Entrapment of distilled palmarosa (cymbopogon martinii) wastes in alginate beads for adsorptive removal of methylene blue from aqueous solution

This study described a preparation of a low-cost adsorbent by entrapment of palmarosa distillation wastes into alginate as supporting matrix and use of it for methylene blue (MB) dye removal from aqueous solution. Fourier transform infrared spectroscopy (FTIR) data of adsorbent confirms the entrapment for formation of composite beads. The effects of adsorption parameters (adsorbent dose, temperature, initial dye concentration, and pH) were investigated. Time to reach the equilibrium was dependent on dye concentration and it was 120 min for lower concentration and 240 min for higher concentration. The analysis of the kinetic data by pseudo-first-order and pseudo-second-order models displayed that MB adsorption followed pseudo-second-order model. The equilibrium data of MB adsorption were described by applying the Langmuir, Freundlich, and Temkin models. The observations from adsorption isotherms indicated that Langmuir model is the best fitted model and the maximum adsorption capacity (at the optimum pH 9.0) improved from 5.71 to 6.45 mg/g as the temperature increased from 298 to 328 K. The thermodynamic studies demonstrated that MB adsorption on to the adsorbent was spontaneous, feasible, and endothermic. Low desorption of the dyes from the adsorbent indicates that the dyes might have been chemisorbed on to the adsorbent surface. A single-stage batch adsorber was designed and quantity of adsorbent required for treating 1-10 L of stained water was determined based on the Langmuir isotherm model equation. Results indicate that the composite bead could be an alternative for relatively costly adsorbents used for remediation of MB dye bearing industrial effluents. (c) 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901-1907, 2018