Adsorption Of Organic Pollutants Research Articles

Chemical and Thermal Changes in Mg3Si2O5 (OH)4 Polymorph Minerals and Importance as an Industrial Material

Serpentine (Mg3Si2O5(OH)4), like quartz, dolomite and magnesite minerals, is a versatile mineral group characterized by silica and magnesium silicate contents with multiple polymorphic phases. Among the phases composed of antigorite, lizardite, and chrysotile, lizardite and chrysotile are the most prevalent phases in the serpentinites studied here. The formation process of serpentinites, which arise from the hydrothermal alteration of peridotites, influences the ratio of light rare earth elements (LREE) to heavy rare earth elements (HREE). In serpentinites, the ratio of light rare earth elements (LREE)/heavy rare earth elements (HREE) provides insights into formation conditions, geochemical evolution, and magmatic processes. The depletion of REE compositions in serpentinites indicates high melting extraction for fore-arc/mantle wedge serpentinites. The studied serpentinites show a depletion in REE concentrations compared to chondrite values, with HREE exhibiting a lesser degree of depletion compared to LREE. The high ΣLREE/ΣHREE ratios of the samples are between 0.16 and 4 ppm. While Ce shows a strong negative anomaly (0.1–12), Eu shows a weak positive anomaly (0.1–0.3). This indicates that fluid interacts significantly with rock during serpentinization, and highly incompatible elements (HIEs) gradually become involved in the serpentinization process. While high REE concentrations indicate mantle wedge serpentinites, REE levels are lower in mid-ocean ridge serpentinites. The enrichment of LREE in the analyzed samples reflects melt/rock interaction with depleted mantle and is consistent with rock–water interaction during serpentinization. The gradual increase in highly incompatible elements (HIEs) suggests that they result from fluid integration into the system and a subduction process. The large differential thermal analysis (DTA) peak at 810–830 °C is an important sign of dehydration, transformation reactions and thermal decomposition, and is compatible with H2O phyllosilicates in the mineral structure losing water at this temperature. In SEM images, chrysotile, which has a fibrous structure, and lizardite, which has a flat appearance, transform into talc as a result of dehydration with increasing temperature. Therefore, the sudden temperature drop observed in DTA graphs is an indicator of crystal form transformation and CO2 loss. In this study, the mineralogical and structural properties and the formation of serpentinites were examined for the first time using thermo-gravimetric analysis methods. In addition, the mineralogical and physical properties of serpentinites can be recommended for industrial use as additives in polymers or in the adsorption of organic pollutants. As a result, the high refractory nature of examined serpentine suggests that it is well-suited for applications involving high temperatures. This includes industries such as metallurgy and steel production, glass manufacturing, ceramic production, and the chemical industry.

Deciphering the role of nonylphenol adsorption in soil by microplastics with different polarities and ageing processes.

In the soil environment, microplastics (MPs) commonly coexist with organic pollutants such as nonylphenol (NP), affecting the migration of NP through adsorption/desorption. However, few studies have focused on the interaction between NP and MPs in soil, especially for MPs of different types and ageing characteristics. In this study, non-polar polypropylene (PP) and polar polyamide (PA) MPs were aged either photochemically (144 h) or within soil (60 days), then used to determine the effect of 5 % MPs on the adsorption behaviour of NP (0.1-4.0 mg/L) in soil. Results showed that both ageing processes significantly promoted the conversion of -CH3 groups to C-O and CO on the surface of PPMPs, while PAMPs exhibited amide groups changes and a reduction in average particle size due to ageing. Additionally, both ageing processes promoted the adsorption of NP by soil containing PPMPs, due to an increase in oxygen-containing functional groups and specific surface area. In contrast, the NP adsorption capacity of soil containing PAMPs decreased by 15.4 % following photochemical ageing due to hydrolysis of amide groups, but increased by 21.15 % after soil ageing due to reorganization of amide groups, respectively. The soil-PAMPs systems exhibited a stronger affinity for NP compared to the soil-PPMPs systems, which was primarily attributed to the dominant role of hydrogen bonding. NP was found to be distributed mainly on soil particles in the soil-PPMPs systems, while it tended to be adsorbed by MPs in the soil-PAMPs systems, especially in the soil aged MPs system. This study provides a comprehensive analysis of the complex effects of MPs on coexisting pollutants in soil environments, highlighting the effect of MP characteristics on the adsorption of organic pollutants, which is essential for understanding the transport behaviour of organic pollutants.

