Experimental Design, Equilibrium Modeling and Kinetic Studies on the Adsorption of Methylene Blue by Adsorbent: Activated Carbon from Durian Shell Waste

Abstract

For the first time, activated carbon from a durian shell (ACDS) activated by H2SO4 was successfully synthesized in the present study. The fabricated ACDS has a porous surface with a specific surface area of 348.0017 m2·g−1, average capillary volume of 0.153518 cm3·g−1, the average pore diameter of 4.3800 nm; ash level of 55.63%; humidity of 4.74%; density of 0.83 g·cm−3; an iodine index of 634 mg·g−1; and an isoelectric point of 6.03. Several factors affecting Methylene Blue (MB) adsorption capacity of ACDS activated carbon was investigated by the static adsorption method, revealing that the adsorption equilibrium was achieved after 90 min. The best adsorbent pH for MB is 7 and the mass/volume ratio is equal to 2.5 g·L−1. The MB adsorption process of ACDS activated carbon follows the Langmuir, Freundlich, Tempkin, and Elovich isotherm adsorption model, which has determined the maximum adsorption capacity for MB of ACDS as qmax = 57.47 mg·g−1. The MB adsorption process of ACDS follows the of pseudo-second-order adsorption kinetic equation. The Weber and Morris Internal Diffusion Model, the Hameed and Daud External Diffusion Model of liquids have been studied to see if the surface phase plays any role in the adsorption process. The results of thermodynamic calculation of the adsorption process show that the adsorption process is dominated by chemical adsorption and endothermic. The obtained results provide an insight for potential applications of ACDS in the treatment of water contaminated by dyes.

Speciation of Hexavalent Chromium in Aqueous Solutions Using a Magnetic Silica-Coated Amino-Modified Glycidyl Methacrylate Polymer Nanocomposite

“…The IPD plot ( Figure S1a ) indicates three diffusion stages: boundary layer diffusion, intraparticle diffusion, and equilibrium stage, where IPD slows down [ 42 ]. However, all three straight lines of the fitting curve do not pass through the origin, indicating that intraparticle diffusion is not the only rate-controlling step of chromium sorption.…”

Preparation of Reusable Porous Carbon Nanofibers from Oxidized Coal Liquefaction Residue for Efficient Adsorption in Water Treatment

“…The adsorption isotherm can reflect the equilibrium state of the adsorbate combined with the adsorbent in solution, further illustrating the adsorption mechanism of ARCNF [ 7 ]. The effects of different initial quality concentrations of the five dyes on the adsorption performance at a contact time of 72 h are shown in Figure S4 .…”

“…In order to simulate the salinity variation of organic dyes in real wastewater, the effect of ionic strength on ARCNF adsorption during the adsorption process was explored by setting different salinity gradient (10–50‰) [ 7 ]. As shown in Figure 8 b, there was basically no significant change in the adsorption of the four cationic dyes by the ARCNF during the gradual increase of ionic strength, further demonstrating the ability of ARCNF is able to maintain a high adsorption capacity in different ionic strength environments.…”

“…Synthetic dyes with a high output and low cost have arisen in response to the demands of human life, which have steadily gained acceptance and become widely used [ 4 , 5 , 6 ]. However, the direct discharge of wastewater contaminated by dyes has caused serious environmental problems [ 7 ]. Most dyes with complex aromatic structures are long-lasting in the nature and difficult to decompose, which is extremely dangerous for both human health and the environment [ 8 ].…”

Two New 1D Supramolecular Compounds Based on PbI2 for Efficient Iodine Capture

“…Langmuir’s isothermal adsorption model is a single molecular layer adsorption model, and Freundlich’s isothermal adsorption model is a multi-molecular layer adsorption model. In this experiment, two models were fitted according to the iodine adsorption experiment data of compound 1 : Langmuir (5) and Freundlich (6) isotherm adsorption model [ 49 ]. where q m is the maximum adsorption capacity (mg·g −1 ) of the adsorbent; K 1 is the Langmuir adsorption constant (L·mg −1 ); K 2 is the Freundlich adsorption constant (g·mg −1 ·min −1 ); n is a constant that characterizes the surface heterogeneity, and constant is always greater than 1.…”