RESUMEN
The development of novel materials for electrodes with high energy densities is essential to the advancement of energy storage technologies. In this study, N-doped layered porous carbon with ZIF-67-derived binary CoFe2O4-Fe particles was successfully fabricated by the pyrolysis of an Fe-based chitosan (CS) hydrogel mixed with ZIF-67 particles. Various characterization techniques were employed to assess the performance of the prepared porous CoFe2O4-Fe@NC composite. This composite exhibits excellent performance owing to the effective combination of multivalent CoFe2O4-Fe particles derived from ZIF-67 with N-doped porous carbon substances with a high surface area, which helps to accelerate ion and charge transfer. The specific capacitance of the CoFe2O4-Fe@NC composite carbonized at 700 °C reached 3960.9F/g at 1 A/g. When this composite is combined with activated carbon (AC) to construct an asymmetric supercapacitor (ASC), a density of energy of up to 84.9 W h kg-1 is attained at a power capacity of 291.6 W kg-1. Moreover, this composite maintained a capacitance retention of up to 94.9 % after 10,000 cycles. This work offers new perspectives on high-performance supercapacitors and their applications.
RESUMEN
An emerging carbothermal shock method is an ultra-convenient strategy for synthesizing high-entropy alloys (HEAs), in which the intelligent combination of carbon support and HEAs can be serve as a decisive factor for interpreting the trade-off relationship between conductive gene and dielectric gene. However, the feedback mechanism of HEAs ordering degree on electromagnetic (EM) response in 2-18 GHz has not been comprehensively demystified. Herein, while lignin-based carbon fiber paper (L-CFP) as carbon support, L-CFP/FeCoNiCuZn-X with is prepared by carbothermal shock method. The reflection loss of -82.6 dB with thickness of 1.31 mm is achieved by means of pointing electron enrichment within L-CFP/FeCoNiCuZn HEAs heterointerfaces verified by theoretical calculations. Simultaneously, low-frequency evolution with high-intensity and broadband EM response relies on a "sacrificing" strategy achieved by construction of polymorphic L-CFP/semi-disordered-HEAs heterointerfaces. The practicality of L-CFP/FeCoNiCuZn-X in complex environments is given prominence to thermal conductivity, hydrophobicity, and electrocatalytic property. This work is of great significance for insightful mechanism analysis of HEAs in the application of electromagnetic wave absorption.
RESUMEN
Recyclable, non-toxic, and degradable biological substrates contribute significantly to super-wetting surfaces. In this work, we prepared magnetic micro-nano super-hydrophobic surfaces through a robust solution with magnetic modified lignin particles as the supporting structure. A novel PDMS (polydimethylsiloxane)/magnetic lignin particle (lignin@Fe3O4)/PDA sponge composite was fabricated. Through dopamine (DA) self-polymerization, covalent deposition of magnetic lignin (ML), and PDMS silane modification, the magnetic super-hydrophobic polyurethane sponge composite (Sponge-P) was synthesized so that the Fe3O4 nanoscale microspheres wrapped with microscale lignin magnetic particles adhered to the sponge surface tighter and were barely dislodged. The as-prepared Sponge-P displayed excellent flexibility and a water contact angle of up to 152.2°. The super-hydrophobic sponge prepared with the proposed method was acid-base stable (pH = 2-12), self-cleaning, and suitable for high-salinity seawater. The magnetic super-hydrophobic sponge has good oil-water separation ability and can absorb 43 times its own weight of oil. In the meantime, due to the introduction of magnetic materials into lignin, we not only constructed micro-nanostructures to improve the surface super-hydrophobicity, but also made Sponge-P have the function of magnetic recovery, which has a unique advantage in treating oily wastewater.
