Mono and Poly-Cationic Adsorption of Heavy Metals Using Natural Glauconite

Advanced nano modification of ecofriendly glauconite clay for high efficiency methylene blue dye adsorption

This research focuses on the utilization of nano glauconite clay as an environmentally friendly sorbent for the removal of cationic dyes, particularly Methylene Blue (MB), from polluted water. The glauconite clay was sourced from the El Gidida region of Egypt and subjected to grinding in a laboratory-type ball mill to ensure homogeneity and increase the active sites available for the adsorption process. The resulting ball milled nano clay (BMNC) was characterized using techniques such as X-ray fluorescence (XRF), Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The concentration of MB dye was monitored using UV-Vis spectroscopy to assess the adsorption capacity of BMNC under various conditions including pH, time, dose, and temperature. The optimal conditions for the adsorption process were determined to be a pH range of 7-8, a contact time of 60 min, and a dose of 200 ppm, resulting in an adsorption capacity of 128 mg/g. This process demonstrated both low cost and high speed. The adsorption mechanism of MB on the BMNC surface was evaluated through kinetics, adsorption isotherms, and thermodynamics. The experimental data indicated an endothermic, spontaneous, and thermodynamically favourable adsorption process, which was further supported by simulated modelling results using Forcite program. The in-silico data aligned well with the experimental findings. Additionally, the study assessed the interference of salts, metal ions, and other dyes on MB adsorption onto BMNC, showing promising results. These findings strongly support the effectiveness of our sorbent substrate under challenging conditions.

Enhanced remediation of U(vi) ions from water resources using advanced forms of morphologically modified glauconite (nano-sheets and nano-rods): experimental and theoretical investigations

Two forms of morphologically transformed glauconite (GL) involved exfoliated nanosheets (EXG) and nanorods (GRs), which were synthesized by facile exfoliating and scrolling modification under sonication. The two advanced forms (EXG and GRs) were applied as enhanced adsorbents for U(vi) ions and compared with using raw glauconite. The developed GRs structure displays higher saturation retention properties (319.5 mg g-1) in comparison with both EXG (264.8 mg g-1) and GL (237.9 mg g-1). This enhancement is assigned to the noticeable increment in the surface area (32.6 m2 g-1 (GL), 86.4 m2 g-1 (EXG), and 123.7 m2 g-1 (GRs)) in addition to the surface reactivity and exposure of effective siloxane groups. This was supported by the steric investigation based on the isotherm basics of the monolayer model of one energy site. The steric functions declared a strong increase in the density of the existing effective uptake receptors throughout the modification stages (GRs (112.1 mg g-1) > EXG (87.7 mg g-1) > 72.5 mg g-1 (GL)). Also, each active site can be filled with 4 U(vi) ions, donating the parallel orientation of these ions and the operation of multi-ionic mechanisms. The energetic functions, either the uptake energy (<13 kJ mol-1) or Gaussian energy (<5 kJ mol-1), validate the retention of U(vi) by physical reactions. These reactions displayed spontaneous properties and exothermic behaviors based on the investigated thermodynamic functions, including entropy, enthalpy, and internal energy. The structures also showed significant recyclability, indicating potential application on a realistic and commercial scale.

Synthesis and Characterization of Iron-Rich Glauconite Nanorods by a Facile Sonochemical Method for Instantaneous and Eco-friendly Elimination of Malachite Green Dye from Aquatic Environments

