Abstract
The quantitative kinetic and equilibrium adsorption parameters for chlorure de méthylrosaniline (gentian violet, crystal violet) removed by commercial activated carbon were studied by UV–visible spectroscopy.Activated carbon with a high specific surface area 1250 m2/g was characterized by the Brunauer, Emmett et Teller (BET) method and the zero charge point pH (pzc). The adsorption properties of both activated carbon with gentian violet were conducted at variable stirring speed 100–700 trs/min, adsorbent dose 1–8 g/l, solution pH 1–14, initial gentian violet concentration 5–15 mg/l, contact time 0–50 min, and temperature 299–323 K using batch mode operation to find the optimal conditions for a maximum adsorption. The adsorption mechanism of gentian violet was studied using the pseudo-first-order, pseudo-second-order, and Elovich kinetic models. The adsorption kinetics was found to follow a pseudo-second-order kinetic model with a determination coefficient (R2) of 0.999. The Weber–Morris diffusion model was applied for the adsorption mechanism. The equilibrium adsorption data of gentian violet were analyzed by the Langmuir, Freundlich, Elovich, and Temkin models. The results indicate that the Langmuir model provides the best correlation ( qmax = 22.727, 32.258 mg/g at 26 and 40°C, respectively). The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters, i.e. free energy (Δ G° = − 2.30 to −5.34 kJ/mol), enthalpy (Δ H° = 36.966 kJ/mol), entropy (Δ S° = 0.131 kJ/mol K), and activation energy ( Ea) 40.208 kJ/mol of gentian violet adsorption. The negative Δ G° and positive Δ H° indicate that the overall adsorption is spontaneous and endothermic in nature.
Highlights
Water pollution is one of the most undesirable environmental problems in the world and requires urgent solutions
The specific surface area was determined by the BET equation (Figure 3) while the external surface area, micropore area, and micropore volume were calculated by the t-plot method
The adsorption capacity of Gentian violet (GV) increased with raising the initial dye concentration, time, and pH; the optimized pH for adsorption was 11
Summary
Water pollution is one of the most undesirable environmental problems in the world and requires urgent solutions. Most of them can be eliminated by conventional methods, the concentration of toxic substances remaining in water after treatment may in many cases exceed the permissible limit (Benjelloun et al, 2016) They are mainly organic substances such as dyes released in large quantities by the textile industry and are responsible for the toxicity, odor, unpleasant taste, and water color, causing degradation of water quality and subsequent disappearance of aquatic life. There are several methods available for color removal from waters such as membrane separation, aerobic and anaerobic degradation using various microorganisms, chemical oxidation, coagulation and flocculation, reverse osmosis, and fungal decolorization (Dabrowski, 2001) Some of these techniques are effective but have some limitations such as excess amount of chemical usage, accumulation of concentrated sludge that has serious disposal problems, and lack of effective color reduction (Orthman and Hy and Lu Gq, 2003).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
