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This research reports a rapid and scalable synthesis of MoSe2 Nanosheets (NSs), Inorganic Fullerene-Like (IF) MoSe2 and MoO3 quantum dots (QDs) with varying morphologies and crystal structures using Pulsed Laser Ablation in Liquid (PLAL) technique followed by microwave treatment of Bulk-MoSe2 powders. We show that using water as a solvent result in the formation of MoO3 QDs, single and few layered MoSe2 NSs and IF-MoSe2 structures from both Laser Modified (LM) and Laser Microwave Modified (LMM) MoSe2 samples. The presence of the predominant A1g mode in the Raman spectra of LM-MoSe2 and LMM-MoSe2 samples further showed the formation of single layer MoSe2 NS. Moreover, formation of small-sized MoSe2 heterolayers with an expanded interlayer spacing along the (002) planes for LMM samples which were subjected to microwave treatment for 30 min was demonstrated. Comparatively, for the samples subjected to microwave treatment for 60 min, most of the crystal orientations were vertical. The current study showed the controllable crystal orientation in MoSe2 samples by combined PLAL and microwave treatment. The two successive microwave steps led to change in the MoSe2 crystal orientation from horizontal to vertical. Selective oxygen incorporation induced by both PLAL and microwave treatment was also shown along the (100) and (002) planes for LM-MoSe2 and LMM-MoSe2, respectively. Understanding the selective oxygen incorporation in MoSe2 planes can shed light on the precise control of oxygenation in the crystal structures of 2D nanomaterials, synthesized heterostructures and nanocomposites.

Different morphologies and crystal phases of black titanium dioxide (TiO2) were synthesized using Pulsed Laser Ablation in Liquid (PLAL). The synthesized laser modified black TiO2 (LMB-TiO2) structures included hydrogenated anatase TiO2 nanoparticles, as the core shell structures, and TiO2 microspheres. TiO2 core-shell nanoparticles, which had crystalline-disordered structures, demonstrated the laser ablation pulse duration-dependence growth of amorphous shells and hence formation of disordered TiO2 nanoparticles with different thickness of hydrogen-doped amorphous shells were shown. TiO2 microspheres with the yolk–shell like structures (YSHL-TiO2 microspheres), on the other hand, showed the formation of rutile phases in the shell which encapsulate Lattice Expanded Planes (LEPs) in the core. The microspheres demonstrated phase transitions from anatase to rutile and size-dependent lattice interlayers expansion from 0.35 nm to 0.94 nm. The maximum particle size growth occurred when the samples were subjected to the laser ablation for 120 min. The crystal phase transition, consequently, led to the formation of heterostructured photocatalysts through construction of hydrogenated anatase TiO2 nanoparticles junctions with rutile TiO2 microspheres. The photocatalytic degradation of methylene blue (MB) using LMB-TiO2 heterostructure was tested under visible light irradiation Results showed approximately 99% of MB was degraded after 60 min. Enhanced visible light absorption and increased charge carrier lifetime due to formation of different types of heterojunctions may explain the higher photocatalytic performance of LM-TiO2 samples. Moreover, the Photoluminescence analysis indicated that hydroxyl radicals were the main active species involved in the photocatalytic degradation tests and therefore the photocatalysis mechanism was accordingly suggested.

In this paper, we report a one-step, fast and ecofriendly synthesis of layered-structured MoS2 nanosheets (NSs) by pulsed laser ablation in liquids (PLAL). The resultant MoS2 NS was used to construct TiO2–ZSM5–MoS2 nanocomposite. After impregnating ZSM5 structures with TiO2 nanoparticles (TiO2 NPs), heterojunctions of MoS2 NS were made on the fabricated TiO2–ZSM5 by microwave treatment at high temperature and pressure. Formation of 2D and 3D structures of MoS2 was shown. Crystal structure, size and shape of the synthesized nanostructures were studied by X-ray powder diffraction (XRD) and microscopy techniques. Results of the structural analysis showed that the PLAL constructed MoS2 NSs mainly had a layered morphology several micrometers in size with horizontally and vertically aligned layers. The hexagonal crystalline structure of MoS2 NS, anatase TiO2 NPs and microcrystalline ZSM5 structures were determined by XRD, high-resolution transmission electron microscopy (HRTEM) and fast Fourier transform (FFT) analysis. Formation of MoS2 NS was further shown with Raman peaks at approximately 385.30 and 407.50 cm−1 corresponding to the E1 2 g and A1g vibrational modes of MoS2 NS. The PLAL synthesized MoS2 NS demonstrated broad absorption in the visible region. Photocatalytic activity of TiO2–ZSM5–MoS2 nanocomposite was tested with arsenite. TiO2–ZSM5–MoS2 nanocomposite exhibited approximately 100% arsenite photo-conversion to arsenate.

