Fabrication Of Double-cross-linked Microcrystalline Cellulose Embedded MgAl Layer Double Oxides Aerogel For The Removal Of Methyl Orange And Cr（Ⅵ）

The pollution of organic dyes in water seriously endangers the aquatic environment and human health,and is often accompanied by heavy metal pollution.The situation to deal with the wastewater in combination of organic dyes and toxic heavy metals is complicated.In view of the above situation,adsorption method is an effective one to treat water pollution due to its advantages of simple operation,economical and effective removal.Thus,the preparation of a cost-effective adsorbent with excellent properties is the key to the high efficiency of the adsorption method.Cellulose is rich in raw material sources and microcrystalline cellulose（MCC）as a typical cellulose is purified from it.Especially prepared as microcrystalline cellulose aerogel demonstrating recyclable and does not produce secondary pollution.It is a good base material for sewage treatment.If supplemented by appropriate adsorption performance improvement,it has broad application prospects in the removal of organic dyes and heavy metal pollution.Layered double metal hydroxide（LDH）is cheap and easy to obtain,and its unique layered structure is conducive to interlayer ion exchange.Through high temperature calcination from LDH,layered double metal oxide（LDO）shows better adsorption.To realize the full potential of microcrystalline cellulose（MCC）adsorption capacity,novel ternary hybrids,double cross-linked microcrystalline cellulose/Mg Al-LDO aerogels（PEI-PMCC/LDO）,were fabricated by a facile method and applied for the removal of orange methyl（MO）and Cr（Ⅵ）from aqueous solution.In order to analyze the morphology,chemical composition,functional groups and properties,PEI-PMCC/LDO aerogels were characterized by SEM,FTIR,XRD,XPS,TGA and zeta potential analysis.Through batches of experiments,the effects of environmental factors were taken into consideration,including initial p H value and concentration,contact time with contaminants as well as environmental temperature on the adsorption of methyl orange and Cr（Ⅵ）on PEI-PMCC/LDO.Besides,models of adsorption thermodynamics,adsorption kinetics and thermodynamic parameters were involved to investigate the adsorption mechanisms during the adsorption processes.Owing to the abundant amino and phosphate groups on the surface of MCC aerogel as well as positively charged Ma Al layered double oxides（LDO）,PEI-PMCC/LDO demonstrated satisfying removal efficiency of methyl orange and Cr（Ⅵ）.The maximum capacity obtained at the optimal adsorption p H of raw solution toward methyl orange and Cr（Ⅵ）on PEI-PMCC/LDO were 451.2 and 164.9 mg/g,respectively,much high than that of27.8 and 6.6 mg/g on MCC.From the linear fitting results of the experimental data,it’s clear that the adsorption processes better fitted the Langmuir model and pseudo-second-order kinetics.In addition,from the results of thermos dynamic studies,the adsorption process of methyl orange on PEI-PMCC/LDO was spontaneous endothermic,while that was spontaneous exothermic to Cr（Ⅵ）on PEI-PMCC/LDO.In addition,the mechanisms of adsorption were proposed to be combined by various adsorption mechanism between the adsorbents and the adsorbate.Meanwhile,PEI-PMCC/LDO aerogel showed high removal efficiency after four runs of recycling experiments.The indicative adsorption capacity,reusability and thermal stability features make PEI-PMCC/LDO aerogels promising adsorbents in organic dyes and heavy metals pollution removal treatments.