Enhancing AI model robustness in organic pollutant adsorption forecasting: Insights from feature analysis

Despite the significant increase in the use of artificial intelligence (AI) models in adsorption, there is still a lack of comprehension on how the input variables can affect the outputs of each model. In this study, we employed data provided by the standard removal of two organic pollutants by pyrolyzed soybean hulls to demonstrate how analyzing the correlation between features is essential. The experiments were conducted at 298 K and pH 6, generating 270 experimental points. The features to be used as input variables for the models were chosen after a correlation analysis that excluded highly correlated ones. The models, Gradient Boosting (GB), Artificial Neural Networks (ANN), and Adaptive Neuro-Fuzzy Inference System (ANFIS) were evaluated to determine the best performance in prediction and generalization. All models showed good statistical performance, with R2 0.9906 – 0.9991, MSE 0.0666 – 0.0099, and MAPE 4.7927 – 0.6939 %. As the complexity of the model increased, its performance improved, and ANFIS was the model that best predicted the data. The analysis of the feature importance showed that time and initial concentration are the essential variables. Thus, this study provides how the input information can alter the prediction and surpass the capabilities of models fed with indiscriminate data, highlighting the importance of carefully selecting parameters to ensure that even the simplest model can be robust and reproducible.

Post-synthetic sulfonation of resorcinarene-based porous organic polymer for superfast adsorption of diverse organic pollutants

A resorcinarene-based porous organic polymer was synthesized via the Suzuki–Miyaura coupling reaction and then functionalized by chlorosulfonic acid to obtain a sulfonated product named BaPy-SO3H. Characterization results indicate that BaPy-SO3H has porous skeletons, excellent thermal stability, and electronegative surface charges. Remarkably, BaPy-SO3H exhibits superfast rates and reaches adsorption equilibrium within 1 min towards diverse organic pollutants including dyes, herbicides, and antibiotics via electrostatic interactions, π–π interactions, and host–guest effects. Especially for Crystal Violet, Malachite Green, and Paraquat, BaPy-SO3H achieves apparent rate constants for a pseudo-second-order model of 31.24, 31.27, and 30.63 g mg−1 min−1, respectively, which are the highest values among reported adsorbents to the best of our knowledge. Meanwhile, the maximum adsorption capacity of BaPy-SO3H reaches 1850 mg g−1 for Rhodamine B, 2295 mg g−1 for Methyl Blue, 1503 mg g−1 for Crystal Violet, and 1304 mg g−1 for trimethoprim, surpassing most of the adsorbents reported so far. The above results demonstrate the superior adsorption performance of BaPy-SO3H towards diverse organic pollutants and its potential applications in real-water scenarios.

Piezoelectric photocatalytic degradation of formaldehyde based on BFO@OCN heterojunctions

Piezoelectric photocatalysts represent a new class of environment-cleaning materials containing a self-electricity nanogenerator. Wind is one of the common energy sources in the natural environment. The piezoelectric field generated by the action of wind on piezoelectric materials can promote the adsorption of organic pollutants and also facilitate the transfer and separation of photogenerated carriers, thereby improving the efficiency of photocatalytic degradation of formaldehyde. This work developed a BFO@OCN heterojunction composite combing BiFeO3 nanocubes (BFO) and g-C3N4 nanosheets with oxygen vacancies (OCN). This piezoelectric photocatalyst exhibited high activity in degradation of formaldehyde in gas under light irradiation. Within 90 min, the formaldehyde concentration reduced from 1.50 ppm to 0.68 ppm, almost 2 times higher than the pure CN. This enhanced catalytic performance can be attributed to the synergistic interplay between the wind-induced piezoelectric field generated by BFO nanocubes in wind and the heterojunction with oxygen vacancies from g-C3N4 nanosheets. The piezoelectric field promoted the transfer of photoelectrons and holes in opposite directions, which could inhibit their recombination. Meanwhile, it also induced the generation of oxygen vacancies from g-C3N4 nanosheets. Our research findings provided a feasible strategy for developing high-efficiency piezoelectric photocatalysts, which could be decorated on the car outer-surface for self-cleaning and air purification under sunlight irradiation.

