Adsorption Characteristics Research Articles

Hydrogen and Cushion Gas Adsorption-Desorption Dynamics on Clay Minerals.

Transitioning toward a hydrogen (H2)-centric energy paradigm necessitates understanding the adsorption properties of clay minerals, essential constituents of reservoirs and caprocks, for efficient geological H2 storage. This study examines the adsorption characteristics of H2 on various clay minerals (montmorillonite, illite, chlorite, kaolinite, and sepiolite) at different temperatures and the adsorption of cushion gases (N2, CH4, and CO2) under reservoir conditions (313.15 K, up to 10 MPa). The results indicate that sepiolite demonstrates superior adsorption capacity under all tested conditions, surpassing montmorillonite by over 12 times at 313.15 K for H2. Illite, chlorite, and kaolinite exhibit negligible H2 adsorption. Thermodynamic analysis reveals that H2 adsorption on clay minerals is a nonspontaneous and exothermic physisorption process. H2 loss due to adsorption hysteresis in montmorillonite and sepiolite is 42.19 and 3.56%, respectively. Sepiolite may exhibit more predictable and stable sorption properties under repeated pressure variations. The H2 adsorption capacity of montmorillonite and sepiolite is merely 0.4 and 4.5% of that of CO2, respectively. This study provides valuable insights for selecting clay minerals and cushion gases for efficient geological H2 storage and natural hydrogen exploration.

Adsorption characteristics of modified bentonites for purification of anthocyanin from saffron tepal

AbstractIn this study, anthocyanin was extracted from saffron tepals utilizing the ultrasound‐assisted extraction method. The adsorbents of raw bentonite (RB), acid activation of bentonite (AA) thermal activation of bentonite (TA), and acid and thermal activation of bentonite (ATA) were employed to separate anthocyanin from solution. The influence of the operating parameters was evaluated. The isotherm study demonstrated that anthocyanin adsorption on adsorbents could be fitted better by the Langmuir equation than the Freundlich equation. A good agreement between the predicted consequences of the pseudo‐second‐order model and empirical data was provided. Thermodynamic parameters indicated that anthocyanin was adsorbed in an exothermic and physical process. Findings presented that the best adsorption performance of anthocyanin related to ATA with 2.25 mg/g adsorption capacity which was more than 1.55, 1.75, 1.88 mg/g for RB, AA, and TA, respectively. It was due mainly to the increased surface area by both thermal and acid activation of raw bentonite.

Adsorption of ethylene and 1-methylcyclopropene (1-MCP) on Al-doped graphene structure: A DFT study for gas sensing application

Ethylene is the ripening hormone of fruits and vegetables. 1-Methylcyclopropene (1-MCP) is used as the inhibitor of the ethylene actions for extending the postharvest shelf life of the plants. To control the ripening and extending the shelf life of the plants, the adsorption characteristics of ethylene and 1-MCP on Al-doped graphene structure (AlG) were investigated as a gas sensing application by density functional theory (DFT) calculations. The geometric structures were optimized, HOMO and LUMO, energy gap, adsorption energies, the density of states (DOS), electrostatic potential (ESP) and the global reactivities were calculated for different distances between the adsorbed ethylene or 1-MCP and the adsorbent AlG. Chemisorption and physisorption interactions were analyzed. For the chemisorption process of ethylene and 1-MCP on AlG, the adsorption energies were 19.34 kJ/mol and 56.53 kJ/mol, respectively. Whereas for the physisorption process, the adsorption energies of ethylene and 1-MCP were -60.16 kJ/mol and -7.32 kJ/mol, respectively. As a result, it was presented that the AlG structure has sufficient characteristics to be a good adsorbent and a gas sensor of ethylene and 1-MCP.

Enhanced Tetracycline Adsorption Using KOH-Modified Biochar Derived from Waste Activated Sludge in Aqueous Solutions.

