Adsorption behavior of methylene blue dye onto surface modified Strychnos potatorum seeds

Abstract

Kinetic, mechanism, equilibrium, and thermodynamic behavior of adsorption of methylene blue (MB) dye onto surface modified Strychnos potatorum seeds (SMSP), in an aqueous solution were studied. Batch adsorption experiments were carried out to analyze the effect of initial solution pH, adsorbent dose, contact time, initial MB dye concentration, and temperature on the removal of MB dye. The kinetics of MB dye adsorption onto SMSP follows a pseudo‐second order kinetic model. The adsorption of MB dye onto SMSP was found to be controlled by both surface diffusion and pore diffusion. The diffusivity values were calculated from Boyd kinetic and Shrinking Core Model for varying initial MB dye concentration from 50 to 250 mg L−1. The adsorption equilibrium data were fitted to different adsorption isotherm models such as Langmuir, Freundlich, and Dubinin‐Radushkevich. The equilibrium data fitted best with the Freundlich adsorption isotherm model, which indicates multilayer adsorption of MB dye onto SMSP. The maximum monolayer adsorption capacity estimated with Langmuir isotherm model was 78.84 mg of MB dye molecules per gram of SMSP. Thermodynamic studies showed that the adsorption of MB dye onto SMSP follows an exothermic process. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 624–632, 2013

Adsorptive removal of Pb(II) ions from polluted water by newly synthesized chitosan–polyacrylonitrile blend: Equilibrium, kinetic, mechanism and thermodynamic approach

“…The adsorption isotherm parameters, correlation coefficient (R 2 ) values and error values were estimated by using this software directly by fitting the adsorption equilibrium data to the different adsorption isotherm models. The amount of Pb(II) ions adsorbed onto chitosan/PAN at time t (q t , mg/g) was found out by using the following mass balance equation (Kumar et al, , 2010Kumar, 2014;Senthamarai et al, 2013):…”

“…The amount of Pb(II) ions adsorbed onto chitosan/PAN at equilibrium time (q e , mg/g) was found out by using the following mass balance equation (Kumar et al, , 2010Kumar, 2014;Senthamarai et al, 2013):…”

“…All the experimental studies were done in duplicates. The percentage removal of Pb(II) ions can be calculated by using the following equation (Kumar et al, , 2010Kumar, 2014;Senthamarai et al, 2013):…”

“…The treatment methods like evaporation, ion exchange, adsorption, flocculation, electrodialysis, solvent extraction, coprecipitation and chelation therapy are the important unit operations for the removal of lead metals from the water/wastewater (Pal et al, 2014). Among these methods, the adsorption process was treated as a most widely used and recommended method for the removal of heavy metals because of its higher efficiency and energy economy for the large scale operations Senthamarai et al, 2013). Chitosan is a linear polysaccharide composed of ␤-(1,4)-2-amino-2-deoxy-d-glucopynarose units, a derivative of chitin, found abundant in nature has many fascinating properties like biodegradable, biocompatible, bioadsorptive, hydrophilic and is readily soluble in dilute acids (Bansal et al, 2011;Parida et al, 2011;Dutta et al, 2004;Zhang et al, 2002;Tripathi et al, 2009).…”

Effective and Selective Sorption of Iodide by Thin Film of Multilayered MnO2 Intercalated with Cationic Surfactants

“…18 The n values larger than 1 indicate that the sorption is a physical process. 19 In summary, we first developed a thin-film iodide sorbent consisting of multilayered MnO2 intercalated with surfactant molecules, which presents a maximum sorption capacity of over 200 mg/g, even in the presence of salts. This film can be fabricated on conducting substrates with a large surface area and flexibility.…”