Favorable Adsorption Capacity Research Articles

Long-Term Selective Photoelectrochemical Glycerol Oxidation via Oxygen Vacancy Modulated Tungsten Oxide with Self-Healing.

The photoelectrochemical selective oxidation of biowaste glycerol into the high value-added material, along with hydrogen production, holds significant promise for advancing renewable and sustainable energy technologies. Here, the surface oxygen state of tungsten oxide is modified to selectively oxidize glycerol into glyceraldehyde, a high-value-added material, and the selectivity is maintained over a prolonged period using the photo-stimulated self-recovery capability. The surface-coordinated photoelectrode exhibits high charge transfer efficiency to glycerol and favorable glycerol adsorption capacity, enabling the selective conversion of glycerol. At 1.2 VRHE in a 2m glycerol electrolyte adjusted to pH 2, the tungsten oxide photoelectrode achieves a photocurrent density of 2.58mA cm-2 and a production rate of 378.8mmol m-2h-1 with selectivity of 86.1%. The high selectivity is preserved for 18 h by utilizing the self-healing capability of tungsten oxide to restore initial states modified by photoelectrochemical oxidation. This work sheds light on the design of highly efficient metal oxide photoelectrodes for selective biomass oxidation over extended periods.

Fabrication of carbonized derivatives from a novel azo polymer as a precursor for the layered adsorption of iodine and bromine

A nitrogen-rich polymer (AZO-TPA) was synthesized and employed as a precursor for calcined carbonized derivatives. After this polymer was activated with KOH, it was doped separately with melamine and urea, both of which are rich in carbon and nitrogen, and nine distinct carbonized derivatives were obtained through carbonization at various temperatures. Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) characterization revealed that the carbonized structures were rich in nitrogen functional groups, including pyridinic-N, pyrrolic-N, and N+–O- (nitrogen oxides), and possess additional active sites such as –OH and CO groups. The adsorption of bromine, iodine, and the fractional adsorption of bromine/iodine were investigated via the prepared carbonized derivatives. The results indicated that the polymer was successfully doped with urea and yielded carbonized derivatives at 600 °C (AZO-TPAU-600) which exhibited favorable adsorption capacity, particularly after KOH activation and urea doping (iodine vapor: 2782 mg g−1; bromine/iodine: 1854 and 867.55 mg g−1). In addition, the AZO-TPA-600 exhibited high selectivity for bromine adsorption in I2–Br2/cyclohexane solution, and the carbonized derivatives loaded with iodine/bromine could be efficiently desorbed via organic solvents, the adsorption capacity remains above 75 % even after 4 cycles. Finally, the adsorption mechanism was explained in detail.

Enhanced adsorption of dye wastewater by low-temperature combined NaOH/urea pretreated hydrochar: Fabrication, performance, and mechanism.

The highly stable biomass structure formed by cellulose, hemicellulose, and lignin results in incomplete conversion and carbonization under hydrothermal conditions. In this study, pretreated corn straw hydrochar (PCS-HC) was prepared using a low-temperature alkali/urea combination pretreatment method. The Massloss rateof cellulose, hemicellulose, and lignin from pretreated biomass, as well as the effects of the pretreatment method on the physicochemical properties of PCS-HC and the adsorption performance of PCS-HC for alkaline dyes (rhodamine B and methylene blue), were investigated. The results showed that the low-temperature NaOH/urea pretreatment effectively disrupted the stable structure formed by cellulose, hemicellulose, and lignin. NaOH played a dominant role in solubilizing cellulose and the combination of low temperature and urea enhanced the ability of NaOH to remove cellulose, hemicellulose, and lignin. Compared to the untreated hydrochar, PCS-HC exhibited a rougher surface, a more abundant pore structure, and a larger specific surface area. The unpretreated hydrochar exhibited an adsorption capacity of 64.8% for rhodamine B and 66.32% for methylene blue. However, the removal of rhodamine B and methylene blue by PCS-BC increased to 89.12% and 90.71%, respectively, under the optimal pretreatment conditions. The PCS-HC exhibited a favorable adsorption capacity within the pH range of 6-9. However, the presence of co-existing anions such as Cl-, SO42-, CO32-, and NO3- hindered the adsorption capacity of PCS-HC. Among these anions, CO32- exhibited the highest level of inhibition. Chemisorption, including complexation, electrostatic attraction, and hydrogen bonding, were the primary mechanism for dye adsorption by PCS-HC. This study provides an efficient method for utilizing agricultural waste and treating dye wastewater.