Insight into the molecular mechanism of organic pollutants’ adsorption on magnetic ZIF-8 synthesized via a transformational route

This study presents the synthesis of Fe3O4@Zeolite Imidazolate Framework-8 (Fe3O4@ZIF-8), a novel magnetic core–shell adsorbent engineered for enhance adsorption of organic pollutants. The process begins with the formation of spherical magnetite aggregates (i.e., Fe3O4) via a solvothermal method, using polyacrylic acid for stabilization and capping. A ZIF-8 shell is then grown through a sol gel process followed by reaction with 2-methylimidazole, resulting in a crystalline shell approximately 60 nm thick. Characterization techniques, including energy dispersive X-ray analysis and X-ray diffraction, confirm the successful preparation of Fe3O4@ZIF-8. The adsorption capabilities were evaluated using methylene blue (MB) and diclofenac sodium (DCF) as model pollutants. Fe3O4@ZIF-8 demonstrated rapid removal efficiencies, with 98 % removal of MB (6.01 × 10-4 mg·g−1·min−1) and DCF (4.43 × 10-4 g·mg−1.min−1) within 15 and 30 min, respectively, significantly outperforming conventional activated carbon. Thermodynamic studies indicate that the adsorption processes are spontaneous; enthalpic changes drive MB adsorption, while DCF is influenced by entropic factors. Molecular modeling reveals preferential adsorption behaviors on different ZIF-8 facets, with stronger interactions for MB due to π-π stacking and hydrogen bonding. These findings underscore the potential of Fe3O4@ZIF-8 as an effective adsorbent for water purification, highlighting its substantial adsorption capacity (73.2 mg·g−1 for MB and 53.8 mg·g−1 for DCF), stability, and reusability.

Influence of micro- and nano-plastics on phenanthrene adsorption at the root-water interface

The adsorption of organic pollutants onto plant root surfaces is an initial crucial stage in the transfer of these pollutants from aqueous or soil solutions to plant systems. This study explored the potential influence of micro- and nano-plastics (MNPs) (0.1–100 μm) on the process of phenanthrene (Phe) adsorption at the root–water interface. The findings indicate that MNPs can exhibit either promotional or inhibitory effects on the root adsorption of organic pollutants, depending on both their particle size and content. Specifically, both the sorption capability of MNPs for Phe and their tendency to accumulate on or within root tissues increase with decreasing particle size. These dual effects facilitate the accumulation of nanoscale MNPs (0.1–6 μm in this work) within roots, which function as efficient carriers for Phe and increase Phe accumulation in root tissues. In contrast, MNPs with larger particle sizes (1–100 μm in this work) exhibit reduced affinity for roots and are more prone to remain in solution, thereby exerting more pronounced competitive inhibition against the adsorption of Phe by roots. However, when the concentration of nano-plastics in the rootwater system exceeded the retention capacity of the roots, the excess nano-plastics could compete with the roots for Phe, potentially reducing overall Phe sorption by the roots. These conditional effects of MNPs as either competitors or facilitators (vectors) in the root adsorption processes of organic pollutants may account for the different roles observed in previous studies where MNPs exhibited varying effects on the plant accumulation of organic pollutants.

