Resumen

FRANCISCA, Franco M.  y  CARRO PEREZ, Magalí Evelín. Arsenic removal by coagulation-flocculation processes. Rev. Int. Contam. Ambient [online]. 2014, vol.30, n.2, pp.177-190. ISSN 0188-4999.

Arsenic and arsenical compounds are considered as carcinogenic and risky for humans according to epidemiological evidence related with the ingestion of arsenical water during a long period. In many places the only source of drinking water contains arsenic and, therefore, removal strategies have to be investigated. This work shows experimental results of coagulation-flocculation processes implemented to evaluate the efficiency in the removal of arsenic from drinking water. The main objectives include the evaluation of the relevant aspect that controls the removal efficiency. Experimental tests were performed with coagulant concentrations from 5 to 500 mg/L, solid particle concentrations from 0 to 6000 mg/L, and initial arsenic concentrations from 0.5 to 5 mg/L. These variables were simultaneously varied in more than 100 experiments. The efficiency in remediation ranged from 0% to 95%. Removal efficiency near 95% was obtained when using ferric chloride as coagulant, and was close to 80% when using aluminum sulfate as coagulant in arsenate solutions. The remediation efficiency decreased significatively when the ferric chloride concentration was higher than 50 mg/L in relation to the obtained results for aluminum sulfate for different type and concentration of soil particles. The highest removal efficiency were obtained at pH between 3 and 5 in oxidized solutions. Obtained results simulated by means of multiple linear regression analysis (R>0.90) allow determining that the main parameters that control the removal of arsenic from drinking water are coagulant concentration, pH, and solid particles concentration. Conversely, particle mineralogy and coagulant type have less significant effect on the removal by means of coagulation-flocculation mechanisms. Obtained results are relevant for the removal of As in water treatment plants as well as for the development of small scale filters.

Palabras llave : coagulants; remediation; test; regression; contaminant.