Synergistic Effect Of Adsorption Research Articles

Synergistic adsorption and photocatalytic degradation of tetracycline using a Z-scheme kaolin/g-C3N4/MoO3 nanocomposite: A sustainable approach for water treatment

This research focuses on the synthesis and application of a novel kaolin-supported g-C3N4/MoO3 nanocomposite for the degradation of tetracycline, an important antibiotic contaminant in water systems. The nanocomposite was prepared through a facile and environmentally friendly approach, leveraging the adsorption and photocatalytic properties of kaolin, g-C3N4 and MoO3 nanoparticles, respectively. Comprehensive characterization of the nanocomposite was conducted using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and optical spectra. The surface parameters were studied using N2 adsorption-desorption isotherm. The elemental composition was studied using X-ray photoelectron spectroscopy. The efficiency of the developed nanocomposite in tetracycline degradation was evaluated and the results revealed an efficient tetracycline degradation exhibiting the synergistic effects of adsorption and photocatalytic degradation in the removal process. The tetracycline degradation was achieved in 60 min. Kinetic studies and thermodynamic analyses provided insights into the degradation mechanism, suggesting potential applications for the nanocomposite in wastewater treatment. Additionally, the recyclability and stability of the nanocomposite were investigated, demonstrating its potential for sustainable and long-term application in water treatment.

Interfacial self-assembled of covalent organic framework onto MXenes for efficient enrichment and recovery of Au(III) and Pd(II) from aqueous solution

Recovery of precious metal ions in wastewater could not only improve resource utilization, but also could reduce environmental pollution. Herein, a composite of TpPa@Nb2C was constructed by an interfacial self-assembled method and explored the synergistic adsorption effects for precious metals. The structure and morphology of the composites were analyzed by advanced characterization techniques, followed by parametric analysis of Au(III)/Pd(II) adsorption from the simulated wastewater. The results showed that the grafting of COFs with abundant reducing active sites on the MXenes could significantly improve the selectivity and adsorption capacity. Meanwhile, the interaction was found as monolayer way and controlled by chemistry process, and the maximum equilibrium Au(III) and Pd(II) uptake reached up to 910.1 and 386.2 mg/g, respectively. The competitive adsorption study showed that the co-existence of impurities had little effect on the removal rate. The mechanism analysis demonstrated that the precious metal ions were reduced to elemental gold/palladium on the network of TpPa@Nb2C, and they got three electrons or two electrons from the hydroxyl groups through redox reaction, respectively. Thus, this study provided an excellent material for enrichment and recovery of precious metals in waste liquid and the treatment of e-waste.

MXene/ZnS/chitosan-cellulose composite with Schottky heterostructure for efficient removal of anionic dyes by synergistic effect of adsorption and photocatalytic degradation

Nowadays, dye water pollution is becoming increasingly severe. Composite of MXene, ZnS, and chitosan-cellulose material (MX/ZnS/CC) was developed to remove anionic dyes through the synergistic effect of adsorption and photocatalytic degradation. MXene was introduced as the cocatalyst to form Schottky heterostructure with ZnS for improving the separation efficiency of photocarriers and photocatalytic performance. Chitosan-cellulose material mainly served as the dye adsorbent, while also could improve material stability and assist in generation of free radicals for dye degradation. The physics and chemistry properties of MX/ZnS/CC composite were systematically inspected through various characterizations. MX/ZnS/CC composite exhibited good adsorption ability to anionic dyes with adsorption capacity up to 1.29 g/g, and excellent synergistic effects of adsorption and photodegradation with synergistic removal capacity up to 5.63 g/g. MX/ZnS/CC composite performed higher synergistic removal ability and better optical and electrical properties than pure MXene, ZnS, chitosan-cellulose material, and MXene/ZnS. After compounding, the synergistic removal percentage of dyes increased by a maximum of 309 %. MX/ZnS/CC composite mainly adsorbs anionic dyes through electrostatic interactions and catalyzes the generation of •O2−, h+, and •OH to degrade dyes, which has been successfully used to remove anionic dyes from environmental water, achieving a 100 % removal of 50 mg/L dye.

