Preparation Of MOFs/hydrogel Composites And Their Adsorption Of Antibiotic

Adsorption is an effective method for removing pollutants from the aqueous environment,and excellent adsorbents are the key to the successful implementation of the adsorption treatment.In recent years,metal-organic framework materials(MOFs)have been considered one of the most promising adsorbents for removing residual antibiotic contaminants from the aqueous environment due to their excellent skeletal structure,extremely high specific surface area,extremely high porosity,adjustable pore structure and abundant adsorption active sites.However,traditional MOFs materials are usually in powder or crystal shape and require the addition of heavy metal ions during preparation,resulting in poor processability and recyclability,and are prone to secondary contamination.Currently,using water gel materials with flexibility,high water absorption,and good formability to composite MOFs is an effective method to improve the stability and processability of MOFs materials.Based on this,this paper uses in situ method to prepare composite particles of four different MOFs and sodium alginate hydrogel material,compares their adsorption performances as aqueous environment antibiotic adsorbents,and systematically studies the adsorption performance and mechanism of ZIF-67/sodium alginate hydrogel for antibiotics.Details of the study are as follows:1.Four kinds of MOFs/sodium alginate hydrogel composites materials(HKUST-1/SA,MIL-101(Fe)/SA,ZIF-8/SA,ZIF-67/SA)were prepared by in situ growth method.The morphology and structure of the products were characterized.It was found that MOF crystal particles in MOFs/SA composite materials were clearly visible and evenly distributed in the hydrogel network structure.2.The adsorption capacity of the four kinds of MOFs/SA composites adsorbents for tetracycline and chlortetracycline hydrochloride in aqueous was explored.The results showed that cobalt-based MOFs/SA composite(ZIF-67/SA)had good antibiotic adsorption performance.Among them,the adsorption capacity for chlortetracycline hydrochloride can reach 540.66 mg/g.3.Taking chlortetracycline hydrochloride(CH)as the target pollutant,the adsorption performance of ZIF-67/SA was studied,and the influence behavior of various external factors on the adsorption effect was investigated.The results showed that the adsorption process conformed to Freundlich model and pseudo-second-order kinetic model,indicating that chemical adsorption dominated during the adsorption process and there were multiple layers of adsorption.The study of adsorption mechanism showed that van der Waals force,electrostatic interaction,framework coordination,hydrogen bond,π-π interaction and hydrogel adsorption jointly affected the adsorption of CH on ZIF-67/SA.In addition,metal ion leaching experiments were used to evaluate the stability of ZIF-67/SA composite materials.It was found that sodium alginate hydrogel matrix can effectively reduce the leaching of metal ions in MOF structure.Therefore,MOFs/SA composite materials have good water stability and can be used as antibiotic adsorbents for water environment antibiotic pollutant adsorption treatment.