Bio-sourced multifunctional adsorbent of chitosan and adipic acid activated-dragon fruit peels for organic dye removal from water: Eco-friendly management and valorization of biomass

Employing sustainable biomaterials obtained from waste biomass and biopolymers provides a very promising method for eliminating organic dyes from wastewater. This study presents a novel adsorbent of modified dragon fruit peels and chitosan, addressing wastewater treatment and environmental waste management. Precisely, a bio-sourced multifunctional (high level of functional groups) adsorbent (hereinafter, CHS/DFP-ADP) was developed from chitosan and adipic acid activated-dragon fruit (Hylocereus polyrhizus) peels. This biomaterial was applied to effectively adsorb organic pollutants (safranin O dye, SAF-O) from water. The adsorption variables, namely A: CHS/DFP-ADP dosage (0.02–0.08 g), B: pH (4–10), and C: duration (10–40 min), were modeled and optimized using the Box-Behnken Design (BBD). The results of the BBD model showed the optimum adsorption parameters for achieving the highest level of SAF-O removal (94.83 %) were as follows: CHS/DFP-ADP does = 0.049 g, the pH ∼ 10, and the contact duration = 40 min. The experimental results on the dye adsorption by CHS/DFP-ADP demonstrated conformity with the pseudo-first-order and Freundlich models. The biomaterial demonstrated a significant capability to adsorb SAF-O dye, with an adsorption capacity of 607.2 mg/g. The adsorption process of the cationic dye on the CHS/DFP-ADP involves several interactions, such as Yoshida H-bonding, electrostatic forces, n-π, and H-bonding. This work aligns with the principles of green chemistry and sustainable development, offering an innovative approach to tackle environmental concerns and promote the circular economy. The present effort meets several Sustainable Development Goals (SDGs), such as SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Consumption and Production), SDG 13 (Climate Action), and SDG 14 (Life Below Water).

BiOCl-PVDF nanofibrous membrane for synergic oil-water separation and degradation of dye

Polymeric membranes have garnered remarkable attention, attributed to the significant breakthrough in the filtration of oily wastewater. However, the major setbacks of pristine polymeric membranes include susceptibility to fouling and chemical instability. Addressing such issues, this work focusses in the modification of polymer membranes using a metal oxyhalide, such as Bismuth oxychloride (BiOCl). This modification not only enhances water purification capabilities but also strengthens the membrane, protecting it from environmental deterioration and extending its lifespan. BiOCl was integrated into an electrospun pristine nanofibrous polymeric membrane using hydrothermal technique. The synthesized membrane matrix displayed superhydrophilicity and underwater superoleophobicity, effectively separating oil-in-water mixtures and emulsions. Moreover, BiOCl was effectively utilized to assess organic pollutant adsorption and degradation through photocatalysis. In addition, the membrane exhibited exceptional recyclability and withstood harsh conditions, contributing to its mechanical stability. The numerous advantages, enhance the effectiveness of BiOCl modified membrane in water pollution remediation.

Hyper-Cross-Linked Polyindole for Selective Adsorption and Resource Utilization of Organic Pollutants in Water.

Efficient treatment and utilization of organic pollutants in water are difficult for environmental remediation. A new hyper-cross-linked polymer (PIn-HCP) with high specific surface area was constructed via polyindole (PIn) as building blocks. Rich pore structures and abundant adsorption sites in PIn-HCP were obtained by hyper-cross-linking. The specific surface area of PIn-HCP was enhanced from 14.85 to 431.89 m2/g. The adsorption capacities of PIn-HCP-2 for methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and tetracycline hydrochloride (TH) are 902.0, 275.2, 16.0, and 0.0 mg/g, respectively. PIn-HCP also realized selective adsorption of MB, which can better separate MB/RhB and MB/TH. MB is adsorbed onto PIn-HCP via a synergistic mechanism including π-π stacking, electrostatic interaction, cation-π interaction, hydrogen bonding interaction, and ion exchange. The huge conjugated structure of PIn promotes PIn-HCP to selectively adsorb MB. In addition, PIn-HCP also retains the electrochemical properties of PIn. MB can improve the specific capacitance of PIn-HCP up to five times, and it has potential as a supercapacitor electrode. PIn-HCP offers a promising and practical solution for the efficient treatment and utilization of organic pollutants in water.

