Flux decay is the core factor that affects membrane performance and the long-term operation for emulsion separation. Herein, a double-barrier and multi-functional membrane for emulsion separation was ...fabricated via in-situ growth of MIL-88A on the Fe-phenolic network. This membrane performs enhanced anti-pollution ability of hydration layer and the self-cleaning ability of photo-Fenton catalysis to ensure high separation performance. Wettability and organic matter degradation performance of the membranes were experimentally determined. It could well implement emulsion separation (flux ∼ 2602.55 LMH; separation efficiency ∼ 99 %) solely by gravity-driven. After a brief photo-Fenton catalysis, the water flux recovery ratios (FRR) of the membrane after 8 cycles (320 min) reach 94.87 % (CTAB-stabilized emulsion) and 89.27 % (SDS-stabilized emulsion), respectively. Interestingly, the flux and FRR of the membrane exhibit a negative relationship when it circularly filters different types of emulsion. Based on the Hermia models analysis, this difference mainly originates from that electrostatic repulsion assists in mitigating irreversible pollution while disfavors rapid demulsification and improving flux. The reverse was true when there was the opposite potential between the membrane surface and emulsions. Meanwhile, a novel optical transmission system is applied to transmit light in cloudy emulsion to achieve long-term operation (90 min).
Display omitted
•M4 was prepared by in-situ growth of MIL-88A on the Fe-phenolic network.•M4 performed an enhanced wettability and self-cleaning ability of photo-Fenton.•M4 could prevent contamination from the process and terminal simultaneously.•The membrane fouling behaviors were analyzed in detail by Hermia models.•A novel optical transmission system could support long-term operation of M4.
Gadolinium is known to be a most widely used but toxic rare-earth element, and Gd(III) ions exist in aqueous media will bring about serious damage to the ecosystem. However, few work on the ...application of adsorption strategy with enough high Gd(III) uptake is reported. Since the hollow mesoporous silica nanospheres (HMSNs) and amino-phosphonic acid (APA) compounds have shown inherent advantage for being used as effective adsorbent and chelating ligand in toxic metals adsorption due to their remarkable properties. Herein, we follow the cleaner production philosophy, proposing for the first time to modify the HMSNs nanomaterial with APA group by reacting phosphorous acid with cyano-functionalized hollow mesoporous SiO2 (CFHMSNs) via one-step reaction under solvent-free conditions, and apply to remove Gd(III) form wastewater. The obtained materials are characterized by a variety of techniques. Characterization results show that the APA-functionalized material (AFHMSNs) has ordered mesoporous structure, high stability and large surface area (825.3 m2/g). The maximum uptake of Gd(III) for AFHMSNs (387.3 mg/g) is much higher than those of the reported adsorbents because of the high surface area, and multifunctional chelating interactions of the adsorbent with Gd(III) ions. Gd(III) adsorption onto AFHMSNs can be well described by the Langmuir isotherm and pseudo second order kinetics model. The adsorption is chemical complexation mechanism which is proposed based on FTIR and XPS analysis. It is found for the first time that the adsorption of Gd(III) onto AFHMSNs slightly enhanced with the coexistence of Al3+ in the relatively lower concentrations, which may be due to the synergistic effect of pseudo-boehmite. This work provides a favorable strategy to design and synthesis of hollow mesoporous nanomaterial with superior adsorption performances and potential for the cleanup of toxic metals from wastewater.
Display omitted
•The adsorbent was prepared via one-step reaction under solvent-free strategy.•High adsorption capacity and rapid adsorption rate of Gd(III) were observed.•The existence of lower concentrations Al3+ can promote the Gd(III) adsorption.•The adsorption mechanism may be explained by the chelation interaction.
Developing an emulsion separation material with one-step in-situ purifying capability and improved security in applications, especially for subsequent scale-up, is valuable but remains a challenge. ...Herein, the amphiphilic sponge (PA@RGO@MS) was prepared via impregnation and in-situ growth of the negatively charged hydrophilic phytic acid (PA) and the hydrophobic reduced graphene oxide (RGO) on the surface of the melamine sponge (MS) and applied in emulsion purification. The mechanics, wettability, absorption performance of the PA@RGO@MS were analyzed to identify its potential for stable demulsification. Results show that the PA@RGO@MS could purify emulsions (turbidity removal rate = 99.7%; TOC removal rate = 94.14%) in-situ in one step by simple shock absorption, profited from the hydrophilic and demulsification capability of PA, oil absorption of RGO, and wide reaction and storage space of MS. Targeting the emulsion with distinct properties (density, viscosity, and concentration) of the oil phase, the PA@RGO@MS could efficiently enable the purification. Meanwhile, the powerful flame-retardant granted from PA ensures the safe shipment and storage of sponges. The favorable cyclability (turbidity removal rate > 98.5% and TOC removal rate > 89.5% after 10 cycles) and diversified operating modes enhance the practical value of the PA@RGO@MS.
Display omitted
•The PA@RGO@MS was successfully fabricated by impregnation and in-situ growth.•The PA and RGO@MS undertake the task of demulsification and oil absorption, respectively.•The PA@RGO@MS could efficiently realize one-step in-situ emulsion purification.•The PA@RGO@MS could achieve emulsion separation in multiple ways.•The PA@RGO@MS owns enhanced security during storage or transportation.