Asunto(s)
Vendajes , Lignina , Fenómenos Físicos , Dopamina , Fenómenos MagnéticosRESUMEN
The rational design and synthesis of advanced electrode materials are significant for the applications of supercapacitors. Ferroferric oxide (Fe3O4), with its high theoretical capacitance is a renowned cathode material. Nevertheless, its low electronic conductivity and poor cycling stability during a long-term charge/discharge process limit its large-scale applications. In this work, the precise modulation of multiple components was reported to enhance electrochemical performance. The ternary heterostructures were fabricated by wrapping ultrathin nickel hydroxide (Ni(OH)2) nanosheets on the surfaces of Fe3O4 nanoparticles-loaded on sodium carboxymethyl cellulose (CMC)-derived porous carbon, named as C/Fe3O4@Ni(OH)2. Due to the large specific surface area and excellent conductivity of CMC-derived porous carbon and the abundant reaction sites of Ni(OH)2 nanosheets, the optimized C/Fe3O4@Ni(OH)2-1.0 sample exhibited the highest specific capacitance of 3072F g-1 at a current density of 0.5 A g-1. Furthermore, the assembled asymmetric supercapacitor (ASC) with activated carbon and C/Fe3O4@Ni(OH)2-1.0 as the negative and positive electrodes, respectively, showed an energy density of 123 W h kg-1 at 381 W kg-1, and a long-life stability with an excellent capacitance retention of 90.04 % after 10,000 cycles. The route for preparing composite electrode materials proposed in this work provides a reference for realizing high-performance energy storage devices.
RESUMEN
Copper oxide (CuO) and copper (Cu) have been viewed as the prospective pseudocapacitive electrode materials for supercapacitors. Nevertheless, the poor electron transfer capacity, loading amount, and cycling stability limit their wide applications, which can be addressed by developing the CuO based heterojunction on conductive carbons. Here, a CuO/Cu@C comprising CuO/Cu nanoflowers and chitosan-derived N-doped porous carbon was compounded by simple mechanical mixing, freeze-drying, and carbonization. The composite heated at 700 °C exhibited a high specific capacitance of 2479F/g at 0.5 A/g and excellent cycling stability with capacitance retention of 82.43 % after 10 000 charge-discharge cycles. In addition, the asymmetric supercapacitor (ASC), i.e., CuO/Cu@C-700//AC assembled by CuO/Cu@C (as a positive electrode) and activated carbon (AC, as a negative electrode) displayed a great energy density of 76.87 W h kg-1 at 374.5 W kg-1 and kept as high as 25.83 W h kg-1 even at 14998 W kg-1. Our work provides a new pathway to preparing transition metal oxide-based electrode materials with distinguished electrochemical performances.
RESUMEN
The development of g-C3N4-based photocatalysts with abundant active sites is of great significance for photocatalytic reactions. Herein, a smart and robust strategy was presented to fabricate three-dimensional (3D) g-C3N4 nanosheet-coated alginate-based hierarchical porous carbon (g-C3N4@HPC), including coating melamine on calcium alginate (CA) hydrogel beads, freeze-drying hydrogel beads as well as pyrolysis at high temperatures. The resulting photocatalyst possessed a significantly high surface area and a large amount of interconnected macropores compared with porous carbon without the melamine coating. The unique structural features could effectively inhibit the curling and agglomeration of g-C3N4 nanosheets, provide abundant photocatalytic active sites, and promote mass diffusion. Therefore, the g-C3N4@HPC composite exhibited remarkable photocatalytic activity and outstanding stability toward the photoreduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 under natural sunlight and simulated visible-light irradiation (λ > 420 nm) using a 300 W xenon lamp. Moreover, the mechanism toward the photocatalytic reaction was extensively studied by quenching experiments and electron spin resonance (ESR) experiments. The results showed that active hydrogen species were able to be achieved by following a dual-channel pathway in the NaBH4 system, which included photocatalytic reduction of H+ ions and photocatalytic oxidation of BH4- ions. This work not only opens up a new way to design efficient photocatalysts for various reactions but also provides a reference for an in-depth study of the photoreduction mechanism.
