Sistemas aquosos bifásicos, convencionais e à base de glicerol, aplicados a matrizes de interesse ambiental e econômico

Abstract

In the main metallurgical routes used in the recovery of metals from electronic waste, many problems of environmental contamination can be noticed in some stages of these processes. The traditional liquid-liquid solvent extraction (SX), which uses toxic, volatile and flammable substances, is an example. For this reason, the development ofprocesses more efficient and less harmful to the environment, capable of replacing traditional ones, becomes necessary. In this sense, this work proposes the use of the technique of Aqueous Two-Phase Systems (ATPS) as an alternative to the traditional liquid-liquid solvent extraction (SX) in the selective extraction of metals from electronic waste matrices. The ATPS composed of water, copolymer L64 and sodium sulfate, welldescribed in the literature and used in the extraction of metals, was used in the selective recovery of cobalt from electronic waste composed of nickel metal hydride (NiMH) batteries. In this stage of the work, the entire process of optimization of the extraction conditions was carried out and, in the optimum conditions, 99 % of cobalt extraction was obtained with a separation factor in relation to nickel (Co,Ni) of 9.34 x 103. In the second stage of the work, a polymer was synthesized from glycerol, wichwas used in a new SAB for the recovery of gold, nickel and dyes was developed. The percentages of extraction (% E) obtained for each of the metals, in the absence of extractant were, % EAu = 95 and % ECd = 2, and, in the presence of extractant, % EAu = 96 and % ECd = 88. Regarding the dyes methylene blue (MB), reactive red (RR), andbrilliant green (BG), all concentrated in the saline phase, and partition coefficient (K), were 114, 149 and 2050, respectively.