Sorption Experiments Research Articles

Moisture adsorption and tensile strength of pectin-pineapple juice films at different relative humidities

This study evaluated the effect of different relative humidities (RH) (23%, 55%, and 75%) during storage on the stability against moisture adsorption and the strength of pectin-pineapple juice (P-PJ) films. The pectin-based films were added with various loading of pineapple juice (PJ). The static gravimetric technique determined the equilibrium moisture content (Me). Different storage relative humidities (RH) ranging from 11% to 90% were achieved using saturated salt solutions. The weight increase of PPJ films was measured for 7 to 14 days until equilibrium was established. The tensile strength was tested using a texture analyzer. The results showed that the different storage conditions significantly affected the film’s tensile strength. The film with 2 g PJ at 23% RH had the highest moisture adsorption and tensile strength (52.91±3.08 MPa) compared to other film formulations. The moisture adsorption isotherms of Peleg, GAB, and BET models were compared for their ability to best describe the experimental moisture sorption data with the highest goodness of fit (coefficient of determination, R2 ). The Peleg model was the most suitable data to fit the experimental data with the highest R2 of 0.9. The moisture sorption properties of the P-PJ films are important information to understand the changes in the films’ stability and strength due to the extent of exposure to relative humidity during storage.

Exploring the efficacy of low-cost biosorbent for the effective removal of the toxic azo dye “bemacid red” from aqueous solution: a comprehensive study

Recently, developing low-cost biosorbents for dye-loaded wastewater remediation has become an important area of research. This study examined the potential of Casuarina Equisetifolia pines (CEP) as a green biosorbent for the sorption of an anionic textile dye Bemacid red (BR) from an aqueous solution. The effect of various factors including the initial dye concentration, solution pH, contact time, particle size, agitation speed, ionic strength, biosorbent dosage, and temperature was investigated. The biosorbent was characterized using FTIR, SEM, XRD, TGA, and pHpzc. The experimental results show that the sorption was pH-dependent with a high sorption capacity of BR removal in the acidic range. It has been observed that the removal of BR increases with time until equilibrium is reached after 30 min. The removal is fast and efficient; it yielded around 90% removal efficiency in an acidic medium. The BR sorption efficiency increased with an increase in CEN dosage, initial dye concentration, and ionic strength, but decreased with increasing in temperature, biosorbent particle size, and agitation speed. Experimental sorption data were modeled by different theoretical equilibrium isotherms such as Langmuir, Freundlich, Temkin, and D-R. The sorption process fitted well to the Langmuir model, with a maximum monolayer sorption capacity of 27.62 ± 1.3 mg/g. Thermodynamic studies showed that the sorption system was spontaneous and exothermic, the pseudo-second-order kinetic model revealed excellent linearity and highlighted the method’s robustness. Accordingly; the CEP is a very efficient and low-cost biosorbent and a promising alternative for eliminating dyes from industrial wastewater.

Microplastics and organic contaminants: Investigation of the sorption process on different polymer types.

Microplastics and organic contaminants: Investigation of the sorption process on different polymer types.

Impact of cementitious leachate on sorption of various iodine species to sediments.

Impact of cementitious leachate on sorption of various iodine species to sediments.

Biochar MMT ZnAl LDH composite materials derived from solid waste for heavy metal removal in artificial acid mine drainage

This study investigates the synthesis and performance of a biochar-based composite, integrating montmorillonite (MMT) and ZnAl layered double hydroxide (LDH), for the removal of Fe and Mn from acid mine drainage. The biochar_MMT_ZnAl LDH composite, synthesized from solid waste materials, was characterized using BET, XRD, FTIR, TGA, and SEM-EDS analyses. The material demonstrated a surface area of 117.54 m2/g and a pore volume of 0.21 cm3/g, significantly surpassing non-composite biochar with a surface area of 14.81 m2/g. The batch sorption experiment showed rapid adsorption kinetics, achieving 99% Mn removal within 7 min at 0.5 g adsorbent dosage, reducing Mn concentration from 100 mg/L to 0.07 mg/L. For Fe, an 87% reduction was achieved after 400 min using 0.5 g of plain biochar, while biochar_MMT_ZnAl LDH showed superior adsorption performance with a final Fe concentration below 0.07 mg/L. Adsorption isotherm analysis indicated that biochar followed the Dubinin–Radushkevich model, while the composites adhered to the Redlich–Peterson model. Kinetic studies revealed a strong fit with the Pseudo-Second-Order model (R2 = 1 for biochar_MMT), suggesting chemisorption as the dominant mechanism. Thermodynamic analysis confirmed the spontaneity and endothermic nature of the adsorption process, with ΔG values ranging from − 18,758 to − 92,932 J/mol for Fe and Mn removal. The findings highlight the potential of biochar-based composites in developing cost-effective and environmentally sustainable solutions for acid mine drainage treatment.