Unusually large microporous HKUST-1 via polyethylene glycol-templated synthesis: enhanced CO2 uptake with high selectivity over CH4 and N2.

Porous solids with highly microporous structures for effective carbon dioxide uptake and separation from mixed gases are highly desirable. Here we present the use of polyethylene glycol (20,000g/mol) as a soft template for the simple and rapid synthesis of a highly microporous Cu-BTC (denoted as HKUST-1). The polyethylene glycol-templated HKUST-1 obtained at room temperature in 10min exhibited a very high Brunauer-Emmett-Teller (BET) surface area of 1904 m2/g, pore volume of 0.87 cm3/g, and average micropore size of 0.84nm. However, conventional HKUST-1 exhibits a BET surface area of 700-1700 m2/g confirming the advantages of using this method. X-ray powder diffraction and electron microscopy analysis confirm the formation of highly crystalline and uniform octahedral particles with sizes ranging from 100nm to 120µm. Adsorption isotherms recorded at temperatures between 273 and 353K and pressures up to 40bar revealed a more favorable adsorption capacity of HKUST-1 for CO2 vs. CH4 and N2 (708mg (CO2)/g, 214mg (CH4)/g and 177mg (N2)/g at 298K and 40bar). The Langmuir, isotherm model, and isosteric heats of adsorption were evaluated. The CO2 interaction at PEG-templated HKUST-1 is physical, exothermic, and spontaneous with DH° = - 6.52kJ/mol, DS° = - 13.72J/mol, and DG° = - 2.43kJ/mol at 298K at 40bar. The selectivities in equimolar mixtures were determined as 53 and 24, respectively, for CO2 over N2 and CH4. CO2 adsorption-desorption tests reveal high adsorbent reusability. The cost-effective and quickly prepared PEG-templated HKUST-1 demonstrates high efficacy as a gas adsorbent, particularly in selectively capturing CO2.

Highly Selective Pb(II) Adsorption by DTPA-Functionalized Graphene Oxide/Carboxymethyl Cellulose Aerogel.

Graphene oxide (GO) exhibits a strong adsorption capacity for the removal of heavy metal ions from liquids, making it a topic of increasing interest among researchers. However, a significant challenge persists in the preparation of graphene oxide-based adsorbents that possess both high structural stability and excellent adsorption capacity. In this paper, a green and environmentally friendly ternary composite aerogel based on graphene was successfully synthesized. The adsorption capacity of graphene oxide was enhanced through diethylenetriaminepentaacetic acid modification, while the incorporation of composite carboxymethyl cellulose improved the structural stability of the composite aerogel in liquid. The composite aerogel demonstrates robust interactions between its components and features a multiscale porous structure. Adsorption tests conducted with Pb(II) revealed that the GO/DTPA/CMC (GDC) composite aerogel exhibits a favorable adsorption capacity. The study of adsorption kinetics and isotherms indicated that the adsorption process follows the quasi-secondary adsorption model and Freundlich adsorption model, suggesting a chemical multilayer adsorption mechanism, and the maximum adsorption capacity for Pb(II) ions was 521.917 mg/g based on the quasi-quadratic kinetic model fitting. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analyses, performed before and after adsorption, confirmed that the adsorption of Pb(II) primarily occurs through chelation, complexation, proton exchange, and electrostatic interactions between ions and active sites such as hydroxyl and carboxyl groups. This study presents an innovative strategy for simultaneously enhancing the adsorption properties of graphene oxide-based composite aerogels and ensuring solution stability.

Avaliação do potencial de adsorção de rejeitos de mineração de ferro e seu efeito na germinação de raphanus sativus

