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Currently, textile and food industries produce a significant volume of sewages containing azo dyes and other organic pollutants. These effluents are serious environmental threats, so new methods for their treatment and the degradation of azo dyes are attracting much attention. Composite materials based on TiO2 modified by noble metals and nanoceria show high activity in the photodegradation of organic contaminates and are proposed for hydrogen synthesis as well. To optimize the treatment of contaminants, different processes can combine including the strategies of adsorption, photoluminescence, photocatalysis, etc. The synthesized TiO2-based nanomaterials (sols, powders) will be exploited for bioremediation due to their small size and surface plasmon resonance from noble metals. Binary nanocomposites based on TiO2 were obtained by the chemical co-precipitation method from solutions of titanium tetraisopropoxide (TTIP) and inorganic salts of cerium, silver, and palladium. It has been stated that TiO2 is represented by anatase with primary particle size (CSR) from 8.5 to 16.8 nm, depending on the nature and concentration of the dopant. It is shown that Ag is reduced on the surface of anatase particles and blocks their growth, while Pd and Ce penetrate the titanium dioxide matrix in the form of small clusters with the deformation of the anatase crystal lattice. Nanocomposite particles formed loose and fragile aggregates, which spontaneously dispersed in solutions of dyes with the formation of colloid-stable sols, required the use of a centrifugal field for their sedimentation. Nanoparticles of TiO2&Pd were electronegative and others were electropositive according to the values 4.1÷9.6 of ZPC (zero point of charge). It was shown that the particles of all composites sorbed Methylene Blue (MB) without photocatalytic activity under the visible light to any dye. Moreover, anionic dyes such as OrangeG (Or-G) and Methyl Orange (MO) were excellently discolorated in the presence of TiO2&Pd system; cationic dyes of MB and Rhodamine B (RhB) discolorated too with the TiO2, TiO2&CeO2, and TiO2&Ag systems under UV light action. As such, photocatalysis tests showed that Orange-G’s and MO’s discoloration was higher for TiO2&Pd (2 wt. %) and TiO2 systems with the correlation coefficient R² 0.999. [ABSTRACT FROM AUTHOR]

One-pot co-precipitation of target molecules e.g. organic dyes and the synthesis of a crystal containing microporous–mesoporous regimes of zeolitic imidazolate frameworks-8 (ZIF-8) are reported. The synthesis method can be used for cationic (rhodamine B (RhB), methylene blue (MB)), and anionic (methyl blue (MeB)) dyes. The crystal growth of the ZIF-8 crystals takes place via an intermediate phase of zinc hydroxyl nitrate (Zn5(OH)8(NO3)2) nanosheets that enabled the adsorption of the target molecules i.e., RhB, MB, and MeB into their layers. The dye molecules play a role during crystal formation. The successful encapsulation of the dye molecules was proved via diffuse reflectance spectroscopy (DRS) and electrochemical measurements e.g., cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The materials were investigated for carbon dioxide (CO2) adsorption and adenosine triphosphate (ATP) biosensing. ZIF-8, RhB@ZIF-8, MB@ZIF-8, and MeB@ZIF-8 offered CO2 adsorption capacities of 0.80, 0.84, 0.85, and 0.53 mmol g−1, respectively. The encapsulated cationic molecules improved the adsorption performance compared to anionic molecules inside the crystal. The materials were also tested as a fluorescent probe for ATP biosensing. The simple synthesis procedure offered new materials with tunable surface properties and the potential for multi-functional applications. [ABSTRACT FROM AUTHOR]