RESUMEN
Designing interfacial coating with tailored characteristics is a crucial step in regulating the wetting properties of oil/water separation materials; however, the controllable fabrication of multifunctional layer with long-term durability in harsh environments remains challenging. Fabrication of raised dots based on magnetic Fe3O4 particles on micro-nanometer units, inspired by mussel chemistry, under the adhesion behavior of dopamine (DA) self-polymerization covalent deposition of Fe3O4 particles and hydrophobic polydimethylsiloxane (PDMS) modification to synthesize magnetic superhydrophobic cotton composites (Cotton-P). Due to the unique magnetic and superhydrophobic surface composition, the synthetic Cotton-P possesses superhydrophobic (155.4°) and magnetic properties and still exhibits these excellent properties after 10 cycles. In addition, the hydrophobicity of magnetic monolithic cotton is virtually unaffected in harsh environments. The chemical/thermal stability of the Cotton-P composite is improved due to the rigid silane coating on the skeleton. Moreover, the Cotton-P revealed excellent oil/water separation efficiency of over 98 % after 10 cycles. Based on these outstanding properties, Cotton-P has the potential to develop in the treatment of oil-water mixtures.
Asunto(s)
Silanos , Purificación del Agua , Dimetilpolisiloxanos , Dopamina , Interacciones Hidrofóbicas e Hidrofílicas , Aceites/químicaRESUMEN
A separable spherical bio-adsorbent (CMC-Cr) was prepared for capturing heavy metal ions by simple coordination and cross-linking between targeted ions of Cr3+ and carboxymethyl cellulose (CMC). A simple alternation of the CMC incorporation allowed the interconnected networks within the microspheres of preformed solid CMC to be adjusted. The excellent network structure could achieve the maximum collision between the adsorbent and the heavy metal cations in the wastewater. Through investigations, CMC-Cr-2 beads were determined as the optimal adsorbent. The adsorption performance of novel materials was evaluated by examining their adsorption behavior on Pb(II) and Co(II) under both static and dynamic conditions. The results showed that the adsorption behavior of CMC-Cr-2 beads on both two heavy metal cations could be fully reflected by the Freundlich model. Under the theoretical conditions, the maximum adsorption capacities were 97.26 and 144.74 mg/g. The kinetic results for the adsorption of two heavy metal cations on CMC-Cr-2 beads were consistent with the Pseudo-second-order kinetic model. Moreover, the correlation coefficient of the Thomas model was significant in the dynamic adsorption performance tests. Five regeneration cycle studies were successfully carried out on CMC-Cr-2 beads to evaluate reusability and stability. The applicability of CMC-Cr-2 beads in authentic aqueous solutions (both the single and binary pollutant systems) was also studied, and the results indicated that CMC-Cr-2 beads had a high potential for practical implementation. Furthermore, by analyzing the surface interactions of two heavy metal cations with the CMC-Cr-2 beads based on FTIR and XPS characterization, a basic understanding of the interaction between bio-sorbents and pollutants in wastewater can be obtained.
Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Adsorción , Carboximetilcelulosa de Sodio/química , Cationes , Concentración de Iones de Hidrógeno , Iones , Cinética , Aguas ResidualesRESUMEN
The preparation of biomass-derived carbon electrode materials with abundant active sites is suitable for development of energy-storage systems with high energy and power densities. Herein, a hybrid material consisting of highly-dispersed nickel ferrite nanoparticle on 3D hierarchical carboxymethyl cellulose-derived porous carbon (NiFe2O4/CPC) was prepared by simple annealing treatment. The synergistic effects of NiFe2O4 species with multiple oxidation states and 3D porous carbon with a large specific surface area offered abundant active centers, fast electron/ion transport, and robust structural stability, thereby showing the excellent performance of the electrochemical capacitor. The best performing sample (NiFe2O4/CPC-800) exhibited a superior capacitance of 2894F g-1 at a current density of 0.5 A g-1. Encouragingly, an asymmetric supercapacitor with NiFe2O4/CPC-800 as a positive electrode and activated carbon as a negative electrode delivered a high energy density of 135.2 W h kg-1 along with an improved power density of 10.04 kW kg-1. Meanwhile, the superior cycling stability of 90.2% over 10,000 cycles at 5 A g-1 was achieved. Overall, the presented work offers a guideline for the design and preparation of advanced electrode materials for energy-storage systems.