ABSTRACT The objective of this work was to evaluate the physicochemical and adsorptive characterization of Fe tailing collected in the district of Brumadinho; and verify its effect on Raphanus sativus germination. The material was collected on the surface layer (0-20 cm) and disintegrated for pH, redox potential – Eh, electrical conductivity – EC, OM, cation exchange capacity – CEC, specific surface area – SSA and functional groups characterization. Adsorption studies were conducted using methylene blue (MB). The results of the adsorption studies were analyzed using kinetic models (Elovich, pseudo-first order – PFO and pseudo-second order – PSO) and isotherm models (Freundlich, Langmuir and Sips). The tailing has an acidic pH (5.60), negative ΔpH (-0.30) and low CEC (1.85 cmolc g-1). A high MB adsorption efficiency (96%) was verified. The Elovich model (0.9248<R2<0.9858) best represented the chemical kinetics, and the Freundlich model best describes the MB adsorption process in the tailing (R2 = 0.9609). The maximum adsorption capacity (qm) was equal to 15.08 mg g-1. The presence of Fe tailing positively influenced the germination of R. sativus seeds (73.8%), but stem and root growth were inferior when compared to seedlings cultivated in compost substrate. It is concluded that the material has favorable cationic adsorption capacity, which can benefit soil fertilization. However, R. sativus development was minor in Fe tailing substrate, probably due to low CEC, OM and nutrient availability.

Preparation of C=C polymerization-oriented magnetic protein molecularly imprinted polymer and the application for membrane flux improvement

This study aims to prepare a novel C=C polymerization-oriented magnetic protein molecularly imprinted polymer (MMIP) to improve membrane flux by adsorbing protein-type membrane foulants. The adsorption capabilities of MMIP were assessed by batch experiments, and the oriented polymerization and adsorption mechanisms were further revealed by density functional theory (DFT). The findings suggested that the MMIP exhibited a favorable adsorption capacity (35.9 mg/g) and high specificity (imprinting factor, IF = 2.2) to bovine serum albumin (BSA), and showed an impressive adsorption capacity (21.2 mg/g) to protein-type substances in soluble microbial products (SMPs) derived from a functioning membrane bioreactor. Consequently, the MMIP reduced the filtration resistance by approximately 91.6 % compared to the control group and improved the membrane flux. Moreover, the data confirmed that the adsorption was a monolayer adsorption process in which chemical interactions dominated the rate-limiting step. DFT calculations proved that the functional monomer chain reactions predominantly occurred on C=C bonds in the oriented polymerization and the hydrogen bonding was identified as the main interaction between MMIP and protein in the adsorption. These findings suggested that the MMIP holds great potential as a recyclable adsorbent for effectively improving membrane flux through the selective adsorption of protein-type membrane foulants.

Reinforced dentin remineralization via a novel dual-affinity peptide

ObjectivesIn light of the constantly flowing saliva, anti-caries remineralization agents are inclined to be taken away. Owing to their limited residence time, the remineralization effect is not as desirable as expected. Hence, our study aimed to synthesize a novel peptide (DGP) with high affinity to both collagen fibrils and hydroxyapatite, and investigated its dentin remineralization efficacy in vitro and anti-caries capability in vivo. MethodsDGP was synthesized through Fmoc solid-phase reaction. The binding ability and interaction mechanism of DGP to demineralized dentin were investigated. Dentin specimens were demineralized, then treated with DGP and deionized water respectively. The specimens were incubated in artificial saliva and in-vitro remineralization effectiveness was analyzed after 14 days. The rat caries model was established to further scrutinize the in-vivo efficacy of caries prevention. ResultsDGP possesses an enhanced adhesion force of 12.29 ± 1.12 nN to demineralized dentin. The favorable adsorption capacity is ascribed to the stable hydrogen bonds between S2P-101 and ASP-100 of DGP and GLY33 and PRO-16 of collagen fibers. Abundant mineral deposits and remarkable tubule occlusion were observed in the DGP group. DGP-treated dentin obtained notable microhardness recovery and higher mineral content after a 14-day remineralization regimen. DGP also demonstrated potent caries prevention in vivo, with substantially fewer carious lesions and significantly lower Keyes scoring. SignificanceDGP proves to possess a high affinity to demineralized dentin regardless of saliva flowing, thus enhancing remineralization potency significantly in vitro and in vivo, potential for dental caries prevention and combatting initial dentin caries clinically.