Adsorption and desorption of phenanthrene and 1-hydroxyphenanthrene by goethite-coated polyvinyl chloride

Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments, and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics. In this study, three kinds of composites with different coverage were prepared by coating goethite on the surface of polyvinyl chloride microplastics to investigate the adsorption and desorption behavior of phenanthrene (PHE) and 1-hydroxyphenanthrene (1-OHPHE), and the effect of mucin on desorption was investigated. The results showed that goethite promoted the adsorption of PHE and 1-OHPHE by increasing the specific surface area of the composites. With the increase of the cover degree, the adsorption of PHE decreased because of the decrease in hydrophobicity; while the adsorption of 1-OHPHE initially increased and then decreased with the contributions of hydrophobic interaction and hydrogen bond. The adsorption of 1-OHPHE could be influenced by the pH and ionic strength primarily through electrostatic interactions and Ca2+ bridging. The goethite significantly increased the desorption hysteresis for two chemicals due to the complicated pore structures and increased adsorption affinity. Mucin promoted the desorption of PHE through competitive adsorption, and inhibit the desorption of 1-OHPHE through hydrophobic interaction, hydrogen bonding and Ca2+ bridging. This study elucidated the effects of natural minerals on the adsorption and desorption behavior of organic pollutants on microplastics, briefly discussed the effects of organic macromolecules on the desorption behavior of pollutants with different properties, and emphasized the different environmental behaviors of pollutants.

Ti3C2TX MXene/loofah-derived carbon aerogel for high-efficiency adsorption of organic pollutants in wastewater

The contamination of wastewater by organic pollutants significantly impacts human health and the environment due to their carcinogenic nature and various adverse effects. To address this issue, this study offers a high-efficiency and low-cost biomass-based carbon aerogel adsorbent, which was prepared through the hydrothermal carbonization of loofah, followed by Ti3C2TX MXene impregnation. The aerogel features a porous three-dimensional network structure and a substantial specific surface area, facilitating broad-spectrum adsorption capabilities for various dyes and drugs. The aerogel achieved impressive adsorption capacities of 175.29 and 75.73 mg/g for cationic methylene blue and Rhodamine B dyes, and 106.33 and 93.29 mg/g for anionic methyl orange and Congo red dyes, as well as 86.25 mg/g for tetracycline hydrochloride, surpassing other reported biomass-based aerogels. Furthermore, it demonstrated effective decolorization ability for wastewater containing mixed dyes. Notably, it exhibited excellent recycling and regeneration properties, maintaining a high removal rate after multiple cycles of adsorption–desorption. The adsorption process of dye/drug by the aerogel followed Langmuir’s monomolecular layer adsorption model, exhibiting spontaneous, endothermic, and disorder-increasing behavior in alignment with the pseudo-second-order kinetic model. This study presents an efficient biomass-based aerogel for the removal of organic pollutants from wastewater.

Vapor-phase reduction synthesis of N, S co-doped graphene/MWCNT hybrid membrane for all-solid-state supercapacitors and adsorption of organic pollutants

Owing to the limited reserves of fossil fuels, many researchers are focused on seeking advanced materials to relieve the drawbacks caused by the imbalance between the supply and demand of fossil fuels. In this study, a N, S co-doped graphene/multi-walled carbon nanotubes hybrid membrane (GMHE) was synthesized by flow-directed assembly followed by vapor-phase reduction. The resulting hybrid membrane not only exhibited excellent capacitance performance, but also good adsorption capacity for organic pollutants owing to its high electrochemical activity, well-developed pore structure, and rich surface state. The assembled GMHE all-solid-state symmetric supercapacitor delivered a high power density of 6000 W·kg−1 at an energy density of 16.0 W·h·kg−1 and superior capacitance stability (retaining 97.2 % of its initial capacitance value at 3 A·g−1). The adsorption capacity of the GMHE for organic pollutants was 50 times (chlorobenzene) its own mass. In addition, the hybrid membrane exhibited remarkable reusability over in adsorption–combustion cycles. The judiciously designed bifunctional membrane material developed herein can be directly applied in energy storage and oil pollution cleanup, supporting sustainable economic development.