Display omitted
•A Janus aerogel was tailored by one-step hydrothermal-freeze casting method without further modification.•An evaporation rate of 3.65 kg m-2h−1 with a solar-to-vapor efficiency of ...98.9 % is obtained.•The Janus aerogel demonstrates good salt tolerance and long-term stability.•The Janus aerogel has good performance on the purification of high salt wastewater.
The interfacial solar evaporation, as a promising energy-efficient desalination technology, still urgently requires the development of efficiency and salt-resistance of the three-dimensional evaporators. Herein, Janus aerogels with macroporous air capsule structure were prepared by one-step hydrothermal self-assembly and freeze-drying treatment of dimethyldiallylammonium chloride acrylamide polymer-graphene colloidal solution, and then used for photothermal evaporation of high salt wastewater. The Janus P(AM-DMDAAC)/GO aerogels (PGA) exhibited asymmetric wettability and roughness at their upper and bottom surfaces, which are favorable for photothermal conversion at the hydrophobic interface and sufficient water supply at the hydrophilic interface. The evaporation rate of 3.65 kg m−2h−1 and the photothermal conversion efficiency of 98.9 % were obtained under 1.0 sun irradiation, which was attributed to the special three-dimensional structure of the Janus PGA. Benefited from the excellent water supply properties and the special air capsule framework, the as-obtained Janus PGA evaporator exhibited robust recyclability and durability in simulated seawater for 10 d without any salt crystallization. This study provides a simple strategy toward construct Janus aerogels with macroporous air capsule structure for solar evaporation and high-salinity wastewater treatment.
Display omitted
•A sustainable and elastic biomass evaporator is fabricated for highly efficient solar steam generation.•EC-PPy-MO decorated with nanotube PPy has a stronger photothermal effect than ...EC-PPy decorated with spherical particles.•The EC-PPy-MO evaporator with melamine foam support layer can deliver an evaporation rate of ∼ 2.8 kg m-2h−1 under one sun.•Excellent salt resistance performance and stable evaporation performance in high-salt wastewater.
Three-dimensional (3D) materials that capture sunlight for desalination provide one promising solution to acquiring freshwater resources, but salt deposition and mechanical stability provide additional hurdles for continuous operation. Herein, this study presents a sustainable and elastic biomass evaporator (EC-PPy-MO) with the hierarchical micro-nano water transport channel and air cavities formed by hydrophilic tubular polypyrrole seamlessly integrated onto the external surface of biomass foam. The EC-PPy-MO foam exhibits high light absorption ability (∼91%) over a broad wavelength due to the waveguide effect of the polypyrrole with a slender tubular morphology and the hierarchical micro-nano structure in the biomass matrix. The EC-PPy-MO foam helps stabilize a thin water film to provide an efficient evaporative interface surface and ensure effective thermal insulation. As a result, the EC-PPy-MO foam evaporator parallel to the horizontal plane demonstrates a rapid evaporation rate of about 1.8 kg m-2h−1 under 1 sun irradiation. In parallel, the evaporator can maintain efficient evaporation without salt fouling in a solution with 7% NaCl salinity, while largely salt fouling appears when higher than 15% brine. However, EC-PPy-MO with melamine foam support floating in 25 wt% brine can be evaporated for 72 h without significant salt fouling accumulation, up to ∼ 2.8 kg m-2h−1. This is attributed to the fact that the exposed sides of the 3D EC-PPy-MO foam can eliminate the boundary Marangoni phenomenon resulting in the appearance of no significant salt fouling, while the exposed cold evaporation surface enhances the evaporation rate of the EC-PPy-MO foam. More importantly, EC-PPy-MO foam exhibits excellent mechanical stability, chemical stability, and elasticity, as well as remarkable water purification ability.
Hydrophobic and oleophilic biomass-based block materials are considered to be highly promising candidates used for oil/water separation. However, the crucial hydrophobic modification process often ...involves various toxic and hazardous organic substances or requires high energy inputs. Inspired by the flame retardant principle of phosphorus-containing flame retardants, herein, an Enteromorpha-derived carbon (ADP-EP) aerogel with a water contact angle of 144.2° was prepared by successive freeze-shaping, freeze-drying and low-temperature carbonization treatment (300 °C), using NH4H2PO4 (ADP) as a modifier. The results demonstrated that the introduction of NH4H2PO4 could largely facilitate the removal of oxygenated groups from the pristine EP aerogels and enhance their surface roughness, thereby achieving surface hydrophobic modification. Featuring intrinsic low density, rich porosity and strong lipophilicity, the as-fabricated ADP-EP aerogels exhibited exceptional performance in both oil spill adsorption (~140 g/g) and water-in-oil emulsion separation. Moreover, the good reusability for oil uptake was also realized thanks to its robust mechanical compressibility and thermal stability. This work provides a facile, economical and eco-friendly route to obtain a desirable hydrophobic/oleophilic surface.
