Dual Adsorption Research Articles

Competitive interactions of NH3 and toluene with biochar modified by pre- and post-treatments of H3PO4 in dual adsorption systems

Biochar modified by H3PO4 treatment can be used to purify malodorous gases during bio-drying of sludge, but the current understanding of multi-component adsorption of malodorous gases through biochar is limited. This study examined the adsorption mechanism of mixed malodorous gases including toluene and ammonia (NH3) on two kinds of biochar modified via H3PO4 pretreatment before and after pyrolysis. The biochar obtained by H3PO4 pretreatment of biomass before pyrolysis (C550) preferred to adsorb NH3 whether in the single or the dual system. In contrast, the biochar obtained by H3PO4 reprocessing after pyrolysis of biomass (C350-550) tended to adsorb toluene in the dual system but was more efficient in absorbing NH3 in the single system. The pseudo-second-order kinetic model indicated the synergistic adsorption between NH3 and toluene for all biochar samples. In-situ DRIFTS of C350-550 during adsorption demonstrated the formation of amino functional groups caused by NH3 chemical adsorption with -OH (or -COOH) in the dual system. These increases in basic groups on C350-550 could enhance the surface zero potential point of C350-550, thereby improving the non-polarity of C350-550 and benefit the adsorption of weak polar toluene.

Enhancing adsorption performance and selectivity for uranium by constructing biaxial adsorption sites on eco-friendly bamboo strips

Amidoxime-based materials are currently the most promising adsorbents for sustainable extraction uranium from seawater. However, in practical applications, the strong affinity of amidoxime-based materials for vanadium seriously interferes with the extraction uranium from seawater. Herein, a novel environmentally friendly and degradable adsorbent is firstly designed through grafting animal protein on natural bamboo strips (BS). In detail, the casein hydrolysates (sodium caseinate, acid hydrolyzed casein and casein phosphopeptide) are grafted with amidoximated bamboo strips (SCAOBS, AHCAOBS and CPPAOBS) by chemical cross-linking and amide reactions to construct biaxial adsorption sites, including amidoxime and amino acid branched chains. The optimal adsorption pH of SCAOBS, AHCAOBS and CPPAOBS were 5, 7 and 7, the adsorption capacities were 186.3, 204.0 and 68.6 mg g−1, and the attenuation was 23.1%, 17.7% and 20.2% after 5 cycles, respectively. Utilizing the weavability of BS, SCAOBS, AHCAOBS and CPPAOBS adsorbents are woven and floated in the Yellow Sea Basin, exhibiting that the adsorption capacity of uranium is 0.84, 1.21 and 0.81 mg g−1, respectively, much higher than that of vanadium. Evenly, the adsorption capacity of AHCAOBS for uranium is about 15.3 times that of vanadium (0.077 mg g−1). Through DFT spatial structure optimization, there are indeed biaxial dual adsorption sites (–COOH from amino acid and C = N-OH from amidoxime groups) between amino acids and amidoxime branched chains, and even the spatial structure of biaxial triple adsorption sites (–COOH from amino acid, O = C-N from amide bond and C = N-OH from amidoxime groups) is more stable, thereby breaking this bottleneck from the vanadium interference for the amidoxime-based adsorption materials.

Amphoteric retarder for long-standing cementing: Preparation, properties and working mechanism

Amphoteric retarder (AIDA) was prepared by radical copolymerization of 2-acrylamido-2-methyl propane sulfonic acid (AMPS), itaconic acid (IA), 2-(Methacryloyloxy) ethyltrimethylammonium chloride (DMC) and methyl allyl polyethenoxy ether (TPEG). The characteristics of AIDA were verified by FTIR and 1HNMR. In addition, the performances of AIDA in cement slurry including thickening time, compressive strength developments, and adaptability to long standing cementing with lager temperature differences were investigated. The results indicated that AIDA possessed excellent temperature-resistance (180 °C) and good adaptability to long standing cementing with larger temperature differences of 90 °C. Finally, the retarding mechanism of AIDA was revealed through transverse relaxation time (T2) distribution, XRD tests, and adsorption behavior of AIDA on cement particles. The results demonstrated that the stronger retarding effect of AIDA originated from the dual adsorption of AIDA on cement particles compared with AMPS-IA copolymer (PAI). AIDA outperformed PAI in its adaptability to long-term cementing, which was responsible to (a): the adsorbed amount of AIDA at higher temperature is higher than that of lower temperatures, therefore, AIDA has a stronger retarding effect at higher temperature and weaker retarding effect at lower temperature. (b) Compared to PAI, the adsorption strength of AIDA is weaker and easy to de-adsorb, so both the retarding effect and the hydration reaction of cement are realized. Thus, the super-retarding phenomenon of cement slurry containing AIDA is effectively prevented.

