Effects of Crystalline Structures and Surface Functional Groups on Ionic Dyes Adsorption By Superparamagnetic Particles Comparing with Modified Mesoporous Silicates

摘要

Effects of surface functional groups and crystalline structure of silica coated superparamagenic nanoparticles (SCPs) on adsorption of ionic dyes (Acid Blue 45 and Basic Yellow 1) were investigated from synthetic wastewater, comparing with modified mesoporous silicates (HMSs). Nanosize magnetite (Fe_3O_4) was coated by silica matrix to combine adsorption characteristic with magnetic separation. SCP surface was modified by grafting 3-aminopropyltriethoxy-groups (AM-SCP). Five different single surface functional groups of HMSs were studied, i.e., silanol, n-octyldimethyl-, 3-aminopropyltriethoxy-, 3-mercaptopropyl- groups and Titanium substituted HMS (HMS, OD-HMS, AM-HMS, MP-HMS and Ti-HMS, respectively) and three different ratios bi-functional groups (A3M7-HMS, A5M5-HMS and A7M3-HMS) were applied. Increasing hydrophobicity of porous silicate materials can increase BY adsorption capacities. 3-aminopropyltriethoxy- groups grafted on surface can enhance adsorption capacity of Acid Blue 45. Accessible internal surface area of AM- HMS can also increase Acid blue45 adsorption capacity. Adsorption capacity of acid blue 45 on AM-SCP was independent of surface charge. On the contrary, adsorption capacities of Acid Blue 45 on SCP were influenced by changing of pH. The cationic dyes (Basic yellow 1) can also be adsorbed on SCP and AM-SCP; however, only adsorption on AM-SCP was strongly influenced by surface charge, whereas, changing pH didn't affect to Basic Yellow 1 adsorption capacities on SCP.