Regulating steric hindrance in difunctionalized porous aromatic frameworks for the selective separation of Pb(II)

Efficient and selective removal of Pb(II) from wastewater with complex matrix remains a challenging task. Porous aromatic frameworks (PAFs) with predesigned functional building blocks provide a favorable platform for the selective separation of Pb(II). Herein, the bifunctional SPAFs with the introduction of -OH and -SO3H were synthesized through rationally optimizing their steric hindrance. As a result, the SPAF-0.75 exhibits favorable adsorption capacity of Pb(II) (212.34mg g-1), which is 22 times larger than pristine framework. Competition experiment indicates that SPAF-0.75 possess the selective removal of Pb(II) without interfering from co-existing metal ions. The removal rate of SPAF-0.75 still retain at 100% after six successive cycles. The DFT calculation illustrates that -OH and -SO3H are co-participate in the process of capturing Pb(II), revealing SPAF-0.75 preferred removal of Pb(II) owing to the lowest adsorption energy (ΔEab= -3.99 eV). This study extend the understanding of the structure-property relationship and facilitate new possibilities for PAFs.

A novel hydrangea-like magnetic composite Fe3O4@MnO2@ZIF-67 for efficient selective adsorption of Pd(II) from metallurgical wastewater

The selective adsorption of palladium from wastewater is a feasible solution to solving palladium pollution and resource scarcity. Because traditional solvent extraction methods often involve the use of considerable amounts of organic solvents, research is focused on investigating adsorption techniques that can selectively remove palladium from wastewater. In this paper, the magnetic composite Fe3O4@MnO2@ZIF-67 was synthesized and its performance for the adsorption of Pd(II) in acidic water was investigated. Fe3O4@MnO2@ZIF-67 was characterized by various analytical methods such as TEM, SEM, EDS, BET, XRD, FTIR, zeta potential analysis, VSM, and TGA. The effects of palladium ion concentration, contact time, pH, and temperature on adsorption were evaluated. The kinetics were shown to follow the pseudo-second-order kinetic model and Elovich model, and the rate-limiting step was chemisorption. Thermodynamic studies showed that increasing the temperature promoted the adsorption of Pd(II), and the maximum uptake capacity of Fe3O4@MnO2@ZIF-67 for Pd(II) was 531.91 mg g−1. Interestingly, Fe3O4@MnO2@ZIF-67 exhibited superior selectivity for Pd(II) in the presence of Ir(IV), Pt(IV), and Rh(III). The adsorbent can be used repeatedly for selective adsorption of palladium. Even at the fifth cycle, the uptake rate of Pd(II) remained as high as 83.1%, and it showed a favorable adsorption capacity and selectivity for Pd(II) in real metallurgical wastewater. The adsorption mechanism was analyzed by SEM, FTIR, XRD, XPS, and DFT calculations, which indicated that electrostatic interactions and coordination with nitrogen-containing groups were involved. Fe3O4@MnO2@ZIF-67 is a promising adsorbent for the efficient adsorption and selective separation of palladium ions.

Tuning the isomer composition is a key to overcome the performance limits of commercial benzyltoluene as liquid organic hydrogen carrier

This work is the outcome of a three-year journey to develop a technically feasible way to overcome the limits of the benzyltoluene (H0-BT) and perhydro benzyltoluene (H12-BT) pair, recognized as an attractive liquid organic hydrogen carrier (LOHC) system. In the first attempt to synthesize and evaluate three H0-BT regioisomers, the para isomer showed faster H2 storage and release rates than the ortho and meta counterparts. This was attributed to its favorable adsorption capacity and strength on the catalyst surface. The subsequent evaluation of binary and ternary H0-/H12-BT isomeric mixtures, prepared by physical mixing the synthesized isomers, suggested that abundant amounts of para isomer in the mixture were needs to maximize the LOHC performance. Thus, a H0-BT mixture with 72 % para isomer was successfully synthesized using the zeolite H-Beta under optimized conditions, resulting in a faster kinetics of both H2 storage and release than commercial Marlotherm LH. Cycling tests on this mixture indicated that the formation of methylfluorene as a dehydrogenation byproduct was detrimental to the hydrogenation reaction. By reducing the formation of methylfluorene to a level of 3 % using a sulfur-decorated Pt/Al2O3 catalyst, a gravimetric H2 storage density of 6 wt% could be maintained for 10 cycles. Finally, a cost analysis confirmed that the isomeric composition of H0-BT in the mixture should be tuned to increase the para isomer content, while the raw materials for H0-BT synthesis are cheap. The step-by-step approach reported herein will pave the way for the development of novel aromatic LOHC systems in the near future.