Ni-Al layered double hydroxide-coupled layered mesoporous titanium dioxide (Ni-Al LDH/LM-TiO2) composites with integrated adsorption-photocatalysis performance.

Nickel aluminum layered double hydroxides (Ni-Al LDHs) and layered mesoporous titanium dioxide (LM-TiO2) were prepared via a simple precipitation process and novel precipitation-peptization method, respectively, and Ni-Al LDH-coupled LM-TiO2 (Ni-Al LDH/LM-TiO2) composites with dual adsorption and photodegradation properties were obtained via the hydrothermal approach. The adsorption and photocatalytic properties were investigated in detail with methyl orange as the target, and the coupling mechanism was systematically studied. The sample with the best performance was recovered after photocatalytic degradation, which was labeled as 11% Ni-Al LDH/LM TiO2(ST), and characterization and stability studies were carried out. The results showed that Ni-Al LDHs showed good adsorption for pollutants. Ni-Al LDH coupling enhanced the absorption of UV and visible light, and the transmission and separation of photogenerated carriers were also significantly promoted, which was conducive to improving the photocatalytic activity. After treatment in the dark for 30 min, the adsorption of methyl orange by 11% Ni-Al LDHs/LM-TiO2 reached 55.18%. Under illumination for 30 min, the decolorization rate of methyl orange solution reached 87.54%, and the composites also showed an excellent recycling performance and stability.

Simultaneous adsorption and fluorescent detection of Cr(VI) via lanthanide coordinating polymeric porous microparticles

Functional porous microparticles that enable simultaneous adsorption removal and online monitoring of hazardous hexavalent chromium are of great importance for effective remediation of Cr(VI) pollution. Herein, we have synthesized, for the first time, an oligomer bearing aromatic backbone and pendent carboxyl, sulfonate as well as amidoxime groups, which has been further employed as the dual functional ligand to coordinate with lanthanide ions of Tb3+ via a facile one-step solvent exchange induced self-assembling, leading to generation of the cube-like fluorescent porous microparticles. Thanks to their porous structure, abundant surface binding sites as well as green fluorescence emission that can be selectively quenched by Cr(VI), the obtained lanthanide coordinated polymeric porous microparticles exhibited both competitive adsorption and fluorescent detection of Cr(VI). More specifically, the optimized fluorescent porous microparticles demonstrated a maximum Cr(VI) adsorption capacity of 553.92 mg·g−1 and a limit of detection for Cr(VI) down to 1.92 nM according to systematic adsorption and detection experiments. On account of scalable synthesis of oligomer ligand, facile preparation of microparticles as well as their competitive dual adsorption and detection of Cr(VI), the current work basically opens new way for design and fabrication of advanced materials for heavy metal ions pollution controls.

Fabrication of waste paper/graphene oxide three-dimensional aerogel with dual adsorption capacity toward methylene blue and ciprofloxacin

Fabrication of waste paper/graphene oxide three-dimensional aerogel with dual adsorption capacity toward methylene blue and ciprofloxacin

Correction to: Efficient dual adsorption of eosin Y and methylene blue from aqueous solution using nanocomposite of graphene oxide nanosheets and ZnO nanospheres

For the correction, the acknowledgement section has been added per the authors’ request.

Simultaneous scavenging of As(V) and safranin O dye by Mg/Al LDH-zeolite heterocoagulated materials: The effect of adsorbent synthesis approach on its efficiency in static and dynamic system

Increasing demand for simultaneous removal of organic and inorganic pollutants from wastewaters causes a growing popularity of hybrid materials with dual adsorption properties. This study investigated the effect of heterocoagulated materials synthesis conditions on their adsorption efficiency both in static and dynamic conditions. The heterostructures containing layered double hydroxides (LDHs) and zeolite were synthesized via two approaches: facile, one-pot hydrothermal synthesis and co-precipitation of LDH on the hydrothermally obtained zeolite. The low-cost and abundant kaolin group minerals have been used as precursors for the zeolite synthesis. The results emphasized the advantage of hydrothermal materials in removal of As(V) and cationic dye safranin O (SO) in both single and dual-component systems. The high specific surface area of hydrothermal materials (139.5 m2/g) influenced the superior SO removal properties. All of the obtained heterostructures were also highly effective in As(V) adsorption due to their significant anion exchange capacity of 56.5–120.4 meq/100 g. The best material was transformed into hydrogel beads by encapsulation with the use of sodium alginate polymer. It was tested in a custom-made flow-through column. In addition to the efficient adsorbates removal, the dynamic experiments highlighted the importance of the physical behavior of the adsorbent granules in the adsorption column.