In situ synthesis of three-dimensional flower-like TiO2/WO3 heterojunction: Enhanced visible photocatalytic properties and theoretical calculations

The construction of heterojunction photocatalysts is an excellent strategy for treating wastewater. Herein, a three-dimensional nanoflower-like TiO2/WO3 heterojunction photocatalyst was synthesized in situ on the surface of pure Ti substrate by plasma electrolyte oxidation (PEO) combined with a subsequent process, and the abundant network topology and lattice defects improved the adsorption performance of the photocatalyst. The construction of Z-scheme heterojunction not only promotes the separation of photogenerated carriers, but also enhances the light absorption ability and greatly improves the photocatalytic performance of photocatalysts. Under the synergistic effect of adsorption and photocatalysis, the degradation rate of MB reached 86.2 % in 2 h, which was significantly higher than that of the single-component photocatalyst. Finally, the synthesis of TiO2/WO3 heterojunction photocatalysts by this process and the reaction mechanism of heterojunction photocatalysts for the degradation of organic dyes were illustrated by combining experiments and DFT calculations. In conclusion, this study opens up a new process for synthesizing Z-scheme heterojunction photocatalysts, which brings new insights for photocatalytic treatment of water pollution.

La-doped Al2O3/g-C3N4 /agarose aerogel for removal of As(III) via simultaneous photocatalytic oxidation and adsorption

Attributing to its ubiquitous nature, arsenic (As) is frequently detected in various waterbodies across the globe, at concentrations often exceeding the permissible limits. In view of the acute and chronic toxicity of the arsenite species (As(III)), it is highly recommended to remove As(III) from aqueous matrices. Herein, we propose a agarose-based La-doped Al2O3/g-C3N4 (LAC) aerogel as a novel adsorptive photocatalyst for removal of As(III) via the synergistic effect of adsorption and photocatalysis. While g-C3N4 could transform As(III) to As(V) through photocatalytic oxidation, La-doped Al2O3 provided strong adsorption sites for the resulting As(V). Accordingly, the combination of adsorption and photocatalytic transformation of highly toxic As(III) into less toxic As(V), followed by subsequent adsorption of the latter can be considered as a promising technique to treat arsenic-contaminated water. The as-prepared aerogel was successfully characterized via a range of state-of-the-art microscopy, spectroscopy, and surface-specific analytical techniques. The optimized aerogel demonstrated a removal efficiency of 66.5% after 300 min of UV light irradiation. Furthermore, evaluating the effects of various reactive oxygen species via free-radical quenching experiments revealed that superoxide radicles (•O2−), singlet oxygen (1O2), and holes (h+) played a role key in the photocatalytic oxidation of As(III). More importantly, the LAC aerogel was structurally resilient and can be reused over multiple cycles, without any significant loss of the desired functionalities. Based on these deliberations, the integration of g-C3N4 with La-Al2O3 in the form of aerogel can be considered as a prospective strategy for the removal of arsenic from aqueous phase.

Preparation of poly(divinylbenzene-co-methyl acrylate) adsorbent with tunable surface hydrophilicity for atrazine removal

To efficiently remove atrazine, it is crucial to facilitate synergistic adsorption effect between aromatic structure and hydrophilic adsorption sites through tuning surface hydrophilicity. Herein, we reported a polymer adsorbent which was synthesized by copolymerizing divinylbenzene (DVB) and methyl acrylate (MA) with different monomer ratio, and subsequently hydrolyzing the copolymer to obtain carboxyl group on its surface. The surface hydrophilicity could be easily adjusted by changing the ratio of monomer and the optimal feeding ratio was 4:1 (VDVB:VMA) in terms of porosity (specific surface area 712.92 m2/g) and hydrophilicity regarding atrazine adsorption. The adsorption process followed the Langmuir isotherm with a maximum adsorption capacity of 75.75 mg/g. The mixed surface reaction and film diffusion model revealed that the adsorption procedure is dramatically controlled by film diffusion. Atrazine molecules diffusive and bound with porous adsorbent via strong hydrogen bonding between N (triazine and amine) and carboxyl groups introduced by copolymerization. Furthermore, high porosity caused by aromatic crosslinked network provided sufficient adsorption sites through π-stacking interaction. This work not only supplies a highly efficient adsorbent for atrazine removal but also enables a platform for preparation of polymers with tunable porosity and surface hydrophilicity.

