Study on isotherm, kinetics, and thermodynamics of adsorption of crystal violet dye by calcium oxide modified fly ash

Abstract

The natural Fly ash modified with calcium oxide has been employed to eliminate the crystal violet dyestuff from the simulated solution. Herein, the effect of different physicochemical factors like primary dye concentration, sorption contact time, the quantity of the adsorbent, temperature, along with initial simulated solution pH, evaluated for illustrating the mechanism of adsorption. Furthermore, the equilibrium study was conducted, and equilibrium models like Langmuir, Freundlich, and Dubinin- Raduskevich (D-R) were fitted to obtain analytical results to endow with more insight into the process. The results acknowledged that the Langmuir model is well apt and suggests that the adsorption mechanism happens in a monolayer on the fly ash surface. Pseudo-first order, Pseudo-second order, and the intraparticle diffusion model evaluated, and the interpretation suggests the sorption method is obeying the Pseudo-second order and intraparticle diffusion model. The ascertained negative values of Gibbs free energy affirmed the unconstrained process for all symbiotic associations, and the obtained data 78.70 kJ mol<sup>–1</sup> enthalpy values manifested that exothermic mechanism was governing the reaction. The above assessment confirms the application of Calcium oxide pre-treated fly ash as a cheap adsorbent to eliminate the crystal violet dyestuff from the simulated solution.

Characterization of Ethyl Violet Adsorption on Used Black Tea Leaves from Aquatic Environment: Kinetic, Isotherm and Thermodynamic Studies

“…Such observations are in good agreement with earlier findings for the adsorption of same dye onto regenerated spent bleaching earth or the adsorption of methylene blue on kaolinite [19,46]. It is evident from the literature [47] that with increasing pH values, loss of H + ions occurs from the surface of adsorbent causes higher percentage of dye removal from aqueous solution at higher values of the pH.…”

Synthesis of potential bio-adsorbent from Indian Neem leaves (Azadirachta indica) and its optimization for malachite green dye removal from industrial wastes using response surface methodology: kinetics, isotherms and thermodynamic studies

“…The effluents of dyeing industries use highly colored compounds having high chemical and biological oxygen demand (Garg et al 2004). These dye containing effluents can harm the living systems of the natural water bodies as well as the human beings due to their carcinogenic, allergenic and toxic effect (Akar et al 2009;Chakraborty et al 2020). Since water is an indispensable part of our life (Halder et al 2016;Roy et al 2020), several physicochemical processes have been developed to reduce the impact of carcinogenic dyes on the environment.…”

Enhancing the removal efficiency of methylene blue in water by fly ash via a modified adsorbent with alkaline thermal hydrolysis treatment

“…One of them is coal FA that has been used to produce zeolite and geopolymers, further applied in environmental remediation such as wastewater treatment and air pollution treatment. 13,14 Specically, up to date, many reports have been carried out on using FA for the treatment of dye and textile wastewater, [14][15][16][17] heavy metal, [18][19][20] toxic gases, 21 and other organic matters. 22 However, original FA presents a low adsorption capacity; consequently, the original FA must be modied to improved adsorption ability.…”