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Ligno-cellulosic biomasses had been recognized for their potential use to produce chemicals and biomaterials. The current study focused on the use of a new cellulosic Robinia Pseudoacacia fiber and extracted lignin as adsorbents for methylene blue (a cationic dye). The biomaterials were analyzed using FT-IR spectroscopy, SEM, XRD, and TGA-DTA techniques. The surface of Robinia fibers was rough and porous. The crystallinity index (CrI) value for Robinia fibers was found to be 32%. The ability of the studied samples to remove methylene blue from water was assessed under the variation of time, pH, dye concentration, temperature, and NaCl concentration. The maximum adsorption capacity of methylene blue reached 191 mg/g for Robinia fibers and it achieved 22 mg/g for the extracted lignin (T = 20 °C, pH = 6, and time = 90 min). The adsorption data complied with the pseudo second-order kinetic model and both Langmuir and Freundlich isotherms. Based on these findings, the process suggested the occurrence of many physicochemical interactions between methylene blue molecules and the studied biomaterials. The adsorption mechanism was exothermic, non-spontaneous, and it was described by the decrease of the disorder. Adsorption results proved that Robinia fiber was an attractive candidate for the removal of cationic dyes from water. A low-cost and abundant Robinia Pseudoacacia fiber and its extracted lignin are characterized and further studied as adsorbents for cationic dyes under the change of the experimental conditions. [ABSTRACT FROM AUTHOR]

Thin films of Cu2O were deposited on ITO glass substrates by using the electrodeposition method. The prepared samples were annealed at different temperatures range varying from 200 to 350°C. Chemical, structural and optical properties of samples were studied using XRD, Raman spectroscopy, U-V–visible and photoluminescence spectroscopies. The results revealed that all samples at temperatures lower than 300°C are mainly single cubic Cu2O phase. However, after increasing the annealing temperature to 350°C, Cu2O films are partially oxidized and contain two phases of Cu2O and CuO. Raman results agree with the crystallite size results where the intensity of Raman peaks increases simultaneously with increasing grain size. The optical measurements showed that the band gaps values of the electrodeposited samples increase from 2.12 to 2.24 eV. Two optical gaps were observed at 1.58 and 2.26 eV for the sample annealed at 350°C which confirms the presence of two phases CuO and Cu2O. [ABSTRACT FROM AUTHOR]