In this study, biochar and magnetic biochar were used to remove methylene blue from the aqueous solution. This study also presents the preparation of biochar and magnetic biochar. Biochar and magnetic biochar used as adsorbent substances were obtained from loquat seeds (Eriobotrya japonica). The prepared adsorbent materials were characterized using SEM-EDS, BET, XRD and FT-IR. The effects of pH, time, amount of biochar and magnetic biochar, initial methylene blue (MnB) concentration and temperature were investigated. The sorption of MnB on biochar of Eriobotrya japonica seeds (b-ER) and iron-modified (mb-ER) is an endothermic process. R2 values, calculated and experimental adsorption capacity values were compared (R2 = 0.992 b-ER-MnB and R2=0.983 mb-ER-MnB) b-ER and for mb-ER the MnB adsorption process was found to fit the pseudo-second order-kinetic model. It was found to be more suitable for Langmuir adsorption isotherms when the adsorption isotherms were investigated. The maximum adsorption capacity was 40.650 ± 2.036 mg/g for b-ER-MnB and 81.697 ± 4.085 mg/g for mb-ER-MnB. According to the results obtained, mb-ER can be used effectively in the removal of methylene blue from aqueous solutions.