The adsorption isotherms of lignosulfonate on kaolinite and
coal were determined to explain whether the different behaviour
of lignosulfonate in the flotation of the problematic coal using
deionised water and process water was related to surface adsorption. Results are shown in Fig. 5. The particle size of the substrates
is different. Therefore, it may not be possible to directly compare
the adsorbed amount of lignosulfonate onto different substrates.
However, it is possible to compare the adsorbed density of lignosulfonate onto the same substrate in deionised water and saline
water