Selective Dye Adsorption Research Articles

Sustainably closed loop recycling of hierarchically porous polymer microbeads for efficient removal of cationic dyes

Herein, we designed and fabricated a hierarchically porous crosslinked polymeric microbead (PCP) with high density of functional groups for selective adsorption of cationic dyes from water.

Amino-functionalized magnetic porous organic polymer for the selective removal of toxic cationic dyes from textile wastewater

An amino-functionalized magnetic porous organic polymer (POP) was synthesized through the Friedel–Crafts reaction for selective adsorption of cationic dyes from aqueous solution.

A new multifunctional anionic 3D Zn(ii)-MOF based on heptanuclear clusters: selective adsorption of organic dyes and a dual-emitting sensor for nitroantibiotics

A new multifunctional Zn-MOF (1) based on heptanuclear clusters was synthesized, which can adsorb cationic dyes selectively and serve as a dual-emission sensor for sensitive detection of nitrofuran antibiotics via luminescence quenching process.

Acyl amide-functionalized and water-stable iron-based MOF for rapid and selective dye removal

Acyl amide-functionalized, highly porous and water-stable Fe3O cluster-based MOF for rapid and selective organic dye adsorption.

Facile Synthesis of Carbon Nanotubes and Cellulose Nanofiber Incorporated Graphene Aerogels for Selective Organic Dye Adsorption

Facile Synthesis of Carbon Nanotubes and Cellulose Nanofiber Incorporated Graphene Aerogels for Selective Organic Dye Adsorption

A Cyclic Titanium-Oxo Cluster with a Tetrathiafulvalene Connector as a Precursor for Highly Efficient Adsorbent of Cationic Dyes.

Titanium-oxo clusters (TOCs) have been studied for applications in catalysis, energy storage and transfer, light emission, and so on; however, use of TOCs for the selective adsorption of dyes has not yet been reported. Herein, a TOC compound formulated as [Ti6O3(OiPr)14(TTFTC)]4 (1, TTFTC = tetrathiafulvalene-tetracarboxylate) was successfully prepared and crystallographically characterized. Compound 1 has a cyclic structure assembled by four Ti6 clusters and four rodlike TTFTC connectors. Red compound 1 self-condenses to form a black polymeric organic-inorganic hybrid material (denoted as B-1), which was characterized by various techniques. B-1 is an amorphous TiO material that is formed by the irregular condensation of 1 by the removal of alkoxyl groups. B-1 exhibits high dye adsorption efficiency toward cationic dyes with a qe value of 651.3 mg/g at 298 K for methylene blue (MB). Moreover, B-1 can be used to selectively remove MB not only from mixed cationic-anionic dye solutions but also from some mixed cationic dyes, which is related to their structures. Kinetic, isotherm, and thermodynamic studies demonstrated that the pseudo-second-order kinetic model and Freundlich model show a good fit to the experimental data. The adsorption process involves an exothermic and entropy decreasing process. In addition, dye-adsorbed B-1 can be further used as a photocurrent-responsive material. The work opens up a new field for the application of TOCs in the selective adsorption and removal of dyes.

Copolymer networks with contorted units and highly polar groups for ultra-fast selective cationic dye adsorption and iodine uptake

Three organic copolymer networks CP1-3 were synthesized using a mild polycondensation reaction of the commercially available tetrafluoroterephthalonitrile with three different building blocks with contorted geometries and bearing two hydroxyl groups, namely, triptycene 1a, fluorescein 1b, and phenolphthalein 1c. The target cross-linked copolymers CP1-3 revealed ultra-fast uptake of the cationic dye methylene blue (MB) with an adsorption capacity reaching 300 mg/g. In addition, selectivity studies proved the preference of CP2 towards the cationic dye MB over the anionic dyes, such as, methyl orange (MO) and Congo red (CR). Copolymers CP1-3 also show superior iodine uptake properties reaching ∼150 wt% with virtually no loss in the adsorption capacity even after several successive adsorption-desorption cycles. The easy preparation and promising dyes adsorption and iodine uptake capacities promote the contorted copolymers CP1-3 as promising materials for environmental remediation applications.

