Chitosan coated biomass waste-based magnetic hydrogel beads for the removal of methylene blue

Abstract

Due to developing technology and increasing population, human needs have increased, and textile activities have gained momentum. Many synthetic dyestuffs are used to meet the needs in this field. In this study, a cheap, useful, innovative, environmentally friendly and sustainable adsorbent was developed for the removal of Methylene Blue(MB), which is one of the dyes that is harmful to the environment. In the cultivation of fruit trees, in addition to the product, very high amounts of by-products/waste (garbage, branches, bark, leaves, etc.) are produced. In this direction, fig tree wastes were immobilized with chitosan, made magnetic, and MB adsorption on the developed adsorbent was examined in a batch system. Glutaraldehyde was used as crosslinker. Characterization of synthesized glutaraldehyde cross-linked chitosan-coated magnetic vegetable waste composite beads (g-CMBW) was carried out by SEM, EDX, FTIR and XRD. In the study, the effects of temperature (25–55 °C), pH (3.0–8.0), initial MB concentration (10–250mg/L), contact time (5–360min) and the amount of adsorbent (2–10 g/L) on MB adsorption with g-CMBW were examined. The optimum conditions obtained were determined as pH 6.0, temperature 25 °C, adsorbent amount 6 g/L, and contact time 120 min. The maximum adsorption capacity in MB removal using g-CMBW composite beads was calculated as 103.1 mg/g according to the Langmuir isotherm model. The temperature studies showed that the adsorption capacity decreased with increasing temperature, showing that the system was exothermic. In light of these results, it was determined that there are new promising adsorbents of natural origin, with higher adsorption capacity, lower cost, and alternatives to commercially used adsorbents in the removal of MB from aqueous media.

NOVELTY STATEMENT

In this study, we developed a renewable magnetic composite bead as a low-cost pioneer based on a new sustainable biopolymer using chitosan and plant waste. The novelty of this work is based on the development of a new composite adsorbent that can be synthesized in a fast, simple, and environmentally friendly method, not requiring expensive reagents or complex equipment. Another innovation is that methylene blue, a common micropollutant, can be easily removed from polluted water using simple biowaste-based adsorbents by adopting appropriate procedures. It exhibited higher micropollutant adsorption performance compared to most other adsorbents. These results showed that it could be a very effective adsorbent for methylene blue removal from aqueous media.

Keywords:

• Biowaste
• chitosan
• glutaraldehyde
• nano Fe₃O₄

Authors' contributions

Şerife Parlayıcı: Supervision, Writing, Visualization, Funding Review and Editing. Aslı Aras: Investigation, Experimental studies, Data curation.

Disclosure statement

No potential conflict of interest was reported by the author(s).