Adsorption Kinetics Research Articles

Surface charge alteration of charcoal derived from bamboo leaves and understanding the interaction with anionic and cationic dye

Cost-effective adsorbents derived from regenerative sources provide a sustainable solution to the pressing environmental pollution challenges. Conventional studies often rely on biochar-based adsorbents obtained at high carbonization temperatures in an induced environment. The present study explored the efficacy of carbon derived from the stems (CBS) and leaves (CBL) of bamboo plants as efficient dye adsorbents at low carbonization temperatures. CBL carbonized at 350 °C exhibited a remarkable dye adsorption efficiency of 90%, significantly outperforming CBS, which achieved only 39% efficiency. To enable the adsorption of both dyes, heterophase metal oxides, specifically Fe-doped ZnO and ZnFe2O4 were incorporated. Zeta potential measurements revealed a transition from negative to positive values with metal oxide incorporation, suggesting alterations in the surface acidity and functional group composition. The adsorption performance of the composite (WC20) sample was evaluated using Congo Red (CR) and Crystal Violet (CV) dyes. Comprehensive studies on the adsorption kinetics, isotherm modeling, and thermodynamics have been conducted to identify WC20 as the most effective composite. The equilibrium adsorption data aligned well with the Langmuir isotherm model, demonstrating maximum adsorption capacities of 65.31 mg g−1 for CR and 38.05 mg g−1 for CV at room temperature of 298 K with constant pH. Thermodynamic analysis indicated a hybrid adsorption mechanism, wherein CR adsorption was predominantly driven by chemisorption, whereas CV adsorption was governed by physisorption. Mechanistic insights have revealed that electrostatic interactions and π–π stacking play crucial roles in dye removal. These findings underscore the potential applicability of WC20 as a cost-effective and efficient adsorbent for the remediation of both cationic (CV) and anionic (CR) dyes in wastewater, highlighting its viability for future environmental management and pollution mitigation strategies.

Orange Peels as Activated Carbon Charcoal For Cu (II) Ions Elimination From Water Sources

Objectives: The goal of this work is to create inexpensive Orange Peel Activated Carbon (OPAC) for the environmentally friendly to eliminate of Cu (II) from its aqueous solution. Methods: activated carbon made by calcining orange peels at 500°C to cause them to burn. Methods: The samples were characterized using FTIR, transmission electron microscopy, and nitrogen adsorption-desorption. Cu (II) was adsorbed in a batch procedure utilizing 0.25 g of (OPAC) and 100 mL of solution with varying beginning concentrations ranging from 20–80 mg/L. The investigation focused on the effects of variables pH, temperatures, concentrations, dosages, and times on the adsorption capacity. Thermodynamic parameters were computed, adsorption kinetics were assessed using pseudo-first and pseudo-second-order were computed models, and the adsorption isotherms were fitted using the Langmuir and Freundlich models. Findings: The stretching of the hydroxyl groups is shown by peaks at 3100 and 4000 cm-1 as well as the 3300–3800 cm-1 region in the FTIR. Findings: the functionalized (OPAC). N2 adsorption isotherm revealed a hysteresis loop in the p/p0 region between 0.2 and 1. The surface area of obtained mesoporous OPAC was 0.99 nm. The maximum adsorption capacity (79.056 mg/g). Removal of Cu (II) was 99%. The adsorption process was spontaneous and less random, as indicated by the negative values of thermodynamic parameters (∆S° -14.0, ∆H°-54.76, and ∆G°-60.36 kJ.mol-1). According to the findings, orange peel has a high surface area and is highly porous, which allows it to effectively remove over 99% of harmful heavy metals from water sources. Novelty: The study proves that orange peel can be effectively used as one of the best-quality, reasonably priced, readily available, eco-friendly bio-sorbents that is also beneficial to the economy in the long run. Keywords: Orange peel, Cu (II), Adsorption, Kinetic, Thermodynamic, IFTR

Evaluation of activated carbon fiber packed-bed for the treatment of gas-to-liquid wastewater: experimental, modeling and ASPEN Adsorption simulation

