Abstract The focus of this study is to evaluate the efficiency of oxidation processes in the treatment of a solution containing Rhodamine-B (RhB) used in various industrial applications. The advanced oxidation processes of electrooxidation (EO) and photoelectrooxidation (PEO) were used. At the same time, direct photolysis (DP) was also applied. Total organic carbon (TOC) reduction and color removal were evaluated. There was an efficient color removal when DP was performed, and the color removal efficiency was the highest when NaCl was used as supporting electrolyte for PEO and EO. However, the TOC reduction was low, indicating that the degradation of the color does not correspond to the pollutant mineralization.

Nos dias atuais, há uma infinidade de modelos, tamanhos e configurações de equipamentos eletro-eletrônicos disponíveis para o consumo. Visando a realizar a reciclagem e o reaproveitamento dos metais preciosos encontrados nas placas de circuito impresso (PCI) dos celulares, esse trabalho tem o objetivo de caracterizar o ouro presente nas PCI dos aparelhos celulares e desenvolver uma rota de reciclagem para o ouro e a prata, utilizando reagentes alternativos ao cianeto, como o tiossulfato de sódio e tiossulfato de amônio. Esses reagentes agridem, numa menor intensidade, o meio ambiente e a saúde do trabalhador. Primeiramente realizou-se uma caracterização com água-régia. Os resultados mostraram 86.26g Au/tonPCI e 123.85g Ag/tonPCI. Na segunda caracterização, foi utilizado o reagente comercial a base de cianeto e o resultado foi de 112.02g Au/tonPCI e 26.13gAg/tonPCI. Para a lixiviação com tiossulfato de sódio, chegou-se ao resultado de 9.02g Au/tonPCI, na lixiviação do ouro, e de 33.88g Ag/tonPCI, na lixiviação da prata, comparando com os resultados da caracterização usando reagentes a base de cianeto.

Nowadays there is a wide variety of models, sizes and configurations of mobile phones available for consumption. After the life cycle of this equipment, the recycling and reuse of the precious metals found in the printed circuit boards (PCB) of the mobile phones are principal objectives. Thus, the objective of this work was to characterize the gold and silver present in a PCB and develop a recycling route using alternative reagents for cyanide, such as sodium and ammonium thiosulfate. These reagents are less harmful to the environment and worker health. The first characterization of gold and silver was performed with aqua regia. The results show 86.26g Au/ton of PCBs and 123.85g Ag/ton of PCBs. The second characterization was performed with a commercial cyanide-based reagent and 112.02g Au/ton of PCBs and 26.13g Ag/ ton of PCBs were obtained. A leaching study with solutions based on thiosulfate was performed and an extraction of 9.02g Au/ton of PCBs and 33.88g Ag/ton of PCBs was obtained, compared to characterization results using a cyanide-based reagent.