Asunto(s)
Carboximetilcelulosa de Sodio , Nanopartículas , Celulosa/química , Compuestos Férricos , Níquel , PorosidadRESUMEN
Recently, biochar-related phosphate sorbents have been extensively investigated and achieved significant progress; however, there is still much room for enhancement on capturing performance and recovery of powdery ones after sorption. Herein, a new kind of adsorbent, in which biochar/Mg-Al spinel encapsulated in carboxymethyl cellulose-La hydrogels with cationic polymeric layers, was fabricated, aiming for integrating multi-advantages of each component for enhanced phosphate capture. Batch static experiments were correlated to the phosphate adsorption performance of the adsorbent. The maximum phosphate adsorption capacity of the adsorbent was 89.65 mg P/g at pH = 3. The Langmuir isotherm model and the pseudo-second-order kinetic model fitted well with the adsorption behavior of the adsorbent. More importantly, this composite adsorbent that integrated with biochar, Mg-Al spinel, cationic polymeric components exhibited favorable selectivity over coexisting anions (Cl-, SO42-, HCO3- and NO3-) and performed good reusability after five consecutive cycles. By virtue of the bead-like feature, fixed-bed column experiments demonstrated that the Thomas model fitted the breakthrough curves well under varied experimental conditions. The adsorption mechanism of phosphate on the designed composite adsorbent with multi-components could be described as the electrostatic attraction, ligand exchange and inner-sphere complexation, which might account for the efficient phosphate capturing performance.
Asunto(s)
Fosfatos , Contaminantes Químicos del Agua , Adsorción , Óxido de Aluminio , Carboximetilcelulosa de Sodio , Carbón Orgánico , Hidrogeles , Cinética , Óxido de Magnesio , Contaminantes Químicos del Agua/análisisRESUMEN
Here, we have developed a novel bilayer hollow amphiphilic biosorbent (BHAB-3) with large adsorption capacity, rapid adsorption kinetics, and cost-effective for the removal of Cr(VI) and Cu(II) from aqueous solutions. The synthesis was based on the clever use of freeze-drying to fix the structure, secondary modification of the carboxymethyl cellulose microspheres with polyethyleneimine and cross-linking by glutaraldehyde. The consequences of pH, initial concentration, contact time and temperature on adsorption were investigated. The Langmuir model fits showed that the maximum adsorption capacities of the two target heavy metal ions reached 835.91 and 294.79 mg/g, respectively. Moreover, BHAB-3 was characterized by SEM, FT-IR, TGA, and XPS synergistically, showing that it exhibits a strong complexation ability for Cu(II) and a strong electrostatic effect for Cr(VI). Adsorption and desorption experiments showed only a slight decrease in the adsorption capacity of the BHAB-3 for Cr(VI) and Cu(II) ions after 5 and 26 cycles, respectively. Given the excellent properties of this adsorbent, it is a promising candidate for heavy metal ion removal.
Asunto(s)
Contaminantes Químicos del Agua , Cationes , Cromo , Concentración de Iones de Hidrógeno , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Novel millimeter hollow microspheres were fabricated from carboxymethyl cellulose microspheres and polyethyleneimine using glutaraldehyde as a crosslinking agent. The hollow microspheres prepared with different polyethyleneimine usages and different polyethyleneimine treatment time were investigated deeply and characterized via SEM-EDX, FT-IR, and BET surface area analysis. It was shown that polyethyleneimine could break the coordination bonds between the carboxyl and Al (III) in carboxymethyl cellulose microspheres, leading to the formation of hollow structures. Most importantly, the usage and treatment time of polyethyleneimine can distinctly tailor the structure of the carboxymethyl cellulose microspheres, resulting in the formation of different hollow microspheres with varied shell thickness and size. Most importantly, we found that the prepared hollow microspheres have excellent adsorption performance toward targeted methyl blue under testing conditions. By virtue of the large accessible amount of -NH2 groups and its unique hollow structure, this type of millimeter hollow microspheres have broad application prospects in the treatment of emerging contaminants in wastewater.
