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Herein, a novel hydrogel (HG-cl-poly(AA)) was synthesized by grafting acrylic acid (AA) onto Hing gum (HG) using methylene-bis-acrylamide (MBA) as a cross-linker and ammonium persulfate (APS) as an initiator in a hot air oven. The percentage swelling of the hydrogel was examined by optimizing various reaction parameters to ensure its maximum swelling percentage. The formation of crosslinked networks was confirmed using Fourier-Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA) techniques. The surface area and hydrophilicity of the prepared hydrogel were determined using Brunauer–Emmett–Teller analyzer and wettability studies, demonstrating a clear correlation with adsorption. The adsorption of crystal violet (CV) dye on the prepared hydrogel was studied via a batch adsorption system based on the amount of adsorbent, immersion time, pH level, and initial dye concentration. The prepared hydrogel showed a 99% removal rate and an excellent adsorption capacity of 492.61mg/g due to the electrostatic, H-bonding, and dipole–dipole interactions between the adsorbent surface and dye molecules. The results were further analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The study suggests consistency with the pseudo-second-order kinetic model ($R^2=0.998$), further supported by the best data fit with the Langmuir isotherm model ($R^2=0.991$). The thermodynamic study results indicated that the adsorption process is endothermic and spontaneous. Regeneration (desorption) studies showed that the prepared hydrogel could remove CV dye from an aqueous solution and maintain the highest adsorption capacity even after multiple adsorption and desorption cycles. Therefore, the prepared HG-cl-poly(AA) hydrogel could be a potential adsorbent for dye removal and have an admirable capacity for cleaning the aquatic environment.

We present our results on nonlinear optical (NLO) of chicago sky blue 6B doped polyvinyl alcohol (PVA) film. This film was studied at 633 nm and 532 nm using a continuous wave laser. We have evaluated the sign and magnitude of the third-order nonlinearity from the closed aperture Z-scan data while the nonlinear absorption properties were assessed using the open aperture data. The chicago sky blue 6B doped PVA film exhibited nonlinear saturated absorption and strong self-defocusing effect. The limiting effect of the sample was studied and the results indicate that the film possesses good characteristic of optical limiting.

We report results from investigations of the nonlinear refractive index and nonlinear absorption coefficient of (2E)-3-[4-(Dimethylamino)phenyl]-1-(2,5-dimethylthiophen-3-yl)prop-2-en-1-one and (2E)-3-(3,4-Dimethoxyphenyl)-1-(2,5-dimethylthiophen-3-yl) prop-2-en-1-one using Z-scan technique with a continuous wave (cw) laser at wavelengths 488 nm and 514 nm. The nonlinear refractive index and nonlinear absorption coefficient of both samples were evaluated. The origin of the nonlinear effects was discussed. Optical limiting based on light induced nonlinear refractive index variation is demonstrated. The limiting thresholds were estimated for both samples. The results suggested that these materials offer promise as candidates for optical limiting and optical devices in the low power regime.

The use of adsorption capacity of porous and large-surface-area materials is an important approach to treat dye-containing effluents. In this study, the porous carbon nanocages (CNCs) were synthesized from the precursor of phenol in home-made chemical vapor deposition (CVD) setup at 600–1000^°C, and were convincingly characterized. The as-prepared CNCs are amorphous, porous and hollow, and have the size of 50–100nm in width, 100–200nm in length and several nm in thickness, causing to the large surface area of 800m²/g and pore volume of 1.63cm³/g. The growth of amorphous-like CNCs was related to the thermolysis species of phenol. Interestingly, each CNC has large volume hollow coelom and small opening (a typical ink bottle pore), being in favor of adsorption but in disfavor of desorption, thus it is very fit for acting as the adsorbent of dye. As expected, the products showed excellent adsorbility of rhodamine B when compared with the most used activated carbon having straight and slit pore structures, displaying broad application prospects in removing dye from wastewater.

The ZnO film prepared by doctor blade method are highly porous in presence of structure directing agent PEG and then can be easily sensitized by various molecules. In the present work, the nanostructured ZnO/dye hybrid film prepared by doctor blade method has been investigated in conductivity and photoconductivity measurements in view of applications in dye-sensitized solar cells (DSSC) and in optoelectronics, since electron transport in these devices plays a decisive role for the electron collection efficiency and therefore for the overall efficiency. The absorption of ZnO film sensitized by Rose Bengal dye (RB) has been studied by UV spectroscopy which indicates that after the dye is adsorbed on the ZnO electrode, its absorption spectra showed red-shift in the peak position compared to the absorbance spectra of dye in ethanol. Highly porous ZnO films are found to have high dark conductivity, probably because of a higher n-doping, which is due to higher concentration of Zn atoms in the film. On the other hand, ZnO/RB hybrid film is found to show a much higher sensitivity to illumination with visible light in photoconductivity measurements due to a higher absolute photoconductivity and lower conductivity in the dark.

In this work, we used the modified Hummers method to synthesize graphene oxide, and the redox reaction of FeCl${}_3\cdot 6$H₂O with the carboxyl group on the surface of acidified graphene was carried out to prepare magnetic nanoparticles modified on the surface of graphene (magnetic graphene nanocomposite). X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Vibrating Sample Magnetometer (VSM) and Brunauer–Emmett–Teller measurement (BET) analyses were used to characterize the nanocomposite properties. SEM and TEM images of the nanocomposite show that the magnetic nanoparticles are distributed on both sides of the graphene, and the magnetic nanoparticles diameter is between 100 and 150nm. The XRD pattern indicates that the magnetic nanoparticles are Fe₃O₄ nanoparticles. Based on the VSM, the nanocomposite exhibits a saturation magnetization value of 14.94$\mathrm{\text{emu}}\cdot {\mathrm{\text{g}}}^{-1}$. By BET measurement, the specific surface area of the nanocomposite is 26.54m${}^2\cdot {\mathrm{\text{g}}}^{-1}$, and the surface of the nanocomposite is highly porous. In the experiment of dyes adsorption, the adsorption efficiency in the solution was close to 100%. It can be applied in biomedical and environmental fields such as water purification owing to its high surface, magnetic attraction properties and good adsorption efficiency.