Polyethyleneimine functionalized crescent-shaped microgel templated by Janus emulsion for rapid eliminating lead from water

Microgels is recognized as one of the most important functional sorbents for heavy metal removal from contaminated water. However, their simple synthesis and group-specific modifications are still challenging. Herein, polyethyleneimine (PEI) functionalized crescent-shaped microgel sorbent (CPNIPAM-AGE-PEI) was prepared for rapid eliminating Lead ions (Pb(II)) from water. CPNIPAM-AGE-PEI (diameter about 10 µm) exhibited well-defined crescent morphology with preferred orientation of cavity from DEX phase. The adsorption kinetics and isotherm data of Pb(II) on CPNIPAM-AGE-PEI demonstrate that the unique crescent-shaped structure enhanced the kinetic performance, achieving 89.52 % of the saturation adsorption capacity in the first 30 min. A favorable and monolayer adsorption capacity at 298.15 K was 52.27 mg g−1, and chemisorption based on N atoms of functionalized PEI chains may be the main adsorption mechanism. In the case of competition with other ions, CPNIPAM-AGE-PEI has excellent selective adsorption capacity for Pb(II), and the adsorption capacity remained above 87 % after five adsorption/desorption cycles.

Construction of a Novel Closed-Loop Livestock Waste Valorization Paradigm: Bridging Manure and Ammonia Gas via Phosphate-Doped Hydrochar

Sustainable livestock production plays an important role in meeting the growing global demand for animal products. Livestock manure and odor emission are regarded as the major obstacles to the low-carbon livestock farming. In response, we propose a novel loop for the valorization of livestock wastes, via bridging manure and the typical odor NH3 with P-doped hydrochar. P-doped cow manure hydrochar was facilely prepared via hydrothermal carbonization followed by H3PO4 activation. The organic composition and crystallinity of hydrochar as the precursor, depending on hydrothermal severity, significantly impacted the subsequent H3PO4 activation behavior. The activated sample with modified surface exhibited favorable NH3 adsorption capacity in the dynamic adsorption experiment. Density functional theory calculation confirmed that the P-containing group improved the NH3 adsorption efficiency as the active site. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses demonstrated the oxidation of reduced phosphorus groups during NH3 adsorption in room temperature. Phosphorus species strengthened the immobilization of NH3 on the surface via Brønsted and Lewis-type acid–base interaction. This study provided a new strategy to develop a green NH3 adsorbent from the manure-based hydrochar, supporting the further investigation on the promising solution of odor control and waste valorization in livestock farms.

Efficient adsorptive removal of fluoroquinolone antibiotics from water by alkali and bimetallic salts co-hydrothermally modified sludge biochar

Fluoroquinolones are one of most commonly used antibiotics for preventing and treating bacterial infections and their unsatisfactory removal by conventional wastewater treatment technology have aroused widespread attention. A novel adsorbent of KMSBC was the first time synthesized and tested to adsorb three typical fluoroquinolone antibiotics of CIP, NOR and OFL from water. The characterization analysis showed that KMSBC possessed the superior porous structure, abundant functional groups and greater graphitic degree. Together with kinetics, isotherms, thermodynamics and critical factors (e.g., biochar dose, reaction time/temperature, fluoroquinolone antibiotics concentration, pH, co-existing ionic strength and HA concentration) analysis suggested that pore filling, π-π conjugation, H-bonding and electrostatic interaction were the key mechanisms for fluoroquinolone antibiotics adsorption by KMSBC. KMSBC exhibited the optimum adsorption performance at pH = 5 despite the adsorbates. The maximum adsorption capacity of KMSBC for CIP, NOR and OFL were 49.9, 55.7 and 47.4 mg/g at 25 °C, respectively. Also, KMSBC exhibited the good magnetic sensitivity and stability with the leaching concentrations of Fe were far below than environmental limit (GB5749-2006) at various pH (from 3 to 12), ionic strength and HA concentrations. Additionally, KMSBC performed a stable sustainable adsorption performance in recycles by NaOH regeneration. Thus, KMSBC had the potential to be a promising adsorbent for fluoroquinolone antibiotics removal with favorable adsorption capacity, environmental security and easy regeneration performance.

