Alternatives for the reduction of Cu(Ⅱ) ion levels in hemodialysis membranes produced from sugar-cane bagasse

摘要

The objective of the present study was to seek alternatives for the reduction of Cu(Ⅱ) ion levels in hemodialysis membranes produced by the cuprammonium process. The alternatives used were: (a) replacement of the solvent Cu(NH_3)_4(OH)_2, used in the original process, with Cu(EDA)_2(OH)_2, and (b) increasing the reflux time of the bagasse purification process from 1.5 to 3.0 h. The experimental results were obtained by analysis of Cu(Ⅱ) content in the membranes by atomic absorption, by complexometry via UV/Vis spectroscopy of the solutions of filter paper, bagasse and lignin, and by monitoring the various stages of the purification process (by FTIR and by loss of mass), i.e. pretreatment with 0.25 M NaOH followed by treatment with 4.2 M EDA and reflux with EtOH/HNO_3 (20%, v/v). The results showed that the Cu(Ⅱ) content in the membranes decreased with the use of the Cu(EDA)_2(OH)_2 solvent, that the purification process could not be improved further since cellulose degradation was observed, and that the Cu(Ⅱ) content in the membranes produced was still to high for their use for hemodialysis treatment.