Nano-Fe3O4/polymerize aniline/carbon cathode based microbial fuel cell for efficient power generation and uranium separation

Microbial fuel cells (MFCs) have gained increasing attention in the field of uranium-containing wastewater (UCW) treatment as a self-powered bioelectrochemical system (BES) due to its advantages of recovering uranium resources and generating electricity. However, the lack of catalytic active sites on the carbon fiber cathode significantly hinders the reaction performance of surface electrons with uranium ions in solution, thereby limiting the application of MFC. In this study, we propose a carbon brush (CB) cathode modification process that utilizes cyclic voltammetry synthesis technique (CVS) to polymerize aniline (PA) on the surface of carbon fibers and uniformly load nano-Fe3O4 particles (nFe3O4). The loading of PA/nFe3O4 not only significantly improve the catalytic active sites but also enhance the synergistic effect of adsorption and conductivity of CB cathode. Consequently, the nFe3O4/PA/CB-MFC showed excellent ability to continuous power generation and uranium separation. Over eight cycles of uranium separation, the nFe3O4/PA/CB-MFC exhibited an average maximum power density of 15.17 mW/m2 and a uranium separation efficiency of 95.52 %, showcasing substantial enhancements by 2.10-fold and 1.44-fold compared to the CB-MFC, respectively. Our study presents an efficient approach to enhance the efficiency of uranium separation and boost power density of MFC by increase catalytic active sites on carbon-based cathode.

Two-stage hydrothermal oxygenation for efficient removal of Cr(VI) by starch-based polyporous carbon: Wastewater application and removal mechanism

Cr(VI) is of concern because of its high mobility and toxicity. In this work, a two-stage hydrothermal strategy was used to activate the O sites of starch, and by inserting K-ion into the pores, starch-based polyporous carbon (S-PC) adsorption sites was synthesized for removal of Cr(VI). Physicochemical characterization revealed that the O content of the S-PC reached 20.66 % after activation, indicating that S-PC has excellent potential for adsorption of Cr(VI). The S-PC removal rate for 100 mg/L Cr(VI) was 96.29 %, and the adsorption capacity was 883.86 mg/g. Moreover, S-PC showed excellent resistance to interference, and an equal concentration of hetero-ions reduced the activity by less than 5 %. After 8 cycles of factory wastewater treatment, the S-PC maintained 81.15 % of its original activity, which indicated the possibility of practical application. Characterization and model analyses showed that the removal of Cr(VI) from wastewater by the S-PC was due to CC, δ-OH, ν-OH, and C-O-C groups, and the synergistic effect of adsorption and reduction was the key to the performance. This study provides a good solution for treatment of Cr(VI) plant wastewater and provides a technical reference for the use of biological macromolecules such as starch in the treatment of heavy metals.

Synergistic adsorption-photocatalysis effect of α-Fe2O3-loaded acyl chloride-covalent organic framework (AC-COF) @MIL-101 porous composites for boosted tetracycline removal

The tendency of small-sized covalent organic framework (COF) nanoparticles to easily agglomerate, and the propensity of photo-generated carriers in α-Fe2O3 to recombine pose challenges in the efficient removal of tetracycline (TC) through adsorption-photocatalysis synergy. This study addresses these challenges by introducing MIL-101, known for its excellent chemical stability and large specific surface area. The amino functional group facilitates the in-situ growth of acyl chloride-covalent organic framework (AC-COF) on the surface of MIL-101, resulting in the fabrication of AC-COF@MIL-101 with a core-shell structure. Loading α-Fe2O3 through structural regulation leads to the preparation of the final α-Fe2O3/AC-COF@MIL-101 ternary nanocomposite. In α-Fe2O3/AC-COF@MIL-101 composites, the high surface energy of AC-COF is mitigated by the strong chemical energy of NC-N, reducing AC-COF aggregation and decreasing the recombination rate of photogenerated carriers in α-Fe2O3. The heterojunction structure between AC-COF@MIL-101 and α-Fe2O3 enhances the degradation of TC, attributed to the synergistic effect of adsorption and photocatalysis. Experimental results demonstrate that α-Fe2O3/AC-COF@MIL-101 has a maximum adsorption capacity of 135.14 mg/g, achieving a 100% TC removal rate within 30 min. Compared to AC-COF, MIL-101, and α-Fe2O3, α-Fe2O3/AC-COF@MIL-101 exhibits higher adsorption capacity and photocatalytic activity. Specifically, its adsorption capacity is 2.1 times that of AC-COF, 1.8 times that of MIL-101, and 10.6 times that of α-Fe2O3. Additionally, its degradation ability is 8.6 times that of α-Fe2O3. The adsorption of TC by α-Fe2O3/AC-COF@MIL-101 occurs through monolayer chemical adsorption, and the process is exothermic. The main active species involved in the photocatalytic degradation process are h+ and ·OH. This study introduces a new ternary composite multifunctional material with high adsorption and photocatalytic performance for TC, offering a potential strategy for enhancing the synergistically adsorption-photocatalytic effect in ternary composite systems.

