Removal of Toxic Malachite Green Dye Using Miscellaneous Agro-waste Derived GO: Isotherm and Kinetic Modelling

Abstract

Graphene oxide (GO) is an advanced material with copious applications in electronics, energy, storage and environmental remediation. Traditional approach of making GO from graphite can be resource intensive and ecologically challenging. GO is fabricated in the present study from agricultural wastes and subsequently used in removing the malachite green (MG) dye out from water. The fabrication method involves two steps of carbonization and a modified Hummer’s method. FTIR, BET, FESEM, HRTEM and Raman spectroscopy were conducted on the GO. The outcomes of these characterization analysis revealed the mesoporous nature of obtained GO with flaky morphology containing multiple oxygen functionalities on its surface. Batch studies revealed the high efficiency of the fabricated GO for the elimination of MG. The sensitivity of the adsorption process towards initial dye concentration, time of contact, amount of adsorbent and pH were also investigated. Under optimized conditions of 2g/L GO, 20 ppm of MG and at contact time of 60 mins, adsorptivity reached a maximum of 18.98 mg/g. Best fitting models were the Langmuir and pseudo second order. The high removal efficiency along with favorable prospects reveal the agro-waste derived GO as a potential material for the eradication of dyes from the wastewater.

Keywords

• graphene oxide
• agricultural waste
• malachite green
• dyes
• adsorption