Novel glauconite nanorods (GNRs) were synthesized by the sonication-induced chemical expansion and scrolling process of natural glauconite. The synthetic nanostructure was characterized by different analytical techniques as a superior adsorbent for the malachite green dye (MG). The synthetic GNRs were detected as porous nanorods with an average length of 150 nm to 5 μm, an average diameter of 25 to 200 nm, and a specific surface area of 123.7 m2/g. As an adsorbent for MG, the synthetic GNRs showed superior uptake capacity up to 1265.6 mg/g at the saturation stage, which is higher than most of the recently developed highly adsorbent dyes. The adsorption behavior and mechanistic properties were depicted by using modern and traditional equilibrium modeling. The kinetic assumption of the pseudo-first-order model (R2 > 0.94) and the classic isotherm of the Langmuir equilibrium model (R2 > 0.97) were used to describe the adsorption reactions. The steric investigation demonstrates that each active site on the surface of GNRs can adsorb up to three MG molecules (n = 2.19-2.48) in vertical orientation involving multimolecular mechanisms. Also, the determined active site density (577.89 mg/g) demonstrates the enrichment of the surface of GNRs with numerous adsorption receptors with strong affinity for the MG dye. The energetic study, including Gaussian energy (6.27-7.97 kJ/mol) and adsorption energy (9.45-10.43 kJ/mol), revealed that GNRs had physically adsorbed the dye, which might involve electrostatic attraction, hydrogen bonding, van der Waals forces, and dipole forces. The internal energy, enthalpy, and entropy determined the exothermic and spontaneous uptake of MG.

Soil Organic Matter Composition and pH as Factors Affecting Retention of Carbaryl, Carbofuran and Metolachlor in Soil

The majority of studies concerning the environmental behavior of hydrophobic pollutants in soil consider soil organic matter (SOM) content as a main factor influencing chemical retention, whereas the composition of SOM and its individual fraction share are often neglected. In the present paper, carbaryl, carbofuran and metolachlor retention by loamy sand and loam topsoil materials is compared and referred to humic acids (CHA) and the residual carbon (CR) content of SOM. Additionally, the sorption-desorption behavior of agrochemicals in soils was tested at a pH of three to seven. Calculated isothermal parameters point to favorable, spontaneous and physical pesticide sorption. Groundwater ubiquity score (GUS) indexes confirmed the low leaching ability of metolachlor on soils and moderate of carbofuran. The high affinity of carbaryl to CR may explain its pronounced sorption in loam soil and the lowest percolation potential. Carbofuran retention in soils was associated with montmorillonite (Mt) and CR fractions. Meanwhile, metolachlor uptake was related to humic acid and Mt content of the soils. Lower pH enhanced retention of the agrochemicals, except for carbaryl sorption in sandy loam soil. Results of this study highlight that SOM composition and mutual share of individual organic carbon fractions alongside pH may play a crucial role in predicting non-ionic pesticide behavior in soil.

Polyaniline/Glauconite Nanocomposite Adsorbent for Congo Red Dye from Textile Wastewater

Glauconite (Gl), a naturally occurring clay material, was utilized as an affordable and ecologically friendly adsorbent to explore its capturing capacity towards Congo red (CR) dye from textile industrial waste effluent. To improve adsorption and removal effectiveness, a modification technique utilizing polyaniline (PAN) was investigated. An X-ray diffractometer (XRD), a scanning electron microscope (SEM), and Fourier transformer infrared (FTI-R) were applied as strong familiar characterization techniques for all used adsorbents. The effects of starting concentration, contact duration, adsorbent dose, pH, and temperature on the adsorption process were also studied. The reusability of the adsorbent was studied over four adsorption cycles. The results show that PAN modification of Gl enhances the effectiveness of CR elimination. The clearance efficiency of raw and modified glauconite at 25 °C and pH 7 was 77% and 91%, respectively. The kinetics and isotherms of Congo red dye adsorption were investigated using batch studies to determine the impacts of various experimental conditions. The maximum adsorption capacity of the glauconite/polyaniline (Gl/PAN) nanocomposite rose from 11.9 mg/g for Gl to 14.1 mg/g in accordance with the isotherm analysis, which shows that the Langmuir isotherm properly characterizes the experimental data. The pseudo-second-order model (R2 = 0.998) properly expresses the experimental data. The reusability research proved that the adsorbents may be reused effectively. The overall results suggest that the modified Gl by PAN might be used as a low-cost, natural adsorbent for eliminating CR color from textile effluent.

