Microwave-synthesized and Fenton-functionalized Pinus sylvestris bark activated carbon/metal oxides for the effective uptake of tetracycline and congo red dye

Abstract

The quest for the accessibility to clean water all over the world has become a serious global challenge that threatens the survival of humans and the ecosystem as well. This has necessitated the need for the United Nations (UN) to highlight the provision and sustainability of clean water to the global populace as the sixth sustainable development goal (SDG) by the year 2030. In this vein, this global urge has spurred us to synthesize functionalized Pinus sylvestris bark activated carbon/metal oxides by microwave and Fenton technologies, for the removal of tetracycline and Congo red from aqueous solutions. These surfaces of the functionalized P. sylvestris bark activated carbon/metal oxides were characterized by Fourier-transform infrared spectrometry, thermogravimetry, field emission scanning electron microscopy, and the multi-point nitrogen adsorptiometry–desorptiometry, applying the Brunauer–Emmett–Teller and Barett–Joyner–Halenda techniques, which showed that diverse functional moieties were responsible for the uptake of tetracycline and Congo red from aqueous solutions. The experimental data best fit the pseudo-second order and Liu isotherm models, with a monolayer adsorption, $$ {q}_{\max_{Liu}} $$ of 148.253 mg g−1 for tetracycline and 127.221 mg g−1 for Congo red at 328 K. Thermodynamic studies revealed that all the adsorption reactions were spontaneous. These adsorbents showed promising potential for the cleanup of water and wastewaters with pharmaceuticals and industrial dyes matrix.