Recovery of tannins from leather industry by ultrafiltration

ESTELA ROMERO DÓNDIZ; JORGE E. ALMAZÁN; VERÓNICA B. RAJAL; ELZA CASTRO VIDAURRE

Londres

Congreso; EUROMEMBRANE 2012; 2012

Introduction The leather tanning industry is characterized as one of the most polluting industries. This is due to inefficient use of chemicals in the process and to the various organic substances derived from it [1]. Particularly, the tanning process involves high consumption of water and of chemicals most of which are later found in the tannery effluents since they are added in excess to ensure complete chemical reaction with leather collagen. Tannins are natural polyphenols with molecular weight ranging between 500 and 3000. The presence of these compounds in wastewater can cause many problems associated with environmental pollution and effluent treatment. The recovery of the tannins using membrane processes is interesting from the environmental viewpoint, because tannic compounds in solution are present as anionic dispersion, preventing their flocculation with common polyelectrolytes. This phenomenon is reduced by decreasing the concentration of tannin compounds below 2% w/w in the wastewater [2] The aim of this study was to evaluate the ultrafiltration as an alternative for the recovery of tannins in the leather industry.