3D-printed MOF/MoS2 aerogel for dye adsorption and photocatalytic degradation

The escalating challenge of water resources contamination, attributed to toxic pollutants, requires urgent attention from both governments and society. Furthermore, the inefficacy of conventional water treatment methods emphasizes the critical necessity for exploring the development of affordable, renewable, and high-performance materials, which should, for instance, enable the mutual adsorption and photocatalytic degradation of organic pollutants. Here we employed the 3D printing technique to manufacture an aerogel based on alginate, gelatin, and carboxymethylcellulose incorporated with 5 and 7.5 wt % of MOF/MoS2. FTIR spectra and EDS analysis evidenced the presence of MOF/MoS2 in the structure of the aerogels, while Helium pycnometer analysis and SEM micrographs demonstrated that the aerogels presented low density and a porous structure with porosity above 80 %. The swelling test showed that the aerogels displayed a high water absorption capacity (1400 %) after 70 h of immersion. The rheology test demonstrated that elastic behavior prevails over viscous behavior (G' > G″) and the incorporation of 7.5 wt % MOF/MoS2 favored shear thinning and viscosity recovery in the hydrogel. Adsorption tests to methylene blue (employed as a model) showed that the aerogel (HD) without the presence of MOF/MoS2 and the aerogels HD/MOF/MoS2 5 % and MOF/MoS2 7.5 % showed removal efficiencies of 16.77 %, 28.66 %, and 95.86 %, respectively. Conversely, the photodegradation test showed that HD/MOF/MoS2 5 % and HD/MOF/MoS2 7.5 % had an efficiency of 89 % and HD of 80 %. Therefore, our results demonstrate that the developed aerogels are promising candidates for the adsorption and photodegradation of dye while being low-cost, environmentally friendly, and easy to manufacture.

Removal of pollutants by olive stones-derived activated carbon@Fe3O4 nanocomposites: Effect of calcination temperature on adsorption properties

This work focuses on preparing nanocomposites based on activated carbon as a matrix obtained from bio and natural source olive stones calcined at different temperatures (300,450 and 600 °C) and decorated with an ultrasonic dispersion of magnetite Fe3O4. The obtained materials (CA-300@Fe3O4, CA-450@Fe3O4, CA-600@Fe3O4) were used as adsorbents for the elimination of organic and inorganic pollutants, such as dyes (Methylene blue (MB) and Orange G (OG)) and heavy metals (Copper (Cu(II)), Nickel (Ni(II))), by varying various influencing factors (concentration, pH, temperature, contact time effect), and the adsorption data were analysed using two kinetic models (pseudo-first order and pseudo-second order) and two isotherm models (Freundlich and Langmuir). Different characterisation methods, such as FTIR, XRD, nitrogen adsorption–desorption, TGA, SEM, TEM, EDS, and zeta potential, were used. The experimental data show that all synthesised materials have proven their efficiency in the adsorption of both organic and inorganic pollutants even after five reuse cycles without any regeneration treatment. The study showed that all nanocomposites follow the Langmuir isotherm and the pseudo-second-order as kinetic model for both organic and inorganic pollutants. The most efficient nanocomposite was CA-450@Fe3O4 with a maximum adsorption capacity Qmax (564.97, 404.85, 787.4 and 625 mg/g) for the elimination of MB, OG, Cu, and Ni, respectively.