Antibiotic pollution poses a serious environmental concern worldwide, posing risks to ecosystems and human well-being. Transforming waste activated sludge into adsorbents for antibiotic removal aligns with the concept of utilizing waste to treat waste. However, the adsorption efficiency of these adsorbents is currently limited. This study identified KOH modification as the most effective method for enhancing tetracycline (TC) adsorption by sludge biochar through a comparative analysis of acid, alkali, and oxidant modifications. The adsorption characteristics of TC upon unmodified sludge biochar (BC) as well as KOH-modified sludge biochar (BC-KOH) were investigated in terms of equilibrium, kinetics, and thermodynamics. BC-KOH exhibited higher porosity, greater specific surface area, and increased abundance of oxygen-based functional groups compared to BC. The TC adsorption on BC-KOH conformed the Elovich and Langmuir models, with a maximum adsorption capacity of 243.3 mg/g at 298 K. The adsorption mechanisms included ion exchange, hydrogen bonding, pore filling, and electrostatic adsorption, as well as π-π interactions. Interference with TC adsorption on BC-KOH was observed with HCO3-, PO43-, Ca2+, and Mg2+, whereas Cl-, NO3-, and SO42- ions exhibited minimal impact on the adsorption process. Following three cycles of utilization, there was a slight 5.94% reduction in the equilibrium adsorption capacity, yet the adsorption capacity remained 4.5 times greater than that of unmodified sludge BC, underscoring its significant potential for practical applications. This research provided new insights to the production and application of sludge biochar for treating antibiotic-contaminated wastewater.

Polyion Hydrogels of Polymeric and Nanofibrous Carboxymethyl Cellulose and Chitosan: Mechanical Characteristics and Potential Use in Environmental Remediation.

Recently, cellulose and other biomass nanofibers (NFs) have been increasingly utilized in the design of sustainable materials for environmental, biomedical, and other applications. However, the past literature lacks a comparison of the macromolecular and nanofibrous states of biopolymers in various materials, and the advantages and limitations of using nanofibers (NF) instead of conventional polymers are poorly understood. To address this question, hydrogels based on interpolyelectrolyte complexes (IPECs) between carboxymethyl cellulose nanofibers (CMCNFs) and chitosan (CS) were prepared by ele+ctrostatic cross-linking and compared with the hydrogels of carboxymethyl cellulose (CMC) and CS biopolymers. The presence of the rigid CMCNF altered the mechanism of the IPEC assembly and drastically affected the structure of IPEC hydrogels. The swelling ratios of CMCNF-CS hydrogels of ca. 40% were notably lower than the ca. 100-300% swelling of CMC-CS hydrogels. The rheological measurements revealed a higher storage modulus (G') of the CMCNF-CS hydrogel, reaching 13.3 kPa compared to only 3.5 kPa measured for the CMC-CS hydrogel. Further comparison of the adsorption characteristics of the CMCNF-CS and CMC-CS hydrogels toward Cu2+, Cd2+, and Hg2+ ions showed the slightly higher adsorption capacity of CMC-CS for Cu2+ but similar adsorption capacities for Cd2+ and Hg2+. The adsorption kinetics obeyed the pseudo-second-order adsorption model in both cases. Overall, while the replacement of CMC with CMCNF in hydrogel does not significantly affect the performance of such systems as adsorbents, CMCNF imparts IPEC hydrogel with higher stiffness and a frequency-independent loss (G″) modulus and suppresses the hydrogel swelling, so can be beneficial in practical applications that require stable performance under various dynamic conditions.

A novel potato peels waste β-cyclodextrin biocomposite for the efficient uptake of diuron and glyphosate herbicides.

A novel biocomposite (FPPW-β-CD) was prepared by a simple and sustainable method involving fine potato peel waste, β-cyclodextrin (β-CD), and green citric acid through the crosslinking reaction. The polymer was characterized using SEM, FTIR, XRD, TGA, and DSC analyses. The adsorbent performance was evaluated about the glyphosate and diuron adsorption from the aqueous solution. Pesticide removal was investigated regarding the influence of solution pH, temperature, and initial concentration of contaminants. Also, it highlights the main interactions involved in the adsorption phenomenon based on the pH effect and characteristics of adsorbent and adsorbate molecules. The maximum adsorption capacity values according to the Sips model were higher than 2000µgg-1. The pseudo-second-order and general-order models described the kinetic data well. Thermodynamic parameters indicated that pesticide removal was spontaneous and favorable. The magnitude of enthalpy variation values (27.37kJmol-1 and - 100.79kJmol-1) revealed that the glyphosate and diuron adsorption occurred through the physisorption and chemisorption, respectively. The novel biocomposite is a promising green adsorbent for the uptake of micropollutant pesticides in aqueous solutions at concentrations of µg L-1.

