Adsorption of Pb2+ and Cu2+ on anionic surfactant-templated amino-functionalized mesoporous silicas

Amino-functionalized mesoporous silicas (AFMS) were synthesized using the anionic surfactantN-lauroylsarcosine sodium (Sar-Na) as template and 3-aminopropyltrimethoxysilane (APTMS) as costructuredirecting agent (CSDA). Orthogonal experiments were applied to optimize the synthesis ofAFMS with high amino loading, high surface area, and large pore size. The synthesized AFMS were characterizedby FT-IR, TG-DTA, XRD, N2 adsorption–desorption, and TEM techniques. The removal of Cu2+or Pb2+ from aqueous solutions by the synthesized AFMS was investigated in detail. The pH value of anaqueous solution containing Cu2+ or Pb2+, adsorption temperature, and the dosage of the used AFMSaffect the removal efficiency of Cu2+ or Pb2+ greatly. The unary adsorption isotherms of Cu2+ and Pb2+ onthe optimized AFMS adsorbent are well described by the Sips isotherm model, in which the adsorptioncapacities are 2.18 and 4.74 mmol/g for Cu2+ and Pb2+, respectively, under the optimized conditions, muchhigher than the literature data. Furthermore, the AFMS adsorbent shows a good stability, confirmed byadsorption–regeneration cycles. Based on these excellent properties, the application in the removal ofCu2+ and Pb2+ from wastewater is anticipated.