Asunto(s)
Carboximetilcelulosa de Sodio/química , Colorantes/aislamiento & purificación , Microesferas , Adsorción , Cinética , Nitrógeno/química , Polietileneimina/química , Porosidad , Espectroscopía Infrarroja por Transformada de Fourier , TemperaturaRESUMEN
Manufacturing heteroatom-doped porous C with controllable N species is an important issue for supercapacitors. Herein, we report a low-cost and simplified strategy for synthesizing B,N-codoped porous C (BNPC) by a freeze-drying chitosan-boric acid aerogel beads and subsequent carbonization treatment. The BNPC samples were studied using various characterization technologies. The introduction of boric acid to chitosan successfully induced the formation of B,N-codoped C with a well-developed 3D interconnected porous structure. The B doping had a significant impact on the distribution of N species in the samples. Moreover, the good wettability of the sample resulting from B doping is favorable for electrolyte diffusion and ion transport. As a consequence, the optimal BNPC sample showed an excellent specific capacitance of 240 F g-1 at 0.5 A g-1 and an outstanding capacitance retention of 95.1% after 10000 cycles at 5 A g-1. An assembled symmetrical supercapacitor displayed an energy density of 11.4 Wh kg-1 at a power density of 250 W kg-1. The proposed work provides a simple and effective method to obtain B,N-codoped C-based materials with high electrochemical performance.
RESUMEN
Phosphorus (P) has brought a series of environmental problems while benefiting mankind. To reclaim phosphorus from wastewater efficiently and conveniently, a novel magnetic adsorbent with aminated lignin/CeO2/Fe3O4 composites (AL-NH2@Fe3O4-Ce) possessing a high affinity to phosphate and easily separated from aqueous solutions was developed in this work. The characterization results revealed that Fe and Ce elements have been doped into the aminated lignin successfully. Batch experiment results convinced that the maximum phosphate adsorption capacity of AL-NH2@Fe3O4-Ce was 183.72 mg P/g at pH = 3, which was roughly 4.5 times greater than aminated lignin and 8.5 times greater than cerium oxide, respectively. The adsorption isotherm was fitted well by the Langmuir model, and the adsorption kinetics was in line with the pseudo-second-order model. The adsorption thermodynamics indicated the adsorption process was spontaneous and naturally exothermic. Additionally, AL-NH2@Fe3O4-Ce exhibited high selectivity towards phosphate over common coexisting anions (Cl-, NO3-, HCO3-, SO42- and F-). After five consecutive cycles, the adsorption performance of AL-NH2@Fe3O4-Ce decreased by only 16% compared with the fresh adsorbent, indicating that AL-NH2@Fe3O4-Ce exhibited excellent recycling ability. The results of XPS analysis and batch experiments showed that the possible mechanisms were electrostatic attraction and inner-sphere complexation. The tailored interfacial chemistry affinity to phosphate as well as endowed magnetic property reveled AL-NH2@Fe3O4-Ce could be adopted as an up and coming adsorbent in phosphate removal process.
Asunto(s)
Lignina , Fosfatos , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Fenómenos Magnéticos , Aguas ResidualesRESUMEN
Noble metal-based catalytic material with maximum utilization is of prime attraction for conserving rare metal resources. Herein, highly dispersion Ni nanoparticles (NPs)-modified N-doped mesoporous carbon material (Ni-N@C) was fabricated by pyrolysis of Ni2+/Histidine cross-linked alginate hydrogels. In a step forward, the obtained Ni-N@C nanocatalyst was treated by the solution of Pd2+, and tiny amount of Pd NPs were deposited on the surface of Ni via the reducibility of Ni to achieve the high dispersion of precious metals material. In the degradation of highly-concentration p-nitrophenol, the catalyst presents excellent performance which could completely degrade pollutants within a very short period. It was demonstrated that pre-embedded Ni NPs could not only increase the efficiency of Pd NPs but also endow the facile separation characteristic to the catalyst. Besides, the catalyst maintained favorable catalytic capacity even after five reaction cycles. In brief, this work may provide novel guidance for the maximum utilization of noble metal-modified mesoporous N-doped carbon-supported catalysts in practical applications of industrial and the treatment highly-concentration p-nitrophenol.
