Form Of Adsorption Research Articles

Lithium Recovery from Reverse Osmosis Concentrate of Geothermal Water by Spinel Type λ-MnO2 -Batch Tests

ABSTRACT Powder and granulated forms of lithium selective spinel type manganese oxide adsorbents (λ-MnO2) were evaluated for adsorption of lithium from the reverse osmosis (RO) concentrate of geothermal water. The interaction between lithium ions and λ-MnO2 adsorbents, in terms of adsorption capacity and uptake rate, was investigated by equilibrium and kinetic studies. In terms of adsorption equilibria, Langmuir isotherm adsorption model accurately represented the adsorption of lithium ions by powder and granulated λ-MnO2 adsorbents from the RO concentrate of the geothermal water. The best description of lithium uptake onto powdered and granulated adsorbents was provided by the pseudo-second-order kinetic model. Additionally, research was carried out with an objective of removing the inhibitory impacts of boron and arsenic on separation of lithium. The λ-MnO2 adsorbent showed no affinity for boron uptake from the solution. However, it exhibited some increasing uptake to arsenic with an increase in amount of the λ-MnO2 adsorbent. But it is possible to eliminate arsenic by means of arsenic selective ion exchange resins Lewatit FO36 and ArsenXnp prior to separation of lithium from the RO concentrate of geothermal water.

Guar Gum Hydrogel as a Biosorbent for Cd(II) and Cu(II) Ions: Kinetic, Equilibrium, and Thermodynamic Insights

AbstractThe effectiveness of modified guar gum (Cyamopsis tetragonoloba) as a Cd(II) and Cu(II) adsorbent in aquatic media was investigated. Synthesis of modified guar gum based on copolymerization with 2‐Acrylamido‐2‐methyl‐1‐propane sulfonic acid and acrylamide in presence of methylene bis‐acrylamide as a cross linker and in the form of hydrogel adsorbent. Various analytical techniques were employed to describe the surface morphology of the modified adsorbent. Adsorption tests were carried out under different conditions of adsorbent dose (10–50 mg), Cd(II) and Cu(II) initial concentration (25–150 mg/L), pH (1.0–7.0), temperature (∼25–55 °C), and time (∼15–120 min). The maximum uptakes (88 and 82 mg/g) were achieved at pH 6.0 and 5.0 for cadmium (II) and copper (II) ions, respectively. For both metal ions, the kinetics data for the adsorption process obeyed a pseudo second‐order rate equation (R2 = 0.9814 and 0.9845, respectively). The adsorption isotherm data were described using 3 models. Thermodynamic parameters such as enthalpy (∆H), entropy (∆S), and Gibbs free energy (∆G) changes were calculated. Cadmium and copper ions adsorption on modified guar gum was discovered to be endothermic and non‐spontaneous. For both metal ions, 5 M HCl and 1 M EDTA were utilized as de‐sorbents, with the latter having a higher desorption efficiency. The prepared hydrogel was proved as an effective promising adsorbent at capturing cadmium and copper ions from laboratory wastewaters and it could be used for further treatment of other effluent wastes.

Removal of Ciprofloxacin and Norfloxacin from Aqueous Solution with Activated Carbon from Cupuaçu (Theobroma grandiflorum) Bark.

The widespread use of antibiotics such as fluoroquinolones (FQs) has raised environmental and health concerns. This study is innovative as we investigate the removal of ciprofloxacin (CIP) and norfloxacin (NOR) from water using activated carbon derived from cupuaçu bark (CAC). This previously discarded biomass is now a low-cost raw material for the production of activated carbon, boosting the local economy. CAC was physiochemically characterized, and adsorption experiments were designed using the Box-Behnken design to assess the effects of contact time, adsorbate concentration, and adsorbent dosage on the removal efficiency and adsorption capacity. The optimal conditions were determined using the desirability function, and kinetic, isothermal, and thermodynamic experiments were performed. CAC showed a 50.22% yield, low humidity (4.81%), and low ash content (4.27%), with acidic functional groups dominating. The surface area was 1335.66 m2/g, with an average pore volume of 0.753 cm3/g and a pore diameter of 2.206 nm. Adsorption was most effective at pH 5.0 due to electrostatic interactions between the basic adsorbent and cationic forms of CIP and NOR. Optimal conditions yielded adsorption capacities of 6.02 mg/g for CIP and 5.70 mg/g for NOR, with the Langmuir model suggesting monolayer adsorption. The regeneration with NaOH was effective, but the adsorption efficiency decreased below 50% after two cycles. These findings demonstrate that CAC is a sustainable, low-cost adsorbent for treating antibiotic-contaminated water.