Peat Water Treatment Using Modified Red mud

Red mud is an alumina refinery waste residue that has been used to develop an effective adsorbent for wastewater treatment, one of which can be applied to peat water. Peat water treatment is carried out using the adsorption method. This study sought to ascertain the impact of the acid types of acid HCl and H2SO4 solution on dealumination process to the characteristics of the red mud adsorbent based on the analysis of XRF and BET instruments. In addition, this study was to determine the effect of the effect of mass variations of the red mud adsorbent on the effectiveness of peat water treatment. This research was conducted on a laboratory scale using variations in the adsorbent mass of 1 g; 3 g ; 5 g and 7 g and variation of contact time used was 15, 30, 60, and 90 minutes . The results showed an increase in the Si/Al ratio from 1.064% to 1.697% for HCl, while for H2SO41.565%. Increasing of surface area with HCl was 179.574% while using H2SO4 was 162.891%. The results of research on the adsorption process with variations in the mass of the adsorbent 1, 3, 5, and 7 grams obtained the results of peat water pH respectively were 6.6; 7.0; 7.0; and 7,1. In the Fe metal there were removal of 73.39%; 37.09%; 24.19% and -141.93%. Then for the organic matter removal efficiency were 53.07%; 50%; 44.30% and -17.98% respectively. In variation of contact time for the parameter Fe, there were removals of 29,03%, 27,41%, and 24,19% respectively. Then for organic matter the removal efficiencies were 32,46%, 54,82%, 48,25%, and 44,29%. The optimum condition based on the result obtained are the 5 g for the mass adsorbent and 30 minute for contact time. Keywords: adsorbent; dealumination; H2SO4; HCl; peat water; red mud.

PROBLEMS OF MANAGING THE IMMUNE RESPONSE UNDER CONDITIONS OF COMPETITIVE ADSORPTION, DIFFUSION PERTURBATIONS AND TEMPERATURE RESPONSE OF THE ORGANISM

Analysis of the problems associated with the rapid spread of infectious diseases indicates the need for new approaches to the diagnosis and develop- ment of effective personalized treatment programs. One of the important aspects of solving this problem is the creation of a mathematical modeling toolkit for predicting the dynamics of infectious diseases, taking into account spatial effects, concentrated effects, various mechanisms of body protec- tion in the conditions of the application of various types of therapeutic methods of treatment. An important component of complex methods of treat- ment of a wide range of infectious diseases is the use of adsorption drugs, which, along with detoxification of the body, are able to provide an addi- tional mechanism of neutralization of viral elements. In the process of using such means, not only pathogenic elements and toxins will be adsorbed, but also various types of immune agents, which will affect the dynamics of the immune response. In the paper the infectious disease model is generalized to take into account the features of competitive adsorption of antigens and immune agents in the conditions of diffusion perturbations, concentrated influences and temperature reaction of the body. By synthesizing the ideas of step-by-step procedures, asymptotic and numerical methods, an effective computational technology of step-by-step approximation of the solution of the original model singularly perturbed problem was built. The results of the computer experiments presented in the paper illustrate the features of reducing the predicted concentration of viral elements during their competi- tive adsorption together with immune agents, in particular, the effect of reducing the efficiency of the use of non-specific adsorbents. It is emphasized that taking into account the features of the action of competitive adsorption is important for making decisions regarding the formation of rational treatment programs with the complex use of adsorbing substances and immunological drugs.

A study on the corrosion inhibition impact of newly synthesized quinazoline derivatives on mild steel in 1.0 M HCl: Experimental, surface morphological (SEM-EDS and FTIR) and computational analysis