AbstractThis study investigates the continuous adsorption treatment of gas-to-liquid (GTL) wastewater from the Fischer-Tropsch process using activated carbon fiber (ACF) as the adsorbent. ACF, characterized by a high surface area of 1232 m²/g, was utilized to treat actual GTL wastewater, which contains long and short-chain alcohols, fatty acids, and other hydrocarbons. Experimental analysis, packed-bed modeling and simulation using ASPEN Adsorption were employed to understand the dynamics of the adsorption process. The experimental setup involved a bench-scale column packed with specified masses of ACF, with GTL wastewater pumped upward through the column at varying flow rates. Breakthrough curves were constructed to assess column performance, with parameters, such as feed flow rate (5 and 10 mL/min) and packing mass (5 and 10 g) systematically varied. The results demonstrate a significant influence of these parameters on column performance, with higher flow rates initially accelerating adsorption kinetics. Conversely, increasing packing mass extends the duration of column saturation, improving efficiency. Empirical models, including the Yoon-Nelson and El-Naas et al. models were applied to fit the experimental data, with the latter showing superior performance in representing the adsorption mechanism within the column. Quantitative analysis of model fitting using Akaike Information Criteria (AIC) identified the Yoon-Nelson and El-Naas et al. model as the most suitable for describing the GTL wastewater/ACF system, with an AIC weight parameter of 0.33 and R2 averaging 86.5%. Furthermore, simulation results from ASPEN Adsorption exhibited strong agreement with experimental data, validating its efficacy for simulating liquid adsorption processes. The study provides valuable insights into the design and optimization of large-scale wastewater treatment systems, offering practical solutions to address global water challenges.

High-Speed Imaging of Giant Unilamellar Vesicle Formation in cDICE.

Giant unilamellar vesicles (GUVs) are widely used as in vitro model membranes in biophysics and as cell-sized containers in synthetic biology. Despite their ubiquitous use, there is no one-size-fits-all method for their production. Numerous methods have been developed to meet the demanding requirements of reproducibility, reliability, and high yield while simultaneously achieving robust encapsulation. Emulsion-based methods are often praised for their apparent simplicity and good yields; hence, methods like continuous droplet interface crossing encapsulation (cDICE), which make use of this principle, have gained popularity. However, the underlying physical principles governing the formation of GUVs in cDICE and related methods remain poorly understood. To this end, we have developed a high-speed microscopy setup that allows us to visualize GUV formation in real time. Our experiments reveal a complex droplet formation process occurring at the capillary orifice, generating >30 μm-sized droplets and only in some cases GUV-sized (∼15 μm) satellite droplets. According to existing theoretical models, the oil-water interface should allow for the crossing of all droplets, but based on our observations and scaling arguments on the fluid dynamics within the system, we find a size-selective crossing of GUV-sized droplets only. The origin of these droplets remains partly unclear; we hypothesize that some small GUVs might be formed from large droplets sitting at the second interface. Finally, we demonstrate that proteins in the inner solution affect GUV formation by increasing the viscosity and altering the lipid adsorption kinetics. These results will not only contribute to a better understanding of GUV formation processes in cDICE but ultimately also aid in the development of more reliable and efficient methods for GUV production.

Removal process of an industrial dye using a biosorbent: characterization, kinetic, equilibrium, and thermodynamic studies

Adsorption-based removal is a highly efficient environmental phenomenon employed to eliminate various dyes, such as crystal violet (CV), which is prevalently used in the textile industry and subsequently discharged into natural ecosystems. This study aims to utilize natural bentonite clay sourced from Algeria for the extraction of cationic dye (CV) from wastewater. The characterization of the bentonite was conducted using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). Evaluations assessed the impact of various parameters including pH, stirring time, temperature, and initial dye concentration on the adsorption efficiency. Optimal conditions for the maximal adsorption of CV were determined to be 430.18 mg g-1 at an adsorbent-to-dye solution ratio of 1 g L-1, pH 11.06, an equilibrium time of 40 minutes, and a temperature of 40°C. The adsorption kinetics were best described by the pseudo-second-order model, while the Freundlich isotherm model aptly described the adsorption isotherms. Thermodynamic parameters underscored the spontaneous and exothermic nature of the crystal violet removal process using raw bentonite. This research provides novel insights into the effective removal of a cationic dye from water and wastewater using Algerian bentonite clay.