Reprocessible, Reusable, and Self-Healing Polymeric Adsorbent for Removing Perfluorinated Pollutants.

Here, we report a reprocessible, reusable, self-healing, and form-switching polymeric adsorbent for remediating fluorinated pollutants in water. The copolymer hydrogel is designed to contain fluorophilic segments and cationic segments to induce strong binding with perfluorinated pollutants. The sorption performance reveals rapid and quantitative removal of these pollutants, driven by the synergistic effect of fluorophilic and electrostatic interaction. Importantly, a disulfide-containing dynamic crosslinker plays a crucial role in imparting multifunctionality. This enables self-healing by the restoration of crosslinks at the cut surfaces by disulfide exchange reactions and allows for the repeated use of the adsorbent via multiple adsorption-desorption cycles. Furthermore, the adsorbent is reprocessible by cleaving the crosslinks to afford linear copolymers, which can be repolymerized into a hydrogel network on demand. Also, form-switching capability is showcased through the aqueous self-assembly of linear copolymers into a fluorinated micelle, serving as another form of adsorbent for pollutant removal.

Adsorption and removal of herbicide paraquat from aqueous solutions via novel bimetal organic framework: Kinetics, equilibrium and statistical surface modeling

Adsorption and removal of herbicide paraquat from aqueous solutions via novel bimetal organic framework: Kinetics, equilibrium and statistical surface modeling

Multi-omics inhalation toxicity assessment of urban soil dusts contaminated by multiple legacy sources of lead (Pb)

Although animal studies have evaluated lead (Pb) toxicity, they are limited to soluble forms, such as Pb-acetate, which do not reflect the range found in the exposome. Recent studies on Pb speciation of residential soils in urban areas revealed that the initial Pb sources are not persistent and are extensively repartitioned into adsorbed forms of Pb rather than insoluble phosphates. We investigated the inhalation and neurological toxicity of dusts generated from a surficial soil sample collected from a residential site with an exposomic mixture of various Pb species, both adsorbed phases (Fe and Mn oxide, humate bound Pb) and mineral phases (Pb hydroxycarbonate, pyromorphite, galena). Mice inhaled East Chicago dust (ECD) generated from a composite soil sample for 4h/day, 7 days/week, for 4 weeks. Mice were necropsied immediately, 1, 14 and 30 days post exposure to evaluate both toxicity and recovery. Exposure to ECD caused changes in memory and spatial learning in the Morris Water Maze test. RNAseq analysis of the hippocampus region revealed multiple differentially expressed genes and impacts on pathways involved in ion channel complexes, and neuron-to-neuron synapse. Metabolomics analysis of plasma highlighted significant alterations in metabolic processes immediately after exposure that resolved after 14 days of rest.

Recent Advances in Porous Bio-Polymer Composites for the Remediation of Organic Pollutants.

The increasing awareness of the importance of a clean and sustainable environment, coupled with the rapid growth of both population and technology, has instilled in people a strong inclination to address the issue of wastewater treatment. This global concern has prompted individuals to prioritize the proper management and purification of wastewater. Organic pollutants are very persistent and due to their destructive effects, it is necessary to remove them from wastewater. In the last decade, porous organic polymers (POPs) have garnered interest among researchers due to their effectiveness in removing various types of pollutants. Porous biopolymers seem to be suitable candidates among POPs. Sustainable consumption and environmental protection, as well as reducing the consumption of toxic chemicals, are the advantages of using biopolymers in the preparation of effective composites to remove pollutants. Composites containing porous biopolymers, like other POPs, can remove various pollutants through absorption, membrane filtration, or oxidative and photocatalytic effects. Although composites based on porous biopolymers shown relatively good performance in removing pollutants, their insufficient strength limits their performance. On the other hand, in comparison with other POPs, including covalent organic frameworks, they have weaker performance. Therefore, porous organic biopolymers are generally used in composites with other compounds. Therefore, it seems necessary to research the performance of these composites and investigate the reasons for using composite components. This review exhaustively investigates the recent progress in the use of composites containing porous biopolymers in the removal of organic pollutants in the form of adsorbents, membranes, catalysts, etc. Information regarding the mechanism, composite functionality, and the reasons for using each component in the construction of composites are discussed. The following provides a vision of future opportunities for the preparation of porous composites from biopolymers.

