![Sample our Earth Sciences journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5930/TOC-Subject-Sample-2021-Earth-Sciences.jpg"})
ABSTRACT
The aim of this study was to establish the bark of Eucalyptus tereticornis L. (EB) as a low cost bio-adsorbent for the removal of imidacloprid and atrazine from aqueous medium. The pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich and intra-particle diffusion (IPD) models were used to describe the kinetic data and rate constants were evaluated. Adsorption data was analysed using ten 2-, 3- and 4-parameter models viz. Freundlich, Jovanovic, Langmuir, Temkin, Koble–Corrigan, Redlich–Peterson, Sips, Toth, Radke–Prausnitz, and Fritz-Schluender isotherms. Six error functions were used to compute the best fit single component isotherm parameters by nonlinear regression analysis. The results showed that the sorption of atrazine was better explained by PSO model, whereas the sorption of imidacloprid followed the PFO kinetic model. Isotherm model optimization analysis suggested that the Freundlich along with Koble–Corrigan, Toth and Fritz-Schluender were the best models to predict atrazine and imidacloprid adsorption onto EB. Error analysis suggested that minimization of chi-square (χ2) error function provided the best determination of optimum parameter sets for all the isotherms.
Acknowledgments
The authors are thankful to Mr. Bappa Das, Division of Agricultural Physics, Indian Agricultural Research Institute, New Delhi 110012, India, for his critical suggestions.
Nomenclature
| Nomenclature | ||
| AFS | = | Fritz–Schluender equilibrium constant (L mg−1) |
| aKC | = | Koble–Corrigan parameter (Ln mg1-n g−1) |
| aR | = | Redlich–Peterson model constant (mg L−1)−g |
| aRP | = | Radke–Prausnitz model constant |
| aS | = | Sips equilibrium constant (L mg−1)βs |
| AT | = | Temkin isotherm equilibrium binding constant (L/mg) |
| bKC | = | Koble–Corrigan parameter (L mg−1)n |
| bT | = | Temkin isotherm constant |
| Cs | = | adsorbate monolayer saturation concentration (mg L−1) |
| g | = | Redlich–Peterson model exponent |
| KE | = | Elovich equilibrium constant (L mg−1) |
| KF | = | Freundlich isotherm constant (mg1-NF kg−1 LNF) |
| KJ | = | Jovanovic isotherm constant (L mg−1) |
| KL | = | Langmuir isotherm constant (L mg−1) |
| KRP | = | Redlich–Peterson model isotherm constant (L mg−1) |
| KS | = | Sips maximum adsorption capacity (mg kg−1) |
| KT | = | Toth equilibrium constant |
| n | = | number of data points |
| nF | = | adsorption intensity |
| p | = | number of fitted parameters |
| Q0 | = | monolayer coverage capacity (mg kg−1) |
| qe,avg | = | average of the observed concentrations |
| qe,calc | = | calculated adsorbate concentration at equilibrium (mg kg−1) |
| qe,meas | = | measured adsorbate concentration at equilibrium (mg kg−1) |
| qm | = | theoretical isotherm saturation capacity (mg kg−1) |
| qs | = | theoretical isotherm saturation capacity (mg kg−1) |
| R | = | universal gas constant (8.314 J mol−1K−1) |
| rR | = | Radke–Prausnitz isotherm model constant |
| tT | = | Toth model exponent |
| w | = | weight factor |
| αFS | = | Fritz–Schluender model exponent |
| βFS | = | Fritz–Schluender model exponent |
| βR | = | Radke–Prausnitz isotherm model exponent |
| βS | = | Sips isotherm model exponent |