Porous multicomponent chitosan/poly(ε-caprolactone)-block poly (ethylene glycol)/SiO2 aerogel@polydopamine membrane for Congo red adsorption

A composite adsorbent, chitosan//poly (ε-caprolactone)-block poly (ethylene glycol)/SiO2 aerogel@polydopamine (CS/PCL-b-PEG/SA@PDA) membrane was prepared for the adsorption of organic dyes. The matrix polymer materials of this novel adsorbent were eco-friendly. SiO2 aerogel with nanoporous network construction was fixed in the multicomponent polymer fibers through simultaneous electrospinning-electrospray technology followed by modification of polydopamine (PDA). The composite adsorbent had a maximum adsorption capacity of 598.8 mg/g for Congo red (CR) and possessed good reusability performance. This adsorbent showed excellent performance for the selective adsorption of relatively large molecule CR dyes even under high concentration of small molecule methyl orange (MO) dyes or 1 M of salt solution. The adsorption mechanism indicated that the –NH2 and –OH groups in adsorbent could generate the stronger electrostatic attraction with the –SO3- groups in CR. Meanwhile, the sufficient adsorption spaces of the adsorbent were constructed by the porous network structure of SiO2 aerogel, the accumulation of PDA particles and the porous structure of the multicomponent composite membrane. The work provided a proactive study in designing an adsorbent for the selective adsorption of organic dyes.

Synthesis of a Magnetic Co@C Material via the Design of a MOF Precursor for Efficient and Selective Adsorption of Water Pollutants

3D metal–organic frameworks (MOFs) can be appropriate templates for the fabrication of nanomaterials due to they have active sites exposed on the channel or surface, which thus provide them with improved catalytic performance. In this study, a 3D cobalt-based MOF [Co(H2bpta)]n (Co-MOF), where H4bpta denotes 2,2′,4,4′-biphenyltetracarboxylic acid, has been constructed with the use of a ligand with a high carbon content. On this basis, a 2D magnetic carbon-coated cobalt nanoparticle composite (Co@C) was prepared by using the title MOF under different temperatures. Magnetic Co@C can readily absorb dye from the solution and can thus act as an inexpensive and fast-acting adsorbent. Moreover, we have explored the adsorption isotherms, kinetics and thermodynamics of the anion dyes in detail. The adsorption capacity of the Co@C-800 for investigated methyl orange (MO) and congo red (CR) dyes were 773.48 and 495.66 mg g−1, respectively. It is noteworthy that MO adsorption is higher in existing materials. Thermodynamic studies suggest that the adsorption processes are spontaneous and exothermic. This study opens a new insight into the synthesis and application of carbon-based materials that enable the selective removal of organic dyes.Graphical AbstractA Co-MOF has been solvothermal synthesized and structurally characterized, which was used as a combined catalyst and carbon source for the synthesis of magnetic Co@C. Interestingly, the as-grown Co@C-800 exhibits high-performance selective adsorption of anionic dyes (MO and CR) with high adsorption capacities.

Superior selective adsorption of MgO with abundant oxygen vacancies to removal and recycle reactive dyes