Selective adsorption of high ionization potential value organic pollutants in wastewater

It is imperative to devise effective removal strategies for high ionization potential (IP) organic pollutants in wastewater as their reduced electron-donating capacity challenges the efficiency of advanced oxidation systems in degradation. Against this backdrop, leveraging the metal-based carbon material structure meticulously, we employed metal-pyridine-N (M-N-C, M=Fe, Co, and Ni) as the electron transfer bridge. This distinctive design facilitated the ordered transfer of electrons from the adsorbent surface to the surface of high IP value pollutants, acting as a "supplement" to compensate for their deficient electron-donating capability, thereby culminating in the selective adsorption of these pollutants. Furthermore, this adsorbent also demonstrated effective removal of trace emerging contaminants (2 mg/L), displayed robust resistance to various salts, exhibited reusability, and maintained stability. These findings carry substantial implications for future carbon-based material design, offering a pathway toward exceptional adsorption performance in treating water pollution.

Surface methodology for optimized adsorption of hazardous organic pollutant from aqueous solutions via novel magnetic metal organic framework: Kinetics, isotherm study, and DFT calculations

An efficient way to remove Janus Green B (JGB) dye from contaminated water sources is using of magnetic cerium (III) metal–organic framework (MCe-MOF). Analytical methods such as PXRD, TEM, FESEM, FT-IR, PZC, and XPS were used in the characterization of the MCe-MOF microspheres in order to assess the phase, crystallinity, shape, surface characteristics, and chemical composition of the MCe-MOF material. Impressive physical characteristics of the synthesized MCe-MOF material included a high surface area of 1340.05 m2/g. Conversely, MCe-MOF’s magnetic saturation (MS) was measured at 36.47 emu.g−1. The purpose of the study was to determine if MCe-MOF could effectively remove JGB dye from wastewater by adsorption. Adsorption settings that were studied included pH, adsorbent dose, beginning dye concentration, contact time, and temperature. The JGB electrical characteristics, reactivity, and shape were ascertained through the application of density functional theory (DFT). The placement of electrophilic and nucleophilic attack sites is in good agreement with the molecular orbitals (HOMO and LUMO) and MEP results, according to DFT. Based on the findings, MCe-MOF had a high capacity for adsorbing JGB dye, with an adsorption data fit by pseudo-second-order kinetic models and the Langmuir isotherm. It was evident from the adsorption energy of 27.8 kJ.mol−1 that chemisorption was the mode of adsorption. The optimal conditions for attaining a high adsorption capacity were found to be pH 8 and 0.02 g of MCe-MOF dose. The adsorption process of JGB dye onto MCe-MOF was seen to be spontaneous, endothermic, and random, as indicated by the temperature-dependent increases in the thermodynamic parameters ΔGo, ΔHo, and ΔSo. The adsorption process was optimized through the application of Response Surface Methodology and Box-Behnken design (RSM, BBD). The successful removal of dyes from the MCe-MOF material was made possible by these methods. While π-π bonding happens through the interaction of aromatic rings, chemisorption entails the formation of chemical interactions between the adsorbate and adsorbent. Electrostatic interactions arise from the attraction or repulsion of charges between the adsorbate and adsorbent, and pore-filling happens when the adsorbate fills the adsorbent’s pores. For the removal of JGB dye from wastewater, MCe-MOF exhibits great potential as an adsorbent because of its numerous adsorption processes and high adsorption capacity.

PH-tuneable simultaneous and selective dye wastewater remediation with digestate-derived biochar: Adsorption behaviour, mechanistic insights and potential application

The use of biochar for organic pollutants adsorption has emerged as a key component in wastewater remediation research. In this study, biochar prepared from digestate was subjected to nitric acid functionalization to enhance its adsorption capacity for organic dye mixtures of methylene blue and methyl red in synthetic wastewater. Based on experimental evidence, modified biochar BC750-NM, with a micro-mesoporous structure and a specific surface area of ∼454.15 m2/g had the best adsorption performance at optimum conditions. This adsorbent exhibited both selective and simultaneous dye adsorption upon pH control, mainly attributable to a multi-interaction process in the medium. Notably, the adsorption of both methylene blue and methyl red approached 90% under acidic pH, while methylene blue was preferentially adsorbed over methyl red at alkaline pH to attain an excellent adsorption rate of 100% for methylene blue. Our approach not only yields a valuable resource for mitigating water pollution but also offers a sustainable solution for digestate management, showcasing the potential for innovative techniques to produce synergistic environmental solutions.

