Utilization of barks of Araucaria columnaris: Preparation of activated carbon/clay composite beads and adsorptive treatment of phenolic wastewater

Abstract

The powdered form of carbon has several technical, handling, transportation, and health-related disadvantages, but careful transformation of powdered carbon into a technically favorable shaped structure can increase the practicality of this green material. This study presents the preparation of activated carbon from Araucaria columnaris bark with one-step activation and its fabrication into a spherical carbon/clay composite using a natural binder (Montmorillonite). The structure and surface of prepared activated carbon and its composite material were explored with SEM, ATR-FTIR, Surface area, and porosity measurements. The post-fabrication change in adsorption properties was investigated for phenol adsorption in light of the change in physicochemical properties. Under optimum conditions, the carbon (activated at 650 °C) and its composite adsorb about 132.28 and 80.52 mg·g−1of phenol, respectively. The thermodynamics and kinetics of adsorption on these materials were investigated with different models. The adsorption rate of composite (1.25 ×10−3 g·mg−1min−1) is twice that of activated carbon, and its adsorption enthalpy also increased to − 30.02 kJ·mol−1. The regeneration and reusability studies show that the composite retains the structural advantages of activated carbon and improves its reusability by 8.5%. The experiments with synthetic wastewater indicate that Araucaria columnaris-based activated carbon is an efficient adsorbent for wastewater treatment, and its reusability can be further improved with its fabrication into carbon/clay composite beads.