Cellulosic aerogel from water hyacinth (WH) was synthesized to address the dual environmental issues of water hyacinth pollution and the production of a green material. Raw WH was treated with sodium hydroxide (NaOH) with microwave assistance and in combination with hydrogen peroxide (H 2 O 2 ). The results from X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) showed that lignin and hemicellulose were markedly decreased after treatment, reducing from 24.02% hemicellulose and 5.67% lignin in raw WH to 8.32 and 1.92%, respectively. Cellulose aerogel from the pretreated WH had a high porosity of 98.8% with a density of 0.0162 g•cm −3 and a low thermal conductivity of 0.030 W•m −1 •K −1 . After modification with methyl trimethoxysilane (MTMS) to produce a highly hydrophobic material, WH aerogel exhibited high stability for oil absorption at a capacity of 43.3, 43.15, 40.40, and 41.88 (g•g −1 ) with diesel oil (DO), motor oil (MO), and their mixture with water (DO + W and MO + W), respectively. The adsorption remained stable after 10 cycles.

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An effective and green technique was performed for the synthesis of copper nanoparticles (CuNPs) from an organic resource using the Cocoa pod (CCP) extract as a reducing agent. The formation of CuNPs was confirmed by ultraviolet-visible absorption spectroscopy (UV-Vis) at the wavelength range of 500-600 nm. The optimized conditions for the synthesis of CuNPs using CCP extract as a reducing agent were determined by the volume ratio of Cu(NO 3) 2 solution/ CCP extract of 3.5/1.5, stirring rate of 300 rpm, pH solution of 7.5, the temperature of 75 °C and the synthesis duration within 180 min. At these conditions, the X-ray diffraction result revealed a face-centered cubic structure of zero-valent copper with a highly crystalline and an average size of 34.4 nm. Fourier transform infrared spectroscopy result confirmed the presence of flavonoids, polyphenolic, and alkaloids components in CCP extract which can act as the reducing and stabilizing agents for CuNPs formation. At the optimized synthetic conditions, CuNPs loaded on various supports (Al 2 O 3 , CeO 2 , and TiO 2) were prepared following the same protocol and then applied for catalytic deep oxidation of aromatic hydrocarbons (AHs). Among them, CeO 2 was the best support in AHs deep oxidation, and the sample of 7.5Cu-Ce (7.5 wt% of CuNPs supported on CeO 2) was the most efficient. Compared with 5Cu-Ce and 10Cu-Ce, the 7.5Cu-Ce sample exhibited a higher benzene conversion at a low temperature (275-325 °C) and reached the full conversions of benzene, toluene, ethylbenzene, and xylene (BTEX) to carbon dioxide and water vapor below 450 °C. Furthermore, the 7.5Cu-Ce sample showed great stability for such reactions at 300 °C as proven by the unchanged conversions of BTEX during 48 h.

In this report, red-emitting alumina nanophosphors doped with Mn 4+ and Mg 2+ (Al 2 O 3 :Mn 4+ , Mg 2+ ) are synthesized by a hydrothermal method using a Pluronic surfactant. The prepared samples are ceramic-sintered at various temperatures. X-ray diffraction shows that Al 2 O 3 :Mn 4+ , Mg 2+ annealed at 500 °C exhibits a cubic γ-Al 2 O 3 phase with the space group Fd3m-227. The tetragonal δ-Al 2 O 3 and rhombohedral α-Al 2 O 3 phase is obtained at 1000 and 1300 °C, respectively. Cube-like nanoparticles in a size of ∼40 nm are observed for the alumina heated at 500−1000 °C. The size and red-emitting intensity of the phosphors remarkably increased with annealed temperature ∼1300 °C. Emission spectra of the phosphors show strong peaks at 678 and 692 nm due to 2 E g → 4 A 2 transitions of the Mn 4+ ion, under a light excitation of 460 nm. A strong zero-phonon line (ZPL) emission is observed in the luminescence spectra of δ-Al 2 O 3 :Mn 4+ , Mg 2+ at 298 K, whereas a weak one is observed in those of αand γ-Al 2 O 3 :Mn 4+ , Mg 2+ . The alumina phosphors exhibited an excellent waterproof ability during 60 days in water and good thermal stability in the range of 77−573 K. A warm-white light-emitting diode (WLED) fabricated using In x Ga 1−x N nanowire chips with Al 2 O 3 :Mn 4+ , Mg 2+ red-emitting nanophosphors presents a high color rendering index of ∼95.1 and a low correlated color temperature of ∼4998 K. Moreover, the current−voltage characteristic of the nanowire LEDs could be improved using Al 2 O 3 :Mn 4+ , Mg 2+ nanophosphors which is attributed to the increased heat dissipation in the nanowire LEDs.

Magnetic composite fabricated from polyaniline and Fe3O4-hydrotalcite (Pan/MHT) was successfully applicated for removal of methyl orange (MO) from wastewater. The structure and properties of Pan/MHT were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, vibrating sample magnetometer, and Brunauer-Emmett-Teller adsorption isotherm. Adsorption kinetic results indicated that the adsorption process followed pseudosecond-order kinetic model ( R 2 = 0.999 ), MO adsorption onto Pan/MHT was well described by Freundlich isotherm ( R 2 = 0.994 ), and the MO adsorption capacity of 2 Pan/MHT obtained the highest with Q e = 156.25   mg / g . Batch adsorption experiments were carried out using magnetic composite with the effects of initial MO concentration, solution pH, and adsorbent dosage. The results revealed that the magnetic Pan/MHT exhibited efficient adsorption of MO in the aqueous solution as a result of the affinity for organic dyes, microporous structure, and suitable surface area for adsorption (15,460 m2/g). The superparamagnetic behavior of Pan/MHT (with H c = 18.56   Oe , M s = 23.38 × 10 − 3   emu / g , and M r = 0.91 × 10 − 3   emu / g ) helps that it could be separated from the solution and performs as an economical and alternative adsorbent to removal and degrade azo dye from wastewater. Pan/MHT was also investigated to reuse after desorption of MO in 0.1 M HCl, and the results show that 2 Pan/MHT can be reused for 4 cycles with Q e = 79.66   mg / g .

Hydrotalcite intercalated with 2-benzothiazolylthio-succinic acid and graphene oxide (HT-BTSA/GO) was synthesized by co-precipitation method. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were used to characterize obtained HT-BTSA/GO. The release of BTSA from HT-BTSA/GO in NaCl solution at different concentrations was investigated by UV-Vis spectroscopy. HT-BTSA/GO was incorporated in solvent free epoxy coatings at concentration of 1 wt% and the corrosion protection of these coatings on carbon steel were examined by salt spray test and adhesion measurement. It was shown that GO and BTSA were intercalated in hydrotalcite structure and BTSA content was about 19.7 wt%. The release of BTSA from HT-BTSA/GO depended on chloride ion concentrations. After 72 h immersion in 0.1 M and 0.5 M NaCl solutions, the BTSA release were about 19.3 % and 61.0 % respectively. The presence of HT-BTSA/GO improved the corrosion resistance and adhesion of solvent free epoxy coatings. The corrosion protection performance of coatings containing HT-BTSA/GO was higher in comparison to the coating containing HT-BTSA.