Graphene oxide-based sorbents modified with waste orange peel biochar for Cd(II) removal from aqueous waste streams

Abstract

ABSTRACT Living organisms are at great risk from the highly toxic metal cadmium (II). It is not allowed to be in industrial effluent or drinking water that is dumped into cadmium-containing water bodies. It has been classified as a carcinogen by the IARC and the US EPA. Thus, it is essential to discover a practical and economical technique for removing cadmium from an aqueous solution. In the present work, a novel and easy-to-prepare component of graphene oxide/orange peel/chitosan composite (GO-OP-CS) was prepared and examined using various analytical techniques as a hybrid product with improved physicochemical properties and metal ion Cd(II) adsorption capabilities. The results showed that Cd (II) ion adsorption occurred initially fairly fast and that a pH of 6 was optimal for both adsorption and removal of Cd (II) ions. The thermodynamic analysis revealed that the adsorption of Cd(II) is spontaneous and exothermic. The experimental results showed that the functional groups present on the adsorbent surfaces (such as hydroxyl, carboxyl, epoxy, amine, and so on) led to the improvement of the Cd(II) metal’s ability to absorb. This novel composite exhibited a high adsorption capacity (qmax) of 537.63 mg/g. The results of the toxic Cd(II) sorption using the synthesized composite showed that its adsorption kinetics and sorption isotherm confirmed the pseudo-second-order and Langmuir models, respectively. The proposed method is also reliable for Cd(II) sorption for preconcentration and remediation before Cd testing from genuine samples, such as wastewater, digested tobacco, and e-battery samples.