Efficient removal of U(VI) from aqueous solution by CNN/UiO-66 under simulated sunlight irradiation: the synergy of adsorption and photocatalysis.

The reduction of soluble U(VI) to insoluble and less toxic U(IV) by photocatalysis is an effective method to control uranium contamination. The graphitic carbon nitride nanosheet (CNN)/UiO-66 composites (CNNU) were prepared by thermal polymerization and solvothermal methods for the removal of U(VI). The morphology, crystal structure and optical properties of composites were analyzed by SEM, XRD, BET, UV-DRS, PL and EIS. The results showed the introduction of UiO-66 increased the specific surface of CNN from 9.07 m2/g to 46.24 m2/g, and effectively suppressed the recombination of photogenerated electrons and holes and improved the photocatalytic activity. The U(VI) removal capacity by adsorption and photocatalysis of CNNU was reached 779.47mg/g, which significantly higher than that of adsorption (478.38mg/g). The adsorption process was found to conform to the pseudo-second-order kinetic model and the Langmuir isothermal model. Meanwhile, U(VI) adsorbed on the CNNU was reduced to U(IV) via e- and ·O2- generated in the photocatalytic process. Therefore, this outstanding performance of CNNU in U(VI) removal is attributed to the synergistic effect of adsorption and photocatalytic reduction.

Sodium dodecyl sulfate-modified ZIF-8 for sensitive detection of tetracycline in foods under synergistic adsorption of sodium dodecyl sulfate

The abuse for tetracycline (TC) in animal husbandry causes the residue of TC in animal foods, and even in vegetables arised from the pollution of soil. The sensitive determination of TC is greatly significant for the safety monitoring of foods. Herein, sodium dodecyl sulfate (SDS) was self-assembled on zeolite imidazolate framework-8 (ZIF-8) via hydrophobic interaction. The sensitive fluorescent detection of TC was obtained based on ZIF-8@SDS as-synthesized. After adding TC to ZIF-8@SDS, the internal ZIF-8 sensitized the emission band of TC centered at 521 nm, and the external SDS adsorbed TC via hydrophobic and electrostatic interactions. On this basis, TC could be quantified by ZIF-8@SDS selectively in a concentration range from 0.01 to 60 μM within 1 min. Importantly, the synergistic adsorption effect of SDS promoted the sensitivity of ZIF-8@SDS, and the limit of detection as low as 9 nM was calculated toward TC. The concentrations of TC in fish and tomato samples were determined by ZIF-8@SDS. The relative standard deviations ranged from 1.1 % to 6.7 %, and the spiked recoveries were in the range of 85.2 %–116.2 %, proving the application potential of ZIF-8@SDS in food safety monitoring.

Enhanced and Sustainable Removal of Indoor Formaldehyde by Naturally Porous Bamboo Activated Carbon Supported with MnOx: Synergistic Effect of Adsorption and Oxidation