Efficient dual adsorption of eosin Y and methylene blue from aqueous solution using nanocomposite of graphene oxide nanosheets and ZnO nanospheres

Efficient dual adsorption of eosin Y and methylene blue from aqueous solution using nanocomposite of graphene oxide nanosheets and ZnO nanospheres

Preparation of efficient adsorbent with dual adsorption function based on semi-coke: Adsorption properties and mechanisms

Solid waste oil shale semi-coke (SC) is considered as a potential material for the preparation of adsorbents due to its rich organic and inorganic components. However, the dense structure and the complex form of the components present make it unsatisfactory for adsorption. In this study, using Alkali corrosion under hydrothermal condition, SC was prepared as an adsorbent material PSSC with excellent adsorption performance for both anionic and cationic dyes. The related characterization analysis showed that most of the organic matter and silicates of SC reacted with inorganic matter to form silicon carbide. The specific surface area of PSSC increased significantly (from 7.47 m2/g to 1353.99 m2/g) leading to the maximum adsorption of PSSC on Methylene blue (MB) and Congo red (CR) reached at 974.66 mg/g and 562.41 mg/g, respectively, which far exceeded the adsorption of SC on both dyes. Finally, the adsorption mechanisms were revealed from the structural and energetic perspectives. The results showed that the modification process increased the type and number of adsorption sites, and that these adsorption sites exhibited different capturing abilities for the two dyes with the change of contact temperature.

Phosphorus and potassium recovery from anaerobically digested olive mill wastewater using modified zeolite, fly ash and zeolitic fly ash: a comparative study

AbstractBACKGROUNDNutrient recovery from wastewater is gaining attention in the frame of circular economy. In this study, Ca(OH)2‐treated zeolite (CaT‐Z), lignite fly ash (FA) and zeolitic fly ash (ZFA) were primarily used to adsorb phosphate phosphorus (PO4‐P) from anaerobically digested olive mill wastewater (ADOMW). The simultaneous recovery of potassium (K) was also examined based on adsorption and desorption data. The fractionation of adsorbed P was determined as an important parameter for its plant availability.RESULTSMore P was adsorbed from ADOMW on ZFA and FA (up to 4.35 and 5.21 mg g−1, respectively) than on CaT‐Z (2.62 mg g−1). An increased P adsorption on ZFA and FA was observed between incubation times of 7 and 14 days. The sequential desorption procedure verified the trend of P adsorption capacities and showed that the plant‐available P (NaHCO3‐P) amounted to 1.34, 2.34 and 1.69 mg g−1 CaT‐Z, ZFA and FA, respectively. After 14 days, CaT‐Z and ZFA adsorbed much more K (19.2 and 20.5 mg g−1, respectively) than FA (4.3 mg g−1). The desorption of exchangeable K confirmed this difference. Scanning electron microscopy–energy dispersive spectrometry analyses indicated P adsorption and surface precipitation as Ca–P phases as well as K+ for Ca2+ ion exchange on the loaded adsorbents.CONCLUSIONSZFA was more efficient for dual adsorption combining the properties of the zeolitic fraction (enhanced K adsorption) and pristine FA (P adsorption on Ca‐bearing phases). The sufficient concentrations of plant‐available P and K on the three adsorbents suggest their potential use as soil amendments. © 2022 Society of Chemical Industry (SCI).

