Removal of pharmaceutical compounds from aqueous solution by novel activated carbon synthesized from lovegrass (Poaceae).

In this work, lovegrass (Cpa), an abundant grass of the Poaceae family, was employed as feedstock for the production of activated carbon in a conventional furnace using ZnCl2 as a chemical activator. The prepared material (Cpa-AC) was characterized by pH of the point of zero charges (pHpzc), Boehm's titration method, CHN/O elemental analysis, ATR-FTIR, N2 adsorption/desorption curves, and SEM. This carbon material was used for adsorption of acetylsalicylic acid (ASA) and sodium diclofenac (DFC). FTIR analysis identified the presence of O-H, N-H, O-C=O), C-O, and aromatic ring bulk and surface of (Cpa-AC) adsorbent. The quantification of the surface functional groups showed the presence of a large amount of acidic functional groups on the surface of the carbon material. The isotherms of adsorption and desorption of N2 confirm that the Cpa-AC adsorbent is mesopore material with a large surface area of 1040 m2 g-1. SEM results showed that the surface of Cpa-AC is rugous. The kinetic study indicates that the system followed the pseudo-second-order model (pH 4.0). The equilibrium time was achieved at 45 (ASA) and 60 min (DCF). The Liu isotherm model best fitted the experimental data. The maxima sorption capacities (Qmax) for ASA and DFC at 25 °C were 221.7 mg g-1 and 312.4 mg g-1, respectively. The primary mechanism of ASA and DFC adsorption was justified considering electrostatic interactions and π-π interactions between the Cpa-AC and the adsorbate from the solution.

Methylene blue biosorption from aqueous solutions by yellow passion fruit waste.

The yellow passion fruit (Passiflora edulis Sims. f. flavicarpa Degener) (YPFW) a powdered solid waste, was tested as biosorbent for the removal of a cationic dye, methylene blue (MB), from aqueous solutions. Adsorption of MB onto this low-cost natural adsorbent was studied by batch adsorption at 25 degrees C. The effects of shaking time, biosorbent dosage and pH on adsorption capacity were studied. In alkaline pH region the adsorption of MB was favorable. The contact time required to obtain the maximum adsorption was 48 h at 25 degrees C. Four kinetic models were tested, being the adsorption kinetics better fitted to pseudo-first order and ion exchange kinetic models. The ion exchange and pseudo-first order constant rates were 0.05594 and 0.05455 h(-1), respectively. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Redlich-Peterson isotherm models. Taking into account the analysis of the normal distribution of the residuals (difference of q(measured)-q(model)), the data were best fitted to Sips isotherm model. The maximum amount of MB adsorbed on YPFW biosorbent was 44.70 mg g(-1).

Eragrostis plana Nees as a novel eco-friendly adsorbent for removal of crystal violet from aqueous solutions.

Eragrostis plana Nees (EPN) was used as new and eco-friendly adsorbent for the removal of crystal violet dye (CV) from aqueous solution. Specific surface area (BET), scanning electron microscopy (SEM), infrared spectroscopy (ATR-FTIR), point of zero charge (pHPZC), and modified Boehm titration method were used to characterize the EPN material. The effects of initial pH of solution, adsorbent mass, contact time and initial dye concentration, and temperature were studied in batch adsorption mode. Kinetic data were evaluated by pseudo-first-order and pseudo-second-order models. The result exhibited that pseudo-second-order model well described the adsorption kinetics of CV onto EPN. Langmuir, Freundlich, and Sips isotherm models were used for analysis of the isothermal data. The equilibrium data of adsorption of CV onto EPN was better fitted with the Sips isotherm. Based on the Sips isotherm model, the maximum adsorption capacity was 76.20 ± 1.20 mg g-1 at 333 K. A high desorption of CV from EPN was obtained using 1.00 mol L-1 of CH3COOH as eluent. The thermodynamic data indicated that the adsorption was spontaneous, endothermic, and physical process. EPN can be used as alternative adsorbent to remove CV from aqueous solution.