Column Adsorption Experiments Research Articles

Preparation of imprinted phenol gel with ultra-high adsorption capacity based on porous biochar: 5-stage tandem column, response surface method, and mechanism analysis

Wastewater from industries like petroleum refining and pharmaceuticals contains high levels of phenolic compounds. Discharging this untreated wastewater can severely pollute water bodies. To address this issue, a biochar-based composite imprinting phenol gel(MgNBC@MIP) was designed to effectively remove phenolic compounds and control phenol levels in water environments. The adjustment of the aromatic structure and pore architecture of the biochar effectively enhanced its affinity for phenolic compounds. Subsequently, the individual effects of factors such as pH, salt, and humic acid on adsorption were explored. Optimization of the adsorption process was carried out using a four-factor, three-level response surface method, yielding a theoretical formula for the adsorption amount, with a maximum adsorption capacity of 308.311 mg/g. Moreover, the adsorption of phenol and its derivatives by MgNBC@MIP followed the Langmuir isothermal model and the PSO kinetic model. A comprehensive mechanism analysis elaborated in detail on the diffusion and adsorption process of phenol from the aqueous phase to the adsorption site. Correlation FTIR and XPS analysis confirmed that π-π electron donor–acceptor interactions, hydrogen bonding, pore filling, and metal complexation were the primary driving forces for phenol adsorption. Significantly, MgNBC@MIP exhibited good reusability in the adsorption–desorption cycle. The design of a five-stage tandem column adsorption experiment opens up avenues for the industrial application of MgNBC@MIP.

Hydrophobic CHA-ZIFs with a junctional trap between cha and d6r cages for adsorption of 2,3-butanediol in aqueous solution

The adsorption and separation of diols from dilute aqueous solution using hydrophobic materials is very challenging due to the strong diol–water hydrogen-bonding interactions. Herein, we screened hydrophobic zeolitic imidazolate frameworks (ZIFs) with chabazite (CHA) topology for separation of 2,3-butanediol (2,3-BDO) and 1,3-propanediol (1,3-PDO), which had junctional and hydrophobic traps matching the two end methyl groups of the 2,3-BDO molecule. Based on CHA-ZIFs with the same small-sized ligand 2-methylimidazole (mIm) and different large-sized ligand benzimidazole derivatives (RbIm), CHA-ZIFs with larger surface areas were obtained by the addition of excess small-sized ligand mIm in the synthesis process. We showed that all of the hydrophobic CHA-ZIFs preferentially adsorbed 2,3-BDO over 1,3-PDO by static batch adsorption and dynamic column adsorption experiments. But ZIF-301 and ZIF-300 with halogen groups exhibited better adsorptive separation performance for 2,3-BDO/1,3-PDO than ZIF-302 with methyl groups. For a typical ZIF-301, its adsorption capacity for 2,3-BDO was 116.4 mg·g–1 and selectivity for 2,3-BDO/1,3-PDO was 3.8 in dynamic column adsorption of the binary-component system (2,3-BDO/1,3-PDO: 50/50 g·L–1). Computational simulations revealed that 2,3-BDO preferentially adsorbed in a trap at the junction between the cha and d6r cages of CHA-ZIFs, meaning the strong host–guest interactions. Therefore, the hydrophobic CHA-ZIFs with a junctional trap were promising candidate materials for adsorbing 2,3-BDO, which also provided a new perspective for separating diols in dilute aqueous solutions.

Preparation of porous composite hydrogel with ultra-high dye adsorption capacity based on biochar: Adsorption behaviors and mechanisms

With the continuous development of industrialization, dyes in industrial wastewater have become a serious environmental issue. To address this environmental issue, a biochar-based composite hydrogel (PAS/aBC-CD) was designed. The use of a simple composite method effectively resolves the challenge of biochar recovery. Furthermore, the modified adsorbent exhibits remarkably high adsorption capacities for all three dyes (MB: 1494 mg/g, MG: 1182 mg/g, and NR: 1031.6 mg/g). It is noteworthy that binary co-adsorption experiments have demonstrated that CrO42− can act as a bridging agent to enhance the adsorption of dyes by the adsorbent. Systematic adsorption–desorption experiments have demonstrated the outstanding recyclability of PAS/aBC-CD, maintaining 98 % of its adsorption capacity after 5 cycles. Additionally, its industrial application potential was demonstrated through column adsorption experiments. In conclusion, this study utilized a simple composite method to produce an adsorbent with high adsorption performance and industrial application potential.

