Study On Preparation Of Iron-based Materials Modified By Organic Matters And Its Application

Antibiotics are generally used in the treatment of human and animal bacterial diseases,but it is difficult to degrade through the metabolism of organisms.In addition,heavy metals are widely used in the industrial field,but without proper treatment or incomplete treatment,heavy metal pollution has posed a serious threat to the surface water and groundwater.Therefore,the removal of antibiotics and heavy metals at water environment has become emphasis in the field of wastewater treatment.Iron-based materials are used covering a wide range in the removal of antibiotics and heavy metals in wastewater due to the economic,high efficiency,availability and environmental friendliness.However,the small size zero-valent iron?ZVI?particles with strong reducibility are easy to lose reactivity due to its agglomeration and passivation.Furthermore,in order to reduce iron salt to obtain the effective iron-based materials with low valence,it is usually necessary to use excessive corrosive chemical reagents,and produce other toxic by-products and flammable and explosive gases?H₂?in the preparation process.Therefore,the iron-based materials modified by organic matters widely existed in nature were used to remove chloramphenicol?CAP?and hexavalent chromium?Cr?VI??in aqueous solutions,and the iron-based materials modified by humic acid?HA?and willow dead leaves?WL?were prepared by liquid-phase reduction method.Through a series of characterizations,the iron-based materials modified by HA could effectively load nanoscale zero-valent iron?nZVI?particles,improving the phenomenon that nZVI was easy to agglomerate and passivate.The iron-based materials modified by WL could avoid the use of excessive corrosive chemical reductants,and WL could effectively reduce iron salts,while supporting and immobilizing the effective iron-based components.The removal efficiency and reaction mechanism of single pollutant?CAP or Cr?VI??in aqueous solution by the iron-based materials modified by HA and WL were investigated,respectively.When the dosage of iron-based material modified by HA was 1.0 g/100 mL,the initial concentration of CAP was 30 mg/L and the pH was 3.0,the removal efficiency of CAP achieved 85.0%.The removal of CAP was mainly due to the denitrification and dechlorination by nZVI loaded on the surface of HA.When the dosage of iron-based material modified by WL was 1.0 g/45 mL,the initial concentration of Cr?VI?was 30 mg/L,the initial pH was 3.0 and the temperature was298.15 K,the removal efficiency of Cr?VI?achieved 100%.The removal of Cr?VI?was mainly due to the adsorption?or complexation?,reduction and coprecipitation of Cr?VI?by WL and the effective iron-based components immobilized on WL.In summary,the iron-based materials modified by HA and WL were successfully prepared,and the feasibility of removing CAP or Cr?VI?from aqueous solution were confirmed.This paper can provide experience and reference for the removal of antibiotics and heavy metals in aqueous solution usig iron-based materials modified by organic matters,and provide theoretical support for the application of iron-based materials modified by organic matters in actual wastewater.