The adsorption potential and equilibrium data modeling of a low cost biowaste adsorbent Ziziphus mauritiana seed powder (ZMSP) without any pretreatment as pretreatment of a biowaste also add to the wastewater treatment cost has been investigated. Batch adsorption studies have been carried out to determine adsorption potential using cationic dye methylene blue (MB) as adsorbate. Equilibrium is achieved in 180 min. It is found that adsorption increased with the increase in amount of adsorbent as well as increase in pH value. The experimental data for the ZMSP is fitted well to the Langmuir adsorption isotherm followed by Freundlich, Temkin and Dubinin-Raduskevich. On the basis of parameter E of Dubinin-Raduskevich isotherm it has been found that chemisorption is the phenomenon involved in the removal of dye. Pseudo second order and Elovich model fitted better than Pseudo first order kinetic model. Surface properties of the adsorbent have been characterized by SEM, EDX, BET analysis, and FTIR. It has been found from the experimental investigation that Ziziphus mauritiana seeds have a potential to be used as a cost effective adsorbent. Its adsorption capacity has been found to be comparable with other low cost adsorbents reported in the literature.