Equilibrium, kinetic and thermodynamic adsorption studies of organic pollutants from aqueous solution onto CNT/C@Fe/chitosan composites

Abstract

The adsorption of organic pollutants, including dyes (methylene blue (MB) and methyl orange (MO)), antibiotics (tetracycline (TC)), and organic arsenical compound (roxarsone (ROX)), has been studied on a new kind of CNT/C@Fe/CS nanocomposite. The effect of solution pH, contact time, and temperature on adsorption properties has been studied. The adsorption process follows the pseudo-second-order kinetic model very well, and equilibrium studies fit well with Langmuir, Freundlich, and Temkin adsorption isotherms. The maximum uptakes of MB, MO, TC and ROX on CNT/C@Fe/CS are found to be 111.1, 500.0, 125.0, and 142.9 mg g À1 , respectively. Parameters calculated from thermodynamic indicate that the adsorption process is exothermic, spontaneous and favorable. The removal of organic pollutants is obviously dependent on pH values and temperature. These results suggest that the CNT/C@Fe/CS nanocomposite could be effectively used for the removal of organic contaminants from wastewaters.

A Novel One-Pot Route for Large-Scale Synthesis of Novel Magnetic CNTs/Fe@C Hybrids and Their Applications for Binary Dye Removal

“…Among the available adsorbents, carbon nanotubes (CNTs) have been regarded as a promising and efficient adsorbent − due to their large specific surface area (SSA), porous nanostructure with a high π-electronic density, and ease of functionalization . However, the separation of nanosized CNTs has become a problem because of their nanotoxicity , and secondary pollution after adsorption.…”

A Kinetic Uptake Study of Roxarsone Using Cross-Linked Chitosan Beads

“…This has raised concerns about arsenic contamination, especially in conversion of ROX to inorganic forms. Among the various remediation methods, adsorption-based removal is a promising strategy for the controlled uptake of inorganic and organic pollutants. − There are limited examples of adsorbents used for ROX removal that include carbon nanotubes, , chitosan composites, montmorillonite, metal oxides, , goethite composite, and metal–organic frameworks . By contrast, chitosan is an abundant and low-cost adsorbent that has been investigated mainly by batch techniques. , Poon et al reported batch equilibrium studies of glutaraldehyde (GA) cross-linked chitosan powders with ROX, where cross-linking was shown to enhance the adsorption capacity of ROX from 0.55 to 0.98 mmol/g .…”

Synthesis of magnetic nanocomposite microparticles for binding of chlorinated organics in contaminated water sources

“…These values are within error of reported saturation capacities for other engineered microplastics and magnetic composites developed for the adsorption of organic pollutants. [33,38] However, the B max of all the MNM systems are lower than those reported for other carbon-based materials, specifically a couple orders of magnitude lower than activated carbon. [39,40] The Langmuir adsorption coefficients obtained for the CMA MNMs, QMA MNMs, and PEG MNMs are 1.20, 1.28, and 1.84 nM, respectively.…”

“…This plateau is also known as the equilibrium monolayer capacity. [33] In order to understand the behavior of the synthesized microparticles, the Langmuir model is used to fit the experimental data and obtain the maximum adsorption capacity (B max ) and Langmuir adsorption coefficients (K D ) for each system (presented in Table 2). According to the values of nonlinear R 2 presented in Table 2, the Langmuir model provides a good fit to describe the systems and suggests the adsorption process is homogeneous and occurs as a monolayer, implying there is no interactions between PCB molecules bound at the surface of the MNMs.…”