Adsorption Mechanism and Electrochemical Characteristic of Methyl Blue onto Calcium Ferrite Nanosheets

A rapid combustion process was applied to prepare CaFe2O4 nanomaterials using CaBr2·xH2O and Fe(NO3)3·9H2O as raw materials and CaFe2O4 nanomaterials were characterized by SEM, TEM, VSM, XRD, and FTIR techniques. The results showed that the prepared nanomaterials had a sheet-like structure, and for larger adsorption capacity of dyes, CaFe2O4 nanosheets prepared at 700°C for 2 h with average grain size was 93.3 nm, a thickness of 8.4 nm, and the saturation magnetization of 8.15 emu/g were employed as adsorbate for the removal of methyl blue (MB). The adsorption performance of MB onto CaFe2O4 nanosheets was investigated; CaFe2O4 nanosheets displayed favorable adsorption capacity, and the adsorption conformed to the pseudo-second-order model and the Freundlich model, which demonstrated that the adsorption process of MB on CaFe2O4 nanosheets belonged to multilayer chemisorption process. When the pH value reached 3, the adsorption capacity of MB by CaFe2O4 nanosheets kept maximum value of 478.07 mg/g; and after 5 regenerations, the removal efficiency of MB was reduced to 59.06% of the first time. The electrochemical behavior of MB onto the nanosheets was evaluated through CV in conjunction with EIS. The CaFe2O4 nanosheets revealed a promising prospect for the adsorption of dyes.

Facile fabrication of the porous adsorbent from natural plant Angelica Sinensis stabilized liquid foam for dye removal

Porous materials as emerging high-efficiency adsorbents have attracted increasing attention in recent years, due to the high specific surface area, fast adsorption rate, favorable adsorption capacity to heavy metal, dyes, and other pollutants, etc. Among various approaches, the foam template method with the advantage of flexible operation and controllable pores structure is proposed to prepare net type of porous adsorbents with superior adsorption capacity and rapid adsorption rate. In this process, natural plant Angelica Sinensis (AS) was treated with a simple alkaline-heat process, and the resultant product was used firstly to prepare foam with high stability, and the positive effect of the cellulose dissociation and the conversion of ligustilide into amphiphilic moleculars on improving the stability of Pickering foam was revealed. The liquid foam can serve as pore-foaming template and precursor of polymerization for synthesizing porous adsorbent by one-step integrated process of free radical polymerization and silane hydrolysis. The porous adsorbent showed the sufficient porous structure and excellent adsorption performance for cationic dye, with maximum adsorption capacities of 386.13 mg g-1 and 284.20 mg g-1 for methyl violet (MV) and malachite green (MG). In a word, the novel approach can provide an important reference for green synthesis of high stable foam and the superporous material, and the adsorbent showed great application potential in the field of water treatment.

Synthesis of zero-valent iron/biochar by carbothermal reduction from wood waste and iron mud for removing rhodamine B.

This study proposes a new process to synthesize zero-valent iron/biochar (Fe0-BC) by carbothermal reduction using wood waste and iron mud as raw materials under different temperature. The characterization results showed that the Fe0-BC synthesized at 1200 °C (Fe0-BC-1200) possessed favorable adsorption capacity with the specific surface area of 103.18 m2/g and that the zero-valent iron (Fe0) particles were uniformly dispersed on the biochar surface. The removal efficiency of rhodamine B (RB) was determined to evaluate the performance of the prepared Fe0-BC. Fe0-BC-1200 presented the best performance on RB removal, which mainly ascribes to that more Fe0 particles generated at higher temperature. The equilibrium adsorption capacity reached 49.93 mg/g when the initial RB concentration and the Fe0-BC-1200 dosage were 100 mg/L and 2 g/L, respectively, and the pseudo-second-order model was suitable to fit the removal experimental data. LCMC and XRD analyses revealed that the removal mechanism included the physical adsorption of biochar and the redox reaction of Fe0. Moreover, copper existing in the iron mud was also reduced to Cu0, which was beneficial to catalyze the oxidation of iron; the degradation of RB was promoted at the same time.