Asunto(s)
Nanopartículas del Metal/química , Níquel/química , Nitrofenoles/química , Paladio/química , Contaminantes Químicos del Agua/química , Alginatos/química , Carbono/química , Catálisis , Cationes Bivalentes , Humanos , Hidrogeles/química , Nanopartículas del Metal/ultraestructura , Oxidación-Reducción , Porosidad , Aguas Residuales/químicaRESUMEN
Superior mechanical properties, high adsorption capacity, and excellent regeneration property are crucial design criterions to develop a new-type aerogel for adsorptive applications towards heavy metal removal from water. Herein, chitosan and melamine not only introduced abundant functional groups to increase adsorbing sites for lead ions, but also reinforced the three-dimensional network skeleton structure of absorbents to improve the service life in adsorption applications. As-fabricated alginate/melamine/chitosan aerogel can extract Pb (II) from aqueous solution efficiently, i.e., the optimum adsorption quantity of 1331.6 mg/g at pH 5.5, which exhibited excellent and selective adsorption capacity for Pb (II) against the competition of coexisting divalent metal ions. More importantly, alginate/melamine/chitosan aerogel could be regenerated using dilute acidic solution and recovered well after eight adsorption-desorption cycles. This work might offer a new idea for design and preparation of biomass-based aerogel sorbents with promising prospect in the remediation of Pb (II)-contaminated wastewater.
Asunto(s)
Alginatos/química , Quitosano/química , Iones , Plomo/química , Triazinas/química , Adsorción , Materiales Biocompatibles/química , Biomasa , Geles , Concentración de Iones de Hidrógeno , Cinética , Metales , Metales Pesados , Sodio/química , Espectroscopía Infrarroja por Transformada de Fourier , Estrés Mecánico , Temperatura , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Purificación del AguaRESUMEN
The multistage reclamation of materials has made contributions to sustainable development, but further progress is still sought after. In this work, functionalized seaweed-based composites were successfully prepared and utilized in multiple stages. Specifically, Co2+-containing alginate hydrogels (CHB-Co2+) prepared by sol-gel self-assembly and adsorption method using interior/exterior co-functionalized calcium alginate as raw materials were utilized for efficient reduction of p-nitrophenol. After coupling with freeze-drying and carbonization procedures, a high-performance Co/N co-doped carbonaceous microwave absorber was obtained and investigated in detail. By virtue of unique 3D interconnected network, heterogeneous interfaces and doped heteroatom N species, by which endowing the absorber with optimal impedance matching and attenuation ability, as-fabricated NC-Co-700 exhibited prominent microwave absorption performance with -54.2 dB of RLmin at 6.4 GHz and 5.3 GHz of maximum absorption bandwidth (from 12.7 to 18.0 GHz). Additionally, in view of the dielectric loss and magnetic loss caused by the synergy effect among the functional components, the underlying absorption mechanism was proposed. This work provided a novel idea for designing biomass-based functional materials and simultaneously achieved economic benefits through the rational utilization of other products in the preparation process.