Synthesis and application of MgCuAl-layered triple hydroxide/carboxylated carbon nanotubes/bentonite nanocomposite for the effective removal of lead from contaminated water

A novel multicomponent adsorbent nano-composite was synthesized by intercalating bentonite clay and carboxylated carbon nanotubes (CNT-COOH) into MgCuAl-layered triple hydroxide (MgCuAl-LTH), abbreviated as LTH/CNT-COOH/Bent. The produced nano-composite, its parental materials, and their binary combinations were characterized using various techniques. Pore filling was noted based on the BET analysis, hence, indicating effective component integration in the nano-composite structure. Further, distinct peaks appearing on the FTIR and XRD spectra of the single materials also appeared on the synthesized composites (including the binary combinations of the parental materials), hence, further indicating the successful synthesis of the targeted adsorbents. The effects of process parameters including pH, adsorbent dose, lead initial concentration and contact time on lead removal, were explored. In general, the application of LTH/CNT-COOH/Bent adsorbent yielded a significant improvement in lead adsorption capacity (∼260.8 mg/g) relative to all parental materials and their binary combinations. It was revealed that the adsorbent dose and lead initial concentration are the most significant factors affecting lead uptake onto the synthesized adsorbent and the adsorption kinetics was fast. The obtained results indicated that the Avrami kinetic and Redlich-Peterson isotherm models best fit the lead adsorption kinetics and isotherm experimental results, respectively. Furthermore, the response surface methodology (RSM) technique was employed for optimization of lead removal, achieving near complete removal (>99 %) at LTH/CNT-COOH/Bent dose of 0.5 g/L, lead initial concentration of 40 ppm and a time of 2 h. Additionally, the machine learning (ML) and the ANN based models for lead removal using LTH/CNT-COOH/Bent nano-composite yielded good predictions.

Experimental and Theoretical Studies on the Adsorption of Bromocresol Green from Aqueous Solution Using Cucumber Straw Biochar

Biochar prepared from crop straw is an economical method for adsorbing bromocresol green (BCG) from textile industrial wastewater. However, there is limited research on the adsorption mechanism of biochar for the removal of BCG. This study utilized cucumber straw as raw material to prepare biochar with good adsorption potential and characterized its physicochemical properties. Through adsorption experiments, the effects of solution pH, biochar dosage, and initial dye concentration on adsorption performance were examined. The adsorption mechanism of cucumber straw biochar (CBC) for BCG was elucidated at the molecular level using adsorption kinetics, adsorption isotherm models, and density functional theory (DFT) calculations. Results show that the specific surface area of the CBC is 101.58 m2/g, and it has a high degree of carbonization, similar to the structure of graphite crystals. The presence of aromatic rings, –OH groups, and –COOH groups in CBC provides abundant adsorption sites for BCG. The adsorption process of CBC for BCG is influenced by both physical and chemical adsorption, and can be described by the Langmuir isotherm model, indicating a monolayer adsorption process. The theoretical maximum monolayer adsorption capacity (qm) of BCG at 298 K was calculated to be 99.18 mg/g. DFT calculations reveal interactions between BCG and CBC involving electrostatic interactions, van der Waals forces, halogen–π interactions, π–π interactions, and hydrogen bonds. Additionally, the interaction of hydrogen bonds between BCG and the –COOH group of biochar is stronger than that between BCG and the –OH group. These findings provide valuable insights into the preparation and application of efficient organic dye adsorbents.

Preparation and Tumor Inhibitory Activity of Tricin from Carex Meyeriana Kunth

This study describes the purification and preparation of tricin (5, 7, 4-trihydroxy-3, 5-dimethoxyflavone) from Carex Meyeriana Kunth via adsorption and desorption using macroporous resins and high-performance liquid chromatography. Six resins were tested to evaluate the static adsorption and desorption capacities. The HPD-300 resin was selected as the adsorption material to enrich tricin because of its suitable adsorption and desorption capacities. Adsorption thermodynamics and kinetics were studied on HPD-300 resin, and the results agreed with the Langmuir model and quasi-second-order kinetics model, respectively. The parameters of the dynamic adsorption and desorption tests were then optimized. The purity of tricin increased from 2.6 mg/g to 45.1 mg/g with a recovery yield of 76.4% after purification using HPD-300 resin. Then, Prep-HPLC was used to further purify tricin. The purity of tricin reached 99.4%, with a recovery yield of 78.0% thereafter. Tricin exerts an inhibitory effect on the proliferation of various tumor cells, including gastric cancer SGC-7901 cells. It significantly suppresses cell colony formation while also altering cell cycle progression metabolism by decreasing the proportion of cells in the G0/G1 phase and increasing the proportion in the S and G2/M phases. Additionally, tricin affects the efficiency of SGC-7901 cell lactate production, ATP content, and glucose uptake. These findings suggest that tricin may impede tumor cell proliferation through its impact on cell cycle progression and energy metabolism.