Carbon capture in polymer-based electrolytes.

Nanoparticle organic hybrid materials (NOHMs) have been proposed as excellent electrolytes for combined CO2 capture and electrochemical conversion due to their conductive nature and chemical tunability. However, CO2 capture behavior and transport properties of these electrolytes after CO2 capture have not yet been studied. Here, we use a variety of nuclear magnetic resonance (NMR) techniques to explore the carbon speciation and transport properties of branched polyethylenimine (PEI) and PEI-grafted silica nanoparticles (denoted as NOHM-I-PEI) after CO2 capture. Quantitative 13C NMR spectra collected at variable temperatures reveal that absorbed CO2 exists as carbamates (RHNCOO- or RR'NCOO-) and carbonate/bicarbonate (CO32-/HCO3-). The transport properties of PEI and NOHM-I-PEI studied using 1H pulsed-field-gradient NMR, combined with molecular dynamics simulations, demonstrate that coulombic interactions between negatively and positively charged chains dominate in PEI, while the self-diffusion in NOHM-I-PEI is dominated by silica nanoparticles. These results provide strategies for selecting adsorbed forms of carbon for electrochemical reduction.

Hydrothermally produced activated carbon spheres from discarded maize cobs for efficient removal of rose bengal dye from water environment

Hydrothermally produced activated carbon spheres from discarded maize cobs for efficient removal of rose bengal dye from water environment

Cross-Contamination of Ignitable Liquid Residues on Wildfire Debris—Detection and Characterization in Matrices Commonly Encountered at Wildfire Scenes

Ignitable liquid residue (ILR) samples play an important role in fire investigations. Similar to other types of forensic evidence, maintaining sample integrity depends on the prevention of cross-contamination during both storage and transport. This study examines cross-contamination in ILR samples on various sample matrices (gravel, soil, wood). After inducing leaks in a controlled environment, sample analysis by GC×GC-ToF MS allowed for sensitive detection and in-depth characterization of cross-contamination processes. The potential for false positive identification of ILR is notably present due to cross-contamination. Compound transmission for a mid-range ILR (gasoline), for instance, was detectable after a 1 h exposure, with a complete profile transfer occurring after 8 h regardless of the matrix type. Visual comparisons and uptake rate calculations further confirmed matrix interaction effects taking place in the form of inherent native compound interference and adsorbate–adsorbate interaction during transmission and extraction processes for soil and wood matrices. Chemometric analysis highlighted the advantage of employing statistical analysis when investigating samples under matrix interactions by identifying several statistically significant compounds for reliably differentiating cross-contamination from background and simulated positive samples in different volatility ranges and compound classes. Untargeted analysis tentatively identified three additional compounds of interest within compound classes not currently investigated in routine analysis. The resulting classification between background, contaminated, and simulated positive samples showed no potential for false positive ILR identification and improved false negative errors, as evidenced by classification confidences progressing from 88% for targeted and 93% for untargeted to 95% for a diagnostic ratio analysis of three ratios deployed in tandem.

Surface Modifications of Superparamagnetic Iron Oxide Nanoparticles with Polyvinyl Alcohol and Graphite as Methylene Blue Adsorbents

Methylene blue (MB) is one of the toxic synthetic dyes that are being discharged heavily into water supplies. Hence, MB removal is one of the most important tasks for a cleaner water supply. By using inexpensive, abundant, and easy-to-synthesize materials, superparamagnetic iron oxide nanoparticles, which were synthesized using the co-precipitation method with polyvinyl alcohol and graphite (SPION/PVA/GR), can be used to adsorb MB. The adsorbent was characterized using FE-SEM, FTIR, XRD, VSM, and BJH. The entrapment efficiency of MB on SPION/PVA/GR after 12 days was 33.96 ± 0.37–42.55 ± 0.39%, at 333.15, 310.15, and 298.15 K, and the initial concentration of MB was 0.017–0.020 mg/mL. The adsorption process can be considered spontaneous, endothermic, chemisorption, heterogeneous, or multilayer adsorption. When releasing MB at 298.15 K and a pH of 3.85 after 7 days, the release percentage ranged from 11.56 ± 0.33 to 22.93 ± 5.06 depending on the initial loading conditions and mainly the releasing temperature following the Higuchi kinetic model. Since this is a novel SPION-based MB adsorbent, optimization, and different forms of adsorbent (i.e., thin film composite) should be further researched.

