<p>This study explores the effect of pH modification on corncob biochar for nutrient retrieval from human urine and blackwater, with a focus on nitrogen and phosphorus adsorption. Results showed that neutral pH offered optimal nitrogen adsorption capacities (10.702 mg/g from human urine and 3.014 mg/g from blackwater) while pH 9 maximized phosphorus adsorption (3.691 mg/g from urine and 1.698 mg/g from blackwater). The presence of calcium, magnesium, and surface functional groups enhanced adsorption through a combination of physical and chemical mechanisms. Both pseudo-first and pseudo-second-order kinetic models effectively described the adsorption process, with <i>R</i>² values exceeding 0.85. Desorption experiments produced nutrient-rich solutions, notably with 143.703 mg/L nitrogen and 235.101 mg/L phosphorus. These findings highlight the potential for using biochar to retrieve nutrients from wastewater, offering prospects for optimizing biochar composition and pH for selective adsorption in future studies.</p>