optimizing cadmium (cd (ii)) removal from aqueous solutions using activated matoa (pometia pinnata) fruit peel: kinetics, isotherms and batch adsorption study

Cadmium (cd (ii)) contamination presents a significant environmental and health risk due to its toxic effects on ecosystems and human well-being. developing effective removal methods is crucial to mitigate these risks, and using organic waste as an adsorbent provides an environmentally sustainable solution. this study explores the adsorption capacity of matoa fruit peel (pometia pinnata), which was activated using 0.01 m hno₃, to remove cd (ii) from aqueous solutions in a batch adsorption process. the process was optimized by analyzing the influence of various factors, including ph (3–7), initial cd (ii) concentration (50–250 ppm), and contact time (10-240 minutes). the results, analyzed using atomic absorption spectroscopy (aas), were fitted to kinetic models and adsorption isotherms. optimal conditions were achieved at ph 6, with a maximum adsorption capacity of 9.43 mg/g, a concentration of 200 ppm producing an adsorption capacity of 12.50 mg/g, and an ideal contact time of 150 minutes resulting in a capacity of 12.39 mg/g. the freundlich isotherm model (r²=0.994) best described the adsorption process, indicating multilayer physisorption. the adsorption kinetics followed a zero-order model. this study demonstrates that matoa fruit peel is a promising, low-cost adsorbent for the efficient removal of cadmium from water.