The occurrence pattern of natural hydrogen in the Songliao Basin, P.R. China: Insights on natural hydrogen exploration

The occurrence pattern of natural hydrogen in the Songliao Basin, P.R. China: Insights on natural hydrogen exploration

Enhancing water resistance of α-MnO2 catalyst for efficient airborne benzene oxidation at mild temperatures via facile Ag incorporation

Enhancing water resistance of α-MnO2 catalyst for efficient airborne benzene oxidation at mild temperatures via facile Ag incorporation

Chemical Modification of Banana Peels and Banana Pseudostem for the Adsorptive Removal of Chromium (VI) from Aqueous Solution

The removal of Cr(VI) from the water was studied using raw and modified banana peels and pseudostem wastes as bio-adsorbent under the batch adsorption technique at room temperature. The chemical modification of raw adsorbents was performed by treating them with concentrated sulphuric acid. Characterizations were performed by FTIR, XRD, and SEM analyses. The raw form of adsorbents showed insignificant adsorption compared to the charred form. Therefore, the further process was carried out using modified adsorbents only. The maximum adsorption capacity for charred banana peel (CBP) and charred banana pseudostem (CBS)was found to be maximum at optimum equilibrium pH 2. The adsorption data fitted well with the Langmuir adsorption model and followed pseudo-second-order kinetics. Therefore, owing to high efficiency and low cost with maximum removal percentage, thus prepared adsorbents are expected to be used satisfactorily in the adsorption of Cr(VI) from aqueous solutions.

Exploration of haematite-loaded rice husk biochar as a low-cost nanosorbent to remove Cr (III) from the aqueous media

ABSTRACT In this study, the biochar of rice husk was modified to a nanosorbent upon loading with haematite for Cr (III) removal from aqueous solutions. Three adsorbents, rice husk, rice husk biochar and haematite-loaded rice husk biochar, were used for equilibrium adsorption studies. SEM and FTIR analysis revealed the presence of pores and various surface active sites on a nanomaterial, which were responsible for the adsorption of Cr (III). C–H, –O–H, C=O stretching vibrations were observed in characterised FTIR peaks. Modelling of adsorption isotherms indicated best fit for Freundlich isotherm with maximum Kf value of 12,218 and 39.5 for linear and non-linear nanomaterial experimental calculations, and positive n value in range of 1–10 for all forms of adsorbents, Dubinin–Radushkevich adsorption saturation capacity qs showed high readings of 9417 and 76.8 for haematite nanomaterial, Elovich isotherm favoured non-linear results in case of nanomaterial with increased Qm values 43.4–112.3 from raw form to nanosorbents and Temkin isotherm with. Kinetic and Thermodynamic results were also summarised. Constants k and h and Qe capacity were tabulated for Pseudo second order model with highest Qe in the range of 20.36–22.52 for haematite loaded biochar nanomaterial. Hence, haematite based rice husk biochar nanostructure was employed as an efficient adsorbent for uptake of chromium.

The study of NF-κB transcription factor activation by Pseudomonas aeruginosa recombinant proteins in eukaryotic cell culture.

The transcription factor NF-κB is a key factor in the activation of immune responses; it is in turn activated by pattern recognition receptors, such as TLR and NLR receptors. The search for ligands activating innate immunity receptors is an important scientific problem due to the possibility of their use as adjuvants and immunomodulators. In this study the effect of recombinant Pseudomonas aeruginosa OprF proteins and a toxoid (a deletion atoxic form of exotoxin A) on the activation of TLR4, TLR9, NOD1, and NOD2 receptors has been investigated. The study was carried out using free and co-adsorbed on Al(OH)₃ P. aeruginosa proteins and eukaryotic cells encoding these receptors and having NF-κB-dependent reporter genes. The enzymes encoded by the reported genes are able to cleave the substrate with the formation of a colored product, the concentration of which indicates the degree of receptor activation. It was found that free and adsorbed forms of the toxoid were able to activate the TLR4 surface receptor for lipopolysaccharide. OprF and the toxoid activated the intracellular NOD1 receptor, but only in the free form. This may be due to the fact that the cell lines used were not able to phagocytize aluminum hydroxide particles with protein adsorbed on them.