Two new quinazoline derivatives were investigated in this research, namely 12-(4-methoxyphenyl) and 3,3-dimethyl-12-(4-nitrophenyl)-3,4,5,12-tetrahydrobenzo[4,5]imidazo[2, 1-b]quinazolin-1(2 H)-one (Q-NO2). In 1 M hydrochloric acid (HCl), −3,3-dimethyl-3,4,5,12-tetrahydrobenzo[4,5]imidazo[2,1-b]quinazolin-1(2 H)-one (Q-OMe) proved to be an extremely effective corrosion inhibitor for mild steel. The maximum inhibition efficiencies of 94.7 % for Q-NO2 and 96.7 % for Q-OMe were achieved when the performance of the inhibitors was evaluated using potentiodynamic polarization (PDP), electrochemical frequency modulation (EFM) and electrochemical impedance spectroscopy (EIS). According to these findings, the Q-NO2 and Q-OMe molecules have a remarkable ability to generate a dense, resistant protective film on the mild steel surface. This protective film acted as a barrier, effectively blocking the penetration of corrosive ions and their interaction with the mild steel substrate. The adsorption characteristics of these inhibitors on the mild steel surface conform to the Langmuir adsorption isotherm. PDP experiments show that Q-NO2 and Q-OMe act as mixed-type inhibitors for mild steel in 1.0 M HCl. Surface characterization by energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) determined that a protective layer had formed on the steel surface, preventing corrosion. The experimental results were corroborated by theoretical insights from density functional theory (DFT), which further clarified the molecular adsorption processes. This work highlights the potential of Q-NO2 and Q-OMe as effective inhibitors to protect mild steel in acidic situation.

Adsorption characteristics and separation behavior of binder and binderless zeolite LiX Pellets: O2, N2, and CO2

In adsorptive gas separation process design, optimal adsorbent selection acts as a critical factor in process efficiency. This study investigated the adsorption equilibria and kinetics of O2, N2, and CO2 (weak, medium and strong affinity, respectively) and the breakthrough performance of four commercial zeolite LiX pellets (one binderless and three binder zeolite LiX pellets) because the performance of pelletized zeolites becomes different by adding binders and pelletizing methods. The adsorption isotherms at 293–323 K and up to 100 kPa were correlated with the dual-site Langmuir and Sips models. For all adsorbents, the order of adsorption amount and isosteric heat of adsorption was CO2 ≫ N2 > O2. However, differences among the four zeolite pellets were also observed, showing the highest values of the binderless zeolite LiX pellet. Furthermore, the adsorption capacity was 20–25 % smaller for CO2 and 40–50 % smaller of N2 and O2 at 100 kPa compared to pure zeolite LiX powder. According to kinetic analysis using a non-isothermal diffusion model, the adsorption rate of N2 was faster than that of CO2 for all adsorbents, showing the order difference in the low-pressure range. The kinetic difference among the zeolite pellets resulted from the effects of heat of adsorption, heat dissipation, and thermal resistance. The breakthrough performance using N2 and O2 was mainly controlled by the adsorption capacity, showing almost constant breakthrough pattern regardless of the samples. This study suggests that detailed evaluation of pelletized adsorbent is essential before designing adsorptive processes because performance of adsorbent powder would lead to under-design of the process. (255 words)

Adsorption characteristics and mechanisms of individual and a quinary mixture of heavy metal ions on novel CoFe2O4-BiFeO3 nanosorbents in water

Application of CoFe2O4-BiFeO3 nanocomposites (CFO-BFO NCs) in highly adsorptive removal of heavy metal ions (Pb(II), Co(II), Cu(II), Cd(II) and Zn(II)) by individual and simultanoeous adsorption were investigated for the first time in the present study. The characterization of CFO-BFO NCs were analyzed by using XRD, VSM, SEM, TEM and BET techniques. The CFO-BFO NCs powder consists of characteristic peaks of BFO and CFO without any trace of other crystalline phases; they were uniformly dispersed with a size of about 3–5 nm, much smaller than single – phase CFO (10–25 nm) and BFO (5–10 µm) with the surface area of 84.93 m2/g; remanence and coercivity were 14.33 emu/g, 1.99 emu/g and 195 Oe, respectively, significantly decreased compared to CFO but significantly increased compared to BFO. The single or simultaneous adsorption of a quinary mixture of Pb(II), Co(II), Cu(II), Cd(II) and Zn(II) on CFO-BFO NCs followed the Freundlich isotherm model and the pseudo-second-order kinetic model. Adsorption capacity of single heavy metal ions were in the order Pb(II) > Co(II) > Cu(II) > Cd(II) > Zn(II) while the simultaneous adsorption was in the order Pb(II) > Cu(II) > Co(II) > Zn(II) > Cd(II). The maximum adsorption capacities (qmax) of each ion in the case of simultaneous adsorption were smaller than that for cases of the single adsorption but the total qmax of ions mixture was much higher than the highest qmax of single adsorption. The simultaneous adsorption of heavy metal ions is the competition, the best selectivity is Pb(II) and the strongest competition is Cd(II), the adsorption ability reduces as the charge and radius of interfering cation increase and the ionic strength increases. The regeneration and reuse ability were good, while the adsorption efficiency slightly decreased over three recycles. The adsorption increased slightly as temperature increased. The adsorption process was spontaneous and endothermic. Adsorption of heavy metal ions on CFO-BFO NCs consists of both electrostatic and chemisorption. The applicability for real sample is good. Our results demonstrate that the CFO-BFO NCs is a prospective adsorbent to remove Pb(II), Co(II), Cu(II), Cd(II) and Zn(II) from aqueous environment.

