AbstractAromatic amino acid or primary aliphatic acid available on prunus armeniaca seed coat (PASC) powder is modified (MPASC) using thioglycolic acid and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) in the form of N-substituted 2-sulfanylacetamide derivative. Infrared (FTIR), scanning electron microscopy, EDX, and XRD techniques are used for characterization of PASC and MPASC. Synthesized material is identified by the change in peak position and deformation of N–H bending vibration of primary amines peak. Peak at 1601 cm−1 due to N–H bending vibration is deformed at1656 cm–1 due to change of the primary amine into amide by thioglycolic acid. Both PASC and MPASC are then utilized for removal of As(III) form water. Adsorption experiments were conducted at different values of adsorbent dose, contact time and pH values in order to study their influence on the uptake of arsenic by the PASC and MPASC adsorbents. The Langmuir maximum adsorption capacity for PASC and MPASC were found to be 125 and 142.85 mg/g, respectively. Sulfhydryl groups on MPASC indicate high affinity for As(III) ions.