The phosphorus used as fertilizer in agriculture is extracted from phosphate rocks, which after extraction reacts with sulfuric acid, releasing phosphoric acid, a raw material for the fertilizer industry. Studies point to a possible depletion of world reserves of phosphate rock in the next 50-100 years. A phosphorus scarcity is closely linked to global food security, given the dependence of soil fertilization to maintaining agricultural productivity within the current patterns of agribusiness. The application of fertilizers in soil and the sanitary sewers have been historically responsible for the larger eutrophication of water environments. In recent years, phosphorus has been seen as a finite resource and extremely important for the maintenance of the agricultural productivity. Therewith it is necessary investments to improve of fertilizers practices soils, safe technologies of organic waste reuse such as animal waste and phosphorus recovery, both released into water resource. Taking into account the depletion scenario of phosphorus deposits and eutrophication of water bodies, the water and phosphorus scarcity are among the most urgent environmental issues of the XXI century. Economic development, protection of public health, and maintenance of aquatic life are dependent of water availability and quality

In Brazil, a significant part of the biomass is unused, contributing to environmental pollution. The tannin industry commonly extracts tannins from the bark of Acacia mearnsii or black wattle, leaving a significant residue of 70% (w w⁻¹). This study investigates the conversion of black wattle bark into a porous carbonaceous material to efficiently remove organic pollutants. Using ZnCl₂ as a chemical activation reagent, the experiments varied the impregnation time, carbonization rates, and temperatures. Additional experiments aimed to increase the specific surface area (SSA). X-ray diffraction (XRD) analysis showed the formation and removal of ZnO, which increased porosity. Scanning electron microscopy (SEM) showed an irregular morphology with pores. Fourier-transform infrared (FTIR) spectroscopy indicated characteristic bands, and electron paramagnetic resonance (EPR) detected organic free radicals. The SSAs exceeded 1000 m² g⁻¹, averaging 1360 m² g⁻¹, with a maximum of 1525 m² g⁻¹. Micropores (1.4 nm) were consistent. The structure of the material and the high SSA suggest a potential for efficient removal of aromatic impurities by π–π interactions. This approach addresses the issue of biomass waste, provides a solution for environmental remediation, and represents a transformative strategy for biomass utilization.