Fabrication of core-shell structural Y@VTMS-DVB composites with enhanced hydrophobicity for toluene capture under humid environment

Zeolite Y serves as an effective adsorbent for VOCs capture due to its ordered porous structure, exceptional thermal stability, chemical resistance and fine-tune key properties. However, the hydrophilicity caused by the low SiO2/Al2O3 ratio seriously limits its industrial application, especially in humid environments. In this work, a series of core-shell composites Y@VTMS-DVBn were prepared through surface grafting and copolymerization. A variety of characterizations were utilized to study the structural and morphological changes of the prepared samples. The dynamic breakthrough adsorption experiment showed that the toluene uptake was significantly improved from 1.77 mg/g to 53.09 mg/g under 30 % relative humidity. Moreover, the core-shell composite exhibited excellent regeneration properties, the adsorption capacity remained 90 % under wet conditions after 6 cycles of regeneration. Adsorption kinetic analysis revealed that the adsorption behavior of toluene on the prepared adsorbents was primarily physical adsorption. These results show that the core-shell composite is a promising candidate for VOCs removal in industrial application.

Model and simulations of the effects of polyelectrolyte-coated electrodes in capacitive deionization.

The problem of ion transport in porous media is fundamental to many practical applications such as capacitive deionization, where ions are electrostatically attracted to a porous electrode and stored in the electric double layer, leaving a partially desalinated solution. These electrodes are functionalized to achieve maximum efficiency: it is intended that for each depleted electron one ion is removed. For this purpose, the surface is coated with a polyelectrolyte layer of the same sign as the electronic charge. In this work, the movement of ions from the solution to the soft or polyelectrolyte-coated electrodes is studied. For this purpose, a one-dimensional model is used to study the electric and diffusive fluxes produced by the application of an electric field and the storage of these ions in the micropores. The partial differential equationsgoverning the process are numerically solved using the explicit Euler method. The results of the model indicate that the number of ions removed using soft electrodes is approximately 15% greater than that achieved with bare electrodes. Ion adsorption kinetics show that coated electrodes provide slightly slower adsorption compared to bare electrodes. Regarding the charging time of the micropores, it can be seen that it is a faster process (characteristic time of 100s) compared to the time in which the ion concentration reaches equilibrium: electromigration is faster than diffusion. Comparing the situations with and without polyelectrolyte coating, it is observed that saturation in the micropores is reached earlier when the electrodes are coated. Concerning the cell geometry, it has been found that the characteristic time is proportional to the length of the spacer and inversely proportional to the length of the electrodes. With regard to microporosity, the rate of the process is approximately constant, irrespective of the number of micropores. Moreover, the number of adsorbed ions strongly depends on their initial concentration. Finally, the analysis of the ionic diffusion coefficient is determinant in the kinetics of the process: Taking into account the tortuosity of the porous electrode, which directly affects the diffusion in the channel, is fundamental to obtain model predictions close to reality.

Investigation of MO Adsorption Kinetics and Photocatalytic Degradation Utilizing Hollow Fibers of Cu-CuO/TiO2 Nanocomposite.

This comprehensive study explores the kinetics of adsorption and its photocatalytic degradation of methyl orange (MO) using an advanced copper-decorated photocatalyst in the form of hollow fibers (HFs). Designed to boost both adsorption capacity and photocatalytic activity, the photocatalyst was tested in batch experiments to efficiently remove MO from aqueous solutions. Various isotherm models, including Langmuir, Freundlich, Sips, Temkin, and Dubinin-Radushkevich, along with kinetic models like pseudo-first and pseudo-second order, Elovich, Bangham, and Weber-Morris, were utilized to assess adsorption capacity and kinetics at varying initial concentrations. The results indicated a favorable MO physisorption on the nanocomposite photocatalyst under specific conditions. Further analysis of photocatalytic degradation under UV exposure revealed that the material maintained high degradation efficiency and stability across different MO concentrations. Through the facilitation of reactive oxygen species generation, oxygen played a crucial role in enhancing photocatalytic performance, while the degradation process following the Langmuir-Hinshelwood model. The study also confirmed the robustness and sustained activity of the nanocomposite photocatalyst, which could be regenerated and reused over five successive cycles, maintaining 92% of their initial performance at concentrations up to 15 mg/L. Overall, this effective nanocomposite photocatalyst structured in the form of HF shows great promise for effectively removing organic pollutants through combined adsorption and photocatalysis, offering valuable potential in wastewater treatment and environmental remediation.