A multifunctional anionic Zn-MOF, formulated as {[NH2(CH3)2][Zn7(μ3-OH)3(L)6(H2O)]·24H2O·6DMA}n (1) (where H2L = 6-methoxy-2,2′-sulfone-4,4′-dicarboxylic acid and DMA = dimethylacetamide) has been solvothermally synthesized, which is based on rare heptanuclear [Zn7(μ3-OH)3(COO)12] clusters possessing large 3D intersecting channels. Through a cation-exchange process, 1 can selectively adsorb cationic organic dyes, and the adsorption capacities for methylene blue (MB), rhodamine B (RhB) and crystal violet (CV) are 219.9, 114.6 and 197.6 mg g−1, respectively. Moreover, the obtained RhB@1 composite features dual-emissive characteristics and can serve as a dual-channel sensor for selective sensing of traces of NF antibiotics (NFT and NFZ), with detection limits of 0.89 μM and 0.95 μM, respectively. The mechanism study shows that the quenching process is mainly ascribed to the synthetic effect of IFE and FRET. [ABSTRACT FROM AUTHOR]

Multinuclear cluster-based metal–organic frameworks (MOFs) have shown excellent activity in toxic chemical removal from wastewater due to their high porosity, functionality and water stability. In this regard, a highly porous, water-stable Fe-MOF was fabricated and the efficiency of its acyl amide-functionalized pores for organic dye removal was investigated. Different anionic and cationic dyes including methyl orange (MO), methyl red (MR), congo red (CR), rose-bengal B (Ros B), rhodamine B (Rhod B) and methylene blue (MB) were applied to determine the Fe-MOF efficiency. The presence of acyl amide improves the host-guest interaction of the framework towards anionic dyes, specifically MO with an adsorption capacity of 232.5 mg g−1. Interestingly, the Fe-MOF shows one of the fastest adsorptions of MO with a kinetic constant of 0.013 g mg−1 min−1 which is faster than those of some of the well-known MOFs such as UiO-66, MOF-235, MIL-53, MIL-101, UiO-66-NO2 and ZIF-67. The adsorption mechanism, uptake kinetics and selectivity of the framework for different dyes were also studied. Overall, water stable Fe-MOF with a high permanent porosity as well as rational decoration of pores with specific functions, improved the size and charge selective dye removal by the preferred H-bonding and π–π interactions. [ABSTRACT FROM AUTHOR]

Cubic fluorite CeO2 has band gap energy similar to that of TiO2, exhibiting a certain photocatalytic activity, and it can be widely used to adsorb and degrade various organic dyes. Herein, self-assembled MXene-CeO2 composites with CeO2 nanoparticles uniformly loaded on the surface and between the layers of MXene was prepared by the hydrothermal method. Through the microstructure analysis of MXene-CeO2 composites, it was proved that the MXene could not only effectively prevented the accumulation of CeO2 nanoparticles during the production process but also provided a large attachment site for the generation of nanoparticles. In addition, the self-assembled MXene-CeO2 exhibited good adsorption efficiency for adsorption of the cationic dyes rhodamine B (RhB) and methylene blue (MB) under ultraviolet light irradiation. Therefore, the prepared MXene-CeO2 composite nanomaterial has significantly higher performance in degrading dyes and can be widely used in wastewater treatment. [ABSTRACT FROM AUTHOR]

A new water-tolerant nickel-based coordination polymer (Ni-PDC) was prepared by facile precipitation method employing 1,3-propanedicarboxylic acid (PDC) and nickel acetate. The prepared coordination polymer was utilized in the adsorptive removal of anionic (Congo red and methyl orange) and cationic dyes (methylene blue and rhodamine B) from aqueous solutions. The obtained data demonstrated that Ni-PDC is an efficient adsorbent for removing anionic dyes from aqueous solution with high efficiency and fast kinetic. The prepared Ni-PDC was found to be very effective for removing anionic dyes as Congo red eliminated from the aqueous solution more than 96% during the first 2 mins. Moreover, the pH has not remarkable effect on the removal efficiency of Congo red by Ni-PDC and thus neutral pH is the best medium for its adsorption. The Ni-PDC can be recovered after desorbing organic dyes, and the removal efficiency was found to be nearly unchanged after four cycles. [ABSTRACT FROM AUTHOR]

