A new metal-organic framework (MOF) with the chemical formula of[Ni2F2(4,4'-Bipy)2(H2O)2](VO3)2·8H2O was introduced to adsorb Pb(Ⅱ) with the highest capacity.The sorbent was characterized by thermogravimetric analysis (TGA),infrared spectroscopy (FT-IR),field-emission scanning electron microscopy (FESEM),energy-dispersive X-ray (EDX),and elemental analysis.The optimum conditions were obtained by a face-centered central composite design (FCCD) as follows: adsorbent dosage (m) =12 mg,initial concentration of Pb(Ⅱ) (C) =390 mg·L-1,and pH =5.According to the Langmuir model (R2 =0.9999),the maximum monolayer uptake capacity of lead(Ⅱ) is 2400.7 mg·g-1,which is the highest observed amount for lead(Ⅱ) adsorption.Neither of the old adsorbents for lead(Ⅱ) has the uptake capacity over 2000 mg·g-1.The model of pseudo-second-order describes well the process kinetics.The adsorption process of lead (Ⅱ) is independent of temperature changes.This compound can adsorb lead (Ⅱ) from tap water.In addition to introducing a new MOF with the highest uptake capacity for removal of Pb(Ⅱ) that is the outright novelty of this study,the concurrent modeling of both the removal percent (R) and the uptake capacity (q) is another important advantage.Because it achieves the more economical and favorable optimum conditions in comparison with the single optimization of each response.