An Investigation of Lanthanum Recovery from an Aqueous Solution by Adsorption (Ion Exchange)

Lanthanum (La(III)) is one of the high-demand rare earth elements with applications in various products. However, La(III) in mining waste streams and electronic waste also poses environmental and health concerns. Therefore, the recovery of La(III) in the waste is needed. In the present study, the adsorption of La(III) with Dowex 50W-X8, Amberchrom50WX4, Amberlyst 15, and Amberchrom 50WX2 was evaluated using a shaker water bath. Dowex 50W-X8 was found to be the best adsorbent and was used to investigate the effect of the shaker speed (RPM = 50–150), adsorbent dosage (1.0–4.0 g), pH (2.0–7.0), and temperature (20–40 °C) on adsorption. La(III) adsorption was found to increase with the shaker speed, as expected. On the other hand, the adsorption capacity decreased with the adsorbent amount. Also, the highest La(III) adsorption was observed at pH = 6.0. La(III) percentage removal did not vary significantly with a temperature from 20 °C to 40 °C. However, the first-order kinetic rate constant decreased moderately with increases in temperature. The adsorption of La(III) by Dowex 50-X8 followed the Freundlich isotherm model better than the Langmuir model. In addition, the adsorption kinetics were represented well by the pseudo-first-order kinetic model. Moreover, enthalpy and Gibbs free energy changes were found to be negative, indicating an exothermic and thermodynamically favorable adsorption process.

Porous Organic Cage as an Efficient Platform for Industrial Radioactive Iodine Capture

AbstractHerein, we firstly develop porous organic cage (POC) as an efficient platform for highly effective radioactive iodine capture under industrial operating conditions (typically ≥150 °C), ≤150 ppmv of I2). Due to the highly dispersed and readily accessible binding sites as well as sufficient accommodating space, the constructed NKPOC‐DT‐(I−) (NKPOC=Nankai porous organic cage) demonstrates a record‐high I2 uptake capacity of 48.35 wt % and extraordinary adsorption capacity of unit ionic site (~1.62) at 150 °C and 150 ppmv of I2. The I2 capacity is 3.5, 1.6, and 1.3 times higher than industrial silver‐based adsorbents Ag@MOR and benchmark materials of TGDM and 4F‐iCOF‐TpBpy‐I− under the same conditions. Furthermore, NKPOC‐DT‐(I−)Me exhibits remarkable adsorption kinetics (k1=0.013 min−1), which is 1.2 and 1.6 times higher than TGDM and 4F‐iCOF‐TpBpy‐I− under the identical conditions. NKPOC‐DT‐(I−)Me thus sets a new benchmark for industrial radioactive I2 adsorbents. This work not only provides a new insight for effectively enhancing the adsorption capacity of unit functional sites, but also advances POC as an efficient platform for radioiodine capture in industry.

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.

Under Water Superelastic Porous Nanofibrous Sponge for Efficient RNA Separation and Purification.