Preparation of amine functionalized micro-mesoporous silicon adsorbent from fly ash and its kinetic characteristics of CO2 adsorption/desorption process

Micro-mesoporous silicon materials were prepared using silicate filtrate produced from fly ash as a silicon source. Then, the micro-mesoporous silica material was used as the carrier and amine compounds as modifiers to prepare a micro-mesoporous CO2 adsorbent. Afterwards, the structural properties, surface groups, thermal stability of micro-mesoporous silicon materials and micro-mesoporous CO2 adsorbent were studied. The results reveal that the micro-mesoporous CO2 adsorbent maintains the same micro-mesoporous structure as the micro-mesoporous silica material. And the thermal stability temperatures of adsorbent is below 383 K. Later, the CO2 adsorption performance and kinetic characteristics of adsorption process were studied through thermogravimetric analysis (TGA) and adsorption column experiments. The results indicated that the optimal CO2 adsorption capacity of 2.31 mmol/g-adsorbent was achieved at 343 K, and the adsorption capacity remained basically unchanged after 10 adsorption/desorption cycles. Dynamics studies have shown that the Avrami fraction model fits the CO2 isothermal adsorption curve very well, and the fitting results reveal that the intra-particle diffusion dominates the speed of the adsorption process. Additionally, the Yasyerli deactivation model can perfectly fit the CO2 adsorption breakthrough curve, and the fitting results indicate that the CO2 adsorption process is the deactivation process of the adsorbent. Finally, the adsorption/desorption kinetic simulation parameters can be used for the design and optimization of CO2 adsorption and desorption processes in industry.

Hyphenated Fenton-column packed nMnO-modified wood biochar for tannery effluent treatment: Adsorption mechanism and reusability study

Industrial wastewater contains a wide range of pollutants that, if released directly into natural ecosystems, have the potential to pose serious risks to the environment.This study aims to investigate sustainable and efficient approaches for treating tannery wastewater, employing a combination of hyphenated Fenton oxidation and adsorption processes. Rigorous analyses were conducted on wastewater samples, evaluating parameters like COD, sulphide, NH3–N, PO43−, NO3−, and Cr(VI). The performance of this adsorbent material was gauged through column adsorption experiments. A comprehensive characterization of the adsorbent was undertaken using techniques such as SEM, EDX, BET, FTIR, XRD, and LIBS. The study delved into varying operational parameters like bed depth (ranging from 3.5 to 9.5 cm) diameter (2.5 cm) and influent flow rate (ranging from 5 to 15mLmin-1). The experimental outcomes revealed that increasing the bed depth and decreasing the influent flow rate significantly bolstered the adsorption column's effectiveness. Breakthrough curves obtained were fitted with different models, including the Thomas and Yoon-Nelson models. The most optimal column performance was achieved with a bed height of 10.5 cm and a flow rate of 5mLmin-1. The combined process achieved removal efficiencies of 94.5% for COD, 97.4% for sulphide, 96.2% for NH3–N, 83.1% for NO3−, 79.3% for PO43−, and 96.9% for Cr(VI) in tannery effluent. This research presents a notable stride toward the development of sustainable and efficient strategies for tannery wastewater treatment.

Synthesis of stable mesoporous Zr-MOFs using pyrazine-containing ligand for efficient capture of Pb(II) in wastewater

By optimizing the reaction conditions, a zirconium-based adsorbent Zr-PzDC with pyrazine-2,5-dicarboxylic acid as the ligand was synthesized for the treatment of lead ions in an aqueous solution. SEM, EDS-Mapping, XRS and FT-IR characterization confirmed the synthesis of Zr-PzDC. Meanwhile, BET results show that Zr-PzDC is a typical mesoporous material. The analysis of the binding process of Zr-PzDC with Pb(II) in water shows that the adsorption kinetics conform to the pseudo-second-order model; The adsorption isotherm data fits well with the Langmuir model, and the maximum adsorption capacity of Pb(II) is 298.39 mg/g; The thermodynamic parameters show that the adsorption of Pb(II) in water is a spontaneous endothermic process. Combined with the XPS spectral results, physical adsorption is the main binding mode, and single-layer chemisorption is the limiting step in the adsorption process. The results of both static and dynamic column adsorption experiments show that Zr-PzDC can treat lead ions quickly and efficiently, and has excellent reusable performance, which makes Zr-PzDC have good application potential in treating lead-containing wastewater of the battery production process.

