Removal Of Doxycycline Hydrochloride From Water By Mn Ox-loaded Biochar

In recent years,the occurrence and pollution of antibiotics in the environment have become public concern all over the world,because of their potential to cause ecosystem alteration by challenging microbial populations.Antibiotics may induce the formation of antibiotics resistant bacteria in the long-term exposure.The main sources of antibiotics include industry,hospital and household,which are widely used in improving the human health,preventing and treating infections.Due to their variable physicochemical properties and complicated structures,doxycycline have complex behavior in the water environment,making them difficult to remove from natural water environments.As a fast,efficient,economical and environmental method in wastewater treatment,adsorption has attracted special interest in removing DOX from the aquatic environments.In this study,manganese oxide?MnO_x?nanoparticles loaded biochar was applied for doxycycline hydrochloride?DOX?removal from water.Biochar composites were synthesized by pre-treating biomass using MnCl₂/KMnO₄/NaOH?PMBC?.The biochar loaded with MnO_x exhibited superior adsorption properties for doxycycline.The adsorption capacity of PMBC was about 104 mg/g,which was about nonuple and tenfold higher than that of raw biochar?11.48 mg/g?.PMBC was characterized using SEM,TEM,XRD,FI-IR,BET surface area and zeta potential measurements.Several experimental conditions?solution pH,adsorption time,temperature,ionic strength and foreign ions?affecting the adsorption process were investigated.The characterization indicated that PMBC have better surface structure and surface functional groups than raw biochar.Main sorption mechanisms of DOX to PMBC were surface complexation,H-band,?-?interaction and electrostatic interaction.The DOX removal by PMBC also involved degradation of DOX.In complex water environments,the presence of heavy metals may affect the removal of antibiotics.Cu?II?and Cr?V??were used to study the effect of DOX removal.The presence of Cu?II?obviously enhanced the DOX adsorption capability through Cu?II?bridging effect,while the presence of Cr?V??significantly inhibited DOX adsorption through competitive adsorption and electrostatic repulsion.The results suggested that PMBC could be implemented as a cost-effective and environmentally friendly adsorbent for DOX removal from water.And heavy metal ion can obviously enhance or weaken the DOX adsorption capability.