Carvão ativado de caroço de açaí na filtração de água fluvial: aplicação de um sistema simplificado como recurso para o ensino de Ciências Ambientais em escola ribeirinha Amazônica

Abstract

Access to safe drinking water remains a challenge for riverine communities in the Amazon, where limitations in sanitation infrastructure favor the use of untreated river water. In this context, this study aimed to analyze the construction of a low-cost filtration system for the simplified treatment of river water using activated carbon produced from açaí seeds (Euterpe Oleracea Mart.) and to assess its potential as a resource for Environmental Sciences teaching. This applied research adopted a qualitative and quantitative approach involving the production and characterization of activated carbon, the assembly and experimental evaluation of the filtration system, and physicochemical, microbiological, and morphological analyses. As part of the professional and applied nature of the research, an illustrated educational workbook was developed as an educational product, based on the experimental results and designed to guide the construction and use of the filtration system in school and community contexts. The filter consisted of a reused PET bottle, gravel, sand, filter media, limestone fragments, and activated carbon. For the system containing laboratory-produced activated carbon, the results showed a reduction in turbidity from 48.5 to 6.2 NTU (87.2%), apparent color from 132 to 30 CU (77.3%), and total solids from 210 to 95 mg L⁻¹ (54.8%). The systems containing laboratory-produced and artisanal activated carbons also adjusted the pH to the range established by Brazilian Ministry of Health Ordinance GM/MS No. 888/2021. Regarding the microbiological analyses, the results for total coliforms indicated the need for a complementary disinfection step, whereas Escherichia coli, detected in the raw water, was not detected after filtration in any of the three systems evaluated. Scanning electron microscopy revealed the development of pores and cavities after chemical activation, favoring adsorption processes. Laboratory-produced and artisanal activated carbons showed relevant performance compared with industrial activated carbon, indicating their potential application in simplified water treatment systems. It is concluded that the proposed approach integrates the sustainable use of an Amazonian agro-industrial residue, improvement of water quality, and development of a contextualized educational resource, contributing to Environmental Sciences teaching and to the dissemination of social technologies suited to the Amazonian context.