Surface and mass transfer kinetic and equilibrium modeling of Pb(II) ions adsorption on hydroxyapatite scaffold: Batch and fixed-bed column studies

This paper presents the results of a study on removal of Pb2+ ions by using hydroxyapatite (HAP) scaffold prepared by replication method. To this aim, the effects of suspension solid content and polymeric foam density on the properties of ceramic foam were investigated. The mean total porosity and apparent porosity of the optimized scaffolds were 92.67 % and 92.04 %, respectively. The Taguchi method was performed for designing batch experiments by considering three controllable variables, namely: (1) initial pH of the solution, (2) initial concentration of Pb2+ ions (C0), and (3) circulating rate of the solution (Ǭ), on the removal efficiency of Pb2+ ions as the response. Based on the obtained results from the ANOVA analysis, the removal efficiency of Pb2+ ions was mainly affected by the initial pH of the solution (90.88 %). The highest removal efficiency (99.1 %) of Pb2+ ions was obtained by optimizing the process under operating conditions of pH = 3.5, C0 = 50 mg.L−1, and Ǭ= 0.5 L.min−1. The Langmuir isotherm model with good accuracy was fitted to the equilibrium results, and the maximum adsorption capacity of 106.38 mg.g−1 was predicted for the HAP scaffold adsorbent. Kinetic studies showed that the mass transfer diffusion steps in the external film and inside the pores are fast, being the adsorption on the adsorbent sites the rate-limiting step of the kinetics, what is plausible given the high porosity of the material. Also, the primary mechanism for Pb2+ adsorption using HAP scaffold adsorbents was found to be dissolution-precipitation. The fixed-bed column adsorption experiments performed under the predicted optimum conditions of batch experiments. In comparison to the powder adsorbents tested in fixed-bed column, this adsorbent presents several advantages. These include the elimination of the requirement for mechanical separation of the shaped adsorbent from the solution after adsorption, prevention of bed clogging, and its high surface area derived from interconnected open pores.

Adsorption performance and mechanism of waste paper-derived phosphorus-rich carbon for separation of uranium from radioactive wastewater

The use of household waste-derived materials for wastewater treatment has double environmental benefit due to the availability of simultaneous disposal of household waste and wastewater. In this work, we report the facile production of phosphorus-rich carbon from waste paper as a potential adsorbent for the disposal of uranium (VI)-containing nuclear wastewater. A simple phosphoric acid activation-carbonization strategy is developed to effectively transform waste paper into carbon. The phosphorus content of the obtained carbon reaches 8.55 at% and large pores with sizes ranging from 2 to 100 nm are observed. Batch and column adsorption experiments verify that waste paper-derived carbon can efficiently adsorb uranium (VI) from aqueous solution under weakly acidic conditions. The maximum amount of uranium adsorption on the carbon attains 492 mg g−1 at pH 4.6, and adsorption of uranium (VI) on the carbon quickly reaches the equilibrium within 20 minutes. The distribution coefficient of uranium (VI) on waste paper-derived carbon is as high as 128 L g−1. The carbon can be reused for five times with uranium (VI) adsorption efficiencies above 89% and can be used for dynamic adsorption of uranium (VI) in a fix-bed column. Kinetics, thermodynamics and DFT calculations reveal a surface complexation mechanism between uranium (VI) ion and ionized phosphoric acid group. Moreover, to avoid the generation of secondary polluted water during the treatment of uranium-containing nuclear wastewater, a water-saving method is developed for the adsorption preparation and a water-free combustion method is employed for the disposal of uranium-containing spent adsorbent instead of recycling. This study demonstrates the good application potential of household waste-derived materials in wastewater treatment and provides more clues for the amalgamation of multifold subjects.