Novel bamboo activated carbon (BAC) catalysts decorated with manganese oxides (MnOx) were prepared with varying MnOx contents through a facile one-step redox reaction. Due to the physical anchoring effect of the natural macropore structure for catalyst active components, homogeneous MnOx nanoparticles (NPs), and high specific surface area over catalyst surface, the BAC@MnOx-N (N = 1, 2, 3, 4, 5) catalyst shows encouraging adsorption and catalytic oxidation for indoor formaldehyde (HCHO) removal at room temperature. Dynamic adsorption and catalytic activity experiments were conducted. The higher Smicro (733 m2/g) and Vmicro/Vt (82.6%) of the BAC@MnOx-4 catalyst could facilitate its excellent saturated and breakthrough adsorption capacity (5.24 ± 0.42 mg/g, 2.43 ± 0.22 mg/g). The best performer against 2 ppm HCHO is BAC@MnOx-4 catalyst, exhibiting a maximum HCHO removal efficiency of 97% for 17 h without any deactivation as RH = 0, which is higher than those of other MnOx-based catalysts. The average oxidation state and in situ DRIFTS analysis reveal that abundant oxygen vacancies on the BAC@MnOx-4 catalyst could be identified as surface-active sites of decomposing HCHO into the intermediate species (dioxymethylene and formate). This study provides a potential approach to deposit MnOx nanoparticles onto the BAC surface, and this hybrid BAC@MnOx material is promising for indoor HCHO removal at room temperature.

Simulation study of the effect of OGs on the adsorption of formaldehyde on modified activated carbon.

To explore the impact of OGs (OGs) on formaldehyde (HCHO) adsorption by modified activated carbon, this paper studied the influence of OGs on HCHO adsorption characteristics, varying the groups including ester, carboxyl, and hydroxyl. Employing density functional theory (DFT), the effects of various OGs on the structure of N-doped activated carbon through GGA-PBE exchange-correlation functionals by Materials Studio combined with Gaussian software. The types of weak interactions during the adsorption process were calculated by RDG, elucidating the mechanism through which the three OGs affect HCHO adsorption on N-doped activated carbon. The dynamic adsorption process of HCHO was simulated by molecular dynamics (MD). The influence and proportion of OGs on HCHO adsorption were subsequently analyzed using van der Waals and electrostatic interactions, determining differences in formaldehyde adsorption effects across OG types. The carboxyl group exhibits the most robust synergistic adsorption effect on the modified activated carbon. There is a notable alteration in the position and distribution of electrostatic potential extremes observed following carboxyl modification. The calculation results show that the adsorption energy of hydroxyl groups on modified activated carbon is the highest, at -5.07 kcal/mol, with a transfer charge of 0.014 e. Following the introduction of carboxyl groups, the proportion of electrostatic interactions escalated from the initial 24% to 38%. This study will provide new ideas for guiding the design of activated carbon for efficient adsorption of formaldehyde. The modified activated carbon fragments of three OGs were constructed by Materials Studio and Gaussian software, and the surface electrostatic potential polarity and area distribution, charge change, adsorption energy, and transferred charge of each molecular fragment were calculated. Moreover, cell models of OGs with the same dimensions were constructed to simulate the adsorption amount, heat of adsorption, interaction energy, radial distribution function, and hydrogen-bonding interactions for methane at room temperature and pressure. The results were consistent with the DFT simulations.

One-pot fabrication of nanoscale zero-valent iron scaffolded onto graphitic carbon nitride as bifunctional nanohybrid in sequestering U(VI) and Cr(VI) with boost performance and intrinsic mechanism

In this paper, we reported an innovative one-pot fabrication approach of a bifunctional nanohybrid through scaffolding of nanoscale zero-valent iron onto the inter-layer structure of graphitic carbon nitride in sequestering U(VI) and Cr(VI) in wastewater. The microstructures, morphologies and chemical compositions of the as–fabricated g-C3N4/NZVI nanohybrid before and after U(VI)/Cr(VI) sequestration were exploited in detail by applying various physicochemical and spectroscopic methods. Batch experimental results demonstrated that sequestration of targeted U(VI)/Cr(VI) by g-C3N4/NZVI was higher than those of pure NZVI or g-C3N4 due to the pronounced boost performance, which was ascribed from the introduction of g-C3N4 as matrix inhibited the oxidation of NZVI and improved its reactivity. The pH effect was also elucidated and it was found that lower pH facilitated the sequestration of the negatively–charged Cr(VI), while higher pH benefited the sequestration of the positively–charged U(VI). Moreover, the characterization insights into intrinsic mechanism manifested that sequestration of U(VI)/Cr(VI) was fulfilled through a synergistic effect of adsorption, reduction and coprecipitation. This work is of great significance for understanding the combined sequestration mechanism of U(VI) and Cr(VI), and usage of g-C3N4/NZVI in sequestration of severe dangerous metal ions, especially efficient detoxification of toxic cations and anions in wastewater.