Developing monolithic materials for chromatography columns with a novel interconnected porous structure is vital for the enhancement of the separation efficiency of RNA purification processes. Herein, a porous nanofibrous sponge (PNFS) is constructed by freeze molding and freeze-drying a nanofiber dispersion with ethylene vinyl alcohol copolymer nanofibers as the skeleton, chitosan (CS) and polyethylenimine (PEI) as the binders, and glutaraldehyde (GA) as the crosslinking agent. The results show that when the CS content of the dispersion is 1.5 wt %, PNFS demonstrates a high static adsorption capacity of 406.5 mg/g (30.7 mg/m2) and a dynamic adsorption capacity of 382.6 mg/g (28.9 mg/m2) at a flow rate of 1 mm/min. Moreover, PNFS shows a high specific adsorption performance toward RNA in the presence of bovine serum albumin, lecithin, or DNA by adjusting the solution pH value and the method of gradient elution. Besides, PNFS presents exceptional performance in the rapid separation of RNA from HT22 cells without degradation. This result can be attributed to optimized morphology, pore structure, and comprehensive performance of PNFS, benefiting from the synergistic effect of the highly oriented porous structure and CS-PEI interaction derived from the high-density adsorption ligands on the channel walls of PNFS. This work provided an efficient strategy to handle the permeability/adsorptivity trade-off for ion-exchange chromatographic materials.

Sequential super-assembled nanomotor adsorbents for NIR light-Powered blood lead removal

Hemoperfusion is a common treatment for lead poisoning, where hemoperfusion adsorbents are used to remove lead ions from blood. However, traditional hemoperfusion adsorbents often suffer from limited efficiency and poor biocompatibility, reducing their effectiveness for human use. To address these limitations, we developed a novel photothermal nanomotor adsorbent through a controllable sequential super-assembly strategy. Gold nanoparticles (Au NPs) were incorporated into the nanochannels of halloysite nanotubes (HNTs), followed by modification of the outer HNT surface with polydopamine (PDA) and 2,3-dimercaptosuccinic acid (DMSA), forming Au@HNTs@PDA-DMSA. This nanomotor adsorbent leverages the photothermal properties of Au NPs to achieve self-propulsion via thermophoresis under near-infrared (NIR) light irradiation. The performance of this nanomotor was evaluated for Pb(II) removal in both aqueous solutions and human blood samples, reaching adsorption equilibrium within 20 min and a maximum capacity of 45.980 mg/g. The adsorption kinetics followed a pseudo-second-order model with a high fitting coefficient (R2 = 0.999), and the Langmuir model fit better than the Freundlich model, indicating monolayer adsorption. Notably, when driven by 808 nm NIR light at 1.0 W cm−2, the Au@HNTs@PDA-DMSA nanomotors showed a significantly enhanced adsorption capacity of 151.769 mg/g, improving blood lead removal efficiency by 1.80 times compared to non-irradiated conditions. Furthermore, the addition of sulfhydryl and carboxyl groups from DMSA provided more active sites, leading to a 9.76-fold increase in lead removal compared to passive adsorbents using HNTs. In vitro tests confirmed the excellent biocompatibility and biosafety of the nanomotor adsorbent, achieving a blood lead removal rate of 91.25 %. This advancement overcomes the limitations of traditional lead adsorbents, offering a promising solution for more effective lead detoxification in clinical and environmental settings.

Hydrothermal fabrication of composite chitosan grafted salicylaldehyde/coal fly ash/algae for malachite green dye removal: A statistical optimization

In this study, chitosan grafted salicylaldehyde/coal fly ash/algae (Chi-SL/CFA/Alg) was synthesized by assistance of hydrothermal process to be an effective adsorbent to remove cationic dye (malachite green: MG) from water. The physicochemical properties of the Chi-SL/CFA/Alg biomaterial were examined using SEM-EDX, pHpzc, specific surface area (BET), and FTIR analyses. The optimization process of the adsorption operation parameters for MG removal by Chi-SL/CFA/Alg were optimized using a Box-Behnken design (BBD). The selected adsorption operation parameters Chi-SL/CFA/Alg dosage (A: 0.02–0.1 g/100 mL), solution pH (B: 4–8), and contact time (C: 20–360 min). Analysis of variance (ANOVA) test was applied to determine the significant interaction between the adsorption operation parameters and to validate BBD output. The adsorption kinetics and isotherms of MG dye by Chi-SL/CFA/Alg were well described by pseudo-second order (PSO) kinetic and Freundlich isotherm model respectively. Thus, the maximum adsorption capacity (qmax) of MG dye by Chi-SL/CFA/Alg was found to be 493.7 mg/g at basic pH environment (pH = 8) and working temperature 25 °C. The adsorption mechanism can be ascribed to various interactions, including hydrogen bonding, π-π interactions, electrostatic attraction, and n-π interactions. Thus, Chi-SL/CFA/Alg can be considered as preferable and potential adsorbent for removing cationic dye from aqueous environment.