The Characterization of Ukrainian Volcanic Tuffs from the Khmelnytsky Region with the Theoretical Analysis of Their Application in Construction and Environmental Technologies

(1) The mineral deposits are the base resources of materials used in building and environmental engineering applications, especially available locally. Two wells of volcanic tuff deposits in the Khmelnytsky region of Ukraine were investigated in this regard. (2) Physical-mechanical, chemical, and mineralogical analyses of the core samples were carried out. (3) The tuff samples were characterized by visible colour, low compressive strength (4.34–11.13 MPa), and high water absorption (30%). The dominant minerals of the upper horizon were chlorite, pyroxene, kaolinite, quartz, hematite, and calcite, while those of the lower horizon included analcime, quartz, hematite, and calcite. (4) The studied volcanic tuffs seem to be only partly useful for construction applications, and considering their visible colour, the exterior decoration of engineering objects could be possible. The peculiarity of the minerals of the upper horizon is that their crystals consist of Fe²⁺. An analysis of existing scientific data made it possible to say that these minerals can be considered as an alternative to expensive metallic iron in reducing the toxicity of chromium, uranium, and halogenated organic compounds. The significant presence of hematite allows the application of tuffs to technologies of water purification from As⁵⁺, As³⁺, Cr⁶⁺, Cr³⁺, U⁶⁺, Sb⁵⁺, and Se⁴⁺ oxyanions.

Application of ural glauconite for groundwater deironing and demanganation

Heavy metals are among the most common pollutants affecting biological systems when ingested with drinking water and food. Heavy metal ions are capable of bioaccumulation in a human body and could cause various metabolic disorders. Here we present the results of using a unique glauconite from the Barguzinsky deposit as an adsorbent for heavy metals. The physicochemical properties of glauconite samples, including the specific surface area, specific pore volume, zeta potential, thermal and elemental analyses and scanning electron microscopy of the surface were studied for different fraction sizes. The sorption properties of the glauconite samples were studied under static conditions for extraction of iron and manganese ions from model solutions. Analysis of the content of the detected ions in solutions and filtrates was performed by the methods of stripping voltammetry. We revealed high sorption properties of glauconite for iron elimination, but comparatively lower ones in removing manganese.

Treatment of Water Contaminated with Reactive Black-5 Dye by Carbon Nanotubes

Most of the dyes used today by the textile industry are of synthetic origin. These substances, many of which are highly toxic, are in many cases not adequately filtered during the processing stages, ending up in groundwater and water courses. The aim of this work was to optimize the adsorption process of carbon nanotubes to remove an azo-dye, called Reactive Black-5, from aqueous systems. Particular systems containing carbon nanotubes and dye solutions were analyzed. Furthermore, the reversibility of the process and the presence of possible degradation phenomena by the dye molecules were investigated. For this purpose, the influence of different parameters on the adsorption process, such as the nature of the carbon nanotubes (purified and nonpurified), initial concentration of the dye, stirring speed, and contact times, were studied. The solid and liquid phases after the tests were characterized by chemical-physical techniques such as thermogravimetric analysis (TG, DTA), UV spectrophotometry, BET (Brunauer, Emmett, Teller), and TOC (total organic carbon) analysis. The data obtained showed a high adsorbing capacity of carbon nanotubes in the removal of the Reactive Black-5 dye from aqueous systems. Furthermore, the efficiency of the adsorption process was observed to be influenced by the stirring speed of the samples and the contact time, while purified and nonpurified nanotubes provided substantially the same results.