• MgO realized the selective removal and recovery of reactive dyes. • Oxygen vacancies are the selective adsorption sites to reactive dyes. • MgO displayed high cycle stability. • The selective removal capacity was ~800 L h −1 kg −1 (MgO) . In textile engineering, wasted mixture dyes are often discharged and need to be separated and recycled. To solve this problem, MgO with abundant oxygen vacancies (F + centers, F + -MgO) is studied as a selective adsorbent for the recycling and separation of organic dyes. Herein, the adsorption performance of F + -MgO to reactive dyes Reactive blue 19, Reactive red 195, Congo red (RB19, RR195, CR), and non-reactive dyes Methylene blue and Rhodamine B (MB and RB), and the dyes mixture are estimated. Our results present that F + -MgO exhibits the properties of selective adsorption, separation, and recovery of reactive dyes from the dyes mixture. Equilibrium adsorption capacities ( q eth ) of F + -MgO are 549.45 mg/g to RB19, 348.43 mg/g to CR, and 442.48 mg/g to RR195, while hardly adsorption for MB and RhB, respectively. Moreover, RB19 can be quickly separated by F + -MgO from the mixture of RB19 and RhB in 90 s with an initial concentration of 50 mg/L. Furthermore, XPS, PL, and EPR confirm that the surface oxygen vacancies exist on the F + -MgO. And the surface oxygen vacancies are affirmed as adsorption active sites by reduced adsorption capacity after H 2 O 2 treatment and heated at high temperature in O 2 . The recycling of the used adsorbent F + -MgO is achieved by calcinated F + -MgO at high temperature, and the adsorption efficiency remains high (96.02%) after seven cycles. Notably, the adsorbed dyes (RB19) also can be reused by dissolution MgO into the solution. In this work, a low-cost, high-efficient, and recyclable adsorbent is applied to recover used-dyes from textile wastewater, presenting a new closed-loop sustainable strategy.

Robust and porous 3D-printed multifunctional hydrogels for efficient removal of cationic and anionic dyes from aqueous solution

A porous multi-layered nanocomposite hydrogel, made of poly (ethylene oxide) (PEO) and cellulose nanocrystals (CNCs), suitable for the selective adsorption of different organic dyes has been developed via 3D printing. To obtain cationic and anionic CNCs and to facilitate the adsorption of positive and negative dyes, CNCs were modified. The cross-linked nanocomposite bioink was 3D printed to form a porous multilayered hydrogel with oppositely charged layers. SEM images revealed that surface charge has a predominant effect on the porous structure of hydrogel layers. The cationic hydrogel layer exhibited a large degree of randomness in pore size and geometry, however, ionic layers displayed well-organized pore structure. The cationic and anionic layer presented pore size in the range of 10–40 μm, and 10–30 μm, respectively. Surprisingly, the observed distance between adjacent layers and delamination phenomenon suggested missing adherence between layers due to long printing time, cooling temperature, and different chemical structures in adjacent layers. 3D printed hydrogels exhibited high equilibrium swelling ratios at different levels of pH (i.e., 4, 5, 8, and 9), while fastest swelling was observed at pH 8 and pH 9.An approximate 75% of maximum adsorption ratios was observed within the first 3 h of exposure. The hydrogel exhibited almost twice the adsorption capacity for MB in comparison with MG in the pH levels studied in this work. The maximum adsorption capacity for MB and MG was observed at pH 9 for 95.23 and 82.39%, respectively. The kinetics of adsorption was analyzed via pseudo-first and second orders, and Langmuir models. The adsorption kinetics followed the pseudo-second-order model well while equilibrium adsorption from the pseudo-first order and Langmuir exhibited a large difference with experimental data. The work provides promising results for the development of CNC-PEO materials as a multilayered adsorbent for effective and efficient dye decontamination of the wastewater. • A novel CNC hydrogel with positive and negative layers was fabricated via bioprinting. • Well organized porous structure was observed in anionic hydrogel layers. • The cationic hydrogel layer exhibited a non-uniform pore size and geometry. • The hydrogel exhibited excellent adsorption capacity for cationic and anionic dye particles in an aqueous solution. • The sorption kinetic follows pseudo-second-order model.

Efficient and selective adsorption of cationic dyes with regenerated cellulose

Regenerated cellulose (RC) recovered from cellulose dissolution waste liquid was used as absorbent for dye wastewater treatment. The RC presents a uniform flake-like structure with abundant carboxyl groups, which enable its excellent adsorption selectivity for cationic dyes. The maximum adsorption capacities of 398.41 and 367.65 mg·g−1 for crystal violet and methylene blue, respectively could be achieved. The kinetic study suggested the adsorption followed the Pseudo-second-order and is a chemical adsorption. The thermodynamic behavior of RC absorbent indicated that the adsorption process was endothermic.Additionally, the RC absorbent possesses excellent recyclability. It could maintain relatively high adsorption capacity after four cycles.

