Iron influence on copper biosorption using anaerobic sludge and its microstructural characterization

With the purpose of determining the copper biosorption mechanism, iron influence on the bioremoval, and methane production in a batch system using an anaerobic sludge a systematic study was carried out. In addition, sludge was characterized before and after biosorption treatment by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). According to results, Fe(III) has effect on copper biosorption. At neutral pH and concentrations from 50 to >300mg/L, copper biosorption increases. However, at concentrations 300mg/L a reduction in biosorption is observed. During biosorption, Fe(III) does not have an effect on both methane production and methanogenic activity; consequently, it is possible establishing that methanogenic bacteria are active under these conditions. Results of analysis by EDS reveal the copper presence into diatoms (2.66w%). In addition, biosorption of copper is by means diatoms-bacteria-polimeric matrix, and it is also bioaccumulated into diatoms.