Heavy metals (Cd, Cu, Pb) adsorption capacity experiments with a novel adsorbent Unfertilized Mango Flowering Buds (UMFB) were investigated in a batch scale studies at different constraints to obtain prime conditions of adsorption dose, initial metals concentration, contact time, pH, and temperature. The results showed that increasing the dosage of UMFB to 6 g/L enhanced the removal efficiency of Cd, Cu, and Pb to 82.46%, 65.74% and 74.99% respectively. The ideal biosorption limits were seen at pH 5–6 with efficiency up to 80.77%, 69.41% and 71.05% for Cd, Cu, and Pb respectively. The capacities of heavy metals removal, on the other hand, were found to be 14.51 mg/g of UMFB for Cd, 12.57 mg/g of UMFB for Cu, and 12.98 mg/g of UMFB for Pb. The ideal estimations of contact time were found at 120 min. The respective removal rates of Cd, Cu and Pb were 82.77%, 73.26%, and 79.64% while the respective adsorption capacities of Cd, Cu and Pb were 14.44, 12.65 and 13.07 mg/g. The highest accepted initial metal concentration that can achieve acceptable metal removal was not the same for the all tested metals: 100, 50, and 200 g/L for Cd, Cu, and Pb respectively. The results showed that the most suitable sorption temperature is at 40°C with a removal rate of 80.90% and 75.75% for Cd and Pb respectively, and at 60°C for Cu with a removal rate of 77.32%. The coexisting ions weakened the removal efficiency of Cd due to the intense competition for adsorption sites. Characterization of the UMFB has been conducted by scanning electron microscopic (SEM) images, before and after loaded of heavy metals, showed significant changes in the surface morphology, indicating the adsorption process had taken place. Fourier transform infrared spectroscopy (FTIR) indicates the organic functional groups which might be involved in the adsorption of heavy metals. Both pseudo-first and second-order models were used to evaluate the adsorption mechanism of different metals. It was found that information fitting best to pseudo-second-order model since the R2 was almost equal to unity. The Cd, Cu, and Pb adsorption behavior on UMFB was a ch