Bioinspired Construction of Magnetic Nano Stirring Rods with Radially Aligned Dual Mesopores and Intrinsic Rapid Adsorption of Palladium

Bioinspired Construction of Magnetic Nano Stirring Rods with Radially Aligned Dual Mesopores and Intrinsic Rapid Adsorption of Palladium

Bioinspired Construction of Magnetic Nano Stirring Rods with Radially Aligned Dual Mesopores and Intrinsic Rapid Adsorption of Palladium

Bioinspired Construction of Magnetic Nano Stirring Rods with Radially Aligned Dual Mesopores and Intrinsic Rapid Adsorption of Palladium

Bioinspired Construction of Magnetic Nano Stirring Rods with Radially Aligned Dual Mesopores and Intrinsic Rapid Adsorption of Palladium

Bioinspired Construction of Magnetic Nano Stirring Rods with Radially Aligned Dual Mesopores and Intrinsic Rapid Adsorption of Palladium

An electrochemically induced dual-site adsorption composite film of Ni-MOF derivative/NiCo LDH for selective bromide-ion extraction

An electrochemically induced electrode with bromide ion (Br-) dual adsorption sites was obtained by in-situ growing of Ni-MOF derivative/NiCo layered double hydroxide (Ni-MOF(D)/NiCo LDH) composite film on the stainless-steel wire mesh via an electrodeposition-assisted solvothermal method, which exhibited excellent Br- selectivity from ionic mixture solutions of Br-, NO3– and I- in an electrochemically switched ion exchange (ESIX) system. The Br- extraction capacity was as high as 126.30 mg·g−1 and the separation factors of Br-/NO3– and Br-/I- were 8.29 and 4.83 respectively. Combining the simulation and experimental results, it was confirmed that the highly efficient selective extraction of Br- in neutral solution should be derived from the dual-site (i.e., electrochemically induced laminate metal coordination sites and interlayer anion exchange sites of NiCo LDH) adsorption. Furthermore, the electrode demonstrated superior adsorption–desorption performance and electrochemical stability because of the in-situ growth strategy, which enhanced the binding force between NiCo LDH and substrate and improved the electrical conductivity of NiCo LDH, and provided a storage space for Br-. This study served deep understanding of ions selective extraction mechanism of LDH-based materials in the ESIX process, which could be a novel reaction concept for the design of those electrodes with specific recognition sites in the applications of them in other fields such as supercapacitors, sensors and batteries.

Rational construction of a CNTs@VO2 nanosheets modified separator for enhancing the performance of lithium-sulfur batteries.

Although lithium-sulfur (Li-S) batteries possess great potential to become the next generation of energy storage technology due to their fivefold higher energy density than commercial lithium-ion batteries, their practical application is still hindered by their poor cycling stability, especially resulting from the disturbing shuttle effect of soluble intermediates. In this study, vanadium dioxide (VO2) nanosheets were successfully grown onto CNTs to form CNTs@VO2 through hydrothermal and calcining processes. The hollow structure of the high conductive CNTs offers internal space and mesopores to accommodate the electrolyte combined with the polar metal oxide VO2 nanosheets providing the chemical anchoring. The hollow binary core-shell host acting as the nanoreactor that serves as the modifier of the separator results in the intensive physical and chemical dual adsorption of lithium polysulfide species (LiPSs), promoting the conversion of long-chain LiPSs to alleviate the shuttle effect significantly and boosting the performance. In addition, the CNTs enhance the electronic conductivity and the electrolyte infiltration of the separator. Notably, the modified separator demonstrates a high initial discharge capacity of 1397 mA h g-1 at 0.2C and retains a stable cycling ability with a reversible capacity of 965 mA h g-1 over 200 cycles at 1C. Even for the high sulfur loading of 7.4 mg cm-2, it can deliver a high areal capacity of 5.4 mA h cm-2 at 0.5C.

Methane adsorption on shales and application of temperature-related composite models based on dual adsorption modes

There are some controversies in shale gas about adsorption mechanisms and thermodynamics. This paper studied the adsorption of methane on two shale samples at pressures up to 20 MPa and temperatures in the range of 40–80 °C. Two composite models based on monolayer adsorption and filling of micropores were proposed and used for the fitting of the experimental isotherms under multiple temperatures. The fitting results show that the composite models lead to better fitting effects for isotherms and under low pressure compared to the Langmuir models thus being appropriate models for fitting. Using the composite models, the competition of two adsorption modes was investigated that the filling of micropores hardly appear until pressure rises to approximately 2 MPa. The isosteric heat and entropy change were determined by the Clapeyron equation and weighted average method, showing their dependence on the competition of two adsorption modes at different adsorbed amounts. These findings not only determine two novel models for describing shale gas adsorption but also reveal the adsorption process and associated thermodynamics.