Rhodamine B (RhB) is a cationic organic dye widely used industrially, mainly in the textile and food industries. Then, the work aims to study on the photocatalytic degradation of RhB dye, under UV and visible radiation, using photocatalyst silica-based materials synthesized by sol-gel route with different solvents (ethanol and n-propanol) and catalysts (C12H27N, HNO3, NH4OH, and NaOH) to the hydrolysis and condensation of tetraorthosilicate (TEOS). In addition, the effect of doping with silver nanoparticles (AgNPs) was evaluated on the photocatalytic activity. The samples were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), N2 porosimetry, zeta potential measurements (ZP), and Fourier transform infrared spectroscopy (FTIR). To evaluate the photocatalytic activity, photocatalytic tests were carried out in a stirred batch reactor, with the photocatalyst in suspension, under ultraviolet and visible radiation, and the target molecule chosen was the Rhodamine B dye (RhB). The photocatalyst Si–HNO3–AgNPs showed the best photocatalytic activity with a degradation of the RhB dye of 90.16% (k = 0.0198 min−1, under ultraviolet radiation) and 82.79% (k = 0.0148 min−1, under visible radiation), after 120 min of reaction; while under the same conditions, the commercial catalyst TiO2 (P25) showed a degradation of 50.02% and 42.14%, respectively. [ABSTRACT FROM AUTHOR]

• A series of Zr-MOCs with different functional groups were synthesized. • Zr-MOCs exhibit efficient adsorption for MO and RhB. • ZrT-1 exhibits the most excellent adsorption ability for MO and RhB. • The mechanism of dye adsorption was investigated in detail. The adsorption of organic dyes from wastewater is an efficient approach to reduce dye pollution for water resources and land. Herein, a series of zirconium-based metal-organic cages (Zr-MOCs) with different functional groups, ZrT-1, ZrT-1-Br, ZrT-1-NH 2 and ZrT-1-OH, were synthesized by solvothermal that can be applied to remove methyl orange (MO) and rhodamine B (RhB). The adsorption kinetics of Zr-MOCs was fitted well by pseudo-second-order. ZrT-1 exhibits the most excellent adsorption ability for MO and RhB compared with the other Zr-MOCs due to the highest pore volume. Interestingly, Zr-MOCs can remove both anionic dye (MO) and cationic dye (RhB) due to the synergistic interplay between pore volume, electrostatic interaction, π-π interaction and hydrogen bonding. The adsorption behaviors of MO and RhB on ZrT-1 are suitable to the Langmuir model that belong to the monolayer adsorption. The maximum adsorption capacities for MO and RhB towards ZrT-1 are 190 mg/g and 227 mg/g at 25 °C, pH=7 and the initial dye concentration of 80 mg/L, respectively. A series of zirconium-based metal-organic cages with different functional groups were synthesized and exhibit efficient adsorption for MO and RhB. [Display omitted] [ABSTRACT FROM AUTHOR]

LaNiO 3 @SiO 2 /PW 12 nanomaterial was synthesized and used as a new hybrid adsorbent for fast and selective removal of cationic organic dye pollutants such as methylene blue (MB) and rhodamine B (RhB) from aqueous solutions. Perovskite-type LaNiO 3 nanoparticles were synthesized by an auto-combustion method and coated with a SiO 2 shell. Then, silica-coated LaNiO 3 nanoparticles were used as an active support of Keggin-type phosphotungstic acid (H 3 PW 12 O 40, abbreviate as PW 12) for the synthesis of novel LaNiO 3 @SiO 2 /PW 12 hybrid nanomaterial. The LaNiO 3 @SiO 2 /PW 12 nanomaterial was characterized by using FT-IR, XRD, SEM, EDX and AFM analyses and tested as a new absorbent for the removal of cationic methylene blue (MB) and rhodamine B and anionic methyl orange (MO) organic dyes from aqueous solutions. The results of the adsorption measurements demonstrated that the LaNiO 3 @SiO 2 /PW 12 hybrid exhibited superior performance to pristine LaNiO 3 , suggesting that PW 12 polyoxometalate play a critical role in the adsorption performance improvement. The effect of some important parameters such as dye concentration, pH, and temperature was studied on the dye removal process. Furthermore, the selective adsorption of the LaNiO 3 @SiO 2 /PW 12 nanohybrid was investigated towards MB/RhB, MB/MO, MO/RhB and MB/MO/RhB mixed dye solutions. The hybrid showed rapid and selective adsorption for cationic MB and RhB dyes from mixed dye solutions. Also, it can separate easily from the aqueous solutions and recycled three times without any loss of adsorption ability. Based on the results of this study, the hybrid is an efficient adsorbent for eliminating cationic dyes. [ABSTRACT FROM AUTHOR]

