The coagulant protein from Moringa oleifera (MO) seed was purified using a single-step batch ion exchange (IEX) method. Adsorption and elution parameters were optimized. Impact of the purification on the reduction of organic and nutrient release to the water was studied. The matrix was equilibrated using ammonium acetate buffer, and the optimum ionic strength of NaCl for elution was 0.6 M. The time for adsorption equilibrium was between 90 and 120 min. Maximum adsorption capacity of the matrix, estimated with the Langmuir model, was 68 mg protein/g adsorbent. The purified protein does not release organic and nutrient loads to the water, which are the main concerns of the crude extract. This work suggests that a readily scalable single-step IEX purification method can be used to produce the coagulant protein and it can be carried out with locally available facilities. This will promote the use of MO in large water treatment plants and other industries.