Insight into the fate of 8-hydroxyquinoline and o-aminophenol in the treatment of antibiotic production wastewater by adsorption method: Synergistic or competitive adsorption

The extensive use of antibiotics leads to a surge in antibiotic production and the generation of substantial volumes of antibiotic production wastewater in China. This wastewater posed a significant threat to ecological environments due to its high pollutant concentrations, biological toxicity, and limited biodegradability. To address the presence of toxic substances, including 8-hydroxyquinoline (8-HQ) and o-aminophenol (OAP) within cephalosporin antibiotic production wastewater, the study selected hypercrosslinked resin NDA-150 with substantial surface area and porosity as adsorbent. Batch experiments demonstrated that NDA-150 exhibited favorable adsorption capabilities for both 8-HQ and OAP, and would be influenced by pH conditions. Adsorption isotherms and kinetics followed Langmuir and pseudo-second-order models, respectively. Coexisting organic compounds like methanol and glycerol weakened the adsorption process, whereas inorganic salts had minimal impact. Significantly, competitive and synergistic adsorption effects were observed in binary systems. Specifically, synergistic adsorption occurred at a mass ratio of 1:0.1 for 8-HQ and OAP, leading to an increase in the total adsorption capacity. As the concentration of OAP excessively rose, competitive adsorption was dominant, with the resin demonstrating a preference for 8-HQ, and the total adsorption capacity of NDA-150 decreased. The adsorption mechanisms were investigated through introducing competitive substances, SEM, FT-IR and XPS, and the adsorption of two substances primarily relied on hydrophobic interactions, with additional π-π interactions for 8-HQ. Desorption experiments confirmed the effectiveness of a 1:1 volumetric mixture of ethanol and 2 mol/L NaOH. This study offered a comprehensive theoretical investigation into the adsorption behavior of 8-HQ and OAP in a mixed system, and it provided practical guidance for antibiotic production wastewater treatment by adsorption method.

Synergistic effects of adsorption and chemical reduction towards the effective Cr(VI) removal in the presence of the sulfur-doped biochar material.

In this study, the anaerobic sludge withdrawn from thickener in a sewage treatment plant served as the precursor for sludge-based biochar fabrication, which was further modified via sulfur (S) heteroatom doping (i.e., S-BC). The S atom doping resulted in the adjustment of the physicochemical properties towards the carbon material, endowment of abundant functional groups on biochar surface, and increasing the binding sites between biochar and Cr(VI). Compared to the primary biochar (i.e., biochar without heteroatomic doping, named BC), S-BC exhibited a rough surface and possessed remarkable advantages in ash content, specific surface area, and pore volume. The existence of graphene carbon crystal structure for S-BC was confirmed through S-BC by XRD and FTIR analysis. The studies of adsorption kinetics and isotherms showed that pseudo-second-order kinetics and the Langmuir model more fitted the Cr(VI) removal behavior in the presence of S-BC. Therefore, the chemisorption and monolayer adsorption were the primary mechanisms involved in the Cr(VI) removal process. Additionally, XPS analysis results illustrated the aqueous Cr(VI) was efficiently eliminated through the synergistic effect of chemisorption and reduction to Cr(III) in the presence of S-BC. Moreover, S-BC could still achieve the Cr(VI) eliminating efficiency of 85.31% undergoing five cycles with unchanged functional group and crystal structure via FTIR and XRD analysis. Thus, the results of this study may shed light on a new approach for simultaneous economical sludge disposal and the sustainable remediation of the Cr(VI)-contaminated wastewater.