A novel modified graphene oxide nanocomposite was fabricated via a facial procedure, aiming to removal of the aromatic pollutants from aqueous solution. The graphene oxide (GO) was functionalized with 9-aminoanthracene and produced graphene oxide-9-aminoanthracene (GO-9-AA). FTIR, XRD, TGA, TEM and Raman spectroscopy techniques were used for characterization of the adsorbents. Adsorption of naphthalene (NAP), acenaphthylene (ACN), and phenanthrene (PHN) as a model of polycyclic aromatic hydrocarbons (PAHs) was investigated by GO-9-AA. The adsorbent showed excellent removal efficiency towards PAHs from aqueous solution. Equilibrium data of the adsorption process were successfully fitted with Freundlich model from single solute system, and the maximum adsorption capacities followed the order of NAP > ACN >PHN. The kinetic analysis revealed that the overall adsorption process was fast and successfully fitted with the pseudo-second-order kinetic model. The anthracene ring makes GO-9-AA π-electron rich, thus facilitating π-π EDA interaction between NAP, ACN and PHN with GO-9-AA.

A facile and highly sensitive adsorbent for the determination of Cr(VI) ions has been developed for the first time. The sorbent was based on triazine-functionalized Fe3O4 nanoparticles and was prepared by direct silylation of magnetic nanoparticles with 3-aminopropyltriethoxysilane-2,4-bis(3,5-dimethylpyrazol)-triazine and was characterized by infrared spectroscopy, transmission electron microscopy, X-ray powder diffraction, and electron-dispersive X-ray analyses. The sorbent was applied to adsorption, preconcentration, and determination of chromate anions by the solid-phase extraction method. The effects of various factors including the pH of the solution, concentration of the adsorbate, adsorption time, and temperature on removal of Cr(VI) ions were optimized. The Cr(VI) removal efficiency of 85.8 % was achieved at the optimum initial pH of 3. The maximum adsorption capacity was 170.68 mg g−1 at an initial concentration of 75.0 mg L−1 and adsorbent dosage of 0.1 g L−1. The equilibrium data were analyzed using the Langmuir and Freundlich isotherm models by nonlinear regression analysis. The results obtained from adsorption isotherm indicated that these data can be better fitted to the Langmuir equation than the Freundlich equation. The kinetic analysis revealed that the adsorption process was successfully fitted with the pseudo-second-order kinetic model. The thermodynamic investigation demonstrated that the adsorption process is endothermic, spontaneous, and feasible in nature. Furthermore, the new sorbent was successfully applied for the determination of Cr(VI) anions in a few environmental samples using a continuous method.

In this research, Black TiO2 (BTiO2), which consisted of Rutile Based Inorganic Hollow Microspheres (RBIHM) and hydrogenated anatase TiO2 nanoparticles, decorated with MoS2 nanosheets (HBTiO2/RBIHM-MoS2 photocatalyst) was synthesized using Pulsed Laser Ablation in Liquid (PLAL) followed by microwave irradiation. Formation of vertically aligned MoS2 nanosheets, RBIHM and HBTiO2 nanoparticles were confirmed by different characterization techniques. The spectroscopic analysis revealed phase transitions in HBTiO2/RBIHM nano and microstructures along with the formation of different crystal disorders such as amorphous layers, oxygen vacancies, trivalent titanium ions and formation of molybdenum oxide (MoO3-x) in MoS2. In addition, MoS2 films in HBTiO2/RBIHM-MoS2 nanocomposite showed both Mo5+ and Mo6+ oxidation state, which was inferred that these films have a p-type conductive behavior. Furthermore, the interconnected layers of MoS2 nanosheets led to the formation of a porous like 3D nanostructure in HBTiO2/RBIHM-MoS2, which could significantly improve its photocatalytic performance. Arsenite photooxidation efficiencies of 70.3% and 96.6% and arsenate adsorption capacities of 1600 and 5200 μg g−1 were obtained for HBTiO2/RBIHM and HBTiO2/RBIHM-MoS2, respectively. The synergetic effects originated from making RBIHM-HBTiO2, RBIHM-MoS2 and MoS2–HBTiO2 heterojunctions along with the surface and morphology modification in MoS2 NSs and HBTiO2/RBIHM can explain the nanocomposite superior photocatalytic performance. The present work can trigger a broad interest in the cost-effective nanoarchitecture of visible light driven heterostructured photocatalysts.

