HBPEI Modified Waste Fiberboard Activated Carbon For Enhanced Adsorption Of Chromium

Activated carbon has been widely used in wastewater treatment,owing to its good adsorption performance.Research has showed that the adsorption performance of activated carbon could be improved by the way of amination,especially the adsorption for metal ions.This paper studied the method of modification by using hyperbranched polyethylenimine to modify activated carbon obtained from waste fiberboard,and the adsorption performance of modified waste fiberboard activated carbon for Cr(VI)was also further studied.Waste fiberboard containing 12%ureaformaldehyde resin adhesive was used as the raw material to prepare activated carbon.Hyperbranched polyethylenimine(HBPEI)was grafted onto the surface of waste fiberboard activated carbon(WFAC)by glutaraldehyde(GA)crosslinking method.The modified conditions were investigated,and the optimal conditions of modification were;HBPEI molecular weight 10000g/mol,HBPEI/WFAC(w/w)0.5,GA concentration 0.25%,reaction time 60min.In addition,the Cr(VI)adsorption property onto modified WFAC contained the factors of pH value,contact time,and Cr(VI)concentration,adsorption kinetics and modeling,adsorption isotherms and regeneration quantity were investigated.The results of FTIR and XPS demonstrated that HBPEI was chemically bonded onto the WFAC surface by the glutaraldehyde crosslinking method,and the atomic ratio of C:N:O turned to 80.04:6.65:13.31 from 54.25:0.72:45.03 after modifying WFAC showing the obvious increase in nitrogen after modification.However,the BET surface area of modified WFAC declined slightly from 1868.36m2/g to 1647.21m2/g.The data analysis of Roman spectroscopy indicated that the modification process had no significant effect on the graphitization of activated carbon and the ID/IG of modified WFAC decreased from 0.92 to 0.82.Analysis of the Cr(VI)adsorption data was well simulated by the pseudo-second-order kinectic model and Langmuir adsorption isotherm model compared with Freundlich adsorption isotherm model.And its maximum Cr(VI)uptake was 500mg/g.The adsorption uptake of Cr(VI)-loaded modified waste fiberboard activated carbon after one regeneration cycle by chemical method was 309.75mg/g,corresponding to 90%of the original modified waste fiberboard activated carbon.This paper only used chemical method to regenerated Cr(VI)-loaded WFAC,we can try other regeneration methods to improve the efficiency of regeneration in the future research.In the aspect of application,this modified material can be applied to wastewater treatment containing other pollutants,electrode material,pretreatment and purification of analysis sample,etc.