A statistical physics-based physicochemical study of L-phenylalanine adsorption on activated carbon.

In this comparative study of the adsorption of L-phenylalanine (L-Phe) on two modified low-activated carbons (ACK and ACZ) at four temperatures (293-313K), steric and energetic characteristics of adsorption were investigated. An advanced statistical physics multilayer model involving single-layer and double-layer adsorption scenarios was developed to interpret the L-Phe adsorption phenomenon. Modeling results indicate that two and three L-Phe layers were arranged depending on the tested adsorption systems. The estimated number of L-Phe molecules per leading adsorption site varied from 1.71 to 2.09 and from 1.76 to 1.86 for systems L-Phe-ACK and L-Phe-ACZ, respectively. The results show that a multimolecular adsorption mechanism might connect this amino acid molecule on ACZ and ACK surfaces in a non-parallel location. These parameters changed as follows, according to the adsorbed quantity at saturation analysis: Qasat (L-Phe-ACK) ˃ Qasat (L-Phe-ACZ). This indicates that ACK material was more efficient and valuable for L-Phe adsorption than ACZ. It was also shown that the adsorption capacity decreases as the temperature increases, proving the exothermicity of the adsorption process. This analytical substantiation is confirmed by calculating the binding energies, suggesting the occurrence of physical bonds between L-Phe amino acid molecules and ACK/ACZ binding sites and among L-Phe-L-Phe molecules. Pore size distribution was interpreted and calculated by applying the Kelvin theory to data from single adsorption isotherms. All used temperatures depicted a distribution of pores below 2nm. The docking analysis involving L-Phe and the ACZ and ACK adsorbents reveal a significant resemblance in how receptors detect ligands. Consequently, the findings from the docking process confirm that the calculated binding affinities fall within the spectrum of adsorption energy. This study analyzed the adsorption capacity of the L-Phe through a model proposed by statistical physics formalism. Molecular docking was used to determine the various types of interactions between the two activated carbons. Two aspects, including orientation of L-Phe on the site, number of molecules per site n, interaction energy, density of receptor site, and adsorption capacity, were discussed to elucidate the influence of activation on the two adsorbents.

Bactericide adsorption by purple soil modified by decomposed liquid and humic substance from Bischofia javanica

To investigate the effect of plant decomposition products on bactericide adsorption, purple soil (P) was modified using different ratios of decomposed liquid (Dl) and humic substance (Hs) from Bischofia javanica. Isothermal adsorption characteristics of fenaminosulf and hymexazol by different Dl- and Hs-modified Ps (Dl-P and Hs–P) were studied using the batch method. The effects of pH, ionic strength, and temperature on bactericides adsorption were analyzed. The adsorption process of fenaminosulf and hymexazol on modified Ps was suitable to be described by the Freundlich model. Meanwhile, the adsorption capacity of two bactericides on Hs-Ps was higher than that on Dl-Ps. Acidic conditions and low temperatures were more favorable for the adsorption of fenaminosulf and hymexazol on modified Ps. The adsorption amount of fenaminosulf increased first and then decreased, but that of hymexazol decreased with the increase in ionic strength. The adsorption process of two bactericides was a spontaneous, exothermic entropy-increasing reaction, and the physical adsorption mechanism mainly controlled the adsorption rate. In conclusion, Dl-Ps and Hs-Ps showed potential environmental remediation applications.