Biomass polyamine-functionalized nanocellulose-loaded covalent organic framework to construct composite aerogels for highly efficient removal of Cr (VI) and methyl orange

Heavy metal ions and organic dyes cause ecological pollution, which is a problem that needs to be solved urgently. In this study, a novel biomass polyamine-functionalized nanocellulose loaded-covalent organic framework (COF) successfully constructed a hybrid aerogel (TDB). Due to the synergistic effect of biomass polyamines and COF, a vast number of active sites are present on the surface of TDB aerogel. This made the TDB aerogel have the largest adsorption capacity (470.67 mg/g, 488.22 mg/g) and the highest removal efficiency (98.49 %, 99.51 %) for Cr (VI) or MO (methyl orange). In the binary pollutant system, TDB aerogel also showed excellent removal efficiency for Cr (VI) and MO (91.29 %, 82.84 %). The adsorption process and adsorption mechanism of TDB aerogel were analyzed by adsorption kinetics, adsorption isotherms, thermodynamics, FTIR, and XPS. Its crystalline structure also didn't change. Fixed-bed column adsorption experiments showed that TDB aerogel could effectively purify 4510 mL of wastewater that contained Cr (VI) or 4681 mL of wastewater that contained MO. Therefore, TDB aerogel can be considered a promising adsorbent for the treatment of heavy metal ions and organic dyes in wastewater.

Removal of low concentration of perchlorate from natural water by quaternized chitosan sphere (CGQS): Efficiency and mechanism research

In this study, an innovative approach utilizing betaine as a raw material was employed to effectively modify the surface of chitosan with quaternary ammonium groups. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometer (FTIR) characterization showed that the quaternary ammonium groups on betaine were successfully loaded on the chitosan surface. The effects of dosage, pH, initial perchlorate concentration, temperature and co-existing anions on the removal efficiency of perchlorate were investigated. The saturated adsorption capacity of CGQS was 35.41 mg/g under natural condition. The impact of initial perchlorate concentrations and column flow rates on the column adsorption experiments were investigated, as well as natural water tests. Sterilizing performance experiments of CGQS were carried out innovatively. Under the condition of initial concentration of 0.5 mg/L, 9 BV/h (bed volume per hour), the effluent natural water was up to standard (≤0.07 mg/L) with a treatment capacity of 210 BV/g, and the sterilizing rate of CGQS was up to 97.02%. The proposed adsorption mechanisms involved surface pore adsorption, electrostatic adsorption of quaternary ammonium groups, and ion exchange between chloride and perchlorate ions. The CGQS prepared in this work had great potential for treating trace perchlorate contamination in natural water.

Construction of 3D network aluminum sludge-based hydrogel beads: combination of macroization, amino functionalization, and resource utilization.

An aluminum sludge-based composite material was constructed against the problems of phosphorus pollution and the waste of aluminum sludge resources. Utilizing metal Ce doping and hydrogel microbeads with pore preparation, the adsorption performance of the original sludge was improved. Meanwhile, the macroscopic body was constructed, and on this basis, polyethyleneimine (PEI) was introduced to complete the amino functionalization further to enhance the adsorption of phosphorus by the adsorbent, and NH-CeAIS-10 microbeads were successfully prepared. In adsorption, microbeads with larger specific surface area and richer functional groups are better choice compared to original sludge. The results of SEM, BET, FT-IR, and XPS analyses indicate that the adsorption of phosphorus by the microbeads is mainly achieved through electrostatic interactions, ligand exchange, and the formation of inner-sphere complexes. According to the Langmuir model, the maximum phosphorus adsorption capacity of NH-CeAIS-10 was 29.56mgg-1, which was four times higher compared to native aluminum sludge. This also confirms the significant enhancement of phosphorus adsorption through the modification of aluminum sludge. Besides, in dynamic adsorption column experiments, the material exhibited up to 99% removal in simulated wastewater for up to 30days, demonstrating the great adsorption potential of NH-CeAIS-10 in engineering applications.

Dual-templating synthesis of superhydrophobic Fe3O4/PSt porous composites for highly efficient oil-water separation

Fe3O4/PSt porous composites with low density, interconnected network structure and superhydrophobic were prepared successfully by a dual-templating method, including High Internal Phase Emulsion (HIPEs) template method and the introduction of organic template species. It was worth mentioning that a novel amphiphilic di-block copolymers P(DMAEMA-b-St) were prepared as emulsifier by reversible addition fragmentation chain transfer (RAFT) polymerization method. At the same time, the effects of PS block length, emulsifier content, Fe3O4 content, DVB content and dispersed phase proportion on HIPEs droplet size and the corresponding polyHIPEs oil absorption were researched. The results showed that the oil adsorption capacity of 9.43 g/g toward toluene under optimal conditions. Subsequently, adsorption isotherm and adsorption kinetics were investigated. The results were shown that the adsorption of oil on adsorbent followed Freundlich model and pseudo-second-order (PSO) model. In addition, the adsorption experiments on a variety of oils demonstrated the wide applicability of Fe3O4/PSt porous composites. The cycling experiments proved that the Fe3O4/PSt porous composites had excellent cycling ability, were easy to recover and could be reused for multiple times. Finally, the adsorption column experiments showed that Fe3O4/PSt porous composites had powerful potential for industrial applications.

