నైరూప్య

Removal Of Chromate Ions From Waste Water With Coupled Transport Of Liquid Membranes At Different Stirring Speeds And Temperatures

Menderes Levent, Sahset Irdemez, Nuhi Demircioglu

In this study, the non-steady state kinetics of the coupled transport of chromate (CrO4 -2) ions through liquid membranes (n-hexane 90 %, chloroform 10 %) containing benzyltrimethyl ammonium chloride (BTMACl) as a carrier was examined at stirring speeds ranging from 100-250 rpm and temperatures 293-308 °K. In this study, the influence of stirring speed and temperature on the kinetic parameters( k1d , k2m , k2a , tmax , Rm max, Jd max, Ja max) have been investigated. The transport efficiency of chromate ions increased with increasing stirring speed. The membrane entrance and exit rate constants (k1d , k2m and k2a respectively) were linearly depent on the stirring speed ratios of 100 to 250 rpm. The membrane entrance(k1d) and exit rates (k2m , k2a) have been increased with temperatures. For maximum membrane entrance (Jd max) and exit (Ja max) fluxes, the activation energies of membrane entrance and exit permeate rates for chromate ions were calculated from the slopes of the two linear relationships : Ead = 11.82 kcal/ mol and Eaa = 8.38 kcal/mol, respectively. The values of the calculated activation energy indicate that the process is kinetic controlled at the membrane entrance and it is diffusionally controlled at the membrane exit .The membrane was stable during the transport experiments (no leakage of carrier or chromate ion-carrier complex to both aqueous phases and also, no supplementary water penetration into the membrane). This favours interfacial reaction of chromate ion and carrier.