This study explores the potential of modified shrimp-based chitosan (MSC) as an innovative adsorbent for removing heavy metals (Cu, Zn, Cd, Pb) from contaminated water sources. The modifications include chemical treatments, surface functionalization, and structural optimization to enhance chitosan's adsorption capabilities. Comprehensive analyses using FT-IR and SEM-EDS were conducted to evaluate the properties of the chitosan. The adsorption capacity of MSC was assessed using ICP-MS before and after the adsorption process. The study investigated the efficiency of heavy metal removal under different conditions, including variations in pH, adsorbent dosage, and contact time. Under neutral pH conditions, the highest adsorption rates were determined as 99.72% for Cu, 84.74% for Zn, 91.35% for Cd, and 99.92% for Pb, with corresponding adsorption capacities of 20.30 mg/g, 7.50 mg/g, 15.00 mg/g, and 76.34 mg/g, respectively. Langmuir and Freundlich isotherm models revealed highly significant adsorption of heavy metals, supported by strong correlation coefficients (r² > 0.98). The pseudo-second-order kinetic model with linear coefficients (r² > 0.97) effectively explained the kinetic studies of metal adsorption using modified shrimp shells. FT-IR spectroscopy confirmed the presence of specific functional groups on the adsorbent, such as N–H joined with –COO–, H–O, C–O–C, and C–H. SEM-EDS analysis detected the presence of elements on the surface of MSC chitosan. The results emphasize that MSC is a highly effective and cost-efficient adsorbent for eliminating Cu, Zn, Cd, and Pb from wastewater, making it a promising eco-friendly choice.This study explores the potential of modified shrimp-based chitosan (MSC) as an innovative adsorbent for removing heavy metals (Cu, Zn, Cd, Pb) from contaminated water sources. The modifications include chemical treatments, surface functionalization, and structural optimization to enhance chitosan's adsorption capabilities. Comprehensive analyses using FT-IR and SEM-EDS were conducted to evaluate the properties of the chitosan. The adsorption capacity of MSC was assessed using ICP-MS before and after the adsorption process. The study investigated the efficiency of heavy metal removal under different conditions, including variations in pH, adsorbent dosage, and contact time. Under neutral pH conditions, the highest adsorption rates were determined as 99.72% for Cu, 84.74% for Zn, 91.35% for Cd, and 99.92% for Pb, with corresponding adsorption capacities of 20.30 mg/g, 7.50 mg/g, 15.00 mg/g, and 76.34 mg/g, respectively. Langmuir and Freundlich isotherm models revealed highly significant adsorption of heavy metals, supported by strong correlation coefficients (r² > 0.98). The pseudo-second-order kinetic model with linear coefficients (r² > 0.97) effectively explained the kinetic studies of metal adsorption using modified shrimp shells. FT-IR spectroscopy confirmed the presence of specific functional groups on the adsorbent, such as N–H joined with –COO–, H–O, C–O–C, and C–H. SEM-EDS analysis detected the presence of elements on the surface of MSC chitosan. The results emphasize that MSC is a highly effective and cost-efficient adsorbent for eliminating Cu, Zn, Cd, and Pb from wastewater, making it a promising eco-friendly choice.