Abstract In this work, the immobilization of silver nanoparticles on lignosulfonate functionalized kaolin composite (LS-kaolin-Ag) was fabricated by a facile reduction method without additional reductant and stabilizer. Transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy (FTIR) were used to confirm the successful preparation of LS-kaolin-Ag composite. The catalytic reduction tests on both cationic dye rhodamine B and anionic dye Congo red indicated the high catalytic activities of this as-prepared LS-kaolin-Ag composite. Meanwhile, this catalyst showed good recyclability for dye decolorization with just a little decrease of conversion percent in five successive reactions. These results suggest that LS-kaolin-Ag composite as an efficient and cost-effective catalyst shows great application potential for the decolorization of various organic dyes. Highlights • Lignosulfonate kaolin-Ag composite was prepared by a facile reduction method. • LS-kaolin-Ag catalyst exhibited high catalytic activity for dye decolorization. • LS-kaolin-Ag catalyst showed good catalytic stability and recyclability. [ABSTRACT FROM AUTHOR]

The Ta 2 O 5 –CdS composites with the various ratios of Ta 2 O 5 /CdS were synthesized to study their employment in the photodecomposition of RhB (rhodamine B)/MB (methylene blue). The samples characterized by XRD, FESEM, EDS, and TEM proved the formation of the Ta 2 O 5 –CdS with cauliflower morphology. According to DRS analysis, Ta 2 O 5 –CdS exhibited redshifts, and their band-gaps (2.00 eV and 2.10 eV for Ta 2 O 5 /CdS = 1 and 3) decreased in contrast to pure CdS (2.18 eV). The BET-specific surface areas (9.221 m2/g) of the Ta 2 O 5 –CdS composite (Ta 2 O 5 /CdS = 1) measured by N 2 adsorption-desorption isotherms were enhanced in contrast to pure CdS (1.817 m2/g). Moreover, MB photodecomposition by Ta 2 O 5 –CdS with the weight ratios of Ta 2 O 5 /CdS = 3 and 1 improved to 90% and 99%, respectively, in contrast to pure CdS (80%). Besides, the Ta 2 O 5 –CdS composite (Ta 2 O 5 /CdS = 1) exhibited the highest RhB decomposition (97%). Hence, for the first time, this study has surveyed the photodecomposition of the cationic dyes by the Ta 2 O 5 –CdS with excellent photocatalytic performance. The role of active species was detected through species quenching tests. A reliable mechanism was suggested to reveal how the RhB/MB decomposition was promoted compared to CdS. The photodecomposition results corresponded to the pseudo first order kinetic model. [Display omitted] • The Ta 2 O 5 –CdS composite was synthesized by a novel chemical impregnation method. • The cationic dye photodecomposition by Ta 2 O 5 –CdS was studied for the first time. • The effect of various parameters on the photodecomposition rate was investigated. • The decomposition of MB, RhB, and phenol by Ta 2 O 5 –CdS was enhanced compared to CdS. • The likely mechanism of photodecomposition by the Ta 2 O 5 –CdS composite was studied. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyimide-based COFs are synthesized through the condensation reaction. • Alkaline hydrolysis treatment is performed to modify the COF surface. • Negatively charged carboxylate anions are generated after hydrolysis treatment. • Hydrolyzed COFs act as good adsorbent for cationic MB dye with superior selectivity. The efficient removal of organic dyes from wastewater is still a major challenge, especially for the massive production of dyeing technology. Herein, polyimide-based covalent-organic frameworks (COFs) with a highly ordered conjugated architecture are synthesized through the condensation reaction of pyromellitic dianhydride (PMDA) with tris (4-aminophenyl) amine (TAPA). Due to a repeated cyclic structure, COFs subjected to alkaline hydrolysis can offer a high density of negatively charged carboxylate anions as adsorption sites for cationic methylene blue (MB) dye through electrostatic interactions. The maximum adsorption capacity of MB on hydrolyzed COFs is measured to be 315.6 mg/g at pH = 10 and room temperature. Significantly, hydrolyzed COFs exhibit superior adsorption selectivity for MB in a mixture solution with methyl orange (MO) and rhodamine B (RhB). Overall, hydrolyzed COFs are good candidates to serve as an efficient adsorbent for the removal of MB with a high selectivity in the posttreatment of the dyeing process. The employment of COFs with a highly active surface in this study provides new insights for the future development of efficient adsorbents for organic dyes. [ABSTRACT FROM AUTHOR]