Functionalized expanded graphite foam supported by PVDF skeleton for cationic dyes selectively separating and purifying

In order to fully utilize the advantages of expandable graphite (large specific surface area and porous structure), a solvent-free method was used to provide a supporting skeleton for expandable graphite through melting, bonding and solidification of polyvinylidene fluoride (PVDF). Based on its porous structure and enhanced mechanical stability, the formed PVDF/expandable graphite composite foam, amounts of functional groups were introduced throughout the foam (outside on the surface and inner side in the expandable graphite) by deposition of tannic acid (TA) and dopamine (DA), endowing it selective adsorption characteristics. The functioned foam exhibited excellent dynamic dye adsorption capacity by capturing dye molecules firmly through π-π interaction, hydrogen bonding, and charge attraction between the functional groups and dyes. Furthermore, with low zeta potential (-24.9 mV), the functional groups showed selective adsorption properties resulting in rapid separation of cationic dyes and anionic dyes. The functionalized PVDF/expandable graphite composite foam contact these two materials together in order to complement each other's advantages, showing a new research orientation for the treatment of different types of dyestuff wastewater.

Molecular simulation on competitive adsorption of ethanol, acetaldehyde and acetic acid on zeolites in humid conditions

Adsorption is a key technique for purifying volatile organic compounds (VOCs) from indoor air. Due to the complexity of multi-component VOCs and humid environment, the competitive adsorption among VOCs under the influence of water vapor remains unclear, which limits adsorbent selection and performance prediction. In this work, adsorption characteristics of typical indoor VOCs (ethanol, acetaldehyde, and acetic acid) on commercial zeolites (BETA-25 and ZSM5-300) under varying humidity were studied through molecular simulation. The simulation based on charge-corrected molecular structures and force field was validated by experiments. The unary, binary and ternary adsorption isotherms of three VOCs were obtained. At both dry and wet conditions, the VOCs with higher polarity shows greater adsorption capacity: acetic acid > ethanol > acetaldehyde. BETA-25 exhibits stronger adsorption on all three gases under dry conditions, while under wet conditions ZSM5-300 shows greater adsorption capacity of ethanol and acetaldehyde with lower polarity as compared to BETA-25. Simulation of adsorption energy and adsorbate density distribution in ternary equilibrium demonstrates the presence of water vapor alters the sorbate-sorbent interaction, particularly for ethanol and acetaldehyde showing stronger adsorption on BETA-25 than on ZSM5-300 at dry conditions but reversely at wet conditions. The lower-silica zeolite favors the adsorption of highly-polar VOC regardless of water, and the higher-silica counterpart with greater hydrophobicity facilitates adsorption of less-polar compounds in competing with water. The findings in this work can provide methodological reference for adsorbent screening and data basis for real VOCs purification applications.

Multicomponent adsorption mechanism of CO2, SO2, NO, and C7H8 from flue gases on nitrogen-doped biochar: Experimental and computational insights

The comprehensive control of CO2 and gaseous pollutants in coal-fired flue gas is urgent and difficult. As a green low-cost adsorbent, nitrogen-doped biochar has potential application in the control technology of flue gas pollutants. Still, its multi-component adsorption characteristics for flue gas are unclear. In this study, the multi-component adsorption characteristics of CO2, SO2, NO, and C7H8 on nitrogen-doped biochar were explored at different temperatures (25–120 °C), and the competitive mechanism of multi-component adsorption was revealed through continuous adsorption experiments and numerical calculation. The adsorption capacities of CO2, SO2, NO, and C7H8 by nitrogen-doped biochar can reach 38.1, 78.9, 3.1, and 245.2 mg/g, among which CO2, SO2, and C7H8 show strong competitive effects. Their adsorption capacities are decreased by 42 % (CO2), 28 % (SO2), and 27 % (C7H8) respectively compared with the single-component adsorption. This is because there are not only more C7H8 adsorption sites on nitrogen-doped carbon, but also C7H8 can partially occupy the adsorption sites of SO2 and CO2 during multi-component adsorption. Combined with the calculation results of density functional theory, the competitive ability of the three gases can be ranked as follows: C7H8 > SO2 > CO2.