Strongly co-ordinated MOF-PSF matrix for selective adsorption, separation and photodegradation of dyes

Though adsorption and separation processes using metal–organic frameworks (MOFs) for water treatment are highly promising, the disposal of adsorbed or rejected contaminants still remains a major challenge. Herein, we report photocatalytic (PC) MOF-embedded polysulfone (PSf) membranes for separation and degradation of those contaminants, thus providing a solution for decontamination of water. Fe-based MOF, namely MIL-101(Fe), have been modified to incorporate amine functional groups (NH2-MIL-101(Fe)) to enhance the optical properties (possessing a bandgap of 1.7 eV) and to control the surface charges for the selective adsorption of contaminants. Such functional Fe-MOF, is embedded into polysulfone (PSf) membrane, to give photocatalytic MOF-membrane that is successfully applied for selective adsorption, separation and degradation of adsorbed contaminants. The MOF-integrated membranes were found to inherit the properties of MOFs, that confirmed the manifestation of hydrophilic properties in membranes. The intermolecular hydrogen bonding and π-π stacking between MOF and PSf facilitated strong coordination between them. Leaching studies demonstrate the intact MOFs in PSf matrix. Two model dyes, cationic rhodamine B (RhB) and anionic methyl orange (MO), were chosen for the study to demonstrate the selectivity of membranes towards these dyes. The obtained PC MOF-membrane showed an improved water flux together with good rejection and degradation efficiency. Antifouling capacity has been tremendously increased and above-par, reaching flux recovery ratio (FRR) values above 95%. This work offers insights into designing strongly coordinated functional PC MOF membranes with polychronic effects. Good water flux and antifouling capacity (are usually the bottlenecks in existing commercial membranes) achieved in these MOF membranes make them attractive candidates for pilot applications.

Metal–ligand-based thixotropic self-healing poly (vinyl alcohol) metallohydrogels: Their application in pH-responsive drug release and selective adsorption of dyes

Metal–ligand-based thixotropic self-healing poly (vinyl alcohol) metallohydrogels: Their application in pH-responsive drug release and selective adsorption of dyes

Tunable amine-functionalized silsesquioxane-based hybrid networks for efficient removal of heavy metal ions and selective adsorption of anionic dyes

By changing the acid scavenger from NEt3 to NaHCO3, two novel kinds of amine-functionalized silsesquioxane (SQ)-based hybrid networks (PCS-N1, PCS-N2) with different molar ratios of –NH2/NH– and NH3+ were successfully prepared via nucleophilic substitution of octa(3-chloropropyl) silsesquioxane (SQ-Cl8) with triaminoethylamine, respectively. Both networks were fully characterized by FTIR, SEM, TEM, XPS, BET, TGA, WCA and solid-state 13C and 29Si NMR spectra. No porosity was observed for these two hybrid networks; however, they exhibited good thermal stability and hydrophilicity. To our surprise, they strongly adsorb heavy metal ions due to ion exchange and coordination. The adsorption capacities for Ag+ and Hg2+ are as high as 358 ± 6 and 721 ± 5 mg g−1, respectively. More interestingly, PCS-N1 can selectively adsorb the anionic dye methyl orange with a capacity as high as 731 ± 13 mg g−1. Furthermore, they regenerate easily and offer potential for water purification. This work provides a new approach to prepare and tune amine-functionalized SQ-based networks for multipurpose.

Double-Layer Nitrogen-Rich Two-Dimensional Anionic Uranyl-Organic Framework for Cation Dye Capture and Catalytic Fixation of Carbon Dioxide.

