Phosphorus is a non-renewable element essential for the existence of life and also for food security. This resource has the property of limiting plant growth, becoming a fundamental part of agricultural production. On the other hand, when this element is present in high concentrations in aquatic environments, it can start a phenomenon called eutrophication, which causes a series of changes in biological succession processes and strongly negative impacts on species’ biodiversity and wealth. In this context, this work aimed, from an extensive bibliographical review, to gather strategic and essential information related to phosphorus sustainability, provoking a reflection regarding scenarios that involve this indispensable nutrient, focusing on the current situation of the State of São Paulo, Brazil, an important case study, both for the Brazilian and international scenario, by a gathering of data on the current situation of two of the main watersheds in the corresponding region. Relevant technologies used for phosphorus removal in eutrophicated environments are also addressed. Finally, the possibility of reusing the nutrients present in eutrophicated water bodies as an alternative source of phosphate fertilizer for agriculture is demonstrated. nonrenewable non renewable security growth production hand eutrophication species wealth context aimed review sustainability nutrient Paulo Brazil study scenario region addressed Finally demonstrated

In this work, we investigated the use of cotton scraps in natura and modified with iron nitrate, in the adsorption of one of the main water contaminants of the textile industries, the reactive black dye. Special attention was paid to the appropriate destination of the spent adsorbent, in compliance with the precepts of the circular economy. Cotton and polyester are excellent candidates for adsorbents and are produced on a large scale worldwide, but fabric wastes do not yet have a well-established method of application. We found that fabrics containing different types of fibers or colors maintain the ability to remove dye. The retention promoted by the cotton fabric in natura reached 18.8 mg g-1. After treatment with iron ions, there was an increase in the dye adsorption capacity to 31.0 mg g-1. In addition, the spent iron-containing adsorbent was pyrolyzed at 973 K, resulting in an activated magnetic carbon with a specific surface area ranging from 300 to 565 m2 g-1. Thus, it was possible to convert the used adsorbent into a new material with wide application possibilities.