Removal and recovery of p-phenylenediamines developing compounds from photofinishing lab-washwater using clinoptilolite tuffs from Greece

Clinoptilolite tuffs from areas in Thrace region of Greece are compared with synthetic zeolites NaY and NH₄Y for the uptake of N4-ethyl-N4-(2-methansulphonamidoethyl)-2-methyl-1,4-phenylenediamin (sesquisulphate, monohydrate) with the trade name CD-3 for the purpose to be used for clean-up and recycling photo-finishing and photo-developing washwaters. The cation-exchange capacity is found to be 6.15-11.1mg/g for zeoliferous tuffs at equilibrium concentration of 50ppm CD-3 in aqueous solution compared to 65.0mg/g of NaY and 48.2mg/g for NH₄Y synthetic zeolites corresponding to the removal of CD-3 from 120 to 200l of 50ppm aqueous solution per kg of natural zeoliferous tuff; this capacity is only 6-10 times lower than type-Y synthetic zeolite. Initial rates of uptake are 20.8mg/l/min for natural and 38.5mg/l/min for synthetic zeolites. Regeneration levels of 55, 23, 35, and 33% are obtained for MCH, SF, NaY, and NH₄Y, respectively. The rapid and almost complete uptake of CD-3 from its aqueous solutions at low CD-3 concentrations by the natural zeolites is promising for such an application.