Adsorptive Removal of Manganese Ions from Polluted Aqueous Media by Glauconite Clay-Functionalized Chitosan Nanocomposites

The presence of Mn(II) in water exceeding the permitted concentration limits declared by the World Health Organization (WHO) influences individuals, animals, and the ecosystem negatively. Therefore, there is a necessity for an efficient material to eliminate this potentially toxic element from wastewater. We herein focused on the adsorptive removal of Mn(II) ions from polluted aqueous media using natural Egyptian glauconite clay (G) and its nanocomposites with modified chitosan (CS). We applied modified chitosan with glutaraldehyde (GL), ethylenediaminetetraacetic acid (EDTA), sodium dodecyl sulfate (SDS), and cetyltrimethyl ammonium bromide (CTAB). The utilized nanocomposites were referred to as GL-CS/G, EDTA-GL-CS/G, SDS-CS/G, and CTAB-CS/G, respectively. The point of zero charge values of the materials were estimated. The adsorption properties of the G clay and its nanocomposites toward the removal of Mn(II) ions from polluted aqueous media as well as the adsorption mechanism were explored using a batch technique. The glauconite (G) and its nanocomposites: GL-CS/G, CTAB-CS/G, EDTA-GL-CS/G, and SDS-CS/G, exhibited maximum adsorption capacity values of 3.60, 24.0, 26.0, 27.0, and 27.9 mg g^?1, respectively. The adsorption results fitted well the Langmuir isotherm and pseudo-second-order kinetic models. The estimated thermodynamic parameters: ΔH° (from 1.03 to 5.55 kJ/mol) and ΔG° (from ? 14.5 to ? 18.8 kJ/mol), indicated that Mn(II) ion adsorption process was endothermic, spontaneous, and physisorption controlled. Furthermore, the obtained adsorption results are encouraging and revealing a great potentiality for using the modified adsorbents as accessible adsorbents for Mn(II) ion removal from polluted aqueous solutions, depending on their reusability, high stability, and good adsorption capacities.

Graphic Abstract

     

Structural,Microstructure, Mechanical and Electrical Properties of Porous Zr4+-Cordierite Ceramic Composites

Zirconium-cordierite ceramic composites have been synthesized by a co-precipitation method using MgCl₂·6H₂O, NaAlO₂, Na₂SiO₃·5H₂O, and ZrOCl₂·8H₂O as starting materials. XRD, FT-IR, and SEM techniques were employed to study the effect of zirconium on the crystal structure and microstructure of the samples. XRD results revealed that spinel MgAl₂O₄ and t-ZrO₂ phases were predominant in the samples with low Zr⁴⁺ content (10 wt.%), whereas zircon ZrSiO₄ was predominant with high Zr⁴⁺ content (≥15 wt.%). The densification behavior was improved from 30.4 to 44.6% of the theoretical density (2.6 g/cm³) at 15 wt.% of Zr⁴⁺. However, microhardness of the sintered samples was enhanced from 7.1 to 7.5 GPa with increasing the Zr⁴⁺ dose from 0 to 25 wt.%. On the other hand, the gradual increase in Zr⁴⁺ content from 0 to 25 wt.% led to suppression in the electrical resistivity (ρ) from 16.6 to 2.8 × 10⁹ Ω/cm, respectively. In addition, the dielectric permittivity (ε) of the pure cordierite was decreased with Zr⁴⁺ ion addition. The maximum dielectric permittivity (ε) at low frequencies (10 MHz) was 18.7 at 10 wt.% Zr⁴⁺ content, whereas at high frequencies (1 GHz) it was 38.8 at 15 wt.% Zr⁴⁺ content.     

Making concrete with saline well-water

Permitted limits of salt concentrations in water used for making mortar and plain concrete differ from one country to another, but in any event geographical conditions prevent this guidance being applied directly to Saudi Arabia. Comparing the effects on compressive strength of saline well-water and drinking quality water, scientists at the Department of Building Research in the Saudi Arabian Standards Organisation show in this article that well-water with total dissolved salts (TDS) concentrations up to 4500 ppm can be suitable for mixing and curing mortars and plain concrete.     

Oxidative desulfurization using graphene and its composites for fuel containing thiophene and its derivatives: An update review

Oxidative desulfurization, in which the aromatic sulfur containing compounds are oxidized to their analogical sulfones and subsequently extracted, has assured to be one of the exceedingly effective desulfurization processes for resulting ultra-low sulfur import fuels. The oxidative desulfurization process using graphene oxide has attracted significant interest for sulfur removal from fuels. In this survey, we discussed systematically the techniques of desulfurizations in catalytic oxidation, including the role of graphene as a supported catalyst, the research results of oxidative desulfurization using graphene oxide and provided the factors affecting the desulfurization process. We also debate the challenges counterattack the use of graphene oxide in this view, including their preparation methods and their efficiency and stability as a supported catalyst. Also, there are some of the desulfurization processes currently under investigation such as oxidation, biodesulfurization, and adsorption was outlined in brief. The combustion of fossil fuels containing sulfur compounds emits some of the sulfur oxides which considered a harmful influence on human health and the surrounding environment as well as the economy. It can be concluded that GO remains a kind of ideal supported catalysts to recognize a pure fuel in the near futurity due to their eligible physicochemical characteristics.     

