Evaluation of single-component and multi-component adsorption of metronidazole, phosphate and nitrate on activated carbon from Prosopıs julıflora

By S. Manjunath, Mathava Kumar. Chemical Engineering Journal, 2018

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Abstract In this investigation, activated carbon was prepared from Prosopis juliflora (PJAC) and characterized using porosimetry, scanning electron microscope (SEM-EDX), Elemental analysis (CHNS), Fourier Transmission-Infrared Radiation (FTIR) and X-ray Diffraction (XRD) analysis. Subsequently, PJAC was used in single-component (metronidazole (MNZ), phosphate (PO43−) and nitrate (NO3−)) and multi-component (MNZ:P:N) adsorption systems. As a first step, single-component batch adsorption experiments, i.e. kinetic and equilibrium studies, were conducted at controlled conditions (30 °C) and outcomes were used to find out the rate constant and maximum adsorption capacity ( q m ). The pseudo-second-order kinetic model was found to well represent the removals of MNZ, PO43− and NO3− on PJAC. Among the five isotherm models used, Langmuir isotherm model has predicted q m of PJAC for MNZ (17.33 mg/g), PO43− (13.55 mg/g) and NO3− (10.99 mg/g) with good correlation. In addition, the thermodynamic parameters have shown that adsorption of MNZ, PO43− and NO3− was non-spontaneous, endothermic and increased randomness in nature. In order to quantify the competitive adsorption of the multi-component system, i.e. MNZ, PO43− and NO3−, the batch experiments were conducted in the presence of all three compounds at a ratio of 1:2.5:5 at three different MNZ:P:N concentrations levels (0.1:0.25:0.5, 1:2.5:5 and 10:25:50 mg/L). The modified Langmuir competitive adsorption isotherm model was used to predict the effect of competitive adsorption. In the multi-component system, the maximum adsorption capacities of MNZ and NO3− were decreased by ∼34 and ∼2 times, respectively than single compound system; however, it was increased by ∼1.12 times for PO43−. Overall, the results indicate that PJAC could be used as a potential adsorbent for the removal of emerging pollutants and nutrients.

Subfields: Biomaterials, Industrial and Manufacturing Engineering, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/6b21eddee9cf9da0588e6218651eea06a3257973