Transport of bisphenol A, bisphenol S, and three bisphenol F isomers in saturated soils.

With the limitation of the use of bisphenol A (BPA), the production of its substitutes, bisphenol S (BPS), and bisphenol F (4,4'-BPF) is increasing. Understanding the fate and transport of BPA and its substitutes in porous media can help reduce their risk of contaminating soil and groundwater systems. In this study, column and batch adsorption experiments were performed with 14C-labeled bisphenol analogs and combined with mathematical models to investigate the interaction of BPA, BPS, 4,4'-BPF, 2,2'-BPF, and 2,4'-BPF with four standard soils with different soil organic matter (SOM) contents. The results show that the transport capacity of BPS and 4,4'-BPF in the saturated soils is significantly stronger than that of BPA. Meanwhile, the mobility of the three isomers of bisphenol F exhibits variability in saturated soils with high SOM content. The two-site nonequilibrium sorption model was applied to simulate and interpret column experimental data, and model simulations described the interactions between the bisphenol analogs and soil very well. The fitting results underscore SOM's role in providing dynamic adsorption sites for bisphenol analogs. Hydrophobicity primarily accounts for the disparity in adsorption affinity between BPA, BPS, 4,4'-BPF, and soil, whereas hydrogen bonding forces may predominantly influence the differential adsorption affinity between 4,4'-BPF and its isomers and soil. The results of this study indicate that BPS and three isomers of BPF, as alternatives to BPA, have higher mobility in saturated soils and may pose a substantial risk to groundwater quality. This study enhances our understanding of bisphenol analogs' behavior in natural soils, facilitating an assessment of their environmental implications, particularly regarding groundwater contamination.

More movement with manure: increased mobility of erythromycin through agricultural soil in the presence of manure.

Antibiotic residues in the environment threaten soil and aquatic organisms and human and livestock health through the building of antimicrobial resistance. Manure spreading associated with animal agriculture is one source of environmental antibiotic residues. To better understand the risk of contamination, we studied the adsorption of erythromycin, a model macrolide antibiotic used across human and animal medicine. We conducted a series of equilibrium batch experiments to determine the kinetics and extent of adsorption and a continuous-flow column adsorption experiment to observe non-equilibrium adsorption patterns. We determined that the adsorption equilibration time to soil was approximately 72 h in our batch experiments. Erythromycin adsorbed to soil relatively strongly (K = 8.01 × 10-2 L/mg; qmax = 1.53 × 10-3 mg/mg), adsorbed to the soil in the presence of manure with less affinity (K = 1.99 × 10-4 L/mg) at a soil: manure ratio of 10:1 by mass, and did not adsorb to manure across the solid ratios tested. We observed multi-phased adsorption of erythromycin to the soil during the non-equilibrium column experiment, which was largely absent from the treatments with both soil and manure present. These results suggest that erythromycin is more mobile in the environment when introduced with manure, which is likely the largest source of agriculturally sourced environmental antibiotics.

Self-cross-linking of metal-organic framework (MOF-801) in nanocellulose aerogel for efficient adsorption of Cr (VI) in water

Chromium (Cr) poses significant hazards to both human health and the natural environment. Therefore, in this study, metal-organic framework (MOF-801) was compounded with nanocellulose aerogel for the first time. And a nanocellulose/metal-organic framework composite aerogel was developed for efficient chromium ion adsorption. The resulting aerogel has an ultra-low density (0.017 g/cm3) and high porosity (98.87%). The removal efficiency of this aerogel for Cr (VI) (93.86%) was measured to be higher than that of cellulose nanofiber aerogel (TCNF: 50.08%) and MOF-801 powder (59.86%). It was also higher than the cellulose nanocellulose aerogel prepared without MOF-801 (TMPA: 70.58%). This is because MOF-801 cross-linked with nanocellulose increased its porosity and provided a large number of adsorption sites. The maximum adsorption of Cr (VI) by this aerogel was 350.64 mg/g (5.96 mg/cm3). The adsorption mechanism was investigated by adsorption isotherms, adsorption kinetics, XPS, and FT-IR analysis. The aerogel has good reusability, with no significant loss of adsorption performance over 6 cycles. It is worth mentioning that 0.69 g (V: 7.363 cm3) of aerogel could effectively remediate 3710 mL of chromium-containing wastewater in a fixed-bed column adsorption experiment. In addition, the aerogel can effectively remove many metal ions from wastewater. As a result, the aerogel made in this study has the ability to be an effective adsorbent for metal ion removal.