Adsorption of 141Ce(III), 160Tb(III), and 169Yb(III) on the Synthesized Inorganic Ion Exchanger,Zirconium Titanium Phosphate

Radiochemistry - Samples of zirconium titanium phosphate inorganic ion exchangers with different Zr : Ti molar ratios were synthesized. The samples were characterized using FT-IR spectroscopy,...     

Characterization of gamma irradiated plasticized starch/poly(vinyl alcohol) (PLST/PVA) blends and their application as protected edible materials

Blends based on different ratios of plasticized starch (PLST) and poly(vinyl alcohol) (PVA) were prepared in the form of thin films by casting solutions. The effect of gamma-irradiation on thermal, mechanical and morphological properties was investigated. The results of thermogravimetric analysis (TGA), in terms of weight loss and rate of reaction, indicated that the thermal stability of PLST/PVA blends is higher than pure PLST. The differential scanning calorimetry (DSC) scans do not show the glass transition temperature (T_g) of PVA or PLST, but instead a new single glass transition, indicating the occurrence of compatibility. The mechanical testing of PLST/PVA blends showed that tensile strength and elongation at break were increased by increasing the ratio of PVA. At any ratio of PLST/PVA, the tensile strength and elongation at break was found to increase with increasing irradiation dose. As an application in the field of prolonging food preservation lifetime, solutions of gamma irradiated PLST/PVA blends in the presence of chitosan, as an antimicrobial material, were applied to Mango fruits by surface coating. The results showed that this technique would provide suitable materials for food preservation that withstanding the temperature and stresses.     

Bladeless Wind Turbine as Wind Energy Possible Future Technology

Access to clean energy is a fundamental need, yet it is by all accounts an extravagance only a few can afford.     

Corrosion inhibition of nickel in H2SO4 solution by alanine

The effect of alanine, as a safe inhibitor, was studied by measuring the corrosion of Ni in aerated and stagnant 1 M H₂SO₄ solution (pH ～0.2). Measurements were performed under various conditions using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and the new electrochemical frequency modulation (EFM) methods. The obtained results showed that the addition of alanine alone gives a moderate inhibition and acts as an anodic-type inhibitor. The inhibition is due to physical adsorption of alanine on the metal surface. The inhibition efficiency enhances with increasing alanine concentration and immersion time but decreases with rise in temperature. The apparent activation energy, E_a, is higher in the presence than in the absence of alanine. Addition of I^? ions greatly improves the inhibition efficiency of alanine. The synergistic effect is due to enhanced adsorption of alanine cations by chemisorbed I^? anions on the metal surface. The results obtained from polarization, EIS and EFM techniques are in good agreement indicating that EFM method can be used successfully for monitoring corrosion rate of Ni in H₂SO₄ solution with and without alanine.     

Optical and electrical properties of Y3+ ion substituted orthorhombic mullite Y(x)Al(6−x) Si2O13 nanoparticles

Y³⁺ substituted mullite Y_(x)Al_(6?x)Si₂O₁₃ nanoparticles where x varied from 0.005 to 0.05 have been synthesized via co-precipitation technique. X-ray diffraction results revealed that orthorhombic mullite was the major phase in the samples of x = 0.0–0.025, whereas corundum α-Al₂O₃ was predominant at high Y³⁺-ion content of x = 0.05. Transmission electron microscope images showed orthorhombic-like structure for the pure sample. Meanwhile, the doped samples exhibited similar morphologies of larger particle sizes associated with small amount of glassy liquid phase. FT-IR spectrum evinced the formation of corundum particularly at high Y³⁺ ion content (5 %). The photoluminescence emission spectra were strongly affected by the Y³⁺ ion content. Moreover, mullite sample doped with 0.5 % Y³⁺ ion achieved the minimum electrical resistivity of 0.28 × 10⁹ Ω cm and the minimum dielectric loss value of 0.37 in the radiowave frequency region (10 MHz) as well as the minimum dielectric loss value of 0.41 in the microwave frequency region (1 GHz).     

Acetylacetone phenylhydrazone functionalized polyurethane foam: Determination of copper,zinc and manganese in environmental samples and pharmaceutics using flame atomic absorption spectrometry

In the present work, acetylacetone phenylhydrazone (AAPH) was chemically anchored to polyurethane foam (PUF) via azo coupling of the toluidine NH₂ in PUF to active CH₂ in acetylacetone (AA) and further reaction to phenylhydrazine to give new solid phase extraction (SPE) sorbent for determination of Cu(II), Zn(II) and Mn(II) in natural and pharmaceutical samples. The AAPH–PUF was characterized by UV–VIS, IR, H¹ NMR, elemental and TGA analysis. Optimal experimental conditions were at pH 5–6, shaking time 20 min, sample flow rate 1.0 mL min^?1, and desorption by 10 mL from 0.5 mol L^?1 hydrochloric acid. The limit of detection (3σ) was found to be 0.10, 0.12 and 0.19 μg L^?1 for Cu(II), Zn(II) and Mn(II), respectively. A preconcentration factor of 100 has been achieved for all elements. Precision (RSD%) was found to be 6.3%, 5.3% and 3.2% (n = 5), respectively. Successful application was achieved for environmental samples (tap water, olive leaves, and fish liver) and pharmaceutical formulation. The obtained recovery varied between 90.8% and 96.8% and RSD was under 6.7%.