[Cd(Ⅱ) Ion Adsorption and Sealing onto SBA-15 Mesoporous Particles and the Related Potential on Cd(Ⅱ) Polluted Soil Remediation].

Aiming to expand the utilization of porous silicate minerals in the remediation of heavy metal contaminated soil,the mesoporous material SBA-15 was successfully synthesized by using sodium silicate as silica source in this study.And the obtained SBA-15 samples were characterized by TEM,X-ray diffraction,N adsorption-desorption and FTIR.Furthermore,characterization of Cd (Ⅱ) adsorption and sealing performance onto SBA-15 were evaluated through batch experiment,and the remediation potential of Cd (Ⅱ) contaminated soil was investigated by brassica planting in a pot experiment.The results showed that SBA-15 had the mesoporous structure with surface area of 507.3 m·g and pore size of 7.38 nm.The maximum Cd (Ⅱ) adsorption capacity was 76.43 mg·g at pH above 7.0 with the adsorption isotherm fitting the Langmuir model in the solution of 100 mg·L Cd (Ⅱ).The increase in ionic strength reduced the Cd (Ⅱ) adsorption capacity.The Cd (Ⅱ) loaded SBA-15 could be regenerated with 0.1 mol·L HNO,while Cd (Ⅱ) could be strongly sealed in the pore structure after introduction of sodium silicate into the system.The pot experiment proved that the addition of SBA-15(4.5 g·kg) into Cd-contaminated soil could reduce Cd (Ⅱ) availability,enhance the transformation of soluble and exchangeable Cd (Ⅱ) fractions into carbonate and Fe-Mn oxides bounded forms,inhibit the Cd (Ⅱ) accumulation in the plant tissue and improve the brassica growth.Based on these results,it can be concluded that combination of the SBA-15 particle with sodium silicate has great potential to remediate Cd (Ⅱ) contaminated soil through adsorption and sealing properties.