Alumina microspheres for the adsorption of fatty alcohols containing oxygenates in Fischer-Tropsch synthetic oils

The efficient and economical removal of oxygenated compounds from Fischer-Tropsch synthetic oil is vital to the promotion of high-quality chemical development in the coal chemical industry. In this study, alumina microspheres with high specific surface area, high pore capacity, and small particle size were prepared. The adsorption thermodynamics, adsorption kinetics, and column adsorption experiments were systematically conducted on various fatty alcohols bearing different carbon numbers, in mixtures of α-olefins and alkanes with different carbon numbers. The competitive adsorption behavior between weakly polar, oxide-containing methyl acetate and 12-alcohols on an alumina surface was investigated to better reduce the actual system. The Freundlich model exhibited a better fit than the Langmuir model. The adsorption kinetics and proposed first-order kinetic equations fitted better to the Crank model. Comparing the adsorption effect of commercial alumina and the alumina microspheres prepared in this study, it was observed that a smaller particle size and larger pore volume reduced the internal and external diffusion resistance of adsorption, and a larger specific surface area provided more adsorption sites for the adsorption of the oxide-containing compounds. The competitive adsorption behavior of fatty alcohols and methyl acetate on the surface of γ-alumina was explored using a combination of density functional theory (DFT) calculations and experimental techniques. The results of this study can prove to be extremely useful for the efficient removal of oxide-containing compounds from Fischer-Tropsch synthetic oils.

Synergistic effects of tungstate trioxide hemihydrate decorated reduced graphene oxide for the adsorption of heavy metals and dyes and postliminary application in supercapacitor device

Simultaneously managing water pollution, energy crises, and adherence to green chemistry standards poses a significant challenge. The objective of this investigation is to synthesize a novel material suitable for adsorbing contaminants that are typically found in wastewater, and to suggest an alternative approach for managing the spent adsorbent. A tungstate trioxide hemihydrate (WO30.5H2O) decorated reduced graphene oxide (RGO) nanocomposite (RGO-WO30.5H2O NCs) was synthesized and their batch and continuous operation for the removal of heavy metal ions and dyes from synthetic wastewater was investigated. The RGO-WO30.5H2O NCs presented batch adsorption capacity (removal percentage) of 28.005 mg/g (93.35%), 26.985 mg/g (89.95%), 25.935 mg/g (86.45%), 242.69 mg/g (97.07%), 186.97 mg/g (93.48%) for Pb2+, Cd2+, Ni2+, MB and CV, respectively. The fixed-bed column adsorption experiments presented the adsorption amount in between 123 and 79 mg/g for MB and 93 to 71 mg/g for CV as the concentration varied from 100 to 50 mg/L and 52 to 30 mg/g for Pb2+, 45 to 28 mg/g for Cd2+, and 36 to 25 mg/g for Ni2+, as the concentration varied from 50 to 20 mg/L and the breakthrough curves were fitted by the Yoon-Nelson and Thomas models. After then, the spent adsorbent was repurposed for energy storage based on the “waste-to-wealth" principle to prevent secondary pollution. The nanomaterial based on WO30.5H2O NPs, RGO-WO30.5H2O NCs, Ni(II)-Adsorbed RGO-WO30.5H2O exhibited specific capacitance of 306.42, 276.96, and 241.06 F/g, respectively, at 1.25 A/g. The Ni(II)-Adsorbed RGO-WO30.5H2O showed almost comparable capacitance stability of 75% with RGO-WO30.5H2O NCs (82%) after 12000 cycles in 1 M Na2SO4. The fabricated Ni(II)-Adsorbed RGO-WO30.5H2O-based symmetric supercapacitor device displayed energy density of 47.77 Wh/kg at power density of 45 kW/kg while exhibiting specific capacitance of 90% after 10,000 cycles. This research presents a novel methodology for the utilization of spent-adsorbent in energy storage applications, showcasing a significant environmental impact towards reducing the waste generated by conventional adsorption method.

