When mangoes are consumed or processed, their peels and seeds are generated as waste. The waste is an environmental concern, but is a natural and renewable resource. In this project, a process was developed to convert mango seeds into carbonized adsorbents. The effectiveness of mango seed-derived carbon in wastewater treatment was evaluated. Water containing methylene blue was treated with mango seed-derived carbon. The concentration of methylene blue in the water was monitored by a do-it-yourself “spectrophotometer”.