Preparation Of Biochar And Carbon Sphere-supported Aluminum-based LDH And Its Adsorption Performance On Ibuprofen

With the adjustment of national policies for the prevention and control of the new coronavirus epidemic and the current spread of influenza A,ibuprofen（IBU）has become one of the most commonly used antipyretic drugs.As a typical non-steroidal anti-inflammatory drug,due to the stable nature of IBU,it shows false persistence in water bodies,further endangering aquatic ecosystems and human health.At present,a variety of technologies are used to remove wastewater from pharmaceutical plants containing IBU,and adsorption technology has attracted wide attention because of its advantages such as simple operation,no additional treatment facilities,and no secondary pollution.The performance of adsorbents is the key to adsorption technology,and the adsorbents commonly used at present include activated carbon,chitosan,cyclodextrin,etc.,among which carbon-based materials have a stronger ability to remove hydrophobic organic pollutants.In contrast,biochar and carbon balls not only meet the advantages of carbon-based materials,but also have the advantages of low energy consumption,simple preparation and low cost,but their low adsorption capacity limits the adsorption capacity of IBU.In recent years,layered double hydroxides（LDHs）have attracted much attention in the field of adsorption,because of their unique layered structure and good ion exchange ability,the research on the adsorption of anions and heavy metals has gradually increased,but LDHs have less research on the adsorption of organic pollutants,especially in non-steroidal anti-inflammatory drugs.The disadvantages of LDHs are heavy quality and poor dispersion effect.In view of this problem,on the basis of co-precipitation method,two aluminum-based LDH materials are loaded onto two carbon-based materials of different shapes,the influence of carbon-based composites of different shapes on the adsorption effect is studied,and the adsorption mechanism of IBU molecules by the adsorbent is elaborated while comparing the adsorption capacity.In this study,Zn Al-LDH and Ni Al-LDH were first loaded in situ on alkali-modified biochar KBC,and Zn Al-LDH-KBC and Ni Al-LDH-KBC of M²⁺:M³⁺=2:1（M is metal）were obtained after metal molar ratio optimization.The material characterization results showed that the surface roughness of the two composites increased after modification,and Ni Al-LDH-KBC had better thermal stability,larger specific surface area and pore size,and the pore structure was mainly mesoporous.The adsorption experiment showed that the adsorption effect of the two adsorbents gradually decreased with the increase of p H,but the adsorption performance of Ni Al-LDH-KBC was always better than that of Zn Al-LDH-KBC.In addition,the antibiotic norfloxacin（NOF）has no obvious effect on the adsorption performance of IBU,while soluble anions will significantly reduce the adsorption capacity of the material.Adsorption isotherm and kinetic fitting studies showed that the adsorption of IBU by Zn Al-LDH-KBC and Ni Al-LDH-KBC was dominated by chemical adsorption of monolayers,with maximum adsorption capacities of 171.203mg/g and 231.043mg/g,respectively.The thermodynamic results showed that with the increase of temperature,the adsorption chaos increased and the adsorption capacity increased.After five regeneration experiments,the adsorption effect was reduced by only 5%,and it still had a good adsorption effect.The analysis of XRD and FTIR characterization results showed that the material composition of the material before and after adsorption did not change,the structure was stable,and the adsorption mechanism of IBU was mainly hydrophobic,hydrogen bonding andπ-πEDA.In order to explore the effect of LDH supported by different forms of carbon-based materials on the adsorption capacity of IBU,Zn Al-LDH-CS and Ni Al-LDH-CS were prepared with carbon sphere CS as the substrate under the premise of molar ratio of 2:1.Through characterization analysis,it can be seen that the surface of Ni Al-LDH-CS is relatively smooth and the specific surface area is small.The adsorption results showed that the two adsorbents were seriously affected by p H and inorganic salts.From the adsorption kinetics and isotherms,the maximum adsorption capacity of Ni Al-LDH-CS reached 195.513mg/g,while Zn Al-LDH-CS was only 45.1115mg/g.Adsorption thermodynamics indicate that an increase in temperature is beneficial for adsorption.After five cycles,the adsorption capacity decreased.By comparing the adsorption effects of the four materials with commercial powdered activated carbon,it is found that the two Ni Al-LDH composites have fast adsorption rates and have the possibility of replacing activated carbon.In addition,the adsorption effect of other types of adsorbents on IBU was compared,and Ni Al-LDH-CS and Ni Al-LDH-KBC were applied to real pharmaceutical wastewater,which proved that the two materials have excellent IBU adsorption capacity while being inexpensive,simple to prepare,and synthetically green.