Bio-Based Activated Carbons for Wastewater Remediation

This chapter presents a comparative study between two bio-based activated carbons produced from Saponaria officinalis and Rhus pentaphylla , applied respectively to the removal of organic dyes [methylene blue (MB), methyl red (MR)] and metal ions (Cd(II)) in aqueous solution. The preparation conditions were optimized using response surface methodology (RSM), resulting in materials with high porosity and strong adsorption capacity. Physicochemical characterization [Brunauer–Emmett–Teller (BET), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), point of zero charge (pHpzc)] enabled the structure of the adsorbents to be linked to their performance. The results showed that dye adsorption follows pseudo-second-order kinetics and fits the Langmuir model, while Cd(II) adsorption is better described by pseudo-first-order kinetics and a Freundlich isotherm. The adsorbent derived from Saponaria officinalis had a maximum capacity of 74.96 mg g −1 for MB, while that derived from Rhus pentaphylla reached 68.11 mg g −1 for Cd(II). A comparative analysis with other activated carbons derived from biomass highlights the good compromise between efficiency, production cost, and environmental sustainability. These results underscore the potential of these materials for decentralized wastewater treatment applications.