The characteristics of wastewaters, collected from
radiator manufacturing, Ni(II) and Cu(II) plating industries
are summarised in Tables 1±3. The removal of
heavy metals from undiluted industrial wastewaters depended
upon the composition, and pH. The pH experiment
showed maximum removal of 73% for Cu(II),
100% for Hg(II), Pb(II ) and Cd(II) and 92% for Ni(II)
by coirpith carbon at pH 5.0 for Cu(II), 4.0 for Pb(II),
3.5 for Ni(II) and Hg(II), and 4.0 for Cd(II). In the pH
range 4.0±5.0 maximum adsorption was observed, due
to the partial hydrolysis of metal ions resulting in the
formation of M(OH) and M(OH)2. M(OH)2 would
have adsorbed to a greater extent on the non-polar
surface than would M(OH). In the acidic pH range,
2.0±3.0, there would be a competition between H and