Two-dimensional zeolitic imidazolate framework-8 for efficient removal of phosphate from water, process modeling, optimization, kinetic, and isotherm studies

摘要

Having unique properties, metal-organic frameworks are recognized as interesting materials for many applications. Leaf-shaped zeolitic imidazolate framework-8 (L-ZIF-8) with a 16.66 m(2)/g Brunauer-Emmett-Teller (BET) surface area and total pore volume of 0.0572 cm(3)/g was synthesized in aqueous medium and room temperature. L-ZIF-8 then used for P removal from aqueous solutions and a polynomial prediction model for phosphate (P) removal was developed by designing the experiments using central composite design. The model terms showed an increase in P removal with adsorbent dosage and contact time and also by decreasing pH. The highest P removal after model optimization determined to be at pH 4, L-ZIF-8 dosage 0.6 g/L, and 84 min contact time. The isotherm models indicated a monolayer adsorption of P onto L-ZIF-8 with a maximum 51.24 mg P/g of adsorbent. Study of P removal dynamic revealed that the process controlled by chemisorption.