Preparation Of Magnetic Cellulose Composites For The Adsorption Of Anionic Dyes In Wastewater

In recent years,with the rapid development of economy and the great improvement of people’s living standard,water pollution has become an urgent problem to be solved.In this paper,cellulose,widely existed in nature,is used as substrate to be loaded with magnetic nanoparticles,and a series of adsorbent materials based on magnetic cellulose complex were prepared.In addition,this work explores the adsorption performance of anionic dyes wastewater and revealed the influence rules.Specific research work includes:(1)A new environmental-friendly magnetic cellulosic adsorbent MnFe2O4@Cel-g-p(AADMC)was easily synthesized via natural cellulose and easy-recovered magnetic particles MnFe2O4.The results showed that the optimal pH of the adsorbent was 3,the removal efficiency of Congo red(CR)could be improved by peroxomonosulfate(PMS),the optimal concentration was 0.20 g/L,and the maximum adsorption capacity was 60.24 mg/g.The adsorption kinetic model was well-fitted to the pseudo-second-order model,and the adsorption isotherm were matched with the Freundlich isotherm model.The cyclic experiment proved that the adsorbent could be used under the external magnetic field and the removal efficiency remained stable after four cycles.Besides,the main adsorption mechanism of CR was chemical adsorption,and there were physical adsorption,electrostatic attraction,hydrogen bonding,n-π interaction and activation mechanism of PMS in the system.The MnFe2O4@Cel-g-p(AA-DMC)possesses the excellent stability,reusability and superior superparamagnetic behavior and its possible adsorption mechanism for the adsorption of CR was proposed.(2)A green and efficient adsorbent(FSIL@CP)with porous structure and cationic charge was prepared for the adsorption of anionic dyes Congo red(CR)and methyl blue(MB).The adsorption kinetics and isotherm models were well-fitted to pseudo-second-order model and Langmuir isotherm,the maximum adsorption capacities for Congo red(CR)and Methyl blue(MB)reached 1299.30 and 1068.10 mg·g-1,respectively,which was better than other similar adsorbents reported in the literature.The adsorption process followed multiple-stage intraparticle diffusion with spontaneous feature,the possible adsorption mechanisms of FSIL@CP with CR and MB were electrostatic attraction,hydrogen bonding and physical adsorption.The adsorbent could be rapidly and easily separated from aqueous solution under external magnetic field.The regeneration performance of the adsorbent was excellent and could be repeatedly used.Therefore,the adsorbent was expected to be used in the treatment of anionic dye wastewater.(3)A new adsorbent(FSCS-cl-p(MB A-co-BVI))was prepared by grafting N,N’-methylene bis(acrylamide)(MBA)and 1-butyl-3-vinyl-imidazolium ammonium bromide(BVI)with magnetic sepiolite/cellulose complex.In brief,the adsorbents were suitable within the range of 3-9 and reach adsorption equilibrium during 120 min.Meanwhile,the maximum adsorption capacity for CR was up to 1374.10 mg/g at 45℃.Furthermore,the adsorption kinetics and isotherm models were well-fitted to pseudo-second-order model and Langmuir isotherm model,respectively.The adsorption mechanisms of FSCS-cl-p(MBA-co-BVI)for CR could be interpreted as electrostatic attraction,hydrogen bonding and π-π stacking interaction.Based on results,the as-obtained adsorbents were effective,inexpensive and expected to be applied to the treatment of dyestuff.