Gerard Pierre Tchieta

The objective of the current work was to synthesize and characterize ferromagnetic activated carbon from peanut shells (PSs) and apply it for the degradation of methyl orange (MO) following the heterogeneous Fenton process. PSs were activated with phosphoric acid and potassium hydroxide at 1:1, 1:2, and 1:3 solid/liquid activation ratios and different concentrations (0.5, 1, and 1.5 M) and pyrolized at 500°C. Based on the iodine indexes, KOH-activated carbon adsorbents exhibited higher porosity than the H₃PO₄-activated adsorbents. KOH-activated carbon at a 1:3 activation ratio (iodine value 591 mg/g) was selected for magnetization using iron (II) ions and catalytic mineralization of MO dye. The ferromagnetic activated carbon (AC-PS@FeII) was characterized using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, and nitrogen-adsorption BET measurements. AC-PS@FeII contained ferromagnetite with a cubic spinel structure and a specific area of 181.96 m²·g^–1. AC-PS@FeII degraded MO with a degradation efficiency of 99.22% at pH 2, 4 g/L of catalyst dosage, and a 50-min contact time. The results of recyclability tests, using distilled water, revealed a slight decrease in degradation capacity after four runs, indicating that the developed catalyst was appreciably stable. The hetero-Fenton catalyst from peanut shells could be an ideal catalyst for treating wastewater contaminated with dyes as a path toward a circular economy.

A brief review has been herein done of technologies involved in the exploitation of lignin, in order to provide an introduction to the subject from the perspective of a fast technologically advancing economy. Lignocellulosic materials and biomass have historically been utilised from since time memorial, but a new conversation is emerging on the role of these materials in modern bioeconomies. This new discourse needs to help us understand how technologies for managing and processing lignocellulosic materials both as biosynthetic moieties, biogenic wastes or simply renewable biopolymer—both established and novel—should be deployed and integrated (or not) to meet developmental requirements of the sustainability paradigm. The world is caught in the middle of green technology advocating for more and more focus on renewable sources of manufacturing raw materials and that of the molecularly imprinted/synthesised or genetically engineered ones. The utilisation of lignins (from renewable sources) in both the industry as the base for the formulation of ionic liquids (with yet a wider industrial applications), and also is a potential scaffold material for functionally modified imprinted polymers (LCIPS) for the selective recovery of base metals and gold, respectively, evidently incorporates the bioeconomy aspirations.