Display omitted
•A superhydrophobic NH4H2PO4-modified Enteromorpha (ADP-EP) aerogel was prepared after low-temperature carbonization treatment.•The formation of hydrophobic carbonaceous structure was highly promoted after involving NH4H2PO4.•The ADP-EP aerogels exhibited excellent oil spill uptake and water-in-oil emulsion separation property.•The mechanism of NH4H2PO4 to enhance the surface hydrophobicity of EP aerogel was clarified.
Efficient treatment of complex rare earth (RE) smelting wastewater has drawn great attention due to its potential environmental toxicity and the high demand of RE in modern technologies. However, it ...is still a challenge to achieve the simultaneous recovering RE and separating oil from wastewater. This study makes the first attempt to fabricate a versatile membrane, namely H-UiO-66-PF2, by loading 2-hydroxyphosphono acetic acid functionalized UiO-66 on polyester fabric through one-pot reaction strategy, and reports for the first time the simultaneous separation of oil/water mixtures and recovery of Gd(III). The H-UiO-66-PF2 exhibits standout oil/water separation performance with water flux up to 126,300 L·m−2·h−1 and separation efficiency above 99.8 %. Besides, the maximum adsorption capacity of H-UiO-66-PF2 for Gd(III) is reached 156.5 mg/g, adsorption equilibrium time is within 60 min. Moreover, the H-UiO-66-PF2 possesses high stability and recyclability, even after 20 cycles, separation efficiency and flux are 98.9 % and 105,200 L·m−2·h−1, respectively. Most notably, in addition to the separation of oil/water emulsion, complete Gd(III) capture is achieved from wastewater through filtration process. Therefore, this work provides a new design strategy to fabricate the composite membrane with great prospects for sophisticated smelting wastewater cleanup.
Display omitted
•A multifunctional membrane based on UiO-66 and polyester fabric is developed.•The membrane has a water flux of >126,300 L·m−2·h−1 with >99.8 % oil rejection.•The adsorption capacity of the membrane for Gd(III) is as high as 156.5 mg/g.•The membrane can simultaneously capture Gd(III) and separate oil-in-water emulsion.
Oil fractions containing highly toxic and hazardous organic contaminants can not only cause severe environmental disasters, but also an undesired waste of resources. Given the exceptional performance ...of persulfates in the removal of persistent and refractory organic pollutants from aqueous media, herein, a peroxymonosulfate-based Pickering emulsion catalytic (PPEC) system was constructed for the hazardous oil purification, using super-amphiphilic graphene as a solid emulsifier and a heterogeneous catalyst simultaneously. Combined detailed instrumental analysis with theoretical calculations, we find that the incorporation of pyridinic N and its oxide significantly facilitated the formation of super-amphiphilic graphene and successfully induced the formation of Pickering emulsion. In addition to stabilizing the PPEC system, super-amphiphilic graphene can also achieve efficient removal of Sudan III (simulated lipophilic organic pollutant) by activating peroxymonosulfate (PMS) to generate •O2– and 1O2. Results showed that 80 mg/L Sudan III (20 mL) could be fully degraded within 30 min using 10 mL 5 mmol PMS. More significantly, our proposed PPEC system also exhibited excellent property in the purification of practical waste engine oil. This study provides new insights into the purification and recovery of waste oil.
Display omitted
•PMS-based Pickering emulsion catalysis system was constructed for hazardous oil purification.•Pyridinic N and pyridine N-oxide highly facilitated the formation of super-amphiphilic graphene.•Super-amphiphilic graphene participated simultaneously as emulsifier and catalyst.•The PPEC system also exhibited outstanding performance in the purification of actual waste engine oil.
The development of highly efficient adsorptive material for the selective capture of Pd(II), and re-utilization of spent Pd(II)-loaded adsorbent as an efficient catalyst for organic synthesis are of ...great significance, but challenging. Particularly, the heterogeneous palladium-catalyzed Suzuki reaction in aqueous media is much more challenging than that of homogeneous. Herein, several novel Pd(II) ion-imprinted polymers (PIIPs) based on dendritic fibrous silica particles are constructed by surface ion imprinting technology (SIIT), using Schiff base and pyridine groups functionalized organosilicon as functional monomer. The PIIP-3 prepared by 3 g of functional monomer exhibits the best adsorption performance, and shows ultrafast (10 min) and selective capture of Pd(II) with high uptake capacity (382.5 mg/g). Moreover, the waste Pd(II) loaded PIIP-3 (PIIP-3-Pd) can serve as a catalyst towards the Suzuki reaction in water, affording 94.2 % yield of the desired product. Interestingly, the PIIP-3-Pd can be reused 12 times without an appreciable decrease in catalytic activity, which is probably due to the imprinted cavity and specific recognition site of PIIP-3 can match and recapture Pd active species in a complex catalytic environment. Thus, this work demonstrates huge potentials of SIIT to enhance the selectivity of adsorption process and increase the lifetime of catalysts.
Display omitted
•A new ion-imprinted polymer was developed using DFSPs as the carrier.•The PIIP-3 exhibited ultrafast, excellent and selective adsorption for Pd(II).•The waste PIIP-3-Pd could be used as a reusable and heterogeneous catalyst.