Water pollution by organic dyes poses great challenge to the environment and living organism. Hence effective removal of organic dyes by cost effective methods have received significant attention in recent years. Herein, we report the complete removal of organic dyes (rhodamine B), methylene blue) and eosin yellow) from water via effective adsorption by MoO 3 catalyst. Hydrothermally synthesised MoO 2 (1) and amorphous MoS x (2) using ammonium molybdate without and with thiourea exhibited low dye adsorption. In contrast, crystalline micro/nanoplates of MoO 3 (3 and 4) obtained from calcination of 1 and 2 showed highly enhanced dye adsorption. Particularly 4 showed higher dye adsorption compared to 3. UV–Visible absorption studies confirmed complete removal of organic dyes upon stirring with MoO 3 catalyst. Dye removal studies further revealed that cationic dyes are adsorbed faster than anionic dye that could be attributed to the surface charge of MoO 3. Interestingly, the adsorbed dyes were not released from MoO 3 for more than 50 days. The exhausted MoO 3 catalyst can be recovered by annealing at 400 °C. MoO 3 catalyst has also been used as packing materials in dropper column and demonstrated effective removal of dyes by passing through dyes separately as well as mixture. MoO 3 nanoplates/rods prepared by hydrothermal-calcination method exhibited superior dye adsorption while stirring as well as filtration. [Display omitted] • Fabricating nano/micro plates of MoO 3 via hydrothermal-calcination method. • Highly enhanced dye adsorption by MoO 3 nano/micro plates fabricated from MoS x. • Easy removal of mixed dyes by filtration using dropper column. • Regenerating used MoO 3 adsorbent by calcination. [ABSTRACT FROM AUTHOR]

Recently, organic dyes are highly found in wastewater because of the plastic, painting, cosmetics, paper, leather, and food industries. They are dangerous and can affect the environment in addition to the human beings. Many methods were studied in order to get rid of them. Among all the techniques, adsorption was determined to be a successful, economic, ecofriendly, and efficient one. Zinc oxide nanoparticles were complexed with curcumin in order to generate zinc curcumin oxide nanoparticles that will be used as adsorbent. The efficiency of zinc curcumin oxide nanoparticles as adsorbent was investigated for different organic dyes such as congo red (CR), methyl orange (MO), methylene blue (MB), rhodamine 6G (Rh6G), and rhodamine B (RhB). The effect of pH was investigated in this study for the diverse anionic and cationic dyes. The highest adsorption capacities q e of the dyes were determined for CR, MO, MB, Rh6G, and RhB to be 94.54, 44.38, 34.71, 38.184, and 28.34 mg/g respectively. Only congo red had the highest adsorption capacity at an acidic pH while the other dyes had the highest adsorption capacity at a basic pH. In addition, all the adsorption processes that were studied followed a pseudo-second order kinetic model. [Display omitted] • Zinc curcumin oxide nanoparticles were synthesized and used as adsorbent. • Congo red had the highest adsorption capacity in acidic medium. • Methylene blue, rhodamine 6G and rhodamine B had highest adsorption capacity in basic solutions. • Even though methyl orange is anionic, it was adsorbed better in basic medium. • All the adsorption processes studied followed a pseudo-second order kinetic model. [ABSTRACT FROM AUTHOR]