Yolk-shell MOF-on-MOF hybrid solid-phase microextraction coatings for efficient enrichment and detection of pesticides: Structural regulation cause performance differences

Metal-organic frameworks (MOFs) based composites with different structure-activity relationships have been widely used in the field of organic pollutant adsorption and extraction. Here, two MOF-on-MOF composites with different structures (yolk-shell and core-shell) from homologous sources were prepared by a simple in-situ growth synthesis method and structural regulation. In order to verify the effect of composite structure on the extraction capacity, the adsorption performance of the yolk-shell structure (YS–NH2-UiO-66@CoZn-ZIF) and the core-shell structured (NH2-UiO-66@CoZn-ZIF) material were compared by using them as coating material of direct immersion solid-phase microextraction (DI-SPME) to enrich six pesticides in five matrices. The results showed that because of the unique hollow hierarchical structure, high specific surface area (930.68 m2 g−1), abundant and open active sites, and synergistic and complementary adsorption forces, YS-NH2-UiO-66@CoZn-ZIF composites had the maximum adsorption amount of 36.01–66.31 mg g−1 under the same experiment condition, which was 6.81%–34.26 % higher than that of NH2-UiO-66@CoZn-ZIF. In addition, the adsorption mechanism of the prepared materials was verified and elaborated through theoretical simulations and material characterization. Under the optimized conditions, the YS-NH2-UiO-66@CoZn-ZIF-coated SPME-HPLC-UV method had a wide linear range (0.241–500 μg L−1), a good linear correlation coefficient (R2 > 0.9988), a low detection limits (0.072–0.567 μg L−1, S/N = 3) and low quantification limits (0.241–1.891 μg L−1, S/N = 10). The relative standard deviations of individual fibers and different batches of fibers were 0.47–6.20 % and 0.22–2.48 %, respectively, and individual fibers could be recycled more than 104 times. This work provided a good synthetic route and comparative ideas for exploring the in-situ growth synthesis of yolk-shell composites with reasonable structure-activity relationships.

Application of Mesoporous Silicas for Adsorption of Organic and Inorganic Pollutants from Rainwater.

Precipitation is an important factor that influences the quality of surface water in many regions of the world. The pollution of stormwater runoff from roads and parking lots is an understudied area in water quality research. Therefore, a comprehensive analysis of the physicochemical properties of rainwater flowing from parking lots was carried out, considering heavy metals and organic micropollutants. High concentrations of zinc were observed in rainwater, in addition to alkanes, e.g., tetradecane, hexadecane, octadecane, 2,6,10-trimethyldodecane, 2-methyldodecane; phenolic derivatives, such as 2,6-dimethoxyphenol and 2,4-di-tertbutylphenol; and compounds such as benzothiazole. To remove the contaminants present in rainwater, adsorption using silica carriers of the MCF (Mesostructured Cellular Foams) type was performed. Three groups of modified carriers were prepared, i.e., (1) SH (thiol), (2) NH2 (amino), and (3) NH2/SH (amine and thiol functional groups). The research problem, which is addressed in the presented article, is concerned with the silica carrier influence of the functional group on the adsorption efficiency of micropollutants. The study included an evaluation of the effects of adsorption dose and time on the efficiency of the contaminant removal process, as well as an analysis of adsorption isotherms and reaction kinetics. The colour adsorption from rainwater was 94-95% for MCF-NH2 and MCF-NH2/SH. Zinc adsorbance was at a level of 90% for MCF-NH2, and for MCF-NH2/SH, 52%. Studies have shown the high efficacy (100%) of MCF-NH2 in removing organic micropollutants, especially phenolic compounds and benzothiazole. On the other hand, octadecane was the least susceptible to adsorption in each case. It was found that the highest efficiency of removal of organic micropollutants and zinc ions was obtained through the use of functionalized silica NH2.