Sorption of Heavy Metal Ions of Chromium, Manganese, Selenium, Nickel, Cobalt, Iron from Aqueous Acidic Solutions in Batch and Dynamic Conditions on Natural and Synthetic Aluminosilicate Sorbents

Zeolites are materials with known sorption properties. The sorption is thought to progress mainly by ion exchange with Na⁺, K⁺, Mg²⁺, Ca²⁺ or H⁺ from the zeolite exchange sites. The aim of the study was to compare the sorption properties of natural and synthetic zeolites on the example of the removal of selected metals from aqueous acidic solutions. Uptake experiments for selected ions of chromium, manganese, selenium, nickel, cobalt, and iron were performed using the batch and kinetic column methods. The sorption of the individual metal ions in mg per 1g of sorbent was determined for each sorbent. The relative affinity sequence of the examined cations toward the various sorbent was presented. The Langmuir model was used to model the adsorption equilibrium. Vermiculite under 1 mm of diameter (SF), Na-X, and Na-A were proved to be the most suitable for the individual uptake of studied metal ions. It was observed that the behavior of selenium ions differed from the remaining ones which was interpreted that selenium undergoes adsorption in the anionic form. The fixed-bed column studies were performed using Na-A, ensuring the sorption of selenium in the presence of iron(III) ions. The experiments were conducted using Na-X zeolite pre-loaded by Fe(III) as well as unmodified sorbent eluted by an equimolar mixture containing 100 ppm of Fe and Se. Obtained results prove that selenium sorption improves if other metal ions such as iron appear in the acidic solution. That efficient selenium sorption conditions can be applied to remove selenium which was recognized as toxic at higher levels.

Studying glauconite of the bakchar deposit (Western Siberia) as a prospective sorbent for heavy metals

Glauconite is one of natural clay minerals that are low-cost and readily available. Its specific characters, including potassium cations activity, layered structure and absorption capacity, explain the comprehensive interest to this mineral. It is especially prospective in regard of water treatment. Glauconite composition depends on the formation conditions, which lead to different sorption properties. Here we studied the sorption parameters and physical characteristic of unique glauconite of the Bakchar deposit by mean of granulometric analysis, electromagnetic separation, X-ray fluorescence analysis, inductively coupled plasma-mass spectroscopy, petrographic studies, scanning electron microscopy, X-ray diffraction analysis, nitrogen thermal desorption method, inversion voltammetry. Finally, we tested this mineral as a sorbent. The studied glauconitic concentrate has the best comparative sorption properties. Results show that glauconite of the Bakchar deposit is a cheap and prospective sorbent for heavy metals.

Mineral Materials Coated with and Consisting of MnOx-Characteristics and Application of Filter Media for Groundwater Treatment: A Review

For groundwater treatment, the technologies involving oxidation on MnOx filter bed are beneficial, common, and effectively used. The presence of MnOx is the mutual feature of filter media, both MnOx-coated mineral materials like quartz sand and gravel, chalcedonite, diatomite, glauconite, zeolite, or anthracite along with consisting of MnOx manganese ores. This review is based on the analysis of research and review papers, commercial data sheets, and standards. The paper aimed to provide new suggestions and useful information for further investigation of MnOx filter media for groundwater treatment. The presented compilations are based on the characteristics of coatings, methods, and conditions of its obtaining and type of filter media. The relationship between the properties of MnOx amendments and the obtained purification effects as well as the commonly used commercial products, their features, and applications have been discussed. The paper concludes by mentioning about improving catalytic/adsorption properties of non-reactive siliceous media opposed to ion-exchange minerals and about possible significance of birnessite type manganese oxide for water treatment. Research needs related to the assessment of the use MnOx filter media to heavy metals removal from groundwater in field operations and to standardize methodology of testing MnOx filter media for water treatment were identified.

