ZINC (II) Recovery from Aqueous Solution Using Continuous FOAM Fractionator

In  the  present  investigation,  recovery  of  zinc  (II)  ions from  zinc  plating  effluent  was  carried  out  in  a  continuous foam  column  using  sodium  lauryl  sulphate  as  surfactant.  The effect  of  various  experimental  parameters  such  as  air  flow rate,  liquid  pool  height,  feed  concentration,  surfactant concentration,  pH  of  the  feed  and  feed  flow  rate  on  the enrichment  of  metal  ions  was  investigated.  Enrichment  ratios of  9.2  and  8.9  with  a  percentage  removal  of  around  99%  and 95%  were  obtained  for  the  removal  of  zn(II)  ions  from synthetic  aqueous  solution  and  zinc  plating  effluent  at  the optimum  operating  parameters  of  30  cm  liquid  pool  height  in column,0.1  liters  per  minute  (Lpm)  of  air  flow  rate,  feed  flow rate  of  4  liters  per  hour  (Lph),  0.1  %  (w=v)  of  SLS concentration,  pH  of  6.0  and  at  feed  concentrations  of  10  ppm zinc(II)  ions.  Enrichment  ratio  was  found  to  increase  with  an increase  in  feed  flow  rate.  With  a  decrease  in  concentration  of the  bulk  solution,  the  separation  factor  was  found  to  increase. The  study  indicates  the  feasibility  of  continuous  foam separation  for  treating  industrial  effluents.  Also  from  our earlier  investigations,  it  was  observed  that  the  zinc  has  higher enrichment  ratio  and  percentage  removal  than  that  of  copper or  chromium  due  to  stronger  complex  formation  of  copper  or chromium  with water  molecule is also discussed.