In this article, the potential of alginate stabilized silver nanoparticles beads for efficient sorption of methylene blue, malachite green, and rhodamine B from aqueous solutions was investigated. The adsorption data have been correlated with both Freundlich and Langmuir adsorption models. The kinetic studies for dyes adsorption showed rapid sorption dynamics by second-order kinetic model. The common problem of classical adsorbents towards efficient recyclability was overcome when alginate stabilized silver nanoparticles beads was used. The alginate stabilized silver nanoparticles beads were successfully recycled for 25 successive adsorption-desorption cycles indicating its high reusability. [ABSTRACT FROM PUBLISHER]

Two novel POM-based inorganic-organic hybrid compounds {[(Cu·L1′·(4, 4′-bpy) 2 ·2H 2 O)]·(β-Mo 8 O 26)} n (1) and {[Cu·L2′·(4, 4′-bpy)]·[Cu·L2′·(β-Mo 8 O 26)]·4H 2 O} n (2) (4, 4′-bpy = 4, 4′-bipyridine) have been synthesized under different hydrothermal conditions. There exist obliqued interpenetrating 2D network in compound 2 with the oblique angle of 43°. The adsorption properties of the compounds on cationic dyes were relatively good. • POM-based coordination polymers were synthesized with in-situ hydrolysis of cyano-ligands. • There exist obliqued interpenetrating 2D network in compound 2 with the oblique angle of 43°. • The adsorption properties of the compounds on cationic dyes were relatively good. Through adjusting the different ligands and incorporating 4, 4′-bipyridine, two novel POM-based inorganic–organic hybrid compounds {[(Cu·L1′·(4, 4′-bpy) 2 ·2H 2 O)]·(β-Mo 8 O 26)} n (1) and {[Cu·L2′·(4, 4′-bpy)]·[Cu·L2′·(β-Mo 8 O 26)]·4H 2 O} n (2) [4, 4′-bpy = 4, 4′-bipyridine, L1′=1, 4-bis(pyridinio-4-carboxylato)-butane, L2′=1, 6-bis(pyridinio-4-carboxylato)-hexane] have been synthesized under different hydrothermal conditions. The two compounds were assembled by 4, 4′-bpy, CuCl 2 , carboxyl ligands from in-situ hydrolysis of cyano group and POM clusters, which are rarely observed in POM-based inorganic–organic hybrid compounds. Compounds 1 – 2 were characterized by single crystal X-ray diffraction, infrared spectrum (IR), and powder X-ray diffraction (PXRD). Compounds 1 – 2 have been studied for removal of organic dyes such as methylene blue (MB), methyl orange (MO) and rhodamine B (RhB). [ABSTRACT FROM AUTHOR]

• A new dithiocarbamate– polyoxometalate nanohybrid was prepared. • Nanohybrid 1 was formed from uniform and nanoplate-like nanoparticles with thickness of 30–50 nm. • Nanohybrid 1 was used as an efficient sonocatalyst for degradation of cationic Rhodamine B dye. • The sonocatalytic activity of nanohybrid 1 was more than of H 3 PMo 12 O 40. • Nanohybrid 1 could be readily recycled and reused. A new organic-inorganic nanohybrid compound, ([Cu{(HOCH 2 CH 2) 2 NCS 2 } 2 ] 3 [PMo 12 O 40 ] (1)), has been prepared by sonochemical technique using copper(II) dithiocarbamate complex and a Keggin-type polyoxomolybdate in this research. FT-IR, XRD, FE-SEM, TEM, EDX, UV–Vis, TGA, BET, and single crystal XRD analyses were applied to describe the properties of the composition of the nanohybrid. Compound (1) is composed of [PMo 12 O 40 ]3– building blocks and [Cu{(HOCH 2 CH 2) 2 NCS 2 } 2 ]1+ cationic moieties, and electrostatic forces and substantial hydrogen-bonding interactions were applied to pack them; and consequently, a three dimensional supramolecular framework was made based on single-crystal X-ray diffraction patterns. FE-SEM and TEM images approved the morphology of the nanohybrid sample to be extremely penetrable. Very good sonocatalytic performance is shown by this supramolecular nanohybrid in the degradation of Rhodamine B (RhB), which is a cationic organic dye. The results showed complete degradation of cationic RhB (25 mg/L) within 70 min with the rate constant of 0.039min−1 in the presence of nanohybrid (1) and H 2 O 2 (4 mmol/L). Also, sonocatalytic activity of the nanohybrid (1) was higher than H 3 PMo 12 O 40 , showing that the combining Cu(DEDTC) 2 complex with H 3 PMo 12 O 40 could be an excellent choice to improve its sonocatalytic activity. The used nanohybrid (1) can be recycled after easily removing from the reaction media by centrifuging, and there was no considerable loss of catalytic activity and retention of the structure. [ABSTRACT FROM AUTHOR]