Insights into the Structural Transformation of Amorphous ZrP, α-ZrP, and γ-ZrP: Sr2+ Sorption Behavior and Mechanism.

This study investigates the synthesis and Sr2+ sorption properties of three different crystal types of zirconium phosphate (ZrP)─amorphous ZrP (am-ZrP), α-ZrP, and γ-ZrP─prepared via a one-pot reflux method. The materials were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG), solid-state 31P magic angle spinning nuclear magnetic resonance (NMR) spectroscopy, and sodium hydroxide titration. Sorption experiments revealed that Sr2+ uptake by all three ZrPs increased with pH. Sorption isotherms were evaluated across a range of Sr2+ concentrations, with maximum sorption capacities at pH 9 of 2.48 mmol g-1 for am-ZrP, 2.71 mmol g-1 for α-ZrP, and 2.04 mmol g-1 for γ-ZrP. Sorption kinetics and the influence of competing ions on Sr2+ uptake were also examined. Notably, all three ZrP materials demonstrated excellent reusability in sorption-desorption cycles. Finally, the structural transformation and Sr2+ sorption mechanism were elucidated through 31P NMR, XPS, FTIR and TEM analyses.

Sorption behavior of 137Cs and 60Co onto raw and cellulose-modified Greek bentonite.

Sorption behavior of 137Cs and 60Co onto raw and cellulose-modified Greek bentonite.

Sorption experiments using stemflow: Reproduction and understanding of radiocesium dynamics on the forest floor during the early stage after the Fukushima nuclear accident.

Sorption experiments using stemflow: Reproduction and understanding of radiocesium dynamics on the forest floor during the early stage after the Fukushima nuclear accident.

Sorption of Sulfonamide Antibiotics in Peat Soils With Different Properties

ABSTRACTBackgroundSulfonamide antibiotics have been discovered as emerging pharmaceutical pollutants worldwide and are only poorly removed in wastewater treatment. At the landscape level, peat soils are significant water collectors and, thus, are sinks for organic pollutants. However, the fate of pharmaceutically active contaminants in peat soil is, as yet, largely unclear.AimFactors regulating sorption as a dominant process that influences the filtering and buffering of the sulfonamides sulfadiazine (SDZ) and sulfamethoxazole (SMX) in different peat soils were investigated.MethodsThe sorption of SDZ and SMX was investigated in batch sorption experiments using peat soils with different physicochemical properties and under different land use, including sustainable wet peatland cultivation (paludiculture).ResultsSorption Kd values ranged from 21.39 to 102.8 mL g−1 for SDZ and 11.23 to 107.3 mL g−1 for SMX. Soil pH, organic carbon content, and C/N ratios were significantly correlated to sorption of the sulfonamides. Non‐linear regression analyses showed that the Freundlich isotherm model was generally best suited to describe sorption of both sulfonamides (0.54 ≤ R ≤ 0.98). Freundlich n values were generally different from 1 for both sulfonamides, indicating co‐mechanistic sorption as opposed to partitioning alone. A quantitative structure–property relationship (QSPR) constructed to predict sorption Kd values showed a good cross‐validated performance (R2adj = 0.79, root mean squared error [RMSE] = 8.71).ConclusionsThe sorptive capacities of peat soils for SDZ and SMX antibiotics are higher than those of many terrestrial soils. The quantity and stoichiometric properties of the organic matter fraction, as well as the pH conditions, significantly affect the ability of the soils to immobilize these antibiotics.

Cross-linked carboxymethyl cellulose biosorbent for zinc removal: a sustainable remediation of heavy metal-polluted waters

