Comparative Isotherms Studies on Adsorptive Removal of Congo Red from Wastewater by Watermelon Rinds and Neem-Tree Leaves

Abstract

Equilibrium adsorption studies for detoxification of Congo Red (CR) dye from single component model wastewater by powdered watermelon rinds and neem leaves adsorbents were carried out with the view to test the applicability of the adsorption process to Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Harkins-Jura isotherm models. The values of correlation coefficient, R 2 (0.9359-0.9998), showed that all the experimental data fitted the linear plots of the tested isotherm models. Dubinin-Radushkevich's monolayer maximum adsorption capacity qD (20.72-26.06 mg/g) is better than Langmuir's qm (18.62-24.75 mg/g) for both adsorbents with the capacities higher for adsorption on watermelon rind than on neem leaves. Values of Langmuir separation factor (RL) suggest unfavourable adsorption processes (i.e. chemisorption) of the dye on both the adsorbents, while Freundlich constant (nF) indicates unfavourable process only for CR adsorption onto neem leaves. The Dubinin-Radushkevich's mean free energy of adsorption, (0.29-0.32 kJ/mol), suggests physical adsorption processes. Values for Temkin's heat of adsorption, bT (-0.95 to 0.74 kJ/mol), also show physical adsorption process.

Photocatalytic degradation and photo-Fenton oxidation of Congo red dye pollutants in water using natural chromite—response surface optimization

“…Dyes are aromatic compounds used for coloring applications (Ibrahim and Sani 2010). Dyes are widely used in several modern industries such as textile, leather, paper, printing, paint, pigments, rubber and plastic.…”

Equations Adsorption Isotherms for Biuret on Soils, Paper and Cortex Plant Application of the Freundlich, Langmuir, Temkin, Elovich, Flory-Huggins, Halsey, and Harkins-Jura

“…To have an insight into the adsorption behavior of biuret on the soils, paper and cortex plant samples, and to gain the optimal fitting of theoretical model, the experimental data from batch experiment were analyzed using Distribution Coefficient and seven parameter isotherm equations, Freundlich, Langmuir, Temkin, Elovich, Flory-Huggins, Halsey, and Harkins-Jura, in which linear regression analysis was used to evaluate whether the theoretical models have better or worse fit for the experimental data [10]. The respective parameters of these isotherm models have been enumerated in (Table1, and 2).…”

Valorization ofAdenanthera pavoninaseeds as a potential biosorbent for lead and cadmium removal from single and binary contaminated system

“…FTIR spectra of the prepared biosorbent samples shows various vibrational frequencies due to various functional groups present in the biosorbent and is presented in Figure 2 ) and T is the absolute temperature in Kelvin (K) (Ibrahim & Sani, 2014). The D-R isotherm constants, q D and B D were calculated from the plot between ln q e and ε 2 .…”