Inorganic porous carbon as the supporter of H2TiO3 via in-situ polymerization synchronous conversion for lithium recovery from aqueous solutions

The extraction of lithium from liquid minerals, such as salt lake brines and underground brines, has garnered extensive interest due to its eco-friendly and cost-effective properties. However, the effectiveness of this method is constrained by the stability and capacity of the materials. Herein, a new-type inorganic carbon-supported H2TiO3 adsorbent was developed by a novel in-situ polymerization synchronous conversion strategy. It was found that when resorcinol and formaldehyde containing Li2CO3 and TiO2 were polymerized in-situ and then calcined at 973.15 K, the resin was successfully carbonized to obtain the carbon supporter with a low degree of disorder, and the Li2CO3 and TiO2 in the supporter were synchronously converted into Li2TiO3 and uniformly dispersed in the carbon matrix. Because of the large specific surface area and strong hydrophilicity of the carbon supporter, the material exhibited a maximum Li+ adsorption capacity of 52.14 mg·g−1, which was far higher than that of inorganic composite materials reported at present. Even the equilibrium adsorption capacity for Li+ at a low concentration of 29.26 mg·L−1 reached 28.51 mg·g−1. Following adsorption, the Li+ in the material was easily eluted by 0.25 mol·L−1 HCl, and the elution rate was more than 90 % within 2 h. Dynamic adsorption using a fixed-bed was also performed at 298.15 and 343.15 K, and the adsorption capacity for the same concentration of Li+ was 7.08 and 9.44 mg·g−1, respectively. Because of the high capacity for low-concentration Li+ and the promoting effect of temperature on adsorption, the material is well-suited for recovering Li+ from liquid resources, particularly from geothermal water with high temperatures and low Li+ concentrations.

ACFs-NH2 developed for dispersive solid phase extraction combined with Py-GC/MS for nanoplastic analysis in ambient water samples

Accurate determination of nanoplastics (NPs) in aquatic ecosystems constitutes a challenge for which highly sensitive analytical methods are necessitated. Herein, a sample pretreatment based on self-made amino-functionalized activated carbon fibers (ACFs-NH2) dispersive solid-phase extraction (DSPE) allows for high-recovery, followed by high-sensitivity detection of NPs by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The developed methodology allowed low detection limits (20–100 μg/L) to be achieved quickly in a few steps. Under optimal conditions, ACFs-NH2 (12.5 mg) was able to recover ≥98.45 % of polystyrene (PS) nanoplastics at high concentration (100 mg/L) in 10 mL seawater. Based on the high adsorption performance of materials, the adsorption dynamics and isotherms were determined to infer the interaction mechanism of PSNPs on ACFs-NH2. After adsorption, the target on the surface of the adsorbent can be directly pyrolyzed, which can simplify the operation steps and avoid the elution of organic solvents, making the process more environmentally friendly. This strategy is feasible for the analysis of trace NPs in water systems.

Exploring the Mechanism of 4-Hydroxy-1,3,5-triazine-6-thiol Collector on Depressant-Free Flotation Separation of Galena from Sphalerite.

The flotation separation of galena from sphalerite was commonly implemented under pH > 10.5, which led to the consumption of lime. In this paper, 2-diethylamine-4-hydroxy-1,3,5-triazine-6-thiol (DEHTT) was synthesized and introduced as a highly selective collector to perform the depressant-free flotation separation of Pb/Zn sulfide minerals. The microflotation results indicated that 8.0 × 10-7 mol/L DEHTT recovered 94.17% galena and 26.67% sphalerite from their mixture at pH 8.5 regulated by Na2CO3, and under the same conditions, sodium isobutyl xanthate (SIBX) floated out 94.94% galena and 50.41% sphalerite, deducing a superior flotation selectivity of DEHTT in comparison to SIBX. In situ AFM images displayed the more preferable adsorption of DEHTT on galena in comparison to that on sphalerite. The results of adsorption thermodynamics and kinetics inferred that the adsorption of DEHTT onto the galena surface was a spontaneous endothermic chemical process. XPS further indicated that DEHTT combined with interface Pb atoms to form the -S-Pb and -O-Pb bonds. The special affinity of DEHTT to galena achieved the selective flotation separation of galena from sphalerite without the addition of lime and depressants.