Adsorption Behavior and Adsorption Mechanism of P4VP-SiO2 Particles to Acidic Amino Acids

Composite-type P4VP-SiO2 particles were synthesized by grafting of 4-vinyl pyridine (4VP) onto the surfaces of silica gel particles, and characterized with FT-IR, Zeta potential measurement. The adsorption behavior of P4VP-SiO2 particles towards aspartic acid and glutamic acid were studied with batch method. The experimental results show that there is high density of positive charge on the surfaces of the grafted particles P4VP-SiO2 in a wide pH range according to Zeta potential measurement, the grafted particles P4VP-SiO2 exhibit very stronger adsorption ability to acidic amino acids, aspartic acid and glutamic acid than neutral amino acids. The adsorption capacities of P4VP-SiO2 to aspartic acid and glutamic acid first increase and the decrease with the increase of pH value, and the adsorption capacity reach maximum value at pH=4. The maximum adsorption capacities for aspartic acid and glutamic acid are 280 mg/g and 230 mg/g, respectively. Raising temperature or increasing salinity leads to decrease of the adsorption capacity.