equilibrium within 30 min. Ca@N-Lig has an excellent regeneration ability on the adsorption of As (V) with a decrease of about 15.60% after 5 adsorption/desorption cycles. This study offers an efficient way to remove As (V) from polluted water.

Bioactive glass doped with noble metal nanoparticles for bone regeneration: in vitro kinetics and proliferative impact on human bone cell line.

This work investigates the bioactivity of novel silver-doped (BG-Ag) and gold-doped (BG-Au) quaternary 46S6 bioactive glasses synthesized via a semi-solid-state technique. A pseudo-second-order kinetic model successfully predicted the in vitro uptake kinetic profiles of the initial ion-exchange release of Ca in simulated body fluid, the subsequent Si release, and finally, the adsorption of Ca and P onto the bioactive glasses. Doping with silver nanoparticles enhanced the rate of P uptake by up to approximately 90%; whereas doping with gold nanoparticles improved Ca and P uptake rates by up to about 7 and 2 times, respectively; as well as Ca uptake capacity by up to about 19%. The results revealed that the combined effect of Ca and Si release, and possibly the release of silver and gold ions into solution, influenced apatite formation due to their effect on Ca and P uptake rate and capacity. In general, gold-doped bioactive glasses are favoured for enhancing Ca and P uptake rates in addition to Ca uptake capacity. However, silver-doped bioactive glasses being less expensive can be utilized for applications targeting rapid healing. In vitro studies showed that BG, BG-Ag and BG-Au had no cytotoxic effects on osteosarcoma MG-63 cells, while they exhibited a remarkable cell proliferation even at low concentration. The prepared bioactive glass doped with noble metal nanoparticles could be potentially used in bone regeneration applications.

New insight of Ca element refining grain structure in commercial purity Mg based on the first-principle calculation

ABSTRACT The first-principle calculation was used to understand new insight of Ca element refining grain structure in commercial purity Mg. Negative adsorption energy, strong ionic bond and negative shift of partial density of states verify that Ca element is readily adsorbed on the surface of MgO. Combined with analysis of interfacial bonding between Mg2Ca and α-Mg, new insight of Mg2Ca layer formed via Ca adsorption efficiently nucleating α-Mg was proposed. Adsorption of other alkaline earth elements (Be, Sr or Ba) and the crystallographic feature of Be, Mg17Sr2 and Mg17Ba2 along with the experimental results further consolidate new insight of Ca element refining grain structure in commercial purity Mg.

A first-principles comparative study of lithium, sodium, potassium and calcium storage in two-dimensional Mg2C

Two-dimensional (2D) materials have recently emerged as potential candidates for high-capacity lithium-ion batteries anode materials because of their compelling physicochemical and structural properties. In the present study, we use first-principles calculations to investigate the performance of 2D Mg2C as anode materials for Li, Na, K and Ca-ions batteries. The calculated average open-circuit voltage are 0.37, 0.50, 0.03 and 0.06 eV vs Li, Na, K, Ca. No significant structural deformations are observed on the 2D Mg2C upon the adsorption of Li, Na, K or Ca and the metallic characteristic of the 2D Mg2C is retained. The metallic behaviour of both pristine and adsorbed Mg2C ensures the desirable electric conductivity, implying the advantages of 2D Mg2C for batteries. The Na and K atoms show an extremely high diffusivity on the 2D Mg2C with a low energy barrier of 0.08 and 0.04 eV respectively, which is about an order of magnitude smaller than that of Li atom. For the Na and K atoms, the theoretical storage capacity can reach up to 1770 mAh g−1, nearly two times that of the Li atom of 885 mAh g−1. Our study suggests that the 2D Mg2C is a promising anode material which offers a fast ion diffusion and high storage capacity.

Preparation and characterization of activated carbon developed from cotton cloth residue activated with phosphoric acid: adsorption of clofibric acid.

Cotton cloth waste was used as a precursor to prepare activated carbon (ACCs) chemically activated with phosphoric acid. Adsorption behavior of prepared ACCs was correlated with physicochemical proprieties. The pore volume and BET surface of ACCs were determined by nitrogen adsorption isotherms and scanning electron microscopy was used to observe their surface morphologies. Fourier transform infrared (FTIR) spectroscopy analysis and pH point zero charge (pHPZC) were conducted to determine chemical properties. Under the optimal conditions: 50% impregnation ratio and thermal treatment under N2 flow at 600 °C during 60 min, the activated carbon prepared exhibits a high surface area 1,150 m2/g, 0.501 cm3/g micropore volume and an excellent adsorption performance. The adsorbed amount of clofibric acid is found to be 9.98 and 83 mg/g at, respectively, initial CA concentration of 10 and 100 mg/L at pH 3.0 and 20 °C. Diffusion and chemisorption are the steps controlling the adsorption of CA onto ACC 50% and the equilibrium data were well described by Freundlich isotherm.