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AbstractIn this report we present a simple synthesis of a nickel-based metal organic framework (MOF-Ni) at the room temperature using a solution of dimethylformamide (DMF), ethanol and distilled water. The MOF-Ni synthesized in various solvents displayed numerous different properties and advantages over other materials including easy synthesis procedure, good crystallinity, rigidity, and robust chemical stability. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) were employed to analyze the as-synthesized MOF-Ni. The as-obtained MOF-Ni was used to investigate its adsorption kinetics of red telon dye (RTL) molecules. The effects of time (30–270 min), initial RTL concentration (20–300 mg/L), adsorbent dose (2–50 mg), solution pH (2–12), and temperature (10–80 °C) were investigated. The pseudo-first order rate equation was able to provide the best description of the adsorption kinetics data in the studied time scale. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms, and the isotherm constants were also determined. Dye adsorption turned out to strongly depend on pH, and a low pH was found to increase the amount of adsorbed dyestuff. Compared with other samples, MOF-Ni synthesized in (DMF ​+ ​C2H5OH ​+ ​H2O) had a significantly enhanced adsorption ability for RTL dye. The MOF-Ni high adsorption capacity for RTL dye was attributed to the electrostatic attraction/repulsion phenomena. Moreover, MOF-Ni showed an improved stability at 370, 417, and 423 °C temperatures. The results obtained through our experiments suggested that our porous MOF-Ni microstructures synthesized in DMF ​+ ​C2H5OH ​+ ​H2O have potential applications for treating wastewaters containing RTL dyes. [ABSTRACT FROM AUTHOR]

• Activated carbons were synthesized from coffee waste by chemical activation method. • The activated carbons were successfully tested for amoxicillin adsorption. • The adsorption capacity of our adsorbent was compared to a commercial activated carbon. • The reusability of the prepared activated carbons has been tested at three cycles by a chemical method. • Adsorption was found to be thermodynamically spontaneous and endothermic. In the present study, we describe the synthesis of coffee waste activated carbon (SAC) as potential material for the amoxicillin (AMOX) removal from aqueous solution. The conditions for synthesizing SAC were an impregnation weight ratio of raw biomass to KOH equal to 1:2 followed by activation at 800 °C for 1 h. The FTIR analysis and Boehm titration showed that SAC has 1.7627 and 1.5414 m eq / g, respectively for acidic groups and of basic groups. The operating experimental parameters that govern the adsorption namely the temperature (288–318.16 K), intial pH (2.0–12.0), initial AMOX concentration C o (50–450 mg/L) and ionic strength were optimized. The adsorption isotherms were analyzed by various models. The experimental data were suitably matched to the Sips and Langmuir equations (R2 = 0.998). A Langmuir sorption capacity of 370 mg g−1 was determined, a value higher than that obtained on commercial activated carbon (CAC) employed for similarity purposes. The nature of the electrolyte was also examined with non-buffered AMOX solutions at different NaCl concentrations. The experimental results showed that AMOX adsorption is favored above pH 10. Otherwise, the absorption capacity is not influenced by the ionic strength of the electrolyte. The AMOX adsorption onto SAC was found to be exothermic and spontaneous under the operating parameters. The reusability of the adsorbent was tested by using appropriate chemical solvents and the results showed also that the sorption capacity decreases from 370 mg/g to 250 mg/g after four consecutive cycles. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, new activated carbons (ACs) from coffee grounds were synthesized using different impregnation ratios of KOH. The obtained materials were characterized by the Fourier Transform Infrared Spectroscopy (FTIR), Boehm titration, N 2 adsorption-desorption isotherms and Scanning Electron Microscopy (SEM). The results of the FTIR and Boehm titrations indicate the presence of many functional groups on the ACs surface. Basic groups determined from the Boehm titration show a strong dependence on the impregnation ratio. N 2 adsorption-desorption isotherms show an augmentation of the adsorbed volume for high impregnation ratios. This is due to the well-developed microporosity which increases with increasing the impregnation ratio. The maximal specific surface area obtained from the BET measurement was found to be 1778 m 2 g −1 for an impregnation ratio of 36 mmol of KOH/g of precursor. The prepared ACs were tested for their removal efficiency for the phenol (Ph) and methylene blue (MB) molecules. Batch adsorption tests were performed and the effects of contact time, initial concentration and temperature were investigated. The adsorption kinetic parameters were determined by fitting with the pseudo-first and pseudo-second order models to the experimental data. An evaluation of both the correlation coefficients (R 2 ) and the adsorbed amount per unit mass of adsorbent (Q e ) at equilibrium indicates that Ph and MB adsorption by ACs are satisfactorily described by the pseudo-second order model. The experimental adsorption equilibrium data were fitted to the Langmuir and Freundlich models. The effect of temperature on the adsorption was studied and the thermodynamic parameters: enthalpy (ΔH°), entropy (ΔS°) and free energy (ΔG°) were determined for each molecule. The adsorption for Ph and MB was found to be thermodynamically spontaneous (ΔG° < 0), although it was exothermic (ΔH° < 0) for Ph and endothermic (ΔH° > 0) for MB. [ABSTRACT FROM AUTHOR]