Novel connectivity tensor for a systematic assessment of topology and anisotropy of real membranes and microporous structures

Novel connectivity tensor for a systematic assessment of topology and anisotropy of real membranes and microporous structures

Di- and tri- cyclic aromatic hydrocarbons removal using different prepared materials based Sargassum dentifolium algae, and iron oxide

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are highly toxic and carcinogenic compounds as they are low water solubility, hardly degradable and may persist in the environment for many years. Therefore, this study was directed to PAHs ‘anthracene and naphthalene’ removal using a combination method between adsorption and degradation using sunlight. Three adsorbent materials, iron oxide (Fe) alone, Sargassum dentifolium (S) alone, and mixture of Iron oxide and Sargassum dentifolium (FeS) were prepared. Afterwards, optimisation process was performed for the three adsorbent forms through some preliminary experiments followed by full factorial design experiment to get the optimum interacted factors that achieve high PAHs removal efficiency. Some characterisation analyses such as FT-IR, TEM, DLS, zeta potential, specific surface area, magnetisation analysis, isotherm and kinetics studies were performed. The full factorial design showed that, the highest anthracene removal efficiency of 99.15% was obtained at 50 ppm concentration, 3 h contact time by using 1 g/l Sargassum dentifolium, whereas the highest naphthalene removal efficiency of 93.05% was achieved after 4 h contact time at 50 ppm concentration by using 4 g/l Sargassum dentifolium. Moreover, 93.02% naphthalene removal efficiency was stated at 50 ppm concentration after 1 h contact time by using 1 g/l mixed form of Iron oxide/Sargassum dentifolium.

An ultra-permeable hybrid Mg-MOF-74-Melamine sponge composite for fast dynamic gas separation

Shape engineering porous solids such as metal-organic frameworks (MOFs) into hierarchical structured adsorbents allows significant process intensification. Here we propose a facile approach to obtain a mouldable structured adsorbent with high loading of porous solids by employing a commercially available low-cost melamine sponge. As a case study, Mg-MOF-74 was synthesized in an aqueous media at room temperature and coated successfully over the melamine sponge, without any pre-treatment/additive, to yield a melamine sponge-based Mg-MOF-74 composite (Mg-MOF-74@MS). Even after multiple coating steps, the composite displayed remarkable compressibility, thus providing additional degrees of freedom in designing packed bed systems over other rigid adsorbent forms and structures. The dynamic gas separation capability of the prepared Mg-MOF-74@MS composite was demonstrated via breakthrough experiments with mixtures of 20% CO 2 and 80% CH 4 at 1 bar and 298 K. Owing to the spatial structure of melamine sponge, the composite retained the adsorption properties of Mg-MOF-74 for CO 2 capture i.e., high dynamic capacity (5.07 mmol/g), high selectivity (>100), facile regeneration and performed better than binderless Mg-MOF-74 pellets in terms of mass transfer, unused bed length (LUB) and pressure drop (large permeability). Overall, these findings open an interesting field of research with melamine sponge-based MOF structured adsorbent as a potential candidate for gas-phase adsorption-based separation applications. • An additive free route to obtain compressible structured adsorbent is presented. • The Mg-MOF-74@MS composite showed high MOF loading and thermomechanical stability. • Mg-MOF-74 adsorption properties were retained in the Mg-MOF-74@MS composite. • It showed higher specific productivity in contrast to traditional shaped adsorbent.

A comprehensive review on the synthesis techniques of porous materials for gas separation and catalysis

AbstractIntrinsic structural characteristics of porous materials have found significant applications in selective separation of gases and heterogeneous catalysis. While using porous materials for gas separation and catalysis, some of the challenging issues are the strength of catalytic sites, hydrothermal stability, crystalline order of solids, and selectivity. Researchers' ability to engineer the synthesis strategies rationally can help overcome technological challenges. In recent years, breakthroughs in porous materials are focused on developing different chemistries to control the pore architecture. This review focuses on recent advances made in synthesis strategies of porous materials and their impact on gas separation and catalysis applications. A significant part of this review is devoted to various synthesis methods, such as various types of templating methods, molecular layer deposition, sol–gel technique, and polymerization methods. Improvement in various catalytic reactions and gas separations due to different functionalization methods is also summarized. Lastly, we have discussed the applications of porous materials in the form of adsorbents and membranes in commercial processes. We hope that this review will serve as a quick reference for beginners who want to synthesize porous materials with control of pore structure.