A comparative study of experimental and advanced modelling analysis for adsorption of Cd (II) from aqueous solution by Melia azedarach L. charcoal powder

The present study deals with the preparation and characterization of Melia azedarach L. twigs charcoal powder (MAT-CP) followed by batch and column adsorption experiments to appraise its Cd(II) removal efficiency from aqueous solution. The characterization of charcoal was done using XRD, FTIR, FESEM, EDX and BET analysis. Batch adsorption study was conducted with varied variables including adsorbent dose, contact time, temperature, pH and agitation speed. Resultant data was suitably fitted in Langmuir isotherm model exhibiting a maximum 196.078 mg/g adsorption capacity. Kinetic studies revealed that the adsorption followed Pseudo-second order kinetic while thermodynamic analysis (enthalpy (ΔH°), entropy (ΔS°) and Gibb’s free energy (ΔG°)) revealed the interaction to be thermodynamically favorable and endothermic. Regeneration of adsorbent was also done and the reactivated MAT-CP was repeatedly used as adsorbent. In fixed-bed column investigation, variables such as flow rate, initial metal concentration and column bed height were varied to obtain breakthrough curves (BTCs). The column adsorption was optimally obtained at 2.5 mL/min flow rate, 25 mg/L of Cd(II) concentration and 5 cm bed height. Column adsorption modeling reflected higher R2 and adsorption capacity using Thomas and Nelson-Yoon models. The present study advocates the MAT-CP as an efficient adsorbent for Cd(II) removal from aqueous solution.

Preparation and application of porous functional polymers for boron removal in seawater desalination by a mild and free-organic solvents process

The development of high-performance adsorbents to address high concentrations of boron and thus acquirement of drinkable water from seawater is a huge challenge. Most of the boron removal adsorbents reported in the literature have complex and organic solvents involved in preparation processes, which makes industrial production difficult. Herein, the porous cross-linked polyglycidyl methacrylate (CLPGMA) with a rich pore structure is prepared in one step by water-in-oil high internal phase emulsification, and then functionalized using water as a solvent to dissolve glucosamine to obtain the boron removal adsorbent. The whole preparation process is facile and free-organic solvents, making it suitable for further industrial production. The adsorbent demonstrates excellent performance in batch adsorption. Especially, we propose to combine the adsorption with reverse osmosis technology, by which the drinkable desalinated seawater can be obtained. The column adsorption experiments show that the adsorbent can rapidly remove boron from desalinated seawater at high flow rates under dynamic conditions to meet drinking water standards. This research provides a new method for the green large-scale synthesis of high-performance boron adsorbent for seawater desalination.

Highly effective recovery of palladium from a spent catalyst by an acid- and oxidation-resistant electrospun fibers as a sorbent

Palladium is not only a precious metal but also is widely used in catalyst production, therefore it is of significance to recover palladium from spent catalysts. In this paper, Nanofiber modified by 2-Thionicotinic acid (TN-Nanofiber) featuring acid- and oxidation-resistant was fabricated through electrospinning and chemical grafting, which can trap efficiently Pd(II) ions from the extremely acidic and oxidizing systems derived from the leaching of spent catalyst. The adsorption kinetic data of Pd(II) ions was well described by the pseudo-second-order model, and the times required to reach equilibrium was 60 min. The Langmuir isotherm model provided better fitting for the Pd(II) ions adsorption, and the maximum uptake capacity of TN-Nanofiber was evaluated as 348.4 mg/g for Pd(II) ions. Furthermore, the column adsorption experiments proved the feasibility of TN-Nanofiber separation of Pd(II) ions from the spent catalyst. Investigation of the adsorption mechanism demonstrated a planar quadrilateral coordination pattern between the Pd(II) ions and the adsorption sites of TN-Nanofiber, which includes one N and one S atom sourced from the adsorption sites and two Cl atoms derived from the original PdCl42−. In summary, TN-Nanofiber may serve as the next generation of emerging adsorbents to recover palladium from the strongly acidic and oxidizing systems due to its excellent performance.