Different morphologies and crystal phases of black titanium dioxide (TiO

Polycyclic aromatic hydrocarbons (PAHs) are a group of priority pollutants, which are classified as persistent hazardous contaminants. Herein, the adsorption of three PAHs, naphthalene (NAP), acenaphthylene (ACN), and phenanthrene (PHN), from wastewater onto NH2-SBA-15 organic–inorganic nanohybrid material as a function of pH of the media (2–10), sorbent dosage (0.5–3.5 g L−1), PAH concentration (1–18 mg g−1), and temperature (25–45 °C) were elucidated. The prepared adsorbents were characterized by scanning electron microscope, transmission electron microscopy, X-ray diffractions, and thermogravimetric analysis. Among Langmuir, Freundlich, and Temkin isotherms models, it was found that the Langmuir model gave an excellent overall fit (R2 > 0.97). The maximum adsorption capacity of 1.92, 1.41, and 0.76 mg g−1 was obtained for NAP, ACN, and PHN, respectively. Adsorption kinetics of PAHs onto NH2-SBA-15 was in accordance with the pseudo-second-order model, providing evidence that pore mass transferring was involved. PAHs' adsorption was strongly dependent on temperature, and confirmed the spontaneous and endothermic nature of the process. The optimized sorption condition was successfully applied to the real petroleum refinery wastewater samples and the adsorption capacity of NH2-SBA-15 was satisfactory for PAHs' studies as 1.67, 1.06, and 0.24 mg g−1 for NAP, ACN and PHN, respectively. Furthermore, reusability was successfully tested by five sequential recoveries.

Mesoporous silicas MCM-48 and SBA-15 were synthesized and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. Adsorption capacity of two mesoporous silica for removing naphthalene from waste water was determined. The results indicate that under similar conditions, SBA-15 had a better adsorption capacity than MCM-48. In this context, SBA-15 was modified using 3-aminopropyltrimethoxysilane and the effect of contact time, adsorbent dose, solution pH and concentration of naphthalene was investigated in batch adsorption systems. Solution pH appeared to be a key factor affecting the adsorption of naphthalene by NH2-SBA-15. The adsorption experiments revealed that a higher percentage of up to 79.3% of naphthalene was adsorbed in highly acidic media (pH of 2). The equilibrium data were analyzed using Langmuir and Freundlich isotherms and nonlinear regression analysis. This revealed that based on the correlation coefficient (R2 = 0.979) the Langmuir model provided the best fit to the results. The adsorption kinetic was determined using the pseudo-first order, pseudo-second order and Elovich kinetic models. Of the kinetics models tested, the pseudo-first-order equation provided the best fit to the results (R2 = 0.991) of the absorption of naphthalene by the adsorbent.

We report on a new sorbent for preconcentration of cadmium and lead ions that is based on triazine-functionalized magnetite nanoparticles that were prepared by direct silylation of magnetic nanoparticles with 3-aminopropyltriethoxysilane-2,4-bis(3,5-dimethylpyrazol)-triazine. The sorbent was characterized by IR spectroscopy, X-ray powder diffraction, scanning electron microscopy, thermal and elemental analysis. The sorbent was applied to the preconcentration of lead and cadmium ions which then were quantified by FAAS. The effects of sample pH value, extraction time, of type, concentration and volume of eluent, and of elution time were optimized. The limits of detection are 0.7 ng mL−1 for Pb(II) ion and 0.01 ng mL−1 for Cd(II). The effects of potentially interfering ions often found in real samples on the recovery in the determination of cadmium and lead ions in real samples were also investigated. The accuracy of the method was confirmed by analyzing the certified reference materials NIST 1571 (orchard leaves) and NIST 1572 (citrus leaves). Finally, the method was successfully applied to the determination of cadmium and lead ions in some fruit samples.