This study focuses on the preparation and characterization of cross-linked carboxymethyl cellulose (CMC) biosorbent for efficient removal of Zn2⁺ ions from aqueous solutions. The microstructural features of the biosorbent were examined using scanning electron microscopy (SEM), while elemental analysis was conducted using an elemental analyzer to determine carbon (C), hydrogen (H), nitrogen (N), and sulfur (S) content. Fourier transform infrared (FTIR) spectroscopy was employed to identify functional groups within the biosorbent. Sorption experiments revealed that increasing the biosorbent dose led to higher Zn2⁺ removal rates until equilibrium was reached. The optimal pH for Zn2⁺ removal was determined to be ≥ 5, attributed to the conversion of acetate group to its ionic form. Rapid kinetics were observed, with 99% removal achieved within 5 min. The biosorbent exhibited a maximum sorption capacity of 10.809 mg/g and a removal rate of 99% at pH 5. Desorption studies demonstrated efficient Zn2⁺ recovery using 0.25 M HCl solution, with a total desorption rate exceeding 99%. The findings indicate the potential for cost-effective regeneration of the biosorbent using dilute acid solutions, enhancing its sustainability and practical applicability in water purification processes. Additionally, the biosorbent’s selectivity for Zn2⁺ ions over competing ions and its effectiveness in treating real water samples, including those containing Na⁺, K⁺, Ca2⁺, and Mg2⁺, highlight its suitability for practical water purification applications.

Separation of La(III) and Ni(II) from Binary System Using Manganese Oxide Nanorods

Abstract The recovery and separation of lanthanum from a La(III)/Ni(II) mixture present a significant challenge in obtaining high-purity lanthanum, which is necessary for many applications in various industries. In the present study, manganese oxide nanorods were prepared and characterized by TEM, EDX, SEM, FT-IR, TGA, and XRD. The TEM images reported that the manganese oxide nanoparticles were arranged into rod-shaped structures with pores between them. Batch adsorption experiments were performed to evaluate the sorption efficiency and separation of La(III) and Ni(II) from the binary system under varying conditions, including shaking time, solution pH, initial metal ion concentration, adsorbent dosage, and temperature. The results obtained showed that the sorption process of La(III) and Ni(II) using MnO2-nanorods fit well with the pseudo-second-order kinetics and the Langmuir isotherm model. The experimental sorption capacities according to the Langmuir isotherm model were found to be 13.757 mg/g and 0.766 mg/g for La(III) and Ni(II), respectively. According to thermodynamic results, the sorption process for Ni(II) and La(III) was endothermic and spontaneous was verified by the positive ΔHo and the negative ΔGo values. Furthermore, the MnO2-nanorods presented excellent selectivity and separation of lanthanum from the La(III)/Ni(II) mixture at pH 3.0, shaking time 30.0 min, and 0.05 adsorbent dosage at room temperature.

From soil sorption to bioaccumulation: Tracing the endectocide ivermectin in soil and earthworms.

From soil sorption to bioaccumulation: Tracing the endectocide ivermectin in soil and earthworms.

Insight into sequestration and release characteristics of uranium(VI) on phlogopite in the presence of humic acid.

Insight into sequestration and release characteristics of uranium(VI) on phlogopite in the presence of humic acid.

Towards a better understanding of sorption of persistent and mobile contaminants to activated carbon: Applying data analysis techniques with experimental datasets of limited size.

Towards a better understanding of sorption of persistent and mobile contaminants to activated carbon: Applying data analysis techniques with experimental datasets of limited size.

INVESTIGATION OF TIN-LITHIUM ALLOY BEHAVIOR IN HIGH-TEMPERATURE HYDROGEN ISOTOPE ENVIRONMENTS: SORPTION AND DESORPTION ANALYSIS

Nuclear fusion's effectiveness relies heavily on managing the intense power loads that strike the first wall, especially the divertor in plasma-physical devices. Due to their self-regulating liquid surfaces, liquid metals, such as lithium and tin, present a promising alternative to solid plasma-facing materials. A promising candidate is a tin-lithium alloy, which is expected to combine the beneficial properties of its constituent metals. The present study investigates tin-lithium alloy's sorption and desorption characteristics when exposed to hydrogen isotopes under high-thermal stress conditions. Specifically, experiments were conducted using a Sn73Li27 alloy with adsorption and thermally stimulated desorption (TDS) techniques employed to characterize its behavior. The sorption experiments were performed under high-temperature conditions from 450°C to 600°C and at different values of residual deuterium pressure in the device volume. The TDS experiments involved measuring the gas flows released from the tin-lithium alloy into the evacuated chamber under linear heating conditions. The temperature dependence of the effective deuterium solubility constant in the alloy was calculated, revealing the complexity of the interaction mechanisms influenced by experimental conditions. The results provide insights into the interaction dynamics between the tin-lithium alloy and hydrogen isotopes, underlining the material’s performance and stability in high-temperature environments.

