Adsorption Of Mo(?) By Mesoporous Silica Nanospheres And Its Application In DGT Technology

According to China's surface water environmental quality standards,the limit of molybdenum?Mo?is 0.07mg/L.The molybdenum pollution of drinking water sources is becoming more and more serious,and the water source is polluted,resulting in molybdenum poisoning,which seriously affects human health and safety.Therefore,the study on the removal,enrichment and measurement of Mo?VI?in water environment is of great significance.In this study,mesoporous nano-silica?MSN?was prepared by Stober method.The adsorption performance of MSN on Mo?VI?was investigated and a novel technology of diffusive gradients in thin-films?DGT?with MSN as the binding phase was developed for in situ enrichment and detection of Mo?VI?in environmental waters.The study of scanned electron microscopy?SEM?,infrared spectroscopy?IR?,thermogravimetric analysis?TGA?,and nitrogen adsorption desorption curve?BET?indicated that the synthesized MSN has a mesoporous structure,a spherical appearance,good thermal stability,and a specific surface area up to 1067.64m²/g;the adsorption of Mo?VI?by MSN showed good adsorption under strong acidic conditions;The adsorption of Mo?VI?by MSN accords with the quasi-second-order kinetic equation,and the correlation coefficient R² is between 0.9975 and 0.9996.The isotherm adsorption process can be described by the Langmuir model,the adsorption process is physical adsorption,spontaneous and endothermic,at a temperature of 298K,the maximum monolayer adsorption capacity is217.39mg/g.The diffusion coefficient of Mo?VI?in the dialysis membrane at 25°C is?6.52±0.42?×10^-6cm²·s^-1?n=5?.Using 0.05mol/L NaOH as the eluent for the adsorption of Mo?VI?on the binding gel,the elution efficiency reached 92.19%.MSN-DGT has an effective adsorption capacity of 444.59?g/cm² at pH=2-9.5 and ionic strength less than0.5mol/L.It has excellent adsorption performance and can be used for enrichment measurement of Mo?VI?in actual water environment.