D. Petruzzelli et al., CHROMIUM REMOVAL AND RECOVERY FROM TANNERY WASTES - LABORATORY INVESTIGATION AND FIELD EXPERIENCE ON A 10-M(3) D DEMONSTRATION PLANT/, Water science and technology, 30(3), 1994, pp. 225-233
Citations number
8
Categorie Soggetti
Water Resources","Environmental Sciences","Engineering, Civil
After extensive laboratory investigation of an ion exchange based proc
ess for selective removal, separation and recovery of Cr(III), Al(III)
and Fe(III) from tannery wastes (spent chrome baths and leather washi
ng waters), a 10 m(3)/d mobile pilot plant was assembled to demonstrat
e technical reliability and economic feasibility of the process. The I
ERECHROM (Ion Exchange REmoval of CHROMium) process is based on a weak
electrolyte carboxyl resin, able to remove the metals from the liquid
effluent followed by selective separation and recovery during a regen
eration step. The resin is regenerated with alkaline hydrogen peroxide
brines (0.15 M H2O2, 1M NaCl, 0.3M NaOH, pH = 11) through an internal
oxidation of chromic species to chromate, whereas aluminium is co-elu
ted after hydrolysis as aluminate ion. Ferric species are not released
by the resin in these conditions and are easily regenerated by subseq
uent acidic elution (1M H2SO4). Aluminate is thus separated from chrom
ate ion in the alkaline spent regeneration eluate by pH adjustment to
8.5 and precipitation of aluminum hydroxide. In this paper the basic p
rinciples of the process are reported and the promising data obtained
with a 10 m(3)/d mobile demonstration plant running at a tannery site
in the Naples area.