Chemically treated kola nut pod as low-cost natural adsorbent for the removal of 2,4-dinitrophenol from synthetic wastewater: batch equilibrium, kinetic, and thermodynamic modelling studies

Abstract

Abstract:The feasibility of using chemically treated kola nut pod to remove 2,4-dinitrophenol from its aqueous solutions under batch mode was investigated. The results showed that biosorption of 2,4-dinitrophenol was dependent on initial concentration, contact time, pH, biosorbent particle size, biosorbent dosage, and temperature. The batch equilibrium biosorption data were analyzed by 2 two-parameter (Langmuir and Freundlich) and 2 three-parameter (Redlich-Peterson and Sips) adsorption isotherm models using linear and nonlinear regression methods. The Sips isotherm equation employing the parameter sets derived using the HYBRID/MPSD/ARE errors provided the overall best model to describe the biosorption data of the 2,4-dinitrophenol-kola nut pod system. The maximum monolayer biosorption capacity ( Qmax) was obtained to be 32.26 mg/g with linear regression and 30.10 mg/g with nonlinear regression. The biosorption kinetic data were fitted to 6 biosorption kinetic models using the linear regression method. The 6 kinetic models fitted well to the biosorption kinetic data; however, the pseudo-first-order kinetic model gave the best fit and the biosorption mechanism was controlled by film diffusion. The thermodynamic analysis indicates that the biosorption process was spontaneous, feasible, exothermic, and physical in nature. Thus, chemically modified kola nut pod has potential for application as an effective bioadsorbent for 2,4-dinitrophenol removal from wastewater.

Adsorption of Azo Dyes by a Novel Bio-Nanocomposite Based on Whey Protein Nanofibrils and Nano-clay: Equilibrium Isotherm and Kinetic Modeling

“…According to the interpretation of this three-stage process (Jiang et al, 2017; Lee, Lee, Chia, Tan, & Gan, 2014; Ngwabebhoh et al, 2016; Tang et al, 2012), the first stage (up to 60 minutes, 70% adsorption) is related to the diffusion of dye molecules from the bulk solution to the external surface of WPF/MMT. The second stage (up to 5 h, ~90% adsorption) can be attributed to intra-particle diffusion of dye molecules into the interior of WPF/MMT, and finally, the third linear stage is related to the equilibrium phase of the adsorption process and reflects the decrease in dye concentration (AGARRY & OGUNLEYE, 2014; Tang et al, 2012). Thus, it can be concluded that the adsorption data can be described with the intra-particle diffusion model.…”

Molecularly imprinted polymers for selective adsorption of quinoline: theoretical and experimental studies

“…Batch adsorption studies were performed on a Tecnal Shaker (TE-421) with a temperature control device adjusted for different temperatures (288.15, 298.15, 308.15 and 318.15 K). Quinoline solutions of 5.00 mL prepared at different concentrations (4,12,20,28,36,44,52,60,68,76 and 82 mg L À1 ) were placed in contact with 10.00 mg of MIPC or MIPT adsorbent in amber asks under constant stirring at 180 rpm for four hours.…”

“…Quinoline is one of the most powerful inhibitors of the HDT process due to poisoning of the catalysts. 4,5 Adsorption treatments using porous materials, such as zeolites, activated carbon, activated alumina, silica gel, kaolinite, and montmorillonite, are the preferred alternatives for the removal of these contaminants; however, they are not selective. 4,5 On the other hand, molecularly imprinted polymers (MIPs) are highly selective adsorbents because they are capable of forming complementary sites with the target molecule on their surfaces, which leads to the formation of specific cavities in the polymer network.…”

Preparation of Anion Exchange Resin Loaded with Ferric Oxide for Arsenic (V) Removal from Aqueous Solution

“…Freundlich adsorption isotherm can be applied for multilayer adsorption on heterogeneous surface with non-uniform distribution of adsorption heat [11], [12]. The linearity of Freundlich isotherm can be expressed by the following equation…”

“…Langmuir isotherm is based on monolayer adsorption on the active sites of adsorbent with a finite number of identical binding sites [11], [12]. ) where q e is the amount of As(V) adsorbed at equilibrium(mg/g), C e is the equilibrium As(V) concentration(mg/L), q m and b are Langmuir constants which represent the maximum adsorption capacity(mg/g) and the energy of adsorption, respectively.…”