2-aminopyridine functionalized magnetic core–shell Fe3O4@polypyrrole composite for removal of Mn (VII) from aqueous solution by double-layer adsorption

• Fe 3 O 4 @PPy-AP composite is synthesized for rapid Mn (VII) adsorption from solution. • The maximum adsorption capacity of the composite is 781.25 mg g-1 at 318.15 K. • Both the N atoms in PPy and AP can adsorb Mn (VII) through coordination effect. 2-aminopyridine functionalized magnetic core–shell Fe 3 O 4 @polypyrrole structure (Fe 3 O 4 @PPy-AP composite) is fabricated to remove Mn (VII) from water. The adsorbent fully combines the easy magnetic separation of Fe 3 O 4 microspheres, the excellent corrosion resistance of PPy, as well as double-layer adsorption for Mn (VII) of PPy and AP. The effects of time, temperature and pH on the adsorption performances and adsorption mechanism are investigated in detail, for which the significance of structure of Fe 3 O 4 @PPy-AP composite is elucidated. It is clear that the adsorption process is chemical adsorption. The adsorption kinetics and isotherm is more suitable for pseudo-second order model and Freundlich model. The initial adsorption rate is 67.43 min g mg −1 , and the maximum adsorption capacity can reach 781.25 mg g −1 at 318.15 K. The film diffusion dominates the speed of the entire adsorption process. Adsorption thermodynamic calculations show that ΔS and ΔH are 198.33 J mol −1 K −1 and 37.88 kJ mol −1 , respectively, and the decreased ΔG with increasing temperature indicates that the adsorption process is endothermic and spontaneous. The Fe 3 O 4 @PPy-AP composite only loses less than 1% of Mn (VII) adsorption capacity after each adsorption–desorption cycle. This Fe 3 O 4 @PPy-AP composite with good magnetic properties and dual adsorption properties has broad application prospects in the rapid separation and adsorption of heavy metal ions.

Reusable Nanocomposite Membranes for Highly Efficient Arsenite and Arsenate Dual Removal from Water

AbstractNanocomposite membranes (NCMs) of poly(vinylidene fluoride‐hexafluoropropylene), PVDF‐HFP, with different yttrium carbonate and magnetite loadings, are prepared, and their dual adsorption capacity over neutral arsenite and anionic arsenate species is evaluated. The nanoparticles (NPs) and the corresponding NCMs are fully characterized in morphology, microstructure, thermal, and surface properties. The nanocomposite membranes present a micrometric porous structure with a homogeneous distribution of the active nanoparticles. Chemical, thermal, and water‐contact angle characteristics of the NCMs point out that they maintain the chemical and thermal stability of the polymer while improving the wettability. Arsenic removal depends on NP loading and pH of the media. For instance, efficiencies close to 100% are achieved for arsenate species under acidic conditions, while adsorption capacity over arsenite is also incremented above 80%. Fe3O4/PVDF‐HFP nanocomposite shows a dual affinity for the adsorption of As(III) and As(V) species, with the maximum adsorption capacities of 92.82 and 137.08 mg g−1, respectively. In addition, both NCMs are easily activated and reused without significant efficiency loss. Consequently, the nanocomposite membranes represent low‐cost, reusable, and efficient water remediation systems suitable for the long‐term removal of As(III) and As(V) under conditions mimicking real polluted surface and groundwater.

Two volumetric techniques for determining the transport properties of hydrogen gas in polymer

We report two different volumetric analysis techniques to determine the transport properties of hydrogen dissolved in rubbery polymers. This measures the volume filled by the released hydrogen from rubber by gas collection in a graduated cylinder and by gas chromatography after exposure a sample with high-pressure hydrogen and decompression. From the measurement results, the uptake (C∞), diffusion coefficient (D), and solubility (S) of hydrogen are quantified by employing an upgraded diffusion analysis program. These methods are applied to three cylindrical rubber samples. Dual adsorption behaviors with increasing pressure are observed for all rubber samples. C∞ follows Henry's law up to ∼15 MPa, whereas the Langmuir model applies up to 90 MPa. No size dependence are observed for C∞ and S, whereas pressure-dependent D shows Knudsen and bulk diffusion behavior below and above a critical pressure, respectively. The S and D measured in two techniques are consistent with each other within the expanded uncertainty evaluated. A COMSOL simulation is compared with experimental investigations.