Asunto(s)
Alginatos/química , Cobalto/química , Hidrogeles/química , Microondas , Absorción de Radiación , Catálisis , Nitrofenoles/química , Oxidación-Reducción , Algas Marinas/químicaRESUMEN
Heavy metal ions pollution is a terrible issue that needs to be efficiently treated as a matter of priority to construct our sustainable society. However, the easy-to-handling of high-performance biomass-derived sorbents with fascinating features like high sorption capacity, favorable separation and recycling remain challenging. Herein, the development of a novel bead-like adsorbent with above features, that is, Al(III)-assembled carboxymethyl cellulose beads were used for the removal of Pb(II), Ni(II) and Co(II) from aqueous solution. Characterization methods like FT-IR, SEM, XPS and TGA were employed to confirm its physicochemical properties. Removal of the three heavy metal ions at different pH values, initial concentration and contact time were discussed at batch adsorption experiments. Meanwhile, regeneration was also discussed deeply. The results revealed that the adsorption capacity of the sorbents for three heavy metals increases with increasing pH and the initial concentration. The adsorption isotherm could be described well by the Freundlich model, and the maximum adsorption capacity for Pb(II), Ni(II) and Co(II) were 550, 620 and 760 mg/g, respectively. Kinetics study indicated that the Pseudo-second-order model described the best correlation with experimental data, this suggested that the complexation may participated in the adsorption process. More significantly, this type of bead-like adsorbents displayed excellent reusability after four sequential cycles.
Asunto(s)
Carboximetilcelulosa de Sodio/química , Metales Pesados/aislamiento & purificación , Purificación del Agua/métodos , Adsorción , Aluminio/química , Celulosa/química , Criogeles/química , Concentración de Iones de Hidrógeno , Iones , Cinética , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Temperatura , Termodinámica , Agua/química , Contaminantes Químicos del Agua/químicaRESUMEN
In order to alleviate the environmental problems caused by excessive discharge of phosphate, an environmental friendly and highly efficient bio-sorbent (SA-La@PEI) for phosphate was fabricated by combing strategies of sorption affinity component mediated and poly(ethylenimine) surface engineering of alginate beads. Various characterization methods like SEM, FTIR, XRD and XPS were adopted to examine the morphology and functional group composition of SA-La@PEI. Through detailed tests, SA-La@PEI exhibited excellent adsorption performance of 121.2 mg/g, which was better than most published materials. More importantly, the outstanding phosphate selectivity of SA-La@PEI was exposed when NO3-, HCO3-, SO42- and Cl- were added to the phosphate solution. Considering the integrated components in composites, both chemical precipitation and electrostatic attraction can be considered as the dominant mechanisms of phosphate adsorption. Totally, as-prepared SA-La@PEI beads might be a promising sorbent for the decontamination of excessive phosphate because of its low-cost, excellent adsorption performance and mechanical strength.
Asunto(s)
Alginatos/química , Aniones/química , Lantano/química , Fosfatos/química , Contaminantes Químicos del Agua/química , Adsorción , Precipitación Química , Concentración de Iones de Hidrógeno , Cinética , Microscopía Electrónica de Rastreo , Espectroscopía de Fotoelectrones , Polietileneimina/química , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad Estática , Difracción de Rayos XRESUMEN
Designing desirable adsorbent for highly efficient removal of heavy metal ions is of practical significance, given the cost-effectiveness, environmental benign, natural abundance and easy-handling collection features. Herein, a bead-like adsorbent with high adsorption capacity was prepared by modifying alginate beads using polyacrylate with high density of carboxyl groups. The developed alginate/polyacrylate beads were collaboratively characterized by FT-IR, TGA, SEM, XPS, etc., and various adsorption conditions were tested including the pH of the solution, contact time and the initial concentration. The experimental data were fitted well by the Freundlich isotherm model, and the maximum adsorption capacity was obtained from the Langmuir model was 611.0 mg/g, and adsorption process followed the Pseudo-second-order kinetic model. The adsorption mechanisms conformed to multi-layer adsorption, and mainly dominated by chemical interactions. The bead-like adsorbent exhibited excellent reusability after eight sequential cycles and displayed higher adsorption capacity towards lead ions. This type of adsorbent might possess promising role in treating heavy metals from water by virtue of degradable, cost-effective component and high adsorption efficiency.