Study On The Adsorption Effect And Mechanism Of Typical PPCPs By Modified Construction Waste Bricks

In recent years,as a new type of pollutants,PPCPs have been detected in water environments,and the cause of environment problems raised more and more attentions.With the rapid development of urbanization in China,construction wastes received more and more attention.It was necessary to mitigate its hazards and utilize it resourcesly.In this thesis,the typical construction waste-construction waste bricks were used as carriers to load iron oxides and surfactants.Two typical PPCPs,cimetidine(CTD)and diclofenac(DCF),were target pollutants.The adsorption efficiency and mechanism of CTD and DCF from water were studied.And the main conclusions were as follows:(1)PRBP,GCBP and HCBP were prepared successfully,and the removal efficiency of CTD in water was studied.The results showed that the specific surface area of the adsorbenst decreased after the modification,but the pore volume and the content of iron oxide was increased.The adsorption of CTD onto GCBP,HCBP and PRBP reached equilibrium in 4h,and the kinetics were consistent with the pseudo-second-order kinetic model,Langmuir model fitted the adsorption data better.This showed that the adsorption of CTD onto three adsorbents was a monolayer chemical reaction.The pH value and ionic strength of the solution affect the adsorption process of CTD significantly.the optimal pH value is 6.0,and the ionic strength will inhibit the adsorption.(2)Based on the above studies,the adsorption effectiveness and mechanism of DCF by three adsorbents were studied in depth.The experiment data showed that the maximum adsorption capacities of HCBP,GCBP and PRBP were 292.3,220.5 and 187.9 ?g/g.The coated iron oxides promoted the adsorption of DCF effectively,and the effect of HCBP was better.The adsorption of DCF onto three adsorbents increased rapidly within 5h,the adsorption fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model,which indicated that the adsorption was a monolayer chemical reaction.The adsorption of DCF on three adsorbents decreased with the increased of temperature,and the adsorption process was an exothermic reaction.With the increased of pH,the adsorption amount decreased rapidly.As the ionic strength increased,the adsorption amount increased first and then decreased.(3)CCBP was prepared successfully.The adsorption of DCF by PRBP and CCBP was studied.It was found that the maximum adsorption capacity of DCF on CCBP was 33mg/g,which was much higher than 0.19mg/g of PRBP.The adsorption of DCF reached equilibrium in 2h,and the experiment data was fitted with the pseudo-first-order kinetics model and the Langmuir isotherm model,which indicated that there was a physical chemistry reaction in the adsorption process.The adsorption amount of DCF decreased with the increase of temperature,and the adsorption process was exothermic reaction.The p H and ionic strength of the solution both inhibit the adsorption of DCF significantly.CCBP removed DCF efficiently through physical and chemical adsorption and electrostatic interaction.