Removal of Zinc from Aqueous Solutions Using Lamellar Double Hydroxide Materials Impregnated with Cyanex 272: Characterization and Sorption Studies

Removal of heavy metals from wastewater is mandatory in order to avoid water pollution of natural reservoirs. In the present study, layered double hydroxide (LDH) materials were evaluated for removal of zinc from aqueous solutions. Materials thus prepared were impregnated with cyanex 272 using the dry method. These materials were characterized through X-ray diffraction (XRD), Fourier transform infrared (FTIR), and thermal analysis. Batch shaking adsorption experiments were performed in order to examine contact time and extraction capacity in the removal process. Results showed that the equilibrium time of Zn (II) extraction is about 4 h for Mg₂Al-CO₃ and Mg₂Al-CO₃-cyanex 272, 6 h for Zn₂Al-CO₃, and 24 h for Zn₂Al-CO₃-cyanex 272. The experimental equilibrium data were tested for Langmuir, and Freundlich isotherm models. Correlation coefficients indicate that experimental results are in a good agreement with Langmuir’s model for zinc ions. Pseudo-first, second-order, Elovich, and intraparticular kinetic models were used to describe kinetic data. It was determined that removal of Zn²⁺ was well-fitted by a second-order reaction kinetic. A maximum capacity of 280 mg/g was obtained by Zn₂Al-CO₃-cyanex 272.

Potassium and Metal Release Related to Glaucony Dissolution in Soils

Plant nutrients such as potassium (K) may be limited in soil systems and additions (i.e., fertilizer) are commonly required. Glaucony is a widely distributed and abundant marine-derived clay mineral present in soils worldwide which may serve as a source of potassium. The South Island of New Zealand contains numerous deposits of glaucony-rich rocks and related soils providing an opportunity to explore how glaucony might be a beneficial source of potassium. Here, the geochemistry of glaucony and its suitability as a mineral source of soil K from four deposits in New Zealand was examined using spatially resolved chemical analyses and dissolution experiments. Geochemical and morphological analyses revealed that glaucony from all deposits were K-enriched and were of the evolved (6%–8% K2O) to highly evolved type (>8% K2O). Glaucony derived from growth inside pellets contain elevated K and Fe concentrations compared to bioclast-hosted glaucony. Solubility analysis showed that K was released from glaucony at rates higher than any other metal present in the mineral. Additionally, decreasing the pH and introducing an oxidizing agent (i.e., birnessite which is ubiquitous in soil environments) appeared to accelerate K release. Trace metals including Cr, Zn, Cu, and Ni were present in the solid phase analysis; however, further investigation with a focus on Cr revealed that these elements were released into solution at low concentrations and may present a source of soil micronutrients. These results suggest that glaucony may offer a source of slow releasing K into soils, and so could be used as a locally sourced environmentally sustainable K resource for agriculture, whether in New Zealand or worldwide

Adsorption of Ni2+ and Cd2+ from Water by Calcium Alginate/Spent Coffee Grounds Composite Beads

The use of heavy metals in technological applications has led to detrimental effects on human health and the environment. Activated carbon and ion-exchange resins are commonly used to remove pollutants but they are expensive. Therefore, the research of low-cost alternatives derived from natural resources and organic wastes is being considered. The aim of this study considers the use of Calcium Alginate/Spent Coffee Grounds (CA–SCGs) composite beads to adsorb heavy metals from aqueous solutions, particularly, the removal of Ni2+ or Cd2+ at concentrations from 10 ppm to 100 ppm. CA–SCGs beads were made of equal proportions of alginate and spent coffee grounds and compared with calcium alginate beads (CA beads) and spent coffee grounds (SCGs) in terms of capacity and rate of adsorption. Three cycles of adsorption/desorption were done. The beads were characterized by Scanning Electron Microscopy coupled with an energy-dispersive X-ray spectroscopy (SEM–EDX), Fourier-transform infrared spectroscopy (FT–IR), Raman spectroscopy, and point of zero charge. Langmuir, Freundlich, and Sips models, and a pseudo-second-order kinetic equation were used. Sips model showed the best correlation with the adsorption of CA–SCGs beads with capacities of adsorption of 91.18 mg/g for cadmium and 20.96 mg/g for nickel. CA–SCGs beads had a greater adsorption than the CA beads, achieving adsorption percentages close to 100% than alginate alone, showing their effectiveness in heavy metal removal.