A model equation was developed through the use of first order differential equation formed from a mass balance equation to study the mass transfer rate of iron (iii) contaminants in manganese dioxide media. The model was able to predict the time required for the manganese dioxide adsorbent to reduce the level of iron in water to acceptable level of concentration as allowed by WHO. The model agreed with experimental data that increase in adsorbent dosage will increase the rate of transfer of the iron (iii) contaminants into the adsorbent and hence increase in the rate of reaction. The study also found out that efficiency of adsorbent increases as the dosage is increased and that at a particular time increase in adsorbent dosage lead to wastage of materials as it may not lead to increased adsorption. Hence the model can be used as an effective monitoring tool during experiments to help us note the time results are expected and when the adsorbent need regeneration. The model also utilizes the effect of contact time and concentration on the rate of iron (iii) contaminants transfer rate to the manganese dioxide. The model equation can be used to monitor the rate at which different adsorbent concentration dosage can influence the rate of iron (iii) contaminants removal from water