Low-cost magnetic carbons-based rubber seed husks materials for highly efficient removal for reactive black 5 and reactive blue 19 textile dyes from wastewater

Abstract

Suitable and cost-effective magnetic carbons (CA-HP-FeII/FeIII) were prepared from biobased rubber seed hull materials by chemical activation with phosphoric acid and ferric ions. Physical and chemical properties of the materials were investigated using XRD, FT-IR spectroscopy, SEM analysis, N2 adsorption/desorption, Raman analysis and EDX/EDX-mapping. Magnetic carbons were used to remove reactive black 5 and reactive blue 19 textile dyes in aqueous solution. The pH of the solution, the mass of magnetic carbons and the initial concentration of dyes were investigated. The activated carbon obtained has a surface area of 110 m2.g−1 with an amorphous structure. A maximum removal efficiency of 76.27% for reactive black dye 5 and 94.44% for reactive blue dye 19 was achieved, at optimum pH 2. Kinetic studies showed that non-linear Elovich's model accurately describes the adsorption mechanism, which assumes an energetically heterogeneous magnetic carbon surface. The two-parameter non-linear models for the adsorption isotherms revealed that the adsorption of reactive black 5 and reactive blue 19 on CA-HP-FeII/FeIII satisfied the Temkin isotherm, demonstrating the exothermic nature of the adsorption process. The three-parameter adsorption isotherm reveals that the magnetic carbons have a heterogeneous surface with energetically diverse adsorption sites. Magnetic carbons were found to be attractive and suitable for the purification of these dyes.