Preparation Of Amino Hierarchical Porous Silica And Study Of Its Adsorption Propertie

At present,the water pollution is more and more serious,especially the waste water contains harmful pollutants,which brings great challenges to sewage treatment.Heavy metal and antibiotic pollutants are common pollutants in wastewater,which are high in some sewage and and pose a great threat to people’s health and ecological protection.At present,many methods have been used to treat such wastewater,such as ion exchange,membrane osmosis,chemical precipitation and so on.The effect has been well proved in practical application,but there are still some disadvantages more or less.With the progress of scientific research,adsorption has been widely concerned because of its low cost and high removal efficiency,and the core of adsorption method is the selection of adsorbent.Most of the adsorbents have high preparation cost and complicated synthesis process,which makes the adsorption limited in practical application.Therefore,the preparation of low cost and high adsorption efficiency adsorbent has become the future development direction of adsorption method in the field of environment.In this paper,cetyltrimethylammonium bromide（CTAB）and polyacrylic acid（PAA）organic complexes were used as templates,and tetraethoxysilane（TEOS）and3-aminopropyltrimethoxysilane（APTMS）were used as mixed silicon sources.Under alkaline conditions,multi-level mesoporous silica with amino functional groups was successfully synthesized.The template of the material was removed by Soxhlet extraction.The materials were characterized by Fourier transform infrared spectroscopy（FTIR）,scanning electron microscopy（SEM）,nitrogen adsorption and desorption,organic element analysis（EA）,and Small-angle diffraction analysis（SAXD）.The results showed that the materials before and after extraction were submicron spherical particles,and most of the spherical particles were concentrated in the range of 450–550 nm.The addition of amino has some side effects on the order of the material structure.Both materials have silica skeleton and amino functional groups,and organic template is effectively removed by Soxhlet extraction.The material after extraction has two different mesoporous pore sizes,3.4 nm and 46 nm,respectively,while the material before extraction has only about 30 nm large mesopores.The adsorption properties of the prepared materials were studied,and the aqueous solutions containing Cr（Ⅵ）and amoxicillin pollutants were treated respectively.The results showed that the adsorption effect of Cr（Ⅵ）on the material with CTAB organic template(C₁₆-N-MSS)was better.The optimal adsorption p H was2.0,and the adsorption equilibrium time was 50 min.The adsorption amount increased with the increase of temperature,and the maximum theoretical adsorption amount reached 78.6 mg/g.The results of adsorption kinetics and isothermal adsorption analysis showed that the adsorption process of Cr（Ⅵ）on C₁₆-N-MSS was easier.The adsorption mode may be the combination of monolayer adsorption and multilayer adsorption,and the chemical adsorption controls the adsorption rate.The adsorption thermodynamic results show that the adsorption process is an endothermic process.The removal of CTAB organic template material（N-HMSS）had better adsorption effect on amoxicillin.The optimal adsorption p H was 7.0,and the adsorption equilibrium time was 20 min.The adsorption effect increased first and then decreased with the increase of temperature,and the maximum theoretical adsorption capacity reached 24.4 mg/g.The adsorption kinetics and isothermal adsorption analysis showed that the adsorption process of N-HMSS on amoxicillin was easy.The adsorption mode was monolayer adsorption,and the chemical adsorption controlled the adsorption rate.The adsorption thermodynamics showed that the adsorption process was endothermic.In addition,the regeneration experiment results of the two kinds of adsorption materials show that they have good reproducibility and still have high adsorption capacity after repeated adsorption.The preparation process of C₁₆-N-MSS adsorbent is simple and the preparation cost is low.Compared with other adsorbents,C₁₆-N-MSS has excellent adsorption effect on Cr（Ⅵ）,and gives full play to the dual role of CTAB cationic surfactant as a template agent to guide the preparation of adsorbent and as a modifier to enhance the adsorption performance,which provides a new idea for the preparation of new excellent adsorbents in the future.At present,there are relatively few studies on the removal of antibiotics such as amoxicillin using silicon materials as adsorbents.N-HMSS adsorbents not only have abundant pore structures,but also have amino functional groups.Compared with other types of adsorbents,they have higher adsorption capacity for amoxicillin,which provides theoretical and data support for the development of silicon materials in the field of adsorption of antibiotics.