Grafting of regenerated cellulose films with fibrous polymer and modified into phosphate and sulfate groups: Application for removal of a model azo-dye

Regenerated cellulose films (RCF) were functionalized with bromoacetyl bromide as atom transfer radical polymerization (ATRP) initiator. Then, poly(glycidyl methacrylate), p(GMA), as a functional polymer was grafted via surface initiated ATRP (SI-ATRP) on the RCF. The polymer grafted RCF was modified into phosphate [i.e.,(RCF-g-p(GMA)-PO3H2)] and sulfate [i.e.,(RCF-g-p(GMA)-SO3H)] groups using H3PO4 and H2SO4, respectively. The synthesized composite adsorbents were characterized using FTIR, SEM and analytical methods to evaluate the structural and morphological characteristics of the modified cellulose based films. The effectiveness of both cation exchange films [(RCF-g-p(GMA)-PO3H2) and (RCF-g-p(GMA)-SO3H)] for the removal and recovery of Chlorazole Black E (CBE) dye was investigated from aqueous solutions. The adsorbent dosage, pH, ionic strength, initial concentration of dye, and contact time were studied to optimize the conditions for maximum adsorption. The adsorption process was pH dependent, shows maximum removal at pH 5.5 and 2.0 for RCF-g-p(GMA)-PO3H2 and RCF-g-p(GMA)-SO3H, respectively. The maximum adsorption capacities were found to be 165.7 and 268.6 mg/g for the RCF-g-p(GMA)-PO3H2 and RCF-g-p(GMA)-SO3H, respectively. Kinetic studies showed that pseudo-second-order kinetic model described well the kinetics of adsorption of the CBE dye. Adsorption equilibrium data were correlated with the Langmuir, and Freundlich isotherm models. Adsorption/desorption for 10 cycles showed the possibility of repeated use of modified RCF for removal and recovery of the dye from aqueous solutions. These presented both cationic adsorbents had several operational advantages for the dye removal from aqueous medium indicating that they are talented materials to be used in wastewater treatment. Finally, the RCF-g-p(GMA)-SO3H adsorbent with strong acidic groups can be utilized for the removal of basic dyes from industrial wastewaters in sight of its favorable high adsorption capacity.

Fast Track to Acetate-Based Ionic Liquids: Preparation, Properties and Application in Energy and Petrochemical Fields.

Acetate-based ionic liquids (AcILs), as a kind of typical carboxylate-based ILs, display excellent structure tunability, non-volatility, good solubility to biomass, and favorable adsorption capacity, etc. These unique characteristics of AcILs make them important candidates for a range of applications in the field of energy and in the petrochemical industry. This paper intends to provide a comprehensive overview of recent advances in AcILs, including pure AcILs, AcIL-based multi-solvents, and AcIL-based composites, etc. Preparation methods, with one- and two-step synthesis, are reviewed. The relationship between properties and temperature is discussed, and some physical and thermodynamic properties of different AcILs are summarized and further calculated. The applications of AcILs in the fields of biomass processing, organic synthesis, separation, electrochemistry, and other fields are reviewed based on their prominent properties. Thereinto, the dual functions of AcILs as solvents and activators for biomass dissolution are discussed, and the roles of AcILs as catalysts and reaction mediums in clean organic synthesis are highlighted. Meanwhile, the reaction mechanisms of AcILs with acid gases are posed by means of molecular simulation and experimental characterization. Moreover, AcILs as electrolytes for zinc batteries, supercapacitors, and electrodeposition are particularly introduced. Finally, the future research challenges and prospects of AcILs are presented.

Ionic liquid modification of metal-organic framework endows high selectivity for phosphoproteins adsorption

Zr-based metal-organic framework, UiO-66-NH2, provides favorable adsorption capacity to phosphoproteins, however, it exhibits obvious nonspecific adsorption to other proteins. In the present work, we report a facile strategy to reduce the nonspecific adsorption of nonphosphoproteins by modifying UiO-66-NH2 with imidazolium ionic liquids (ILs). With respect to bare UiO-66-NH2, the modified counterpart, UiO@IL, exhibits much improved selectivity to phosphoproteins while maintains comparable adsorption performance. The surface of UiO@IL presents a strong hydrophilicity due to the modification of ILs. Hydrophobic and electrostatic interaction between the absorbent and nonphosphoprotein is significantly reduced. In addition, the interaction between imidazole group of ILs moiety and phosphate group in phosphoprotein ensures the favorable adsorption capacity of UiO@IL for phosphoproteins. Anionic moieties of ILs, i.e., Cl−, Br−, BF4−, CF3SO3−, play negligible effect in the adsorption process. As a representative, phosphoprotein β-casein (β-ca) is selectively enriched at a mass ratio of BSA:β-ca = 100:1. UiO@IL was further applied for the selective enrichment of phosphoprotein in milk.