In this work, a magnetic P 2 W 18 O 62 @ Fe 3 O 4 /MIL-101 (Fe) nanocomposite as a stable and effective ternary adsorbent was fabricated by the hydrothermal method and utilized for the elimination of organic dyes from aqueous solutions. Characterization of magnetic nanocomposite was accomplished by FT-IR, XRD, SEM, EDX, BET specific surface area, and VSM measurements. The findings demonstrated the prosperous encapsulation of P 2 W 18 O 62 heteropolyanions within the porous MIL-101(Fe) framework. The encapsulated sample with a less pore volume and surface area compared with the MOF, displayed a considerable diminish in both pore volume and surface area due to the incorporation of huge Dowson-type POM within the cages of MOF. The fabricated nanocomposite was used as an efficient adsorbent for the elimination of cationic dyes (such as rhodamine B and methylene blue) from aqueous solutions. Influencing factors including primary dye concentration, pH, temperature, and adsorbent dose on the adsorption potency of the P 2 W 18 O 62 @ Fe 3 O 4 /MIL-101 (Fe) were checked. Adsorption isotherms were investigated by Freundlich and Langmuir models and obtained results confirmed that dyes adsorption pursued the Langmuir model. Moreover, the fabricated nanocomposite had high stability and recoverability without any alter in structure. According to these results, P 2 W 18 O 62 @ Fe 3 O 4 /MIL-101 (Fe) can act as a reusable effective adsorbent for the fast elimination of diverse cationic dyes from aqueous solutions. K 6 P 2 W 18 O 62 polyoxometalate was encapsulated into magnetic Fe 3 O 4 /MIL-101 (Fe) metal-organic framework and applied as a new magnetically recoverable ternary adsorbent to remove organic dyes from aqueous solutions. Image 1 [ABSTRACT FROM AUTHOR]

The photocatalytic activity of sepiolite was examined for degradation of several dye compounds under visible light irradiation. Higher adsorption capacities and greater photocatalytic performance of cationic dyes (rhodamine B and methylene blue) were observed on sepiolite, in comparison with anionic dyes (orange II and trypan blue). Superiority in the photocatalytic activity of cationic dyes is attributed to the strong electrostatic attraction and photosensitization properties of cationic dye molecules. Sepiolite has degraded 45.3% rhodamine B within 120 min, which is the greatest photocatalytic degradation efficiency when compared with other dyes. Subsequently, the reusability of spent sepiolite after adsorption of rhodamine B was evaluated by the degradation of trypan blue under the visible light irradiation. The photocatalytic degradation performance of trypan blue by spent sepiolite after adsorption of rhodamine B increased about twice as much as with pristine sepiolite, indicating that the dye-sensitized photocatalytic process could enhance the photocatalytic degradation ability of sepiolite. Through radical scavenger tests, it was found that a superoxide radical is mainly responsible for rhodamine B degradation. The possible mechanism of rhodamine B degradation under visible light irradiation was proposed. The sepiolite could be a potential catalyst for the degradation of organic pollutants in wastewater under solar light. [ABSTRACT FROM AUTHOR]