A novel two-dimensional double-layer anionic uranyl-organic framework, U-TBPCA {[NH2(CH3)2][(UO2)(TBPCA)], where H3TBPCA = 4,4',4″-s-triazine-1,3,5-triyltripamino-methylene-cyclohexane-carboxylate}, with abundant active sites and stability was obtained by assembling UO2(NO3)2·6H2O and a triazine tricarboxylate linker, TBPCA3-. Due to the flexibility of the ligand and diverse coordination modes between carboxyl groups and uranyl ions, U-TBPCA exhibits an intriguing topological structure and steric configuration. This double-layer anionic uranyl-organic framework is highly porous and can be used for selective adsorption of cationic dyes. Due to the presence of high-density metal ions and basic -NH- groups, U-TBPCA acts as an effective heterogeneous catalyst for the cycloaddition reaction of carbon dioxide with epoxy compounds. Moreover, the various modes of coordination between the tricarboxylic ligand and uranyl ion were studied by density functional theory calculations, and several simplified models were established to probe the influence of hydrogen bonding between carbon dioxide and U-TBPCA on the ability of U-TBPCA to bind carbon dioxide. This work should aid in improving our understanding of the coordination behavior of uranyl ion as well as the development and utilization of new actinide materials.

Rosin-derived porous microspheres with robust selective cationic dye adsorption

Rosin-derived porous microspheres with robust selective cationic dye adsorption

Mussel-inspired triple bionic adsorbent: Facile preparation of layered double hydroxide@polydopamine@metal-polyphenol networks and their selective adsorption of dyes in single and binary systems

To effectively address the serious human health challenges and ecological damage caused by organic dyes in wastewater, we developed a novel bionic adsorbent (LDH@PDA@MPNs) for the selective adsorption and removal of malachite green (MG) and crystalline violet (CV). The adsorbent was prepared using a facile two-step method based on mussel-inspired chemistry and metal complexation. The physicochemical structure, surface morphology, and composition of the LDH@PDA@MPNs were characterized by scanning electron microscopy, Fourier-transform infrared spectrometry, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Adsorption of MG and CV with the LDH@PDA@MPNs was evaluated. Under optimal conditions, the maximum adsorption of MG and CV by the adsorbent was 89.608 and 40.481 mg/g, respectively. The adsorption kinetics showed that the experimental data were in good agreement with the pseudo-second-order kinetic model, and the equilibrium adsorption isotherm data fitted well with the Freundlich model. The thermodynamic results indicated that the adsorption of the dyes on LDH@PDA@MPNs was a spontaneous endothermic process. Importantly, the bionic adsorbent not only shows high removal efficiency by easy regeneration with low-cost reagents but also exhibits high selectivity for dyes in both single and binary systems. Therefore, LDH@PDA@MPNs have the potential to adsorb and remove dyes from complex wastewater solutions.

Selective adsorption of cationic azo dyes onto zeolite nanorod-based membranes prepared via laser ablation

Selective adsorption of cationic azo dyes onto zeolite nanorod-based membranes prepared via laser ablation

Efficient and selective adsorption of methylene blue and methyl violet dyes by yellow passion fruit peel

ABSTRACT As an important biomass resource, agricultural waste is of great significance to improve the application value. In this study, the yellow passion fruit peel (Y-PFP) was used as a biosorbent to remove cationic dyes (methylene blue (MB) and methyl violet (MV)) by the simple treatment process. And the effects of pH, contact time, initial dye concentration, ionic strength, and temperature on the adsorption performance of Y-PFP were studied. The adsorption process was consistent with the pseudo-second-order kinetic model and Langmuir isotherm. What’s more, the maximum adsorption capacity for MB and MV was 324.7 and 485.4 mg·g−1, respectively. And Y-PFP still exhibited high removal efficiency after five desorption–adsorption cycles. Thus, Y-PFP had highly valuable for the removal of cationic dyes from wastewater with a simple preparation process, low cost, excellent adsorption capacity and selectivity.