title: A fast and environment-friendly method for determination of chemical oxygen demand by using the heterogeneous Fenton-like process (H2O2/Fe(3-x)Co(x)O4 nanoparticles) as an oxidant.
abstract: An easy, fast and environment-friendly method for COD determination in water is proposed. The procedure is based on the oxidation of organic matter by the H2O2/Fe(3-x)Co(x)O4 system. The Fe(3-x)Co(x)O4 nanoparticles activate the H2O2 molecule to produce hydroxyl radicals, which are highly reactive for oxidizing organic matter in an aqueous medium. After the oxidation step, the organic matter amounts can be quantified by comparing the quantity of H2O2 consumed. Moreover, the proposed COD method has several distinct advantages, since it does not use toxic reagents and the oxidation reaction of organic matter is conducted at room temperature and atmospheric pressure. Method detection limit is 2.0 mg L(-1) with intra- and inter-day precision lower than 1% (n=5). The calibration graph is linear in the range of 2.0-50 mg L(-1) with a sample throughput of 25 samples h(-1). Data are validated based on the analysis of six contaminated river water samples by the proposed method and by using a comparative method validated and marketed by Merck, with good agreement between the results (t test, 95%).
authors: Instituto de Ciência, Engenharia e Tecnologia, Universidade Federal dos Vales Jequitinhonha e Mucuri, Teófilo Otoni 39803-371, Minas Gerais, Brazil.
authors: Lorena C R
authors: LC
authors: Esteves
authors: Instituto de Ciência, Engenharia e Tecnologia, Universidade Federal dos Vales Jequitinhonha e Mucuri, Teófilo Otoni 39803-371, Minas Gerais, Brazil.
authors: Thaís R O
authors: TR
authors: Oliveira
authors: Instituto de Ciência, Engenharia e Tecnologia, Universidade Federal dos Vales Jequitinhonha e Mucuri, Teófilo Otoni 39803-371, Minas Gerais, Brazil.
authors: Elias C
authors: EC
authors: Souza
authors: Instituto de Ciência, Engenharia e Tecnologia, Universidade Federal dos Vales Jequitinhonha e Mucuri, Teófilo Otoni 39803-371, Minas Gerais, Brazil.
authors: Cleide A
authors: CA
authors: Bomfeti
authors: Instituto de Ciência, Engenharia e Tecnologia, Universidade Federal dos Vales Jequitinhonha e Mucuri, Teófilo Otoni 39803-371, Minas Gerais, Brazil.
authors: Andrea M
authors: AM
authors: Gonçalves
authors: Departamento de Química, ICEx, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
authors: Luiz C A
authors: LC
authors: Oliveira
authors: Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040903 SP, Brazil.
authors: Fernando
authors: F
authors: Barbosa
authors: Instituto de Ciência, Engenharia e Tecnologia, Universidade Federal dos Vales Jequitinhonha e Mucuri, Teófilo Otoni 39803-371, Minas Gerais, Brazil.
authors: Márcio C
authors: MC
authors: Pereira
authors: Instituto de Ciência, Engenharia e Tecnologia, Universidade Federal dos Vales Jequitinhonha e Mucuri, Teófilo Otoni 39803-371, Minas Gerais, Brazil. Electronic address: jairo.rodrigues@ufvjm.edu.br.
authors: Jairo L
authors: JL
authors: Rodrigues
mesh_terms: D057919:Biological Oxygen Demand Analysis; D003035:Cobalt / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*
chemical_list: D016877:Oxidants; D010087:Oxides; D003035:Cobalt; D006861:Hydrogen Peroxide; D007501:Iron; C060728:cobalt oxide
keywords: Chemical oxygen demand; Contamination; Magnetite; Organic matter; Oxidation