if we perform experiment and suggests the order of adsorption capacity interms of mg/g, but if we see interms of mmol/g it would change because some time molecular weight is higher then other...explain how we compare or how we obtain in terms of mmol/g.e.g
Adsorption of metal ions in mg/g or mmol/g both are correct, but in case of comparison like HG>Pb>Cu as 52, 47 and 16 mg/g respectively. but when we convert into mmol/g it will become reverse as the molecular weight for Hg is 200, Pb is 207 and for Cu 63 respectively. the order will be reverse Cu>hg>pb.
Dear Mudasir,
you know that one mol of material has got 6,023*1023 particles and that the weight of all these particles, the mol-weight, is equal to the molecular weight of these particles in units of g/mol. (Please note: the molecular weight itself is a relative number and has no unit (i.e. unit is equal to 1); so far the numbers without unit presented in your question are ok.).
For your case these particles are metal ions ( Hg, Pb and Cu) having a mol-weight of 200g/mol, 207g/mol and 63g/mol respectively.
For conversion of the mg/g into mmol/g you have to divide the mg value by the appropriate mol-weight:
Hg: 52mg /(200g/mol)---> 52/200mmol= 0,26mmol
thus 52mg/g ---> 0,26mmol/g
Pb: 47mg/(207g/mol) ---> 47/207mmol= 0,23mmol
thus 47mg/g ---> 0,23mmol/g
Cu: 16mg/(63g/mol) ---> 0,25mmol
thus 16mg/g ---> 0,25mmol/g
You are right: the order of Hg > Pb > Cu ( in mg/g) is changed,, but into
Hg > Cu > Pb (in mmol/g),
which is a little bit different to your result (may be a typing error).
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