Enrichment of deoxynojirimycin in mulberry using cation exchange resin: Adsorption/desorption characteristics and process optimization

Deoxynojirimycin (DNJ) is an α-glucosidase inhibitor with high food values. However, the complex and costly enrichment processes have greatly prevented its application. Herein, this study aimed to propose a simple and efficient enrichment process for DNJ from Morus alba L. extracts using cation exchange resins. The LSI and D113 resins were chosen due to their excellent adsorption and desorption properties. The adsorption characteristics agreed with the pseudo-first-order kinetic model and the Langmuir isotherm model. This adsorption was chemisorption, spontaneous, endothermic and entropy-driven. Furthermore, the concentration and pH of the extracts, desorption solvent, breakthrough and elution curves, sample loading and elution rate were investigated to optimize the enrichment process by resin column chromatography. The results also showed that the purity of DNJ was improved to 44.00 % with a total recovery of 78.21 % using the LSI-D113 combination strategy. This research demonstrated the industrial feasibility of DNJ enrichment using cation exchange resins.

Adsorption-desorption mechanisms and migration behavior of fluchlordiniliprole in four different soils under varied conditions

Utilizing infrared spectroscopy coupled with batch equilibrium methods, the adsorption and desorption characteristics of the novel Insecticide fluchlordiniliprole were assessed in four different soil types. It was found that fluchlordiniliprole’s adsorption and desorption in these soils were consistent with the Freundlich isotherm, exhibiting adsorption capacities (KF-ads) ranging from 8.436 to 36.269. Temperature fluctuations, encompassing both high and low extremes, impaired the ability of soil to adsorb fluchlordiniliprole. In addition, adsorption dynamics were modulated by several other factors, including soil pH, ionic strength, amendments (e.g., biochar and humic substances), and the presence of various surfactants and microplastics. Although capable of leaching, fluchlordiniliprole exhibited weak mobility in most soils. Therefore, it appears that fluchlordiniliprole seems to pose a threat to surface soil and aquatic biota, but a minimal threat to groundwater. Synopsis StatementThis research examines the dynamics of fluchlordiniliprole in soil, an will aid in maintaining ecological safety and managing agricultural pesticides. The study's comprehensive analysis of adsorption, desorption, and soil migration patterns significantly contributes to our understanding of pesticide interactions with diverse soil types. The results of this study will enable the development of environmentally responsible agricultural practices.

Preparation of NH2-MIL-101(Fe) Metal Organic Framework and Its Performance in Adsorbing and Removing Tetracycline.

Tetracycline's accumulation in the environment poses threats to human health and the ecological balance, necessitating efficient and rapid removal methods. Novel porous metal-organic framework (MOF) materials have garnered significant attention in academia due to their distinctive characteristics. This paper focuses on studying the adsorption and removal performance of amino-modified MIL-101(Fe) materials towards tetracycline, along with their adsorption mechanisms. The main research objectives and conclusions are as follows: (1) NH2-MIL-101(Fe) MOF materials were successfully synthesized via the solvothermal method, confirmed through various characterization techniques including XRD, FT-IR, SEM, EDS, XPS, BET, and TGA. (2) NH2-MIL-101(Fe) exhibited a 40% enhancement in tetracycline adsorption performance compared to MIL-101(Fe), primarily through chemical adsorption following pseudo-second-order kinetics. The adsorption process conformed well to Freundlich isotherm models, indicating multilayer and heterogeneous adsorption characteristics. Thermodynamic analysis revealed the adsorption process as a spontaneous endothermic reaction. (3) An increased adsorbent dosage and temperature correspondingly improved NH2-MIL-101(Fe)'s adsorption efficiency, with optimal performance observed under neutral pH conditions. These findings provide new strategies for the effective removal of tetracycline from the environment, thus holding significant implications for environmental protection.

Insight into the adsorption mechanism of arsenic and selenium by different mineral adsorbents

The adsorption characteristics of arsenic and selenium by CaO, CaCO3, MgO and Fe2O3 at different temperatures and the influence of steam are investigated using simulated flue gas by a vertical furnace. Experiments show that the adsorption capacity of CaCO3 for arsenic and selenium reached the maximum at 900 °C. Steam addition exerts a notable inhibitory impact on the adsorptive efficacy of CaO, MgO, and Fe2O3. Low-concentration steam has a certain improvement on adsorption of arsenic by CaCO3, while excessive steam will have an inhibitory effect. Based on CaCO3, the adsorption effect of composite minerals is investigated. When the mass ratio of CaCO3 and Fe2O3 is 3:1, the best adsorption is achieved, attributing to the generated Ca2Fe2O5 at high temperature. It is verified in the drop tube furnace. The relative enrichment factor of As and Se are 88.24 % and 75.11 %, respectively, which achieved efficient removal.