Adsorption of crystal violet on polystyrene microplastics in aqueous: optimization, modeling, and assessment of isotherms and kinetics

The global increase in plastic production has significantly contributed to the contamination of aquatic environments with MPs. This study examined the adsorption of CV dye onto PS MPs in aquatic ecosystems. BBD was utilized to optimize adsorption conditions and evaluate the effects of key independent variables on the adsorption process. The sorption experiments were conducted using reaction mixtures containing PS at levels ranging from 0.1 to 1.5 g/L and CV at concentrations of 5 to 20 mg/L. The pH levels of the samples were adjusted to range from 4 to 10, while the duration of interaction varied between 10 and 60 min. The findings revealed that the optimal sorption rate for CV (84.96%) was achieved at a CV level of 12.5 mg/L, a PS dosage of 1 g/L, a pH level of 7, and an interaction duration of 35 min. In this investigation, the ZP of PS particles transitioned from − 45.6 to − 16.8 mV following the sorption of CV. Furthermore, the kinetics of CV sorption were most accurately described by the pseudo-first-order model, demonstrating a high R2 value of 0.99. The Langmuir isotherm (R2 = 0.99) further confirmed the presence of significant interactions between the dye molecules and the surface of the sorbent, with the highest sorption capacity quantified at 6.25 mg/g. This study highlights the role of PS microplastics as carriers of harmful dyes, such as CV, in aquatic environments. It underscores the urgent need for further research into the environmental consequences of microplastic pollution and the development of strategies to mitigate their impact.

Polyethylene fragments in Argentinean horticultural soils: Environmental transformation to a composite material.

Polyethylene fragments in Argentinean horticultural soils: Environmental transformation to a composite material.

Effective treatment of thioantimonates-bearing waters by nanocrystalline iowaite, an iron-based layered double hydroxide.

Effective treatment of thioantimonates-bearing waters by nanocrystalline iowaite, an iron-based layered double hydroxide.

Ideal Molecular Sieving with a Dense MOF for Helium Upgrading with Highly Diffusion Selective Mixed Matrix Membranes

AbstractHelium is one of the most critical resources of this planet, as it is a finite resource, cannot be produced from radioactive decay and escapes the atmosphere, while being extraordinarily important for high‐tech applications in research and medicine. A concept of using the “dense” metal–organic framework (MOF) MIL‐116(Ga) as a molecular sieve specifically allowing diffusion of He is demonstrated. Incorporating up to 20 wt.% MIL‐116(Ga) into polysulfone, a chemically stable, mechanically robust, and commercially available polymer, high‐performance mixed matrix membranes are fabricated and tested in gas permeation. The membranes reach He permeabilities up to 37.4. Barrer and He/CH4 selectivity of 1190, mimicking He concentration of 4% of a natural gas reservoir. With increasing filler content, the permeability of He increases, while CH4 permeability decreases. Microstructural analysis of the MIL‐116(Ga) reveals that the crystals grew into druse‐like hollow crystals, highly beneficial for fast He permeability. CH4, N2, and CO2 cannot enter the crystal, as proven by sorption experiments, providing high diffusional selectivity. Furthermore, polymer filler interactions are investigated by scanning electron microscopy and energy dispersive X‐ray spectroscopy demonstrating ideal compatibility. The performance is benchmarked to existing composite materials and polymers, where MIL‐116(Ga)‐formate stands out with extraordinary membrane performance.

Amine‐Functionalized Triazolate‐Based Metal–Organic Frameworks for Enhanced Diluted CO2 Capture Performance

AbstractEfficient CO2 capture at concentrations between 400–2000 ppm is essential for maintaining air quality in a habitable environment and advancing carbon capture technologies. This study introduces NICS‐24 (National Institute of Chemistry Structures No. 24), a Zn‐oxalate 3,5‐diamino‐1,2,4‐triazolate framework with two distinct square‐shaped channels, designed to enhance CO2 capture at indoor‐relevant concentrations. NICS‐24 exhibits a CO2 uptake of 0.7 mmol/g at 2 mbar and 25 °C, significantly outperforming the compositionally related Zn‐oxalate 1,2,4‐triazolate – CALF‐20 (0.17 mmol/g). Improved performance is attributed to amino‐functions that enhance CO2 binding and enable superior selectivity over N2 and O2, achieving 8‐fold and 30‐fold improvements, respectively, in simulated CO2/N2 and CO2/O2 atmospheric ratios. In humid environments, NICS‐24 retained structural integrity but exhibited an 85 % reduction in CO2 capacity due to competitive water adsorption. Breakthrough sorption experiments, atomistic NMR analysis, and DFT calculations revealed that water preferentially adsorbs over CO2 due to strong hydrogen‐bonding interactions within the framework. Gained understanding of the interaction between CO2 and H2O within the MOF framework could guide the modification via rational design with improved performance under real‐world conditions.