Microbial Recovery of Copper from Printed Circuit Boards of Waste Computer by Acidithiobacillus ferrooxidans

Abstract

The bioleaching of copper contained in the printed circuit boards (PCB) of waste computers by A. ferrooxidans was studied. The Fe oxidation rates by A. ferrooxidans in the 9K medium supplemented with the leachate of PCB (0.15-0.13 g L(-1) d(-1)) were similar to that in the 9K medium without the leachate (0.15 g L(-1) d(-1)). This finding suggests that the leachate of PCB did not seriously affect the bioleaching process by this bacterium. The amount of copper leached from PCB shreds increased with the addition of ferrous ion and reached up to 5190 mg L(-1) when the initial concentration of Fe2+ ion was 7 g L(-1). As the microbial leaching progressed, pale brown precipitate was observed to form in the solution. Based on the total amount of copper, both in solution and precipitate, the optimal addition of ferrous ion for the leaching of copper was around 7 g L(-1). When citric acid was not added, only about 37 wt% of the total leached copper remained dissolved; however, the amount of dissolved copper increased to greater than 80 wt% in the presence of citric acid. This fact indicates that the addition of a complexing agent (citric acid) to the bioleaching solution can raise the solubility of the leached metal ions.

Leaching Processes

“…Recent research has shown that the action of acids in the bioleaching process is of influence on the solubilization rate of the metal [75,87]. According to Saidan et al [75], in a pH of 2, bio-metabolized organic acids lead to a better dissolution of the copper coming from printed circuit boards than sulfuric acid, which is the result of bacterial action.…”

“…Agitated flasks [62] Sulfobacilllus thermosulfidooxidan, Thermoplasma acidophilum, and Sulfobacilllus acidophilus [63] Sulfobacilllus thermosulfidooxidans and Thermoplasma acidophilum Columns [65] Acidophilus bacteria Agitated flasks [59] Acidithiobacillus ferrooxidans [89] Acidithiobacillus ferrooxidans [87] Sulfobacillus thermosulfidooxidans and unidentified acidophilus bacteria (code A1TSB) […”

Geri̇ Dönüşüm Sektöründe Cevher Hazirlama Teknoloji̇leri̇ni̇n Kullanimi

“…Yapılan araştırmalar incelendiğinde, eatıkların hidrometalurjik yöntemle geri kazanımı 1960'lara kadar dayanmaktadır ve bu proseslerde metal içeriği kuvvetli sülfürik asit, hidroklorik asit, nitrik asit, aqua regia ve alkalileri içeren liç çözeltilerinde çözülebilmektedir [33]. Son 20 yılda ise yapılan araştırmalar da bioliç yöntemlerinin e-atıklardan metallerin kazanımında etkili rol oynadığı da ortaya konmuştur [33][34][35][36].…”

Lixiviação Bacteriana De Sucata Eletrônica: Influência Dos Parâmetros De Processo

“…Estudos de lixiviação bacteriana (18)(19)(20)(21)27) reportam taxas de extração acima de 70% com condições de agitação variando entre 150 rpm a 250 rpm; porém, utilizando velocidades de rotação de 150 rpm e 160 rpm, a extração do cobre diminu para menos de 60%. Lixiviação bacteriana de sucata eletrônica: influência dos parâmetros de processo A Figura 4 mostra que o aumento na concentração inicial de íon ferroso não aumenta a extração de cobre, como seria esperado, já que atividade biológica está estritamente ligada à oxidação do íon ferroso.…”