Adsorption of hexavalent chromium by dry biomass of Methylorubrum rhodesianum JABV-01

• Grant number: 24/18837-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2025
• End date: January 31, 2026
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Luciana Maria Saran
• Grantee: Ana Luiza Girardi de Araujo
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

Chromium (Cr) is one of the most widespread potentially toxic metals in aquatic ecosystems, mainly in the oxidation states +3 and +6, with Cr(VI) being mutagenic and carcinogenic. The adsorption of Cr(VI) by biological material (plant or microbial residual biomass) has been widely studied, aiming at the recovery and reduction of Cr(VI) concentration in wastewater. Thus, considering that our research group has evaluated the production of molecules of biotechnological interest by the Methylorubrum rhodesianum JABV-01 strain and that the residual microbial biomass has been discarded, the present research proposal aims to study: i) the production of Methylorubrum rhodesianum JABV-01 biomass by cultivating the strain in a medium prepared with water from washing barley malt bagasse (BMB), and ii) the use of dry biomass of Methylorubrum rhodesianum JABV-01 as a Cr(VI) adsorbent. The bacterial strain will be cultivated in a medium containing fructose as a carbon source and in media prepared with BMB washing water as a substitute for fructose. The characterization of dry bacterial biomass will be performed by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and by the zero-charge point. The adsorption tests will be performed in batch mode, with a standard Cr(VI) solution in the form of potassium dichromate, at constant temperature and stirring speed. It will be studied the effect of the initial pH of the Cr(VI) solution, contact time, initial concentration of this metal ion, and dose of the biosorbent, adopting the central composite rotational design. The process kinetics and adsorption isotherms will be studied too. The results obtained from the development of this proposal can contribute to sustainable water management. Furthermore, no reports on the use of Methylorubum rhodesianum biomass for the adsorption of potentially toxic metals were found in the literature.