3D‐printed green and low‐cost porous g‐C3N4/geopolymer components for the removal of methylene blue from wastewater

AbstractIn this study, we report that geopolymer materials containing different amounts of graphitic carbon nitride (g‐C3N4) (C3N4/GP) can remove methylene blue (MB) using the synergistic effects of adsorption and photodegradation. A geopolymer containing 3 wt% g‐C3N4 (3 wt%C3N4/GP) had the best MB removal efficiency of 94.62% within 60 min, under visible light. The results showed that geopolymers can act as carriers for g‐C3N4, and the relative amount of adsorbent and photocatalyst influences the removal of MB. 3 wt%C3N4/GP was also used for additive manufacturing by using direct ink writing technology. In order to improve the efficiency of MB removal, a pore‐forming agent (K12) was added in the synthesis process to prepare three‐dimensional‐printed porous C3N4/GP. The results showed that the porous C3N4/GP was effective in removing MB. This work provides a simple strategy for preparing efficient and green materials for removing organic pollutants.

Green synthesis of β-cyclodextrin conjugated Fe3O4/NiO nanocomposites and its synergistic effect of adsorption and photocatalytic degradation for Congo red removal

The Fe3O4/NiO magnetic nanomaterials were prepared by microwave-assisted and hydrothermal synthesis in β-cyclodextrin (β-CD) solution, which can be employed as absorbents and photocatalysts for the degradation of Congo red (CR). The XRD, EDX and TEM characterizations were used to determine the structure, composition and morphology of the as-prepared samples. The interaction between Fe3O4/NiO nanoparticles and β-CD molecules was investigated by TGA and FT-IR spectra. The results indicate that β-CD molecules can encapsulate the as-prepared nanoparticles and control the nucleation and growth of Fe3O4/NiO nanocrystals to certain extent. The pyrolysis of β-CD molecules and calcination treatment produced porous structure that provides more adsorption sites for CR molecules. The effect of reaction factors including calcination temperature and pH values was studied to determine the optimum condition. In addition, the thermodynamic and kinetic parameters of CR absorbed on Fe3O4/NiO nanoparticles were measured to understand the adsorption mechanism. The high removal efficiency for CR in aqueous solution was achieved within 60 min of adsorption and 40 min of UV-light irradiation, which can be attributed to the synergistic effect of the adsorption–photodegradation process. The prepared Fe3O4/NiO nanocrystals exhibit high adsorption capacity, magnetic separability, good photocatalytic activity and renewability, making it a potential material for wastewater treatment.

Preparation of an amino-modified biochar supported sulfide nanoscale zero-valent iron composite and its efficient removal of U(vi) from wastewater by adsorption and reduction

A new amino-modified biochar supported sulfide nanoscale zero-valent iron composite (SnZVI–BC–NH2) was prepared by a simple method, which removes uranyl ions efficiently through the synergistic effect of adsorption and reduction.

Enhancing CO2/N2 and CH4/N2 separation performance by salt-modified aluminum-based metal-organic frameworks.

The energy-saving separation of CO2/N2 and CH4/N2 in the energy industry facilitates the reduction of greenhouse gas emissions and replenishes energy resources, but is a challenging separation process. The trade-off between adsorption capacity and selectivity of the adsorbents is one of the key bottlenecks in adsorption separation technologies' large-scale application in the above separation task. Herein, we introduced a series of fluoroborate or fluorosilicate salts (Cu(BF4)2, Zn(BF4)2 and ZnSiF6) into the open coordination nitrogen sites of aluminum-based metal-organic frameworks (MOF-253) to create multiple binding sites to simultaneously enhance the adsorption capacity and selectivity for the target gas. By the synergistic adsorption effect of metal ions (Cu2+ or Zn2+) and fluorinated anions (BF4- or (SiF6)2-), the single-component adsorption capacity and selectivity of salt-modified MOF-253 (MOF-253@Cu(BF4)2, MOF-253@Zn(BF4)2 and MOF-253@ZnSiF6) for CO2 and CH4 were effectively improved when compared to pristine MOF-253 at 298 K and 1 bar. In addition, the salt-modified MOF-253 has a moderate adsorption heat (<30 kJ mol-1) which could be rapidly regenerated at low energy by evacuation desorption. As confirmed by the ambient breakthrough experiments of MOF-253 and MOF-253@ZnSiF6, the real separation performance for both CO2/N2 (1/4) and CH4/N2 (1/4) was obviously improved. This work provides a feasible post-modification strategy on uncoordinated sites of the framework to improve adsorption separation performance and promote the development of ideal adsorbents with a view to realizing their application in the energy industry.