Study On Preparation Of Quaternized Cellulose-graft-poly(glycidyl Methacrylate),adsorption And Flocculation Properties

As one kind of resourceful,biodegradable and renewable material,cellulose could be rendered with enhanced physical,chemical and biological properties through chemical modification such as etherification,esterification and graft polymerization.Cellulose-based derivatives with versatile adsorption and flocculation behavior could be attained by introducing adsorptive and flocculative side chains as well as groups onto molecular backbones of cellulose,which has become focus in research upon technology for treatment of wastewater and sludge.In this paper,cellulose-graft-poly(glycidyl methacrylate)(Cell-g-PGMA)has been prepared through free radical-initiated graft polymerization of glycidyl methacrylate from microcrystalline cellulose with higher grafting percentage,while graft polymerization conditions were optimized.When 1 g of cellulose was used,initiator concentration and monomer concentration were 0.0269 mol L-1and 2.3449 mol L-1,graft percentage and graft efficiency could be increased to 420.1%and 84.02%,respectively at 70?.Cell-g-PGMA was further quaternized with trimethylamine,yielding quaternized cellulose-g-poly(glycidyl methacrylate),QD-Cell-g-PGMA,which has been verified with FT-IR,elemental analysis,SEM and TG/DTG,while adsorption of thus prepared QD-Cell-g-PGMA for anions and flocculation property have also been evaluated.Adsorption properties of QD-Cell-g-PGMA such as adsorption kinetics,isotherms,thermodynamics and regeneration of QD-Cell-g-PGMA for methyl orange(MO),a model anionic dye,have also been investigated.Experimental results showed that kinetic adsorption followed pseudo-second-order model and adsorption isotherms fitted well with Langmuir model,from which maximum adsorption capacity could be derived as 1333.3 mg g-1 for MO at 28?.Furthermore,thermodynamic parameters indicated that adsorption process for MO onto QD-Cell-g-PGMA was spontaneous and endothermic.In addition,the adsorbent can be easily regenerated by eluting dilute NaOH solution(0.5 mol L-1)through saturated adsorbent and removal efficiency of 89.32%could be maintained after four cycles of adsorption-desorption,indicating viable option of efficient adsorbent for anionic contaminants from wastewater.Moreover,flocculation properties of QD-Cell-g-PGMA for kaolin suspension were also studied,including influence of flocculation time,QD-Cell-g-PGMA concentration,and initial pH on residual turbidity.Experimental results exhibited that residual turbidity of kaolin suspension could be decreased from 1151 NTU to 7.493 when QD-Cell-g-PGMA concentration was 3 mg L-1,initial pH was 7 and flocculation time was 10 min at room temperature,diaplaying satisfactory flocculation performance of QD-Cell-g-PGMA for kaolin suspension.In summary,QD-Cell-g-PGMA thus prepared in this paper revealed excellent adsorption for MO and flocculation property for kaolin suspension,applicable for removal of anionic contaminants from wastewater and sludge as efficient adsorbent and flocculant.